Spool hydraulic directional control valve D638

electrically-operateddirect-operatedelectro-hydraulic

Product description
The D638 and D639 series are direct-operated servo valves with an integrated amplifier, a built-in pressure transducer and an optional fieldbus interface. They use a permanent-magnet linear motor for direct drive of the spool, eliminating the need for pilot oil. Available in ISO 4401 mounting patterns: size 03 (D638) and size 05 (D639).

Key features
Designed for demanding industrial applications, these servo valves deliver pressure-independent dynamics, high control force and low electrical consumption near the hydraulic null point. Integrated electronics and sensor options enable versatile control strategies for pressure, flow and axis functions.

Features

• Direct drive with permanent-magnet linear motor: no pilot oil required
• Pressure-independent dynamic response
• High control force without flow limiting
• Low current consumption at or near hydraulic null
• Spring-centred spool on power loss: actuator remains in safe centred position
• Integrated amplifier and control electronics with built-in pressure transducer
• Optional fieldbus interface and additional analogue inputs for external sensors

Specifications
Models: D638 (ISO 4401 size 03), D639 (ISO 4401 size 05)
Nominated flow (ΔpN = 35 bar): up to 40 l/min (D638), up to 100 l/min (D639)
Maximum flow: 75 l/min (D638), 180 l/min (D639)
Max. operating pressure (ports P, A, B): 350 bar
Port T without Y: 50 bar
Port T with Y: 350 bar (D638), 210 bar (D639)
Step response (0–100%): 8 ms (D638), 14 ms (D639)
Supply voltage: 24 V DC (18–32 V DC)
Command signal options: ±10 V, ±10 mA, 4–20 mA
Electrical interfaces: 6+PE or 11+PE connectors
Integrated sensors: built-in pressure transducer (A port); optional A, B & P transducers

Resources
Technical catalogues, installation drawings and firmware/interface manuals are available in the product documentation.