DBW20B2-5X/315 Rexroth Solenoid Relief Valve

Product Overview

The DBW20B2-5X/315-6EG24N9K4 is a Bosch Rexroth DBW series pilot-operated pressure relief valve with solenoid-controlled unloading. It combines a pilot-operated main relief valve with an attached directional spool valve, allowing the hydraulic system pressure to be limited while also providing electrically controlled unloading. The verified configuration has a 315 bar pressure rating, 350 bar maximum operating pressure, 500 L/min maximum flow and 24 VDC solenoid actuation.

The key engineering difference between DBW and a conventional DB pressure relief valve is the integrated directional valve. By actuating the directional spool valve electrically, the main pressure relief stage can be unloaded. This makes DBW particularly suitable for hydraulic power units and automated machinery where pump unloading must be coordinated with an electrical control system.

For replacement applications, the complete type code must be verified. The DBW20B2-5X/315-6EG24N9K4 configuration includes critical information regarding valve size, B-function, pressure stage, directional valve, voltage, manual override and electrical connector. The corresponding Bosch Rexroth material number is R900907684.

Our replacement manufacturing process can be engineered around the original mounting interface, hydraulic port configuration, pressure range and electrical control logic. Each replacement valve can be subjected to 100% simulated operating-condition testing covering pressure response, unloading operation, leakage and solenoid switching stability.

Technical Specifications

DBW20B2-5X/315-6EG24N9K4

• Manufacturer: Bosch Rexroth
• Series: DBW
• Complete model: DBW20B2-5X/315-6EG24N9K4
• Material number: R900907684
• Valve type: Pilot-operated pressure relief valve
• Construction: Pilot-operated relief stage with attached directional spool valve
• Nominal size: DBW20 / Size 20
• Component series: 5X
• Pressure rating: 315 bar
• Maximum operating pressure: 350 bar
• Maximum flow: 500 L/min
• Control principle: Hydraulic pilot control with solenoid-operated unloading
• Directional valve: 6E high-performance directional spool valve
• Solenoid voltage: 24 VDC
• Electrical connector: K4 according to EN 175301-803
• Manual override: N9 concealed manual override
• Pressure adjustment: Type 2, internal hexagon with protective cap
• Mounting: Subplate mounting
• Porting: ISO 6264-08-13
• Pilot oil configuration: Internal pilot supply and internal pilot return according to the specified version
• Seal material: NBR
• Compatible fluid classes: HL, HLP, HLPD, HVLP, HVLPD and selected HFC fluids
• Viscosity range: 10–800 mm²/s
• NBR fluid temperature range: −30 to +80 °C
• Maximum contamination level: ISO 4406 Class 20/18/15
• Approximate weight: 5.3 kg
• Displacement: Not applicable
• Rotational speed: Not applicable

DBW10B2-5X/100-6EG24N9K4

The second model included in the original title can be identified as:

• Complete model: DBW10B2-5X/100-6EG24N9K4
• Material number: R900906650
• Valve type: Pilot-operated pressure relief valve
• Nominal size: DBW10
• Component series: 5X
• Pressure rating: 100 bar
• Maximum operating pressure: 350 bar
• Maximum flow: 250 L/min
• Control: Pilot-operated pressure relief with solenoid unloading
• Solenoid voltage: 24 VDC
• Directional valve: 6E
• Electrical connector: K4
• Manual override: N9
• Seal material: NBR
• Mounting: Subplate mounting
• Porting: ISO 6264-06-09
• Approximate weight: 4.5 kg

Key Technical Advantages

1. Pilot-Operated Architecture for High Flow

The DBW design combines a pilot control stage with a main relief stage. For the DBW20 configuration, the maximum flow is 500 L/min, making it suitable for large industrial hydraulic circuits where a compact direct-acting valve would not provide the same flow-handling capability.

2. Integrated Solenoid Unloading

The attached 6E directional spool valve provides electrical unloading of the main relief stage. Combined with the G24 24 VDC solenoid, the valve can be integrated into PLC-controlled hydraulic power units and automatic machine sequences.

3. 315-Bar Pressure Class

The /315 code identifies the pressure setting class, while the documented maximum operating pressure is 350 bar. These two values should not be confused during commissioning or replacement selection.

4. Standardized Industrial Mounting

The DBW20 uses the ISO 6264-08-13 mounting interface, supporting installation on standardized hydraulic subplates and manifolds. This is particularly useful for industrial power-unit design and retrofit applications.

5. Switching Shock Damping Option

The DBW family can be configured with switching shock damping to reduce pressure peaks and decompression shock during directional-valve switching. This option is particularly relevant to high-flow, high-pressure circuits where rapid unloading could otherwise generate significant hydraulic transients.

6. Multiple Hydraulic Fluid Options

The standard documentation supports several hydraulic-fluid classes, including mineral oils and selected water-containing HFC fluids. Actual pressure, temperature and seal compatibility must be verified for the selected medium.

7. Engineering-Grade Model Identification

The full ordering code communicates the key functional configuration. In particular, the A/B electrical-failure behavior is operationally important: B versions establish the lowest adjustable circulation pressure in a power-loss or cable-break condition, while A versions maintain the pressure-limiting function.

Application Areas

Typical applications include:

• Large hydraulic presses
• Industrial hydraulic power units
• Metal-forming machinery
• Forging equipment
• Injection molding machinery
• Steel and metallurgical hydraulic systems
• High-flow clamping circuits
• Hydraulic test systems
• Large pump stations
• Automated pump unloading systems

The DBW10B2-5X/100-6EG24N9K4 is more appropriate for lower-flow industrial hydraulic circuits, including medium-sized power units, machine tools, clamping systems and compact hydraulic presses.

Expert Maintenance Tips

1. Verify the Electrical Failure Logic

Do not replace a DBW B version with an A version simply because the mounting interface and pressure rating appear similar. The A/B configuration changes the hydraulic response under power failure or cable break.

2. Check T- and Y-Port Back Pressure

Hydraulic counter pressure at the tank or pilot-return connections can add directly to the valve response pressure. For troubleshooting, unexpected high pressure should therefore be investigated together with T/Y back pressure.

3. Maintain Pilot-Circuit Cleanliness

The specified maximum hydraulic-fluid contamination level is ISO 4406 Class 20/18/15. Contamination of pilot passages can cause unstable pressure control, delayed switching or incomplete unloading.

4. Inspect the 24 VDC Solenoid Circuit

During maintenance, verify the 24 VDC supply, K4 connector wiring, protective earth and coil condition. The concealed N9 manual override should also be checked to ensure that it is not unintentionally influencing valve operation. Rexroth operating documentation requires the electrical supply to be disconnected and secured against restart before maintenance.

5. Evaluate Switching Shock at High Flow

With a maximum flow of 500 L/min, DBW20 systems can generate substantial transient forces during rapid unloading. Where large pumps or high-inertia hydraulic systems are involved, assess whether the switching-shock-damping option is required.

6. Verify the Complete Ordering Code

For a field replacement, confirm the complete sequence:

DBW + Size + A/B + Adjustment Type + Pressure Rating + Pilot Configuration + 6E/6SM + Voltage + Manual Override + Connector + Seal

This is essential because DBW10B2-5X/100 and DBW20B2-5X/315 differ significantly in flow capacity, mounting interface and valve size.

Engineering Replacement Assurance

For DBW20B2-5X/315-6EG24N9K4 and DBW10B2-5X/100-6EG24N9K4, engineering replacement should be based on the complete original configuration rather than the series name alone. Our replacement process can target in-place interchangeability, followed by 100% simulated operating-condition testing to verify pressure setting, unloading response, internal leakage, electrical actuation and functional stability before shipment.