ZX130 is a medium-sized hydraulic excavator produced by Hitach. In this excavator, Final Drive is a key component. Its main function is to transfer the power generated by the hydraulic motor to the crawler to drive the excavator to move. The working principle of the final drive can be divided into the following steps: 1. **Hydraulic motor output**: The hydraulic pump in the hydraulic system converts the power of the engine into high-pressure oil, which is then transported to the hydraulic motor through the oil pipe. After the hydraulic motor receives this high-pressure oil, it converts the pressure energy into rotational motion. 2. **Deceleration and torque increase**: The output shaft of the hydraulic motor is connected to the final drive. In this process, the final drive usually includes one or more gear sets to reduce the speed and increase the torque. This is because the crawler requires a large torque to overcome the ground friction and load, and the higher speed is not suitable for the crawler. 3. **Power transmission to crawler**: The power after deceleration and torque increase is finally transmitted to the crawler of the excavator. The crawler tracks are in contact with the ground, and the friction between the teeth and the ground is generated, thereby pushing the excavator forward or backward. 4. **Steering control**: The steering of the excavator is achieved by adjusting the speed difference between the left and right final drive devices. When the speed of one