A10VSO71DR/31R-VPA12N00 | Rexroth Axial Piston Pump Replacement

The A10VSO71DR/31R-VPA12N00 axial piston pump engineered by Chengyuan Hydraulic is a premium, heavy-duty hydraulic power solution designed for 100% direct interchangeability with the original Bosch Rexroth 31 series. Manufactured to strict global engineering standards, this variable displacement pump matches the exact mounting dimensions, port configurations, and performance curves of the OEM brand, enabling seamless drop-in replacement with zero modification to your existing hydraulic circuits.

Built for open-circuit hydraulic systems, this model features a swashplate design integrated with a highly responsive DR (Constant Pressure) control valve. To ensure uncompromising reliability, every single A10VSO 71 pump manufactured by Chengyuan undergoes rigorous 100% simulated working condition testing prior to shipment. This guarantees peak volumetric efficiency, minimum energy dissipation, and maximum uptime under the most demanding industrial and mobile applications.

Technical Specifications

• Complete Model Code: A10VSO71DR/31R-VPA12N00

• Base Series: A10VSO Series 31

• Nominal Displacement: 71.0 cc/rev ($cm^3/rev$)

• Nominal Pressure: 280 bar (28 MPa)

• Maximum Peak Pressure: 350 bar (35 MPa)

• Maximum Speed (at 1 bar absolute pressure): 2100 rpm

• Maximum Flow Rate: Approx. 149 L/min (at 2100 rpm)

• Control Device: DR Control (Pressure Control, adjustment range: 50 – 280 bar)

• Direction of Rotation: R (Clockwise, viewed from shaft end)

• Seals: V (FKM / Viton seals, high-temperature and synthetic fluid resistant)

• Shaft End: P (Parallel straight shaft with key, DIN 6885)

• Mounting Flange: A (SAE 2-hole standard)

• Service Line Ports: 12N00 (SAE flange ports, rear connections, metric fastening threads)

• Approximate Weight: 33.0 kg

Key Technical Advantages

• High Volumetric Efficiency: Utilizing premium bi-metal cylinder blocks and precision-ground pistons with advanced hardening treatments, the internal clearances are minimized. This limits internal leakage, maintaining over 95% volumetric efficiency even when operating continuously at its 280 bar rated pressure.

• Millisecond DR Control Response: The integrated DR pressure compensator valve is finely calibrated for dynamic sensitivity. Once the system reaches the preset pressure threshold, the swashplate destokes to zero flow in milliseconds, switching the system to an energy-saving standby mode and drastically reducing oil heat generation.

• Fluid Dynamic Noise Reduction: Featuring optimized internal flow passages and a custom-engineered pre-compression chamber design on the valve plate, fluid pulsation and pressure shocks are heavily suppressed. This results in an operational noise level 3 to 5 dB(A) lower than generic aftermarket pumps.

• Superior Fluid & Thermal Resistance: Equipped with genuine FKM (Viton) seals as standard, the pump easily withstands high thermal conditions and exhibits excellent chemical compatibility with mineral oils and fire-resistant fluids (e.g., polyol esters), preventing shaft seal weepage.

Application Areas

This high-pressure piston pump is widely deployed across sectors requiring precise pressure regulation and high duty cycles:

• Industrial Machinery: Plastic injection molding machines, die-casting machinery, hydraulic balers, heavy-duty scrap shears, and machine tool hydraulic power units (HPUs).

• Mobile & Construction Equipment: Rotary drilling rigs, concrete transit mixer auxiliary drives, and small mobile crane winch systems.

• Metallurgy & Mining: Blast furnace hydraulic stations in steel mills and heavy conveyor hydraulic drives.

Expert Maintenance Tips

• Mandatory Initial Case Filling: Before initial startup or restarting after a prolonged shutdown, the pump housing must be filled with clean hydraulic oil via the highest drain port (Port L or L1). Operating the pump dry will cause immediate, catastrophic scoring on the piston shoes and swashplate.

• Fluid Cleanliness Standards: The long-term reliability of the A10VSO series relies heavily on fluid hygiene. System oil must be strictly maintained at or cleaner than ISO 4406 20/18/15 (NAS Class 9). We recommend using high-pressure or return filters with a filtration rating of $\le 10 \mu m$.

• Case Drain Line Pressure: The case drain line must be piped directly back to the reservoir without restrictions and terminate below the minimum oil level. Ensure that the internal case pressure never exceeds 0.5 bar, as excessive backpressure will compromise the shaft lip seal.