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US 5,823,636 AGranted
Vehicle braking system
AssigneeGeneral Motors Corporation
InventorsDonald Lee Parker, Donald Edward Schenk, Schuyler Scott Shaw
Life of this patent
Estimating the term…
Abstract
A vehicle braking system that primarily operates as a pure brake-by-wire system, with optional hydraulic actuation. The system includes a set of four electrically actuated drum brakes. At least two of the wheel brakes include hydraulic actuators that operate to apply the wheel brakes independent of electric control. Each of the wheel brakes is normally operated in response to a control signal generated by the vehicle's brake processor. As such, a primary brake-by-wire system is provided at all four vehicle wheels. The rear brakes are proportioned to the front brakes electrically, according to design criteria.
Claims10
A vehicle braking system comprising:
- a wheel brake having a backing plate, at least one brake shoe movably mounted to the backing plate, an electric driven power screw actuator mounted to the backing plate, an apply lever pivotally engaging the actuator, and a hydraulic actuator engaging the brake shoe;
- a master cylinder with a hydraulic port;
- a brake line extending between the hydraulic port of the master cylinder and the hydraulic actuator of the wheel brake;
- a brake pedal;
- a pushrod interconnected between the brake pedal and the master cylinder wherein the master cylinder is actuated in response to the application of a force to the brake pedal;
- a transducer monitoring application of the brake pedal;
- an electrically actuated valve interposed in the brake line wherein the valve has three ports, a first port communicating with the hydraulic port of the master cylinder, a second port communicating with the hydraulic port of the wheel brake and a third port, wherein the first port is normally open to the second port through the valve;
- a pedal feel emulating device communicating with the third port of the valve;
- and
- an electronic controller monitoring the transducer and operating to effect movement of the valve to a position wherein the first port is in communication with the third port and the second port is closed, and operating to effect operation of the electric motor driven power screw actuator to apply the wheel brake, and wherein, when an electrical signal to the valve is absent, actuation of the wheel brake is effected through hydraulic pressurization in the master cylinder with pressure communicated to the hydraulic actuator of the wheel brake through the brake line and the valve.
7 more elements
A vehicle braking system comprising:
- a wheel brake having a backing plate, a first brake shoe having an upper end and a lower end and movably mounted to the backing plate, a second brake shoe having an upper end and a lower end and movably mounted to the backing plate, an electric driven power screw actuator mounted to the backing plate near the upper ends of the first and second brake shoes, an apply lever pivotally engaging the actuator and engaging the second brake shoe near the lower end of the second brake shoe, and a hydraulic actuator engaging the lower ends of the first and second brake shoes;
- a master cylinder with a hydraulic port;
- a brake line extending between the hydraulic port of the master cylinder and the hydraulic actuator of the wheel brake;
- a brake pedal;
- a pushrod interconnected between the brake pedal and the master cylinder wherein the master cylinder is actuated in response to the application of a force to the brake pedal;
- a transducer monitoring the amount of force applied to the brake pedal;
- an electrically actuated valve interposed in the brake line wherein the valve has three ports, a first port communicating with the hydraulic port of the master cylinder, a second port communicating with the hydraulic port of the wheel brake and a third port, wherein the first port is normally open to the second port through the valve;
- a pedal feel emulating device communicating with the third port of the valve;
- and
- an electronic controller monitoring the transducer and operating to effect movement of the valve to a position wherein the first port is in communication with the third port and the second port is closed, and operating to effect operation of the electric motor driven power screw actuator to apply the wheel brake, and wherein, when an electrical signal to the valve is absent, actuation of the wheel brake is effected through hydraulic pressurization in the master cylinder with pressure communicated to the hydraulic actuator of the wheel brake through the brake line and the valve.
7 more elements
A vehicle braking system comprising:
- a wheel brake having a backing plate, a first brake shoe with an upper end and a lower end and movably mounted to the backing plate, a second brake shoe with an upper end and a lower end and movably mounted to the backing plate, an electric driven power screw actuator mounted to the backing plate near the upper ends of the first and second brake shoes, an apply lever pivotally engaging the actuator and engaging the second brake shoe near the lower end of the second brake shoe, and a hydraulic actuator fixed to the backing plate, wherein the hydraulic actuator includes a body carrying a first plunger engaging the lower end of the first brake shoe and carrying a second plunger engaging the lower end of the second brake shoe and wherein a post extends from the body of the hydraulic actuator and wherein at least one shoe return spring engages the post;
- a master cylinder with a hydraulic port;
- a brake line extending between the hydraulic port of the master cylinder and the hydraulic actuator of the wheel brake;
- a brake pedal;
- a pushrod interconnected between the brake pedal and the master cylinder wherein the master cylinder is actuated in response to the application of a force to the brake pedal;
- a transducer monitoring the amount of force applied to the brake pedal;
- an electrically actuated valve interposed in the brake line wherein the valve has three ports, a first port communicating with the hydraulic port of the master cylinder, a second port communicating with the hydraulic port of the wheel brake and a third port, wherein the first port is normally open to the second port through the valve;
- a pedal feel emulating device communicating with the third port of the valve;
- and
- an electronic controller monitoring the transducer and operating to effect movement of the valve to a position wherein the first port is in communication with the third port and the second port is closed, and operating to effect operation of the electric motor driven power screw actuator to apply the wheel brake, and wherein, when an electrical signal to the valve is absent, actuation of the wheel brake is effected through hydraulic pressurization in the master cylinder with pressure communicated to the hydraulic actuator of the wheel brake through the brake line and the valve.
7 more elements
Dependencies are inferred from the claim text.