EHDFG-01/03 Proportional Directional and Flow Control Valves

I. Core Positioning and Technical Highlights

• Product Type: Direct-acting high-response electro-hydraulic proportional directional and flow control valve, featuring a closed-loop control system with OBE (On-Board Electronics) and LVDT spool position feedback
• Core Advantages:
  • High Response Performance: Close to the performance of simple servo valves; EHDFG-01 is approximately 80Hz/-90° (±25% amplitude), and EHDFG-03 is approximately 50Hz
  • High Precision Control: Closed-loop control provides excellent repeatability and linearity
  • Integrated Design: Built-in power amplifier simplifies wiring, requiring only 24V DC power supply and command signal
  • Multi-Function Integration: A single valve achieves both directional switching and proportional flow regulation

II. Comparison of Key Technical Specifications

III. Model Code Interpretation (Taking EHDFG-01-30-3C40-XY-30 as an Example)

IV. Control Principle and Structural Features

1. Closed-Loop Control Architecture:
   1. Built-in LVDT (Linear Variable Differential Transformer) for real-time spool position detection
   2. Forms a closed loop with the built-in power amplifier to automatically compensate for external interference
   3. Input command signal (usually 0-10V or ±10V) precisely controls spool displacement
2. Structural Design:
   1. Direct-acting design ensures fast response speed and high control precision
   2. Multiple spool types are available (3C2 closed-center type, 3C40, etc.) to adapt to different applications
   3. Built-in manual adjustment screw for easy commissioning and emergency operation

V. Typical Application Fields

• Injection Molding Machines: Precision motion control such as mold clamping, injection, and pressure holding
• Die Casting Machines: Mold opening/closing and injection speed control
• CNC Machine Tools: Worktable positioning and spindle control
• Hydraulic Presses: Slide movement and pressure holding control
• Automated Production Lines: Material handling and precision positioning systems

VI. Usage Notes

1. Fluid Cleanliness: NAS Class 9 or higher is recommended, with a 10μm precision filter installed
2. Oil Temperature Control: The optimal temperature is 20-50°C; avoid high temperatures that affect the service life of seals
3. Electrical Connection: Ensure the connector protection level meets the standard to avoid moisture and dust
4. Commissioning Steps: Perform no-load commissioning first, then gradually increase the load and observe the response characteristics
5. Maintenance Cycle: Regularly check the fluid contamination level and replace the filter element and hydraulic oil according to working conditions

Summary