Voice Coil Rotary Actuator

What is the application?

The objective is to move a metallic disk in a vane (a flap) with a very fast angular oscillation, the main axis of rotation being in the plane of the disk (not through it) - Max frequency of oscillations is around 300 Hz. Max Diameter of the disk is around 20 cm.

Sort-of like a bass loudspeaker, perhaps? Can anything of that nature be adapted?

Not at all. The displacement of the coil is not linear as it is with a subwoofer. Displacement is a +- angle around a resting position) and the rotational axis is in the plane of the disk. I.o.w.,oscillations are within a sector.

To give you an idea, here is a small sketch of the principle

I found something at KIMCO (California U.S) but it doesn't fit (not enough power) and hawfully expensive !

Thank you for your help anyway

Some sort of swashplate arrangement, and a rotary motion, from a motor, perhaps?

La Pression = l'argot pour 'beer"?

Yes, "Pression" in french means beer.

It comes from situations in a pub where beers are served directly from the tap (or pressure barrel)

translation is more or less

"Rather drink a "pression" than to be under pressure (to have "pression")

Cheers

Hi,

I have a feeling that your calculation is not correct, the torque should be much higher or the frequency or amplitude much lower.

Small scanners are available from General Scanning Inc. now part of a bigger company but you will find them.

Big scanners are not in use: no need (except very specialised in laser military use).

Small scanners are used for optical beam steering. Beam cross section often in the range from 1 to 10 mm. Frequency up to 1 ...5 KHz.

A fast and simple trial can be done with any DC, AC or stepper motor by switching back and forth.

Good and fast scanners are operated in resonance. This will give much lower power consumption. Lowered by the Q-factor of the resonant system.

RHABE

Thank you for your comment !

You're right as calculations with angular displacement +- 20° were done for a disk of 42 mm diam., not for the one of 20 cm.and the necessary torque (experienced) was 51 N.cm. I was using a brushless DC motor. It's working but the size of the motor was too large and inertia of the rotor was too important to reach 300 Hz.

Many thanks anyway for you info about General scanning. Interesting. I'll contact them

Well, torque X speed = power. The reason the size of the motor has to be large is 'cause the power density of ordinary machines (prime movers) is only so high.

The highest power rate I have run across in a motor had an ironless disc rotor.

Sounds like you just need a basic galvanometer movement...

Just like a normal meter movement but instead of a needle a small mirror is mounted on the shaft.

These were and still are used to measure extremely small current flows... In an Ultra violet chart recorder they have frequency ranges of many kilohertz.

John.

Gee Plus can supply voice coil rotary actuator. They are listed in Global Spec.

web site is www.geeplus.biz

Hi Jeanfifi,

Is it a market for such an actuator? What is made of the disc and the vane housing? And where are you located? Sorry to bother you with so many questions, but I might have a solution for you.

Regards

Not sure if this will help but a worm type drive with a 'follower' pin in a slot on the shaft of the vane will give you all the torque on the vane you need and you can spin the driving wheel at any speed from a motor to give you the frequency required.

This assumes you always want the same amplitude but with some mechanical inginuity you can adjust this too.

The power required as already explained is still required but you will be able to run the motor at a higher speed which will enable he use of an AC motor which could be smaller.

Many thanks to all of you for your help !

This forum is really great!

Yes, Hotttech, there is a huge potential market for this product. Unfortunatly, I can't disclose too much about the final product as it is in a patent process. But expected sales per year, on a mature market (Europe only), are in the order of 30 000. And we might go to U.S. through our joint venture Cy. That means cost of the actuator is a reel issue and it has to be very cheap considering this volume of sales.

Thanks Blueman for this reference. This, is very close to what i'm looking for but too expensive I think. I'll contact them

Yes, Bill, you're right, the most powerfull motor I tried was an axial field motor, with a disc rotor.

Sorry Toptekkie, but I didn't get exactly what you suggest§ Could you explain it again, please.

By the way. For those who are interested in, I'm french ...from SARKOZYLAND

There is a good company in France for this type of custom actuator. See MMT if the $ (€) is not too much of a problem.

I could recommend some others in the US.

On a les clowns qu'on élit... (We have the clowns we elect...)

A regular crankshaft is easier to build, and the amplitude can be controlled by the radius of the crank pin connection. As for the "all the torque on the vane you need" is concerned, that depends on the power of the prime mover and the strength of materials of the mechanism.

Hi gentlemen.

Again many thanks to all of you ! Special thanks to

Gigaconcept. THAT IS EXACTLY What I was looking for (as far as technology is concerned), and it can be found ...(shame on me!) in France! - So I can negotiate the costs more easily.

Congratulations also to Toptekkie for his very bright idea and his nice drawing. To be experienced (I will, for sure !!). This could lead to a very cheap solution. The question is how to control in real time the rotor speed to generate a variable frequency oscillation.

But in any case, there are brilliant guys on this forum .

JeanFiFi from SARKOCLOWNLAND

Transmets mes salutations à Didier Angleviel si il y est encore.

Bonne chance.