Rexroth A4VG Series Control Valve | A4VG28 A4VG90 A4VG175 | Electric & Hydraulic Control

Chengyuan Hydraulic produces the A4VG Series Control Valve Modules, precision control components specifically developed for Rexroth axial piston variable pumps. This range covers the requirements for pump sizes from A4VG28 to A4VG250. As the heart of speed and direction control in closed-circuit systems, our valves support Electric Proportional Control (EP), Hydraulic Pilot Control (HD), and Manual Servo Control (HW). Every control valve undergoes 100% simulated condition testing before leaving the factory to strictly verify the linear relationship between pilot pressure and swashplate angle, ensuring dynamic response and precision matching OEM standards for 100% original-place interchangeability.

Technical Specifications :

• Compatible Pump Models: A4VG28, A4VG40, A4VG56, A4VG71, A4VG90, A4VG125, A4VG175, A4VG250

• Control Types: EP (Electric Proportional), HD (Hydraulic Pilot), HW (Manual Servo), DA (Speed Related)

• Solenoid Voltage: 12V DC / 24V DC

• Control Current Range: 200 mA – 1200 mA (specification dependent)

• Pilot Pressure Range: 4 bar – 25 bar (linear adjustment zone)

• Operating Fluid: Mineral-based hydraulic oil (DIN 51524)

• Media Temperature: -25°C to +90°C

• Protection Class: IP67 / IP69K (solenoid portion)

Key Technical Advantages:

• High-Precision Spool Matching: The internal spool sets are crafted from high-grade alloy steel with vacuum quenching and micron-level grinding. This ensures minimal hysteresis and microsecond-level response to pump displacement commands.

• Optimized Hysteresis Characteristics: Equipped with high-performance wet-pin proportional solenoids, the electromagnetic hysteresis loop is optimized. This guarantees consistent flow output during current ramps, significantly enhancing operator comfort.

• High-Pressure Integrated Design: The valve body is monoblock-cast from high-strength ductile iron, capable of sustaining frequent pressure spikes in closed circuits without deformation, preventing control failure due to body fatigue.

• Full-Condition Compatibility Testing: All units are subject to 100% simulated load aging tests under extreme vibrations and temperature ranges, ensuring stable pilot pressure output in both arctic cold and tropical heat.

Application Areas:

• Road Machinery: Travel drive systems for pavers, rollers, and cold planers.

• Excavation Machinery: Closed-circuit travel drives for wheeled excavators.

• Agricultural Machinery: Transmission control for combine harvesters and self-propelled sprayers.

Expert Maintenance Tips:

• Signal Monitoring: After replacing an EP valve, use a controller to monitor the current. If fluctuations occur, check the wiring harness shielding to prevent EMI-induced displacement erraticism.

• Pilot Fluid Cleanliness: A4VG control valves are highly sensitive to contamination. Ensure a 10μm fine filter is installed to prevent micro-particles from jamming the pilot spool, which causes “speed loss.”

• Zero-Point Calibration: After installation, perform a zero-point adjustment under no-load conditions. Ensure the pump swashplate returns to dead center when the solenoid is de-energized to prevent dangerous “creeping.”