Robot reducer has the characteristics of high precision, high rigidity, high load, high speed ratio, long life, low inertia, low vibration, low noise, low temperature rise, compact structure, simple installation, etc. At present, there are two main types of bearings used in the field of robot reducers. One is harmonic reducer bearings, and the other is RV reducer bearings.

Bearings, as one of the core components in the reducer, are divided into the following categories according to the reducer, crossed roller bearing , and flexible bearing for harmonic reducer, and angular contact ball bearing for RV reducer. Cross roller bearing for harmonic reducer contains four series, CSG(CSF) series, CSD series, SHG(SHF) series，SHD series, it is named according to the reducer type. Harmonic reducer flexible bearing's name is HYR. RV reducer bearing named RV.