The Structure Of A Plunger Pump

Plunger pumps are generally classified into single plunger pumps, horizontal plunger pumps, axial plunger pumps and radial plunger pumps.

Single Piston Pumps

These pumps feature a simple yet effective design composed of an eccentric wheel, plunger, spring, cylinder block, and two check valves. As the eccentric wheel rotates, it drives the plunger up and down within the cylinder block hole, creating a sealed volume that alternately draws in and discharges oil. The amount of oil displaced per revolution—known as displacement—is determined solely by the pump's structural parameters, ensuring consistent performance.

Horizontal Piston Pumps

Designed with multiple plungers (typically 3 or 6) arranged side by side, these pumps use a crankshaft mechanism—either through connecting rods and sliders or directly via an eccentric shaft—to drive reciprocating motion. This enables efficient suction and discharge cycles, making them ideal for high-volume fluid transfer applications. These pumps also incorporate valve systems that ensure smooth operation and reliable flow control.

Axial Piston pump

This pump in which the reciprocating motion of the piston or plunger is aligned parallel to the center axis of the cylinder block. This motion creates changes in volume within the piston chamber, enabling efficient suction and discharge of hydraulic fluid. Due to the cylindrical design of both the plunger and plunger hole, these components can be manufactured to extremely tight tolerances, resulting in minimal internal leakage and excellent volumetric efficiency—key advantages for high-pressure applications.

Straight-Axis Swash Plate Piston Pumps

These pumps are categorized into two main types: pressure oil supply type and self-priming oil type. Most pressure-fed systems operate with air-pressurized oil tanks to ensure stable hydraulic fluid delivery. It is crucial that the hydraulic oil tank reaches the required operating air pressure before starting the machine.

Failure to achieve adequate air pressure prior to startup may result in the sliding shoes inside the pump being pulled off, leading to abnormal wear of the internal return plate and pressure plate. This can significantly reduce pump lifespan and system performance. Our pumps are designed with enhanced structural integrity and wear-resistant materials to minimize such risks and ensure long-term reliability.

Radial Piston Pumps

Radial piston pumps are primarily divided into two types: valve distribution and shaft distribution.  Thanks to their structural advantages, fixed shaft distribution radial piston pumps offer greater resistance to shock loads, longer operational life, and improved control accuracy compared to traditional axial piston pumps.

In variable displacement models, the variable plunger and limit plunger adjust the eccentricity of the stator to achieve precise stroke control. The maximum stator eccentricity ranges between 5–9mm, depending on displacement requirements, allowing for very short yet highly effective stroke adjustments.

The variable mechanism is specifically designed for high-pressure operation and is controlled via a dedicated control valve, enabling fast response times. Additionally, the radial design effectively eliminates issues such as uneven wear on sliding shoes commonly found in axial piston pumps, significantly enhancing impact resistance and overall reliability.