This reducer is used for 5.5-6 ton crawler excavator. It transmits the rotation speed and torque output by the hydraulic motor to the large ring gear fixed to the frame, and drives the large ring gear to drive the rotary turntable to realize the excavator working platform. turn around. It adopts two-stage planetary gear reduction structure, hardened and ground gears and nitrided internal gears. It has the characteristics of compact structure, strong load carrying capacity, reliable operation, high transmission efficiency, small size and light weight.