A4VG56EZ2DM1/32R-NSC02FC13SH Rexroth A4VG Piston Pump 400 Bar

Product Overview

Technical Specifications

• Full Model Number: A4VG56EZ2DM1/32R-NSC02FC13SH
• Product Series: Rexroth Series 32, swash-plate variable displacement axial piston pump for closed circuits
• Geometric Displacement: 56 cm³/r
• Rated Continuous Working Pressure: 400 bar (high-pressure side port A/B)
• Peak Intermittent Working Pressure: 450 bar (≤10s per cycle, total ≤300h)
• Maximum Continuous Operating Speed: 3600 rpm
• Maximum Allowable Speed: 3900 rpm
• Theoretical Rated Flow: 201.6 L/min (@3600 rpm, at full displacement)
• Control Mode: EZ2 electric two-point variable control (solenoid driven swash plate bidirectional displacement)
• Integrated Charge Pump Displacement: 11.6 cm³/r, rated charge pressure 20 bar
• Integrated Valves: Bidirectional high-pressure relief valves + charge check valves + charge pressure relief valve
• Rotation Direction: Clockwise (viewed from drive shaft end), supporting bidirectional flow output
• Shaft Extension: Standard involute spline shaft
• Mounting Flange: SAE B 2-bolt standard flange, Series 32 mounting dimensions
• Through Drive: Supported for series mounting of same-size auxiliary pump at rear end
• Reference Weight: Approx. 38 kg
• Main Seal Material: FKM fluororubber
• Compatible Fluid: ISO VG32 / VG46 / VG68 high-quality anti-wear hydraulic oil
• Operating Oil Temperature Range: -25℃ to 90℃ (short-term maximum 115℃)
• Full series displacement and corresponding continuous speed:
  • A4VG40: 40 cm³/r, max continuous speed 4000 rpm
  • A4VG71: 71 cm³/r, max continuous speed 3300 rpm
  • A4VG90: 90 cm³/r, max continuous speed 3050 rpm
  • A4VG125: 125 cm³/r, max continuous speed 2850 rpm

Key Technical Advantages

1. EZ2 Electric Two-point Control with Fast Bidirectional Stepless Variable Response

   The solenoid-driven two-point variable mechanism switches control oil chamber pressure difference to drive the swash plate across neutral position, achieving stepless adjustment of flow direction and volume with commutation response time ≤120ms. The control logic is simple and reliable, adapting to forward/reverse and speed regulation demands of electronically controlled travel systems, and offering better electronic integration and remote control capability compared with hydraulic control.

2. 400bar High-pressure Grade Design for Excellent Heavy-duty Transmission Capacity

   The high-pressure side reaches 400 bar rated continuous pressure and 450 bar peak pressure, delivering high-torque hydrostatic transmission power. The cylinder block and valve plate adopt high-strength nodular cast iron and copper alloy friction pair matching, and the pistons are treated with alloy steel nitriding for uniform contact stress distribution. It withstands instantaneous pressure shocks during startup and commutation, adapting to harsh working conditions such as heavy-duty travel and winch transmission.

3. Integrated Closed Circuit Design for More Compact System Layout

   The pump integrates charge pump, bidirectional high-pressure relief valves, charge check valves and charge pressure relief valve internally, forming a complete closed hydraulic transmission circuit without a large number of external valves. The charge pump also supplies control oil for the variable mechanism, greatly simplifying system pipeline design, reducing installation space and leakage points, and improving overall reliability.

4. Micron-level Precision Machining with High Volumetric Efficiency and Low Leakage

   Core friction pairs including cylinder bore, valve plate and slipper are processed with CNC honing and super-finish grinding, with flatness controlled at micron level. Combined with optimized kidney-shaped valve port structure and slipper hydrostatic support design, it effectively reduces internal leakage on the high-pressure side, achieving volumetric efficiency above 94% under rated working conditions, lower heat loss in closed circuit, and excellent low-temperature starting performance.

5. Standardized Interface and Through-shaft Design for 100% Direct Interchangeability

   Mounting flange dimensions, shaft parameters, port positions and control interfaces fully match the drawing standards of original Rexroth Series 32 A4VG pumps, enabling direct replacement of original pumps of the same model. The rear end supports through-shaft drive for series mounting of auxiliary pumps or gear pumps of the same size, adapting to multi-circuit hydraulic system requirements, greatly shortening equipment downtime and reducing retrofitting costs.

Application Areas

• Construction machinery: Hydrostatic travel transmission systems for road rollers, pavers, milling machines and small roadheaders
• Agricultural machinery: Travel and operation hydraulic transmission for combine harvesters, high-horsepower tractors and self-propelled sprayers
• Industrial winch equipment: Closed hydraulic drive systems for mining winches, hoists and marine deck machinery
• Special vehicles: Hydraulic units for sanitation vehicles, airport ground support equipment and aerial work platforms
• Industrial hydraulic stations: Fixed equipment such as closed-circuit hydraulic test benches, machine tool spindle drives and injection molding machine clamping drives

Expert Maintenance Tips

1. Installation and Air Exhaust Specifications

   Ensure the coaxiality error between the pump shaft and prime mover output shaft is ≤0.1mm during installation, to avoid premature wear of shaft seal and bearing caused by excessive radial force. When filling oil for the first time in a closed circuit, oil must be injected into the circuit through the charge port, and air inside the pump and motor must be exhausted. Run the machine in jog mode for the first startup to confirm charge pressure is stable at 18~22 bar, to avoid dry friction damage to the valve pair caused by oil shortage.

2. Hydraulic Oil and Charge Pressure Requirements

   High-quality anti-wear hydraulic oil compliant with ISO VG46 is recommended, with oil cleanliness reaching NAS grade 8 or above, and high-pressure circuit filter accuracy no less than 10μm. Charge pressure shall be checked regularly; charge pressure shall not be lower than 15 bar during normal operation, as low pressure will cause slow response of the variable mechanism, cavitation and insufficient lubrication. Normal operating oil temperature should be controlled between 30℃ and 70℃; long-term operation above 90℃ will accelerate seal aging and oil deterioration.

3. Regular Maintenance Interval

   Check oil level and cleanliness every 500 working hours, inspect pipeline leakage and loose connections, and clean the return filter. Replace hydraulic oil and high-pressure filter every 2000 working hours, and clean tank bottom deposits at the same time. It is recommended to disassemble and inspect the wear condition of internal friction pairs, check charge pump gear clearance and variable spool flexibility every 4000 working hours to predict failure risks in advance.

4. Common Troubleshooting Key Points

   If system pressure is insufficient, first check whether the charge pump is worn and charge pressure is up to standard, then inspect whether the high-pressure relief valve setting is too low or the valve pair is worn. If commutation response is slow, focus on checking whether the solenoid valve is stuck or the control oil passage is blocked. If abnormal noise and overheating occur in the pump, check whether oil is aerated, oil viscosity is matched, and case drain is unobstructed. Do not operate the pump with oil shortage or insufficient charge pressure for a long time.