Four wheel skid control system with dynamic proportioning

Claim 2

In combination with a vehicular braking system having skid control, a dynamic proportioning valve comprising first and second valve elements, said first valve element comprising a differential area piston having separate piston areas on opposite ends thereof and having oppositely disposed enlarged piston areas at an intermediate portion thereof, operator actuated means for supplying static pressure to one of said separate piston areas, whereby a corresponding pressure is delivered by the opposite separate pressure areas to a point of utilization, a vehicle actuated means supplying dynamic pressure to said oppositely disposed enlarged piston areas, said second valve element comprising a spool valve having a pair of axially spaced spool sections allowing when open corresponding cavities adjacent each spool section to freely output through the second valve element to drain so that no pressure registers in such cavities, means communicating each corresponding cavity to said dynamic pressure acting on corresponding of said oppositely disposed enlarged Piston areas, and means for applying a variable pressure signal to opposite ends of said spool valve which is a function of the difference in speed between the front and rear wheels of the vehicle, whereby said spool valve will control the dynamic proportioning of pressure acting on said first valve element with an optimum relationship of front-to-rear wheel slip.

Claim 3

A skid controller for a vehicle having two sets of wheels including front wheels and rear wheels each having their own brake motors and comprising, a means for measuring rear wheel speed, a means for measuring front wheel speed, an external power means for supplying pressure to separate front and rear brake actuating motors, and dynamic pressure control means responsive to differences in front and rear wheel speeds, thereby to apply more or less pressure to the front brake actuating motors to maintain an optimum relationship of front-to-rear wheel slip.

Claim 4

A skid controller for a vehicle having two sets of wheels including front wheels and rear wheels each having their own brake motors and comprising, a means for measuring rear wheel speed, a means for measuring front wheel speed, an external power means for supplying pressure to separate front and rear brake actuating motors, and dynamic pressure control means responsive to differences in front and rear wheel speeds, thereby to apply more or less pressure to the front brake actuating motors to maintain an optimum relationship of front-to-rear wheel slip.

Claim 5

For use in a skid controller, a dynamic proportioning valve comprising first and second valve elements, said first valve element comprising an up-down valve having a differential area piston formed with separate piston areas on opposite ends thereof and having oppositely disposed enlarged piston areas at an intermediate portion thereof, means for supplying master cylinder pressure to one of said separate piston areas, whereby a corresponding pressure may be delivered by the opposite separate pressure area to the front wheels of the vehicle, and means for supplying dynamic pressure from a power source to said oppositely disposed enlarged piston areas, said second valve element comprising a speed control spool valve having a pair of axially spaced spool sections allowing when open corresponding cavities adjacent each respective spool section to freely output through the second valve element to drain so that no pressure registers in the cavities, means communicating each corresponding cavity to said dynamic pressure acting on corresponding of said oppositely disposed enlarged piston areas, means for applying a rear wheel generated pressure signal to one end of said spool valve, and means for applying a front wheel generated pressure signal to the other end of said spool valve, whereby the spool valve will control the dynamic proportioning of pressure acting on the first valve element to maintain an optimum relationship of front-to-rear wheel slip.

Claim 6

For use in a skid controller, a dynamic proportioning valve comprising first and second valve elements, said first valve element comprising an up-down valve having a differential area piston formed with separate piston areas on opposite ends thereof and having oppositely disposed enlarged piston areas at an intermediate portion thereof, means for supplying master cylinder pressure to one of said separate piston areas, whereby a corresponding pressure may be delivered by the opposite separate pressure area to the front wheels of the vehicle, and means for supplying dynamic pressure from a power source to said oppositely disposed enlarged piston areas, said second valve element comprising a speed control spool valve having a pair of axially spaced spool sections allowing when open corresponding cavities adjacent each respective spool section to freely output through the second valve element to drain so that no pressure registers in the cavities, means communicating each corresponding cavity to said dynamic pressure acting on corresponding of said oppositely disposed enlarged piston areas, means for applying a rear wheel generated pressure signal to one end of said spool valve, and means for applying a front wheel generated pressure signal to the other end of said spool valve, whereby the spool valve will control the dynamic proportioning of pressure acting on the first valve element to maintain an optimum relationship of front-to-rear wheel slip.

Claim 9

Dynamic proportioning means for a vehicular braking system with skid control comprising, a differential area piston having a first set of smaller areas for transmitting master cylinder pressure to the front wheel braking means in a 1/1 proportion and having a second set of larger areas for receiving dynamic pressure from a power source to transmit augmented pressure to the front wheel braking means, and a slip control valve comprising a spool having two spool sections for venting dynamic pressure from said second set of larger areas to drain when said two spool sections are open so that no pressure registers on such larger areas, and means for applying signals to opposite ends of said spool which are respectively a function of rear wheel rotation and front wheel rotation so that the net effeCtive signal acting on said spool will dynamically proportion the dynamic pressure acting on said piston to maintain an optimum front-to-rear wheel slip.

Claim 10

Dynamic proportioning means for a vehicular braking system with skid control comprising, a differential area piston having a first set of smaller areas for transmitting master cylinder pressure to the front wheel braking means in a 1/1 proportion and having a second set of larger areas for receiving dynamic pressure from a power source to transmit augmented pressure to the front wheel braking means, and a slip control valve comprising a spool having two spool sections for venting dynamic pressure from said second set of larger areas to drain when said two spool sections are open so that no pressure registers on such larger areas, and means for applying signals to opposite ends of said spool which are respectively a function of rear wheel rotation and front wheel rotation so that the net effeCtive signal acting on said spool will dynamically proportion the dynamic pressure acting on said piston to maintain an optimum front-to-rear wheel slip.

Claim 11

Dynamic proportioning means as defined in claim 5 and further characterized by a preloading spring acting on said differential area piston to exert hold-off pressure on said piston, thereby developing a hold-off function to prevent drag on the front wheel brakes under small residual pressures.

Claim 12

An hydraulic power brake system with skid control comprising, separate front and rear braking motors for a wheeled vehicle, a skid control pump rotational as a function of the rotational speed of the rear wheels, a second pump operable as a power source, a master cylinder booster for actuation by the vehicle operator when braking is desired, a front wheel sensor rotatable as a function of the rotational speed of the front wheels, and a dynamic proportioning means for maintaining a relationship in front-to-rear wheel slip comprising, an up-down valve having a differential area piston formed with a first set of smaller piston areas and a second set of larger piston areas, means for applying master cylinder static pressure to one of said smaller piston areas whereby the other of said smaller piston areas will transmit a corresponding pressure to the front wheel braking motors, means for transmitting pressure from said power source to said larger piston areas, a slip control valve comprising a spool having a pair of spool sections which when open will vent a corresponding one of said larger piston areas to drain so no pressure registers thereon, and means for applying a signal generated by said skid control pump to one end of said spool and for applying a signal generated by said front wheel sensor to the other end of said spool, whereby the net signal operating on said spool will position the spool to raise and lower the dynamic pressure loading of said differential area piston.

Claim 13

An hydraulic power brake system with skid control comprising, separate front and rear braking motors for a wheeled vehicle, a skid control pump rotational as a function of the rotational speed of the rear wheels, a second pump operable as a power source, a master cylinder booster for actuation by the vehicle operator when braking is desired, a front wheel sensor rotatable as a function of the rotational speed of the front wheels, and a dynamic proportioning means for maintaining a relationship in front-to-rear wheel slip comprising, an up-down valve having a differential area piston formed with a first set of smaller piston areas and a second set of larger piston areas, means for applying master cylinder static pressure to one of said smaller piston areas whereby the other of said smaller piston areas will transmit a corresponding pressure to the front wheel braking motors, means for transmitting pressure from said power source to said larger piston areas, a slip control valve comprising a spool having a pair of spool sections which when open will vent a corresponding one of said larger piston areas to drain so no pressure registers thereon, and means for applying a signal generated by said skid control pump to one end of said spool and for applying a signal generated by said front wheel sensor to the other end of said spool, whereby the net signal operating on said spool will position the spool to raise and lower the dynamic pressure loading of said differential area piston.

Claim 14

An hydraulic power braking system with skid control as defined in claim 7 wherein said second pump is the vehicle power steering pump.

Claim 15

A power brake system with skid control comprising, separate front and rear braking motors for a wheeled vehicle, a master cylinder booster for actuation by the vehicle operator when braking is desired, and a dynamic proportioning means for maintaining front-to-rear wheel slip comprising, an up-down valve having a differential area piston with a first set of piston areas in the proportion of 1/1 and a second set of larger piston areas, means for transmitting master cylinder static pressure through the smaller piston areas to the front braking motors, means for transmitting dynamic pressure from a source to the larger piston areas, and a slip control valve for selectively venting either or both of said larger piston areas as a function of valve position, and signal means for applying a net signal to the slip control valve which is derived as the functional relationship of rear wheel rotation and front wheel rotation, thereby to maintain an optimum front-to-rear wheel slip relationship.

Claim 16

A power brake system with skid control comprising, separate front and rear braking motors for a wheeled vehicle, a master cylinder booster for actuation by the vehicle operator when braking is desired, and a dynamic proportioning means for maintaining front-to-rear wheel slip comprising, an up-down valve having a differential area piston with a first set of piston areas in the proportion of 1/1 and a second set of larger piston areas, means for transmitting master cylinder static pressure through the smaller piston areas to the front braking motors, means for transmitting dynamic pressure from a source to the larger piston areas, and a slip control valve for selectively venting either or both of said larger piston areas as a function of valve position, and signal means for applying a net signal to the slip control valve which is derived as the functional relationship of rear wheel rotation and front wheel rotation, thereby to maintain an optimum front-to-rear wheel slip relationship.

Claim 17

For use in a wheeled vehicle skid controller, a dynamic proportioning valve having means for dynamically proportioning pressure to the front and rear braking motors of the wheeled vehicle, operator actuated means for supplying operator generated pressure to said valve, power operated means for supplying dynamically generated pressure to said valve, means for applying a rear wheel generated pressure signal to said valve, and means for applying a front wheel generated signal to said valve, whereby said valve will maintain an optimum relationship of front-to-rear wheel slip.

Claim 18

For use in a wheeled vehicle skid controller, a dynamic proportioning valve having means for dynamically proportioning pressure to the front and rear braking motors of the wheeled vehicle, operator actuated means for supplying operator generated pressure to said valve, power operated means for supplying dynamically generated pressure to said valve, means for applying a rear wheel generated pressure signal to said valve, and means for applying a front wheel generated signal to said valve, whereby said valve will maintain an optimum relationship of front-to-rear wheel slip.