Talk:Cycloidal drive

Uses?

Fascinating device. I'd love to know what it's actually used for, though. Some real-world uses would be a great addition. — Preceding unsigned comment added by 24.19.100.164 (talk) 21:49, 15 August 2012 (UTC)

Problems with this page

I came to this page from Wikipedia:Deadend pages with the intention of cleaning it up, but there's way more that needs to be done. It would seem that a Cycloidal Drive is a means of shaft speed reduction, while a Cycloidal prop or propellor is another name for a Voith-Schneider drive. The two items are not even close. Also there is now an aircraft version of the propulsion method, see here [[1]]. So I'm gonna write up the speed reduction, and point to Voith-Schneider for the means of propulsion. Scottanon 02:33, 31 December 2005 (UTC)

Expanded on speed reduction, added diagrams --Petteri Aimonen (talk) 19:50, 4 September 2009 (UTC)

A shame in the german wiki aswell :/ [2] Greets n happy new gear to u all! --92.225.111.100 (talk) 14:14, 27 December 2009 (UTC)

There are a couple of improvements that could be made with the 'Theory of operation' section. Particularly:

• the first sentence is not overly clear, and cycloidal drives are much more similar to harmonic drives in topology than planetary drives. doi:10.1115/1.4024370
• The number of pins on the ring gear does not need to be larger than the number of pins on the cycloidal disc. It depends if it is an epitrochoid design or a hypotrochoid design.

I plan to revise this section accordingly. Jon.sensinger (talk) 21:43, 12 September 2013 (UTC)

The article mentions the ring gear and ring gear pins. I can't tell what refers to based on the diagrams. So the equation relating ratio to ring gear pins and cycloidal disc lobes is useless to me.162.246.139.210 (talk) 19:07, 20 November 2023 (UTC)

Disadvantages

I disagree that cycloidal drives are non backdrivable. It is true that they have normal stiction and large torque ratios, and that the combination of these two produces larger than normal backdrivable torques compared with spur gears or planetary gears. However, unlike worm gears, which are inherently non backdrivable, cycloidal drives are easily back driven once a torque is applied above this amplified stiction torque. In this sense the backdrivable torques are consistent with Harmonic Drives, which also have large gear ratios and normal stiction. I have published a paper demonstrating that they are backdrivable. In addition, I have been contacted by a company asking why the Wikipedia page says they are non-backdrivable, since their own cycloidal drives are easily back driven. I plan to substantially revise this claim, as well as to add several other disadvantages described in my article (non-constant gear ratio, backlash, etc...). http://dx.doi.org/10.1109/ICRA.2012.6224739. Jon.sensinger (talk) 21:33, 12 September 2013 (UTC)

I disagree that the non backdrivable nature of the cycloidal drive is a disadvantage. I would call it a feature. — Preceding unsigned comment added by 69.174.58.156 (talk) 14:06, 27 March 2013 (UTC)

link

a good visualization [3] —Preceding unsigned comment added by 69.136.72.16 (talk) 01:24, 28 January 2010 (UTC)

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Backdriveability of Cycloidal drives

Hello together, usually, I am not editing the English Wikipedia, instead, I spend my time at the German Version. In the German Wikipedia article (Zykloidengetriebe), there originally was the information that Cycloidal drives can be backdriveable. Then, a user read in the English Wikipedia that they aren't and asked for a validation of this sentence on dewiki. I have found the following sentence in a Mechanical Engineering book: Cyclo-Getriebe sind nicht selbsthemmend, es ist auch eine Übersetzung ins Schnelle möglich, which means: Cycloidal drives are not self-retentious, a transmisson from slow to fast is possible, too. The data on that book are: Georg Jacobs: Maschinengestaltung Band II. Verlag Mainz, Aachen 2016, ISBN 978-3-86130-749-5, p. 247f. Its a book written in German, however, the three major manufacturers of Cycloidal drives are Sumitomo, Nabtesco and Nidec-Shimpo. These companies are all from Japan, so I do not think that Cycloidal drives in Germany somehow differ from those in English-speaking countries. Moreover, an IP user remarked some doubts on that issue a few years ago on this talk page. @Andy Dingley: You have reverted my edit, can you provide some sources why you think that Cycloidal drives are generally not backdriveable? Maybe it would help German Wikipedia, too. Greets, --EveryPicture (talk) 18:54, 5 July 2016 (UTC)

The contested edit is this and the text, "Unlike many other drive mechanisms the cycloidal drive is not typically backdrivable." I restored this with the summary, "Not typically backdrivable" is accurate, reasonable and useful. I would still stand by this.

Cycloidal drives are not, in general, backdrivable. I have never seen one that is. I have never seen a catalogue listing one. The problem is that their torque efficiency in this direction is minimal. I still fail to see what use one would have.

It is an obvious truth that "the cycloidal drive is not typically backdrivable" and it is appropriate to include this in the lead as such. Even if there is some unusual drive out there which does, it would still be unusual. An encyclopedia should explain the typical case and general principle before, if ever, covering the obscure.

You describe me as "a user read in the English Wikipedia" as if I know nothing of cycloidal drives and had just happened across this article moments earlier; I'm the guy who designed and made some of the machines linked from this article. I know just a little of the theory of cycloidal drive design.

The main point though is that your sourcing from the German wikipedia still says nothing about cycloidal drives being backdrivable: it says they "are not self-retentious", i.e. not self-locking. This is not the same thing! It is well known that a cycloidal drive does not well inherently resist a force on the output shaft (as a worm drive can do), although it can do if the input torque is maintained. This is what your self-retentious means. This is still not the same as backdrivable, meaning that the drive can be used by driving the slow-speed (output) shaft and using the high-speed shaft as a driven output shaft. If one tried this, the useful output torque would be negligible. Andy Dingley (talk) 23:54, 5 July 2016 (UTC)

I think I get your point. One thing left: The sentence "a user read in the English Wikipedia" did not mean you but a German user. That German user coincidentally read the English article and then he started a discussion on the German Wikipedia. He claimed that the sentece about retention in the German Wikipedia would be incorrect because of the sentence about backdriveability on the English Wikipedia. But I think now we have solved the problem. Greetings, --EveryPicture (talk) 12:06, 6 July 2016 (UTC)

More on back driveability

It is now 2022 and since the 2016 back drivability discussion, there is now nothing on back driveability in the article.

There is nothing in inherent in the design of cycloidal drives which prevents them from being back driven. In fact there are examples in robotics where this capability is used to provide controlled elasticity of the drive. There may be commercial products which are not designed for back driving, which may include differences in the design which prevents back driving, but I propose to add something on this with sources.Lkingscott (talk) 06:07, 25 September 2022 (UTC)

My interest in cylcoidal drives is amateur but I work with people in the mechanical power transmission industry. Through work I recently attended a tour of a Sumitomo assembly facility in Surrey, BC, Canada, and recalled seeing the discussion on this page. I asked the Sumitomo rep if cycloidal drives are back-drivable. He conferred with the shop supervisor, and they agreed that their cycloidal drives are back-drivable if the reduction ratio is less than 60. I reckon that this threshold isn't set in stone, but will vary between product lines, as I think it's basically a question of how friction losses cascade through the system.

I know that this is anecdotal and so won't meet any sort of evidential standard to qualify as a source but I thought it might help explain some of the inconsistency online. 107.190.29.74 (talk) 17:46, 23 January 2023 (UTC)

ring pins output efficiency

Why nobody talks about it. i think this gearbox may be simplied and used bolts that connect its gearbox to motor as axles for rollers (that uset for output for standart type gearbox). I think its usable for inside a chainwheel gearbox in toy tank, mars rover wheel, crawler or legged robots Daniskun (talk) 01:12, 9 January 2024 (UTC)