BOSCH REXROTH A4V Series Axial Piston Variable Pump

A4V Series Axial Piston Variable Pump

 

1. Product Overview

 

The A4V series is a world-famous swashplate type variable displacement hydraulic piston pump developed by Bosch Rexroth, designed for heavy-duty open circuit and closed circuit hydraulic system. This axial piston pump adopts high-strength cast iron housing and nine-piece precision piston assembly, featuring ultra-high pressure resistance, high volumetric efficiency and modular design. The displacement can be infinitely adjusted by changing the swash plate angle, which matches the power demand of host equipment automatically. It includes multiple sub-models: A4VSO (open circuit), A4VSG (closed circuit), A4VBO ultra-high pressure version, with displacement range from 40cc to 1000cc. Widely used in excavators, concrete mixers, concrete pumps, road rollers, mining machinery, metallurgical equipment and marine hydraulic systems. Standard SAE installation dimensions make it fully interchangeable with original OEM pumps and domestic replacement parts.

 

Model Code Explanation

 

- A4V: Series code of Rexroth axial piston pump

- Suffix O: Open circuit design; Suffix G: Closed circuit design

- Numbers: Nominal displacement (40,71,125,180,250,355 etc.)

- Control options: DR pressure control, DFR load sensing control, HS5 digital electronic control

 

2. Main Technical Parameters

 

Item Specification 

Pump Type Variable displacement swashplate axial piston pump 

Nominal Pressure 350 bar (35MPa) 

Peak Intermittent Pressure 400 bar (40MPa), A4VBO up to 45MPa 

Displacement Range 40 ~ 1000 ml/r 

Rotational Speed 600 ~ 2800 rpm 

Internal Structure Nine pistons, swashplate variable structure, through-drive available 

Standard Seals FKM fluororubber high temperature seals 

Applicable Fluid ISO VG46, VG68 anti-wear hydraulic oil 

Working Temperature -20℃ ~ +95℃ 

Volumetric Efficiency ≥94% under rated condition 

Control Modes Pressure control, load sensing, constant power, digital proportional control 

 

3. Working Principle

 

When the input shaft drives the cylinder block and pistons to rotate together, the pistons reciprocate along the swashplate surface. When pistons extend, oil is sucked from the inlet port; when retract, high-pressure oil is discharged into the hydraulic system. By adjusting the angle of the swashplate, the piston stroke changes, so the output flow can be steplessly regulated. The built-in control valve maintains stable system pressure and prevents overload damage for the hydraulic piston pump and actuators. The through-drive design allows mounting auxiliary gear pumps or charge pumps directly on the rear end.

 

4. Core Advantages

 

1. High pressure rating, stable performance under heavy load and frequent pressure impact.

2. Excellent suction performance, adaptable to high rotation speed working conditions.

3. Multiple control options to save energy and reduce system heat generation.

4. Modular construction, easy to replace control valves without disassembling main pump body.

5. Low noise design, small flow pulsation during continuous operation.

6. Good contamination resistance, suitable for harsh mining and construction sites.

7. Through-drive interface allows combined pump assembly to simplify system layout.

 

5. Application Range

 

This hydraulic piston pump is the core power component for heavy machinery hydraulic system, extensively fitted on concrete mixer trucks, concrete pumps, hydraulic excavators, pavers, compactors, mining loaders, metallurgical presses and deck machinery for ships.

 

6. Common Faults & Replacement Suggestion

 

Replace the whole pump assembly if symptoms appear: fail to build up pressure, slow actuator speed, serious external oil leakage, abnormal knocking noise inside pump, internal cross leakage leading to high oil temperature.