Hydraulic piston pump A11VO75 EP2D valve

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Product details

A11VO75 EP2D is an open‑circuit swashplate axial piston variable displacement pump manufactured by Rexroth of Germany. EP2D refers to the integrated electro‑proportional and pressure cut‑off control valve dedicated for this pump. As a core power unit for mobile hydraulic systems, it enables stepless displacement control via electrical signals and system pressure cut‑off protection, widely used in heavy‑duty high‑pressure construction machinery.

Model Code Explanation

- A11VO: Series of open‑circuit swashplate axial piston variable displacement pump

- 75: Nominal displacement of 75 cm³/r (theoretical maximum output flow per revolution)

- EP2: 24V electro‑proportional displacement control, accepting 0~10V or 4~20mA electrical control signals to linearly adjust swashplate angle and precisely regulate output flow

- D: Built‑in DR pressure cut‑off function. When system pressure reaches the preset value, pump displacement is forced to zero to provide high‑pressure overflow protection

Operating Principle of EP2D Control Valve

1. Electro‑proportional Flow Control (EP2)

An electrical control signal energizes the proportional solenoid to drive the pilot spool and adjust the supply pressure of the swashplate servo cylinder. The swashplate angle changes linearly from 0 to 100% corresponding to the control signal, allowing stepless adjustment of pump displacement between 0 and 75cc/r to match load flow demand with high energy efficiency.

2. Constant Pressure Cut‑off (Function D)

An integrated pressure feedback valve actuates when system load pressure exceeds the preset value, returning the swashplate to zero displacement. The pump stops delivering flow and only maintains system pressure, preventing excessive heat generation from high‑pressure overflow and protecting the hydraulic system and engine.

3. Integrated Structure

EP2D is a one‑piece valve assembly. The proportional solenoid, pilot valve, servo valve and pressure cut‑off valve are all mounted on top of the pump body without additional external control valves, featuring compact installation and fast response.

Key Technical Specifications

Basic Pump Parameters

- Nominal displacement: 75 cm³/r

- Rated operating pressure: 350 bar (35 MPa)

- Peak instantaneous pressure: 400 bar (40 MPa)

- Operating speed range: 600~2600 r/min

- Maximum output flow at 2200rpm: 165 L/min

- Drive type: 100% through‑drive, allowing series mounting of other hydraulic pumps

- Standard seal material: NBR; FKM high‑temperature resistant seals are optional

EP2D Control Valve Parameters

- Supply voltage: 24VDC (standard for construction machinery)

- Control signal: 0~10V voltage signal / 4~20mA current signal

- Regulation response time: ≤150ms

- Adjustable pressure cut‑off range: 250~350 bar, externally adjustable during operation

- Solenoid connector: DIN 43650 standard waterproof connector with IP65 protection

Structural Features

1. Swashplate piston design with high volumetric efficiency and stable performance under long‑term high‑pressure operation

2. Integrated EP2D control combines electrical flow regulation and pressure protection, simplifying hydraulic system design

3. External adjustment available for proportional flow gain and pressure cut‑off value to adapt to various load conditions

4. Excellent self‑priming performance; compatible with an integrated charge pump for poor suction conditions

5. High vibration and shock resistance, specially designed for mobile machinery including excavators, concrete pump trucks and pavers

Typical Applications

- Main hydraulic pumps for concrete pump trucks and mixer truck drive systems

- Construction machinery such as excavators, loaders, road rollers and pavers

- Heavy‑duty hydraulic equipment for mining, aerial work platforms and port machinery

- High‑pressure variable power units for large industrial hydraulic stations

Consumable Spare Parts

- EP2D 24V proportional solenoid

- Servo spool and pressure cut‑off spool

- Valve block seal kit and swashplate servo cylinder oil seals

I. Product Overview

TheA11VO75 EP2Dis a swashplate-type axial piston pump from the Rexroth series, serving as a core power component in hydraulic systems. Designed for open-circuit hydraulic systems, it achieves continuous adjustment of flow and pressure via its swashplate mechanism. It is widely used in construction machinery, agricultural equipment, industrial machinery, and other fields.

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II. Key Specifications

1. Displacement & Flow Rate

• Displacement:75 cm³/rev(theoretical value). Actual flow depends on rotational speed and volumetric efficiency.

• Flow range: Approximately189 L/min(theoretical) at rated speed (e.g., 2550–3000 rpm).

• Speed range: Typically1800–3250 rpm, adjustable based on operating conditions to prevent overheating or excessive wear.

2. Pressure Ratings

• Rated pressure:350–400 bar(varies by model variant, e.g., suffixes likeNZD12K04may affect pressure range).

• Peak pressure: Short-term tolerance to higher pressures is possible, but long-term operation should stay within rated limits for extended service life.

3. Control Modes

• Supports multiple control options, such asLR (pressure compensation),DR (remote pressure control), andEP2D (electro-proportional control).

• EP2Dindicates electro-proportional control, enabling precise adjustment of pump displacement or pressure via electrical signals (e.g., 0–10V or 4–20mA). Ideal for automation or closed-loop control applications.

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III. Structure & Materials

1. Main Structure

• Swashplate design with axially arranged pistons. Displacement is adjusted by varying the swashplate angle.

• The port plate and cylinder block use spherical oil distribution for automatic alignment, reducing leakage and wear.

2. Key Materials

• Cylinder block and pistons: High-strength alloy steel with surface hardening for enhanced wear resistance.

• Bearings: High-precision rolling bearings for radial load support on the drive shaft.

• Seals: Fluororubber or polyurethane materials rated for high-pressure hydraulic oil environments.

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IV. Applications

1. Construction Machinery

• Used in excavators, loaders, and road rollers to power hydraulic systems for travel, slewing, lifting, and other motions.

• Example: In excavators, theA11VO75 EP2Denables precise bucket control and compound operations via electro-proportional control.

2. Agricultural Machinery

• Powers hydraulic motors or actuators in combine harvesters and tractors, such as header lifting and steering systems.

3. Industrial Equipment

• Provides high-pressure hydraulic power for injection molding machines, die-casting machines, and machine tools, supporting rapid response and precise control.

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V. Performance Advantages

1. Energy Efficiency

• Variable displacement design matches pump output to load demand, reducing energy waste.

• Electro-proportional control (EP2D) enables closed-loop control for further system optimization.

2. Durability

• High-strength materials and precision manufacturing ensure reliable operation for10,000+ hours.

• Strong resistance to contamination, suitable for hydraulic oil with minor impurities.

3. Flexibility

• Supports multiple control modes for easy integration into existing hydraulic systems.

• The drive shaft allows tandem mounting of gear pumps or axial piston pumps for expanded functionality.

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VI. Maintenance & Troubleshooting

1. Routine Maintenance

• Replace hydraulic oil every1000–3000 hoursor6 months(refer to manufacturer guidelines).

• Monitor oil level and quality to prevent contamination or emulsification.

• Clean the radiator to prevent overheating.

2. Common Faults

• Insufficient flow: Check for clogged suction filters, low rotational speed, or internal leakage.

• Pressure fluctuations: Investigate control valve failures, abnormal oil viscosity, or pump wear.

• Abnormal noise: Inspect bearings, pistons, or port plates for damage, or check for air ingestion.

3. Repair Recommendations

• Use genuine OEM parts for seal or bearing replacements to ensure performance.

• Thoroughly clean the pump body before disassembly to prevent contaminant ingress.

• Tighten bolts to specified torque values during reassembly.