Adaptive braking system with hydraulically powered modulator

Claim 2

A vehicle antiskid braking system comprising: wheel means including braking means; said wheel means having a deceleration sensing means; a master cylinder operatively connected to said braking means; a source of pressurized hydraulic fluid; an operator-operated means; a valve means operatively connected to said source of pressurized hydraulic fluid and responsive to operation of said operator-operated means to actuate said master cylinder and energize said braking means; a hydraulic modulator interposed between said master cylinder and said braking means, said hydraulic modulator comprising a housing, a piston means, a check valve means, and a solenoid valve means; and computer means connected to said deceleration sensing means and said solenoid valve means; said piston means movable within said housing and forming therewith a variable volume chamber whose volume is controlled by said piston means which responds to said source of pressurized hydraulic fluid; said check valve means being in series fluid flow between said master cylinder and said braking means via said variable volume chamber and operatively responsive to said piston means within said housing; said computer means automatically responsive to said deceleration sensing means to control said solenoid valve means and thereby position said piston means so as to close said check valve means to allow said braking means to vent hydraulic fluid to said chamber which partially deenergizes said braking means.

Claim 3

The vehicle antiskid braking system, as recited in claim 1, wherein said solenoid valve means includes a first and second solenoid valve, said first solenoid valve reducing pressurized hydraulic fluid in said hydraulic modulator upon receiving a first signal from said computer means and said second solenoid valve providing a fast restoration of said pressurized hydraulic fluid in said hydraulic modulator upon receiving a second signal from said computer means, said second solenoid valve including a bleed means to allow a normal restricted communication of said pressurized hydraulic fluid to said hydraulic modulator.

Claim 4

The vehicle antiskid braking system, as recited in claim 2, wherein said piston means includEs a power piston and a modulation piston, said power piston being responsive to said pressurized hydraulic fluid in said hydraulic modulator to move said modulation piston which operates said check valve means and varies said variable volume chamber.

Claim 5

A vehicle antiskid braking system comprising: wheel means including braking means and deceleration sensing means; a master cylinder operatively connected to said braking means; a source of pressurized hydraulic fluid; an operator-operated means; a first valve means operatively connected to said source of pressurized hydraulic fluid and responsive to operation of said operator-operated means to actuate said master cylinder and energize said braking means; a hydraulic modulator including a second valve means interposed between said master cylinder and said braking means; and computer means connected to said deceleration sensing means and said hydraulic modulator for automatically controlling said second valve means; said hydraulic modulator being connected to said source of pressurized hydraulic fluid to effect control of said second valve means to thereby override the braking action on said braking means by said master cylinder, said hydraulic modulator including: a housing having inlet and outlet ports connected, respectively, to said master cylinder and said braking means; said housing having inlet and outlet control ports connected, respectively, to said source of pressurized hydraulic fluid and a return for said source of pressurized hydraulic fluid, said housing having a stepped bore; a first valve means connected to said inlet control port; a second valve means connected to said outlet control port; a stepped piston means slidably installed in said stepped bore thereby forming first and second control chambers and a slave chamber, said inlet and outlet ports connected to said slave chamber; check valve means carried in said slave chamber so as to be in series flow with said inlet and outlet ports; and resilient means interposed between said housing and said stepped piston means against said check valve means to maintain said check valve means normally open; said first control chamber being responsive to said inlet control port pressure; said second control chamber being responsive to said inlet and outlet control port pressures via said first and second valve means; whereby upon pressurization of said source of pressurizable hydraulic fluid said hydraulic modulator being responsive to a valve control means to close said first valve means and open said second valve means to allow said control chamber to develop a hydraulic fluid pressure differential across said stepped piston means and move it to thereby close said check valve means and enlarge said slave chamber to reduce the pressure of the hydraulic fluid in communication with said braking means.

Claim 6

A vehicle antiskid braking system comprising: wheel means including braking means and deceleration sensing means; a master cylinder operatively connected to said braking means; a source of pressurized hydraulic fluid; an operator-operated means; a first valve means operatively connected to said source of pressurized hydraulic fluid and responsive to operation of said operator-operated means to actuate said master cylinder and energize said braking means; a hydraulic modulator including a second valve means interposed between said master cylinder and said braking means; and computer means connected to said deceleration sensing means and said hydraulic modulator for automatically controlling said second valve means; said hydraulic modulator being connected to said source of pressurized hydraulic fluid to effect control of said second valve means to thereby override the braking action on said braking means by said master cylinder, said hydraulic modulator including: a housing having inlet and outlet ports connected, respectively, to said master cylinder and said braking means; said housing having inlet and outlet control ports connected, respectively, to said source of pressurized hydraulic fluid and a return for said source of pressurized hydraulic fluid, said housing having a stepped bore; a first valve means connected to said inlet control port; a second valve means connected to said outlet control port; a stepped piston means slidably installed in said stepped bore thereby forming first and second control chambers and a slave chamber, said inlet and outlet ports connected to said slave chamber; check valve means carried in said slave chamber so as to be in series flow with said inlet and outlet ports; and resilient means interposed between said housing and said stepped piston means against said check valve means to maintain said check valve means normally open; said first control chamber being responsive to said inlet control port pressure; said second control chamber being responsive to said inlet and outlet control port pressures via said first and second valve means; whereby upon pressurization of said source of pressurizable hydraulic fluid said hydraulic modulator being responsive to a valve control means to close said first valve means and open said second valve means to allow said control chamber to develop a hydraulic fluid pressure differential across said stepped piston means and move it to thereby close said check valve means and enlarge said slave chamber to reduce the pressure of the hydraulic fluid in communication with said braking means.

Claim 7

A hydraulic modulator, as recited in claim 4 wherein said check valve means comprises: a plug member having a stepped passage therethrough and forming a valve seat on one end; a valve member including a stem; a valve guide member installed around said stem and carried in said passage; said valve guide member secured to said valve member by a crimped portion of said stem; resilient means interposed between said plug member and said valve guide member to urge said valve member against said valve seat.

Claim 8

A hydraulic modulator, as recited in claim 4 wherein said first and second valve means each comprise a solenoid valve means.

Claim 9

A hydraulic modulator, as recited in claim 6 wherein said solenoid valve means comprises: a conductive housing; a source of current; coil means suitably secured to said housing and selectively connectable to said source of current; core means suitably positioned within said housing; a nonmagnetic tube member axially and radially positioned by said core means; an armature member slidably carried by said nonmagnetic tube member so as to establish a predetermined radial airgap between said armature and said core means; valve seat means held by said core means and said housing; valve means adjustably carried by said armature member; and resilient means interposed between said core means and said valve means to normally urge said valve means against said valve seat means; said coil means responsive to connection with said source of current to magnetically attract said armature and lift said valve means off said valve seat means.

Claim 10

In a vehicle hydraulic braking system having a wheel to be braked and a mechanism responsive to wheel rotation for establishing a control signal which reflects wheel acceleration, a pressure modulating device comprising a housing with a bore therein having piston means forming a first chamber which is in series flow relationship with said hydraulic braking system, first valve means operatively connected in said braking system for controlling pressure within said first chamber, said first valve means being operatively connected to said piston means, said piston means also forming a second chamber within said bore in continuous communication with a pressurized hydraulic fluid, and a third chamber in communication with an outlet control port, a second valve means operatively connected between said pressurized hydraulic fluid and said third chamber and responsive to a first predetermined wheel characteristic rotation established in said mechanism for controlling communication between said third chamber and said pressurized hydraulic fluid, and a third valve means operatively connected between said third chamber and said outlet port and responsive to a second predetermined wheel characteristic rotation established in said mechanism to thereby cause said piston means to effect control of said first valve means.

Claim 11

In a vehicle hydraulic braking system having a wheel to be braked and a mechanism responsive to wheel rotation for establishing a control signal which reflects wheel acceleration, a pressure modulating device comprising a housing with a bore therein having piston means forming a first chamber which is in series flow relationship with said hydraulic braking system, first valve means operatively connected in said braking system for controlling pressure within said first chamber, said first valve means being operatively connected to said piston means, said piston means also forming a second chamber within said bore in continuous communication with a pressurized hydraulic fluid, and a third chamber in communication with an outlet control port, a second valve means operatively connected between said pressurized hydraulic fluid and said third chamber and responsive to a first predetermined wheel characteristic rotation established in said mechanism for controlling communication between said third chamber and said pressurized hydraulic fluid, and a third valve means operatively connected between said third chamber and said outlet port and responsive to a second predetermined wheel characteristic rotation established in said mechanism to thereby cause said piston means to effect control of said first valve means.

Claim 12

The vehicle hydraulic braking system, as recited in claim 8, wherein said piston means includes a power piston and a modulating piston, said power piston moving said modulating piston to operate said first valve means and vary braking force applied to said wheel by said hydraulic braking system.

Claim 13

The vehicle hydraulic braking system, as recited in claim 9 wherein said second and third valve means are solenoid valves that control pressure in said third chamber, said braking force being decreased as pressure in said third chamber is decreased.