SOLENOID OPERATED VALVE ASSEMBLY FOR VARIABLE BLEED PRESSURE PROPORTIONAL CONTROL

摘要

A solenoid operated exhaust bleed type pressure controlvalve assembly providing a proportional pressure controlsignal over the full range of solenoid operating current. Apoppet valve member is connected to the solenoid armature andcloses against a valve seat in the control signal portpressure chamber to prevent flow through the valve seat to theexhaust (bleed) ports. This results in very low or reducedleakage at minimum pressures. The poppet valve contacts aprojection on a spool valve for effecting concurrent movementtherewith for valving a supply pressure port in the controlsignal pressure chamber. In the normally closed version ofthe valve assembly, the poppet delays the spool opening of theinlet or supply port until solenoid current has reached aboutFive to Twenty Percent (5 - 20%) of maximum. In the normallyopen version, the spool is delayed in closing the supply inletport until solenoid current reaches about Eighty to OneHundred Percent (80 - 100%) of maximum.