A cycloidal reducer is a type of gear reducer. The essential operation is that an input shaft connects to and drives an eccentric bearing. This bearing additional drives a cycloidal disk (sometimes referred to as a cam) that connects to an output shaft.
cycloidal reducer
Usual cycloidal speed reducers, such as these Dojen series reducers from Onvio, provide zero backlash by combining a substance reduction cam with preloaded, complete compliment needle bearing cam followers.
The cycloidal disk (or cam) has lobes or teeth that build relationships some type of cam follower, typically a pin or needle bearings. The eccentric rotation of the cam is usually transformed into rotation of an output shaft at a reduced speed and an increase in torque.
The main benefit of cycloidal reducers is their house of zero or near-zero backlash, which Roots Vacuum Pumps results in high precision and high accuracy. That is especially in demand where highly precise and accurate positioning is required, for example in robotic applications, machine equipment, and comparable applications. Cycloidal reducers also feature rolling instead of 
sliding contact, therefore experiencing less overall put on.