Product Overview
The ZDR6DB2-4X/150YM (Material Number R900431172) is a classic model in the Bosch Rexroth ZDR series of direct-operated pressure reducing valves in sandwich plate design, NG6 (CETOP 3) size, with mounting pattern conforming to ISO 4401-03-02-0-05. The valve is used to reduce system pressure to a set value and limit the secondary circuit pressure. It basically comprises the housing, control spool, compression spring, adjustment type, and an optional check valve.
The ZDR6DB2-4X/150YM is the B-port reducing version—pressure reduction is effected in channel B. The ZDR6DP2-4X/150YM (Material Number R900483787) is the P-port reducing version. Both models belong to the 4X Component Series (40–49) with stable installation and connection dimensions. The pressure adjustment range is up to 150 bar, suitable for various industrial hydraulic systems requiring precise secondary circuit pressure control.
As an original Bosch Rexroth direct-operated pressure reducing valve, this product offers complete interchangeability within the same series and size, requiring no modifications to mounting interfaces or piping layouts.
Technical Specifications
Model: ZDR6DB2-4X/150YM
Material Number: R900431172
Brand: BOSCH REXROTH
Series: ZDR Series, 4X Component Series (40–49)
Product Type: Direct Operated Pressure Reducing Valve in Sandwich Plate Design
Nominal Size: NG6 (6 mm)
Mounting Standard: ISO 4401-03-02-0-05 / CETOP 3
Maximum Operating Pressure: 315 bar (4568 psi)
Maximum Flow Rate: 50 L/min (13.2 GPM)
Pressure Adjustment Range: Up to 150 bar (2175 psi)
Pressure Reduction Channel: B-port — ZDR6DB2-4X/150YM
Adjustment Type: Sleeve with hexagon and protective cap
Optional Check Valve: Not equipped (this model)
Seal Material: NBR
Hydraulic Fluids: HL, HLP, HLPD, HVLP, HVLPD, HFC mineral oils
Operating Temperature Range: -30°C to +80°C (NBR seals)
Viscosity Range: 10–800 mm²/s
Installation Position: Any
Weight: Approx. 1.2–1.44 kg
Key Technical Advantages
1. Direct-Operated Design for Fast Response
The ZDR6DB2-4X/150YM features direct-operated control spool construction. Compared to pilot-operated pressure reducing valves, the direct-operated design eliminates the pilot stage for faster response, particularly suitable for hydraulic systems requiring rapid pressure adjustment.
2. Sandwich Plate Design for Compact Integration
The sandwich plate design allows direct installation between the directional valve and subplate. This eliminates additional piping, significantly simplifies hydraulic system layout, reduces potential leak points, and saves installation space. The mounting pattern conforms to ISO 4401-03-02-0-05.
3. B-Port Reducing for Flexible Circuit Adaptation
This model is the B-port reducing version—pressure reduction is effected in channel B. The ZDR series also offers A-port (DA series) and P-port (DP series) reducing versions, allowing flexible selection based on system requirements.
4. 4 Pressure Grades Available for Precise Matching
The ZDR series offers 4 pressure grades: 25, 75, 150, and 210 bar. The ZDR6DB2-4X/150YM provides an adjustment range up to 150 bar, enabling precise selection based on actual system working pressure. 4 adjustment types are available: rotary knob, sleeve with hexagon and protective cap, lockable rotary knob with scale, and rotary knob with scale.
5. 315 bar High Pressure and 50 L/min High Flow Capacity
Delivers 315 bar (4568 psi) maximum operating pressure and 50 L/min (13.2 GPM) flow capacity in a compact NG6 package. Operating temperature range covers -30°C to +80°C, suitable for various industrial hydraulic systems.
6. International Standard Compliance for Global Interchangeability
Mounting conforms to ISO 4401-03-02-0-05 international standards. Fully compatible with globally adopted NG6 size interfaces for direct replacement of same-series, same-specification products.
Application Areas
Injection Molding Machinery — Precise secondary pressure control for injection and clamping circuits
Hydraulic Presses and Forging Equipment — Pressure switching and regulation for slide advance and return
CNC Machine Tools — Precise pressure control for hydraulic clamping and unclamping
Industrial Automation Production Lines — Various applications requiring main system pressure reduction for sub-circuits
Test Benches and Test Equipment — Precision pressure regulation and control
General Industrial Hydraulic Systems — Various hydraulic circuits requiring precise pressure control
Expert Maintenance Tips
1. Installation Guidelines
Mounting surface must conform to ISO 4401-03-02-0-05 standards.
ZDR6DB2-4X/150YM features sandwich plate design—install between the directional valve and subplate. Pay attention to sealing and bolt length between stacked valve layers.
Thoroughly clean the mounting surface and all ports before installation to prevent foreign particles from entering and causing spool sticking or seal damage.
Installation position: Any.
2. Hydraulic Fluid Management
Compatible fluids: HL, HLP, HLPD, HVLP, HVLPD, HFC.
Seal material: NBR. For phosphate ester and other specialty fluids, select FKM seal option.
Operating temperature range: -30°C to +80°C.
Viscosity range: 10–800 mm²/s.
Recommended fluid cleanliness: ISO 4406 20/18/15.
Install a return line filter with minimum 10 μm filtration rating.
3. Pressure Setting Adjustment
ZDR6DB2-4X/150YM adjustment range: Up to 150 bar.
Pressure adjustment is performed via the sleeve with hexagon and protective cap.
Adjust gradually under system operating conditions to achieve the desired pressure value.
For adjustment types with lockable rotary knob with scale or rotary knob with scale, select corresponding configuration models.
4. Periodic Maintenance Inspection
Inspect the valve body for external oil leakage every 2,000 operating hours or at least annually.
If reduced pressure instability or slow response is observed, first check system fluid cleanliness and verify the control spool is not sticking.
Periodically check that the spring chamber leakage oil drain channel is clear.
