Rexroth A4VSO High Pressure Constant Pressure DR Control Hydraulic Piston Pump for Industrial Hydraulic Station

Key Features

· Swash plate axial piston structure, DR constant pressure control

· Displacement infinitely adjustable via swash plate angle

· Nominal pressure: 350 bar, Max peak pressure: 400 bar

· Good suction performance, low noise operation

· Through-shaft design for multi-pump combination

· Modular construction, easy maintenance

· Visible swash plate angle indicator

· Compatible with mineral oil and some fire-resistant hydraulic fluids

Technical Parameters

Application Scenarios

· Hydraulic press / forging & stamping machine

· Metallurgical rolling equipment

· Injection molding & die casting machine

· Concrete pump truck, road construction machinery

· Mining crusher & drilling equipment

· Port crane & marine hydraulic system

· Large hydraulic power unit for heavy industry

Specifications:

Competitive Advantage:

1. This model is equipped with a built-in DR pressure compensator, which is a key differentiating feature. When the system reaches the set pressure, the pump will automatically reduce its displacement and stop continuously outputting excess flow, thereby reducing overflow heat. Compared to the constant-flow pump system, it saves energy by approximately 20%, provides better oil temperature control, and extends the lifespan of hydraulic oil and seals. The pressure adjustment response is fast and the pressure fluctuation is small.
2. The through-drive design allows tandem installation of extra pumps with one single motor, saving space and system cost. Standard flange, shaft and port configuration ensure high interchangeability. Easy installation, equipment upgrade and spare parts replacement for hydraulic system integrators.
3. Rated pressure: 35 MPa. The short-term peak pressure can reach 42 MPa. The internal spherical flow distributor structure is equipped with wear compensation, and the internal leakage increases slowly during long-term continuous operation. The 9-piston structure has low flow pulsation and low operating noise. The cast shell body is sturdy and can resist vibration and dust impact. It can operate continuously under heavy load for 24 hours and is suitable for various heavy industrial scenarios such as metallurgy, mining, large-scale injection molding, and hydraulic stations.

The Analysis of Common Faults of Liebherr A4VSO Open-Loop Axial Piston Pump:

1. One common failure of Rexroth A4VSO open-circuit piston pump is failure to build system pressure, resulting in weak load capacity and fast pressure drop. It is usually caused by contaminated hydraulic oil blocking the DR pressure compensator spool or damping holes, or heavy internal leakage due to worn piston slippers and valve plate. Air leakage on the suction line or clogged filter will also lead to insufficient oil supply, making heavy-duty equipment unable to work normally.
2. Abnormal noise and strong vibration represent another typical fault. The pump produces whistling or knocking sound during operation. Air entering the suction circuit causes cavitation. Worn bearings and swash plate assembly, together with improper oil viscosity, will worsen the situation. Continuous vibration accelerates internal wear and may damage pipelines and hydraulic valves, bringing secondary system troubles.
3. Excessive temperature rise is also frequently seen on A4VSO pumps. If the DR control unit malfunctions, the pump stays at large displacement continuously and generates massive heat from overflow. Internal leakage converts pressure energy into heat as well. High temperature ages seals and deteriorates hydraulic oil, which speeds up component wear and creates a vicious cycle.