DBDH6K1X/400 DBDS6K1X/200 DBDA10K1X/315 Rexroth Relief Valve 630 bar

Product Overview

The DBD/DB/DBW series pressure relief valves are direct-operated seat valves (DBD/DBDS/DBDH/DBDA) and pilot-operated pressure relief valves (DB/DBW) engineered by Bosch Rexroth for industrial hydraulic systems, widely used for system pressure limitation and overload protection. The direct-operated series utilizes poppet or ball seat designs to balance system pressure directly against spring force; the pilot-operated series (DB/DBW) uses a pilot stage to control the main spool for precise large-flow pressure control and solenoid unloading.

This range covers the following models:

Direct-Operated Relief Valves (DBD Series) :

• DBDH6K1X/400 (R900424202 / R900476862): NG6 screw-in cartridge, max pressure 400 bar, flow 50 L/min

• DBDH10P10B/315: NG10 subplate mounting, adjustable pressure range 0–31.5 bar

• DBDS6K1X/200 (R900423724): NG6 screw-in cartridge, max pressure 315 bar, flow 200 L/min

• DBDA10K1X/315 (R900425164): NG10 screw-in cartridge, max pressure 315 bar, flow 10 L/min

Pilot-Operated Relief Valves (DB/DBW Series) :

• DB10 / DBW10: NG10 pilot-operated relief valve, max pressure 350 bar, max flow 650 L/min

⚠️ Series Notes:

• DBD = Direct-Operated Seat Valve

• DBDS = Direct-Operated Seat Valve with damping piston (25–400 bar poppet design)

• DBDH = Direct-Operated Seat Valve, high-pressure (630 bar ball seat, NG10 only)

• DBDA = Direct-Operated Seat Valve, specific pressure rating configuration

• DB = Pilot-Operated Pressure Relief Valve

• DBW = Pilot-Operated Pressure Relief Valve with solenoid unloading

• NG6 / NG10 = Nominal size 6 / 10

Our complete range of Rexroth pressure valves strictly adheres to OEM technical standards, achieving 100% direct interchangeability with original components. Every unit undergoes 100% simulated operating condition bench testing prior to shipment, ensuring performance parameters are fully consistent with genuine Rexroth products. Direct replacement significantly reduces equipment downtime and maintenance costs.

Technical Specifications

DBDH6K1X/400 (R900424202 / R900476862)

• Product Series: Bosch Rexroth DBDH series direct-operated seat valve

• Model Code: DBDH6K1X/400

• Material Number (MPN) : R900424202 / R900476862

• Brand: Rexroth

• Product Type: Direct-operated pressure relief valve

• Nominal Size: NG6 (Size 6)

• Component Series: 1X

• Mounting Type: Screw-in cartridge

• Cavity: M28×1.5

• Maximum Operating Pressure: 400 bar (5800 psi)

• Maximum Flow: 50 L/min (13 gpm)

• Poppet Type: Poppet with damping piston (25–400 bar)

• Seal Material: FKM / NBR

• Compatible Fluids: HL, HLP, HLPD, HVLP, HVLPD, HETG, HEES, HFDU, HFDR

• Ports: G1/4

• Adjustment Types: Hexagon with protective cap / Rotary knob / Hand wheel / Lockable rotary knob

• Weight: Approx. 0.414 kg

DBDH10P10B/315

• Product Series: Bosch Rexroth DBDH series direct-operated seat valve

• Model Code: DBDH10P10B/315

• Brand: Rexroth

• Product Type: Direct-operated pressure relief valve

• Nominal Size: NG10 (Size 10)

• Mounting Type: Subplate mounting

• Pressure Rating Code: 10 (adjustable range 0–31.5 bar)

• Maximum Pressure: 315 bar

• Maximum Flow: Approx. 120 L/min (@ 10 bar pressure drop)

• Poppet Type: Poppet with damping piston (25–400 bar)

• Adjustment Type: Adjustment screw with protective cap

• Seal Material: FKM (V-type seal)

• Compatible Fluids: Mineral oil (HL, HLP), phosphate ester (HFD-R)

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

• Viscosity Range: 10–800 mm²/s

• Weight: Approx. 3.7 kg

DBDS6K1X/200 (R900423724)

• Product Series: Bosch Rexroth DBDS series direct-operated seat valve

• Model Code: DBDS6K1X/200

• Material Number (MPN) : R900423724

• Brand: Rexroth

• Product Type: Direct-operated pressure relief valve

• Nominal Size: NG6 (Size 6)

• Component Series: 1X

• Mounting Type: Screw-in cartridge

• Maximum Operating Pressure: 315 bar (4568 psi)

• Maximum Flow: 200 L/min (52.8 gpm)

• Poppet Type: Poppet with damping piston (25–315 bar)

• Seal Material: NBR

• Compatible Fluids: HL, HLP, HLPD, HVLP, HVLPD, HFC

• Ports: G1/4

• Adjustment Type: Hexagon with protective cap

• Weight: Approx. 0.4 kg

DBDA10K1X/315 (R900425164)

• Product Series: Bosch Rexroth DBDA series direct-operated seat valve

• Model Code: DBDA10K1X/315

• Material Number (MPN) : R900425164

• Brand: Rexroth

• Product Type: Direct-operated pressure relief valve

• Nominal Size: NG10 (Size 10)

• Component Series: 1X

• Mounting Type: Screw-in cartridge

• Maximum Operating Pressure: 315 bar (4569 psi)

• Maximum Flow: 10 L/min (2.64 gpm)

• Poppet Type: Poppet with damping piston

• Seal Material: NBR

• Compatible Fluids: HL, HLP, HLPD, HVLP, HVLPD, HFC

• Adjustment Type: Lockable rotary knob

• Weight: Approx. 0.659 kg

DB/DBW Series (Pilot-Operated Relief Valves, General Specifications)

• Product Series: Bosch Rexroth DB / DBW series pilot-operated relief valve

• Product Type: Pilot-operated relief valve / Pilot-operated relief valve with solenoid unloading

• Nominal Size: NG10 to NG32

• Component Series: 5X

• Maximum Operating Pressure: 350 bar

• Maximum Flow: 650 L/min

• Mounting Type: Subplate mounting

• Adjustment Types: Multiple options available

Key Technical Advantages

1. Direct-Operated Design for Extremely Fast Response (DBD/DBDS/DBDH/DBDA Series)

The DBD series features a direct-operated seat valve design where system pressure acts directly on the poppet or ball surface, overcoming spring force to initiate relief. Compared to pilot-operated relief valves, the direct-operated design delivers significantly faster response—opening for relief instantaneously upon pressure overshoot to provide the fastest possible overload protection. Additionally, the direct-operated design does not rely on pilot oil circuits, maintaining reliable opening characteristics even during severe system pressure fluctuations.

2. Ultra-High Pressure Rating – 630 bar Industry Benchmark

The DBDH series supports maximum operating pressures up to 630 bar (ball seat design, NG10 only). DBDH6K1X/400 supports 400 bar operating pressure. This pressure rating positions Rexroth direct-operated relief valves among the highest-rated relief valves available, making them particularly suitable for ultra-high-pressure hydraulic systems, heavy machinery, and extreme-duty applications.

3. Ball/Poppet Seat Design – Essentially Zero Leakage

The ball or cone poppet hard-sealing design delivers extremely low internal leakage (essentially zero leakage) in the closed position. DBDH series supports high-pressure ball seat designs up to 630 bar; DBDS series features poppet with damping piston designs for 25–400 bar ratings. The ball/poppet configuration maintains excellent sealing performance even after extended service, making it particularly suitable for applications requiring long-term pressure holding.

4. Pilot-Operated Large-Flow Control (DB/DBW Series)

The DB/DBW series features pilot-operated construction suitable for high-flow applications (NG10 up to 650 L/min). The DBW series integrates a solenoid directional valve on the DB series base, enabling solenoid-actuated system unloading at any time. Via port X, the valve can be unloaded or switched to a secondary pressure setting, providing significant flexibility for multi-stage pressure control applications.

5. Multiple Mounting Options and Flexible Configurations

Rexroth pressure valves offer screw-in cartridge (K type) and subplate mounting (P type) options. Screw-in cartridge valves can be installed directly into manifold blocks, saving valuable installation space; subplate types conform to standard mounting interfaces. Adjustment options include hexagon with protective cap, rotary knob, hand wheel, and lockable rotary knob.

6. 100% Direct Interchangeability and Simulated Condition Testing

All models strictly adhere to Rexroth original mounting dimensions and interface standards (ISO 4401 / DIN 24340). Cartridge valves of the same size and mounting type are physically and functionally interchangeable across brands, enabling 100% direct interchangeability without manifold modification or system adjustment. Every unit undergoes 100% simulated operating condition bench testing prior to shipment, ensuring consistent, stable performance at rated pressure and flow.

Application Areas

• Ultra-High-Pressure Hydraulic Systems: Overload protection for presses and hydraulic tools

• Heavy Construction Machinery: Pressure limitation for excavators, large wheel loaders, mining equipment

• Accumulator Circuits: Long-term pressure holding with essentially zero leakage

• Hydraulic Clamping Systems: Clamping force protection for machine tools and workholding fixtures

• Machine Tool Hydraulic Systems: Pump port safety relief valves for maximum pressure limitation

• DB/DBW Series: Applications requiring high-flow (650 L/min) or solenoid unloading capabilities

• Test Equipment: Pressure limitation and safety protection for hydraulic test benches

Expert Maintenance Tips

1. Verify Model and System Compatibility Prior to Installation

Rexroth pressure valves offer multiple sizes (NG6/NG10), mounting types (K type screw-in cartridge / P type subplate), and pressure ratings (25–630 bar). Confirm prior to installation:

• Size meets system flow requirements (DBDH6=50 L/min, DBDS6=200 L/min, DBDA10=10 L/min)

• Mounting type matches the manifold (K type screw-in cartridge / P type subplate)

• Pressure rating covers system operating pressure

2. Screw-in Cartridge (K Type) Installation Precautions

For screw-in cartridge types (DBDH6K1X/400, DBDS6K1X/200, DBDA10K1X/315), ensure the cavity is clean, free of burrs, and free of metal debris prior to installation. Use proper tools for installation and torque to the values specified in Rexroth technical manuals. Never use impact or hammering methods during installation, as this may damage internal poppet components or springs.

3. Subplate Mounting (P Type) Precautions

DBDH10P10B/315 features subplate mounting. Ensure the mounting surface is clean, scratch-free, and meets flatness specifications prior to installation. Use a torque wrench to tighten mounting bolts diagonally in sequence.

4. Pressure Setting and Commissioning

DBD series relief valves have adjuster screw seals exposed to system pressure—system pressure must be relieved before making adjustments. Correct procedure: check current setting → relieve system pressure → adjust valve → re-pressurize and verify new setting. System pressure can be set steplessly via the adjustment element. During commissioning, start from low pressure and gradually increase to the set value.

5. Back Pressure Effects

Back pressure at the tank port of DBD series relief valves directly adds to the valve setting at a 1:1 ratio. Ensure tank line back pressure is as low as possible, or account for it during setting.

6. System Cleanliness Management

Rexroth direct-operated relief valves feature tight poppet clearances and demand adequate oil cleanliness. Recommended system cleanliness: NAS 1638 Class 9 or ISO 4406 20/18/15. Thoroughly flush system piping prior to installation.

7. Periodic Functional Checks

Perform functional checks every 2,000 operating hours or annually to verify cracking pressure accuracy, leakage within specification, and response characteristics. If set pressure drift, abnormal leakage, or sluggish response is observed, arrange for servicing or replacement.