The wheel hydraulic excavator has the advantages of fast moving speed, no damage to the road surface, and long-distance transfer operation. Generally, the speed of the new gongzu wheel excavator is 20-35km / h, while the speed of the crawler excavator is 3-5km / h. when it needs frequent transfer operation, the wheel excavator shows its unique advantages and saves the transfer transportation cost. Increasing the traveling speed has become a trend in the development of wheeled excavators. The shifting device can reduce the speed and increase the torque, which can meet the requirements of vehicle speed and power output under working conditions and operation modes. The shifting mode of construction machinery depends on the structure and control mode of power transmission system.
The transmission system of wheel excavator has many forms: mechanical, hydro mechanical, full hydraulic pressure, electric drive, etc. The mechanical transmission system is composed of clutch, gearbox, universal joint, drive axle and final drive, while the hydro mechanical transmission system is composed of hydraulic torque converter (coupler) and power shift gearbox. Under the action of microcontroller, the shift clutch is controlled by shift multi way valve to form a step shift system. The whole hydraulic system is composed of pump, motor and final drive. The wheel side independent drive mode eliminates the gearbox, differential, drive axle and other structures. By changing the displacement of pump or motor, a stepless shift system is formed.