Types And Applications of Variable Displacement Piston Pumps

As the core power unit of hydraulic systems, variable displacement piston pumps have become indispensable in industrial automation and construction machinery due to their high efficiency, energy-saving capabilities, and intelligent control. This article provides an in-depth analysis of four mainstream types of variable displacement piston pumps, their technical features, and industry applications to guide precise selection.

1. Load-Sensing Variable Displacement Piston Pump: Energy-Saving Pioneer with Intelligent Tracking

Working Principle
Equipped with an integrated LS (Load Sensing) control valve group, it dynamically detects load pressure changes. When system pressure fluctuations exceed a set threshold (typically ±2 bar), the pump automatically adjusts its displacement (0–100%) to precisely match flow with load demand.

Technical Parameters

• Pressure response time: ≤50 ms

• Flow regulation accuracy: ±1.5%

• Typical energy efficiency: 35% higher than fixed displacement pumps

Application Scenarios

• Injection molding machine clamping systems (28% energy savings)

• Proportional control in aerial work platforms

• Hydraulic systems for marine rudders

2. Pressure-Compensated Variable Displacement Piston Pump: Pressure Guardian with Rock-Steady Stability

Control Features
Utilizes a PC (Pressure Compensator) valve group to maintain constant output within a 5–350 bar pressure range. Displacement resets to zero when system pressure reaches the set value, eliminating overflow losses.

Technical Advantages

• Pressure fluctuation rate: <±1.5%

• Overpressure protection response: <10 ms

• Typical energy consumption reduction: 25%–40%

Classic Cases

• Sany SY365 excavator main pump system

• Hydraulic stations for shield tunneling machine propulsion

• Metalforming presses in metallurgical equipment

3. Constant-Flow Variable Displacement Piston Pump: Precision Flow Master for Critical Processes

Innovative Design
Employs mechanical or electronic flow feedback mechanisms to maintain stable flow (0.5–200 L/min) with fluctuations controlled within ±2%. Ideal for scenarios requiring extreme flow stability.

Industry Benchmarks

• Eaton Vickers series: Medical device infusion systems

• Rexroth A10VSO: CNC machine tool cooling systems

• Huade HVP series (domestic): Food filling production lines

4. Electro-Hydraulic Variable Displacement Piston Pump: Intelligent Hub for the Digital Era

Technological Breakthroughs
Integrates proportional solenoid valves (frequency response ≥50 Hz) and CAN bus communication modules, supporting 0–10V/4–20mA multi-mode control. Enables closed-loop flow and pressure control via PID algorithms.

Performance Parameters

• Regulation resolution: 0.1% FS

• Communication protocols: J1939, EtherCAT

• Dynamic response: 5× faster than mechanical systems

Smart Applications

• 5G base station hydraulic temperature control

• Electro-hydraulic steering systems for new energy vehicles

• Industry 4.0 digital twin platforms