The reducer plays a role in matching speed and transmitting torque between the prime mover and the working machine or actuator, and is a relatively precise mechanical device. The purpose of using it is to reduce the speed and increase the torque. It has a wide variety of types, different models, and different types have different purposes. There are many types of reducers, which can be divided into gear reducers, worm reducers, and planetary gear reducers according to the transmission type; According to different transmission stages, it can be divided into single-stage and multi-stage reducers; According to the shape of gears, they can be divided into cylindrical gear reducers, bevel gear reducers, and cone cylindrical gear reducers; According to the arrangement of transmission, it can be divided into expansion type reducer, diversion type reducer, and coaxial type reducer.