Torkdrive Cycloidal gear reducers have a rotating shaft

Torkdrive Cycloidal gear reducers have a rotating shaft of a motor (center) attached an eccentric cam (orange) that rotates feely inside a ball bearing; that bearing, in turn, is in the center of a sun gear (green) that rolls inside a fixed ring gear (blue). In the leftmost drawing, the cam is facing up, cycloidal speed reducers keeps the sun gear in contact with the top of the ring gear. As the motor shaft beg cins to rotate clockwise, the contact point follows this motion, and the sun gear rolls inside the ring. Because the circumference (C) of the rolling gear is smaller than that of the ring, any point on its surface will effectively slowly rotate counterclockwise.