Bosch Rexroth A11VO145 Swashplate type Axial Piston Hydraulic Pump

Unlike bent-axis pumps (such as Rexroth's A2FO series), the swashplate-type A11VO uses a rotating group that tilts a swashplate to vary the piston stroke. This design offers three distinct benefits:

Compact footprint: The inline layout fits into tight engine compartments.

Fast response times: Swashplate inertia is lower than rotating the entire cylinder block.

Simple load-sensing integration: The servo piston can react to pressure taps in milliseconds.

The "145" in A11VO145 refers to the nominal displacement of 145 cm³/rev. At 2,000 RPM and 350 bar continuous pressure, this pump can theoretically move over 480 liters per minute. In practice, volumetric efficiency hovers around 95–97% for the first 8,000 operating hours.

Material Choices That Prevent Catastrophic Failure

Rexroth uses a through-drive shaft with FAG or SKF tapered roller bearings rated for 10,000-hour B10 life. The cylinder block is a copper-iron alloy (CuSn10Zn2) that embeds lead for break-in lubrication. The valve plate is nitrided steel, not bronze—this mismatch is intentional. It reduces adhesive wear during cold starts when oil viscosity exceeds 1,000 cSt.

Control Systems You'll Actually Use (LR, LRDS, and HD)

Most pump failures are control failures—not rotating group failures. The A11VO145 accepts several control variants, but three dominate.

Load Sensing (LRDS) – The Gold Standard

The LRDS control combines load sensing with pressure cutoff. A small orifice in the control spool compares pump pressure to the highest load signal (usually from a directional valve). The delta-P maintains a fixed margin (typically 14–22 bar).

Constant Power (LR) – For Tractor PTOs

If your prime mover is an internal combustion engine with a limited torque curve, the LR control prevents stall. As pressure rises above the threshold (say 250 bar), the pump reduces displacement proportionally. This keeps power constant at 90–110 kW depending on the setting.

HD Control for Two-Pump Systems

On excavators with twin A11VO145 pumps (one per track), the HD (hydraulic, displacement-controlled) variant allows negative flow control. A pilot pressure signal from the joystick increases swashplate angle. This is simpler than electronic closed-loop—and still common on Tier 3 machines.

Common Failure Modes and Expert Fixes

Even a premium pump fails when the system is neglected. Here is what I've seen in 20+ years of field service.

The "Slow Response" Trap

Symptom: Pump takes 0.8–1.2 seconds to destrokes when you release the lever.

Root cause: Servo piston bore wear (aluminum housing) or a blocked 0.8 mm orifice in the LRDS valve.

Fix: Replace the control valve block first—cheaper than pulling the pump. If that fails, measure servo piston clearance (max 5 µm).

Case Drain Flow Above 12 L/min

New A11VO145 case drain is <5 L/min at 300 bar. At 15 L/min, the rotating group is failing.

Expert note: Do not just increase the drain line size. Check the copper plug in the valve plate centering pin—it erodes asymmetrically on machines with frequent pressure spikes (e.g., demolition shears).

For more information on the A11VO145 hydraulic pump, please visit https://www.baolilaihydraulic.com/.

Specifications

Selection Table

Q1: What is the correct oil for cold climates?

A1:Use ISO VG 32 synthetic (e.g., Shell Tellus S4 VX 32) below -20°C. The pump will start without cavitation. At -30°C, standard mineral oil becomes too thick for the servo piston to actuate.

Q2:My pump vibrates at mid-stroke. Is that normal?

A2:No. Mid-stroke vibration (around 50–70 cm³) usually indicates the swashplate cradle bearing has a flat spot. Remove the servo piston cover and check for brass particles in the drain oil.

Q3:How to purchase an A11VO145 hydraulic pump?

A3:You can visit https://www.baolilaihydraulic.com/contact/ to contact us and purchase our products through various methods.

Q4:What is the price and delivery time of the A11VO145 hydraulic pump?

A4:The specific price and delivery time will be provided based on the specific model you provide.