1. According to whether the flow rate can be adjusted, it can be divided into variable displacement pumps and quantitative pumps. The output flow rate that can be adjusted according to needs is called a variable pump, and the flow rate that cannot be adjusted is called a quantitative pump.

2. According to the commonly used pump structures in hydraulic systems, there are three types: gear pumps, vane pumps, and plunger pumps.

Gear pump: Small in size, simple in structure, not strict in oil cleanliness requirements, and relatively cheap in price; But the pump shaft is subjected to unbalanced force, severe wear, and significant leakage.

Vane pumps: divided into double acting vane pumps and single acting vane pumps. This type of pump has uniform flow rate, smooth operation, low noise, higher working 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 in high-power hydraulic systems; But the structure is complex, with high requirements for materials and processing accuracy, expensive prices, and high requirements for oil cleanliness.