1. Basic Identification

• Model: D633-599B

• Brand: MOOG (USA)

• Category: Direct-Drive Electro-Hydraulic Servo Valve (DDV)

• Alias: Direct-Operated Servo Valve, Integrated Electronic Servo Proportional Valve, D633 Series High-Pressure Servo Valve

• Model Code Definition:

  • D633: Series (ISO 4401 Size 03/NG6, direct drive)

  • 599: Flow/pressure/configuration code (nominal flow ≈ 40 L/min)

  • B: Seal/interface variant (HNBR seal, M12 connector)Moog Inc.

2. Basic Information

• Structure: Permanent magnet linear force motor directly drives the spool, no pilot oil, integrated electronic closed-loop controlMoog Inc.

• Mounting Standard: ISO 4401-03-03-0-94 (NG6)Moog Inc.

• Weight: Approx. 2.6 kg

• Protection Class: IP67 (connector), IP65 (valve body)

• Temperature Range: Ambient -20 ℃～+60 ℃; Fluid -20 ℃～+70 ℃

3. Function & Positioning

• Core Function: 4/3-way direction, speed, pressure, force closed-loop control; throttling flow controlMoog Inc.

• Positioning: Core control component for industrial high-pressure, high-dynamic, high-precision electro-hydraulic systems; replaces traditional pilot-operated servo valvesMoog Inc.

• Key Features:

  • Pressure-independent dynamic performance, fast responseMoog Inc.

  • Spring-centered on power failure, high safety redundancyMoog Inc.

  • Low null current, low hysteresis (≤0.2%)

4. Core Performance Parameters

• Hydraulic Parameters

  • Rated Flow: 40 L/min (at Δp=35 bar per edge)

  • Max Working Pressure: 350 bar (P/A/B ports); 50 bar (T port)

  • Fluid Type: Mineral hydraulic oil (ISO 4406 18/15/12)

  • Viscosity: 15–100 mm²/s (operational); 5–400 mm²/s (allowable)

• Electrical Parameters

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

  • Control Signal: ±10 V, ±10 mA, 4–20 mAMoog Inc.

  • Feedback Signal: 4–20 mA

  • Max Current Consumption: ≤1.2 A

  • Electrical Connector: M12 (6+PE pins)Moog Inc.

• Performance

  • Step Response (0–100%): ≤12 ms

  • Hysteresis: ≤0.2%

  • Linearity: ≤0.1%

  • Resolution: ≤0.05%

5. General Matching Accessories

• M5 Grade 10.9 mounting bolts

• OEM HNBR sealing kits

• 5-core shielded cable (M12 compatible)

• 10 μm high-pressure hydraulic filter

• M12 waterproof connector (male/female)

6. Applicable Industries & Equipment

• Metal forming machinery (presses, stamping lines)

• Injection molding & die-casting machines

• Metallurgical rolling & continuous casting equipment

• Aerospace test benches & simulators

• Industrial robot hydraulic units

• Vibration & fatigue testing systems

• Heavy-duty automation hydraulic control systems