1. Product Brief

2. Basic Information

• Brand: MOOG

• Model: D634-399C

• Category: Electro-hydraulic direct-drive servo valve (DDV, pilotless)

• Mounting Standard: ISO 4401-05 (NG10)Moog Inc.

• Drive Mode: Permanent magnet linear force motor direct drive, no pilot oil supply requiredMoog Inc.

• Power Supply: 24 VDC (18–32 VDC) integrated PWM driveMoog Inc.

• Feedback: Built-in LVDT spool position closed-loop

• Reset: Spring centering, auto-return to neutral on power lossMoog Inc.

• Protection Class: IP65 (valve body)

• Weight: ≈ 11.5 kg

• Alias: Ultra-high-flow direct-drive servo valve, high-pressure DDV servo valve

3. Function & Positioning

• Core Function: Accepts ±10 V/±10 mA/4–20 mA analog signals to achieve high-precision flow and direction dual control, enabling closed-loop regulation of position, velocity, pressure, and force. The pilotless design ensures zero pilot leakage, strong contamination resistance, and pressure-independent dynamic performanceMoog Inc..

• Product Positioning: The top-tier ultra-high-flow, high-response model in the D634 series. It replaces multi-stage servo valve assemblies and is ideal for 350 bar high-pressure, 550 L/min-class flow, and ultra-high-frequency dynamic extreme heavy-duty applications, such as heavy forging, high-pressure extrusion, and large structural test benches.

4. Core Performance Parameters

Hydraulic Parameters

• Max Working Pressure (P/A/B): 350 bar (5,000 psi)Moog Inc.

• Max T-Port Pressure: ≤ 50 bar (without Y-port); ≤ 350 bar (with Y-port)Moog Inc.

• Rated Flow @ 35 bar Pressure Drop: 530–550 L/min

• Peak Flow: ≈ 680 L/min

• Null Internal Leakage: ≤ 10.0 L/min

• Applicable Fluid: ISO 11158 standard mineral oil

• Fluid Temperature: -20 °C to 80 °C

• Fluid Cleanliness: ISO 4406 17/14/11

Dynamic Parameters

• Full-Stroke Step Response: ≤ 11 ms

• -3 dB Frequency Bandwidth: 100–110 Hz

• Hysteresis: ＜ 0.15% full scale

• Control Resolution: ＜ 0.05% full scale

• Temperature Drift: ＜ 0.7% full scale

Electrical Parameters

• Max Operating Current: 6.5 A

• Standard Control Signal: ±10 VDCMoog Inc.

• Optional Signals: ±10 mA, 4–20 mAMoog Inc.

• Spool Position Feedback: 0–10 VDC

• Connector: M18 6-pin with PE terminal

• Ambient Temperature: -20 °C to 60 °C

• Certification: CE compliant

5. Matching Accessories

• Shielded twisted-pair signal cable

• M18 waterproof connector

• ISO 4401-05 standard valve mounting baseMoog Inc.

• High-precision hydraulic filter

• 24 VDC low-ripple regulated power supplyMoog Inc.

• Servo controller, displacement sensors, pressure sensors

6. Application Fields

• Heavy forging, extrusion, and high-pressure hydraulic machinery

• Large-scale aerospace and automotive structural test benches

• High-load vibration testing and motion simulation equipment

• Marine and offshore engineering hydraulic systems

• High-end hydraulic control systems for wind power and large construction machinery