High force solenoid and solenoid-driven actuator

摘要

A solenoid having increased axial force and low static friction on the armature is disclosed and provides an improved solenoid-driven hydraulic valve actuator. The solenoid includes a coil member, a pole piece having an inside surface with recessed and non-recessed portions to form an inner recess in the pole piece, an armature inside the pole piece, and a bearing held in the recess between the pole piece and armature, the bearing having an inner surface extending inwardly just beyond the inside surface of the pole piece non-recessed portion.