Product Overview
The HCG series and HG series are direct-operated pressure control valves based on YUKEN technology. HCG-06-B2-22, HG-03-C3-22, HG-03-B2-22, HCG-06-C4-22, and HCG-03-A1 are typical models within this product family. These valves feature direct-operated construction with hydraulic cushioning, actuated by internal or external pilot pressure.
The HCG series integrates a check valve (non-return) function into the H-type pressure control valve, allowing free reverse flow from the secondary pressure port to the primary pressure port. Depending on the internal assembly configuration, the valve can function as a sequence valve, unloading valve, low-pressure relief valve, pilot-operated check sequence valve, or counterbalance valve (load-holding valve) , enabling sequential actuation control, load holding, and backpressure control for multiple actuators.
The HG series is an H-type direct-operated pressure control valve without the check valve function. Both series share identical mounting dimensions and interfaces, allowing users to select based on whether reverse free-flow capability is required in the circuit.
As a high-cost-performance OEM replacement solution based on YUKEN technology, this valve maintains 100% mechanical and functional interchangeability with the original unit. Every valve undergoes rigorous simulation testing—including pressure cycling, thermal variation, and full-stroke endurance validation—to guarantee factory-grade performance.
Technical Specifications
HCG Series (Subplate Mounting, with Check Valve)：
Brand: YUKEN / High-quality domestic alternative
Valve Type: Direct-operated pressure control valve with check valve (Sequence valve / Counterbalance valve / Pilot-operated check sequence valve)
Design: Direct-operated with hydraulic cushioning mechanism
Actuation: Internal or external pilot pressure control
Mounting Type: Subplate mounting
Mounting Interface: ISO 5781 compliant
Media: Hydraulic oil
Temperature Range: 30–90°C
HCG-03 Series (Size 03 / 10 mm)：
Nominal Size: 03 (approx. 10 mm)
Max. Operating Pressure: 21 MPa (210 bar)
Max. Flow: 50 L/min
Pressure Adjustment Range: A: 1.8–3.5 MPa (18–35 bar); B: 3.5–7.0 MPa (35–70 bar); C: 7.0–14.0 MPa (70–140 bar)
Weight: Approx. 4.0–4.8 kg
HCG-06 Series (Size 06 / 20 mm)：
Nominal Size: 06 (approx. 20 mm)
Max. Operating Pressure: 21 MPa (210 bar)
Max. Flow: 125 L/min
Pressure Adjustment Range: A: 1.8–3.5 MPa (18–35 bar); B: 3.5–7.0 MPa (35–70 bar); C: 7.0–14.0 MPa (70–140 bar)
Weight: Approx. 7.1–7.8 kg
HCG-10 Series (Size 10 / 25 mm)：
Nominal Size: 10 (approx. 25 mm)
Max. Operating Pressure: 21 MPa (210 bar)
Max. Flow: 250 L/min
Pressure Adjustment Range: Same as HCG-03/06
HG Series (Without Check Valve)：
Valve Type: H-type direct-operated pressure control valve
Mounting Type: Subplate mounting
Nominal Size: 03 (10 mm) / 06 (20 mm) / 10 (25 mm)
Max. Operating Pressure: 21 MPa (210 bar)
Max. Flow: HG-03: 50 L/min; HG-06: 125 L/min
Pressure Adjustment Range: Same as HCG series corresponding sizes
Weight: HG-03: Approx. 3.7–4.0 kg
Key Technical Advantages
1. Direct-Operated Construction – Fast and Reliable Response
The direct-operated pressure control design eliminates pilot stage delay for fast response. The integrated hydraulic cushioning mechanism effectively absorbs spool impact, ensuring smooth and reliable shifting.
2. Integrated Check Valve (HCG Series) – Free Reverse Flow Capability
The HCG series integrates a check valve function into the H-type pressure control valve, allowing free reverse flow from the secondary pressure port to the primary pressure port. This design makes it particularly suitable for counterbalance valve and pilot-operated check sequence valve applications requiring reverse free-flow.
3. Multi-Function Valve – Flexible Circuit Adaptation
Through different internal assembly configurations, the same valve body can serve as a sequence valve, unloading valve, low-pressure relief valve, pilot-operated check sequence valve, or counterbalance valve (load-holding valve) . This highly flexible configuration significantly reduces spare parts variety and inventory costs.
4. Internal/External Pilot Options – Versatile Pilot Control
The valve supports both internal and external pilot pressure control. Users can flexibly select based on system pilot oil source configuration to meet diverse hydraulic circuit design requirements.
5. Low Noise Design (≤60 dB) – Improved Working Environment
HCG/HG series features low-noise design with operating noise ≤ 60 dB. Optimized flow path design reduces fluid noise and improves the operator’s working environment.
6. Broad Size Coverage – Versatile Flow Capacity
HCG/HG series covers three sizes: 03 (50 L/min), 06 (125 L/min), and 10 (250 L/min). Pressure adjustment ranges cover A (1.8–3.5 MPa), B (3.5–7.0 MPa), and C (7.0–14.0 MPa), accommodating diverse application requirements from light-duty to heavy-duty operations.
7. Drop-In Interchangeability – Minimized Downtime and Retrofit Costs
The valve strictly adheres to YUKEN’s original mounting dimensions and functional specifications, with ISO 5781 interface compliance. HCG-03 and HG-03 share identical mounting dimensions. Whether for new system design or legacy system upgrades, this valve offers 100% mechanical and hydraulic interchangeability with the original YUKEN unit—eliminating the need for manifold modifications or piping changes, significantly reducing downtime and retrofit expenses.
Application Areas
Sequence Control – Sequential actuation of multiple actuators in injection molding machines, hydraulic presses, and other multi-actuator systems
Counterbalance Valve (Load-Holding) Applications – Preventing load descent in vertical load circuits such as lifting platforms and crane luffing mechanisms, providing backpressure support
Unloading Valve Applications – Automatic unloading when system pressure reaches the set value, reducing energy consumption
Low-Pressure Relief Valve Applications – Serving as a safety valve in low-pressure circuits
Pilot-Operated Check Sequence Valve Applications – Sequence control circuits requiring reverse free-flow
Construction Machinery – Sequence control and load holding for excavators, loaders, and work attachments
Machine Tool Hydraulic Systems – Sequential clamping control for multi-station fixtures
Metallurgical Equipment – Sequence control for rolling mill auxiliary hydraulic systems
Expert Maintenance Tips
1. Fluid Cleanliness Management
HCG/HG series direct-operated pressure control valves feature precision-fitted spool and body construction with specific fluid cleanliness requirements. Recommended filtration accuracy ≤ 10 μm. Maintain system fluid cleanliness to ISO 4406 18/16/13 or better. Contaminants can cause spool sticking, pressure regulation failure, or seal face damage.
2. Pilot Pressure Source Selection Verification
The valve supports both internal and external pilot control. Verify that the system pilot oil source configuration matches the valve model prior to installation—internal pilot type draws oil from port P, while external pilot type requires external pilot pressure introduction. Incorrect pilot configuration will prevent the valve from functioning properly.
3. Pressure Adjustment and Setting
Adjust pressure slowly with the pressure adjustment knob while the system is operating. Verify that the system pressure gauge is functioning properly before adjustment to avoid overshoot and system overload. Different models have different pressure adjustment ranges (A/B/C档)—do not exceed the valve’s rated adjustment range during setting.
4. Installation and Sealing
HCG series features subplate mounting with ISO 5781 interface compliance. Ensure the mounting surface is flat and smooth prior to installation. HCG-03 and HG-03 share identical mounting dimensions for interchangeable installation. Tighten mounting bolts evenly to specified torque. Take care not to damage or omit seals during assembly.
5. Temperature and Viscosity Monitoring
Recommended operating temperature range is 30–90°C. When operating outside this range, select appropriate viscosity hydraulic fluid or implement heating/cooling measures. Pay attention to the effect of fluid viscosity changes on valve response characteristics during cold starts.
6. Periodic Inspection and Maintenance
Regularly verify pressure setpoint stability, response sensitivity, and absence of external leakage. If unstable pressure regulation or sluggish response is detected, inspect pilot oil circuit for blockages, check for spool sticking, or examine spring fatigue. For systems that have been idle for extended periods, perform thorough system circulation filtration before restart.
