1, according to whether the flow can be adjusted can be divided into: variable pump and quantitative pump. The output flow can be adjusted according to the needs of the variable pump, the flow can not be adjusted, known as the quantitative pump.
2. According to the commonly used pump structure in the hydraulic system, it is divided into three types: gear pump, vane pump and plunger pump.
Gear pumps: Smaller in size, simpler in structure, less stringent in terms of cleanliness of oil, and cheaper in price; however, the shaft of the pump is subject to unbalanced forces, causing serious wear and leakage.
Vane pump: Divided into double acting vane pump and single acting vane pump. This pump has uniform flow, smooth operation, low noise, higher pressure and volumetric efficiency than gear pumps, and a more complex structure than gear pumps.
Piston pump: high volumetric efficiency, small leakage, can work under high pressure, mostly used for high-power hydraulic system; but the structure is complex, the material and processing precision are high, the price is expensive, and the cleanliness of the oil is high.
The plunger pump is generally used when the gear pump and the vane pump cannot meet the requirements. There are some other forms of hydraulic pumps, such as screw pumps, but applications are not as common as the above three.