A11VO40DR/10R-NSC12K01 Rexroth Pump 42cc 350bar DR Control

Product Overview

The A11VO40DR/10R-NSC12K01 (Material No. R902033547), A11VO40LRDH1/10R-NZC12K02 (Material No. R902046915), and A11VO40LRG/10R-NPC12N00 (Material No. R902220156) are Bosch Rexroth A11VO Series size 40 swashplate-type axial piston variable pumps, Series 10, with a nominal displacement of 42 cm³/rev. The A11VO series is Rexroth’s all-purpose high-pressure pump developed for hydrostatic drives in open circuit, designed primarily for mobile applications. Output flow is proportional to drive speed and displacement, with infinitely variable flow adjustment achieved by changing the swashplate angle.

The A11VO series features compact design, high power density, high efficiency, and low noise levels. The pump can operate self-priming or with an optional built-in charge pump (impeller pump). The universal through drive (100% through drive) allows tandem mounting of gear pumps and axial piston pumps up to the same size, providing flexible expansion for multi-circuit systems. The A11VO series offers a comprehensive range of control options including DR (pressure control), LR (power control), LRDH1 (power control with pressure cut-off), LRG (remote power control), and others, configurable to match specific machine requirements.

The three models differ in control type: A11VO40DR/10R-NSC12K01 features a DR hydraulic-mechanical pressure controller that automatically reduces displacement to maintain constant pressure when system pressure reaches the set value; A11VO40LRDH1/10R-NZC12K02 features LRDH1 constant power control with pressure cut-off, automatically reducing displacement along a constant power curve as system pressure rises while providing pressure cut-off protection; A11VO40LRG/10R-NPC12N00 features LRG remote power control, with the power setting externally adjustable via remote pilot pressure signal.

All products are manufactured to exact Rexroth OEM specifications, with mounting dimensions, flange interfaces, and port layouts fully consistent with original pumps for true drop-in interchangeability. Every unit undergoes 100% simulated operating condition testing before shipment.

Technical Specifications 

Common Specifications (A11VO40 Series):

• Series: Rexroth A11VO Series 10

• Pump Type: Swashplate axial piston variable pump, open circuit

• Nominal Displacement (Vg max): 42 cm³/rev

• Displacement Range: 0 – 42 cm³/rev (stepless variable)

• Nominal Pressure (pnom): 350 bar (5,100 psi)

• Maximum Pressure (pmax): 400 bar (5,800 psi)

• Maximum Speed (at Vg max): 3,000 rpm

• Theoretical Flow (3000 rpm, Vg max): 126 L/min

• Rotation Direction: Clockwise (R — viewed from shaft end)

• Mounting Flange: SAE 2-hole flange

• Through Drive: 100% through drive, suitable for tandem mounting of same-size pumps

• Housing Material: High-strength cast iron

• Weight: Approx. 32 kg

Model-Specific Parameters:

• A11VO40DR/10R-NSC12K01: Control type DR pressure controller, pressure setting range 50 to 350 bar, standard setting 250 bar. Clockwise rotation (R), N-series SAE flange ports. Material No. R902033547.

• A11VO40LRDH1/10R-NZC12K02: Control type LRDH1 power control with pressure cut-off, power setting externally adjustable even when pump is running. Material No. R902046915.

• A11VO40LRG/10R-NPC12N00: Control type LRG remote power control, power setting externally adjustable via remote pilot pressure signal. Material No. R902220156. All-purpose high-pressure pump for open circuit applications.

Key Technical Advantages

1. DR Pressure Control for Precise Constant Pressure Holding (A11VO40DR/10R-NSC12K01): The DR pressure controller is the defining technical feature of this model. The hydraulic-mechanical pressure controller senses system pressure via a pilot valve, with pressure setting range 50 to 350 bar (standard 250 bar). When system pressure reaches the set value, the control piston drives the swashplate to reduce its angle, and pump displacement automatically decreases to a level sufficient only to compensate for leakage, maintaining constant system pressure. This mechanism eliminates power waste and fluid heating in applications requiring prolonged pressure holding such as hydraulic presses and die-casting machines.

2. LRDH1 Power Control with Pressure Cut-Off (A11VO40LRDH1/10R-NZC12K02): The LRDH1 control integrates constant power control with pressure cut-off. The power control ensures pump output power does not exceed the prime mover’s available power, automatically reducing displacement along a constant power hyperbola as system pressure rises; the pressure cut-off function rapidly reduces displacement to zero when system pressure reaches the set value, providing safety protection. The power setting is externally adjustable even while the pump is running, providing operators with flexible on-site adjustment capability.

3. LRG Remote Power Control for Remote Adjustment (A11VO40LRG/10R-NPC12N00): The LRG control adds remote adjustment capability to constant power control. Via external pilot pressure signals, operators or machine control systems can remotely change the pump’s power setting, achieving power matching under different operating modes. This feature offers significant advantages in applications requiring power curve switching based on operating conditions, such as fine-operation mode versus high-efficiency mode in excavators.

4. Swashplate Variable Mechanism with Stepless Flow Adjustment: The A11VO40 series employs a swashplate variable structure, with output flow proportional to drive speed and displacement. Flow can be steplessly varied from zero to maximum by adjusting the swashplate angle. The swashplate is supported by high-stiffness bearings, maintaining precise angle control at 350 bar nominal pressure. The pump’s short displacement response time suits dynamic hydraulic systems requiring rapid flow switching.

5. Compact Lightweight Construction with Through Drive Flexibility: The A11VO40 weighs approximately 32 kg at 42 cm³/rev displacement, delivering an excellent power-to-weight ratio. The 100% through drive supports tandem mounting of gear pumps and axial piston pumps of the same size, providing flexible expansion for multi-circuit systems. The compact design saves installation space, suitable for mobile machinery with strict installation envelope requirements.

Application Areas

• Construction Machinery: Excavators, wheel loaders, cranes — main or auxiliary hydraulic systems

• Concrete Pumping Machinery: Concrete pump trucks, trailer pumps — hydraulic drive systems

• Road Construction Machinery: Road rollers, asphalt pavers, cold planers — travel drive systems

• Mining Machinery: Roadheaders, underground drilling rigs

• Forestry Machinery: Timber harvesters, forwarders

• Agricultural Machinery: High-horsepower tractors, combine harvesters

• Industrial Hydraulics: Various industrial equipment requiring high-pressure open-circuit hydraulic power

Expert Maintenance Tips

1. Shaft Alignment and Flange Connection: Concentricity deviation between the pump and drive shaft must be less than 0.05 mm, with angular deviation less than 0.25°. The A11VO40 uses an SAE 2-hole flange. Tighten flange bolts in diagonal sequence for even loading. Check that the original mounting base locating step is in good condition — repair the base before installing a new pump if worn.

2. Initial Start-Up Filling and Bleeding: Pre-fill the pump with clean hydraulic fluid through the case drain port before installation. Start at the lowest drive speed and observe a steady oil flow from the case drain port free of bubbles. Once bleeding is complete, gradually increase to working pressure.

3. Control Setting Verification: After pump replacement, verify the control settings match the original system using calibrated pressure gauges. The DR control pump has a pressure setting range of 50 to 350 bar (standard 250 bar), while the LRDH1 power setting and pressure cut-off values and the LRG remote power setting signal must be individually verified. Record the original settings before adjustment for restoration.

4. Rotation Direction Verification: This model is clockwise rotation (R — viewed from shaft end). Driving it counter-clockwise is strictly prohibited — incorrect drive direction will reverse the suction and pressure sides, causing severe rotating group damage within a short period.

5. Fluid Cleanliness and Viscosity Management: Use HL / HLP mineral oil with a viscosity range of 10–1,000 cSt. System filtration should achieve β10 ≥ 75. Replace filter elements after the first 500 operating hours, then every 1,000 hours or annually thereafter.

6. Through Drive Application Notes: When using through drive for tandem mounting of multiple pumps, ensure proper coupling alignment between pumps and verify that the combined drive torque does not exceed the front pump shaft’s load capacity. Consult factory technical support for combination configuration confirmation.