Gearless Cycloidal Speed Reducer

run

number of drive holes

3

4

5

6

output speed: slower

faster

This Demonstration shows a cycloidal speed reducer, which consists of a stator (blue) housing three rotating parts: the input shaft with its eccentric cam (green), the cycloidal rotor (gray), and the output disc (red). The output disc has a number of pins (red) that fit inside the drive holes (yellow) in the rotor.

Substantial speed reductions can be achieved without the use of gears. The reduction obtained is equal to

1



R

r

-1

, where

R

is the inside radius of the stator and

r

is the radius of the rotor.