4WREE6 Rexroth Proportional Directional Valve 16 L/min 315 Bar

Product Overview

The 4WREE6 series direct-operated proportional directional valve (model 4WREE6E16-23/G24K31A1V-655) is a high-performance electro-hydraulic proportional control component manufactured to original Bosch Rexroth technical standards. Featuring a direct-operated plate design with electrical position feedback and integrated on-board electronics (OBE), this valve enables continuous, precise proportional control of both direction and velocity of hydraulic actuators. With size 6 (NG6), rated flow of 16 L/min (at Δp = 10 bar), maximum operating pressure of 315 bar, it is engineered for demanding industrial and mobile hydraulic applications requiring high-accuracy flow control.

This product is dimensionally and functionally identical to the original Rexroth 4WREE6 series valve, with a mounting surface conforming to ISO 4401 (porting pattern per DIN 24 340 Form A). It offers true drop-in interchangeability, allowing direct replacement of same-specification OEM valves without modifying piping systems or control programs. Every unit undergoes 100% bench testing under simulated working conditions, including rated pressure holding, spool position accuracy, flow linearity, and internal leakage verification, ensuring performance consistency with the original equipment.

Technical Specifications

General Specifications

• Model: 4WREE6E16-23/G24K31A1V-655

• Product Series: 4WREE6 (Size 6 / NG6)

• Component Series: 2X

• Spool Type: E (4/3-way, closed center)

• Design: Direct-operated, plate mounting proportional directional valve

• Mounting Pattern: ISO 4401 / DIN 24 340 Form A / CETOP-RP 121 H

Hydraulic Parameters

• Rated Flow: 16 L/min (at Δp = 10 bar)

• Maximum Flow: 80 L/min (size 6)

• Maximum Operating Pressure (Ports P/A/B): 315 bar (4600 psi)

• Maximum Tank Port Pressure (Port T): refer to catalog curves

• Hydraulic Fluid: Mineral-based hydraulic oil (HLP / HLVP)

• Viscosity Range: 20 – 380 mm²/s (cSt)

• Fluid Temperature Range: -20°C to +80°C

• Filtration: ISO 4406 19/17/14 (NAS 1638 Class 10)

• Hysteresis: ≤ 0.05%

Electrical Parameters

• Supply Voltage: 24 VDC (G24)

• Voltage Tolerance: ± 10%

• Command Signal: 0 to ± 10 V (interface A1) / 4-20 mA (interface F1 optional)

• Solenoid Type: Proportional solenoid with central thread and detachable coil

• Integrated Electronics: OBE (On-Board Electronics)

• Maximum Coil Temperature: 150°C

• Protection Class: IP65 (with standard connector)

• Electrical Interface: K31 (ISO 4400 standard connector)

Materials & Construction

• Valve Body: High-strength cast iron

• Control Spool: Carburized steel, precision ground

• Seals: NBR / FKM (optional)

• Surface Treatment: Phosphating / anti-corrosion coating

Weight & Dimensions

• Weight: approx. 2.6 kg (size 6, dual solenoid version)

• Mounting Bolts: 4 × M5 (ISO 4762, grade 12.9)

• Recommended Tightening Torque: 8.9 Nm

Key Technical Advantages

1. Integrated OBE Electronics for Simplified System Architecture
The 4WREE6E16-23 integrates the proportional amplifier board directly into the valve body (On-Board Electronics), eliminating the need for an external amplifier. Users can directly drive the spool via a 0 to ±10 V voltage signal or 4-20 mA current signal. The integrated design reduces external wiring and cabinet space requirements while minimizing electromagnetic interference on signal transmission, enhancing system reliability. Electrical zero point can be adjusted via the Pg7 interface on the valve body for convenient maintenance.

2. Precision Spool Machining for High-Accuracy Flow Control
The clearance between spool and bore is controlled at micron level (approximately 0.0127 mm). Metering notches are precision-machined on the spool lands, allowing oil flow to begin before the lands fully clear the valve ports, delivering progressive flow characteristics. Combined with the electrical position feedback closed-loop control system, spool position accuracy is maintained with hysteresis ≤ 0.05%, enabling precise actuator speed control for high-accuracy synchronization applications.

3. Proportional Solenoid Actuation with Spring-Centered Return
Proportional solenoids with central thread and detachable coil are employed. The solenoid is mounted to the valve body via central thread, and the coil can be individually replaced without removing the entire valve. In the de-energized state, compression springs return the control spool to its mechanical center position (E-type spool provides closed-center function), ensuring a safe system state upon power loss. For spools with symbol “V”, the mechanical center position does not correspond to the hydraulic center position and requires closed-loop control to achieve hydraulic neutral.

4. 100% Simulated Working Condition Testing and Drop-in Interchangeability
Every 4WREE6E16-23/G24K31A1V-655 valve undergoes 100% bench testing prior to shipment, covering 315 bar rated pressure holding, spool position accuracy calibration, flow-signal linearity verification, internal leakage measurement, and solenoid response characterization. Mounting dimensions, port positions, electrical interfaces, and performance curves are strictly matched to the original Rexroth valve, enabling direct drop-in replacement without modifying piping or control programs.

Application Areas

• CNC Press Brakes: Ram synchronization control, pressure-position compound control

• Injection Molding Machines: Injection speed and holding pressure proportional control

• Hydraulic Presses: Proportional speed and direction regulation for pressing systems

• Metallurgical Equipment: Continuous casting machines, rolling mill auxiliary hydraulic control

• Hydro Power: Turbine governor systems, gate hoist hydraulic control

• Machine Tools: Hydraulic clamping systems, grinding machine feed control

• Testing Machines: Force-displacement closed-loop control for material testing

Expert Maintenance Tips

Installation Guidelines

1. Horizontal installation is recommended for the 4WREE6 series (coil facing upward or horizontal) to facilitate solenoid heat dissipation and proper oil immersion of the spool. Mounting surface flatness must be ≤ 0.05 mm. Use grade 12.9 M5 bolts and tighten diagonally in stages to 8.9 Nm.

2. Thoroughly flush all piping circuits before installation. Ensure no welding slag, metal chips, or particulate contaminants remain. Prior to first operation, circulate the system through a 10 μm filter element for a minimum of 30 minutes.

3. The PG fitting (11) must not be opened. Mechanical adjustment of the adjustment nut located below is prohibited and will damage the valve. Electrical zero point adjustment should be performed via the Pg7 interface using dedicated tools with the power supply disconnected.

Routine Maintenance Procedures

1. Fluid Cleanliness Management: Maintain system fluid cleanliness at ISO 4406 19/17/14 or better. Check fluid particulate contamination every 500 operating hours and replace filter elements and hydraulic fluid when contamination exceeds limits.

2. Electrical Connection Inspection: Periodically inspect the K31 connector for seal integrity and terminal tightness to maintain IP65 protection. Verify that the control signal cable shield is properly grounded to prevent spool oscillation caused by electromagnetic interference.

3. Coil Resistance Verification: Measure solenoid coil resistance every 1,000 operating hours. Deviation from factory value should not exceed ± 10%. The maximum allowable coil temperature is 150°C. If abnormal temperature rise is observed, check supply voltage and inspect for spool binding.

4. Internal Leakage Monitoring: Due to the design principle, the 4WREE series valves have inherent internal leakage that may increase over the service life. An annual internal leakage test is recommended. If leakage exceeds 150% of the factory standard, seal replacement should be scheduled.

5. Tank Line Back Pressure Management: The tank line must not be allowed to run empty. Under corresponding installation conditions, a preload valve (preload pressure approx. 2 bar) must be installed to maintain return line back pressure.