Load responsive brake control valve
AssigneeNippon Air Brake Co., Ltd.
InventorShigeaki Doto
Life of this patent
Estimating the term…
Abstract
A load responsive valve for the braking of vehicles having load supporting air springs. The air spring pressure is employed to regulate the brake pressure through conventional proportioning-type valving. A pilot valve senses the application and release of the vehicle brakes in order to nullify operation of the air spring operated control piston so long as the brake is released, in order to reduce component wear and air consumption due to valve oscillation resulting from air spring pressure variation as the car jounces in service. This is accomplished by pilot pressure supplied via the pilot valve to counteract the air spring pressure acting on the control piston. During a brake application, the pilot valve exhausts this pilot pressure to permit the air spring pressure to operate the control valve in a normal manner.
Claims10
A proportional type load responsive control valve for a vehicle brake system comprising:
- (a) a housing having a supply inlet, at least one control inlet, a pilot inlet, a delivery outlet, and an exhaust outlet;
- (b) valve means having an application position for establishing fluid pressure communication between said supply inlet and said delivery outlet, and a release position for establishing fluid pressure communication between said delivery outlet and said exhaust outlet;
- (c) first piston means subject on one side to a load responsive control fluid pressure corresponding to the vehicle load condition at said at least one control inlet for urging movement of said valve means toward said application position;
- (d) second piston means subject to the fluid pressure effective at said delivery outlet for urging movement of said valve means toward said release position;
- and
- (e) said first piston means being further subject on the opposite side to a pilot pressure at said pilot inlet only when a release condition of vehicle braking exists for counteracting said control fluid pressure at said one side and thereby preventing said movement of said valve means toward said application position.
Dependencies are inferred from the claim text.