Vehicle brake system

Claim 2

In a vehicle having a left front wheel and a right front wheel and a pair of rear wheels and brakes for each of said wheels, a vehicle wheel braking system comprising: a master cylinder having three pressurizing chambers and means for pressurizing brake fluid therein; a first conduit connecting a first one of said chambers to said left front wheel brake and having a first brake pressure metering valve therein fluidly intermediate said master cylinder and said left front wheel brake; a second conduit connecting a second one of said chambers to said right front wheel brake and having a second brake pressure metering valve therein fluidly intermediate said master cylinder and said right front wheel brake; a third conduit connecting the third one of said chambers to said pair of rear wheel brakes and having a brake pressure proportioning valve and a wheel lock control pressure modulator therein fluidly intermediate said master cylinder and said pair of rear wheel brakes; and modulator control means for controlling said modulator to control the rear brake apply pressure to prevent excessive rear wheel slip and rear wheel lock.

Claim 3

The vehicle wheel braking system of claim 1 further comprising: warning switch means connected with each of said conduits fluidly adjacent said master cylinder and actuable upon pressure decrease in at least one of said conduits to a predetermined pressure differential in relation to the pressure in at least one other of said conduits to energize a warning device.

Claim 4

In a vehicle having a left front wheel and a right front wheel and a pair of rear wheels and brakes for each of said wheels, a vehicle wheel braking system comprising: a brake master cylinder having three pressurizing chambers and means for selectively pressurizing brake fluid therein; a first brake fluid conduit fluidly connecting a first one of said chambers to said left front wheel brake; a second brake fluid conduit fluidly connecting a second one of said chambers to said right front wheel brake; a third brake fluid conduit fluidly connecting the third one of said chambers to said pair of rear wheel brakes and having a brake pressure proportioning valve and a wheel lock control rear brake pressure modulator therein fluidly intermediate said third one of said chambers and said rear wheel brakes; and rear brake pressure modulator control means for controlling said modulator to modulate rear wheel brake pressure in accordance with sensed rear wheel slip.

Claim 5

In a vehicle having a left front wheel and a right front wheel and a pair of rear wheels and brakes for each of said wheels, a vehicle wheel braking system comprising: a brake master cylinder having three pressurizing chambers and means for selectively pressurizing brake fluid therein; a first brake fluid conduit fluidly connecting a first one of said chambers to said left front wheel brake; a second brake fluid conduit fluidly connecting a second one of said chambers to said right front wheel brake; a third brake fluid conduit fluidly connecting the third one of said chambers to said pair of rear wheel brakes and having a brake pressure proportioning valve and a wheel lock control rear brake pressure modulator therein fluidly intermediate said third one of said chambers and said rear wheel brakes; and rear brake pressure modulator control means for controlling said modulator to modulate rear wheel brake pressure in accordance with sensed rear wheel slip.

Claim 6

The vehicle wheel braking system of claim 3 further comprising: warning switch means connected with each of said conduits fluidly adjacent said master cylinder and actuable upon pressure decrease in at least one of said conduits to a predetermined pressure differential in relation to the pressure in at least one other of said conduits to energize a warning deVice.

Claim 7

In a vehicle having left and right front and rear wheels and hydraulic fluid pressure actuated brakes for each of said wheels, a vehicle wheel braking system comprising: a brake master cylinder having three pressurizing chambers and means for pressurizing brake fluid therein; a first conduit connecting a first one of said chambers to said left front wheel brake and having a first brake pressure metering valve therein fluidly intermediate said master cylinder and said left front wheel brake; a second conduit connecting a second one of said chambers to said right front wheel brake and having a second brake pressure metering valve therein fluidly intermediate said master cylinder and said right front wheel brake; a third conduit connecting the third one of said chambers to said left and right rear wheel brakes and having a wheel lock control rear brake pressure modulator therein fluidly intermediate said third one of said chambers and said rear wheel brakes; and rear brake apply pressure modulator control means and rear wheel slip sensing means for controlling said modulator to modulate rear wheel brake apply pressure in accordance with sensed rear wheel slip.

Claim 8

In a vehicle having left and right front and rear wheels and hydraulic fluid pressure actuated brakes for each of said wheels, a vehicle wheel braking system comprising: a brake master cylinder having three pressurizing chambers and means for pressurizing brake fluid therein; a first conduit connecting a first one of said chambers to said left front wheel brake and having a first brake pressure metering valve therein fluidly intermediate said master cylinder and said left front wheel brake; a second conduit connecting a second one of said chambers to said right front wheel brake and having a second brake pressure metering valve therein fluidly intermediate said master cylinder and said right front wheel brake; a third conduit connecting the third one of said chambers to said left and right rear wheel brakes and having a wheel lock control rear brake pressure modulator therein fluidly intermediate said third one of said chambers and said rear wheel brakes; and rear brake apply pressure modulator control means and rear wheel slip sensing means for controlling said modulator to modulate rear wheel brake apply pressure in accordance with sensed rear wheel slip.

Claim 9

The vehicle wheel braking system of claim 5 further comprising: warning switch means connected with each of said conduits fluidly adjacent said master cylinder and actuable upon pressure decrease in at least one of said conduits to a predetermined pressure differential in relation to the pressure in at least one other of said conduits to energize a warning device.

Claim 10

In a vehicle having left and right wheels arranged as pairs of front and rear wheels and fluid pressure actuated brakes for said wheels, a vehicle wheel braking system comprising: a source of brake supply pressures supplying pressurized fluid from three separate pressure chambers when actuated; first and second independent brake fluid supply pressure conduit means respectively fluid pressure connecting first and second ones of said pressure chambers to said left and right front wheel brakes to supply brake apply pressures thereto; third independent brake fluid conduit means fluid pressure connecting the third one of said pressure chambers to said pair of rear wheel brakes to supply brake apply pressures thereto and having rear wheel brake apply pressure modifying means therein; and control means for said rear wheel brake apply pressure modifying means actuable in response to sensed rear wheel slip to modify rear wheel brake apply pressures and thereby lessen the occurrence of rear wheel lock.

Claim 11

In a vehicle having left and right wheels arranged as pairs of front and rear wheels and fluid pressure actuated brakes for said wheels, a vehicle wheel braking system comprising: a source of brake supply pressures supplying pressurized fluid from three separate pressure chambers when actuated; first and second independent brake fluid supply pressure conduit means respectively fluid pressure connecting first and second ones of said pressure chambers to said left and right front wheel brakes to supply brake apply pressures thereto; third independent brake fluid conduit means fluid pressure connecting the third one of said pressure chambers to said pair of rear wheel brakes to supply brake apply pressures thereto and having rear wheel brake apply pressure modifying means therein; and control means for said rear wheel brake apply pressure modifying means actuable in response to sensed rear wheel slip to modify rear wheel brake apply pressures and thereby lessen the occurrence of rear wheel lock.

Claim 12

The vehicle wheel braking system of claim 7, the brakes of at least one of said pairs of wheels being disc brakes and the conduit means associated therewith having valve means therein modifying the brake supply pressures therein from said source in a predetermined pressure relation to the brake supply pressures normally simultaneously provided in the other conduit means for the other pair of wheel brakes.

Claim 13

The wheel braking system of claim 8, said front wheel brakes being disc brakes and said rear wheel brakes being drum brakes and said valve means including a metering valve in each of said first and second conduit means.

Claim 14

The wheel braking system of claim 8, said rear wheel brakes being disc brakes and said valve means including a proportioning valve in said third conduit means positioned fluidly intermediate said third one of said pressure chambers and said rear wheel brake apply pressure modifying means.