1, according to whether the flow can be adjusted can be divided into: variable pump and quantitative pump. The output flow can be regulated according to the requirement. It is called variable pump, and the flow can not be regulated as a quantitative pump.

2, according to the commonly used pump structure in the hydraulic system, it is divided into 3 types: gear pump, vane pump and plunger pump.

Gear pump: small volume, simple structure, less stringent requirements for the cleanliness of oil and cheaper price; but the pump shaft is unbalance, serious wear and greater leakage.

Vane pumps are divided into double acting vane pumps and single acting vane pumps. The pump has the advantages of uniform flow, smooth operation, low noise, high pressure and volume efficiency, and higher gear ratio than gear pump.

Plunger pump: high volume efficiency, small leakage, working under high pressure, mostly used in high power hydraulic system; but the structure is complex, the material and processing precision are high, the price is expensive, and the cleanliness of oil is high.