A11VO pump

First，Basic Overview

The A11VO pump is a high-pressure variable-displacement piston pump developed by Bosch Rexroth specifically for open hydraulic circuits in mobile machinery. It features a swashplate variable-displacement design, with standard displacement ranges in Series 1 from 40 to 260 cc/r; the version with a built-in makeup pump is designated as the A11VLO.

1. Core Positioning

Application Scenarios: Main hydraulic pump for construction machinery, featuring high power density, high efficiency, multiple control modes, and support for through-shaft pump series connection;

Circuit Type: Open-loop systems only (return to tank; distinct from closed-loop pumps A4VG/A6VM);

Key Advantages: Displacement continuously adjustable from 0 to maximum; externally adjustable constant power during operation; 100% through-shaft drive extension; and a variety of hydraulic and electronic control solutions.

Second，Internal Structure and Components

1. Drive Shaft Assembly: Delivers input power to drive the cylinder block rotation;

2. Cylinder Block + Piston Slipper Assembly: 9 sets of pistons; the slippers press against the swash plate to complete suction and discharge during rotation;

3. Swash Plate Variable Mechanism: Adjusts the swash plate angle to regulate piston stroke, enabling displacement variation from 0 to maximum;

4. Distribution Plate: Separates suction and pressure ports to distribute fluid;

5. Integrated Control Valve Block: Control valve assembly integrated into the top of the pump (combining DR/LR/EP/HD control functions);

6. Housing + Port Arrangement: Suction port, high-pressure discharge port, drain port, and pilot control port;

7. Optional: Built-in make-up pump (exclusive to the A11VLO series; provides low-pressure make-up, flushing, and improved suction).

Third，Typical Application Industries

1. Concrete machinery: Main pumps for concrete pumps, concrete mixer trucks, wet sprayers (A11VO130/190/260 LRDS are the mainstream models);

2. Earthmoving machinery: Loaders, road rollers, motor graders, mining loaders;

3. Lifting and Mining Equipment: Truck cranes, crawler cranes, rock drilling rigs, tunnel boring machines;

4. Road Maintenance Equipment: Asphalt pavers, milling machines;

5. Auxiliary Applications: Series gear pumps provide oil supply for steering, cooling, and pilot-operated multi-line systems.

Fourth，Key Usage Precautions

1. Suction resistance ≤ 0.8 bar; for high-displacement models, be sure to use larger suction filters and oil lines;

2. The drain port must return oil to a separate tank; do not allow pressure to remain in the system;

3. Recommended fluid: No. 46 anti-wear hydraulic oil; operating temperature range: -20 to +80°C;

4. Commissioning of constant-power models: Adjust for maximum displacement at idle and no load; ensure the engine speed remains stable under full load;

5. Prohibit prolonged operation at peak pressures exceeding 400 bar, as this will cause rapid wear on the distribution plate and pistons.

Fifth，Summary of Advantages and Disadvantages

Advantages

1. High pressure of 350 bar, capable of handling heavy-duty operating conditions;

2. Multiple control options cover the requirements of mechanically, hydraulically, and electronically controlled vehicles;

3. Through-shaft pump configuration simplifies the vehicle’s hydraulic layout;

4. Constant power output protects the engine and saves energy and fuel;

5. The swashplate design is compact and offers high power density.

Disadvantages

1. Compatible only with open-loop systems; cannot be used for closed-loop hydrostatic travel;

2. The 190/260 high-displacement models have weak self-priming capability; the A11VLO makeup pump version must be selected;

3. Maintenance parts require high precision; replacement parts must be matched to the original swashplate and plunger assembly.

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