Proportional variable bleed solenoid valve with single adjustment pressure calibration and including poppet valve seal ball

摘要

A proportional variable bleed solenoid valve that includes magnetic force adjustments to provide magnetic calibration. The control valve includes a housing defining a chamber, where an electromagnetic coil is wound on a bobbin and is coaxially mounted within the housing. A movable armature is coaxially positioned within the bobbin in the chamber and has an armature poppet valve extending form a bottom end of the armature. An armature spring is in contact with an upper end of the armature and a top wall of the bobbin, where the spring positions the armature in an initial position when the coil is not energized and where the armature moves to a second position in conjunction with the bias of the armature spring when the coil is energized. A pole piece is mounted to the housing and is positioned adjacent to the lower end of the armature to define an air gap between the pole piece and the armature. The pole piece includes an extended annular ring positioned below the lower end of the armature such that the armature poppet valve extends through the ring. A mounting bracket is secured to the housing adjacent to the pole piece and a valve sleeve is connected to the mounting bracket. The valve sleeve includes a central bore axially aligned with the armature, where the central bore includes a widened portion proximate the armature poppet valve that defines a shoulder. A control ball is positioned within the widened portion and is positioned against a bottom seal surface of the armature poppet valve and a valve seat surface of the shoulder when the coil is energized to seal off an exhaust port, so that a supply pressure orifice connected to the valve sleeve provides a control pressure at a control pressure opening in the valve sleeve. In order to provide magnetic force adjustments for magnetic calibrations, the valve sleeve is selectively positionable relative to the bracket so that the distance between the armature poppet valve and the seat surface is adjustable. In one particular embodiment, the valve sleeve is secured to the bracket by a threaded connection so that its position can be readily changed.