Bosch Rexroth Hydraulic Pump Working Principle

Hydraulic pumps from Bosch Rexroth convert mechanical energy (from an engine or motor) into hydraulic energy by generating flow and pressure. The working principle depends on the type of pump

1. Main Types of Rexroth Hydraulic Pumps

Rexroth produces three primary types of hydraulic pumps

Gear Pumps (Fixed Displacement) – Simple, robust, used in medium-pressure systems.

Vane Pumps (Fixed or Variable Displacement) – Efficient, medium-to-high pressure.

Axial Piston Pumps (Variable Displacement) – High-pressure, high-efficiency, used in demanding applications.

2. Working Principle of Each Pump Type

A. Gear Pumps (e.g., Rexroth G2, G3, AZPF Series)

How It Works

Two meshing gears (one driven, one idler) rotate inside a tight housing.

As teeth separate at the inlet, they create a vacuum, sucking in fluid.

Fluid is trapped between gear teeth and casing, then pushed to the outlet. 

Fixed displacement – Flow depends on gear size and speed.

Applications

Mobile hydraulics, lubrication systems, low-to-medium pressure systems. 

B. Vane Pumps (e.g., Rexroth PV7, PVV Series)

How It Works

A rotor with sliding vanes rotates inside an eccentric cam ring.

Centrifugal force pushes vanes outward, creating sealed chambers. 

As the rotor turns, chamber volume increases (suction) and decreases (discharge).

Can be fixed or variable displacement (adjustable cam ring).

Applications

Machine tools, industrial hydraulics, medium-pressure systems.

C. Axial Piston Pumps (e.g., Rexroth A10V, A4V, A7V Series)

How It Works

Multiple pistons are arranged parallel to the drive shaft in a cylinder block.

A swashplate (angled disc) controls piston stroke length.

Fixed swashplate → Fixed displacement. 

Variable swashplate → Adjustable flow.

As the shaft rotates, pistons move inout, drawing in and expelling fluid.

High-pressure capability (up to 500+ bar).

Applications

Construction machinery, presses, marine hydraulics, high-power systems.

3. Key Differences Between Pump Types

Feature Gear Pump Vane Pump Axial Piston Pump

Efficiency Low-Medium Medium-High Very High

Pressure Range Up to 250 bar Up to 300 bar Up to 500+ bar

Noise Level Noisy Moderate Quiet (if well-maintained)

Cost Low Medium High

Displacement Fixed Only Fixed or Variable Mostly Variable

4. Critical Factors in Pump Operation

- Inlet Pressure (Avoid Cavitation) – Ensure proper suction conditions.

- Fluid Viscosity – Must match pump specifications (e.g., ISO VG 46).

- Contamination Control – Use filters (5µm recommended).

- Correct Rotation Direction – Some pumps are uni-directional.

Need More Details on a Specific Pump

If you’re working with a particular Rexroth model (e.g., A10VSO, PV7, AZPF), let me know—I can provide

- Detailed cutaway diagrams

- Troubleshooting tips

- Performance curves

Would you like a deeper dive into variable displacement control mechanisms (e.g., pressure compensators, load-sensing) Let me know!

Elephant Fluid Power has dozens of standard parts and seal production workshops, We stock an extensive inventory of OEM & new aftermarket replacement piston pump parts for mobile and industrial applications. The piston pump spares include pumps from manufacturers such as Bosch, Vickers, Rexroth, Kawasaki, Hitachi, Denison, Linde, Komatsu, Sundstrand, Parker, Oilgear, and more.