Variable load valve device
AssigneeNippon Air Brake Co., Ltd.
InventorsMinoru Nagase, Shigeaki Doto
Life of this patent
Estimating the term…
Abstract
A vehicle load responsive control valve device in which the output pressure regulating valve assembly is controlled by multiple diaphragm pistons, which are arranged separately in tandem relationship and are operative responsive to the fluid pressure of different air springs of the vehicle. Being of equal pressure areas, these diaphragm pistons are effective to exert a control force on the valve assembly according to the higher of the respective air spring pressures to ensure against low brake forces when the pressure of one of the air springs is inadvertently lost under loaded car conditions. Under empty car conditions, a bias spring is effective to obtain a predetermined output pressure.
Claims7
For a vehicle having air springs to support the vehicle load, there is provided a load responsive valve device having input, output and exhaust ports, said load responsive valve device comprising:
- (a) valve means for establishing fluid pressure communication between said input and output ports in a first position and between said output and exhaust ports in a second position, and for terminating said fluid pressure communications in an intermediate position between said first and second positions;
- (b) a first piston abutment subject to fluid pressure of at least one of said air springs representative of the vehicle load;
- (c) means for transmitting the fluid pressure force exerted by said first piston abutment to said valve means to urge movement thereof toward said first position;
- (d) a second piston abutment subject to fluid pressure effective at said output port for urging said valve means toward said second position in opposition to said fluid pressure force exerted by said first piston abutment, said valve means assuming said intermediate position when the pressure at said output port corresponds to the vehicle load condition;
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- (e) said first piston abutment comprising at least two pistons having equal effective pressure areas arranged separately in tandem relationship, adjacent sides of said at least two pistons being subject to the fluid pressure of a first one of said air springs and the side opposite said adjacent side of one of said at least two pistons being subject to the fluid pressure of a second one of said air springs, so that the higher fluid pressure of said first and second air springs is effective to establish the fluid pressure at said output port in accordance with the vehicle load condition.
For a vehicle having air springs to support the vehicle load, there is provided a load responsive valve device having input, output and exhaust ports, said load responsive valve device comprising:
- (a) valve means for establishing fluid pressure communication between said input and output ports in a first position and between said output and exhaust ports in a second position, and for terminating said fluid pressure communications in an intermediate position between said first and second positions;
- (b) a first piston abutment subject to a control fluid pressure;
- (c) force amplification means for connecting said first piston abutment to said valve means;
- (d) a second piston abutment subject to fluid pressure at said output port for urging said valve means toward said second piston in opposition to said fluid pressure force exerted by said first piston abutment via said force amplification means, said valve means assuming said intermediate position when the pressure at said output port corresponds to said control fluid pressure;
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- (e) a third piston abutment subject to fluid pressure of at least one of said air springs and connected to said force amplification means to adjust the pressure at said output port in accordance with the vehicle load condition, said third piston abutment comprising at least two pistons having equal effective pressure areas arranged separately in tandem relationship, adjacent sides of said at least two pistons being subject to the fluid pressure of a first one of said air springs and the side opposite said adjacent side of one of said at least two pistons being subject to the fluid pressure of a second one of said air springs, so that the higher fluid pressure of said first and second air springs is effective to establish the vehicle load adjusted fluid pressure at said output port.
Dependencies are inferred from the claim text.