A11VO260LRU2/11R-NZD12K67VH Rexroth Variable Pump 350Bar

Product Overview

The A11VO260LRU2/11R-NZD12K67VH is a Bosch Rexroth A11VO series 11 swashplate-type axial piston variable displacement pump, nominal size 260, with a geometric displacement of 260 cm³/rev, purpose-designed for hydrostatic drives in open-circuit hydraulic systems. The pump operates on the swashplate principle, with output flow proportional to drive speed and displacement, infinitely variable between qV max and qV min = 0 through swashplate angle adjustment, at a nominal pressure of 350 bar and maximum pressure of 400 bar.

The full order code A11VO260LRU2/11R-NZD12K67VH decodes as follows: A11VO indicates the open-circuit swashplate variable pump series; 260 is the nominal displacement of 260 cm³/rev; LRU2 specifies power control with pressure cut-off — LR power control regulates the pump’s displacement depending on operating pressure so that a given drive power is not exceeded at constant drive speed, while U2 adds a pressure cut-off function that automatically de-strokes the pump to zero displacement when system pressure reaches the set value; 11 is the series designation; R indicates right-hand rotation (clockwise, viewed from shaft end); N specifies NBR nitrile rubber seals; Z specifies splined shaft; D12 specifies SAE 2-bolt mounting flange; K67 specifies shaft and special configuration codes; VH specifies special hardware feature codes.

The LR power control is the core control function of this pump — the controller regulates pump displacement based on operating pressure, ensuring that the pump does not exceed a given drive power at constant drive speed, operating along a hyperbolic characteristic curve for optimal power utilization. This control method is particularly suited to mobile machinery applications such as excavators and loaders requiring dynamic engine power matching.

Manufactured to exact Rexroth A11VO260 platform specifications, this pump delivers true drop-in interchangeability. Every unit undergoes 100% simulated operating condition testing before shipment.

Technical Specifications 

The following specifications are based on Bosch Rexroth A11VO series 11 official technical data (RE 92500) and publicly available product data:

• Model: A11VO260LRU2/11R-NZD12K67VH

• Manufacturer: Bosch Rexroth

• Series: A11VO series 11

• Design: Swashplate-type axial piston variable displacement pump, open-circuit

• Nominal Size: 260

• Geometric Displacement: 260 cm³/rev (15.87 in³/rev)

• Nominal Working Pressure: 350 bar (5100 psi)

• Maximum Working Pressure: 400 bar (5800 psi)

• Maximum Speed (Vg max): 1800 rpm

• Theoretical Flow at 1800 rpm (Vg max): 468 L/min

• Maximum Power (Δp = 350 bar): Approx. 273 kW

• Maximum Torque (Vg max and Δp = 350 bar): Approx. 1448 N·m

• Rotation Direction: Right hand (clockwise, viewed from shaft end)

• Control Type: LRU2 — Power control with pressure cut-off (LR power control + pressure cut-off)

• Mounting Flange: SAE 2-bolt flange (SAE J744)

• Shaft Specification: Splined shaft

• Seal Material: NBR nitrile rubber

• Through-Drive: 100% through-drive capability for adding gear pumps and axial piston pumps up to the same size

• Weight (Reference): Approx. 125 kg

• Housing Material: Cast iron

• Operating Fluid: Mineral hydraulic oil (DIN 51524 HLP)

• System Type: Open-circuit hydraulic system

Key Technical Advantages

1. LR Power Control for Dynamic Engine Power Matching

LR power control is the core control function of this pump. The controller regulates pump displacement based on operating pressure, ensuring that pump output power never exceeds the set drive power value. When system pressure rises, the controller automatically reduces displacement to maintain constant power; when pressure drops, displacement automatically increases. The pump operates along a hyperbolic characteristic curve for optimal power utilization, effectively preventing engine overload and stall. The power control option is externally adjustable, even while the pump is running. This control method is particularly suited to mobile machinery applications such as excavators and loaders requiring frequent power matching.

2. Pressure Cut-Off Function for System Safety

The pressure cut-off function (U2 code) in the LRU2 control provides overload protection for the system. When system pressure reaches the user-set cut-off value, the pump automatically de-strokes to near-zero displacement, delivering only the small flow required to maintain pressure and preventing system overpressure damage. The pressure cut-off setting should be below the maximum pressure of 400 bar and can be flexibly adjusted for specific operating conditions.

3. 100% Through-Drive Capability for Multi-Pump Systems

The A11VO series supports 100% through-drive capability, allowing same-size or smaller gear pumps and axial piston pumps to be connected in series at the rear of the pump for multi-pump common-shaft output. The universal through drive is suitable for adding gear pumps and axial piston pumps up to the same size — i.e., 100% through drive — extending hydraulic system flow output without increasing installation envelope. The LRC cross-sensing control can also maintain constant total power for two same-size A11VO pumps.

4. High Power Density and Compact Design

The A11VO260 delivers approximately 273 kW output power at 260 cm³/rev displacement and 350 bar nominal pressure, offering high power density with an overall pump weight of approximately 125 kg — a compact structure within its displacement class. The cast iron housing provides excellent rigidity and damping characteristics, maintaining stable volumetric efficiency and low-noise operation across the full pressure range. The pump can operate under self-priming conditions, or with an optional built-in charge pump (impeller) for higher speed requirements.

5. 100% Simulated Operating Condition Testing

Every pump undergoes a comprehensive factory test protocol: continuous operation at 350 bar nominal pressure to verify volumetric and total efficiency, 400 bar maximum pressure cycling to validate housing and seal integrity, and full-speed-range verification of displacement control linearity and LR power control response. Test documentation is supplied with each unit.

Application Areas

• Large Excavators: Crawler excavator main hydraulic pump — LR power control suits dynamic engine power matching requirements

• Wheel Loaders: Large loader implement and travel hydraulic drive systems

• Mining Equipment: Mine transport vehicles and underground LHD loader hydraulic drive systems — LRDS compound control can reduce fuel consumption by 20%–35%

• Cranes: Large truck crane main hydraulic pumps and auxiliary hydraulic circuits

• Concrete Pump Trucks: Boom hydraulic systems and pumping circuit hydraulic drives

• Industrial Hydraulic Power Units: Large presses and forging equipment hydraulic power systems

Expert Maintenance Tips

1. LR Power Control Setting Calibration and Verification

LR power control relies on precise matching of the controller along the hyperbolic characteristic curve. After pump or control module replacement, verify the power control crack pressure-to-displacement relationship at rated speed, confirming it falls within the factory calibration curve. The power control option is externally adjustable — before adjustment, confirm that the system maximum pressure limit is already set to avoid incorrect adjustment sequence causing system overload. Always lock the fixing nut after adjustment.

2. Periodic Pressure Cut-Off Function Verification

The pressure cut-off function in the LRU2 control should be verified for setpoint accuracy every 2000 operating hours. The pressure cut-off setting must never exceed the system maximum pressure of 400 bar. Pressure cut-off adjustment should follow the Rexroth official technical manual (RE 92500).

3. Mandatory Case Pre-Fill and Air Purging

After installation, fill through the highest case port with clean hydraulic fluid filtered to ≤10 μm until oil overflows. Open the bleed plug and run the pump at idle until bubble-free oil flows continuously. Do not apply load until the system is confirmed air-free. Dry starting will cause catastrophic wear to the slipper and swashplate friction pair within seconds — with larger displacement pumps, the larger slipper area accelerates dry-start damage.

4. Precision Control for Through-Drive Series Applications

When using through-drive to connect a rear pump, strictly control rear pump weight and coaxial precision, and verify total torque and speed matching. Concentricity deviation should be within 0.05 mm, with angular deviation not exceeding 0.5°. Excessive rear pump weight can cause bearing load imbalance — add support beneath the pump body if necessary.

5. Fluid Cleanliness and Viscosity Control

Maintain system cleanliness at NAS 9 or ISO 18/16/13 or better. Recommended operating viscosity is ISO VG 46 or VG 68, with an optimum range of 14–50 cSt. With the A11VO260’s large displacement and high system flow, filter clogging occurs relatively faster — strengthen filter differential pressure monitoring. Install a 10 μm nominal filtration element in the suction line; replace after the first 200 hours, then inspect or replace every 500 hours.