Abstract: A disc brake caliper assembly has a housing with a bore. A piston in the bore is movable between applied, retracted and knock-back positions. The piston is activatable by hydraulic pressure to move from the retracted position to the applied position; and a retracting seal is effective in the absence of the hydraulic pressure to move the piston from the applied position to the retracted position. A linkage adjacent the piston carries a stop; and an actuator is responsive to an end of brake activation signal to cause the linkage to engage the stop with the piston when the piston is retracted from its applied position to its retracted position so as to prevent the piston from moving from the retracted position to the knock-back position. The actuator is preferably a comparatively weak electric motor that stalls as the stop engages the piston; and the stall is sensed to end motor activation. The end of brake activation signal is preferably provided by a brake position or pressure sensor.

Abstract: A brake system and method of controlling the system are disclosed. The system provides secondary hydraulic braking in a de-energized mode. The system includes a wheel brake associated with wheels of a vehicle typically at each corner of the vehicle. The wheel brake typically includes a caliper or drum for deceleration of the vehicle. The system includes a master cylinder in fluid communication with the wheel brake. In the de-energized mode, the master cylinder operates the wheel brake. A solenoid isolation valve decouples the master cylinder from the wheel brake when the system is in a normal, i.e., an energized, mode. As such, the master cylinder is isolated from the wheel brake and is prevented from operating the wheel brake. Alternatively, in the de-energized mode, the isolation valve couples the master cylinder with the wheel brake to provide the secondary hydraulic braking.

Abstract: A disc brake caliper assembly is provided that includes a housing having a bore. A piston is arranged within the bore and is movable between normal retracted and knock-back positions. A linkage is adjacent to the piston and is movable between first and second positions with a clearance between the piston and the linkage in the first position. The clearance undesirably permits the piston to move to the knock-back position during severe operating conditions. An actuator, which also may be used as part an electric parking brake, moves the linkage from the first position to the second position to eliminate the clearance when the linkage is moved from the first position to the second position where the linkage abuts the piston. The linkage is connected to the caliper housing by a support. The linkage prevents the piston from moving from the normal retracted position to the knock-back position.

Abstract: A brake system and method of controlling the system are disclosed. The system provides secondary hydraulic braking in a de-energized mode. The system includes a wheel brake associated with wheels of a vehicle typically at each corner of the vehicle. The wheel brake typically includes a caliper or drum for deceleration of the vehicle. The system includes a master cylinder in fluid communication with the wheel brake. In the de-energized mode, the master cylinder operates the wheel brake. A solenoid isolation valve decouples the master cylinder from the wheel brake when the system is in a normal, i.e., an energized, mode. As such, the master cylinder is isolated from the wheel brake and is prevented from operating the wheel brake. Alternatively, in the de-energized mode, the isolation valve couples the master cylinder with the wheel brake to provide the secondary hydraulic braking.

Abstract: A disc brake caliper with an integral parking brake includes a caliper housing defining a cavity therein and a piston axially translatable within the cavity and having an internal bearing surface. At least one brake pad is affixed to either the piston or the caliper housing. A parking brake mechanism is mounted within the cavity and is interposed between a portion of the housing and the piston. The parking brake mechanism includes a thrust pin substantially axially aligned with the piston and rotatable within the housing. A first radial clutch is engageable with the thrust pin, and a second axial clutch is operable upon the piston. Rotation of the thrust pin in a first direction causes engagement of the first radial clutch and of the second axial clutch causing axial displacement of the piston. Rotation of the thrust pin in an opposite direction causes disengagement of the first and said second clutches.

Abstract: A disc brake caliper with an integral parking brake includes a caliper housing defining a cavity therein and a piston axially translatable within the cavity and having an internal bearing surface. At least one brake pad is affixed to either the piston or the caliper housing. A parking brake mechanism is mounted within the cavity and is interposed between a portion of the housing and the piston. The parking brake mechanism includes a thrust pin substantially axially aligned with the piston and rotatable within the housing. A first radial clutch is engageable with the thrust pin, and a second axial clutch is operable upon the piston. Rotation of the thrust pin in a first direction causes engagement of the first radial clutch and of the second axial clutch causing axial displacement of the piston. Rotation of the thrust pin in an opposite direction causes disengagement of the first and said second clutches.

Abstract: A disc brake caliper assembly has a housing with a bore. A piston in the bore is movable between applied, retracted and knock-back positions. The piston is activatable by hydraulic pressure to move from the retracted position to the applied position; and a retracting seal is effective in the absence of the hydraulic pressure to move the piston from the applied position to the retracted position. A linkage adjacent the piston carries a stop; and an actuator is responsive to an end of brake activation signal to cause the linkage to engage the stop with the piston when the piston is retracted from its applied position to its retracted position so as to prevent the piston from moving from the retracted position to the knock-back position. The actuator is preferably a comparatively weak electric motor that stalls as the stop engages the piston; and the stall is sensed to end motor activation. The end of brake activation signal is preferably provided by a brake position or pressure sensor.

Abstract: A brake by wire system provides the capability of both travel and force sensors on a brake apply input member such as a brake pedal and also provides redundancy in sensors by providing the signal from a sensor responsive to travel or position of the brake pedal to a first controller and the signal from a sensor responsive to force applied to the brake pedal to a second controller. The first and second controllers are connected by a bi-directional communication link whereby each controller may communicate its received one of the sensor signals to the other controller. In at least one of the controllers, linearized versions of the signals are combined for the generation of first and second brake apply command signals for communication to brake apply units. If either controller does not receive one of the sensor signals from the other, it nevertheless generates its brake apply command signal on the basis of the sensor signal provided directly to it from the sensor.

Abstract: A braking assembly for providing a braking force to a wheel brake of a vehicle based upon receipt of an electrical brake signal is provided. The brake assembly comprises an actuator including a motor that applies and releases a piston within an actuator body. The actuator is fluidly connected to a wheel brake whereby the wheel brake can be applied and released. A solenoid valve is interposed between the actuator and the wheel brake on a primary fluid path for opening and closing the fluid connection. A step piston is placed within a secondary fluid path between the actuator and the wheel brake and operates to momentarily increase fluid displacement applied to the wheel brake when the solenoid valve closed.

Abstract: Improved control for a hydraulic system useful in automotive braking applications, particularly in dry interface automotive braking applications, includes the use of a valve for holding pressure in a hydraulic system constant while relieving the pressure load on the pressure source. Preferably, the valve is a normally-open solenoid valve that is closed and opened in response to a desired pressure being sensed at a pressure actuated mechanism, such as a brake caliper. The use of the improved control for a hydraulic system improves brake response times during ABS applications, and increases the energy efficiency and life expectancy of the pressure providing motor.

Abstract: A brake by wire system provides the capability of both travel and force sensors on a brake apply input member such as a brake pedal and also provides redundancy in sensors by providing the signal from a sensor responsive to travel or position of the brake pedal to a first controller and the signal from a sensor responsive to force applied to the brake pedal to a second controller. The first and second controllers are connected by a bi-directional communication link whereby each controller may communicate its received one of the sensor signals to the other controller. In at least one of the controllers, linearized versions of the signals are combined for the generation of first and second brake apply command signals for communication to brake apply units. If either controller does not receive one of the sensor signals from the other, it nevertheless generates its brake apply command signal on the basis of the sensor signal provided directly to it from the sensor.

Abstract: An electro-hydraulic actuator for a motor vehicle brake-by-wire brake system including a housing, a piston bore in the housing, a T-shaped piston in the piston bore, and an electric motor connected to the piston through a speed reducer. The T-shaped piston includes a disc-shaped head in the piston bore and a tubular stem perpendicular slidable in and out of the piston bore through a sealed guide in the bottom of the piston bore. The top side of the piston head opposite the stem constitutes a large effective area of the piston for rapidly expelling a relatively large volume of fluid from the piston bore in a low pressure interval of operation the actuator. When the fluid pressure in the piston bore exceeds a transition pressure, a transition valve opens a bypass passage to the piston bore behind the piston head so that the same fluid pressure reacts against the bottom side of the piston head around the stem.

Abstract: A master cylinder provides separate flow paths through its secondary piston to provide greater fluid flow capacity from the reservoir to both the primary and secondary pressure chambers in response to the removal of brake fluid from the brake lines fed by the primary and secondary pressure chambers by a pump providing brake pressure for activation of one or more wheel brakes independently of the master cylinder. The secondary piston is provided with an axial fluid flow passage having check valves at each axial end permitting fluid flow only out of the axial fluid flow passage into the primary and secondary pressure chambers. A cross flow passage intersects the axial fluid flow passage between the primary and secondary check valves to communicate the axial fluid flow passage with the intermediate chamber and thus with the reservoir through the secondary compensation opening. The additional flow capacity to both pressure chambers provides improved reaction time for a traction control system at any wheel brake.

Abstract: A brake apply system includes a pressure charging module having a bore carrying a pumping piston that has a base piston surface and an augmentation piston surface. The pressure charging piston separates the bore into an input chamber adjacent the base piston surface and an output chamber adjacent the augmentation piston surface. A suspension damper is hydraulically connected to the input chamber of the pressure charging module, preferably through a continuously open fluid communication circuit. A wheel brake is hydraulically connected to the accumulator output chamber through a selectively open fluid communication circuit.

Abstract: A brake apply system includes a modulator that has a first bore carrying a power driven dual-effect piston. The piston has a base piston surface and an augmentation piston surface. A wheel brake is hydraulically connected to the modulator through an open fluid communication route that is provided between the wheel brake and the base piston surface. A selectively open fluid communication route is provided between the wheel brake and the augmentation piston surface with a check valve mechanism positioned in the selectively open fluid communication route. An augmentation chamber is defined adjacent the augmentation surface of the dual-effect piston. The modulator includes a second bore carrying a valve mechanism that provides an open flow path between the augmentation chamber and a reservoir when pressure at the wheel brake is relatively high and that significantly restricts the flow path when the wheel brake pressure is relatively low.

Abstract: A pressurized brake bleed system includes a rigid container, a flexible container containing brake fluid disposed within the rigid container, a hose having one end connected to the flexible container and another end for connection to a fluid reservoir of a brake system and a structure to apply a force to pressurize the flexible container to bleed the brake fluid from the flexible container through the hose to the fluid reservoir.

Abstract: A brake pedal feel emulator includes a piston that is movable against the force of a compressible elastomeric body and fluid force. The emulator supplies conventional pedal feel and travel characteristics when the primary and secondary pistons of the brake system's master cylinder are substantially movable due to isolation of the master cylinder from the wheel brakes. The fluid force is supplied by controlling the flow of fluid from behind the emulator piston through a flow restrictive orifice to a conventional fluid reservoir on the master cylinder assembly. The emulator is operable with electric or electro-hydraulically controlled braking system.

Abstract: A master cylinder and emulator includes a primary piston and a secondary piston which are movable to provide fluid pressure to effect wheel braking in a vehicle. In addition, the master cylinder includes an emulator assembly which supplies conventional pedal feel and travel characteristics when the primary and secondary pistons are substantially immovable due to isolation of the master cylinder from the wheel brakes. The emulator assembly includes a piston that is movable against a selected amount of fluid pressure and spring force while the primary piston remains stationary. The fluid force is supplied by controlling the flow of fluid from behind the piston through a flow restrictive orifice to a conventional fluid reservoir on the master cylinder assembly. The master cylinder and emulator assembly is operable to provide brake actuation assist to an electric or electro-hydraulically controlled braking system.

Abstract: A rotary actuated braking system includes a motor driven shaft that operates two pairs of piston pumps and an allocation valve which, in combination with a single solenoid valve, effects ABS operation of the braking system. A combination of pressure operated control valves and pressure operated release valves for each control wheel brake respond to operation of the rotary actuator and solenoid valve to effect ABS pressure release and reapply from the corresponding wheel brake. A power boosted master cylinder provides base brake operation independent of the rotary actuator effected ABS operation.

Abstract: A power brake apply system includes a master cylinder having a piston for generating fluid pressure within a braking circuit. A boost valve assembly is mounted adjacent the master cylinder and carries a slidable spool that selectively closes off a normal path of communication between a fluid reservoir and the boost chamber of the master cylinder in response to the manual actuation of the master cylinder's piston as effected through a pressurized braking circuit. After closure of communication between the reservoir and the boost chamber a power fluid supply is opened to the boost chamber to provide power assist in the actuation of the master cylinder's piston.