a solenoid operated valve has a valve body with a plurality of ports and a spool slidable within the valve body to interconnect the ports in different combinations . an actuator drives the spool into several operating positions . the actuator has a solenoid assembly with an aperture within which first and second tubular pole pieces are received . an armature is able to slide within the two pole pieces and a push member projects from the armature abutting the spool . the push member is secured to a rolling bearing which has a plurality of rolling elements that roll against the pole pieces to reduce resistance to movement of the armature .