Basic Information

• Brand: MOOG

• Model: D634-539

• Series: D634 (ISO 4401‑05 / NG10)

• Structure: Pilotless, single‑stage, direct‑drive valve

• Drive: Permanent magnet linear force motor

• Feedback: Integrated LVDT spool position closed‑loop

• Power Supply: 24 VDC (18–32 VDC), max. 2.2 A

• Protection Class: IP65

• Weight: Approx. 6.8 kg

• Mounting: ISO 4401‑05 (NG10)

Function & Positioning

Core Functions

• Precise Flow/Direction Control: Four‑way servo control with closed‑loop spool feedback for accurate position, speed, pressure, and force regulation.

• Pilotless Operation: Eliminates pilot oil supply, simplifying circuits, reducing leaks, and improving reliabilityMoog Inc..

• Spring Centering: Automatically returns spool to neutral on power loss for safe shutdownMoog Inc..

• Pressure‑Independent Dynamics: Direct‑drive design ensures stable response regardless of system pressure fluctuationsMoog Inc..

Product Positioning

• Core control component for medium‑to‑high flow, high‑pressure hydraulic systems.

• High‑performance upgrade for traditional pilot‑operated servo valves, offering simpler maintenance, higher stability, and better precision.

• Optimized for 150 L/min nominal flow and 350 bar high‑pressure industrial closed‑loop applications.

Core Performance Parameters

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

• Max. T‑Port Pressure: ≤ 50 bar (without Y port)Moog Inc.

• Rated Flow (Δp = 35 bar): 150 L/min

• Peak Flow: 220 L/min

• Null Leakage: 0.8–4.0 L/min

• Full‑Stroke Step Response: ≤ 20 msMoog Inc.

• ‑3 dB Bandwidth: 40–60 Hz

• Hysteresis: < 0.25% of full scale

• Resolution: < 0.10% of full scale

• Working Fluid: ISO 11158 mineral hydraulic oil

• Fluid Temperature: ‑20 °C to 80 °C

Universal Matching Accessories

• ISO 4401‑05 standard mounting manifold

• M18 6‑core electrical connector

• High‑precision hydraulic filter

• Special sealing kit

• Pressure sensor

Applicable Equipment Fields

• Hydraulic presses and forging machinery

• Injection molding and die‑casting machines

• Vibration and fatigue test benches

• Heavy‑duty industrial hydraulic systems

• Precision automatic closed‑loop control equipment