A planetary gearbox cycloidal drive or cycloidal acceleration reducer is a mechanism for reducing the swiftness of an insight shaft by a particular ratio. Cycloidal acceleration reducers are capable of relatively high ratios in small sizes. [1]
The input shaft drives an eccentric bearing that in turn drives the cycloidal disc in 
an eccentric, cycloidal movement. The perimeter of this disc is targeted at a stationary ring gear and has a series of result shaft pins or rollers positioned through the facial skin of the disc. These output shaft pins straight drive the result shaft as the cycloidal disc rotates. The radial motion of the disc isn’t translated to the output shaft.