1. Product Brief

2. Basic Information

• Brand: MOOG

• Model: D634-501A

• Type: Pilotless electro-hydraulic direct-drive servo valve

• Mounting: ISO 4401-05 (NG10)

• Actuation: Permanent magnet linear force motor (no pilot oil required)

• Power Supply: 24 VDC (18–32 VDC operating)Moog Inc.

• Feedback: Integrated LVDT spool closed-loop control

• Reset: Spring centering (failsafe to neutral on power loss)

• Protection: IP65

• Weight: ~2.5 kg

• Connector: M18 6-pin + PE

3. Function & Positioning

• Core Function: Precise flow/direction control via analog signals; closed-loop control of position, velocity, pressure, force. Excellent repeatability, low hysteresis, and pressure-independent dynamic response.

• Positioning: Medium-flow, high-precision model in D634 series; ideal for applications requiring accuracy and dynamic performance without ultra-high flow.

4. Core Performance Parameters

Hydraulic Parameters

• Max working pressure (P/A/B): 350 bar

• Max T-port pressure: ≤50 bar (without Y port); ≤350 bar (with Y port)

• Rated flow @35 bar Δp: 100 L/min

• Null leakage: 0.15–1.2 L/min

• Fluid: ISO 11158 mineral oil

• Fluid temperature: −20°C to 80°C

• Cleanliness: ISO 4406 17/14/11

Dynamic Parameters

• Full-stroke step response: ≤12 ms

• −3 dB bandwidth: 40–60 Hz (at 140 bar)

• Hysteresis: <0.2% full scale

• Resolution: <0.1% full scale

• Temperature drift (ΔT=55K): <1.5% full scale

Electrical Parameters

• Control signal: ±10 VDC (standard); ±10 mA / 4–20 mA (optional)Moog Inc.

• Feedback signal: 0–10 VDC

• Ambient temperature: −20°C to 60°C

• Certification: CE compliant

5. Matching Accessories

• Shielded twisted signal cable

• M18 waterproof connector

• ISO 4401-05 standard valve mounting base

• High-precision hydraulic filter

• 24 VDC low-ripple stabilized power supply

• Servo controller, displacement/pressure sensors

6. Application Fields

• Precision injection molding & blow molding machines

• Material fatigue & strength test benches

• High dynamic vibration simulation equipment

• Wind turbine pitch control systems

• Medium-duty forging & extrusion hydraulic presses