Hydraulic pumps


A hydraulic pump is an important hydraulic component that converts mechanical energy into hydraulic energy through the drive of an engine or electric motor. Specifically, the hydraulic pump draws the oil from the hydraulic oil tank, which then forms a pressure oil discharge to provide the required power to the actuators in the hydraulic system.


The working principle of a hydraulic pump is mainly based on the change in the volume of the pump chamber brought about by the movement, which compresses the fluid so that it has pressure energy. This process requires a change in the sealing volume of the pump chamber.


There are several ways to classify hydraulic pumps. According to whether the flow rate is adjustable or not, it can be divided into variable pump and fixed pump. The output flow of the variable pump can be adjusted as needed, while the flow rate of the fixed pump cannot be adjusted. According to the pump structure commonly used in hydraulic systems, it can be divided into gear pumps, vane pumps and piston pumps. The gear pump is small in size, simple in structure, and does not have strict requirements for the cleanliness of the oil, but it is seriously worn and leaks greatly. Vane pumps have uniform flow, smooth operation and low noise, but the structure is more complex than gear pumps. The piston pump has high volumetric efficiency, small leakage, and can work under high pressure, but the structure is complex and the price is more expensive.


The main components of the hydraulic pump include:

Pump Body: This is the main part of a hydraulic pump, usually made of metal material, which is used to house other components and form a sealed pump chamber.

Rotor or eccentric wheel: The rotor or eccentric wheel rotates inside the pump body, changing the volume of the pump chamber through its movement, thus sucking and draining the oil.

Plunger: The plunger is a key component of the piston pump, it reciprocates within the pump body, creating pressure by changing the sealing volume.

Cylinder block: The cylinder block is usually mated with the pump body to form a sealed pump chamber.

Bearings: Bearings are used to support the rotor and pump shaft, reducing friction and wear.

Seals: Seals are used to ensure the tightness of the pump chamber and prevent oil leakage.

Suction and drain valves: These valves control the inflow and outflow of fluid, ensuring that the hydraulic pump sucks in and drains the fluid at the right time.

Transmission shaft: The transmission shaft is used to connect the drive (such as an electric motor or engine) to the hydraulic pump to transmit power.

Center spring and swash plate (in some hydraulic pumps): These parts are used to control the movement of the plunger and the flow of the pump.


In addition, the hydraulic pump may also include other auxiliary components such as couplings, hydraulic tanks, etc. Couplings are used to connect the drive shaft to the pump drive shaft to ensure the correct transfer of power between the two. The hydraulic oil tank is used to store the oil and provide sufficient oil supply to the hydraulic pump.


Hydraulic pumps are used in a wide range of applications, including construction machinery, agricultural machinery, marine and aerospace. In these fields, hydraulic pumps are mainly used to drive various hydraulic actuators, such as hydraulic cylinders, hydraulic motors, etc., to achieve various complex actions and functions.


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