Solenoid operated valve assembly for variable bleed pressure proportional control

摘要

A solenoid operated exhaust bleed type pressure control valve assembly providing a proportional pressure control signal over the full range of solenoid operating current. A poppet valve member is connected to the solenoid armature and closes against a valve seat in the control signal port pressure chamber to prevent flow through the valve seat to the exhaust (bleed) ports. This results in very low or reduced leakage at minimum pressures. The poppet valve contacts a projection on a spool valve for effecting concurrent movement therewith for valving a supply pressure port in the control signal pressure chamber. In the nonnally closed version of the valve assembly, the poppet delays the spool opening of the inlet or supply port until solenoid current has reached about Five to Twenty Percent (5 - 20%) of maximum. In the normally open version, the spool is delayed in closing the supply inlet port until solenoid current reaches about Eighty to One Hundred Percent (80 - 100%) of maximum.