The structure of excavator includes power device, working device, slewing mechanism, control mechanism, transmission mechanism, walking mechanism and auxiliary facilities. The transmission mechanism transmits the power of the engine to the hydraulic motor, hydraulic cylinder and other actuating elements through the hydraulic pump to promote the action of the working device, so as to complete various operations. This article will briefly introduce the transmission system of excavator.
In the variable system, the most common is the dual pump dual loop constant power variable system, which can be divided into partial power variable and full power variable. The split power variable regulating system is to install a constant power variable pump and a constant power regulator on each circuit of the system, and the power of the engine is equally distributed to each oil pump. The full power regulation system has a constant power regulator that simultaneously controls the flow changes of all oil pumps in the system, so as to achieve synchronous variables. The return oil of the actuator in the open system flows directly back to the oil tank, which is characterized by simple system and good heat dissipation effect, but the oil tank has large capacity, there are many opportunities for the low-pressure oil circuit to contact with the air, and the air is easy to penetrate into the pipeline to cause vibration.
The operation of single bucket hydraulic excavator is mainly the work of oil cylinder, and the difference between large and small oil cylinder with cavity is large, the work is frequent, and the calorific value is large, so the vast majority of single bucket hydraulic excavator adopts open system. The oil return circuit of the actuator in the closed circuit does not directly return to the oil tank, which is characterized by compact structure, small oil tank volume, certain pressure in the oil inlet and return circuit, air is not easy to enter the pipeline, and the operation is relatively stable, avoiding the impact of reversing. However, the system is more complex and the heat dissipation conditions. The closed loop hydraulic system is also used in the slewing device and other local systems of the single bucket hydraulic excavator. In order to supplement the oil leakage caused by the forward and reverse rotation of the hydraulic motor, a makeup oil pump is often set in the closed system.
