H-4WEH25C6X/6EG12N9K4

The H-4WEH25C6X/6EG12N9K4 directional spool valve is produced by Bosch Rexroth within the WEH Directional Spool Valves series. Designed to route hydraulic flow in automation circuits, it relies on electro-hydraulic actuation so the main spool shifts when a solenoid-operated pilot stage energizes. The NG25 size establishes a 25 mm port diameter that supports medium-to-high flow rates in industrial presses and mobile equipment. A 4-way flow path configuration lets the unit alternately connect pressure and return lines to two working ports for bidirectional cylinder control. The ISO 4401 porting pattern arranges all four ports in a standardized footprint, simplifying stack mounting on sub-plates. An external pilot oil supply, identified by the X code, feeds the pilot gallery independently of load pressure for consistent switching. The integrated 6E pilot control valve meters this pilot flow, and the spool will move once the supply exceeds the minimum pilot pressure of 13 bar. Continuous service is permitted up to 350 bar system pressure, allowing the valve to operate in high-pressure circuits.

Maximum pilot pressure is limited to 250 bar to protect the pilot components from overloading. The valve accepts ambient temperatures from ‑20 °C to +50 °C, so it can be installed in unheated machinery halls or warm engine rooms. Hydraulic fluid may range between ‑20 °C and +80 °C without impairing sealing materials, supporting cold starts and continuous high-temperature service. Electrical connection is provided by a DIN EN 175301-803 plug coded K4, which offers quick disconnect wiring for the solenoid coil. A concealed manual override designated N9 lets maintenance personnel shift the spool locally while keeping external surfaces flush for safety. Mounting uses four M12 × 60 screws of property class 10.9, and these fasteners must be tightened to 100 Nm to maintain sealing against the sub-plate. System cleanliness must reach ISO 4406 class 20/18/15; this filtration level prevents particle-induced wear inside the precision spool lands and pilot orifices.