Excavator Main Pump

Excavator main pump refers to the main hydraulic pump of an excavator. It is a crucial component of the excavator's hydraulic system, which converts the mechanical energy of the engine into hydraulic energy. The following is a detailed introduction:

First, Function: 

The main pump draws hydraulic oil from the hydraulic oil tank and delivers it as pressure oil to various hydraulic actuators of the excavator, such as the boom cylinder, arm cylinder, bucket cylinder, and swing motor, to provide power for the movement of the working device.

Second, Working Principle:  

1. Piston pump principle

Suction stroke: As the piston moves downward in the cylinder, the volume of the working chamber increases, creating a vacuum. This causes hydraulic oil to be sucked into the working chamber through the suction valve from the hydraulic oil tank.

Discharge stroke: When the piston moves upward, the volume of the working chamber decreases, which increases the pressure of the hydraulic oil. The high - pressure oil is then forced out of the working chamber through the discharge valve and into the hydraulic system's pipeline to supply power to various components.

2. Control mechanism

Flow control: The excavator's main pump is usually a variable - displacement pump. The swash plate or wobble plate inside the pump can change the angle. A larger angle means a larger displacement per rotation of the pump, increasing the flow of hydraulic oil. When the operator moves the control lever, the control system adjusts the angle of the swash plate or wobble plate according to the movement of the lever, thereby changing the output flow of the pump to meet the requirements of different working speeds.

Pressure control: The main pump also has a pressure - limiting mechanism. When the pressure in the hydraulic system exceeds the set value, the pressure - limiting valve opens, and part of the hydraulic oil returns to the oil tank, which limits the maximum pressure of the system to protect the components of the hydraulic system from being damaged by excessive pressure. In addition, through the load - sensing system, the pump can automatically adjust the output pressure according to the load of the actuator, so that the system can work efficiently under different load conditions.

Third, Common Types: 

There are mainly gear pumps, piston pumps, and vane pumps. Gear pumps are simple in structure and low - cost, but have lower pressure and flow accuracy. Piston pumps can achieve high - pressure and large - flow output, with high efficiency and good control performance, and are widely used in medium and large - sized excavators. Vane pumps have stable operation and low noise, but are less adaptable to high - pressure environments.

Fourth, Maintenance Considerations: Regular maintenance is required to ensure its optimal performance. It is necessary to prevent the entry of impurities to avoid wear and blockage of components, check for oil leakage, and monitor the oil temperature to prevent overheating. In addition, regular replacement of hydraulic oil and oil filters is also an important measure to ensure the normal operation of the excavator main pump.

Used hydraulic pumps for excavators

Excavator hydraulic pump