Abstract: A proportional pressure control solenoid valve includes a valve spool with dual feedback pins slidable relative to the spool within a common bore of the spool as the spool moves. The feedback pins have unequal cross sectional areas defining an operative feedback area and enabling minimization of the valve's size in a cost efficient manner. To control output pressure as a function of control current, an electro-magnetically generated force initiates modulation of the valve with assistance from a hydraulic feedback force and in opposition to the force of modulating spring.

Abstract: A hydraulic solenoid control valve has the capability of operating at high pulse width modulation frequencies due to precision alignment of the armature and freedom from contamination. An alignment tube coupled at one end to one pole piece aligns coaxially with the armature while a non-magnetic bearing coupled to the other end of the alignment tube also aligns coaxially with the armature. Fluid infusion into the armature cavity is prevented by way of the alignment tube which surrounds the armature.