Basic Information

• Brand: MOOG

• Model: D634‑560

• Series: D634 (Direct Drive Valve, DDV)

• Type: Single‑stage, pilotless, direct‑operated servo valve

• Mounting: ISO 4401‑05 (NG10)Moog Inc.

• Drive: Ultra‑high‑thrust permanent magnet linear force motor (max in D634 series)

• Feedback: Built‑in LVDT spool position closed loop

• Electronics: Integrated 24 VDC PWM drive

• Protection: IP65Moog Inc.

• Weight: Approx. 6.3 kg (13.9 lb)

Hydraulic Specifications

• Max working pressure (P/A/B): 350 bar (5,000 psi)

• Max T‑port pressure (no Y port): ≤50 bar (725 psi)

• Max T‑port pressure (with Y port): 350 bar (5,000 psi)Moog Inc.

• Rated flow (Δp = 35 bar): 240 L/min (63.4 gpm) ← Series maximum

• Peak flow: ≈310 L/min (81.9 gpm)

• Null leakage: 6–14 L/min

• Fluid: ISO 11158 mineral hydraulic oil

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

• Fluid temperature: −20 °C to +80 °C

Electrical Specifications

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

• Max current: 4.0 A (highest in D634‑55x/560)

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

• Connector: 6‑core + PE, IP65Moog Inc.

• Electronics: SMD technology, PWM current output, EMC certified

Dynamic Performance (Typical)

• Full‑stroke step response: ≤45 ms

• −3 dB bandwidth: 5–10 Hz

• Hysteresis: <0.45% of full scale

• Resolution: <0.30% of full scale

• Temperature drift (ΔT = 55 K): <2.5% of full scale

Key Features

• Pilotless direct drive: No pilot oil needed; simpler piping, lower leakage, higher reliabilityMoog Inc..

• Ultra‑high‑flow design: Highest flow in D634 series; optimized for maximum flow in large‑scale hydraulic systems.

• Max‑thrust motor: Delivers the highest force in the D634 lineup; ideal for extreme‑load, high‑flow applications.

• LVDT closed‑loop feedback: Ensures high positioning accuracy and repeatability.

• Spring centering: Fail‑safe return to neutral on power lossMoog Inc..

• Pressure‑independent dynamics: Stable performance under varying loadsMoog Inc..

Applications

• Super‑large hydraulic presses and heavy forging equipment

• Ultra‑high‑tonnage injection molding and die‑casting machines

• High‑force & ultra‑high‑flow vibration test benches

• Heavy‑duty industrial hydraulic systems requiring maximum flow

• Precision position, force & speed closed‑loop control

D634‑55x/560 Series Flow Ranking (L/min @ Δp=35 bar)

• 551: 60

• 552: 80

• 553A: 100

• 554A: 120

• 555: 135

• 557: 150

• 558: 180

• 559: 210

• 560: 240 ← Series peak