A11VO95LRDS Rexroth 350 Bar Axial Piston Pump

Product Overview

The A11VO95LRDS/10R-NSD12K02 is a Bosch Rexroth A11VO Series 1 variable axial piston pump designed for open-circuit hydraulic systems. It uses a swashplate design and has a nominal size of 95, corresponding to a maximum theoretical displacement of 93.5 cm³/rev. Bosch Rexroth specifies the A11VO family primarily for mobile hydraulic applications.

The exact configuration A11VO95LRDS/10R-NSD12K02 combines power control LR, pressure cut-off D, and load-sensing control S. The LR function regulates pump displacement according to operating pressure to maintain the required power envelope. The pressure cut-off function reduces displacement when the preset pressure is reached, while the load-sensing section adjusts pump flow according to actuator demand.

For replacement applications, the complete type code is critical. Matching only the A11VO95 displacement is insufficient because shaft configuration, mounting flange, rotation direction, service ports and controller configuration must also correspond to the original installation.

Our replacement engineering approach focuses on mechanical and hydraulic interchangeability, including dimensional matching, shaft and flange compatibility, control response and simulated operating-condition testing.

Important model clarification: although the original product title references A11V, A11VO, A11VLO and several displacement sizes, the Bosch Rexroth RE 92500 data sheet identifies the A11VO95 as an A11VO configuration. In the cited Series 1 documentation, the A11VLO with integrated charge pump is listed from size 130 upward, so A11VO95 should not be represented as an A11VLO pump without additional model-specific documentation.

Technical Specifications

• Manufacturer: Bosch Rexroth
• Series: A11VO Series 1
• Full Type Code: A11VO95LRDS/10R-NSD12K02
• Product Type: Variable Axial Piston Pump
• Design: Swashplate, variable displacement
• Circuit: Open circuit
• Nominal Size: 95
• Maximum Displacement: 93.5 cm³/rev
• Minimum Displacement: 0 cm³/rev
• Nominal Pressure: 350 bar
• Maximum Pressure: 400 bar, short-term, t < 1 s
• Maximum Speed at Vg max: 2350 rpm
• Maximum Speed at Vg ≤ Vg max: 2780 rpm
• Theoretical Maximum Flow: 220 L/min
• Theoretical Power at 350 bar: 128 kW
• Theoretical Torque at 350 bar and Vg max: 521 Nm
• Filling Capacity: 2.1 L
• Approximate Mass: 53 kg
• Rotation: Clockwise when viewed from the shaft end
• Seal Code: N, NBR with FKM shaft seal ring
• Shaft End: S, ANSI B92.1a-1976 / SAE J744 splined shaft
• Mounting Flange: D, SAE J744 four-hole
• Service Ports: SAE configuration with metric fastening threads
• Through Drive: K02, SAE J744 101-2 (B), 7/8 in, 13T, 16/32 DP
• Control: LRDS — Power Control + Pressure Cut-Off + Load Sensing
• LS Differential Pressure Range: 14–25 bar
• Standard LS Differential Pressure: 18 bar
• Recommended Operating Viscosity: 16–36 mm²/s
• Maximum Hydraulic Fluid Temperature: 115°C
• Minimum Normal Fluid Cleanliness: ISO 4406 20/18/15
• Maximum Case Drain Pressure: 1.2 bar above inlet pressure and not more than 2 bar absolute

The displacement, speed, flow, power, torque, filling capacity and mass values above are taken from Bosch Rexroth’s A11VO Series 1 RE 92500 technical data.

Key Technical Advantages

1. Integrated LRDS Control Architecture

The LRDS configuration combines three important control functions in one pump controller.

LR power control changes displacement as operating pressure changes, following the relationship pB × Vg = constant to prevent the required drive power from exceeding the configured setting.

Pressure cut-off overrides the power control when the configured pressure is reached and shifts the pump toward minimum displacement. Load sensing regulates pump displacement according to the pressure differential across the external sensing orifice and therefore matches pump flow to actuator demand.

2. High-Displacement 93.5 cm³/rev Platform

The A11VO95 provides a maximum theoretical displacement of 93.5 cm³/rev and a theoretical maximum flow of 220 L/min at its specified maximum speed and full displacement.

This makes the pump suitable for mobile systems requiring high flow without relying continuously on throttling losses.

3. 350 Bar Rated Pressure Capability

The A11VO family is specified for 350 bar nominal pressure and 400 bar maximum pressure. Bosch Rexroth defines the nominal pressure as the maximum design pressure at which fatigue strength is ensured, while the maximum pressure is permitted only for short-term operation.

For continuous-duty applications, system sizing should therefore be based on the rated operating pressure rather than the short-term maximum pressure.

4. Continuous Variable Displacement

The swashplate architecture allows displacement to vary continuously from Vg max to Vg min = 0. Pump flow is therefore directly related to displacement and drive speed.

This architecture is well suited to engine-driven mobile hydraulics where flow demand changes continuously during machine operation.

5. SAE Mechanical Interface

The specified configuration uses an SAE J744 mounting flange and SAE-type shaft arrangement, providing a standardized mechanical interface for compatible mobile equipment. The K02 through-drive configuration also enables a downstream pump arrangement within the manufacturer’s specified torque limits.

6. Contamination Control Is Critical

Bosch Rexroth specifies a minimum normal hydraulic-fluid cleanliness level of ISO 4406 20/18/15 and notes that cleaner hydraulic fluid increases functional reliability and service life.

For an LRDS-controlled pump, contamination control is particularly important because contamination can affect the internal control elements and cause abnormal controller behavior.

Application Areas

The Bosch Rexroth documentation describes the A11VO family as primarily designed for mobile applications.

Typical application areas include:

• Excavators
• Mobile cranes
• Construction machinery
• Drilling equipment
• Heavy-duty material handling machinery
• Mobile industrial equipment
• Multi-actuator open-circuit hydraulic systems
• Engine-driven load-sensing hydraulic systems

Final application suitability should be verified against engine power, operating pressure, pump speed, hydraulic valve architecture, LS circuit characteristics, shaft configuration and mounting dimensions.

Expert Maintenance Tips

1. Verify the Complete Type Code

Always confirm the complete configuration:

A11VO95LRDS/10R-NSD12K02

The LRDS controller, clockwise rotation, seal arrangement, shaft type, flange, service-port configuration and K02 through drive should all be checked against the original pump.

2. Maintain Correct Inlet Conditions

For the version without an integrated charge pump, Bosch Rexroth specifies an absolute inlet pressure at port S of 0.8–30 bar, with additional inquiry recommended for inlet pressures above 5 bar.

Suction-line restriction, undersized piping, excessive filter pressure drop and low reservoir level should be avoided.

3. Keep the Case Drain Unrestricted

Case drain back pressure must remain within the specified limits. Bosch Rexroth requires an unrestricted, full-size case drain line directly to the tank.

Incorrect case-drain routing can increase internal pressure and negatively affect shaft seals, bearings and the rotating group.

4. Maintain Hydraulic Cleanliness

After pump replacement or hydraulic-system overhaul, flush the circuit and verify filtration performance before commissioning the pump. This reduces the risk of abrasive particles and installation debris entering the controller and rotating group.

5. Verify the LS Differential Pressure

The LRDS load-sensing control provides an adjustment range of 14–25 bar, with 18 bar specified as the standard differential pressure setting.

The LS valve, sensing line and pump controller should therefore be evaluated as one hydraulic control loop rather than as isolated components.

6. Perform Full Simulated-Condition Testing

For replacement units, professional commissioning should include:

• Rated-pressure verification
• Peak-pressure verification
• Flow and displacement response testing
• Load-sensing response testing
• Pressure cut-off testing
• Rotation and leakage inspection
• Extended thermal running test