US3874742A — Hydraulic brake pressure control system

Claim 1

Independent Claim 327 words

A hydraulic brake pressure control system for a vehicle having a brake pedal, a source of pressurized fluid and an electric circuit for delivering an output signal indicative of an optimum brake control operation comprising: a housing having a bore and inlet, outlet and drain ports, said inlet ports being connected to said source of pressurized fluid, a spool valve slidably mounted within said bore of said housing for controlling hydraulic communication between said inlet, outlet and drain ports, a push rod associated with said brake pedal and associated mechanically with said spool valve for actuating the latter, a reaction member providing a return force for urging said spool valve in its original position against a pedal depressing force acting on said push rod, said reaction member having one end which is exposed to an output pressure in said outlet port, a pair of hydraulic pressure chambers opposedly formed at both ends of said spool valve and in fluid communication with said source of pressurized fluid through conduit means, said conduit means comprising a first conduit communicating with one of said hydraulic pressure chambers and a second conduit communicating with the other of said hydraulic pressure chambers, each of said first and second conduits having an orifice through which said pressurized fluid may be supplied to said hydraulic pressure chambers, and an actuator electrically connected to said electric circuit for controlling the hydraulic pressure in at least one of said chambers in accordance with said indicating signal whereby said hydraulic pressure in said one chamber will assist said spool valve to move to increase the hydraulic pressure at said outlet port when the hydraulic pressure in said one chamber is greater than that in said other chamber, and the hydraulic pressure in said other chamber will assist said spool valve to move to decrease the hydraulic pressure at said outlet port when the hydraulic pressure in said other chamber is greater than that in said one chamber.

Claim 2

Dependent Claim 327 words

A hydraulic brake pressure control system for a vehicle having a brake pedal, a source of pressurized fluid and an electric circuit for delivering an output signal indicative of an optimum brake control operation comprising: a housing having a bore and inlet, outlet and drain ports, said inlet ports being connected to said source of pressurized fluid, a spool valve slidably mounted within said bore of said housing for controlling hydraulic communication between said inlet, outlet and drain ports, a push rod associated with said brake pedal and associated mechanically with said spool valve for actuating the latter, a reaction member providing a return force for urging said spool valve in its original position against a pedal depressing force acting on said push rod, said reaction member having one end which is exposed to an output pressure in said outlet port, a pair of hydraulic pressure chambers opposedly formed at both ends of said spool valve and in fluid communication with said source of pressurized fluid through conduit means, said conduit means comprising a first conduit communicating with one of said hydraulic pressure chambers and a second conduit communicating with the other of said hydraulic pressure chambers, each of said first and second conduits having an orifice through which said pressurized fluid may be supplied to said hydraulic pressure chambers, and an actuator electrically connected to said electric circuit for controlling the hydraulic pressure in at least one of said chambers in accordance with said indicating signal whereby said hydraulic pressure in said one chamber will assist said spool valve to move to increase the hydraulic pressure at said outlet port when the hydraulic pressure in said one chamber is greater than that in said other chamber, and the hydraulic pressure in said other chamber will assist said spool valve to move to decrease the hydraulic pressure at said outlet port when the hydraulic pressure in said other chamber is greater than that in said one chamber.

Claim 3

Dependent Claim 25 words

A hydraulic brake pressure control system as set forth in claim 1, wherein said push rod and said spool valve are formed as a unit.

Claim 4

Dependent Claim 56 words

A hydraulic brake pressure control system as set forth in claim 1, wherein said pair of chambers are hydraulically connected to said source of pressurized fluid, and both effective diameters of said chambers are equal to each other, and said reaction member having an effective cross-sectional area which is equal to that of said push rod.

Claim 5

Dependent Claim 32 words

A hydrualic brake pressure control system as set forth in claim 3, wherein said actuator comprises a flapper valve which controls the dischargingresistance of the fluid flow out of said pressure chamber.

Claim 6

Dependent Claim 46 words

A hydraulic brake pressure control system as set forth in claim 1, wherein said one end of said reaction member is adapted so as to expand into a bore of said spool valve to thereby define a hydraulic chamber which is communicated with said outlet port.

Claim 7

Dependent Claim 303 words

A hydraulic brake pressure control system for a vehicle having a brake pedal, comprising: a first source of pressurized fluid, a control valve assembly communicated with said first source of pressurized fluid through a first passage, a second source of pressurized fluid connected to said first source of pressurized fluid through a second passage, and connected to said control valve assembly through a third passage, a change-over valve assembly disposed within said first, second and third passages and having a first position in which said first passage is opened and a second position in which said second and third passages are opened, said control valve assembly comprising a housing having a bore, said housing being formed with inlet, outlet and drain ports, said inlet port being connected to said third passage and said outlet port being adapted to be connected to said first passage through a check valve, a spool valve slidably mounted within said bore of said housing for controlling hydraulic communication between said inlet, outlet and drain ports, a push rod associated with said brake pedal and associated mechanically with said spool valve for actuating the latter, a reaction member providing a return force for urging said spool valve in its original position against a pedal depressing force acting on said spool valve, said reaction member having one end which is exposed to an outlet pressure in said outlet port and having an effective cross-sectional area which is equal to that of said push rod, and a pair of hydraulic pressure chambers opposedly formed at both ends of said spool valve, an electric circuit delivering an output signal indicating an optimum brake control operation, and an actuator electrically connected to said electric circuit for controlling the hydraulic pressure in at least one of said chambers in accordance with said indicating signal.

Claim 8

Dependent Claim 303 words

A hydraulic brake pressure control system for a vehicle having a brake pedal, comprising: a first source of pressurized fluid, a control valve assembly communicated with said first source of pressurized fluid through a first passage, a second source of pressurized fluid connected to said first source of pressurized fluid through a second passage, and connected to said control valve assembly through a third passage, a change-over valve assembly disposed within said first, second and third passages and having a first position in which said first passage is opened and a second position in which said second and third passages are opened, said control valve assembly comprising a housing having a bore, said housing being formed with inlet, outlet and drain ports, said inlet port being connected to said third passage and said outlet port being adapted to be connected to said first passage through a check valve, a spool valve slidably mounted within said bore of said housing for controlling hydraulic communication between said inlet, outlet and drain ports, a push rod associated with said brake pedal and associated mechanically with said spool valve for actuating the latter, a reaction member providing a return force for urging said spool valve in its original position against a pedal depressing force acting on said spool valve, said reaction member having one end which is exposed to an outlet pressure in said outlet port and having an effective cross-sectional area which is equal to that of said push rod, and a pair of hydraulic pressure chambers opposedly formed at both ends of said spool valve, an electric circuit delivering an output signal indicating an optimum brake control operation, and an actuator electrically connected to said electric circuit for controlling the hydraulic pressure in at least one of said chambers in accordance with said indicating signal.

Claim 9

Dependent Claim 35 words

A hydraulic brake pressure control system as set forth in claim 6, wherein said first source of pressurized fluid comprises a hydraulic pump and said second sOurce of pressurized fluid comprises at least one accumulator.

Claim 10

Dependent Claim 25 words

A hydraulic brake pressure control system as set forth in claim 7, wherein said spool valve and said push rod are formed as a unit.

Claim 11

Dependent Claim 57 words

A hydraulic brake pressure control system as set forth in claim 7, wherein said pair of chambers are hydraulically connected to said third passage and the discharging-resistance of the fluid flow out of said chambers will be controlled by a flapper valve of said actuator, and both effective diameters of said chambers are equal to each other.

Claim 12

Dependent Claim 34 words

A hydraulic brake pressure control system as set forth in claim 7, further comprising means for actuating said change-over valve assembly into said first position when a predetermined pressure is stored in said accumulator.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1978-03-31	1978-09-30	1979-04-01	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1982-03-31	1982-09-30	1983-04-01	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1986-03-31	1986-09-30	1987-04-01	$7700.00	Window Closed / Lapsed

Hydraulic brake pressure control system

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