A New Take On The Cycloidal Drive (Extremely Compact)

Рет қаралды 31,884

Күн бұрын

Пікірлер: 50

@jakobheyn5585 4 жыл бұрын

This is really neat! What you have designed is a kind of differential gear, thats why the gear-ratio calculation is different from a two-stage gear. The first stage (1/10) and the second stage (1/9) are coupled at the input shaft; and by coupling them at the disks as well, you are getting the difference at the output: 1/10-1/9= -1/90. (During one input rotation, one stage moves 1/10 while the other moves 1/9 in the opposite direction.) I have seen differential gears designed with planetary gears, and some with cycloidal gears by fixing the two disks together. Your solution balances the the two disks, which is much better. Kudos!

@iandavis9565 5 жыл бұрын

Not the first to come up with this as a device, but you did an excellent job displaying the concept. The only thing presentation wise that would have been nice to show would be an exploded assembly view of it. Also, if you wanted to continue with an increased compact reduction, you can take this design concept and offset 120 degrees rather than 180 and make it a 3 stage reducer. The only thing with that though is the ability to back drive is diminished, and you start to pick up a little bit of backlash throughout the device just because of gear to lobe clearance that you need in real life. But good job on your drawing, now get out in the shop and build a physical one.

@Naxt366 3 жыл бұрын

Who was the first came up with that - And by what name does it come? I'd definitely want to see the evolved version.

@Rudmin Жыл бұрын

It’s frequently called a hypocycloid on KZbin. Commercially you can buy it under the Onvio Dojen product name.

@jonathanedelson6733 2 ай бұрын

A way to think about the value of this approach is that you trade contact patch velocity or pitch line velocity for compactness. In the compound approach that you describe, every point of contact on both disks experiences 90 nutations worth of travel per output rotation, while carrying the full force associated with the output torque. In a more conventional two stage approach, your output stage would only nutate 9x per output rotation, carrying the output forces. Your first stage would operate at high speed (90 nutations per output rotation) but would only carry a fraction of the output torque. So this compound stage would eliminate a bunch of bearing and be more compact, but would have higher losses and wear. All in all a good alternative to have in one's toolkit.

@kaden56 5 жыл бұрын

Awesome work man! This is indeed known as a two stage cycloidal drive. I saw a 3 stage one somewhere on KZbin that was nearly 1000:1 using this concept. Great design work!

@howardbartlett3419 4 жыл бұрын

This has been done before, but your specific execution of it is interesting. It is definitely something that would be cool to 3D print as a project.

@nero9248 6 ай бұрын

You made a cycloidal split ring gearbox, nice! This principle is usually a planetary gearbox design and was invented for compact radar gearboxes

@dekutree64 4 жыл бұрын

Awesome! I came up with a similar mechanism where the two discs are glued together, but it's kind of useless due to the vibration. This pin system is much better. The reduction formula for this family of mechanisms is 1 minus the ratio of the ratios. That is, 1 - (top disc lobes / top ring pins) / (bottom disc lobes / bottom ring pins) So the closer the top and bottom ratios are to eachother, the more reduction you get.

@treelibrarian7618 4 жыл бұрын

The math is simple: rotation 1 is 1/10 of shaft. rotation 2 is 1/9 of shaft in opposite direction. Subtract one from the other (1/9)-(1/10) = 1/90. [ fractional math: multiply top and bottom of both fractions to get same bottom, ie 10/90 and 9/90, then do subtraction of the tops (10-9)/90 ] Nice work, I've been working toward something like this myself, though with the purpose of removing the need for the drive pins. see James Bruce's comment and my reply

@mbunds 3 жыл бұрын

It sounds like the minimal difference in mass could easily be compensated by leaving some cavities in the heavier part. This is a brilliant design, but I wonder how much additional bulk would have to be added to bring it from the ideal design, to a practical one?

@snorttroll4379 Жыл бұрын

there would be vibration because it would vibrate on the transverse axis of the axis or something like that. it would be wobling. int a twisting way.

@GregorShapiro 3 жыл бұрын

Those narrow pins coupling the two cycloidal disks will not be able to withstand the great torque that the cycloidal teeth could deliver. Balancing this is not as simple at just having the same cross sectional area in the two gears (if made of the same material) as the disks are at different 'heights' or positions axially there will be a torque introduced in a plane parallel to that axis even if perpendicularly no or little torque would be induced.

@jamesbrown99991 4 жыл бұрын

There's basically the same thing here: kzbin.info/www/bejne/iXmXZ5WmmpaWhKM The difference is that you are using counter-wobbling internal gears (to stop the vibration), whereas the internal gears are fused in the linked video.

@The_GreenMachine 4 жыл бұрын

i tried making one of these and for some reason the output rotation is not smooth, it rotates as a wave; so it looks as if its rotating in steps. is there a reason for this? the input is smooth as butter, as is the 2nd stage input..

@wobblyjellyman69 5 жыл бұрын

Really cool man

@snorttroll4379 Жыл бұрын

link to the model? I want to make it and test it.

@gedr7664 4 жыл бұрын

did you end up exploring this further?

@piconano 3 жыл бұрын

Wouldn't the 2 holes cause the disk to snap in 2?

@kaleygoode1681 3 жыл бұрын

The input ring goes to the first gear... Shouldn't that be driving a ring to drive an output gear?🤔 (Like, flip the output ring and gear) Or is that aesthetic? Feels like torque is usually put ring to gear at each stage. I'm not a mech either🤷‍♀️

@cassandratom8986 4 жыл бұрын

Hi, If i am looking to make a cycloidal actuator with a 50:1 ratio. To reduce the vibration, I want to use 2 cycloidal gears, with 50 teeth each. Will this work? Or will there be no output?

@lesp315 4 жыл бұрын

Yes, you can do it. Also, you can buy Sumitomo cycloidal transmission on eBay and have fun with that.

@lesp315 4 жыл бұрын

I build one like that, but with bearings and housing and I'm using it on an electric bike. Works like a charm.

@BeyondFunction1 4 жыл бұрын

This kind of stuff breaks my brain. I just don't understand how you get that compounded reduction when both gears are being driven by the same shaft at the same speed.

@heartminer5487 3 жыл бұрын

think of a lever. you need two inputs (a pivot and a driver) to drive an output. in the case of a differential, the pivot is moving. in his design the input shaft is the moving pivot, and the pins from the lower gear are the driver. their difference drives the output (the topmost ring).

@viocudinti 5 жыл бұрын

Great work man! Do you have Patreon?

@LeviJanssen 5 жыл бұрын

I'm definitely not at that stage of my KZbin career, but I appreciate your support.

@skrebneveugene5918 5 жыл бұрын

@@LeviJanssen i ve even think about to register at patreon to support you

@jookehuang9089 4 жыл бұрын

so the most important thing is to balance the two disk?I'm not sure how to achieve it,could I just make the two disk the same weight ?

@jookehuang9089 4 жыл бұрын

I just saw another video about 2 stage cycloidal gear which was 3D printed .But the difference is he makes the top less lobe disk and the bottom one as one piece, he just dosen't use pins and holes like you says in this vedio.I'm curious about the designs between you guys, thank if you could reply.(⁎⚈᷀᷁ᴗ⚈᷀᷁⁎)

@serialdad33 3 жыл бұрын

jooke huang vi-de-o

@believeornot12 3 жыл бұрын

How about torque? will the pins able to hold the strength?

@samerboukaram2077 5 жыл бұрын

Very Nice, Is this back-drivable?

@LeviJanssen 5 жыл бұрын

I can’t say exactly, but I think it should be. Especially if all your contact surfaces are bearings.

@zachary3777 4 жыл бұрын

This reminds me of a Chinese windlass.

@snorttroll4379 Жыл бұрын

so make it. I want to see it.

@GoingtoHecq 4 жыл бұрын

maybe you could call it a compound cycloidal drive?

@kiwiwombatman 5 жыл бұрын

very cool !!

@akhilbarackal8427 4 жыл бұрын

Are there 2 gears for dynamic balancing ?

@matthewscott876 3 жыл бұрын

is this still reverse drive able?

@Sn0wZer0 4 жыл бұрын

Closest I've see is this video, which has a very similar differential-rate reduction with two sets of pins: kzbin.info/www/bejne/mZ-tdIqOZ9Olaq8 Yours is different in that the center lobes are offset for balance, but I do worry about the stacked tolerances vs a rigid center "lobe-set".

@treelibrarian7618 4 жыл бұрын

agreed, the fixed lobe-set in the centre seems better. I feel the weak-point of the standard cycloid gear is the output drive pins, and the single lobe-set addresses this. Balance can be restored without using a second offset gear-set by adding rotating offset weight directly to the motor shaft. I was close to this idea myself, thinking of a concentric system where the second gear is inside the offset gear and meshing with a second set of internal lobes, so the whole lot is in one plane.