cycloidal gearing question

[nmanousos]

Is there any reason besides tradition to use cycloidal gearing in a movement anymore? (The alternative being involute.)

[SIP6A]

nmanousos:

If you go to this link:

http://www.csparks.com/watchmaking/Cycl ... hoen.xhtml

It will give you a good history of cycloidal gearing. And make a case for as the author says "consign it to the dustbin of history"

Todd

[nmanousos]

Todd - thanks for the link! That helps a lot.

Nicholas

[Curtis]

Hi nmanousos,

Watchmaker extraordinaire, Andreas Strehler, offers the following information:

The referred text on the forum is right. Cycloidal gears are more efficient than involute gears when correctly made and positioned. Involute gears, even when perfectly made, always have a certain amount of efficiency losses. However, poorly made involute gearing won't get more inefficient, unlike cycloidal gears that will become more inefficient, worse than involute gearing, if poorly made and positioned.

In industrial made parts we need large tolerances to be economical. Involute gears are more appropriate because they maintain the same loss of energy, in all conditions, and have only small variations in transmitted power.

On the other hand we need to make the involute gears with a smaller module (pitch) to keep the same gear ratios. Smaller modules are more difficult to produce and they are more susceptible to wear than larger modules.

Cheers,

Curtis