| 摘要 |
A brake system is disclosed which comprises a primary fluid power brake subsystem and a secondary or back-up brake subsystem. The primary brake system is of the "power brake" type, and includes a power brake valve having a housing defining an elongate bore. A bi-ended rod extends through the housing end wall to be slid between spaced apart first, second and third positions. That end of the rod which is inside the housing is affixed to a reaction piston. The reaction piston cooperates with an annular piston, also carried within the bore, to have fluid flow through the valve and raise fluid pressure within a collapsible chamber defined by the bore. When the rod is partially pulled out of the valve housing, this high pressure fluid is directed to vehicle brakes to cause primary braking action. Should the primary system fail in some respect, rod pull-out action operates to energize a secondary or back-up brake system. Secondary brake system energization is caused by a brake controller which is connected to the primary valve rod, and which is also positioned to engage a secondary brake subsystem master cylinder actuator.
|
