Abstract: A brake system including a master cylinder for generating pressurized fluid, a wheel brake in fluid communication with the master cylinder, and a first valve for regulating the flow of fluid between the master cylinder and the wheel brake. The brake system further includes a pedal travel simulator including a housing having a bore formed therein. A piston is slidably disposed in the bore. The piston and the housing generally defining a fluid chamber which is in fluid communication with the master cylinder. The pedal travel simulator further includes a spring which biases the piston in a direction so as to contract the fluid chamber. The brake system further includes a source of pressurized fluid and a boost valve which is in fluid communication with the source of pressurized fluid and the wheel brake.

Abstract: A vehicular anti-lock and traction control braking system includes a master cylinder. A driven wheel brake is connected to the master cylinder via a first brake conduit. A non-driven wheel brake is connected to the master cylinder via a second brake conduit. A fluid supply is connected to an input of a pump. An output of the pump provides pressurized fluid to the driven and non-driven wheel brakes. A pump supply valve is disposed between the pump inlet and the fluid supply. A driven wheel isolation valve is disposed in the first brake conduit between the driven wheel brake and the master cylinder. The driven wheel isolation valve is opened to allow fluid communication between driven wheel brake and the master cylinder and closed to prevent fluid communication therebetween. A non-driven wheel isolation valve is disposed in the second brake conduit between the non-driven wheel brake and the master cylinder.

Abstract: A slaved dump valve for an anti-lock brake system having two driven rear wheels and traction control includes a check valve and restrictor. In particular the dump valve includes a 2-way/2-position solenoid valve connected to the return conduit of each rear wheel brake cylinder for reducing the pressure at both of the wheel brake cylinders simultaneously. Each return conduit of each rear wheel brake cylinder connected to the slave dump valve contains a check valve oriented to prevent pressurized fluid from flowing from one rear wheel brake cylinder to the other. A restrictor is positioned in each return conduit to allow the pressure at each of the rear wheel brake cylinders to be reduced immediately when the dump valve is opened. Fully independent pressure regulation of the rear wheel brake cylinders connected to the single dump valve can be simulated by controlling inlet valves in conjunction with the single dump valve.

Abstract: A ball screw pump assembly includes a pump body having an axial bore defining a travel chamber and a pressure chamber. An input port and an output port are formed in the pressure chamber. A ball screw is provided in the travel chamber. A piston is connected to the ball screw and slidably extends into the pressure chamber as the ball screw is rotated. The piston divides the pressure chamber into an input chamber having a maximum volume and an output chamber having a maximum volume which is less than the maximum of the input chamber. The ball screw pump assembly can be used in a vehicular braking system.

Abstract: An integrated vehicular braking system which can provide ABS/TC/VSC control using a common auxiliary high pressure source for two circuits includes a separate boost valve pilot operated to control the flow from the high pressure source to provide brake boost. The boost valve is also actuated by a single solenoid to provide the fluid pressures necessary for full ABS/TC/VSC control. The boost valve is removed from a master cylinder/booster assembly, thereby minimizing pressure drops across the dynamic seals, and is not mechanically coupled to the booster or brake pedal. The boost valve is pressure balanced, thereby requiring reduced forces to operate the valve while providing improved brake pedal feel.

Abstract: A vehicular anti-lock brake system utilizes a follow valve (also known as a copy valve) in place of a conventional solenoid valve. The follow valve causes brake fluid pressure for a wheel brake to follow and imitate the brake fluid pressure of a wheel brake controlled by a solenoid valve. The follow valve exclusively regulates fluid pressure at a wheel brake so that fluid pressure is substantially similar to fluid pressure at a wheel brake controlled by a solenoid valve.

Abstract: A supply valve for use in a vehicular braking system includes a housing. A sleeve is disposed within a bore in the housing. A piston is slidably disposed within the bore. A valve element is disposed within the sleeve and includes a valve seat and check element for sealing against the valve seat to close the valve element. A lip seal is disposed on the sleeve for allowing fluid to flow from a low pressure accumulator to a pump, but not in the opposite direction. The supply valve is particularly adapted for use in an anti-lock braking system equipped with traction control.

Abstract: An improved electro-hydraulic brake system having features for improving the pedal feel of the system, while further having design features which contribute to the economy of manufacture of certain components of the system. The system provides for an electrically powered normal source of pressurized hydraulic brake fluid, and a manually powered backup source of pressurized hydraulic brake fluid to the vehicle brakes in the event of failure of the normal source. During normal braking, fluid from the backup source is redirected from the vehicle brakes to a pedal simulator. The pedal simulator preferably includes arrangements of spring loaded pistons, expansion volumes, and damping orifices, together with valves selectively controlling the flow of fluid to and from the pedal simulator which provides for an improved pedal feel during vehicle braking.

Abstract: A hydraulic braking system providing anti-lock braking ("ABS") and traction control ("TC") incorporates a normally closed pilot-operated traction control switching valve to permit brake pressure in the driven wheel greater than master cylinder pressure. A dual flow return path can be used during brake release. The system also uses a normally open pilot-operated supply valve between the pump inlet and the master cylinder. The normally open pilot-operated valve references a low pressure fluid source and uses low friction seals.

Abstract: An antilock/traction control/vehicle stability braking system hydraulic circuit using a fluid flow intensifier to provide a rapid application of fluid pressure to brakes during a TC/vehicle stability control operation at a flow rate that is greater than is normally available from an ABS pump alone. The intensifier increases the fluid flow as a function of using a stepped piston operating within respective input and output chambers having different effective diameters. The intensifier also includes an intermediate chamber into which fluid dumped from a brake cylinder is drawn rather than being lost to a master cylinder reservoir. The fluid thus remains in the hydraulic circuit, ensuring that a desired ratio of pedal travel versus pressure is maintained after a transition from TC/vehicle stability braking to ABS-base braking.

Abstract: An anti-lock brake system having a switchable orifice control valve disposed between the master brake cylinder and the brake assembly. The switchable orifice control valve, having a valve body, a stationary member, a movable member and a solenoid coil actuated armature. The switchable orifice control valve has a normally open state, a closed state and a third state during an anti-lock mode of operation. In the third state the brake fluid from the master brake cylinder to the brake assembly flows through a calibrated re-apply orifice which controls the rate at which the pressure of the fluid being applied to the brake assembly is increased at a predetermined rate. The switchable orifice control valve is held in the third state by a pressure differential orifice between the input and output ports of the switchable orifice control valve.

Abstract: A passive system is disclosed for controlling the roll of a motor vehicle. The system comprises an actuator connected between an unsprung portion of the vehicle and a sprung portion of the vehicle, first and second pressure control valves, and first and second check valves. The first pressure control valve is in communication with a first port of the actuator and has a first position where flow away from the first port is prevented up to a predetermined pressure. The first check valve is in parallel with the first pressure control valve. The second pressure control valve is in communication with a second port of the actuator and has a first position where flow away from the second port is prevented up to a predetermined pressure. The second check valve is in parallel with the second pressure control valve.

Abstract: An apparatus is disclosed for controlling the roll of a motor vehicle. The apparatus comprises an anti-roll bar, a hydraulic circuit, an actuator, and a pair of valves. The hydraulic circuit includes a pump and a power steering rack disposed downstream from the pump. The actuator is coupled between the anti-roll bar and an unsprung portion of the vehicle. In one embodiment of the invention, the actuator comprises a piston having a wrist pin rotatable therein and engaged with the anti-roll bar, the piston being reciprocable against a force to counteract the twisting of the anti-roll bar. The first valve is situated in the hydraulic circuit upstream of the power steering rack and selectively establishes a pressure differential thereacross.

Abstract: A master cylinder having, in addition to a main pressurizing chamber, a fast-fill pressurizing chamber to quickly force, while pedal effort is minimal, brake pads or shoes from initially retracted positions to positions where the pads or shoes are in contact with corresponding brake disks or drums. The present master cylinder uses no fixed brake fluid flow restriction valves to vent brake fluid from the fast-fill pressurizing chamber once contact is made, pedal travel being made thereby independent of the rate of applied pedal effort.

Abstract: A traction control low-restriction check valve for use in a compensating port master cylinder used with a traction control system and an antilock braking system. The check valve is a poppet valve mounted in a primary piston of the master cylinder. The popper valve is resiliently biased in a sealing position but allows brake fluid to be drawn by a traction control pump from a brake fluid reservoir against the resilient bias when the primary piston is not being translated to increase brake fluid pressure within the master cylinder.