A cycloidal drive or cycloidal speed reducer is a mechanism for reducing the swiftness of an input shaft by a certain ratio. Cycloidal velocity reducers are capable of relatively high ratios in compact sizes. [1]

The input shaft drives an eccentric bearing that subsequently drives the cycloidal disc in an eccentric, cycloidal movement. The planetary gearbox 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 result shaft pins directly drive the output shaft as the cycloidal disc rotates. The radial motion of the disc isn’t translated to the output shaft.