Rexroth A4VG180 & A4VG250 Plunger Pump Replacement | High-Displacement Closed Circuit Pump

The Rexroth A4VG Large-Displacement Series axial piston variable displacement pumps by Chengyuan Hydraulic—encompassing sizes A4VG125, A4VG140, A4VG175, A4VG180, and A4VG250, with highlight configurations including A4VG180HD3DM1/32R-NSD52F021D and A4VG250EP2D1/32R-NSD10F001DH—represent our flagship engineering lineup developed for high-power closed-circuit hydrostatic transmissions. These units offer 100% direct drop-in interchangeability with the original Bosch Rexroth Series 32 legacy units. All mechanical mounting parameters, shaft spline sizing, primary service line ports, and pilot control configurations match the OEM brand exactly, enabling a seamless field replacement without modifications to heavy-duty structural frames or high-pressure plumbing.

As the heavy-duty transmission module driving extreme-torque circuits, this series integrates main high-pressure relief valves, a high-capacity charge boost pump, and an adjustable pressure cut-off (D-valve). Recognizing that large-displacement pump failure leads to massive capital machine downtime, Chengyuan subjects every single unit to 100% rigorous full-load simulated working condition testing. This ensures peak volumetric performance, dynamic structural stability, and structural integrity under transient cross-center stress profiles. Outfitted with precision HD3 (hydraulic proportional with stroke limiters) or EP2 (24V DC electro-proportional) modules, these assemblies supply an ultra-reliable, cost-effective alternative to OEM components for global B2B procurement networks.

Technical Specifications

Model Code: A4VG180HD3DM1/32R-NSD52F021D (Hydraulic Pilot-Controlled Specification)

• Complete Model Code: A4VG180HD3DM1/32R-NSD52F021D

• Nominal Geometrical Displacement: 180.0 cc/rev ($cm^3/rev$)

• Nominal Operating Pressure: 400 bar (40 MPa)

• Maximum Peak Pressure: 450 bar (45 MPa)

• Maximum Rated Input Speed: 2500 rpm (at nominal working pressure & 1 bar absolute intake pressure)

• Maximum Delivery Flow Rate: Approx. 450 L/min at rated speed

• Control Mechanism: HD3 Control (Proportional control, hydraulic, pilot-pressure related, equipped with M1 mechanical stroke limiter)

• Overload Protection System: D (Integrated adjustable pressure cut-off valve to destroke pump safely during excessive stall loads)

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

• Sealing Configuration: N (Premium NBR nitrile seals paired with low-friction high-pressure shaft lips)

• Drive Shaft Type: S (Standard ANSI B92.1a splined shaft engineered for extreme torque inputs)

• Through-Drive Combination Interface: 52F021D (Rear auxiliary interface for tandem pump mounting; rear port configuration with metric fastening threads)

• Approximate Base Weight: 101.0 kg

Model Code: A4VG250EP2D1/32R-NSD10F001DH (Proportional Electro-Hydraulic Specification)

• Complete Model Code: A4VG250EP2D1/32R-NSD10F001DH

• Nominal Geometrical Displacement: 250.0 cc/rev ($cm^3/rev$)

• Nominal Operating Pressure: 400 bar (40 MPa)

• Maximum Peak Pressure: 450 bar (45 MPa)

• Maximum Rated Input Speed: 2400 rpm

• Maximum Delivery Flow Rate: Approx. 600 L/min

• Control Mechanism: EP2 Control (Electro-hydraulic proportional control with dual 24V DC proportional solenoids, centering spring-loaded with servo cylinder feedback)

• Overload Protection System: D (Integrated adjustable pressure cut-off override valve)

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

• Sealing Configuration: N (Heavy-duty high-longevity NBR sealing compound arrangement)

• Drive Shaft Type: S (Heavy-duty splined shaft optimized against torsional shear fracturing)

• Through-Drive Combination Interface: 10F001DH (Large-frame standard rear coupling flange for multi-stage tandem pump integration)

• Approximate Base Weight: 156.0 kg

Key Technical Advantages

• High-Rigidity Nodular Casting & Bimetallic Rotary Interfaces: Operating heavy frames (180cc/250cc) at 400 bar introduces massive structural stress and housing flex risks. Chengyuan utilizes an advanced nodular/compacted graphite iron monoblock housing. The core cylinder blocks are vacuum-sintered with high-specification bimetallic bronze layer coatings, assuring high bonding strength. This completely eliminates bronze peeling or seizure under severe over-center high-frequency reversals.

• Ultra-Low Hysteresis HD3 & EP2 Valving Execution: Heavy-duty applications require precise command execution. Our optimized HD3 hydraulic pilot loops and EP2 24V electric proportional valve blocks feature micron-grade mirror-lapped spool elements. By dramatically mitigating internal mechanical friction and sealing stiction, the system control hysteresis is restricted below 1.5%, delivering linear flow matching.

• Hydrostatically Balanced Cradle Swashplate Carriers: To manage the large tilting forces generated by oversized rotary kits, our swashplate cradles utilize hydrostatically balanced fluid-film bearing paths. High-pressure micro-channel pathways generate a continuous static oil film, preventing direct metal-to-metal contact during intense high-pressure cycling and doubling structural lifespan relative to typical aftermarket builds.

• 100% Load-Cycle End-Of-Line Simulation Testing: Unlike superficial zero-load or low-pressure spinning routines common in the aftermarket sector, Chengyuan mandates a comprehensive test protocol for the A4VG180 and A4VG250. Every pump must execute full-load cycles up to 400 bar under continuous, dynamic load pulses. We map pressure cut-off (D-valve) response timing, high-temperature case drain flow metrics, and boost pressure curves to guarantee field-readiness out of the box.

Application Areas

These high-displacement plunger pumps are purpose-built to actuate massive closed-circuit hydrostatic systems:

• Heavy Construction & Infrastructure: Heavy-tonnage concrete boom pump trucks (primary closed-loop circuit driving the concrete cylinders for Putzmeister, Schwing, Zoomlion, and Sany fleets), large-frame rotary drilling rigs (rotary head and primary winch drives).

• Mining & Underground Substructure: Tunnel Boring Machine (TBM) cutterhead drive hydraulic stations, ultra-high capacity industrial shredders, heavy scrap metal shears, and underground LHD mining transport loaders.

• Marine & Offshore Systems: Deep-sea mooring winch systems, heavy deck cargo cranes, and hydrostatic steering and thruster-propulsion loops on engineering vessel fleets.

Expert Maintenance Tips

• Large Case Volume Pre-Filling & Manual Bleeding: The housing of an A4VG180 or A4VG250 pump retains a massive amount of fluid. Prior to starting the prime mover, you must fill the pump case completely through the highest drain port (L1 or L2) using a micro-filtered fluid ($\le 5\mu m$). Manually rotate the input shaft 3 to 5 revolutions by hand to evacuate trapped air bubbles within the piston bores and the swashplate servo cylinders; failing to do so will prompt catastrophic slipper face scoring from initial dry friction.

• Charge Boost Pressure & Dynamics Verification: Given the high fluid volume exchanged across the circuit during displacement changes, real-time pressure monitoring at test port G is crucial. The charge pressure must register firmly between 20 and 24 bar when the pump is in neutral, and it must never fall below 16 bar during extreme peak over-center load cycles. If a severe pressure drop occurs, inspect the boost inlet filter element immediately.

• Case Drain Thermal Profiles & Loop Cleanliness: Because closed transmission systems shed thermal loads via case drainage, verify that the continuous case drain oil temperature remains below 90°C (and never exceeds 115°C at localized bearing races). Maintain absolute fluid hygiene to meet ISO 4406 18/15/12 parameters; under 250cc structural compression forces, small micro-particles behave like cutting tools, causing catastrophic scoring across the bimetallic interfaces.