pic: Planetary...Wheel?

[Jeff Waegelin]

Originally Posted by Andy Brockway

Matt,

Is the ring gear attached to the wheel? If so, what forces the wheel to turn? Most planetaries will allow the moons to spin around the sun when the outer ring is stationary.

I suppose this will be cleared up when you post the exploded view. I believe you want the moons attached to the wheel with the outer ring fixed to the frame.

As I understand it, having seen the exploded view, the sun gear is on the motor output, the planets are stationary, and the ring gear is locked to the wheel. If I'm not mistaken, this setup will cause the ring gear to spin in the opposite direction as the motor, with a reduction equal to the number of teeth on the ring, divided by the number of teeth on the sun gear. Is this correct?

Over all, I was pretty impressed with this design. Matt showed it to me a few weeks ago, and I was considering using it in a summer project, though I ended up going in a slightly different direction. It seemed to me like a pretty easy, compact way to do a direct-drive gear reduction.