Electrically controlled pressure-holding valve

摘要

A pressure-holding valve for a brake system having a body with a blind bore therein. The body has a first passage which connects the blind bore with a variable pressure inlet port and a pressure outlet port. The blind bore is closed by seals carried on a plug having an axial passage therein connecting said inlet port with a second passage connected to the first passage. A non-return valve is located in said blind bore between the plug and the bottom of the blind bore while a valve controlled by an electromagnet is locate in the plug. In response to an operational signal the valve controlled by the electromagnet is moved into engagement with a seat to interrupt communication between the inlet port and the first passage. If the pressure holding valve is on an incline plane, the non-return valve moves to close the axial passage to prevent the return of pressurised fluid from the outlet port toward the inlet port and thereby maintain the fluid pressure in the system at a value of the fluid pressure at the outlet port to sustain a brake application.