Product Overview
The 4WREE6V08-2X/G24K31/A1V (Material Number R900909367) is a Bosch Rexroth 4WREE series direct-operated proportional directional valve, NG6 (CETOP 3) size, with mounting pattern conforming to ISO 4401-03-02-0-05. This 4/3-way proportional directional valve features Symbol V spool, direct-operated construction with proportional solenoids featuring central thread and detachable coil.
The 4WREE series is a direct-operated proportional directional valve with electrical position feedback and integrated electronics (OBE) . The solenoids are controlled by the integrated electronics, enabling precise control of flow direction and size via electrical signals. Internal piston position feedback ensures extremely high control accuracy.
Model Code Breakdown (4WREE6V08-2X/G24K31/A1V):
4WREE: Direct-operated proportional directional valve with electrical position feedback and integrated electronics (OBE)
6: Nominal Size NG6 (6 mm)
V: Spool Symbol V
08: Nominal flow rating (8 L/min @ Δp = 10 bar per control edge)
2X: 2X Component Series (20–29, unchanged installation and connection dimensions)
G24: DC 24V supply (G = DC)
K31: Control electronics interface configuration — Analog, command value ±10V
A1V: Seal material and option code (FKM seals)
Technical Specifications
Model: 4WREE6V08-2X/G24K31/A1V
Material Number: R900909367
Brand: BOSCH REXROTH
Series: 4WREE Series, 2X Component Series
Product Type: Direct-operated proportional directional valve with electrical position feedback and integrated electronics (OBE)
Spool Configuration: 4/3-way
Spool Symbol: Symbol V
Nominal Size: NG6 (6 mm)
Mounting Standard: ISO 4401-03-02-0-05 / CETOP 3
Mounting Type: Subplate Mounting
Number of Ports: 4 main ports
Switching Positions: 3 positions
Maximum Operating Pressure: 350 bar (5075 psi)
Nominal Flow (@ Δp = 10 bar): 8 L/min
Maximum Flow: 58–80 L/min
Supply Voltage: 24V DC
Command Value Input: Analog, ±10V
Electrical Connector: 7-pin device plug (6 + PE) per EN 175201-804
Protection Class: IP65 (with properly installed connector)
Seal Material: FKM (Fluoroelastomer)
Hydraulic Fluids: HL, HLP, HLPD, HVLP, HVLPD, HETG, HEES, HEPG, HFDU, HFDR
Weight: 2.44 kg
Key Technical Advantages
1. Integrated On-Board Electronics (OBE) — No External Amplifier Required
The 4WREE6V08-2X/G24K31/A1V comes standard with integrated on-board electronics (OBE) , directly accepting ±10V command signals. This significantly simplifies the electrical control architecture of hydraulic systems, reduces external component count, minimizes system failure points, and reduces wiring complexity.
2. Electrical Position Feedback for Extremely High Control Accuracy
The 4WREE series is equipped with electrical position feedback, enabling precise monitoring and control of spool position via internal piston position feedback. The feedback signal is compared with the command value, continuously correcting spool position to ensure extremely high repeatability and minimal hysteresis.
3. Direct-Operated Design for Fast Response
The direct-operated design employs proportional solenoids to directly actuate the control spool with no pilot stage delay. Solenoids feature central thread and detachable coil construction for easy maintenance.
4. FKM Seals for Broad Fluid Compatibility
Equipped with FKM (fluoroelastomer) seals, compatible with HL, HLP, HLPD, HVLP, HVLPD, HETG, HEES, HEPG, HFDU, HFDR, and other hydraulic fluids. FKM seals offer superior heat and chemical resistance for phosphate esters and other specialty fluids.
5. Symbol V Spool — Adapts to Specific Hydraulic Circuit Requirements
Features Symbol V spool, which has specific hydraulic characteristics in the neutral position. When the electric valve control loop is closed, the spool is positioned in the hydraulic neutral position. Symbol V adapts to specific hydraulic circuit design requirements, covering a wide range of applications alongside other symbols such as E and W.
6. International Standard Compliance for High Installation Compatibility
4WREE series mounting conforms to ISO 4401-03-02-0-05 / CETOP 3 international standards. Fully compatible with globally adopted NG6 interfaces for direct replacement of same-series, same-specification products. The 7-pin device plug (6 + PE) conforms to EN 175201-804.
Application Areas
Injection Molding Machinery — Precise proportional control of injection speed and holding pressure
Die-Casting Machines — Proportional regulation of injection speed and pressure
CNC Machine Tools — Proportional control of spindle feed rates and worktable indexing
Material Testing Machines — Precise proportional control of loading force and displacement
Metallurgical Equipment — Precise position and speed control for rolling mill hydraulic systems
Wind Turbine Systems — Hydraulic proportional control for pitch systems
General Industrial Hydraulic Systems — Various high-precision applications requiring proportional directional and flow control
Expert Maintenance Tips
1. Installation Guidelines
Mounting surface must conform to ISO 4401-03-02-0-05 / CETOP 3 standards.
Thoroughly clean the mounting surface and all ports (P, A, B, T) before installation to prevent foreign particles from entering and causing spool sticking or seal damage.
Tighten mounting bolts evenly to the specified torque to ensure proper O-ring sealing between the valve body and mounting surface.
Important Notice: The PG fitting (11) must not be opened. Mechanical adjustment of the adjustment nut located below is prohibited and damages the valve!
2. Hydraulic Fluid Cleanliness
Recommended fluids: Mineral oils per DIN 51524 (HL, HLP, HLPD, HVLP, HVLPD) or synthetic oils (HETG, HEES, HEPG, HFDU, HFDR).
Recommended fluid cleanliness: ISO 4406 18/16/13 or better.
Install a return line filter with minimum 10 μm filtration rating.
3. Electrical Connection Specifications
4WREE6V08-2X/G24K31/A1V uses 24V DC supply. Verify supply voltage matches coil rated voltage before connection.
Command value input: ±10V.
Electrical connector: 7-pin device plug (6 + PE) per EN 175201-804. Ensure the connector is fully locked to prevent contact issues caused by vibration.
Shielded cables are recommended for command signal connections to prevent electromagnetic interference affecting control precision.
4. Tank Line Precautions
The tank line must not be allowed to run empty.
With corresponding installation conditions, a preload valve (preload pressure approx. 2 bar) must be installed.
5. Periodic Maintenance Inspection
Inspect the valve body for external oil leakage every 2,000 operating hours or at least annually.
Check electrical connectors for looseness, oxidation, or moisture ingress.
Periodically inspect OBE electronics status to confirm normal power supply and command signal.
If response lag or reduced control precision is observed, first check system fluid cleanliness and verify the spool is not sticking.
Solenoid coils can be replaced without disturbing hydraulic connections.
Note: Due to the design principle, internal leakage which may increase over the life cycle is inherent to the valves.
