Contact Info

D634-1008

Home / Product/ MOOG
D634-1008
May 25, 2026

D634-1008

D634‑1008 is a high‑performance single‑stage direct‑drive servo valve (DDV) in the MOOG D634 series, built for closed‑loop electro‑hydraulic control. It uses a permanent magnet linear force motor to drive the spool directly, with integrated LVDT spool position feedback and 24 VDC PWM electronics. Mounting complies with ISO 4401 Size 05 (NG10). Delivers precise, pressure‑independent flow, direction, and pressure control for industrial machinery.

Description

1.1 Description

D634‑1008 is a high‑performance single‑stage direct‑drive servo valve (DDV) in the MOOG D634 series, built for closed‑loop electro‑hydraulic control. It uses a permanent magnet linear force motor to drive the spool directly, with integrated LVDT spool position feedback and 24 VDC PWM electronics. Mounting complies with ISO 4401 Size 05 (NG10). Delivers precise, pressure‑independent flow, direction, and pressure control for industrial machinery.

1.2 Model Definition

  • D634: ISO 4401 Size 05, direct‑drive, integrated 24 VDC electronics, analog interface servo valve.

  • 1008: Suffix defines coil parameters, LVDT range, seal material, electronic gain/offset, and performance tuning (differs from 1007 in internal calibration and flow‑response mapping).

1.3 Key Features

  • Single‑stage direct drive: no pilot supply needed, better contamination tolerance, simpler system.

  • Pressure‑independent dynamics: consistent response at any system pressure.

  • Integrated EMC‑compliant 24 VDC electronics: reduces external components, simplifies installation.

  • Spring‑centered fail‑safe: spool returns to neutral on power loss, stopping actuators.

  • Low hysteresis & high resolution: hysteresis <0.5%, resolution <0.1% full scale.

  • Low power consumption: reduced current at null and near‑null.

  • 1008 specific: Optimized null stability and lower leakage at mid‑stroke vs 1007.

1.4 Intended Applications

Injection molding, blow molding, die‑casting, hydraulic presses, metal forming, fatigue test rigs, and general industrial servo‑hydraulic systems requiring high dynamic performance and reliability.

2. Technical Specifications

2.1 Hydraulic Data

  • Mounting: ISO 4401 Size 05 (NG10).

  • Max operating pressure (P, A, B): 350 bar (5,000 psi)Moog Inc..

  • Port T pressure: 50 bar (725 psi) without Y port; 350 bar (5,000 psi) with Y portMoog Inc..

  • Rated flow (Δp = 35 bar per land): 60–100 L/min (15.9–26.4 gpm).

  • Maximum flow: approx 185 L/min (48.8 gpm).

  • Internal leakage: ≤0.6 L/min (1008, improved vs 1007 ≤0.8 L/min).

  • Operating fluid: mineral oil per ISO 11158 / DIN 51524 parts 1–3.

  • Recommended viscosity: 15–100 mm²/s; allowable 5–400 mm²/s.

  • Fluid temperature: −20 °C to +80 °C.

  • Fluid cleanliness: ISO 4406 18/15/12 min; 17/14/11 recommended.

2.2 Performance Data

  • Step response (0–100% stroke): typically 10–18 ms (1008); 12–20 ms (1007)Moog Inc..

  • Hysteresis: <0.5% full scaleMoog Inc..

  • Threshold (resolution): <0.1% full scaleMoog Inc..

  • Null shift (ΔT = 55 K): <1.5% (1008, improved vs 1007 <2%).

  • Frequency response (−3 dB): ≥90 Hz (1008); ≥80 Hz (1007)Moog Inc..

2.3 Electrical Data

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

  • Max current consumption: 2.2 A.

  • Recommended fuse: 2.5 A slow‑blow (external).

  • Command signal options: ±10 V, ±10 mA, 4–20 mA (selectable via internal jumper)Moog Inc..

  • Input impedance: >100 kΩ (voltage); 50 Ω (current).

  • Spool position monitor: 0–10 VDC output (standard).

  • Connector: 6+PE (M18), IP65Moog Inc..

  • Ambient temperature: −20 °C to +60 °C.

3. Functional Principle

An analog command signal (±10 V, ±10 mA, or 4–20 mA) goes to the valve’s integrated electronics. The electronics drive a permanent magnet linear force motor to move the spool from spring‑centered neutral. An LVDT measures spool position and feeds it back to the control electronics. The electronics compare command and feedback, adjusting motor drive for precise spool positioning. Spool displacement regulates flow direction (A→B or B→A) and magnitude to the hydraulic actuator.

4. Installation & Wiring

4.1 Mechanical Mounting

Mount on a clean, flat surface per ISO 4401 Size 05. Use supplied O‑rings for port sealing. Torque M8 mounting bolts to 8–10 Nm. Avoid mechanical stress, misalignment, or impact during installation.

4.2 Hydraulic Connections

  • P: Pressure supply

  • T: Tank return

  • A/B: Work ports

  • Y: Optional external drain

Flush system to ISO 4406 17/14/11 before installation. Route Y port directly to tank (no backpressure) if used.

4.3 Electrical Wiring (6+PE Connector)

  • Pin 1: +24 VDC

  • Pin 2: 0 VDC (GND)

  • Pin 3: Command (+)

  • Pin 4: Command (−)

  • Pin 5: Enable (optional)

  • Pin 6: Spool position monitor

  • PE: Protective earth

Use shielded twisted‑pair cables for signals. Connect shield to 0 V (power supply side) and connector housing (EMC).

5. Commissioning

  1. Verify mechanical, hydraulic, and electrical connections before power‑up.

  2. Confirm fluid level and supply voltage (18–32 VDC).

  3. Apply 24 VDC power; valve initializes and performs LVDT self‑test.

  4. Select command signal type via internal jumper.

  5. With zero command, adjust null potentiometer for minimum leakage.

  6. Apply 10%, 50%, 100% step commands to verify smooth response, correct direction, and stability.

6. Operation

  • 0 V / 0 mA / 12 mA: spool centered, no flow.

  • +10 V / +10 mA / 20 mA: full flow A→B.

  • −10 V / −10 mA / 4 mA: full flow B→A.

  • Monitor pin: 0–10 VDC proportional to spool stroke (diagnostics).

7. Maintenance & Troubleshooting

7.1 Maintenance

  • Monthly: inspect for external leakage and loose connections.

  • Replace filters regularly to maintain ISO 4406 18/15/12 cleanliness.

  • Use genuine MOOG O‑rings for seals.

  • Do not disassemble internal components; contact MOOG or authorized service centers for repair.

7.2 Troubleshooting

  • No response: check 24 VDC power, wiring, and command signal.

  • Slow response: verify system pressure, fluid viscosity, and filtration.

  • Oscillation/instability: improve shielding, adjust controller gains, check grounding.

  • External leakage: replace worn O‑rings with genuine MOOG parts.

8. Ordering Information

  • Model: D634‑1008

  • Series: D634 (Direct Drive Servo Valve)

  • Mounting: ISO 4401 Size 05 (NG10)

  • Electronics: 24 VDC integrated, analog interface

  • Feedback: LVDT closed‑loop spool position control


Get a Quote

Search

Categories

pages