A planetary gearbox Cycloidal drive or cycloidal swiftness reducer is a system for reducing the speed of an insight shaft by a certain 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 within an eccentric, cycloidal movement. The perimeter of the disc is targeted at a stationary ring gear and has a group of result shaft pins or rollers placed through the facial skin of the disc. These output shaft pins straight drive the result shaft as the 
cycloidal disc rotates. The radial movement of the disc isn’t translated to the output shaft.