I. Core Functions
1. Load-Sensing Control
The DRS valve dynamically adjusts pump displacement by sensing load pressure (LS signal), ensuring system flow matches load demand. For example, in excavator boom operations, the pump reduces displacement under light loads to save energy and increases it under heavy loads for smooth motion.
2. Dynamic Pressure Relief and Throttling
• DRF Type (with orifice): The X port connects to the tank via an internal orifice. When the external directional valve is in neutral, pressure oil in the LS signal line drains back to the tank, maintaining minimal standby flow to prevent energy waste and oil overheating.
• DRS Type (without orifice): The X port is physically isolated from the T (return) port, requiring an external control valve’s drain port for pressure relief. Suitable for systems where downstream valves already integrate drain functionality, simplifying pump design.
3. Pressure Compensation
In multi-actuator systems, the DRS valve ensures independent flow distribution across circuits, preventing interference caused by load variations. For instance, simultaneous operation of an excavator’s bucket and arm maintains preset speeds despite differing loads.
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II. Technical Specifications
【表格】
Parameter Details
Compatible Pump Models Rexroth A10VO, A11VO, and other load-sensing pump series
Control Method Hydraulic control (LS signal)
Pressure Range Up to 350 bar (model-dependent)
Flow Range 10–200 L/min (matched to pump displacement)
Response Time ≤50 ms (rapid adaptation to load changes)
Fluid Temperature -20°C to +80°C (high-temp seals optional)
Filtration Precision ≤10 μm (to prevent internal wear)
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III. Applications
1. Construction Machinery
• Excavators: Control of boom, arm, and bucket movements.
• Cranes: Coordinated luffing, slewing, and hoisting operations.
• Loaders: Hydraulic drive for working attachments.
2. Agricultural Machinery
• Combine harvesters: Header height adjustment and threshing drum speed control.
• Tractors: Hydraulic output for implement suspension.
3. Industrial Equipment
• Hydraulic presses: Precise control of slide speed and pressure.
• Injection molding machines: Flow matching during plasticizing, injection, and holding phases.
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IV. Selection and Maintenance
1. Key Selection Criteria
• System Type: Confirm load-sensing capability (requires DRS valve) or fixed-displacement systems (no load-sensing needed).
• Pump Compatibility: Choose DRS valves matching pump models (e.g., A10VO pump with A10VO-series DRS valve).
• Flow Requirements: Select valve port size (e.g., DN10, DN16) based on maximum actuator flow.
• Pressure Rating: Ensure rated pressure exceeds system peak working pressure.
2. Maintenance Recommendations
• Regular Inspections: Check LS signal line seals every 500 hours to prevent leaks causing control failure.
• Fluid Cleanliness: Maintain oil cleanliness ≤ NAS 6 to avoid orifice blockage.
• Temperature Monitoring: Replace high-temp seals if prolonged operation exceeds 80°C.
• Troubleshooting: For flow fluctuations, prioritize checking DRS valve orifices for clogging or LS springs for fatigue.
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V. Typical Model Examples
• Rexroth A10VO.DRS: For A10VO pumps, features pressure compensation, flow range 10–100 L/min.
• Parker P2145.DRS: Parker’s load-sensing pump valve with ≤30 ms response time, ideal for high-precision systems.
• Sauer PV22.DRS: Designed for Sauer PV pumps, incorporates anti-contamination features for harsh environments.
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VI. Industry Trends
As hydraulic systems evolve toward energy efficiency and intelligence, DRS valves are advancing in the following directions:
1. Electro-Hydraulic Integration: Integration of proportional solenoids for digital flow/pressure control.
2. Lightweight Design: Use of high-strength aluminum alloys reduces weight by over 20%.
3. Smart Diagnostics: Built-in pressure sensors enable real-time valve condition monitoring and predictive maintenance.
