Pressure control valve

Claim 2

In a fluid pressure control system for a vehicle including pressure control valve means disposed between a source of fluid pressure and fluid pressure actuating means, said control valve means comprising: a housing having a bore therein and a single inlet port, a single outlet port and a single drain port, all directly opening into said bore; a valve spool slidably mounted within said bore of said housing for controlling fluid communication between said inlet and outlet ports and between said outlet and drain ports, said valve spool defining first and second chambers within said housing; a first passage means within said housing for supplying said fluid pressure conveyed to said inlet port to said first chamber so as to urge said valve spool in one direction; a first orifice provided within said first passage means; a second passage means within said housing leadiNg from said first chamber to said outlet port and having a second orifice therein; a third passage means within said housing for supplying said fluid pressure conveyed to said inlet port to said second chamber so as to urge said valve spool in another direction; a third orifice disposed within said third passage means; a second bore in said housing having a drain port; a flapper valve means disposed in said second bore of said housing adapted to be actuated by an output signal responsive to a vehicle operation condition; and a nozzle in said housing leading from said second chamber being directly open into said second bore and cooperating with said flapper valve means so as to act as a variable orifice to thereby drain said fluid pressure within said second chamber to said second bore.

Claim 3

In a fluid pressure control system for a vehicle including pressure control valve means disposed between a source of fluid pressure and fluid pressure actuating means, said control valve means comprising: a housing having associated therewith an inlet port, an outlet port and a drain port; a valve spool slidably mounted within said housing for controlling fluid communication between said inlet and outlet ports and between said outlet and drain ports, said valve spool defining first and second chambers within said housing; a first passage means for supplying said fluid pressure conveyed to said inlet port to said first chamber so as to urge said valve spool in one direction; a first orifice provided within said first passage means; a second passage means leading from said first chamber to said outlet port and having a second orifice therein; a third passage means for supplying said fluid pressure conveyed to said inlet port to said second chamber so as to urge said valve spool in another direction; a third orifice disposed within said third passage means; a flapper valve means adapted to be actuated by an output signal responsive to a vehicle operation condition; and a nozzle cooperating with said flapper valve means so as to act as a variable orifice to thereby drain said fluid pressure within said second chamber, wherein said valve spool comprises a first annular groove hydraulically connected to said inlet port and a second annular groove hydraulically connected to said drain port, and said housing comprises another annular groove hydraulically connected to said outlet port cooperating with said first and second grooves of said valve spool depending upon the sliding movement of said valve spool.

Claim 4

In a fluid pressure control system for a vehicle including pressure control valve means disposed between a source of fluid pressure and fluid pressure actuating means, said control valve means comprising: a housing having associated therewith an inlet port, an outlet port and a drain port; a valve spool slidably mounted within said housing for controlling fluid communication between said inlet and outlet ports and between said outlet and drain ports, said valve spool defining first and second chambers within said housing; a first passage means for supplying said fluid pressure conveyed to said inlet port to said first chamber so as to urge said valve spool in one direction; a first orifice provided within said first passage means; a second passage means leading from said first chamber to said outlet port and having a second orifice therein; a third passage means for supplying said fluid pressure conveyed to said inlet port to said second chamber so as to urge said valve spool in another direction; a third orifice disposed within said third passage means; a flapper valve means adapted to be actuated by an output signal responsive to a vehicle operation condition; and a nozzle cooperating with said flapper valve means so as to act as a variable orifice to thereby drain said fluid pressure within said second chamber, wherein said valve spool comprises a first annular groove hydraulically connected to said inlet port and a second annular groove hydraulically connected to said drain port, and said housing comprises another annular groove hydraulically connected to said outlet port cooperating with said first and second grooves of said valve spool depending upon the sliding movement of said valve spool.

Claim 5

The system as set forth in claim 2, wherein said first and third passage means are respectively provided within said valve spool and said first and third orifices are respectively formed within orifice members which are respectively provided within said valve spool.

Claim 6

The system as set forth in claim 2, wherein said second passage means is formed within said housing.

Claim 7

The system as set forth in claim 1, wherein said flapper valve means is moved in proportion to said output signal whereby the size of the opening of said nozzle is determined in proportion to said output signal.