SUN Hydraulics Pressure Reducing Valve | CXDA-XAN CSAB-XXN PVHB-LAN | Cartridge Valve

Chengyuan Hydraulic offers high-performance replacement solutions for SUN Hydraulics pressure control valves, including Reducing Valves (CXDA, CSAB), Proportional Reducing Valves (PVHB), and combined Reducing/Relieving Valves (CNDC, CNCD, CXIE). These valves are critical components for maintaining a constant downstream pressure in hydraulic sub-circuits. Chengyuan strictly adheres to SUN’s signature “Floating Construction” design philosophy, allowing the valve sleeve to “float” radially within the manifold cavity. This design eliminates spool binding issues caused by machining inaccuracies or excessive installation torque. All models are 100% Drop-in Interchangeable and undergo 100% Simulation Load Testing to guarantee that pressure regulation precision and response frequency meet the highest industrial standards.

Technical Specifications 

• CXDA-XAN: Proportional Reducing/Relieving Valve, T-13A cavity, 350 bar max inlet pressure, 40 L/min max flow.

• CSAB-XXN: Direct-acting Reducing/Relieving Valve, T-11A cavity, 350 bar max inlet, 10 L/min flow.

• PVHB-LAN: Electro-proportional Reducing/Relieving Valve, T-11A cavity, 15 L/min flow, control pressure up to 210 bar.

• CNBC-XCN: Pilot-operated Reducing Valve, T-2A cavity, 350 bar max inlet, 160 L/min high flow.

• CNDC-XCN: Pilot-operated Reducing/Relieving Valve, T-2A cavity with relief function to protect actuators, 160 L/min.

• CNCD-XCN: High-flow Pilot-operated Reducing/Relieving Valve, T-10A cavity, 40 L/min flow capacity.

• CXIE-XCN: Proportional Reducing/Relieving Valve, T-19A cavity for large-scale systems.

• Adjustment Options: X (Stainless steel screw), L (Manual adjustment with cover).

Key Technical Advantages:

• Floating Sleeve Technology: The self-aligning assembly minimizes sensitivity to manifold cavity concentricity errors, ensuring highly sensitive spool movement even under extreme temperature fluctuations.

• Excellent Dynamic Stability: Precisely calibrated internal damping orifices suppress pressure oscillations during the reduction process, maintaining a steady downstream output despite drastic fluctuations in inlet flow.

• High Volumetric Efficiency: Hardened alloy steel seats are precision-lapped to micron tolerances, achieving internal leakage rates far below the industry average, which reduces standby energy loss.

• Fatigue & Impact Resistance: Constructed from high-strength ductile iron or alloy steel and validated through 100% load-cycle testing, ensuring a service life of millions of cycles at 350 bar.

Application Areas:

• Machine Tools: Used in low-pressure sub-circuits for chuck clamping and tailstock control.

• Mobile Machinery: Provides constant pilot pressure for excavators, loaders, and other heavy equipment control systems.

• Automated Production Lines: Manages pressure staging for individual actuators in multi-station synchronized motions.

• Hydraulic Integrated Circuits (HIC): Serves as a standard cartridge insert for pressure management in custom manifold blocks.

Expert Maintenance Tips:

• Strict Torque Compliance: Always use a torque wrench and follow the SUN technical manual’s specified settings. Excessive torque can damage O-rings or cause permanent sleeve distortion.

• Oil Cleanliness: Due to the fine pilot orifices, maintain a system cleanliness of at least ISO 4406 18/16/13 to prevent regulation failure.

• Pre-start Setting: Loosen the adjustment screw before system startup. Once the pump is running, gradually tighten it to the desired pressure to avoid initial high-pressure surges to the actuators.