For mass consumers, the current terminal price of humanoid service robots is still relatively high, which has become the biggest obstacle affecting their popularization. Among them, core components such as reducers and servo motors have high manufacturing costs and are monopolized by foreign countries, which has become a shortcoming of my country's robot industry.

The reason why humanoid robots can achieve complex combined actions is to rely on small, intelligent, high-strength flexible joints. The core component is the reducer, which accounts for 70% of the cost of the robot, and the bearing is the key part of the reducer.

The robot reducer has the characteristics of high precision, high rigidity, high load, high speed ratio, high life, low inertia, low vibration, low noise, low temperature rise, compact structure, and simple installation. 

Currently, there are two main applications in the field of robot reducers. There are two types, one is harmonic reducer and the other is RV reducer.

As one of the core components in the reducer, bearings are also divided into the following categories according to the reducer, namely crossed roller bearings for harmonic reducers, 

flexible bearings for harmonic reducers, and angular contact ball bearings for RV reducers. There are four series of crossed roller bearings for harmonic reducers, CSG (CSF) series, 

CSD series, SHG (SHF) series, and SHD series. The naming method adopts the name of the reducer; the flexible bearing for harmonic reducer is named HYR , The main bearing of the RV reducer is named RV.