D634-373C
May 25, 2026

D634-373C

D634-373C is a direct drive servo valve of MOOG D634 series with ISO 4401 Size 05 mounting layout. Permanent magnet linear force motor drives the spool directly with no pilot oil required. Built-in LVDT sensor performs closed-loop spool position control to secure high precision and repeatability. Dynamic performance keeps stable under varying working pressure. Spring centering design returns spool to neutral position automatically when power fails, realizing reliable fail-safe function. This valve is designed for heavy-duty industrial closed hydraulic control.

Description

1. General Description

D634-373C is a direct drive servo valve of MOOG D634 series with ISO 4401 Size 05 mounting layout. Permanent magnet linear force motor drives the spool directly with no pilot oil required. Built-in LVDT sensor performs closed-loop spool position control to secure high precision and repeatability. Dynamic performance keeps stable under varying working pressure. Spring centering design returns spool to neutral position automatically when power fails, realizing reliable fail-safe function. This valve is designed for heavy-duty industrial closed hydraulic control.

2. Model Definition

D634: Direct drive servo valve series
373: Medium high flow and medium dynamic configuration
C: Revision version C

3. Hydraulic Specifications

Mounting standard: ISO 4401 Size 05 (NG10)
Max working pressure of P, A, B ports: 350 bar
Max pressure of T port: 50 bar
Rated flow at 35 bar pressure drop: 140 L/min
Maximum flow rate: approximately 210 L/min
Internal leakage: ≤3.0 L/min
Applicable fluid: ISO 11158 standard mineral oil
Fluid temperature range: -20 °C ~ +80 °C
Required fluid cleanliness: ISO 4406 17/14/11
Total weight: approximately 7.1 kg

4. Dynamic Performance

Full stroke step response: ≤21 ms
-3dB frequency bandwidth: 50~60 Hz
Hysteresis: less than 0.28% full scale
Position resolution: less than 0.14% full scale
Null drift under 55K temperature change: less than 1.6% full scale

5. Electrical Specifications

Supply voltage: 24 VDC, working range 18~32 VDC
Maximum operating current: 2.9 A
Standard control signal: ±10 V
Optional signal: ±10 mA, 4-20 mA
Spool position feedback output: 0-10 VDC
Connector type: M18, 6 pins with PE terminal, IP65 protection grade
Ambient temperature: -20 °C ~ +60 °C
EMC certification: CE compliant

6. Key Features

Pilotless structure for easy installation and maintenance
Medium high flow capacity satisfies heavy load driving demand
Pressure independent dynamic property ensures steady operation
High precision closed-loop control delivers accurate motion adjustment
Fail-safe spring reset protects whole system against power outage
Integrated electronic drive unit features compact and durable structure

7. Application Scope

Heavy industrial hydraulic press equipment
Large material fatigue testing machines
Medium speed high force vibration simulation platforms
Industrial position, velocity and pressure closed-loop hydraulic control system

8. Pin Assignment

Pin 1: +24 VDC power
Pin 2: Power ground
Pin 3: Command signal positive
Pin 4: Command signal negative
Pin 5: Position feedback output
Pin 6: Feedback ground
PE: Protective earth
Shielded twisted pair cable is recommended for signal wiring


Get a Quote