ELDFG-03EH-80 Yuken Proportional Directional Valve 80 L/min

Product Overview

The ELDFG-03EH series direct-operated high-response proportional electro-hydraulic directional and flow control valve (model ELDFG-03EH-80-3C2L-XY-CD-10) is manufactured to original YUKEN technical standards. Belonging to the ELDFG series with size 03 (NG10 / CETOP 5 / ISO 4401-05), this valve is a high-performance closed-loop proportional directional and flow control valve. Featuring a direct-operated subplate mounting design with integrated on-board electronics (OBE) and spool position electrical feedback (differential transformer LVDT), the proportional solenoid directly drives the spool for continuous, precise high-response proportional control of both direction and flow magnitude.

The ELDFG-03EH-80-3C2L employs spool type 3C2L (zero lap, 2% overlap linear flow gain type), with linear no-load flow characteristics, ideally suited for mechanical position control and pressure control. The rated flow is 80 L/min (at Δp = 1 MPa valve pressure drop) with maximum operating pressure of 31.5 MPa and allowable tank port back pressure of 21 MPa. The valve integrates directional control and flow control into a single unit with high response, high accuracy, and high reliability closed-loop control characteristics. It can be used as a replacement for simplified servo valves in precision hydraulic control applications.

This product is dimensionally and functionally identical to the original YUKEN ELDFG-03EH series valve, with a mounting surface conforming to ISO 4401-05-04-0-94, offering true drop-in interchangeability for direct replacement of same-specification OEM valves. Every unit undergoes 100% bench testing under simulated working conditions, including rated pressure holding, spool position accuracy, flow linearity, and dynamic response characterization.

Technical Specifications

General Specifications

• Model: ELDFG-03EH-80-3C2L-XY-CD-10

• Product Series: ELDFG-03EH (Size 03 / NG10 / CETOP 5 / ISO 4401-05)

• Design Number: 10 design

• Spool Type: 3C2L (Zero lap, 2% overlap linear flow gain type)

• Design: Direct-operated subplate mounting closed-loop proportional directional and flow control valve with integrated on-board electronics (OBE)

• Mounting Pattern: ISO 4401-05-04-0-94 (NG10)

• Installation Position: Any (must be within ±15° of horizontal plane)

Hydraulic Parameters

• Rated Flow: 80 L/min (at Δp = 1 MPa valve pressure drop, 4-way valve)

• Maximum Operating Pressure: 31.5 MPa (315 bar / 4570 psi)

• Allowable Tank Port Back Pressure: 21 MPa (210 bar / 3045 psi)

• Valve Pressure Drop: 1.5 MPa (at rated flow); 1 MPa (at 4-way valve rated flow)

• Hydraulic Fluid: Mineral-based hydraulic oil (per ISO 6743-4)

• Viscosity Range: Recommended 15 – 100 mm²/s, allowable 10 – 400 mm²/s

• Fluid Temperature Range: -20°C to +70°C

• Filtration: ISO 4406 18/16/13

Electrical Parameters

• Supply Voltage: 24 VDC

• Command Signal: ±10 V voltage input / 4-20 mA current input / 0-±10 mA current input (multi-signal compatible)

• Rated Current: Max. 3 A

• Coil Resistance: 3 Ω (at 20°C)

• Power Consumption: Max. 27 W

• Integrated Electronics: OBE (On-Board Electronics), integrated on-board amplifier

• Electrical Connector: 6+PE (per EN 175201-804, electrical plug not included; Yuken part number TK290457-1)

• Protection Class: IP65

• Hysteresis: ≤ 0.1%

• Repeatability: ≤ 0.1%

• Step Response (0→100%): 25 ms (3C2L spool)

• Step Response (100→0%): 23 ms (3C2L spool)

• Frequency Response (-90° phase): 41 Hz (3C2L spool)

Materials & Construction

• Valve Body: High-strength cast iron

• Control Spool: Carburized steel, precision ground

• Seals: NBR (standard)

• Mounting Bolts: M6×35L (grade 12.9), 4 pcs, tightening torque 13-16 Nm

Weight

• Weight: approx. 7.5 kg (16.5 lbs)

Key Technical Advantages

1. Closed-Loop Control with Servo Valve Level Response
The ELDFG-03EH-80-3C2L employs closed-loop control design with real-time monitoring and feedback control of the spool position via a differential transformer (LVDT). The ELDFG-03EH achieves frequency response of 50 Hz/-90° (±25% amplitude), and in the 3C2L spool configuration, step response (0→100%) is only 25 ms, delivering dynamic response approaching simple servo valve levels. The valve can directly interchange with simple servo valves for position and pressure control, achieving precision hydraulic control in a more cost-effective manner.

2. Integrated OBE Electronics for Simplified System Architecture
The valve integrates the proportional amplifier directly into the valve body (On-Board Electronics). Users need only provide 24 VDC power supply and a command signal to achieve high-accuracy, fast-response hydraulic system operation. The integrated design significantly reduces external wiring and cabinet space requirements while minimizing electromagnetic interference on signal transmission. Multiple command signal inputs are supported including ±10 V, 4-20 mA, and 0-±10 mA, compatible with mainstream motion controllers without requiring an external amplifier.

3. Newly Developed Compact High-Force Solenoid with Excellent Contamination Resistance
The valve employs a newly developed compact high-force solenoid combined with a differential transformer for spool position detection in a closed-loop configuration, achieving high response and high accuracy with excellent contamination resistance. The powerful solenoids provide excellent resistance to particulate contamination in the hydraulic fluid, effectively reducing problems caused by oil contamination and lowering filtration costs. This makes the valve particularly suitable for industrial field environments.

4. 3C2L Zero Overlap Spool with Linear Flow Characteristics
The 3C2L spool features zero overlap (zero lap) design with 2% overlap linear flow gain characteristics. The no-load flow characteristics are linear, making it the ideal choice for mechanical position control and pressure control. The control spool is precision-ground from carburized steel with micron-level clearance control, with hysteresis ≤ 0.1% and repeatability ≤ 0.1%, meeting the demanding requirements of high-accuracy closed-loop control applications for spool position accuracy.

5. 100% Simulated Working Condition Testing and Drop-in Interchangeability
Every ELDFG-03EH-80-3C2L-XY-CD-10 valve undergoes 100% bench testing prior to shipment, covering 31.5 MPa rated pressure holding, spool position accuracy calibration, flow-signal linearity verification, internal leakage measurement, and dynamic response characterization. Mounting dimensions, port positions, electrical interfaces, and performance curves are strictly matched to the original YUKEN valve, with a mounting surface conforming to ISO 4401-05-04-0-94, enabling direct drop-in replacement without modifying piping or control programs.

Application Areas

• Construction Machinery: Precision direction and flow control for excavator and crane hydraulic systems

• Plastic Machinery: Proportional control of injection speed and holding pressure for injection molding and extrusion machines

• Machine Tools: CNC hydraulic clamping systems, feed control, position control

• Metallurgical Equipment: Precision control for continuous casting machines and rolling mill auxiliary hydraulic systems

• Presses: Proportional speed and direction regulation for hydraulic presses

• Material Testing Machines: Force-displacement closed-loop control for loading systems

• Precision Control Systems: Applications replacing simple servo valves for position and pressure control

Expert Maintenance Tips

Installation Guidelines

1. The ELDFG-03EH series must be installed within ±15° of the horizontal plane. The axis L-L’ must be within approximately ±15° of the horizontal plane during installation. Mounting surface flatness must be ≤ 0.05 mm. Use 4 pcs M6×35L hexagon socket head cap bolts (grade 12.9) with tightening torque of 13-16 Nm, tightened diagonally in stages. The mounting surface conforms to ISO 4401-05-04-0-94 for direct installation on standard subplates or manifolds.

2. Thoroughly flush all piping circuits before installation. Ensure no welding slag, metal chips, or particulate contaminants remain. Prior to first operation, circulate the system through a 10 μm filter element for a minimum of 30 minutes. Recommended fluid cleanliness is ISO 4406 18/16/13 or better.

3. Electrical connections must use a 6+PE connector conforming to EN 175201-804 (electrical plug not included; Yuken part number TK290457-1) to maintain IP65 protection. Control signal cables should be shielded, with the shield grounded at one end to prevent electromagnetic interference causing spool oscillation.

4. Zero Point Adjustment: For NULL adjustment, remove the protection screw and rotate the internal trimmer. After adjustment, always reinstall the protection screw.

Routine Maintenance Procedures

1. Fluid Cleanliness Management: Maintain system fluid cleanliness at ISO 4406 18/16/13 or better. Check fluid particulate contamination every 500 operating hours and replace filter elements and hydraulic fluid when contamination exceeds limits. The valve features powerful solenoids with strong contamination resistance, but maintaining fluid cleanliness remains key to extending service life.

2. Electrical Zero Point Verification: Periodically check the electrical zero point for drift with the power supply disconnected. If zero point deviation exceeds ± 2%, re-calibrate via the potentiometer on the OBE electronics (remove the protection screw first).

3. Coil Resistance Verification: Measure solenoid coil resistance (standard value 3 Ω @ 20°C) every 1,000 operating hours. Replace the coil if deviation exceeds ± 10%. Rated current is max. 3 A with max. power consumption of 27 W; monitor for abnormal temperature rise.

4. Internal Leakage Monitoring: Due to the design principle, proportional valves have inherent internal leakage. An annual internal leakage test is recommended. If leakage exceeds 150% of the factory standard, seal replacement should be scheduled.

5. Installation Orientation Maintenance: The valve has installation orientation restrictions and must be installed within ±15° of the horizontal plane. When inspecting or reinstalling, ensure the installation orientation meets requirements to avoid spool performance abnormalities caused by improper installation.