Linear Actuator for Continuously Variable Transmission (CVT)

1- Stroke?

2- The 300°C are a very high value can it be reduced by a screen between exhaust and device?

3- Why 20 years do you not accept maintenance?

4- The angle of 0.002"=5.6E-7° is impossible, or do you think in linear displacement corresponding angle?

5- The constrains lead to an increased price!

6- What is fast for you? acceleration ? speed?

7- Are there fluids under pressure available ? which kind? pressure? Properties?

I am in the conceptual ProtoType and Patenting stage. Thus the specifics are not 'fixed' per say.

Also note that a very high duty cycle is required. Basically it needs to be able to function continuously with a 100% duty cycle.

1- Stroke?

~ 10" 25 CM for the prototype.

2- The 300°C are a very high value can it be reduced by a screen between exhaust and device?

No. As before, the prototype is 'generic and thus I am designing it for the 'worst case scenario.'

3- Why 20 years do you not accept maintenance?

The design is a simple elegant one that will have a very long life cycle with little or no maintenance other than changing the lubricant. Thus I want to build the longest lasting design that I can into this sub-system. I would prefer a 'self adjusting mechanism' to compensate for wear be incorporated into it. Only if necessary will manual adjustments with a minimum of 10 years be accepted.

4- The angle of 0.002"=5.6E-7° is impossible, or do you think in linear displacement corresponding angle?

I recognize that this specification is normally given as an angle and not a linear measurement. So far the only mechanism that I have come up with that fulfills my requirements is a 'Lead Screw' type arrangement with precision 'ways' as is found on Lathes. I would prefer a simpler arrangement and one that is not as prone to error due to wear. If I have to utilize this type of arrangement, then there will have to be (self) adjusting mechanisms such as a gib or ??? to adjust, compensate and correct for wear as well as for wear in the lead screw and it's driven nut. My inclusion of this requirement is to negate any rotary motion from the lead screw that will also tend to make the linear shifting mechanism to rotate as well. Basically NO rotational movement of the linear shifting mechanism is tolerable.

5- The constrains lead to an increased price!

Yes, that is a challenge, but these specifications and restraints are required for normal effective operation. As in most cases, the lowest cost solution that fulfills the requirements is the best one.

6- What is fast for you? acceleration ? speed?

A linear motion of approximately 1" ~ 2.5 cm in ~ 250 milliseconds at most. The linear positioning will have to 'hit it's mark' the first time without subsequent correctional movements. I am building some slight linear positional aids/guides into the desired locations, but basically it will have to hit the correct position first time, every time and very quickly without subsequent corrections.

6- Are there fluids under pressure available ? which kind? pressure? Properties?

Hydraulic pressure as the motive force is not an option here. Also there is no room to allow for the hydraulic cylinders to protrude from both ens of the transmission. It will have to be ~ 12VDC

Other options are

A Cable or chain configuration with the linear mechanism riding on precision 'ways' similar to a lathe can also be used with a stepper motor and an internal idler sprocket or pulley at the end opposite the positioning stepper motor. This idler can also be under tension to compensate for wear and stretching of the chain or cable. A 'timing belt' is not possible due to the fact that it will be operating in and environment filled with a petroleum based lubricant. Though there is very little force required to move the shifter mechanism in a linear movement, accuracy IS paramount. I currently guestimate it at 10 pounds force maximum which should be a sufficient including an excess safety margin. Thus these also have a problem with wear and inaccuracies becoming enlarged with age and operation. As noted above an additional tensioner idler, or the one at the other end of the stepper motor to complete the circuit could be used and active linear position measuring and feedback used to compensate for such wear. However the lead screw and the driven nut on the linear shifter mechanism also is prone to increased inaccuracies with wear and tear, and (self) correcting active feedback will be required regardless of the mechanism used with the most expensive option likely being that of a lead screw and driven nut. A cable or chain may be cheaper to utilize especially when taking the wear compensation mechanism into account. The adjustable gib to compensate for wear of the linear positioners movement back and forth on the 'Lathe 'Ways'' can be made externally accessible and hence adjustable without opening up the transmission. I would really like to find a more cost effective solution a mechanism for the linear shifter to slide back and forth on with virtually no 'slop' or error introducing movement. Regardless, this mechanism must retain, hold and prevent any movement of the linear shifter mechanism in all planes except in the back and forth plain that it is designed to travel on. Hence it cannot just be something like rotating wheels that glide back and forth on the traveling ways/guides that it could be lifted up off of it. It MUST be restrained from any movement in all directions and planes other than the back and forth motion on one flat plane.

The lead screw arrangement has a mechanical advantage over the chain or cable drive due to the inherent 'mechanical advantage / (apparent leverage)' of such a screw mechanism. Thus the power of the stepper motor and the possibility of slow &/or incorrect positioning due to extreme conditions such as very cold ambient temperatures and the resultant significantly higher lubricant viscosity that the linear shifter will have to overcome. On the other hand the high speed/very short time period movement's required can be more easily accommodated by a chain or cable arrangement than the lead screw arrangement.

Hi DougRH,

High speed movement with 100% duty cycle is available in low mass dc servo motors in the all copper and insulator disc rotor pancake configurations. Some backlash in the motor gear train can be easily overcome or preloaded. Feedback from a digital magnetic absolute rotary encoder will provide the required accuracy and a low cost. One source for the encoder is Austria Micro Systems. See part number AS5215 at WWW.austriamicro.com. It provides 4096 bit resolution per 360 degrees rotation for under 7 USD in quantity with quadrature output signals or digital outputs are available in similar model encoders at similar costs. A drum and flat SS ribbon will convert the rotary motion out of the gear train into linear. A negator spring can provide tension in the ribbon. Temperature effects will have an effect on the ribbon and the 6 cm diameter disc permanent magnet depending upon material selected for the magnet. An MCU of your choice will accept commands and close the loop. The IC will need to be potted to avoid shorting by the metal laiden hydraulic fluid. The magnet strength could be shorted by an accumulation of magnetic particles. Some accomodation will likely be required for this.

Regards,

Luther M.

Hi Luther,

I thank you for your specifics, it is this sort of detail that I need to resolve. I will check out the specified recommendations and those similar to it very carefully. As you correctly ascertain, utilization of anything magnetic within the actual CVT will (eventually) be rendered ineffective and disabled due to the accumulation of fine metallic particles that inevitably end up loose and suspended in the lubrication due to normal wear and tear.

FYI: Some engines use a very simple but fairly effective solution of a magnetic oil drain plug to take these metallic particles out of the lubricating oil that significantly increase engine wear. They are easily whipped off during an oil change. These are available as an aftermarket item and are a VERY worthwhile, cost effective and beneficial 'investment'.

Due to the requirements of the high degree of accuracy of the linear positioning over the lifetime of the CVT, the 'feedback and correction' mechanism needs to be mounted on the actual linear element and not the rotary motive mechanisms. As noted this is a significant challenge due to environmental factors.

In spite of my initial posting referring to a rotary to linear mechanism, if at all possible I would prefer to find a (cost) effective purely linear solution to this application. To that end I have expanded my research into such devices and mechanisms.

(8 >) Health, Happiness, Contentment and Prosperity to You and Yours in this New Year and Decade (< 8)

could a dual action hydraulic cylinder mounted internally be employed? the axial positioning could be determined using 18 - 24V proximety probes mounted normal to a tapered section of the ram or a conductive follower. with a taper of 0.005" to 0.040" over the length of the active range, a changing DC gap voltage could be correlated to position and could be adjustable to compensate for wear or changes in conductivity of target material. all the above could survive in such an environment.

Please see my response #6

Using a hydraulic cylinder is not possible for a number of reasons, but your idea of a potential positioner is interesting though I doubt if it has fine enough resolution and accuracy for my needs.

There is also the question of how much 'intelligence' to build into the transmission controls. If it was being done by and for just one company, then only the minimum would suffice and the majority of the logic could be offloaded to a central CPU etc. But I intend to license this technology to as many auto and other manufacturers as possible; so having as much of the required controlling logic inherent with the CVT and a high level API that requires the minimum of monitoring and input by off board logic is advantageous. This includes the operation of a very high speed 'automatic' clutch with a very high duty cycle and long life. A 'band clutch' (brake) might be an excellent solution for this application. This latter factor will make a significant difference in maximizing and utilizing the advantages of the very wide range of this CVT. This CVT will have several dozen 'gear ratio's as opposed to several gear ratios. Additional identical elements can readily be added to both increase the load capacity and the ratio range of this CVT. When accelerating across an intersection form a complete standstill it will likely make a minimum of 6 'gear changes' in that very short distance and time. Thus though this transmission could be configured and used as a manual transmission, it is not at all practical. Hence this CVT will in effect be an ''automated' manual transmission'.

Some factors to consider for your suggested positioning sensing and feedback:

The transmission will contain a petroleum based lubricant with dielectric properties. The amounts of this dielectric in proximity and in between the elements will vary very quickly and constantly during operation that may cause erroneous sensing.

Over an extended period of time normal wear and tear will introduce metallic ferrous metals of varying sizes (generally very fine) into the inside of the transmission. These will either be thrown onto the sensing elements directly or carried there suspended in the dielectric lubricating oil which will always be thrown around very vigorously during operation.

Seems that he should have designed software. We wouldn't have had all the problems with windows, it would have been done right the first time.

I'm not sure what you are referring to. Please explain.

Although being a fan of hydraulics I consider that for the force and the temperatures you mention it will NOT be a good solution.

Forces being so small (are you sure about the magnitudes?) I would suggest the use of the under-pressure generated by the engine. Same is used in the control of superchargers and it works very well in the whole range. The Actuator will not be a available of the shelf since for the application an actuation in + and - direction will be used (reverse). For superchargers only one direction is used. It could be possible to use a pair but I do not know if the possible dynamics will be sufficient.

I cannot go further in the analysis without the complementary information required. Of course suggestions can be made but they remain qualitative and as far as it is not known what is really expected such suggestions are at the most of limited value.

I am fairly well versed in hydraulics including their incredible power to weight ratio. Again for reasons previously stated, hydraulics is not a feasible solution for this application. Please see my response #6.

I have the feeling that you did NOT read my comment since you send me to the comment where you discard the hydraulic solution so that I allow myself to present it once more:

"Although being a fan of hydraulics I consider that for the force and the temperatures you mention it will NOT be a good solution.

Forces being so small (are you sure about the magnitudes?) I would suggest the use of the under-pressure generated by the engine. Same is used in the control of superchargers and it works very well in the whole range. The Actuator will not be a available of the shelf since for the application an actuation in + and - direction will be used (reverse). For superchargers only one direction is used. It could be possible to use a pair but I do not know if the possible dynamics will be sufficient.

I cannot go further in the analysis without the complementary information required. Of course suggestions can be made but they remain qualitative and as far as it is not known what is really expected such suggestions are at the most of limited value."

As you see I say NO to hydraulics and suggest the use of the aspiration depression present in every engine using air for the combustion.

I considered this could be a solution since it requires no source of additional power and low electric consumption for pilot valves. The dynamics you expect could be too high for it. The whole stroke could also be a problem. In fact I would not throw the solution away without a quantitative analysis to see where are the limits.

If I look at all the constrains you list I see in fact only one solution which is coherent with almost all of them but has to be analysed in details: it is a special electrical linear actuator with integrated feed back and no backlash. This can be imagined working with DC current but requires, due to the imposed stroke, a special design and a microprocessor control which will consider the differences between the actual position and the target optimising the force versus displacement profile in order to reach in the shortest time the target without overshot (for the analysis an estimation of the moving mass would be necessary not only for the force since the control has to consider the kinetic energy in the "slider" in the "braking" phase). This requires a non linear adaptive control possible to be made with a specific algorithm and variable control loop parameters.

I may be wrong but again I consider that the temperature (300°C) and the MTBF or MTBM (10 years) you expect are too important for a low cost target. Only as information usual insulation for solenoid wires will NOT be able to work at this temperature for such a long time if you also consider the increase due to the losses during active phases. With respect to the MTBM supplementary information is needed: how do you imagine the cycles as partial strokes, frequencies and number per for instance unit of the car travel (per mile or per km) and how many miles or km do you consider per year?

A last comment will be the voltage of 12V. The trend goes to higher voltages up to 42V, which allows a more compact design. I think that for the future 24 V solutions should be looked at.

I have a question concerning the future of the project. If anybody from CR4 finds a solution will you honour it when the product goes in series or when you get a compensation for selling your patent or from your royalties? It is of course only a question, pure curiosity.

Hi,

On the contrary I did fully and completely read your response and understood it quite clearly and it is not a suitable power/motive force for this device. For one thing with hybrids becoming more common, there will be significant circumstances where the engine will not even be running while the CVT is in use and needs to 'shift gears' This also includes other inventions of mine that fall into this category. Also I addressed the potential of utilizing hydraulics and they are not applicable in these circumstances for reasons that I have stated. Unless you are aware of and can provide a 'hydraulic solution' that does not require the cylinders &/or rods sticking out from both ends of the CVT, it is not feasible. If you are addressing the idea of utilizing hydraulic pressure to power the motor to move the linear actuator in place of a 'off the shelf' stepper motor or linear actuators that already have the required positioning sensing and accuracy built into them, there are significant obstacles to overcome this design including the significant additional costs involved to implement such a design. As you pointed out, utilizing engine hydraulic pressure would require the utilization of an expensive valve body and spools to provide for movement in both directions. Also the required positioning , feedback and correctional adjustments required for this to operate effectively would be a much higher cost that one that uses a stepper motor or a linear actuator. Even if it requires stepping up the voltage to 24 VDC for the stepper motor, it will still be significantly lower cost and the development cycle will be much shorter than an effective precision hydraulic positioning, feedback and correction system. The forces required to move the shifter mechanism are quite low and does not require the power density that hydraulics can fulfill and justifies there inclusion to meet these needs which are nonexistent in this application.

Also hydraulics per say tend to be quite expensive though this is a very basic system that requires very little complexity for a hydraulic application. Auto manufacturers are VERY 'cost conscious' and every dollar added to the cost of a product such as this for mass market transportation, as opposed to and industrial applications where the product may be used and have to withstand 10s to 1000s of times longer life/MTBF that justifies such added expenses.

Re: Sharing the wealth.

This will depend on circumstances. If the solution that I require is a new invention in and of itself than I would expect that its inventor will patent it themselves as I will not be the inventor of it even though I may utilize it. Also my invention is the CVT mechanism per say and not the stepper motor / linear actuator, sensing and correctional feedback mechanisms. These are all readily available mature technologies.

If it is a commercial product that is readily available and it is utilized in this product then the supplier will get his profits from the sale of the components.

If you have read all of my postings you will see that I wish to license the technology far and wide and have no interest in establishing manufacturing capabilities for this CVT except perhaps for small quantities required for prospective clients to evaluate my CVT. Frankly even this will likely be unnecessary as there engineering departments will be able to ascertain the viability of the product just from the design details. However the field of inventions is littered with products that never made it into production because of 'The Devil in the Details'. It is not uncommon for things that the originators of such designs very quickly 'glossed over' as being a minor problem that is easily solved that turns out to be anything but. Thus a (crude) fabricated working demonstration prototype that prospective clients can readily see working properly in operation on an engine dynamometer that the technology works the way that I claim it does will be very valuable and will result in being able to license the technology at a much higher profit for me is significant. In such a scenario I would not undertake any logic R&D required but would just utilize a laptop computer to operate the prototypes/demonstration units. Once any (major) auto manufacturer utilizes my CVT in their production models the viability, veracity and credibility will be well established and will serve to add significant bargaining leverage during negotiations.

If your technology is included with the evaluation units then you will have your 'foot in the door' and hence an advantage over other prospective suppliers which you can pursue aggressively when companies license the technology from me. I have a number of such significant inventions and am looking for financing including collaborations and possibly Corporate (equity) partnerships. Though this invention will more than supply enough capital to underwrite other inventions, including the R&D and patenting, marketing and licensing of them.

I am currently researching direct liner actuators &/or positioning and correctional feedback systems for this CVT. If your firm has a solution to this aspect and perhaps other aspects of this CVT then I would expect them to supply the required products at their own expense as an investment for future returns. They would also have to underwrite their own required R&D specifics for this invention if needs be. Further (equity) positions may be possible with the injections of funding to pursue and complete this product and market it. I cannot and will not have any control over who the manufacturer utilizes for subsystems in this CVT including whether they make it in-house or outsource it.

If your firm is directly involved in integrating your technology for these subsystems including the required logic to operate it, you will be 'in the loop' whenever I license this technology with have detailed knowledge of the particulars of such agreements in including the timing of them. This is where your (aggressive) marketing will have its opportunity.

There are 2 approaches to this that I am considering: In both cases the technology and the mechanism will first be patented of course. I have done research on this and no such similar design exists. After that I can either just license this specific technology and the licensed clients will then have to develop it to the point where it is ready to implement and be included in their final products OR develop the entire package that the clients will basically just have to alter the physical specifications to utilize it in various products.

.

FYI: I am in favor of the first plan as I have numerous other (significant) inventions that I want to patent and license as well ASAP. Also the licensed firms are far better equipped and have the necessary resources and engineers to work out the 'fine details' and optimize the basic licensed CVT technology to suit their specific needs.

.

NB: This transmission has the power handling capabilities of being utilized effectively on large 5th wheel semi tailer tractor units, large buses and large heavy duty industrial machines.

.

Regards,

DougRH

Re: Aspiration Depression,

I assume you are referring to the vacuum generated on the suction stroke with the throttle being significantly closed on an 'auto' cycle 4 stroke engine?

If not please clarify this for me

There are a number of problems with using vaccum:

1 - the vacuum source is erratic and varies considerable and there is virtually none available as the throttle is opened up more. Even with a vacuum reservoir that is common place in cars will not assure the required constant availability. The nature of the CVT is that it allows the engine to operate in a much narrower power/speed/torque band where it has the best efficiency and the least pollution. Thus the CVT will be almost constantly 'shifting' gears' to accommodate this. This IS after all the factor that makes such a transmission so valuable and desirable.

2 - Most power brakes utilize a large vacuum diaphragm to assist with a and provide 'power brakes' and as such limits the vacuum available during those periods.

3 – Diesel engines to not inherently produce such a vacuum source though vacuum pumps are installed on some to overcome this very problem.

4 - Moisture/condensation build up and freezing further compound the complexity, cost and ineffectiveness of a vacuum powered system.

5 - A vacuum driven system has all of the inherent disadvantages of a hydraulic system that is further compounded by the significant compressibility of the power transmitting substance: highly compressible air.

All of the above factors make the utilization of vacuum power even less desirable than hydraulic power.

I DO appreciate your suggestions and input. If I still am missing the point and you have something entirely different in mind or have other insights, please do not hesitate to submit them in different terms so that I do understand clearly what you are suggesting.

Thanks,

DougRH

I read with great attention your answer which I consider very objective and going into the depth. I dare say that the best person to find a solution to your problem is your self since you master all problems and I doubt looking at your analysis that somebody will be able to give you a better solution than yourself.

I wish you luck and hope when the patent is applied for that you will inform us about the transmission since it really should be a very interesting idea to obtain a variable speed without a sliding zone at variable radii.

As far as I know and met variable drives they all are based on the transmission of the power via a elasto-hydrodynamic sliding area using either one or several zones in parallel depending on the torque magnitude. Some make use of a planetary gear with two entries. It seems that your idea is revolutionary and I shall be delighted when possible to know it.

Have a happy and successful new year!

Hi,

I thank you for your compliments (I think that is what they are (< 8).

You are correct in that this CVT does not rely on elasto-hydrodynamic forces as the power transmitting element. Though of course it does require and will utilize lubrication.

However my postings and questions here are specifically in regards to a suitable a self correcting precision linear mechanism which this CVT requires and has not been resolved as of yet.

You posted numerous questions for further information which I assumed was to assist yourself and others to further define and refine the requirements more accurately and specifically in order to provide suitable solutions to this problem, which I have supplied. But you have offered no suggestions or solutions to the actual query which is to find a suitable precision, self correcting linear actuator that is required in order for this CVT to operate correctly and successfully.

This is of course your prerogative to respond or not to respond to and suggest viable solutions to the actual query that I presented.

(8 >) Health, Happiness, Contentment and Prosperity to You and Yours in this New Year and Decade (< 8)

I read again, and please believe with great attention, what you wrote and allow myself to list it since you wrote that I did not make a suggestion: a-The 300°C are a very high value can it be reduced by a screen between exhaust and device? No. As before, the prototype is 'generic and thus I am designing it for the 'worst case scenario.' To this comment you get an answer with the copy of following indications in the presentation of the suggested device which confirms what I already wrote: "The AS5215 is a redundant, contactless rotary encoder sensor for accurate angular measurement over a full turn of 360° and over an extended ambient temperature of -40°C to +150°C." b-Basically NO rotational movement of the linear shifting mechanism is tolerable. c-1" ~ 2.5 cm in ~ 250 milliseconds at most (>0.1m/s) d- It will have to be ~ 12VDC e-I consider that you are a very skilled person due to the analyses you made and that you are also aware of it according to your answers as follows: I am fairly well versed in hydraulics I am very well versed with all of the existing solutions to this problem. this will likely be one of, if not the most cost effective transmissions ever built in the modern post industrial revolution. f-However the lead screw and the driven nut on the linear shifter mechanism also is prone to increased inaccuracies with wear and tear, and (self) correcting active feedback will be required regardless of the mechanism used with the most expensive option likely being that of a lead screw and driven nut. If you use a sensor for the position-an absolute sensor- then whichever the wear will be the screw turns as long as needed to reach the target position. Of course the backlash due to wear could generate some problems in start-stop situations. g-Regardless, this mechanism must retain, hold and prevent any movement of the linear shifter mechanism in all planes except in the back and forth plain that it is designed to travel on. h-Thus the power of the stepper motor and the possibility of slow &/or incorrect positioning due to extreme conditions such as very cold ambient temperatures and the resultant significantly higher lubricant viscosity that the linear shifter will have to overcome. On the other hand the high speed/very short time period movement's required can be more easily accommodated by a chain or cable arrangement than the lead screw arrangement. In fact you define what you want, so why try to get a solution if you have already a concept? i-As you pointed out, utilizing engine hydraulic pressure would require the utilization of an expensive valve body and spools to provide for movement in both directions. (I did not suggest HYDRAULICS but pneumatics and in the following comment I did mention that it will not be suitable due to time constant imposed) j - Most power brakes utilize a large vacuum diaphragm to assist with a and provide 'power brakes' and as such limits the vacuum available during those periods.(In brakes the forces are very high in comparison to the force you expect here you make an error of quantitative estimation but any way I discarded the pneumatic solution before your comment) Due to above content of your own text I wrote that you are the best to develop it. The suggestion I made is as follows and goes, for a recommendation, a guide line, quite far if you read it carefully "If I look at all the constrains you list I see in fact only one solution which is coherent with almost all of them but has to be analyzed in details: it is a special electrical linear actuator with integrated feedback and no backlash. This can be imagined working with DC current but requires, due to the imposed stroke, a special design and a microprocessor control which will consider the differences between the actual position and the target optimizing the force versus displacement profile in order to reach in the shortest time the target without overshot (for the analysis an estimation of the moving mass would be necessary not only for the force since the control has to consider the kinetic energy in the "slider" in the "braking" phase). This requires a non linear adaptive control possible to be made with a specific algorithm and variable control loop parameters." . If you expect to have a full solution presented it is better to go to a manufacturing company which CR4 is not and ask for a proposal. I have the feeling that you did not correctly understand what CR4 is. Here if you come with a problem or a solution and ask for an opinion or for help tenth of skilled persons will jump to support you. Look at the over 200 comments on the thread concerning water harvest from air it is a beautiful example how people can involve themselves. You came with a specification and expect a solution as you could obtain from a manufacturing company but not from a group of experts who will deal only with software and opinions. They will share their knowledge but not work for you. I can understand you from a company you get a solution only if you pay for in fact you expected a free solution but your specification is so tight that only a substantial effort could lead to a correct answer. As a further comment, if you do not have a variable component you are obliged to have a series of fixed transmissions which you shift when needed. This imposes the great accuracy in positioning. In fact with a system controller which tries to optimize the overall function it is not with a true variable drive to have a positioning accuracy since the controller moves the drive to the optimal point. I have the feeling that you are very familiar with open loop systems and do not apprehend all advantages of the closed loop. It is the case with machine tool which for some operations use open loops as for instance for the thread cutting. With modern centers it is possible to cut a tread (or mill it) only by programming and using the closed loops for feed and rotation. Of course the tool wear can be a problem reason for which many systems have an integrated sensor for control and adjustment. The step motors have a lot of advantages and it is good that you look at this solution but you should consider some aspects as: - With an important mass the risk of over shoot is real if the end speed is not small enough - If there is any force on the "slider" then it should be verified that the "stiffness" in stop position is big enough. - There is also a problem of maximal speed and the optimal dynamic profile for a stop on position. I would like to make a last remark related to temperature range. You want to go as high as 300°C(Celsius) which makes a difference of 280°C from the ambient at assembly. Assuming a dilatation coefficient (differential between sensor and support) of 1E-5/°C for a 250 mm length the shift will be of 0.7mm. Your maximal tolerated error is 0.005"=25.4*5/1000=0.127mm. The temperature influence is only 5.5x the maximal position tolerated error! This means that only for strokes of 45.3mm(1.78") the temperature influence will be equal to the maximal tolerated error, which does not give any reserve for the errors inherent to the positioning system itself. Somehow you will have to solve this problem. Wish you again good luck and a happy new year.

Hi,

I thank you for your detailed attention, time, feedback, suggestions and information.

When I stated that you had made no suggestions, but had only asked for further information and clarifications, I meant no disrespect or disparagement of you or your obviously very informed knowledge in such matters.

For clarification, I am not 'a company' but the proverbial struggling Inventor' whose health crashed very badly several years ago in many ways and now live in poverty. So I do not have any such extensive resources as you may imagine that I might have.

For the record, I have not 'rejected' any input nor suggestions from anyone out of any sense of contrariness but only out of the knowledge of what is required and the conditions that the effective mechanism will have to operate in and under and that I am seeking an effective solution for.

From your specific detailed knowledge, obvious experience and usage of highly technical terms I have come to the conclusion that you are a trained Engineer. I may be wrong in this and opening myself to the error of 'making assumptions', but your input suggests otherwise. I have no such education, though I did embark on that particular path as a young adult. I was taken away from completion of these studies by circumstances beyond my control, as 'Life' is want to do. Indeed a great many of my significant current health problems stem from the same circumstances that did not allow me to finish those coarse of studies. I state these not as a plea for sympathy but only to acknowledge my own limitations in matters such as this were what I know and understand of such matters has come from experience &/or self taught knowledge and wisdom. These are factors in my life that are quite significant in this lifetime and extends to pretty much all fields of science, technologies, trades as well as the 'occult' or 'unseen' Spiritual aspects of life and existence that stands behind this one and as such this one only exists because of such 'unseen' things that are quite erroneously labeled as 'unknowable' by most peoples of 'advanced, technological' civilizations that are unable to meld and understand that the two are NOT mutually exclusive. There is no existence, except for the God(Head), regardless of what terms are used to describe it. I do not bring this up in order to start a debate over such things in this realm which this forum is not orientated towards, but only by way of explanation of my makeup, experience and knowledge. In this lifetime I have always been a voracious seeker of knowledge AND wisdom in virtually every aspect of existence and as such am primarily 'self taught' in a wide range of subjects. In regards to this specific matter, I am not sure how many of the input by others and my responses to them you have examined or if you have kept to your own specific input and advice. When I said that you had not suggested any solutions, but only posed (pertinent) questions; again it was with no disrespect or intended disparagement in any way, shape or form of you or anyone else here. I do understand and appreciate that I am soliciting and receiving 'free advice' as I to contribute to a variety of different forums in freely assisting others with what I can and am able to offer occasionally. If you have read the other postings on this matter, you will be aware of my intention not to become a manufacturer of my CVT design, but to license it. With this in mind, on the one hand theoretically I don't really have to concern myself with such details as I am undertaking to find a solution to it here as those that license it can provide design and implement these aspects of this CVT in any form that they deem suitable and advantageous. However the automotive field is notoriously difficult to 'breech' from the outside and most solutions are generated from within the realms of their own very broad and deep resources, knowledge, experience and organizations. So if I want to have even the remotest opportunity of succeeding with this venture, I DO need to present a fully functional package that I can demonstrate that it does indeed work and function well and properly and has the advantages that I put forth for it, even though the final production models may different significantly from my demonstration prototype.

As it is quite likely that you have discerned the distinction that I have made of this being a 'Continuously' Variable Transmission (CVT) and not and 'Infinitely Variable Transmission' (IVT) for any and all that do not understand nor appreciate the distinction, by CVY DOES have specific, fixed quantum 'gear ratios' as opposed to a IVT which does not and can operate at any and every 'gear ratio' within its range. Hence my need for very accurate placement and locating of very specific operating positions of the shifting mechanism that would not require such exacting placement of the 'shifting' mechanism as it can and does operate at any and every different gear ratios within its specified range so there is not the necessity for the exact locating of the shifter mechanism as the IVT will still function properly if it is off a little bit, whereas my CVT cannot and will not operate if the linear 'gear ratio' selecting mechanism is not in exactly the right place it will not select any of the fixed gear ratios at all and as such will only be in 'neutral' and not transmit any power at all; or even worse will cause very significant and substantial damage to it and even destroy it. You did effectively go through the specific operating requirements that I subsequently supplied and as I did ruled out numerous possible solutions because of the specifics of the requirements. I have some disagreement with the reason for ruling out pneumatics as 'not being fast' enough as this is an aspect of pneumatics where the compressibility lends it a fairly high 'springiness' and as such can and does have the capacity for VERY fast operation. As an example that confirms this I point to the Renault engines in Formula 1 racing in recent years where the valve train has been operated entirely by air pressure in a 4 stroke Auto Cycle internal combustion engine operating at speeds in excess of 19,000 Revs per minute! Even in passenger vehicles which operate at orders of magnitudes of forces lower than such very highly tuned and power and torque output of Formula 1 engines, it is typical for the valve train components to operate quite amazingly at and experience accelerations of up to 100 Gs routinely in the valve train for years of reliable and relatively trouble free operation.

As an aside, it is this very fact that led me to undertake extensive research to overcome this limitation primarily through the usage of my own practical knowledge and experience and utilizing 'thought experiments' very effectively that has led me to an outstanding design of a very elegant, simple, compact, effective and a very low cost solution with a very low part count for an Engine, pump and motor design that readily scales to ANY size. It is my plan and hopes to be successful with the implementation of this CVT that will allow me to embark on and implement this engine which is suitable both to hybrid vehicles, engines for a realistic 'flying car' as well as numerous other applications.

But I digress, your conclusion that my requirements are not the same as a very highly loaded, accelerated, high speed valve train in a racing engine with its 'fixed stops' that makes pneumatics highly effective there but not for this application are correct.

As I progress through this search and journey I am being led, as a number of others here have; to the fact that a 'pure' linear mechanism as opposed to a rotary to linear configuration is the most appropriate, realistic and advantageous solution to these design requirements.

I know very little about the specifics of this technology except for an understanding of the basic and underlying principles that they operate by. One example that comes to mind as a possible solution from the machining industry where CNC equipment as well as manual machines that are retrofitted to install precision digital readouts may hold some promise. Though they are not routinely subjected to the temperature extremes including a very hot lubricant, they most certainly are in continuous proximity of varying sizes of ferrous metals that does not inhibit there continuous and realizable accuracy. I am not familiar with the principals that they operate by, but will be researching it as well as examining other pure linear solutions. I am wanting to reframe and pose the question from a pure linear actuator solution but without abusing the privileges of this excellent forum. I am not well enough versed in the protocol of this forum to know what and how this is can be done without it being considered to being inappropriate.

Once more I want to thank yourself and everyone else for their detailed analysis and input to this very exacting problem.

(8 >) . A Happy, Healthy and Prosperous New Year to One and All . (< 8)

.

PS: That is a very attractive flag, may I ask what nation it represents?

As it is quite likely that you have discerned the distinction that I have made of this being a 'Continuously' Variable Transmission (CVT) and not and 'Infinitely Variable Transmission' (IVT) for any and all that do not understand nor appreciate the distinction, by CVY DOES have specific, fixed quantum 'gear ratios' as opposed to a IVT which does not and can operate at any and every 'gear ratio' within its range.

I note that your usage here is a little out of the mainstream. The "continuously" in CVT means that the ratios are not "discrete," so a typical CVT has an infinite number of ratios between its lowest and highest. An IVT, however, supports a special condition in which there can be input rotation without output rotation, so that, at a standstill, the ratio itself (in addition to the number of ratios) can be infinite: e.g., 1000 rpm input, 0 rpm output.) (Some hydrostatic lawn tractors have this characteristic, and can, for example, hold a speed of zero on a hill without the use of brakes.) (Most IVTs include reverse gearing as well as an infinite ratio gear -- and usually do so by the intrinsic nature of the gearing system. This is unlike a CVT, in which reversing is handled as it is with a manual gearbox, by interposing an additional gear and shaft in the series.)

The most basic CVT is, of course, the snowmobile type (seen in even simpler form on some machine tools) in which the change in ratio is continuous (stepless) and in which the number of available ratios is infinite (within a finite range).

The Wikipedia article on CVTs includes a section on IVTs which correctly makes this distinction. (The terminology, as it is generally used, is not particularly clear: both CVTs and IVTs are infinitely variable. But such is language: after all, we have jumbo shrimp.)

Hi ,

While I agree with you about the capacities of some small lawn and garden tractors. These utilize a Hydrostatic 'gearing arrangement' that utilizes hydraulics to change the apparent 'torque/gear ratios'.

However I disagree with you about your terminology. As it is applied to the automotive context and transmissions, which is the intended primary market for, this Continuously Variable Transmission (CVT) design is NOT an Infinitely Variable Transmission (IVT) and does in fact have many set, fixed, discrete quantum gear ratios, albeit the fact that it has many more than most automotive transmissions in use today. My CVT does not, and is not capable of operating at thousands of very minute different 'gear ratios' as a true IVT is; even though my CVT is more readily adaptable to a much larger number of specific gear ratios over a much wider range.

While I agree with you about the capacities of some small lawn and garden tractors. These utilize a Hydrostatic 'gearing arrangement' that utilizes hydraulics to change the apparent 'torque/gear ratios'.

True, with most. However the ToroTrack (which is branded Infinitrak for lawn tractors) is an IVT, with "geared neutral" in their terms. This provides an infinite number of ratios from fast forward to fast reverse (and in use, you would hardly know it is not hydrostatic) but the linkage is mechanical, via friction.

While I understand that your particular "CVT" is discontinuously rather than continuously variable, that is not the case with the standard CVTs that have been in use in automobiles for many decades, (with mass production starting with the DAF unit). Although many modern CVT's allow a mode in which discrete ratios are selectable, all the production units inherently provide an infinite number of ratios, but are not called IVTs. IVT, instead, has been reserved for those which are like the Torotrack, which is available in IVT and CVT versions, both of which provide stepless ratio change. The Torotrack site shows how the terminology is now used in the automotive industry. The terminology is not "mine," and it is not all that logical, (because there are an infinite number of ratios available in a traditional CVT even if the range is from 2:1 to 1:1) but it is widely accepted.

Sorry, Doug,

Blink is right, with the terminology. Note that some CVT's have purposely induced 'rests'. That means, taking Honda as an example, in the Fit, that there are 7 set rests in the otherwise totally constantly, and infinitely, variable "Van Doorn" transmission. Gives a "7 speed CVT". If yours has a multitude of set ratios (does it?) then it's possibly better described as a constantly changing /shifting transmission. Oh, I don't know!!!

BTW in an earlier post ( I came late to this one and am 'skimming it) you mentioned that Renault F1 engines have a high horsepower and torque. They have damn all torque, that's why they have to rev 'em to 19,000 rpm.

Interestingly, the original Paris - Marseille race featured a 13litre vee twin Panhard which revved out to 1200rpm. That did have torque.

Cheers,

Stu

Fixed vs infinite gear ratios. Torque: Otto vs Diesels.

Hi Stu,

There are definitely different connotations of 'CVT' used to be sure. Regardless of what the terminology is, mine most definitely is not a infinitely variable transmission; it has fixed, specific gear ratios. I keep looking for another term other than 'gear ratios' as the only gears in mine are idlers for reverse. But everyone understands and relates to 'gear ratios' immediately. I think that using the terms 'mechanical advantage' would probably be more apt.

F1's: it's why they have as many gear ratios as they do.

Likewise I would think that like most very highly tuned engine that they are quite 'peaky' and have a quite narrow bandwidth that they have any real power in.

But I still remember Michael Schumacher winning an F1 race in which he only had third gear for most it! Quit telling that.

Diesels inherently have a much flatter and higher torque curve. Unlike Otto engines, the torque curve tends to follow the revs curve much closer than Otto engines do. It's one of reasons that they use them for heavy hauling. Diesels are inherently considerably more efficient as well and produce much more torque than the Otto does.

Regards,

Doug

Why not use "transmission ratio" ? I t is correct from the physical point of view since you transmit via which ever system the power from inlet to outlet and you have a transmission ration -i.e. a ratio between speed or torque inlet to outlet- which is variable even if only in steps.

This way nobody can say you want to give a wrong information.

The term could thus be : "variable ratio transmission" = VRT

Nickname

That is a good ides thank you.

I haven't forgotten about your last lengthy posting and I WILL respond to.

As I was reading this thread over again from the start, I realized that I forgot something very important in my requirements that I started off with. The shifter mechanism will be fairly heave 5# ~ 2 Kilograms.

Did you find a nickname that you like yet?

Lately I have been thinking : 'Rocket Scientist' But I don't think that is a very good idea.

Reduction ratio?

Hi Garth,

That is certainly one possibility.

it would be more apt than 'mechanical advantage' that people would not immediately relate to and understand in this context.

Or if the context was not stated, then they wouldn't relate it to being a transmission.

Hey DouRHg,

Last F1 car I cum 'cross had 7 for-wad an 1 rev-ass.

Last IC truck I cum 'cross had 5 gate rod-ranger + 2 spud diff.

Thar be 20 '4-wad gears' - and thar's the simple âm đạo.

So "connotation" wise - where U at dougal shoewanker?

"Mor Talk"? - U neber heard of de udderquare petrol injine neiver - has ya?

But luck 4 U, No Name hear 2 putt U strait on hou 2 say tings.

<an som upstart nick yor ∞, U no dat?>

<"Quit telling that".>

I suggest that when you see that is a posting by me that you completely disregard and ignore it as the totally and completely meaningless insignificant trash that it is 'guest'.

Oh - I don't know if "Garbage In Garbage Out" is fair Doug.

Guest has pointed out that F1 generally have 7 gears - which, if I may add, covers the range of 0 to around 200 mph (300 km/hr for metric)

A CI truck has 10, 15, 20, some 25 ratios to cover 0 to about 80 mph, maybe 100 on a good flat stretch.

So Otto uses 1 ratio per 28.5 mph and CI uses 1 ratio per 10 at best, to 4 mph.

It would seem what ever point you were making in terms of torque curves is undone by by your own assertions on numbers of ratios - as you "factored out" the relative velocity envelopes involved.

Now you may not like it - but an "idiot" has exposed that "omission'.

Humility rather than arrogant abuse would seem in order.

"CI" Doug is "Compression Ignition"

How could any one involved in engines above level 101/day one, not know that?

You Sir are a scoundrel, a pretender and a scalawag

To think I have tried to help you and you spit in my face!

Lyzine - indeed - petty, recalcitrant, rude and grossly ignorant to boot.

I would not be surprised if the Forum as a Whole granted your wish

Mass & De/Acceleration

Hi RS,

I'm glad that at least someone is 'enjoying the 'show'' (< 8)

No worries, I've been preoccupied with other matters and am going to be very busy with other things for the next little while.

The distance between transmission ratio changes is quite short ~ 3cm. But it will still have to be done very quickly without overshooting and having to make subsequent correctional movements.

I still intend on using detents and spring loaded positioners but will likely require more than just that for accurate positioning now. As I was thinking about your suggestion of the 'off the shelf' spring loaded ball bearing detents as opposed to small spring loaded rods with a hemispherical end on them that I was attracted to this alternative because they would be seated deeper into a rounded groove or spot of the same diameter and thus position it with more accurately with more reliable repeatability. This would be the case, but it also means that it will require more power to get them out of the holes to move it again as well as significantly increasing the wear rate.

So I re-examined the options of using a 90 degree (2x45) slot for the positioning placements as it has more of a smoother slope to move it out of them though it won't position it as positively and accurately. As with most things, especially in such mechanisms finding the best 'balance and mix of tradeoffs' is key. This will require more accurate machining, but then that is standard with machining anyway. I agree that regardless of what the actual sliding mechanism, dovetail joint, gibs etc that unless the stepper motor is VERY large with a heavy current draw it will be unsuitable for the job. Another problem with using a stepper motor is that the resolution and the spacing of the individual positions has to match the resultant linear movement. Of course this can and would require utilizing a driven pulley of the right diameter to accommodate this. Its close enough to being almost constantly in motion that it requires a 100% duty cycle. Again there are the environmental factors: very hot in summers to start with plus the heat of the engine and exhaust system etc. In winter starting up the lubricant will be quite thick and thus likewise put more load on the shifter motor. Fine metallic particles in the lubricant etc, etc.

Again a suitable 'off the shelf ' solution would be nice, but everything that I have looked into is both to large and too expensive. I have been informed that even the ground, hardened lead screw with a 'ball bearing nut' will have problems of overshooting from momentum all by itself, let alone with 2 kilos attached to it. Not all of the mass is positioned right on the actual traveling shifter block either. Significant portions of it extend out quite a way away from the mounting block and thus the 'leverage' and the resulting force vectors in both de/acceleration that will exaggerate and amplify this and has to be taken into account.

Thus the mechanical advantage that a lead screw would bring to this application is a positive point, but there are numerous factors against it.

As I said, I'm going to go back through the entire thread and re-read it all and study and cogitate it again, making notes and keeping ALL of these factors in mind. I'll start with having the specs out to refer to constantly

As always, thanks for your participation and contributions.

Have a 'better one'

Doug

Hi Stu,

I do understand and you are correct.

I'm a lousy speller.

A worse typist.

Verbose.

Likewise I am not good at composition. The longer ones are quite a laborious ordeal for me.

But I say what I mean to, even if it is of broader scope than most &/or goes into more details, social impact and responsibility etc.

The 'time' aspect is certainly apt as well. Management of it is certainly not my strong suit.

You will find some quite short, succinct postings here by me as well though.

I do address some things that are more of a general nature and not always related to the a specific issue. I do because I think they are important. What good is all this 'advance technology and science going to do it most of the life on our planet including us is all going to be gone in a couple of centuries because of us. Hardly a trivial issue and alas as much as most people want to live in denial of it, nevertheless it IS the case and hardly trivial.

Part of the reason that we are in this very rapid 'death spiral' is because of the millions 'very smart' people that we now have that could and did create numerous things without any thought or concern over their broader impact and just carried long merrily as if they were all in a vacuum. We ARE in a position where we can't just keep creating more and more 'neat things' just for their sake alone. Our world is literally dying for want of wisdom to guide and temper the power that impact of all this science and technology. We can no longer afford for people creating these things to be totally unconcerned about it and have no social consciousness about it.

If professionals, scientists, engineers and other 'armature technologists' like myself don't carry out their tasks with this broader view in mind and take it into account and act accordingly, we have no hope whatsoever.

These are hardly 'trivial matters.

Everyone on our planet should be on a very focused 'war time footing/ operational mode.' We are ALL in a situation that mankind has never been anywhere even close to what our current situation is. Because of this it is very likely we ever will again because the world isn't responding as is needed.

One of the short comings of Democracy is that the people that are in power have to win a 'popularity contest' every 4 or 5 years. it makes any long term planning very difficult, especially with the communications technology we have now. They don't even have the opportunity to really even have their 'term in office' secured as they won't be around that long unless they keep just do what makes the masses happy RIGHT NOW and maintain and even improve the status quo. Most are 'governing', if you can even call it that, in the 'not on my watch' mode.

There are numerous cases of light social communications on here, which is a good thing even if it is 'Off topic'.

One of the people that is and 'old hand' at this made the valid point with me that if one is adding such postings, to mark it as 'off topic' in the first place; which is a good idea and I have been trying to remember and be frank and honest and do so when it is appropriate.

One of the nice features of this venue is that opportunity for everyone to 'vote' as opposed to the relevance &/or importance of the postings. I believe that this has more importance than most people think it does.

With life 'being school' I most certainly have my challenges to face and work at and through and hopefully overcome at some point in time at some stage of existence just like everyone else does.

So you tell me: were the few minutes and the ~ 1 KB of storage space that I used addressing this matter a total and complete waste and as such should be expunged or even better yet shouldn't have been done in the first place ?

But I don't reject or refute your observations Stu, as they all hit the mark and as such I welcome and thank you for them.

All the best to you Stu,

Regards,

Doug

Hi,

1-To your question it is the flag of the European Community.

2- The linear actuators are AC for long strokes

3- It is possible to use a "metallic belt" in stead of chains and come to a quite low cost system with a DC motor and a linear displacement transducer as you have met in the retrofitting of machine tools. This approach would be the most economical with the belt on 2 wheels: one a sprocket and one a return wheel. A tension could be introduced with a spring. High quality steel belts are available. By EBW it is possible to make a closed loop and with help of laser the windows for the sprocket teeth can be cut.

Stiffness will be high, wear will be zero and cost very low it could work at 300°C and if the wheels are of the right radius there will be no fatigue risk so that you could expect, at least for this part, a high MTBF. The problem as was already mentioned will be the motor. If brush-less the hall sensors will not resist to 300°C and the coils will have a very low life expectancy.

Now you have a suggestion as you expect.

It worked as I told you: come with a proposal it will be criticised the right way and if you like the results then you use it.

Critics should not be only negative but also constructive.

Best wishes for success.

Hi ,

Thanks for the information and suggestions. Your design recommendations are in line with some that others and I myself have come up with and made. If the motor is rotary it can and will be mounted externally and any auto manufacturer with any decent design teams will keep the hot exhaust away from the motor significantly reducing the heat problems and as suggested further shielding to protect it from both heat and mechanical damage if it is exposed to road hazards if located at the bottom CVT and of the vehicle.

If I end up utilizing a rotary to linear arrangement as opposed to a purely linear one, I do have concerns of temperature related extension and contraction of whatever element is used to impart the rotary motion to the positioning of the shifter mechanism. To this end if at all possible I am striving for and will give implantation of the positioning sensor being on the actual sliding shifter mechanism to ensure the accuracy of this the highest priority. This is THE most important design consideration of this specific aspect of this subsystem and the CVT's success or failure will be significantly influenced by the successful implementation of this aspect of this CVT.

As you and others have correctly pointed out, true critical analysis with both depth and breadth addressing all possible aspects are crucial to success and I appreciate such scrutiny, pertinent questions, observations, conclusions, objections, feedback and suggestions that like yourself, many have significantly contributed to.

You have all been very gracious and generous with your time and analysis and as one who is not a professional I am very appreciative of ALL of it! (< 8)

Hi,

In spite of my initial posting referring to a rotary to linear mechanism, like yourself I have come to the same conclusion and if at all possible I would prefer to find a (cost) effective purely linear solution for this application. To that end I have expanded my research into such devices and mechanisms.

The issue of routing external wiring connections to the Linear petitioner are readily overcome by attention to the routing of this wiring relative to keeping it away from (very) hot components such as exhaust passages.

I addressed the issue of the required logic controls in the two main options that I may utilize in marketing this CVT and it being evaluated by prospective clients. As I have stated, I have no wish to become a manufacturer of this CVT, put in licensing it. For demonstration and evalutation purposes I will utilize a LapTop computer to operate and control the CVT during testing on an engine dynamometer.

When implemented by a manufacturer, I will supply them with the various required operating and control parameters and they will design and implement their own logic solutions in that manner that is the most advantageous to them

(8 >) Health, Happiness, Contentment and Prosperity to You and Yours in this New Year and Decade (< 8)

Some automobiles, (nissan?) use a CVT.Check out how they do it as a starting point for your project.Not sure if it fits your needs or not, but why reinvent the wheel if it does?

I am very well versed with all of the existing solutions to this problem. A IVT/CVT has long been a 'Holy Grail' of the automotive industry because of the very wide and mutually exclusive requirements of high efficiency with minimum pollution over a very wide speed and power range which is rarely found in any other field. Most of the current solutions rely on friction as the power transmitting elements such as is found on snowmobiles with their two complimentary adjustable diameter pulleys using a very heavy duty V belt. This even includes one by Leonardo da Vinci. This reliance on utilizing a friction element to transmit the power is greatly limiting as to how much it can effectively work with and withstand. Without my CVT for the foreseeable future for this reason will limit the significant advantages of a IVT/CVT to very light weight vehicles. Audi (I believe it is) has a fairly complex and expensive configuration that basically puts a variable speed electric motor between the input and output stages. My CVT does not utilize any friction elements except perhaps for the 'clutch' mechanism which is not strictly part of the CVT per say. It is readily expandable to significantly increase the number of available 'gear ratios' &/or the power handling capacity utilizing identical elements as in the 'basic model' Except perhaps for the dual complimentary variable diameter V belt pulleys with their very limited load handling capacity; this will likely be one of, if not the most cost effective transmissions ever built in the modern post industrial revolution.

Hi Doug

Have you thought about a Linear Servomotor like this one?

Do you really need such an extremely tight specification for this linear actuator? It might just present some serious design and manufacturing challenges and also bump up the cost of your CVT to a level that is makes it unacceptable to industry.

Brgds

I am prototyping a vehicle which uses CVTs, mainly in the interests of mechanical simplicity, low parts count, low cost, and operating simplicity. The vehicle would be equally efficient with four or five discrete ratios, but shifting those ratios smoothly would entail the use of a clutch (which would otherwise be unnecessary, given the electric drive motors used in this vehicle), or careful gear unloading and speed matching on the part of the operator (as done, for example, in motorcycle racing, where the clutch is often not used during shifts), or by a moderately complex automated system for shifting (that would emulate a skilled operator shifting without clutching).

With a (standard belt style) CVT, the shifting can be easily automated in a simple mechanical way (as used in snowmobiles) or could be done with a simple slow-fast lever (like those on hydrostatic lawn tractors). I might be interested in your CVT, however. So let me play devil's advocate.

You are entering a market that is very mature, and quite competitive. I just rented a Kia Forte, an economy car, in LA. The transmission was flawless, always selecting the correct speed in ordinary driving, and with a nice +/- manual override to make it a manumatic, which was an advantage in the mountains. In cruise, the converter is locked up, and the transmission is as efficient as a manual. There was nothing in my experience with this econocar that would lead me to think that this car needed a "better" transmission. (This level of transmission was limited to near-luxury sporty cars about a decade ago). How would yours be better?

I have not driven one of the double-clutch manumatics (as used on Porsches, etc), but the reporst are that these work extremely well, beating 6- and 7-speed manual-transmission cars around race tracks. The new Honda 1200 motorcycle uses this type of transmission for its manumatic. How would yours be better?

Nissan makes a sophisticated CVT that can shift in either continuous mode or step mode. How would yours be better?

One of my concerns would be with the high level of precision required. For example, at the simple end of the spectrum, the CVTs currently on my vehicle could be shifted by an external linear actuator, and I could be off on positioning by a full millimeter (.040") or two or three (.120) and nothing would measurably suffer. If a small error can lead to gearbox failure, as you have said, then the control costs are inevitably going to be high to gain both high precision and high reliability. How will you overcome the controls cost issues?

Will materials cost be low? Can you (as in a snowmobile style CVT) avoid having to uses the expensive alloys, precise machining, and heat treatments used in a geared transmission?

Will you be able to use tooling already used for manufacturing existing transmissions, or will new tooling be required?

On my desk, I have a shift dog from a transmission used in a Mazda race car. The transmission was $50,000, and is pretty simple, and works well in racing (during which it is usually shifted without clutching, just like a racing motorcycle often is). The transmission is functionally equivalent to a manual transmission which can be manufactured for about 1/100 the cost (but this is a low-volume transmission). Could a manufacturer ramp up to the production volumes required to make the transmission viable: in other words, is there a compelling reason for e.g., Kia to tool up for your transmission, when the one in my rental worked so well, and costs so little?

I offer these not so much as questions that you must answer here, but as food for thought, and as preparation for the questions that will be asked as you market your idea. If you have not already done so, putting together a business plan and seeking funding can be a good first step. This process will help you focus on marketability and can help put you in touch with people who may have influence in the industry. Without a sound business plan, you can end up spending a lot in patent costs, only to find that you can't get your design into production.

... All of which may sound negative, but is not intended to be. We are in similar boats, working on launching new ideas, and I have found that it is helpful to have people ask potentially uncomfortable questions, so you are better prepared to overcome objections. I wish you the best of luck with your project.

Hi MauriceS, Blinky et al,

I agree with you entirely in regards to the importance of manufacturing costs. I DO tend to over engineer everything (a common term has even been adapted and utilized as an acronym to my tendencies in this area and over engineering and design methodology) and I concur with you and others about the importance of cost effectiveness. In one posting I state that 'it is notoriously hard to break into the automotive manufacturing field from outside the industry and that they are by necessity VERY cost conscious. I also state that with perhaps the exception of the dual variable diameter HD V belt pulley system utilized in snow mobiles and adapted for light automobiles, that this transmission with it's very low part count and simplified machining requirements it will likely be the most economical transmission ever designed and built in the modern post industrial revolution era.

Most auto manufactures design their vehicles to last 2,000 ~ 4,000 hours, which my transmission is more than capable of achieving very cost effectively. As I have stated, it DOES have the kind of load capacity and durability to be utilized in both heavy duty, very long life tractor trailer, large long haul buses and industrial equipment. Like my Engine design which only has a few major parts for a four cylinder engine and is scalable to ANY size, and a VERY high power to weight ratio likewise pretty well only utilizes currently available technology and will likely only cost 25% ~ 50% of the manufacturing costs of current Internal Combustion engines; and is also a serious contender to make a 'flying car' a reality! I could take anyone that has no prior mechanical experience but is interested in learning how to service and rebuild both this CVT and my Engine, that within a week they could easily be completely rebuilding either of these devices at a rate of at least 2 a day.

Very serious and important questions that I am very cognoscente of have been raised both in regards to the capital requirements of re-tooling, developing new technologies both for manufacturing these device and the components that make them. The answer to all of these questions is NO. All are capable of being built with existing manufacturing technologies and in the case of the engine, modification of one particular technology that will make for a dramatic increase in efficiency of any 'Auto' IC engine that it is applied to: either my revolutionary engine, or existing ones and even perhaps aftermarket retrofits. My engine will work very well without it, but as stated, an adaptation of an existing technology will make any Auto IC engine significantly more efficient. I along with a number of others here have suggested that a standard, mature off the shelf solution of a pure linear actuator or servo motor such as you suggest will be more than adequate for the job. The forces involved and required are very low, though as one person accurately pointed out, the mass of the actuator versus the element being moved will have an impact on this. With the self centering alignment assistance that I plan to engineer into this, a tolerance of ~ ±0.010" should be more than sufficient, which is not that tight of a tolerance to achieve with modern technology.

However I disagree with you about your terminology. As it is applied to the automotive context and transmissions, which is the intended primary market for, this Continuously Variable Transmission (CVT) design is NOT an Infinitely Variable Transmission (IVT) and does in fact have many set, fixed, discrete quantum gear ratios, albeit the fact that it has many more than most automotive transmissions in use today. My CVT does not, and is not capable of operating at thousands of very minute different 'gear ratios' as a true IVT is; even though my CVT is much more readily adaptable to a much larger number of specific gear ratios over a much wider range.

Out of essential changes in the most efficient and effective utilization of resources with the minimum of pollutants is by necessity changing the ethos of personal automobile manufacturing very rapidly. As mentioned very early in this thread, the extremely wide range of speeds and loads that are required for power sources in the field of automotives is rarely encountered by a very wide margin in any other fields. This is a factor that most that are not knowledgeable in this matter are likely to understand the importance of and will greatly underestimate it. These requirements are quite contrary to the desirability of maximum efficiency with the minimum of pollutants. Consider the following: In most first and even 2nd generation hybrid vehicles, instead of having an Infernal Combustion engine driving the vehicle directly, the vehicle is powered by electric motor(s) that run off of batteries and the IC engine ONLY runs to operate an alternator and charge the batteries only when they are in need of it. This is a very substantial increase in complexity and cost and with an inevitable loss of efficiency at each and every stage of converting any form of energy from one stage to the next. So why is all of this considerable complexity and expense utilized? It is because when the IC engine has to operate, it only runs in a very narrow speed and load range as is the case with most commercial and industrial applications where it runs at a significantly higher overall efficiency with the much less pollutants. A transmission with a very wide range and many more gear ratios allows the IC engine to operate directly within this optimum power band with the minimum of pollutants by changing the gear ratios much more often to keep the engine running in this optimal range. Where you current vehicle transmission has between 3 ~ 6 gear ratios with quite a large difference between each one that requires the engine to operate in ranges where it is nowhere near as efficient and cause much more pollutants. My transmission will give automobiles and smaller trucks etc 3 ~ 6 DOZEN very closely spaced gear ratios with a much wider overall range that will allow the IC engine to operate at its optimal efficiency almost all of the time. Likewise heavy duty commercial & industrial vehicles that currently have 16 gears can have over a hundred different closely spaced gear ratios with a much higher range as well.

FYI: Large modern day railroad locomotives run with this type of a 'hybrid' power train and have for some time with good reason and for the same reasons. The diesel engine runs within a much narrower and more efficient power band and powers a large heavy duty alternator that then powers electric motors that power the train.

Diesel engines are also significantly more efficient than the 4 or 2 stroke 'Otto cycle' IC engine that utilizes a spark plug to ignite the explosive mixture which a diesel engine does not do. Unlike an 'Otto cycle' engine, there is no throttle valve that causes the pistons to work harder to pull the new fuel & air mixture into the cylinder while a Diesel engine has no such 'intake throttle' so does not have to work against the suction by trying to pull air into the cylinders past a valve that may be almost entirely closed and as such utilize and waste significant amounts of power in doing so. For these same reasons, a Diesel engine 'breaths' much more freely and efficiently and moves the used, hot spent exhaust gases out of the cylinder and does a better job of replacing it with a full amount of clean relatively cold air that is always available for the optimal production of power. Its power and torque output are governed only by the amount of fuel injected directly into the closed cylinder. Diesels also have significantly more torque or pulling power over a much wider portion of their operating range than Otto engines do. As well as not wasting any fuel by breathing while the valves or ports are open, the fuel also has more than 20% higher energy available than gasoline does for the same volume of fuel. This is because is a 'heavier, colder' fuel with more oil in it than the 'dryer' hotter'' gasoline, propane or natural gas does. This also give the fuel more lubricating qualities where gasoline has a tendency to 'wash the lubricating oil' off of the cylinder walls that lubricate the pistons and rings which also provide the sealing of the pistons and as such the wear rate for the pistons, rings and cylinder bores is considerably higher than a diesel which give the diesel engine a longer life with a higher effective efficiency rate for a longer portion of its life cycle. Also the pressure/time ratio of the ignited fuel varies significantly between these two types of engines. While they both take place very fast, a diesels pressure does not rise nearly as fast inside of the cylinder as a gasoline engine does and thus the power is transmitted to the pistons down into the crankshaft at a significantly gentler rate. Though these pressure rises are VERY fast, they are a 'controlled burning rate' and are NOT 'instantaneous'. Older participants here may remember the milder form of detonation that caused pre-ignition that created the distinctive engine pinging sounds that accompanied them during periods of heavy loads and acceleration especially in very hot weather. As stated this is a mild form of detonation which is an uncontrolled near instantaneous form of explosion where all of the air/fuel mixture explodes simultaneously rather than a controlled burning front which travels front the spark plug out to the periphery of the piston and cylinder walls. Such (extreme) detonation will very quickly destroy and Otto cycle engine. Imagine having the cylinder head off and pounding on the top of the piston at the top of its stroke as hard as you can with a sledge hammer. Now take into consideration that this extreme force may be generated at a rate of perhaps a hundred times per second. How long do you think it would last ? In those days, the best performance and most power that the IC engine could be tuned to by most people including mechanics that did not have the technology to do it otherwise, was obtained by taking the vehicle out, getting it very well warmed up and 'power time' it by advancing the ignition timing until it just started to ping under the heaviest loads such as heavy acceleration &/or up a steep hill and then backing the timing off just slightly so that it did not ping anymore.

This also makes for a significantly lowered wear rate of the 'bottom end': the piston rods and crankshaft. Add to this the fact that the diesel engine has a much flatter torque and power curve and develops significantly more of both at a much lower engine speed than a comparable Otto cycle engine does. This also gives rise to a higher efficiency as the hot expanding gases have more time to push on the pistons and transfer the power through them down to the crankshaft before the hot, spent exhaust gases or released from doing their work in the cylinders and the lower operating speed of the diesel also further reduces the engine wear.

About 1/3 of new personal automobiles sales in Europe are now Diesel engines. The Europeans adopted a lowered allowable sulfur content allowed in Diesel fuel long before the north American market. Though the Sulfur is an excellent 'extreme high pressure lubricant' that primarily benefits the valve (seats) it is also the smelliest element in the exhaust that gives the Diesel it well known and deserved 'stinky' reputation. (The same applies to the 'lead' that used to be in much higher concentrations in IC gasoline, etc engines.) Newer generations of cleaner Diesel engines operating with lower sulfur fuels have no such smells and greatly lowered amounts of detrimental sulfur dioxide pollutants. Likewise they have nowhere near the loud distinctive 'diesel knocking' sound that the older ones did. Look to see more and more of these same generations of the newer cleaner, quieter diesel engines operating in north America, especially with the sulfur concentration in the diesel fuel being lowered as it is now. Coupled with my CVT, it only gets better! (< 8)

PS: Blinky: Many modern manual transmissions especially in motorcycles but also in cars with effective synchronous rings in good shape and properly adjusted are readily shifted without the use of a clutch by skilled drivers utilizing only the throttle once the vehicle is in motion. My CVT does require a very high duty cycle, high speed clutch due to the number of (automated) 'manual' gear changes used. To this end I am currently contemplating the usage of a 'band clutch', which are used in automatic transmissions and are found in industry primarily as 'band brakes'.

In most first and even 2nd generation hybrid vehicles, instead of having an Infernal Combustion engine driving the vehicle directly, the vehicle is powered by electric motor(s) that run off of batteries and the IC engine ONLY runs to operate an alternator and charge the batteries only when they are in need of it.

Actually, today this is not the situation. There are currently no series hybrids available from the major manufacturers: all, like the Prius (and other Toyota/Lexus hybrids), Honda Insight, Ford Escape, Nissan Altima, etc, etc, are parallel hybrids in which the engine can drive the wheels directly, and in which the electric motor can join in, or occasionally (and only at low speeds) drive the wheels through the transmission via a torque splitting arrangement. (The Honda is the exception here, with the electric motor operating directly on the engine flywheel, so it cannot drive the car solely on electric power at all -- if the electric motor is turning the engine is turning.)

The Chevy Volt will be the first production series hybrid, in which the engine is not (and can not be) connected directly to the drive wheels.

Only in a series hybrid can the engine loading be such that the engine runs at full load or not at all (and thus at optimum efficiency). In a Prius, the engine runs much of the time at low load (as when the car is cruising on a highway -- where it gets worse mileage than around town). In the Volt, the engine will operate only at high load, which has a strong advantage for around town, and a somewhat of a disadvantage on the highway, where the energy conversions can nearly cancel the efficiency peaking strategy.

My own prototype is a series hybrid (and like the Volt, plugs in for 40 mile range on electricity alone.) When it is cruising along at a constant speed, the engine starts and stops, keeping the batteries charged. (Going up a very long hill, the engine runs all the time.) The engine only runs at peak efficiency.

In my vehicle, (which coincidentally uses CVTs on the electric motors) mileage would suffer substantially if I used the simpler arrangement of an engine driving directly through CVT. The problem is that the engine cannot be heavily loaded most of the time with either a CVT or a multi-speed gearbox. Any existing engine has an ideal load and RPM, which can be seen on a BSFC map. In a general sense, the engine must operate at both its ideal rpm (typically around peak torque rpm) and its ideal load (typically full throttle torque at that ideal rpm). That has to translate into an ideal horsepower (typically the hp produced at the torque peak -- which is apt to be 65% of max hp) and no gear ratio can cause a car that only needs 15 hp to maintain 55 mph to run efficiency if its engine can produce 100 or 200 hp.

In the case of my own prototype, fuel efficiency doubles by virtue of running the engine only at near-peak load and optimum rpm, as compared to using a larger engine (required for the occasional required hp peaks) through a CVT with optimum ratios.

The differences in BSFC between cruise power and optimum power are very large, (2:1 - 3:1) and optimizing gearing does not solve that basic problem: change gearing to increase load, and you reduce engine speed from its optimum.

Your engine design may help solve this problem, without the need for running at both an optimum rpm and an optimum torque. (The Prius engine is quite good in this respect -- and diesels are also better than the typical petrol engine.)

PS: Blinky: Many modern manual transmissions especially in motorcycles but also in cars with effective synchronous rings in good shape and properly adjusted are readily shifted without the use of a clutch by skilled drivers utilizing only the throttle once the vehicle is in motion.

I do this fairly often, for fun... and used to do it all the time when racing motorcycles. The Mazda I mentioned has no synchronizers at all, and is shifted this way too -- in fact that is one reason I have a shift dog on my desk -- you can imagine that each improperly timed shift knocks the edges off the dogs. (This Mazda trans is just like an overgrown motorcycle transmission.)

Hi Blink,

Very interesting Blink. An excellent adaptation of sun & planetary gear sets.

I can see (significant) advantage and disadvantages in both transmissions in comparing the ToroTrak to my CVT

Thanks for the info, every bit counts and helps me to both get a realistic comparison as well as learning new (subtleties) on IVTs and CVTs

In regards to the description and defining terms and some of the differences and distinctions between between IVTs and CVTs, here is a direct quote from the ToroTrak WebSite:

"The IVT moves away from the constraints of stepped ratio automatic transmissions and unlike Continuously Variable Transmissions there is no torque limitation. The ratio range is provided not by a system of gears, as found in a conventional…."

Regards,

DougRH

Very interesting Blink. An excellent adaptation of sun & planetary gear sets.

It is a pretty neat system, which only works reliably because of the friction fluid/lubricant. The Torotrack system, because the ratios can be extremely high and very quickly changed, lends itself to flywheel storage systems. It is the transmission used in the Flybrid system for Formula One cars.

Just today, I received an email from SAE, which mentions that Carrero is has developed a proof-of-concept prototype around the Torotrack core.

Another CVT I've come across, which causes some head scratching, is one from Kertrain. They have prototyped incrementally variable and continuously variable transmissions that use non-circular gears. If you contact them, they can email you a brochure.

Hi Blinky,

First I hope you don't mind me taking liberties with your nickname. It is in no way intended to be denigrating in any way shape or form. However our names ARE a very personal things and we are beings of a very complex nature and most of our 'intelligence' is 'unconscious' rather than 'conscious'. Thus if it is irritating you in the slightest, please let me know and I will desist altering it. For me, using it in this manner has just the opposite effect on me, but it's your nickname and it's up to you.

I'm going through the entire thread and refreshing my memory and examining all information once more after some 'gestation period' and also responding to those that have been kind enough to persist in continuing to assist me with the subtleties and details of the specifics of this required mechanism.

+++++++++++++++++++++++++++++++++++++++++++++++++

ONE THING THAT IS QUITE RELEVANT AND THAT I REALIZE THAT I HAEVN'T PUT IT FORTH PROPERLY BECAUSE IT DOES HAVE A SIGNIFICANT IMPACT ON THIS IS THAT INSPITE OF THE FACT THAT THERE IS VERY LITTLE SIDE THRUST AND FORCE VECTOR ON THE SHIFTER MECHANISM IN OPERATION AS A REAULT OF ITS INTERACTION WITH THE MECHANISM THAT IT IS OPERATING ON AND VARYING THE GEAR RATIOS IS THAT IT DOES HAVE SIGNIFICANTLY MORE MASS/WEIGHT THAN MOST OTHER COMMON SHIFTER MECHANISMS IN MANUAL TRANSMISSIONS SUCH AS 'PICKEL FORKS' ETC!

++++++++++++++++++++++++++++++++++++++++++++++++++

I am purposely highlighting this in the hopes that it will catch other participants and contributors eyes as opposed to having to relay this information to each individual. I apologize to those that may find it irritating but I have done it quite consciously done it with good purpose and reason.

So finally onto my reason for responding to your entry # 43:

You requested specific information and disclosure on the specifics of my CVT design as it may be applicable to your endeavors. My apologies for my lack of attendance to this matter. I must admit that the prospects if this makes me VERY nervous!. Unlike my engine which came about 'relatively' quickly: 5 years of intense research and work and I have been 'sitting on it' for decades! (8 >( I know: MY BAD! )< 8) I have been working on this CVT for decades now! It is my very carefully calculated first important step that will hopefully finally set me on the path of action and to 'achieving my life's work' at this late date if I am fortunate enough to have enough time left to accomplish anything after squandering most of it on more mundane matters of Life.

I want to be VERY conscious and careful about this next statement as you have all contributed very graciously and generously and selflessly in assisting me in helping me to find the correct solution to this aspect of my CVT. I AM open to and willing and invite and WANT others to partner with me that can make a significant contribution with the prospects of very substantial rewards and hopefully likewise I will be able to assist them as well if they are in a similar position. Though It is my intention to bring others 'onboard' and participate with me in my journey, quest and contributions as well.

Thus I am open to such things and invite you to interact with me on this and we will see where it leads.

Looking at the Ker-Trains ReSearch devices that you posted the link for, they are definitely doing serious, thorough research in this field with some impressive results. Their clutch may provide a solution for my CVT. But if the 'watermark background' picture is indicative of it, then it will be too large and most definitely too expensive for my needs. It would appear that there primary market is for (very) heavy duty.

Most sincerely,

DougRH

Hi again Blink,

I understand the distinction you are making in the various configurations of hybrids and quite readily admit that I do not know the configuration off all makes and models and power train layouts and utilization in all hybrids available in the global market.

However this doesn't negate my knowledge and understating of the many different layouts and configurations of hybrids. Likewise I readily admit that I 'don't know what I 'don't know'' about ALL hybrid configurations. This venue continues to help expand my knowledge in these matters and fields./p]

Regards,

DougRH

Hi yet again Blink,

It sounds like you also have a very interesting project on the go and most defiantly are well ahead of me in this matter. It has me wondering many things about it, including the overall design layout and configuration, (carrying) capacity, efficiency estimates, (top) speed, weight etc. There are a lot of people, both the major automobile manufacturers and people like ourselves that are pursing significant increases in efficiency along with (significantly) reducing pollutants, both from improved efficiency with lower pollutants which in turn uses less fuel which in turn further reduces pollutants. I'd like to see some pictures and /or videos of it if you care to share them?

However I do not have the same 'route' mapped out that you do.

DougRH

Hi again Doug,

The website for my vehicle is here. The "woody" in the pics is the most recent version, although now the "wings" out to the fenders are enclosed, and the vehicle is drivable. (The red vehicle rendering is what a production version would like like.)

As often is the case, the concept works fine, but many little details crop up that need to be fixed. The CVT, for example, is generally OK, but has an odd condition in which it can hang up not engaged (i.e., with the belt loose). Then the motor has to be revved sky high to get engagement to occur -- and even then it can sometimes fail, because the rear pulleys are spread too far. Manual control (instead of the rpm vs torque balancing usually done) will cure this (I don't need or want the clutching effect that these CVTs have). As you may know, Hoffco Comet was the largest US supplier of these inexpensive (snowmobile style) CVTs. They have gone out of business.

Interestingly enough, in the production version, this manual control (which I will do by lever in the POC) will likely be automated -- so I too will be looking at linear actuators.

I'd like to know more about your transmission, because it sounds about ideal for my purposes. I'd be happy to sign an NDA. Perhaps you could shoot me an email through my website.

Re routes -- you're right, they are quite different. Mine has a narrow focus, and the intent is to fill a niche, using mostly existing technology and mass produced components, assembled in a way optimized for providing mainly commuter transportation at both very low operating cost and very low purchase price. Your route has much broader application, I think -- an obvious advantage... but that carries the corollary that there are big players to compete with. I hope both our approaches work well.

I've said it before I'm sure, but that is an really cool vehicle! GA.

Thanks Chris. It's always encouraging to hear, and most appreciated.

Ken, I just found out it was you. Great stuff. Stu.

Actually Blink my path and goal is almost exactly the same as yours. I have some very revolutionary ideas that will be significantly more efficient, but virtually everything I have come up with also utilizes existing technologies. Mine may differ in that they extend to some of the major motive components as well as the 'packaging'.

Mine also include utilizing the third dimension as well though and not just two which will make a HUGE impact and the gains made by it will be far outweighed by the decrease in the cost and resources required for transportation infrastructure. This is no 'pie in the sky fantasy' if you'll pardon the intended pun. There has been 'Going to be mass market personal airborne vehicles 'in the 'next 10 years'' for 50 years now! I have everything at my disposal to make it happen, except for the minor detail of the money! LoL (< 8)

Then: ________________________________________________!!!

Though I am considering founding a global consortium of participants of all types, levels, orientations, trades, professions, locations, corporate, private, financial, NGOs & GOs etc, etc.

I need to amend the first paragraph, as it may extend to an almost total and complete planetary shift in the production of power with virtually no pollution for ALL uses in a VERY short period of time: which is very good because VERY LITTLE TIME is all we have left to us now!

Everything already exists to achieve this as well. It will take more pure 'science' to manifest it, but I'm fairly certain I have this one nailed as well.

What is REALLY crucial is for me to manifest some significant improvements and efficiencies, which I am readily able to do; in order to establish some significant credibility on a wide scale to in order to manifest ALL of this which we are VERY sorely in need of in a VERY short period of time and I can facilitate it.

Do you see and understand the depths of the angst of my dilemma as well as the jeopardy that I am in ?

I hope you're going to become part of our community [CR4]

You've been a member & forgot about it in 06

You never actually told us how many possible positions there are?

Link to your new discussion

http://cr4.globalspec.com/thread/48512

Hi Garthh et al,

Thanks for the invitation. I have had significant health (and money) problems. Still have the health problems and then some, but I am working on the financial side of it both for my own personal needs and to try and get my 'life's work' done at this late stage of my life before my turn is up this time around. Like most sentient 'human' beings I have a deeply rooted impulse to 'contribute' and life on our planet is at a crisis point of a magnitude never before encountered and needs all of the help it can get. The period which the Dinosaurs along with 90% of the life forms on our lil mote in these vast cosmos died off took place over a period of about 250,000 years. That was so rapid and radical that scientists classify it as 'revolution' and not 'evolution'. So what is it now that the same thing is happening due to us 'highly intelligent beings' at an order of magnitude that makes the period that the dinosaurs and 90% of life dying off look like the 'Garden of Eden' in comparison. Regardless of if you take it from ~ 10,000 years ago with the advent of agriculture that allowed us to stay in one place and survive and advance our culture and society, or over the last couple of centuries since the industrial revolution. Either way we ARE IN the 'Apocolypse' and need all of the help we can get and I want to do my part before moving on again. If we are ever even noted on a geological or cosmological time scale, it will only be because of what a spectacular failure we were and perhaps as an outstanding example of 'How NOT to do it!"

As Carl Sagan stated: 'It is likely that 1/3 to 2/3 of the species that become sentient and unlock the secrets of Nature don't survive it. Either from completely poisoning the entire Eco Systems of their world as we have done, or through the incredibly powerful and potent weapons of mass destruction that they can and do build and in some cases use; or both.' Add the massive overpopulation such as we have into the mix. If it was any other species other than ourselves, we would all readily classify it for what it is: 'A blight of Biblical proportions' Alas we have our feet firmly and deeply mired in this category.

I am not a graphic artist, but have long had an 'editorial cartoon' in my head that goes like this: A scientist is standing with a white smock carrying and writing on a clip board, looking out the window and surrounded by banks of scientific equipment. 'Zoom out to the second box' and a similar scientist is standing beside the first one and looking down on our planet with oversized catastrophes drawn on and around all over the surface of our planet. 2nd scientist "How are the Primates doing Fred?" The 1st scientist looks over the top of his reading glasses directly into the 2nd one's eyes and says: 'It's not the monkeys man!"

The Genie is out the bottle, Pandora is out of her box and there is no way to put them back in. Our only hope is onward with considerably more caution and wisdom. One thing that is for sure: This IS a global phenomenon and we are ALL in it together. Reverting back to tribalism that has served us for many millenniums and is now also the source of much strife on what is truly now a 'Global Village' will most assuredly be the end of all of humanity along with most of the other life on our planet. The planet will survive us and life will likely continue. But if we are to have any chance whatsoever, we had better get our priorities in order, start ALL working together and acting on them towards the same goal or we are all kaput.

FYI: For those of you that may be interested in such things: I have never had any 'close encounters' but have personally had 3 'distant' ones that could NOT of been anything of 'terrestrial origin'. Nope, I'm not a crazed delusional crack pot. Life is inherent to our universe. Just try and not get anything to grow up in the cracks in your sidewalk. With the millions of variations of life forms just on our own lil mud ball alone, what are the odds that we ARE the only life forms in our ginnormous 'back yard'. Anybody that wants to give me odds against this bet, let me know and I'll take that bet as the odds are orders of magnitudes better than the lotteries. I am no gambler in any way shape or form, but the odds are most definitely on my side.

A couple of years ago, NASA succeeded in an extended scientific satellite mission that lasted several years. It's mission was to travel throughout our solar system carrying out a number of scientific experiments. One of its missions was to quite literally gather up some 'star dust' and return it to Earth which it did. Not surprisingly to me, it contained microscopic evidence of life. The aspect that surprised me: it contains NO DNA!

Things that make you go: 'Hmmmm!'?

Meanwhile, back down here on the ranch on terra firma: I have not stated the specific number of gear ratios as it quite readily varies widely and easily with very simple design changes. Also, the number of discrete gear ratios goes up significantly faster than the volume of this CVT does

In regards to the significant damage or destruction of this CVT due to malfunctions, like many (complex) mechanisms it just has to be designed, work properly and get the necessary maintenance and it will give long, reliable and trouble free service. Like my engine, a complete rebuild is very simple and quickly accomplished and requires much less critical knowledge, experience, inspections, measurements and analysis than almost every other transmission

The first working prototype will likely have ~ 100 gear ratios. Adding a whole other element/range compounds the number of available gear ratios and is readily accomplished with very little added complexity. Likewise to almost double the load capacity is also easily accommodated with the addition of further identical elements and a minor addition. All of these major elements utilized to achieve these can be identical to all of the other major components in this CVT. A definite plus for cost effectiveness.

. . . (8 >) Live long and Prosper (< 8)

Hi Doug,

It sounds as if you might enjoy Ken Wilbur's book "Theory of Everything."

Hi Blink et al,

I'm most definitely a 'Multi-Disciplinarian' with an interest and some knowledge of pretty well all of the Trades, Technologies, Sciences and Spirituality: the reality that lies behind, makes up and continues to sustain 'this one'. For anyone that is interested in a modern 'Scientific' body of knowledge of the latter, including its application to many aspects of modern life, I suggest that wWw.RudolfSteinerWeb.com, wWw.RSarchive.Org and wWw.Anthroposophy.Org are all excellent starting points. There is much related knowledge on the wWw as well as printed materials and ongoing active organizations based on (applying) this knowledge.

I'm primarily self taught in most things. I'm capable of doing pretty well all of the trades and I'm even proficient at some. I am familiar with and at least conversant in almost all of the Technologies and Sciences, both 'Hard' and 'Soft'. My approach tends to be that of a 'Problem Solver' and with my varied background and wide ranging interests and knowledge, I am able to access and utilize information and knowledge from many varied fields

As with many things, I follow the search for the 'GUT' with ongoing interest.

(8 >) Live Long and Prosper (< 8),

DougRH

Hi all,

I have been following this discussion and have some questions.

The linear vs. rotary input, is this referring to the power produced by the engine, input to the transmission?

Or is this referring to the what I would call the" gear shifting mechanism" ?

If you could put this in layman's terms, it would be most appreciated, I don't have any engineering or machinist's training, but a lot of experience breaking mechanical things and then trying to repair them.

If you get a prototype running , I would be suitable as a worst case operator to find any weak points, I could break an iron wedge.

Good luck with your endeavours,

Packrat

Hi PackRat,

I am refereeing the shifter mechanism that only travels back and forth in a straight line on a flat plane

The 'Rotary' reference refers to using a rotary motor with what is basically a flat belt and pulley on the motor and a spring loaded idler pulley at the other end of the shifter mechanism travel.

I already have all of the tools and qualifications that you refer to in my 'arsenal' already myself thanks. LoL (< 8)

Keep on Keeping On!

So are you going to be able to compete with the existing on the shelf market of compact electric over hydraulic (drive by wire) variable displacement pump and motor systems that are now pushing the 150 continuous and 300 peak hp capacities with gearing ranges from near infinity:1 to 1:2 overdrive and at 97+% average efficiency with 10K+ hour service life expectancies for under $2500?

If your curious about the basic lower end electric over hydraulic pump units in this power capacity and smaller they are common surplus now for around $1000 from WWW.surpluscenter.com. And thats new old stock! Put a $500 hydraulic motor behind it and your good to go!

The big boy stuff on the market now is pushing the 1000 HP peak capacity for around $20K or less. If your thinking big trucks and buss applications $20K is only around 10% of the sticker price for a good quality over the road rig new. Just getting .5 MPG more on average over a 2 million mile minimum life expectancy more than justifies it.

All the big name hydraulics manufactures are making the drive by wire hydraulic pump systems and have been making them for commercial industrial applications for some time now so its well proven technology.

To save money and lower the life expectancy is not hard to do either. Just under size the system over drive it.

But don't mention the aliens, the apocalypse, and don't wear the foil hat when you talk to potential investors!

Hi tcmtech et al,

Firstly my primary market is mass manufactured and sold personal automobiles. My CVT does have the capacity to be scaled up and made rugged enough for large commercial and industrial applications quite readily.

In regards to 'second hand equipment' prices, I don't know of any automobile manufacturer, or large industrial equipment manufacturers either that puts such 'used / second hand' equipment in new vehicles. Do you? Regardless once they are getting mass marketed, new units of my CVT will quite likely be lower priced than the prices for comparable used hydraulic systems that you quoted. I am not aiming to provide a few dozen or hundreds for specialized racing applications and for back yard tinkerers, though my CVT could be utilized by them with the same advantages that it supplies to main stream autos. Once it is has been used in the mass market for years, and there are used 'surplus', models around, they will undoubtedly be significantly lower cost than either of the units and there prices that you mention.

I am aiming for, and feel that I have a product that IS valid in markets where it literally will be used hopefully by the millions cumulatively over an extended periods of time. Regardless, my CVT is considerably simper with a much lower part count and does not the kind of manufacturing precision that is needed for Hydraulics: especially in the control valves. As someone who has spent years repairing, rebuilding, modifying, upgrading and building custom hydraulic systems, I am fairly well versed in them. Though I make no claims to 'knowing everything about hydraulics'. We all know that the 'power density': the 'power to weight &/or volume' ratio of hydraulics is phenomenal. The accuracies and control of hydraulics especially in 'drive by wire' remote control becomes more critical the faster a vehicle goes. Most heavy Duty Industrial equipment does not travel at anywhere near the speeds that personal road vehicles do. Also the flexibility of hydraulics that allows them to be used in ANY location and position is hard to duplicate, especially with the kind power density that hydraulics are capable in any position with the power being supplied via flexible hoses and tubings for many applications is unbeatable. However My CVT is designed to be part of the power train, though of course it could be utilized in anything that needs speed &/or torque variations. There may be industrial applications where my CVT has the best overall advantages, and others that it won't. One thing for sure, my CVT manufacturing cost is lower than everything that has been spoken of here, including the 'ToroTrak'. I estimate that my CVTs manufacturing cost will concretively be less than 20 % and more likely closer to 10% in high volumes of a 'ToroTrak and is a MUCH simpler, more compact transmission and very likely will give a MTBF many times that of a ToroTrak. I could adapt a sun and planet gear system and utilize it in the same fashion that they do, but frankly the considerably added complexity and expense isn't warranted, though it could be utilized by any licensee that wanted to do so. Also the ToroTrak utilizes a Drive Chain as a crucial part of the power train and the limitations and down side of such arrangements for mass market vehicles with long life cycles is very well known and documented: thus it is never used unless there is absolutely no other way to do it. They are even phasing drive chains out in motorcycles for very good reasons. Excepting perhaps the dual complimentary variable radius spoken of here as is used in snowmobiles and has been scaled up with some success, but is limited to fairly light vehicles because of its power limitations. Except for the 'SnowMobile' IVT, my CVT will be a lower cost to manufacture than any other transmissions mentored here or that is already on the market that I am aware of. There have been many attempts to adapt the SnowMobile IFT to light automobiles with disappointing results. My CVT does NOT utilize any friction elements to transmit power and torque, it is all directly mechanical. This IS a significant advantage over most of the IVT/CVT that all rely on friction to transmit the power; which means that even very minor wear will render a very significant loss of efficiency and MTBF which will result in them needing and requiring a very expensive rebuild quite often.

The design of this CVT is such that many of the internal parts, and in some cases, all of the exact same components can be used in different makes and models

When pitching this to potential clients, like everyone else these days I will be emphasizing the 'Green' aspects of the CVT which ARE legitimate. But I'll leave it to someone else to 'beam them up.' (< 8)

Regards,

DougRH

I'm wondering if you can redefine the problem?

How many discrete positions does your slider need?

is there a way to divide up the work into many 2 position actuators?

Is the speed of the stroke requirement absolute for all parts of the travel?

of course if you increased the stroke, you would increase the amount of acceptable error. The downside would be the speed of the stroke would also have to increase.

Probably all dumb questions, but it never hurts to ask....

Hi Garthh,

The number depends on the design of the CVT; The initial one will probably have ~ ten ratios/positions per stage/range, with 2 stages/ranges so there will need to be 2 such linear Actuators. For each discrete gear ratio, there is also a 'neutral' position for each each ratio + 1 more neutral position per stage/range. Each distinct gear ratio will likely be ~ 1" between each gear ratio.

I don't see the cost/benefit ratio, which is crucial, being better with numerous position sensors and all of the extra complexity needless being added. Also, if at all possible, I want the sensors to be mounted on and be part of and move with the shifter mechanism and actually sense the exact position where the shifter needs to be when it engages in that gear ratio so that other unnecessary errors are avoid as might occur if the 'position sensor' ends up being mounted on a rotary motor, etc.

The speed for a 'gear shift' is not a 'fixed' spec, but by virtue of the fact that there will likely be ~ 10 times more closely spaced gear ratios than other transmissions, it will be almost constantly shifting gears and needs an 'automated' clutch to change gears. FYI: At this point in time I am thinking of the 'clutch' mechanism being a standard clutch or of the 'band (brake) configuration' and NOT a torque converter. Other than perhaps a small lubrication pump, I don't foresee this CVT being a 'Hydraulic' unit in any way, shape or form. Though with the forces involved, the 'clutch mechanism' may be hydraulically actuated. So the faster that it is able to accomplish each gear change 'cycle' the better. I want these events to be a as quick, effective, quiet and smooth as possible.

In my book, the only dumb questions are the ones that don't get asked for fear of appearing to be dumb when one wants/needs to know some info that they don't know and don't ask.

I appreciate all of the questions, observations, inputs, feedback and objections here. They ALL help me to define, prioritize, refine and assist in working towards the best possible solution.

So thanks for the (not so dumb) questions.

Regards, (< 8)

DougRH

I looked again at your concept. I do not want to say it is good or not since I do not know it but with respect to the positioning of the slider I would suggest to use the same principle as for the elevator cabins. If you have a simple presence sensor in every position the slider has to take and you know where the slider is via the signal the sensor feeds back then you can give an order to go further or back according to the decision of the controller.

This principle has at least the advantage that the slider will stop at the right sensor and the changes in the distance between sensors will not influence the precision of its end position.

I do not want to go into more details but I think that for your concept which does not require a "continuous" slider position this "indexed" positioning will be the simplest and most robust solution. The microprocessor you will be obliged to use could take care of all aspects as it does to day in a lift.

Hi Guru,

There is a LOT of merit in this proposal. Do you know of any such integrated linear positioning mechanism that would make this possible in a compact package and at a reasonable cost?

Just a reminder that the amount of power required is very low.

Thanks Again, (< 8)

DougRH

It is not integrrated but can be build easily with available components normally used for automation and thus low cost and proposed in almost all suppliers catalogues. I think about inductive sensors ON/OFF. Some are quite small 3mm in diameter.

Hi Nick,

I am unfamiliar with this type of position sensing system. Would the 3mm diameter sensors be able to reliably meet the precision of ± 0.005" ?

I have thought about just machining a groove into the positions that it needs to operate in, including the neutral ones, and then putting a mechanical push button switch that is 'NO' until it hits the machined groove to tell the logic that it is at a designated position, but there are too many limitations, problems and shortcomings with such a set up.

Regards,

DougRH

Yes

Hi NN et al,

Your realization of the fact that this application is a series of (identically) indexed locations and thus the utilization of a 'Location/Position' markers and sensing each such position is an excellent one if it can be implemented cost effectively.

From your specific information (the 3mm diameter) I think that you have a specific type of sensor in mind. Given the environment with the inevitable presence of quite fine metallic particles that will foil and render any 'magnetic' solution ineffective and likewise the presence of the quite dark petroleum lubricant that will inevitably end up being quite hot from friction must be taken into account and thus would seem to rule out an 'optical' solution as well.

What type of 'positional markers' and sensing mechanism do you think will fulfill these requirements including a reliable accurate positioning of ±0.005" effectively over the life of this CVT?

Regards,

DougRH

The oil & metal dust won't be a problem, the shape of the sensing zone will determine the accuracy

You might poke around here on the digikey site

Hi GarthH.

I'll check the site out that you posted for me thanks. I get the sense that you have a specific type of linear sensing, positioning with feedback and error correction as well as perhaps the actual linear 'rail system' in mind that will be long lasting in this challenging environment? I'd appreciate any ideas, thoughts, insights and suggestions that you many have.

As 'NickName' correctly pointed out, the positioning of this mechanism is a series of (quite likely all equally spaced) discrete positions as opposed to being an 'infinite' number of variable positions that may allow me to come up with a much more cost effective solution. From what I have seen so far, I don't see buying a linear actuator as being cost effective. It will most likely end up being something that is fabricated &/or machined and going back to my original idea of an external rotary stepper motor. If I can get the indexed positioning sensors of the actual shifter mechanism, the accuracy will be much better and more reliable than if it is sensed on the rotary stepper motor which brings in more significant chances of errors, especially as the CVT ages and wears. Especially in the (demonstration) prototypes which will require being accurate and rugged, but won't need the kind of life span and durability that mass produced production models will need to and will have.

One thing that is going to be a (very) challenging issue is gong to having an 'automated' 'manual'' clutch that is capable of proper, smooth engagement for standing starts and to a lesser degree coming to a stop. Fortunately more and more automobiles and light trucks now have active 'traction control' which can be utilized to greatly assist and accomplish this task.

Thanks again,

DougRH

Hi Doug,

Read your thought on the clutch being a challenge.

I remember reading about a small car that Lancaster was developing in the '50's.

It had an automatic transmission, that if I remember correctly, had been developed in house at Lancaster. Apparently it performed very well, except for , at the time an, insurmountable and unacceptable clutch pack friction surface wear problem.

This occurred in what they described as over run conditions, not sure what that is exactly in Britspeak, but am assuming it was closed throttle coasting or engine braking condition. They couldn't solve the wear issue and canceled the whole project.

The reason I'm mentioning it , the drive train performed, by all accounts wonderfully, otherwise.Maybe if they had digital control system technology they could have solved the problem. The tranny was hydraulic but maybe the design had elements that could be adaptable to an electro-mechanical system. Might be worthwhile to look at , even if for the" how not to do it insight".

I'm just saying.

Best wishes on your endeavours,

Packrat

Hi PackRat,

Thanks for the info, I'll see if I can track anything down on it. When you are referring to 'Lancaster' what immediately comes to mind for me is the WW2 'Lancaster Bomber' but I doubt of these are related. Anything further that you can remember to help me identify it would be great.

In regards to the clutch I have a simple elegant design in mind that in effect is an 'automatic' mechanical manual clutch that doesn't require any hydraulic cylinder, lever, actuator etc to operate it. I'm not going to say too much about it on here for the moment until I check out the patent status of it.

Thanks,

Doug[i,

Hi Doug,

I realize you are approaching the shifting accuation in a non- hydraulic way, but I thought the clutch pack system might be interesting to look at. Lancaster was one of those companies that was around at the beginning of the auto industry in Britain. Seemed to have an engineering mindset when it was founded. I think they later were absorbed into one of the larger car companies.

Packrat

Hi PackRat,

K thinks I will check into it. Then you are referring to it a as a 'pancake' style, it sounds to me like the familiar disk clutch, only they had a couple of friction elements packed in between the flywheel alternating with a number of solid disks. Thus enabling them to get a higher capacity clutch that would of otherwise have to have been considerably larger. Is it like a 'stack of 2 or 3 clutches stacked up in a much smaller OD Do you know what I mean? I'm not explaining it very well (I'm half asleep)

If you understand what I mean can you please tell me if I am talking about the same thing that you are or not?

Thanks,

DougRH

Hi Doug, It's been a few years since I read about it, have since lost the book that had the description of it, my foggy memory , seemed like there was something interesting about it, but now can't picture the details. Might have been a clutch stack, can't remember if it was dry or in a viscous fluid . After posting, tried to find information about Lancaster cars, no luck so far. If I find any relevant info I'll post , otherwise it might be more of a distraction, not time beneficial to you.

I'll see what I can find.

Packrat

Hi PackRat,

Thanks for the info, time and energy. I appreciate it.

I don't have anything in mind

Just trying to get some brain storming going, kind of like what would happen if we were sitting around swapping lies & tall tales between bouts of serious discussion

The clutch you are describing would be commonly used on a motorcycle.

Maybe a rack & pinion set up? a series of sensors would sense relative & exact position somewhat like a vernier scale [slide rule]. The teeth wouldn't have to be exactly the distance between stops. You would end up with a truth table, that isn't exactly straight counting.

I don't know if it's possible, just riffing...

Hi GarthH,

I understand and appreciate your ideas and input. Such sessions are held and used just because of the solutions that can be relatively quickly identified that might otherwise never even have been put forth and perhaps point out the direction to follow to find and implement the best solution.

I think that a rack and pinion would be too expensive and the trouble with any gears, lead screws etc, there is always also the necessary clearance required that makes them inaccurate and worsens over time with wear. Also there is nowhere near enough force required to shift the CVT that would necessitate the expense required to implement and utilize a rack and pinion set. Thus I don't see it being a cost effective solution.

One of the excellent features of my CVT is that it is a very cost effective solution and does not require or use anything as complex as gears. Though this is a mature technology, my CVT does not require any such complex items that have to be made to very exacting specifications including the machining and heat treatment and grinding of gear sets

One idea that I am trying to track down and learn about is the use of precision linear positioning devices such as are used in CNC machining and the accurate digital readout linear positioners that are coming into use more and more as retrofits on older manual machine tools as well. They work exceptionally well and are used over extended periods of time trouble free and very reliably in a harsh environment as far as their chances of sustaining physical damage from the often VERY hot and VERY sharp metal cuttings as well as liquids coolants in abundance. This does not include almost constant exposure to hot petroleum based lubricant though. But I have a strong feeling that these can (be made to) withstand these as well.

The problem is really twofold: the positioner itself and the positioning sensors. Because of the fact that all the intervals are the same, I have considered using something like a series of hardened grooves in the stationary locations and just using something like a spring loaded ball bearing that will push down into the groove and locate it properly when it gets close. There are a couple of problems with this. They first one is wear, primarily of the grooves, and the weakening of the springs and the cylindrical followers/positioners' that they operate within. The spring loaded followers could be easily replaced and an OilLite bushing that are fairly inexpensive and easily replaced can be used for these 'follower mechanisms'. A 'locator strip' with the locating grooves can be made so that it is readily (surface) hardened. The accurate locating of such bars is a mature and well developed technology with numerous options. In this scenario it might even be possible to do way with the sensory feedback and correction technology. It just has to be substantial enough to seat firmly in place. Multiple locators could be used. There could even be mirrored such mechanisms on both the moving and stationary parts. There is no force vector involved that will try to move the shifter slider sideways in operations. Also as you may have encountered, I am going to add a slight 'self centering' aspect to where the shifter mechanism locates on the 'shifted' components, including the neutral position between each 'gear ratio and beyond both ends of shifting range. The down side of using a strictly mechanical solution is that in order to make it 'solid, accurate and reliably repeatable' the spring force required to locate and accurately position these in the grooves, is that the force that it would then take to disengage these self pensioners and move them will require more force, which is otherwise very low. In such a scenario, some looseness and 'sloppiness' of the locating mechanism is tolerable and even desirable. The locating mechanism will get it close and the self locating mechanisms will ensure the final correct position. It is starting to look like an external stepper motor with a steel band or cable on the pulley on the motor and a spring loaded tensioning idler pulley on the other end may be the best solution after all. Though this will most likely, but not necessarily require an active sensing and feedback positioning system.

In the auto manufacturing as in many manufacturing businesses they try to keep the manufacturing costs as low as possible but actually work at making the repair costs higher. With the advent of the Asian manufactured products obtaining an ever increasing market share of north American automotive sales that north Americans are able to compete with; the north American manufacturers are becoming more and more dependent on repairs for their profits, especially in the low end of the market; which are essentially lost leaders for repair parts. Especially for north American manufactured products. A sad state of affairs and one which is rapidly disappearing both because of competition and because of the rapidly ever increasing necessity of maximizing the usage of all resources with the smallest possible impact on the environment. All of these same factors are starting to make an impact on European manufacturers as well

One issue that I haven't addressed on here so far is 'reverse.' These will be the only (idler) gears in the CVT and with a normal shifter mechanism it is not hard to accommodate and adds very little in the way of complexity or expense. For these I will identify, design and utilize ready made parts for all prototypes and evaluation units. It may be possible to utilize a CVT shifter positioner for this as well, though a separate (solenoid) activated device or some such similar device maybe necessary. I haven't given much thoughts to the details of implementing this as of yet.

Many such details as the clutch, shifter positioner, reverse gear etc are not necessary for the patent of this CVT itself which has the unique ability of transmitting power and torque without relying on any friction elements to do so. However in selling and marketing it effectively and for the maximum return it will make a very significant difference if a fully functional CVT can be presented and demonstrated and licensed for evaluation and production.

Thanks again GarthH,

Later thinking about it some more & reading your reply...

Forget the pinion, just use the rack as,a shift gate. A combination of a few prox's to find the rough location & a locking pawl for final. Since the pawl wouldn't bottom out accounting for wear would be covered.

The shifting motion actually accomplished by the externally driven chain or cable drive. This kind of drive is well suited for an incremental encoder mounted [or built]on the motor. A sub routine in the software would be able to discover & account for the inevitable missing bits [pulses].

The entire travel could be divided into several regions. The locking assembly above would provide a failsafe for power outages, staying in the last position until the plc boots back up.

As you have pointed out the end users are more than capable of handling all this, you just need a rudimentry solution to allow for demonstrating the actual innovation...

Hi GarthH et al,

I agree, I'll likely use small milled slots for the required 'in gear' locations and the multiple 'neutral positions' with making the 'in gear' slots deeper and hence more 'positive' than the 'neutral' positions where they have substantially less force on them.

I'll likly use some silicon bronze rods with a hemispherical end on them instead of ball bearings. If I get one that I need to have a longer MTBF I'll likely use a 'work hardening' material rather than heat treatment which always warps things and then requires extensive and expensive grinding to refinish it. Mind you if I utilize a simple case hardening process with a large tip on my OxyAcetelyn torch that will heat treat just the grooves very quickly and just do them one at a time manually, though it is likely it will bow it somewhat, it will still retain enough flexibility in the majority of the material that I can pull it flat when it is bolted to the housing. I can reduce the cumulative bowing by not case hardening all of the groves sequentially, but by spacing them out, much like a head torquing pattern used to reduce warpage and ensure the best all over seal. I can even do some subsequent stress relieving heat treatment in my convection oven and freezer. If my 'gear shift' locating strip requires significant milling, especially if it tends to all be on one side, I'd rough it down first and stress relieve it before the final finishing anyway. There tends to be much less problems with work pieces turned on a lathe because the material is all taken off symmetrically versus milling. Though heavy roughing and or starting with a casting or a forging which tends not to be anywhere near as close to being evenly symmetrically as round stock does can and does induce warpage both from stresses being induced in roughing and because of releasing stresses induced during casting cooling of castings and both induced from forming and cooling during forgings. In the 'old days' hotroding and autoracing engine builders utilized OLD blocks and heads as a starting point because more inherent stresses have been considerably relieved by the multiple heatings and cooling from extensive normal operation and usage. FYI: Likewise many precision 'flat/trued' objects utilized in the machining industry, primarily gauge blocks &/or large milling blocks/tables are made from rough workpieces that have been left sitting outside for sometimes up to 25 years because the seasonal temperature changes relieve the stresses in them. Obviously the larger the variations in temperatures the better and more effective this is. Mind you, all of this is typical of my tendency to over engineer everything. Unless I get one that is going into an extended service test, then I can use a slightly higher grade of cold rolled mild steel will do it or I might use 4140 or 4340.

For the major shifted ratio altering components for the first prototype they will be identical and just made out of aluminum. (I've even considered a hardwood) and there won't be an actual change in ratio but are just all 1:1 to test and refine the shifting mechanism itself. Then perhaps implement and refine my 'reverse gear' shifting mechanism with this same 1:1 setup as well.

I have come to the conclusion that the 'passive 'automated' manual clutch mechanism I have in mind will likely be able to work in conjunction with the ECU for shifting once underway, but will not be sufficient or effective for standing starts and stops. Hence I continue to mull this over. There is the possibility of a computer operated manual clutch working in conjunction with the ECU, but this requires significant force to operate. Especially as operational models will be primarily for demonstration purposes only I'm considering the usage of a ferro-electromagnetic clutch to handle the starts and stops. However potential licensees will look at this as part of the 'whole package/solution' and likely consider it to expensive. Another automatic possibility is the automatic clutch that some manufacturers use to impairment passive 'on demand' 4 wheel drive. It is basically a rudimentary and much more compact (thinner) torque converter. The working fluid is a fairly thick silicon liquid that heats up VERY quickly and thickens considerably as soon as there is any difference between the 2 wheels that are constantly driven and the 2 normally unpowered wheels speeds. I wonder about the effect of significant changes in ambient temperatures in such a setup. Again, this would be a relatively simple but expensive solution. Perhaps the best solution is the most obvious one that is already in very wide usage: a torque converter, perhaps in conjunction with the 'automated manual' clutch that I am considering for decoupling the power during shifts once underway. These would help to facilitate the limitation of the design of this CVT that has no 'syncro rings' and help achieve this function.

As I have stated before I am also considering utilizing a 'band clutch' such as is used in current automatic transmissions, and more commonly as band brakes in industry. Though I have adjusted the bands on numerous automatic transmissions that require occasional manual adjustments of them, I am not very familiar or knowledgeable about automatic transmissions and don't know or fully understand just how these 'bands' are utilized what their specific function actually is. I'd appreciate being enlightened about these specifics by anyone that knows and understands this.

I'm wondering about another aspect of current automatic transmissions: does anyone know if and how the transmission is uncoupled (the equivalent of stepping on the clutch petal in a standard) from the engine briefly in current automatic transmissions when they shift gears? What do they utilize to do this and how do they do it or do they truly shift 'under power'? If so, how do they accommodate shifting under load/power without grinding and destroying the gears in them?

Thanks once again to everyone for all of your help, knowledge, thoughts, ideas, inspirations and input! (< 8)

Doug

I think the planetary gear sets allow both ratios to be engaged at the same time during shifting.

And how 'bout maraging steel for the detent rods?

Pack

Hi There PR,

What is 'maraging steel' please?

Thanks,

Doug

Hi Doug,

Maraging steel

Hi PR561,

I'm familiar with the materials and there properties and uses, but didn't remember the term. One such consideration in such designs where there are two parts in contact is which is the cheapest, quickest and easiest to replace. Thus in an instance like this, the 'rack' or grooved locating strip would be given a significantly harder and more wear resistant surface than the spring loaded locating plungers. Thus my references to a temperature or work hardening steel for the rack and a softer material with good bearing qualities to it for the plungers. I don't know if you are aware of the difference that the high silicon content in materials that are both both light but strong. Some heavy duty diesel pistons have up to 25% silicon in them which has a VERY significant difference both in there wear resistance and the ability to withstand significantly higher temperatures than such light metal alloys otherwise could.

Like yourself I'm no Engineer, though I do have some minimal training in it, but thats a 'whole other story.' I suspect that much like yourself most of my knowledge comes from the 'School of Life' and I'm mostly self taught in a very wide variety things comes from my inherently curious nature with a fierce determination to figure things out and understand them. Like many others such as ourselves, I use 'thought experiments' quite effectively. When I need more information, knowledge and understanding I go looking for it and delve into it. My approach to things, especially of the 'physical realm' is one of an 'applied problem solver'.

I have had 'differences of opinions' with people that have PhD s and Doctorates in Physics including somethings that are quire fundamental and my 'score card' is higher than theres. (< 8)

Regards,

Doug

Hi Doug,

You wrote:

As I have stated before I am also considering utilizing a 'band clutch' such as is used in current automatic transmissions, and more commonly as band brakes in industry.

These are used as brakes (not clutches) in automatic transmissions, too. The gear sets in a standard automatic trans (the type with bands) are planetary and use clutches and brakes to select which elements rotate and which are held stationary, thus changing ratios. The clutches are multidisc stacks, about 5" in diameter, typically. (The How Stuff Works presentation is very good, but to really see how this stuff works, it is good to disassemble an old automatic and take a look.)

I'm wondering about another aspect of current automatic transmissions: does anyone know if and how the transmission is uncoupled (the equivalent of stepping on the clutch petal in a standard) from the engine briefly in current automatic transmissions when they shift gears?

Jumping back a couple decades: one of the neat things about automatic transmissions is that they would shift under full throttle, because there was never a break in power flow. Overrunning clutches are used so that a gear can be engaged at the same time as the next higher gear, and whichever is tending to turn the output shaft faster takes all the load -- with no lag, and perfectly smoothly.

Now in "standard" automatics, shift control is electronic over hydraulic, and it is possible to do subtle things with throttle by wire, etc to control feel at shifts, but the basic principle is still in force: that two gear ratios can be engaged simultaneously, with sprag clutches (overrunning clutches) being use to keep shafts from snapping and gear teeth from flying off. This same principal is used in the double clutch transmissions to preselect the next gear while the previous one remains engaged.

Incidentally, double clutch transmissions use the same kind of wet multiplate clutch used in automatics.

Also incidentally, I notice that the new (2011) Ford focus will be offered with a double clutch transmission as an option -- so these have already made their way down into about the cheapest layer of cars. Throttle-by-wire enables these transmissions to execute perfect downshifts, throttle blip to match speeds, and all. The standard manual trans in the Focus will be a 6 speed, and I'd guess the the double clutcher will be 8 speed, (although it could be 6 or 7, too.)

Hi Blinky et al,

Everything was pretty well as I figured it was. When driving and automatic it very much feels like it is shifting under power.

Being an 'open wheel' racing fan: F1 Champ Cars, CART or whatever it is that the ones that are left now are called, I'm familiar with the dual clutches setups that F1 cars have had for some time now, the speed that they change gears at is quite phenomenal.

Though I watch open wheel racing, I would never race in such a series (I'm way to old now anyway), racing in such close proximity with those open tires making contact is just plain crazy!

I've thought about it and if I was doing it I would have thin carbon fiber 'bumper strips' on the outside of the tires that prevented such contact that would be hinged at the front and flipped up out of the way for tire changes. OK, so I would be in sports cars with fenders to rub up against before the tires would. LoL (< 8)

While on the topic of carbon fiber construction, anywhere where they have to literally bolt something to the carbon fiber structure, I figure that they must have a large nut, threaded metal plate etc embedded into the carbon fiber both to take the VERY high concentrated loading in general and the threads themselves in particular. I hope I get to the point of this being successful and then get my engine into usage so that I can have a go at building personal flying (urban) transportation vehicles and I'll get to get all gooey playing in the carbon fiber. Oh Joy: NOT! I'll be wearing a sealed air supply if I'm in those types of fumes and 'mummified' before I do.

Thanks again Blinky, your such a cute lil furry creature, (< 8)

Doug

My rack suggestion is intended to let you use an off the shelf item [obtainium]

there is always the basic equation, which must be satisfied

Do you have more of

Time Or Money?

I'm glad we got this discussion rolling again & hope we can help you come up with a reasonable solution.

Hi GarthH,

I don't currently have much of a surplus of either, but money is most definitely what is holding me back the most. But I'm splitting up my time and working on the money part of the equation while I do this R&D and use my time by refining the design to the point where I can get the patent happening and the CVT can be prototyped and refined.

I can't imagine any rack being small enough for my needs unless it came from a high quality large scale model. (< 8) Also, unless I used a VERY large 'bearing, hemisphere etc to sit up very high in the wide gap of the rack teeth, the sides would be way to steep of an angle. I think we are working on significantly different scales. I'm thinking of the spring loaded plungers being about 1/4" in diameter and the locating grooves being about only an 1/8" of an inch deep. That's all I'll need. I could probably get away with just one of these but I'm thinking I'll use 2 x 2 of them in a square or rectangular layout which I seems to be a good balance. As I said, I want to keep the power requirements down as other than this type of mechanical locating arrangement the heaviest load will be when it is really cold out and the heavy gear oil thickening up. I have encountered Japanese mass market manual transmissions that use a very much lighter oil in them and I'm aiming to keep the lubricant as light as possible. I'm still working with the idea of a stepper motor with thin, light spring steel band or light cable and two pulleys as the moving mechanism. So far it seems to be the most cost effective, especially if using this low tech mechanical final locating arrangement. I don't see the power requirements for the shifter even being as much as a windshield wiper motor. I don't want to get it where I'll have to use a starter motor to move the shifter mechanisms. LoL FYI The prototype will likely have '2 ranges' requiring 2 shifter mechanisms which will give it a VERY wide range of 'gear ratios' Compared to todays current 'old style' automatic transmissions that have been in use for decades, I guestimate that the cost of manufacturing my CVT will be between 20% ~ 25% of what they cost to manufacture. My engine will be in the same ball park for relative manufacturing costs.

As you are likely aware of, the first mass produced Fords had huge bores with a very long stroke but with a VERY low compression ratio. So why didn't they use electric starters earlier than they did? Of course electric motor technology was nowhere near what it is today. But when Engineers calculated the amount of power that would be needed with the arrangement they had in mind, the electric motor was about the same size as the IC engine block! The big 'break through' came about when someone finally took the duty cycle into account and that especially with the very significant mechanical advantage of the very small starter gear turning the huge ring gear on the flywheel, that they could use a much smaller motor and allow it to get hot for the very short time it was needed. Even today, the recommended duty cycle for most starters is 15 seconds every 10 minutes!

I also have some other things in mind that will significantly improve the efficiency, techniques and processes of power systems in general, but I want to be around to accomplish these things so I'll say no more about them at this point in time on this public venue.

Regards,

Doug