Product Overview
The 3DREPE6A-21/45EG24K31/A1M is a Bosch Rexroth 3DREPE series direct-operated proportional pressure reducing valve in 3-way design, NG6 (CETOP 3) size, with mounting pattern conforming to ISO 4401-03 . This 3-way proportional pressure reducing valve features Type A spool symbol with direct-operated construction, actuated by proportional solenoids featuring central thread and detachable coil.
The 3DREPE series features integrated on-board electronics (OBE) , eliminating the need for external amplifiers. The valve enables precise control of pressure and flow direction via electrical signals, with a spring-centered control spool that automatically returns to neutral when de-energized.
Model Code Breakdown (3DREPE6A-21/45EG24K31/A1M):
3DREP: 3-way proportional pressure reducing valve
E: With integrated control electronics (OBE)
6: Nominal Size NG6 (6 mm)
A: Spool Symbol — Type A
21: Design Series (20–29, unchanged installation and connection dimensions)
45: Pressure stage — 45 bar
E: With wet-type solenoid
G24: DC 24V supply (G = DC)
K31: Control electronics interface configuration
A1M: Seal material and option code (M = NBR seals)
Technical Specifications
Model: 3DREPE6A-21/45EG24K31/A1M
Brand: BOSCH REXROTH
Series: 3DREPE Series, 2X Component Series
Product Type: Direct Operated Proportional Pressure Reducing Valve, 3-Way Version
Spool Symbol: Type A
Nominal Size: NG6 (6 mm)
Mounting Standard: ISO 4401-03 / DIN 24340 Form A
Mounting Type: Subplate Mounting
Maximum Operating Pressure: 100 bar (1450 PSI)
Maximum Flow Rate: 15 L/min (3.96 GPM)
Pressure Stage: 45 bar
Supply Voltage: 24V DC
Control Electronics: Integrated (OBE)
Command Value Input: ±10V (A1 interface)
Electrical Connector: Device plug per DIN EN 175301-804
Seal Material: NBR
Hydraulic Fluids: Mineral oil (HL, HLP) per DIN 51524
Solenoid Type: Wet-Pin DC Solenoid
Control Spool: Spring Centered
Weight: Approx. 2.7 kg
Key Technical Advantages
1. Integrated On-Board Electronics (OBE) — No External Amplifier Required
The 3DREPE6A-21/45EG24K31/A1M comes standard with integrated on-board electronics (OBE) , directly accepting ±10V command signals. Compared to the 3DREP type requiring external amplifiers, the OBE design significantly simplifies the electrical control architecture, reduces external component count, and minimizes system failure points.
2. Direct-Operated 3-Way Proportional Pressure Reducing Function
Features direct-operated proportional solenoids directly actuating the control spool. The spool is spring-centered, automatically returning to neutral when de-energized, with ports A and B connected to T for unrestricted oil return to tank. By energizing the proportional solenoid, the control spool shifts to open connections from P to B and A to T, achieving precise proportional pressure control.
3. Wet-Pin DC Solenoid for Quiet, Long-Life Operation
Features wet-pin DC solenoids with central thread and detachable coil. The movable iron core operates fully submerged in hydraulic oil, providing lubrication to reduce wear and cushioning against switching impact and vibration — ensuring extended service life and extremely low noise levels.
4. Two Spool Position Options for Flexible Adaptation
The 3DREP/3DREPE series offers 2 spool position (A or B type) configurations. Type A is equipped with solenoid “a” only, while Type B is equipped with solenoid “b” only, with the second proportional solenoid position replaced by a plug screw. Type A is suitable for single-direction pressure control applications.
5. International Standard Compliance for High Installation Compatibility
Mounting conforms to ISO 4401-03, DIN 24340 Form A, and CETOP-RP 121H international standards. Fully compatible with globally adopted NG6 interfaces for direct replacement of same-series, same-specification products. Subplates can be ordered separately per Rexroth catalog sheet RD 45052.
6. Optional Manual Override and ATEX Explosion-Proof Version
Optional manual override is available for emergency operation during power failure. An ATEX explosion-proof version (3DREP 6 ../..XE) is also available for potentially explosive atmospheres.
Application Areas
Injection Molding Machinery — Precise proportional control of injection and holding pressure
Die-Casting Machines — Proportional regulation of injection pressure
CNC Machine Tools — Precise pressure control for hydraulic clamping and unclamping
Material Testing Machines — Precise proportional control of loading force
General Industrial Hydraulic Systems — Various applications requiring precise proportional pressure control
Potentially Explosive Atmospheres — Optional ATEX explosion-proof version available
Expert Maintenance Tips
1. Installation Guidelines
Mounting surface must conform to ISO 4401-03 / DIN 24340 Form A 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.
2. Hydraulic Fluid Cleanliness
Compatible fluids: Mineral oil (HL, HLP) per DIN 51524.
Seal material: NBR . For phosphate ester and other specialty fluids, select FKM seal option (V code).
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
3DREPE6A-21/45EG24K31/A1M uses 24V DC supply.
Command value input: ±10V (A1 interface) .
Electrical connector per DIN EN 175301-804 standard. Ensure the connector is fully locked during installation.
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. Manual Override
Optional manual override is available.
Manual operation is for emergency use only and is not recommended for continuous duty.
Note: Unintentional activation of the manual override may cause uncontrolled machine movement.
6. 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.
