A hydraulic component that supplies pressurized fluid to a hydraulic drive. It is a type of pump. Its function is to convert the mechanical energy of power machines (such as electric motors and internal combustion engines) into liquid pressure energy. Output flow can be adjusted according to the needs of the variable pump, called the quantitative pump can not be adjusted. Hydraulic system commonly used pump gear pump, vane pump and plunger pump 3 kinds. â‘ gear pump: smaller size, simple structure, less stringent requirements on oil cleanliness, cheaper prices; but the pump shaft by the unbalanced force, serious wear and tear, leakage larger. â‘¡ vane pump: divided into double-acting vane pump and single-action vane pump. This pump flow uniform, smooth operation, low noise, work pressure and volumetric efficiency than the gear pump, the structure is more complex than the gear pump. â‘¢ plunger pump: high volumetric efficiency, small leakage, can work under high pressure, mostly for high-power hydraulic system; but the structure is complex, high precision materials and processing requirements, the price is expensive, the oil cleanliness requirements. Generally in the gear pump and vane pump can not meet the requirements of the plunger pump. There are some other forms of hydraulic pumps, such as screw pumps, but not as good as the above three kinds of universal.