Cycloidal Drives [and a bit of philosophy]

[Michael GilliganParticipant @michaelgilligan61133]

MichaelG.

[MacolmParticipant @macolm]

Some car seats use only two teeth on the height adjustment control to get a suitable gear ratio. The two teeth are often just a loop of (springy) wire, arranged so that both teeth mesh in the intermediate positions to provide locking.

[MacolmParticipant @macolm]

[Nigel Graham 2Participant @nigelgraham2]

Interesting explanation of a drive type new to me. (Though I could have done with a bit less “philosophy”).

I wonder the true shape of the teeth, or lobes, in a fully-designed cycloidal gear-box.

His models, like Malcolm’s rack-and-pinion, seem to use the “knuckle” or “hollows-and-rounds” gear form – fine for demonstrating the principle but not real gearing.

Knuckle teeth were used in the long-past, for heavy, rough applications such as slow-moving winches, but they incur a lot of friction by rubbing rather than rolling action, and the velocity ratio varies within each tooth action.

So do the proper cycloidal gear-boxes use some sophisticated tooth form… if so, what?

[Nigel Graham 2]

On Nigel Graham 2 Said:

Interesting explanation of a drive type new to me. (Though I could have done with a bit less “philosophy”).

I wonder the true shape of the teeth, or lobes, in a fully-designed cycloidal gear-box.

[…]

So do the proper cycloidal gear-boxes use some sophisticated tooth form… if so, what?

Here you go, Nigel … If you can stomach the narration:

MichaelG.

[Harry WilkesParticipant @harrywilkes58467]

Interesting Michael

H

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