Today, excavators mostly use hydraulic transmission and control. The engine provides power to drive the hydraulic pump to rotate. After the high-pressure hydraulic oil comes out of the hydraulic pump, it drives the traveling hydraulic motor, hydraulic cylinder, rotary motor and distribution valve for hydraulic transmission and control.
Hydraulic pump is the power source of excavator hydraulic system. It is an energy conversion device that converts mechanical energy into hydraulic energy. In the hydraulic excavator, the hydraulic pump is also the most faulty component, and once the hydraulic pump fails, it will immediately affect the normal operation of the excavator hydraulic system, or even can not work.
Excavator hydraulic pumps are mostly swashplate variable double hydraulic pumps. The so-called variable pump is that the displacement of the pump can be changed. It changes the stroke of the plunger by changing the swing angle of the swashplate, so as to realize the change of the oil volume discharged by the pump. The advantage of variable displacement pump is that within the regulation range, it can make full use of the power of the engine and achieve the effect of high efficiency and energy saving, but its structure and manufacturing process are complex.
The selection and installation of hydraulic pump includes series installation and parallel installation. Series pump and parallel pump are a kind of axial piston pump. The main difference is that they have different structural forms. From the displacement, they can be divided into quantitative pump and variable pump. Most of them are variable pumps on excavators. Here we only talk about variable pump.
1. Series pump
Most series pumps are swashplate piston pumps, which change the variable by controlling the inclination of swashplate. The utility model is mainly characterized by sharing a transmission shaft, compact structure, low cost and easy maintenance.
2. Parallel pump
Parallel pumps are mostly inclined shaft piston pumps, which achieve the purpose of variable by changing the angle of the cylinder block. The main features are complex structure, high cost and long service life.
