H-4WEH25H6X/6EW110N9TS2K4

The H-4WEH25H6X/6EW110N9TS2K4 directional spool valve is built by Bosch Rexroth for the WEH Directional Spool Valves series. It directs hydraulic flow to actuators in automated machinery where fast switching and high capacity are required. Its nominal size NG25 establishes the port dimensions and flow paths compatible with ISO mounting plates. The porting pattern ISO 4401-08-08-0-05 allows standardized stacking with manifold blocks. A maximum duty flow of 700 l/min permits the valve to serve large cylinders without excessive pressure drop, while a maximum operating pressure of 350 bar on ports A and B supports high-force applications. The permitted viscosity range of 2.8 to 500 mm²/s covers thin startup oils and heavy working fluids, and the fluid temperature window from −20 to +80 °C with NBR seals maintains material integrity under typical ambient and oil cooler conditions. Cleanliness class ISO 4406 (c) 20/18/15 limits particle contamination to protect the precision spool and extend service life.

External pilot oil supply at port X ensures stable actuation when system pressure fluctuates, and internal pilot oil return through port T simplifies piping by sending the pilot flow back to tank. Port T may see pressures up to 250 bar, so the housing and seals are reinforced for back-pressure circuits. The solenoid pilot stage tolerates pilot pressures up to 250 bar and requires at least 18 bar to center the spool, enabling reliable shifting across a wide pressure range. Electrical hookup is through a DIN EN 175301-803 K4 connector, giving a common industrial interface for coil wiring. Two solenoids with pressure centering bring the assembled weight to 19.0 kg, a consideration for mounting fixtures on manifold plates. A mean time to dangerous failure of 100 years (MTTFd) supports functional safety calculations in performance level designs. Together these characteristics make the valve suitable for continuous duty hydraulic automation where predictable control and long life are critical.