• • n (Δp=35 bar/land)Moog Inc.

  • 7: Rated pressure 210 bar (max 250 bar)Moog Inc.

  • 1: 3‑way spool, linear, standard overlapMoog Inc.

• D: Revision D, NBR (Buna‑N) seals, basic EMC, 24 VDC supply (legacy version, superseded by E‑series)

Technical Specifications

• Part Number: D635-671D

• Valve Size: NG06 (Cetop 3 / ISO 4401‑03)Moog Inc.

• Control Function: 3‑way pressure control, spring‑centered (fail‑safe: A→T, P→B)Moog Inc.

• Rated Flow (Δp=35 bar/land): 20 L/min (±10% tolerance)Moog Inc.

• Max Flow: 25 L/min

• Operating Pressure:

  • P/A/B ports: 210 bar (3,000 psi)Moog Inc.

  • T port (without Y): 50 barMoog Inc.

  • Y port: Optional (210 bar T)Moog Inc.

• Response Time (0→100% step): ≤18 ms (slower than E‑series)

• Hysteresis: <0.2%Moog Inc.

• Null Shift (ΔT=55 K): <2.0%Moog Inc.

• Linearity: <0.8%Moog Inc.

• Electrical:

  • Supply: 24 VDC (19–32 VDC), 1.0 A maxMoog Inc.

  • Signal: 0–10 V, 0–10 mA, or 4–20 mA (command); 4–20 mA (pressure feedback)Moog Inc.

  • Connector: 6+PE (DIN 43563), IP65 (mated)Moog Inc.

• Fluid: Mineral oil (DIN 51524), viscosity 5–400 mm²/sMoog Inc.

• Temperature:

  • Ambient: −20°C to +50°C (narrower than E‑series)Moog Inc.

  • Fluid: −20°C to +70°CMoog Inc.

• Mass: ~2.5 kgMoog Inc.

• Seals: NBR (Buna‑N, standard temp)

Interface & Communication Configuration

• Electrical Interface: Analog command (0–10 V / 0–10 mA / 4–20 mA) + 24 VDC power; 4–20 mA pressure feedbackMoog Inc.

• Feedback: Integrated pressure sensor (closed‑loop); no external transducer neededMoog Inc.

• Mounting: 4‑bolt NG06 (Cetop 3, M5 screws, 8–10 Nm torque)Moog Inc.

• Porting: P, A, B, T (Y port optional)Moog Inc.

Core Functions

1. Integrated Pressure Control: Onboard sensor + electronics, no external controller requiredMoog Inc.

2. 20 L/min Medium Flow: Balanced flow for general‑purpose pressure controlMoog Inc.

3. 210 Bar Standard Pressure: For medium‑duty hydraulic systemsMoog Inc.

4. Direct‑Drive Linear Motor: No pilot flow, fast response, low hysteresisMoog Inc.

5. Fail‑Safe Spring Center: A→T, P→B on power lossMoog Inc.

6. Revision D: NBR seals, basic EMC, legacy revision (replaced by E‑series)

Application Scenarios

• Industrial Hydraulics: General‑purpose pressure control, low‑to‑medium pressure systemsMoog Inc.

• Test Systems: Medium‑pressure cycling benches, component testingMoog Inc.

• Machine Tools: Standard clamping, low‑load spindle preload controlMoog Inc.

• Hydraulic Presses: Medium‑pressure closed‑loop regulation for light formingMoog Inc.

Compatibility & Key Differences

• Series Compatibility: Interchangeable with D635 2.5/5/10/40 L/min models (same NG06 mounting)Moog Inc.

• D635-671D vs D635-671E:

  • 671D: 20 L/min, 210 bar, NBR seals, −20°C to +50°C, basic EMC (legacy)

  • 671E: 20 L/min, 210 bar, FPM seals, −20°C to +60°C, enhanced EMC (current)

• Replacement: Direct drop‑in upgrade to D635-671E (same performance, better seals/temp range)