PROPORTIONAL VARIABLE FORCE SOLENOID CONTROL VALVE WITH SEGMENTED PERMANENT MAGNET

摘要

A proportional variable force solenoid fluid control valve for controlling the pressure of a pressurized fluid in a fluid control system in proportion to the current level of an electrical input signal includes an armature in engagement with a fluid pressure control valve and movable in response to electrical current applied to a solenoid disposed on a coil bobbin in a solenoid housing and a coil spring for biasing the armature in a direction to establish a valve fluid pressure response to current level supplied to the solenoid. A plurality of axially magnetized permanent magnet segments each having an inner arcuate magnet surface facing the armature are provided to collectively provide a permanent magnetic field that cooperates with the electromagnetic field of the energized coil to move the armature. The permanent magnet segments are disposed in a circular array about the periphery of the armature in respective circumferentially spaced apart, axially extending pockets of the coil bobbin in a common transverse plane relative to the longitudinal axis of movement of the armature. The magnet segments are selected in number and arcuate surface extent to collectively encompass or overlie less than 100% of the peripheral surface of the armature when viewed in cross-section transverse to the longitudinal axis.