Chuanna Hydraulic shares with everyone the types and working principles of hydraulic pumps

2025-07-30

A plunger pump is a power component of a hydraulic system, driven by an electric motor, which sucks in oil from a hydraulic oil tank, forms a pressure oil discharge, and sends it to the implementing component. Hydraulic pumps are divided into gear pumps, plunger pumps, vane pumps, and screw pumps according to their construction. Below, the editor will introduce the types of hydraulic pumps and their operating principles.

Types of plunger pumps

1. Piston pump: with a small volume, simple structure, and low requirements for oil cleanliness, the quotation is relatively cheap; But the pump shaft is subjected to unbalanced forces, severe wear, and significant leakage.

2. Vane pumps: divided into double effect vane pumps and single effect vane pumps. This type of pump has uniform flow rate, smooth operation, low noise, higher working pressure and volumetric power than gear pumps, and a more chaotic structure than gear pumps.

3. Piston pump: high volumetric power, small leakage, can operate under high pressure, mostly used in high-power hydraulic systems; But the structure is messy, with high demands for data and processing accuracy, expensive pricing, and high requirements for oil cleanliness.

Working principle of plunger pump

A pump is an energy conversion device that converts the rotational mechanical energy of an electric motor into hydraulic energy output. Hydraulic pumps operate based on the principle of sealing volume modification, hence they are commonly referred to as positive displacement hydraulic pumps or single plunger hydraulic pumps The plunger 2 in the figure is installed in the cylinder body 3 to form a sealed volume a, and the plunger is consistently pressed against the eccentric wheel 1 under the effect of the tension spring 4. The prime mover drives the eccentric wheel 1 to rotate, causing the plunger 2 to reciprocate and periodically change the size of the sealing volume a. When a increases from small to large, it creates some vacuum, allowing the oil in the tank to enter the oil chamber a through the one-way valve 6 on the suction pipe under atmospheric pressure, completing the suction process.