hydraulic system stations

Oil Pressure Pump Device

 

Anoil pressure pump deviceis a mechanical apparatus that converts mechanical energy into hydraulic energy. Its core function is to achieve oil suction and pressure delivery through the periodic change of sealed volume, thereby providing power for hydraulic systems. The following sections elaborate on its working principle, structural classification, application fields, and performance characteristics.

 

I. Working Principle

 

The fundamental operation of an oil pressure pump device revolves around the "periodic change of sealed volume." When the prime mover (e.g., an electric motor) drives the rotating components inside the pump, such as rotors, gears, or plungers, the sealed volume gradually expands, creating a negative pressure. This pressure differential causes hydraulic oil from the reservoir to overcome the suction valve and enter the pump, completing the oil suction process. As the rotor continues to rotate, the sealed volume gradually decreases, rapidly increasing the hydraulic oil pressure. When the pressure exceeds the system load requirement or the outlet valve's opening pressure, the outlet valve opens, and high-pressure hydraulic oil is delivered through the outlet to the hydraulic system, driving actuators (e.g., cylinders, motors). The continuous rotation of the rotor repeats the "expansion-contraction" cycle of the sealed volume, with the suction and outlet valves opening and closing alternately, enabling the continuous circulation of hydraulic oil.

 

II. Structural Classification

 

Based on the oil displacement mechanism and operating principles, oil pressure pump devices are primarily classified into positive displacement pumps and non-positive displacement pumps:

 

  • Positive Displacement Pumps: Equipped with mechanical separation devices, such as gears, vanes, or impellers, between the inlet and outlet to minimize internal leakage and slippage. Their output flow remains nearly unaffected by system pressure variations and includes fixed-displacement pumps and variable-displacement pumps. Fixed-displacement pumps adjust flow rate solely by changing rotational speed, while variable-displacement pumps can regulate displacement through mechanical or hydraulic means.

 

  • Non-Positive Displacement Pumps(e.g., centrifugal pumps): Lack distinct internal separation devices, resulting in reduced displacement as system working pressure increases due to internal slippage. However, these pumps provide a continuous flow, whereas positive displacement pumps exhibit intermittent (pulsating) flow characteristics. Pulsation can be smoothed using accumulators or system piping.

 

III. Application Fields

 

Oil pressure pump devices find widespread applications in industrial production, transportation, and daily life:

 

  • Construction Machinery: Provide power for the working devices and moving parts of heavy equipment, such as excavators, loaders, and cranes.

 

  • Automotive Industry: Serve as core components in braking and steering systems, enabling vehicle deceleration, stopping, and directional control.

 

  • Industrial Automation: Drive hydraulic motors and cylinders in robots, conveyor belts, and other equipment.

 

  • Marine and Aviation: Control hydraulic actions in propellers, rudder systems, and other critical devices.

 

  • Medical Field: Some precision medical devices (e.g., syringes) utilize hydraulic drives for accurate operations.

 

  • Energy Sector: Used for pressure control and safety protection in hydroelectric power stations and nuclear power plants.

 

IV. Performance Characteristics

 

  • Advantages of Positive Displacement Pumps: High flow stability, suitable for scenarios requiring precise hydraulic system control; flexible output through speed or displacement adjustment.

 

  • Characteristics of Non-Positive Displacement Pumps: Simple structure and lower cost, but flow is significantly affected by pressure, making them suitable for applications with less stringent flow stability requirements.

 

  • Common Advantages: Hydraulic oil transmission enables high power density, rapid response, and strong overload protection capabilities.