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Participant

Join Date: Aug 2018
Posts: 3

Square Ball Transforms U-Joint

08/07/2018 9:33 AM

Wanted to share this patent-pending design for intermittent applications.

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Guru

Join Date: Mar 2007
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#1

Re: Square Ball Transforms U-Joint

08/07/2018 9:45 AM

I don't see any advantage here over other designs....

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#2
In reply to #1

Re: Square Ball Transforms U-Joint

08/07/2018 10:50 AM

WOW, you sure know how to rain on a guy's parade.

Maybe small, intermittent use, as OP said.

I don't see any positive capture of the parts, except the two mating shafts????

I don't see it carrying much of a load, either.

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Guru

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#3
In reply to #1

Re: Square Ball Transforms U-Joint

08/07/2018 10:54 AM

I would agree. A conventional u-joint has bearings with rollers inside (rolling friction only). This new design has sliding friction between the pins and the square bearing, as far as I can see. If there is a loss of lubrication, I would think the newer design would be more prone to failure with the seal keeping the lubricant inside constantly flexing.

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Participant

Join Date: Aug 2018
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#21
In reply to #3

Re: Square Ball Transforms U-Joint

08/09/2018 10:55 AM

You are correct that there is sliding friction, but it isn't occurring between the pins and the Square Ball. The sliding friction happens between the ID of the yoke and the OD of the Square Ball. Torque is transferred through the square features of the Square Ball causing it to seek its own center within each yoke. The pins are not in contact with the Square Ball when it rotates through an angle, they are only needed to keep it from sliding out of either side of the yoke when it is stationary. We were able to prove this in a test by removing the pins and spinning the Square Ball Universal Joint at an angle. As soon as the assembly stopped spinning the Square Ball would slide out of the yoke cylinder. So the retaining pins are only needed to keep the assembly intack when it's in the relaxed state, they don't transfer any torque.

The seal design has proven to be quite effective. It has passed a submersion test at 3 meters deep for an extended period of time and not allowed any water into the sealed area, additionally there wasn't any grease purge. The constant flexing is a benefit, it continually pushes the lubrication around the sliding elements ensuring they stay lubricated.

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Associate

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#7
In reply to #1

Re: Square Ball Transforms U-Joint

08/08/2018 7:14 AM

Less parts would be an advantage? - 8 including protective bellows.

"An engineering designer has many definitions but one is 'an engineer who can think simple'. The solutions to problems at all levels proposed by good engineering designers will always appear too simple and obvious to have any value. But therein, of course, lies their value to the community...!" Mike Osborne (IED Secretary 1988-2000)

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#12
In reply to #7

Re: Square Ball Transforms U-Joint

08/08/2018 11:13 AM

Not if it wears out twice as fast...and costs twice as much

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Participant

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#17
In reply to #1

Re: Square Ball Transforms U-Joint

08/08/2018 6:29 PM

I can help with that. The Square Ball Universal Joint was designed to solve problems our customer was having with a conventional needle bearing u-joint in their steering linkage. The conventional u-joint has about 70-120 individual components per assembly, so the design is susceptible to tolerance stackup issues. This results in a wide range of starting and dynamic torque values from unit to unit. Additionally, the environment of their vehicle was challenging to the four wiping seals on each u-joint.

The Square Ball Universal Joint only has three components susceptible to tolerance stack up issues, two yokes and one Square Ball. The result is consistent starting and dynamic torque values that are also very low. Additionally the boat seal doesn’t wear away like a wiping seal eventually does in challenging environments.

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#18
In reply to #17

Re: Square Ball Transforms U-Joint

08/08/2018 8:41 PM

BMW

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#19
In reply to #18

Re: Square Ball Transforms U-Joint

08/08/2018 10:06 PM

Looks too complex to me.

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Guru

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#4

Re: Square Ball Transforms U-Joint

08/07/2018 1:28 PM

SIX u-joint versus HALF-DOZEN u-joint...only prettier?

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#9
In reply to #4

Re: Square Ball Transforms U-Joint

08/08/2018 9:35 AM

Needle bearings in bearing caps add maybe 50 separately manufactured parts to a U-joint assembly....

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Power-User

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#5

Re: Square Ball Transforms U-Joint

08/07/2018 11:29 PM

Does this design maybe get rid of conventional U joint / cardan shaft angular velocity variation? (new type of CV joint?). I can't look at this long enough this late at night to analyze the rotary motion, but it looks like it might be constant velocity?

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Guru

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#6
In reply to #5

Re: Square Ball Transforms U-Joint

08/08/2018 4:42 AM

One of the problems with CAD animation is that to get it to work and look amazing you sometimes need to impose hidden constraints that have to exist in real life. For this to work the balls must be restrained in a cage or when the input and output axes are aligned the balls are free to settle anywhere along the curved slots. If the axes were vertical the balls would drop to the bottom at which point the joint can no longer bend. (assuming that you have added stops to prevent them from falling out of the grooves). In fact if just one ball is misaligned the joint will not bend. But once the balls are fitted into a cage the joint cannot be assembled unless the outer cup is cut into segments and then locked into place around the inner sphere and bearing cage with an additional external retaining ring. At that point the simple elegant design shown becomes very complex and ceases to have the displayed merit.

Note to all aspiring CAD designers. To have any value, once you have drawn it, somebody has to be able to make it. Understanding how it will be made is an integral part of the design process.

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Power-User

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#8
In reply to #6

Re: Square Ball Transforms U-Joint

08/08/2018 9:29 AM

The point was constant velocity or not, not a primer onCAD design...

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#20
In reply to #6

Re: Square Ball Transforms U-Joint

08/09/2018 10:42 AM

3D printing might get over the challenge of the assembling bit.

Else I agree with your statements.

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#10
In reply to #5

Re: Square Ball Transforms U-Joint

08/08/2018 10:14 AM

It takes two joints to get constant-velocity, just like regular u-joints.

"Constant velocity can be achieved when assembled with two properly phased and equal-angled joints, the same as a double Cardan CV."

https://industrytoday.com/resources/square-ball-redesigns-century-old-u-joint/

Double Cardan C-V joint.

https://d2t1xqejof9utc.cloudfront.net/screenshots/pics/bf2afd898c99cf7f4c1e85cc71035018/square.gif

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Power-User

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#22
In reply to #10

Re: Square Ball Transforms U-Joint

08/09/2018 11:00 AM

There also is a constant velocity joint that you typically find between your transmission output and your front driving wheels, in modern automobiles. Achieves constant velocity without double Cardan or U-joint assemblies.

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Guru

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#11

Re: Square Ball Transforms U-Joint

08/08/2018 11:01 AM

How can I get a sample of this X-joint?

Who in the company do I contact?

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Guru

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#13
In reply to #11

Re: Square Ball Transforms U-Joint

08/08/2018 11:23 AM

I was wondering if one physically exists as well.

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Guru

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#14
In reply to #11

Re: Square Ball Transforms U-Joint

08/08/2018 12:32 PM

Might just be a prototype...

https://www.cctybearing.com/sales-team/

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#15
In reply to #14

Re: Square Ball Transforms U-Joint

08/08/2018 2:58 PM

I sent a sample request to China already.

They claim they will respond within two days.

We'll see.

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Guru

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#16
In reply to #15

Re: Square Ball Transforms U-Joint

08/08/2018 4:08 PM

The inventor of the U joint just called me from Ill.

John and I had an interesting talk.

It is in the prototype stage with one commercial application as a steering rod U joint.

Their customer requested a solution to this specific application and they are looking for other markets to develop.

He is sending a "key chain" sample that represents the finished joint.

More later.

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Guru

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#23

Re: Square Ball Transforms U-Joint

08/16/2018 8:09 PM

The prototype sample came. No rubber boot, but that's fine. Just like opening a Christmas present.

No surprises inside, but it doesn't like to operate in tension. I suspect that the metal housing binds on the ball, as that is what captures the ball and keeps it all together. In compression it's smooth.

Bit of a trick to get the metal part off the ball, but overall it's as demonstrated. I wouldn't expect it to transmit a lot of force but for light applications it looks simple and easy to service, if needed.

Remember, this is a sample, not a production piece.

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