Description
D633-471B: Product Overview
The MOOG D633-471B is a direct-drive electrohydraulic servo valve (DDV) designed for precision control of hydraulic actuators in dynamic industrial systems. As part of the D633 Series, it leverages a direct-drive architecture—eliminating the need for a pilot stage—to deliver fast response times and reliable performance in applications requiring accurate position, velocity, or force control.
In automation architectures, the D633-471B serves as the critical interface between electronic controllers (e.g., PLCs, motion controllers) and hydraulic actuators (cylinders, motors). It converts low-power electrical command signals (±10VDC, ±10mA, or 4-20mA) into proportional hydraulic flow and pressure, regulating actuator behavior to maintain stability and precision. The direct-drive design ensures dynamic performance is independent of system pressure, making it suitable for variable-pressure environments.
The D633 Series platform emphasizes robustness and ease of integration. The D633-471B features a spring-centered spool that returns to a neutral position during power loss, preventing unintended actuator movement—a key safety feature for industrial applications. Its compatibility with standard ISO 4401 mounting (sizes 03 and 05) simplifies installation in existing hydraulic systems.
Moog D633-472B
D633-471B: Technical Specifications
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Model Number: D633-471B
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Manufacturer: Moog Inc.
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Product Type: Electrohydraulic Servo Valve (Direct-Drive/DDV)
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Valve Configuration: 4-way spool (symmetrical flow paths, spring-centered)
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Nominal Flow: 5–100 L/min (1.3–26.3 gpm) @ 35 bar (500 psi) differential pressure
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Maximum Pressure: 350 bar (5000 psi) per port
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Input Signal: ±10VDC, ±10mA, or 4–20mA (configurable)
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Response Time: <12 ms (100% step input to 90% flow @ 210 bar)
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Operating Temperature: -20°C to +80°C (fluid-dependent)
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Fluid Compatibility: Petroleum-based oils (ISO VG 32/46), phosphate ester synthetic fluids
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Weight: ~2.5 kg (5.5 lbs, valve body only)
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Dimensions: 152mm (L) x 83mm (W) x 108mm (H) (approximate, ISO 4401 size 03)
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Certifications: CE, ISO 9001 (manufacturing standard)
Core Features & Customer Value
The D633-471B’s direct-drive architecture eliminates the pilot stage, reducing response time to under 12 ms—significantly faster than traditional two-stage servo valves. For engineers managing high-speed systems (e.g., steel mill roll stands, plastic injection molding machines), this minimizes actuator lag, enabling precise control during rapid movements.
With a nominal flow range of 5–100 L/min, the valve adapts to moderate-sized actuators, avoiding the complexity of multi-valve setups. The spring-centered spool ensures safe actuator positioning during power outages, a critical feature for preventing damage to machinery or personnel.
The valve’s compatibility with multiple input signals (±10VDC, ±10mA, 4–20mA) simplifies integration with legacy controllers, reducing the need for signal conversion hardware. For maintenance teams, the robust design resists contamination, extending service life to 15,000+ operating hours with proper filtration.
Moog D633-472B
Typical Applications
The D633-471B is widely used in industrial systems requiring precise hydraulic control:
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Steel Mills: Controls roll stands in hot/cold rolling mills, maintaining consistent strip thickness.
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Plastic Injection Molding: Regulates clamping force and injection speed, ensuring part consistency.
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Hydraulic Presses: Manages ram positioning in metal forming, reducing material waste.
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Aerospace Simulation: Controls actuators in flight simulators, providing realistic response for pilot training.
