Understand the Working Principle of Hydraulic Pump and Its Classification

1. Working principle of hydraulic pump

The working principle of the hydraulic pump is that the movement brings about a change in the volume of the pump cavity, thereby compressing the fluid so that the fluid has pressure energy. The necessary condition is that there is a change in the sealing volume of the pump cavity.

A hydraulic pump is a hydraulic component that provides pressurized liquid for hydraulic transmission, and 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. Its cam is rotated by an electric motor. When the cam pushes the plunger to move upward, the sealing volume formed by the plunger and the cylinder is reduced, and the oil is squeezed out from the sealing volume and discharged to the required place through the one-way valve. When the cam rotates to the descending part of the curve, the spring forces the plunger downward to form a certain degree of vacuum, and the oil in the tank enters the sealing volume under the action of atmospheric pressure. The cam makes the plunger rise and fall continuously, the sealing volume decreases and increases periodically, and the pump continuously absorbs and discharges oil.

There are many factors affecting the service life of the hydraulic pump, in addition to the design and manufacturing factors of the pump itself, the selection of some parts of hydraulic piston pump related to the use of the hydraulic pump (such as couplings, oil filters, etc.), and the operation during the commissioning process are also related.

2. What are the classifications of hydraulic pumps?

Types of pumps in hydraulic system: 1. According to whether the flow can be adjusted, it can be divided into: variable pump and quantitative pump. The output flow of hydraulic piston pump can be adjusted according to the needs called variable pump, the flow can not be adjusted called quantitative pump. 2. According to the pump structure commonly used in hydraulic system, it is divided into three types: gear pump, vane pump and plunger pump.

Gear pump: small in volume, simple in structure, less strict on oil cleanliness, and cheaper in price; but the pump shaft is subject to unbalanced force, serious wear, and large leakage. Vane pump: divided into double-acting vane pump and single-acting vane pump. This kind of pump has uniform flow, stable operation, low noise, higher working pressure and volumetric efficiency than gear pump, and more complicated structure than gear pump. Plunger pump: high volumetric efficiency, small leakage, can work under high pressure, mostly used in high-power hydraulic systems; but complex structure, high requirements for materials and processing accuracy, high price, and high requirements for oil cleanliness. Piston pumps are generally used when gear pumps and vane pumps cannot meet the requirements. There are some other forms of hydraulic pumps, such as screw pumps, etc., but the application is not as common as the above three.