Kelsey-hayes Company

Lucas Industries Limited

Varity Gmbh

Varity Kelsey-hayes Gmbh

Andrew W Kingston

Thomas Weigert

Salvatore Oliveri

Robert L Ferger

Mark S Luckevich

Blaise J Ganzel

Alan Leslie Harris

Gregory P Campau

Gregor Poertzgen

Herbert L Linkner, Jr

Peter Every

Barry John Bridgens

Peter Martin

Karl-Friedrich Worsdorfer

Michael John Holt

Leonard Tribe

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. The brake system of the invention further includes a relatively low cost fluid separator unit which is provided which prevents intermixing of pressurized fluid between the backup source and the normal source. The fluid separator unit acts to permit the normal source to act upon the hydraulic brake fluid of the backup source to operate the vehicle brakes. The fluid separator unit is preferably embodied as a piston having two working faces, each of the same diameter.

Electronic brake management system with manual fail safe

A vehicle braking system of the type in which a stored volume of fluid is used to apply the wheel brakes of the vehicle under the control of an electronic unit, the stored volume being held in an accumulator arranged to be replenished by pumping additional working fluid using a pump driven by an electric motor. The speed of the pump electric motor is arranged to be controlled in dependence upon whether or not any vehicle dynamic intervention, such as ABS, TC and VSC, is active. If it is deduced that one or more vehicle dynamic functions is active, then the pump is arranged to be run at high/full, and relatively noisy, speed, but if it is concluded that only base braking is being applied with no vehicle dynamic function being active, then the pump is arranged to be operated at a relative slower and hence quieter speed.

Pump motor control in electro-hydraulic braking systems

A pedal simulator utilizing springs to provide a brake pedal with a non-linear, progressively increasing response characteristic for pedal travel versus force exerted on the brake pedal similar to a conventional hydraulic braking system. In a preferred embodiment, the pedal simulator is integrated into the housing of an associated master cylinder. The non-linear, progressively increasing response characteristic is provided in one embodiment by a conical spring having a non-uniform helix angle. In second and third embodiments, the non-linear, progressively increasing response characteristic is provided by a plurality of cylindrical coil springs.

Pedal simulator using spring with non-linear response

An electro-hydraulic braking system for motor vehicles. The system includes a brake pedal and a braking device associated with at least one vehicle wheel which is brought into communication with an electronically controlled valve arrangement in order to apply hydraulic fluid under pressure to the braking device. A fluid pressure accumulator fed by the pump provides a pressurized hydraulic fluid which can be passed to the braking device by way of an electronically controlled valve arrangement in order to apply hydraulic fluid in proportion to the driver braking demand as sensed at the brake pedal in the &ldquo;brake by wire&rdquo; mode. A first device within the system provides a level of fluid pressure supply within the electro-hydraulic system whose highest value is less than that sufficient for the maximum possible braking demand level which may be required. A second device within the system recognizes a braking demand level which exceeds that which can be achieved by the highest value of fluid pressure available by the first device and establishes a higher level of fluid pressure supply within the system for controlling the brakes in accordance with the driver's demanded braking level.

Electro-hydraulic braking systems

An electrically actuated hydraulic power cylinder for use in a vehicle braking system. The power cylinder includes an electric motor, a rotary-to-linear actuator for converting rotary motion of the electric motor to a linear motion, and a hydraulic cylinder. In a preferred embodiment, the rotary-to-linear actuator is a roller screw assembly. The roller screw assembly converts rotational motion generated by the motor into axial movement of a piston which is disposed within the hydraulic cylinder. The movement of the piston pressurizes a volume of fluid. The pressurized fluid flows through an outlet port connected to either a single wheel brake cylinder or a plurality of wheel brake cylinders, thereby actuating the associated wheel cylinder. In a specific embodiment of the invention, the roller screw assembly is incorporated into the internal structure of the motor for compactness and weight reduction. Also, the hydraulic cylinder may be integrated into a wheel brake assembly for compactness and weight reduction.

Electrically actuated hydraulic power cylinder

A brake control system determines utilizes a sensed amount of brake travel and a sensed amount of master cylinder pressure in determining a base brake control signal for an electro-hydraulic brake management system. The system also provides a springer function to provide an appropriate amount of brake jump-in, based on vehicle velocity and pedal travel. For pure brake-by-wire systems that have no hydraulic components, brake force is substituted for master cylinder pressure in determining a base brake control signal.

Foundation brake control algorithm for electro-hydraulic brake system and brake-by-wire system

An actuation unit for an electronically controlled hydraulic vehicle braking system, comprising a brake booster which can be actuated by a brake pedal and which comprises a master cylinder and a reservoir for hydraulic fluid, a first brake which is coupled with at least a first vehicle wheel and which is connectable with the master cylinder via an electronically controlled valve arrangement in a basic position or, in an actuation position is disconnectable from same, a brake pedal behaviour simulator which is connectable with the master cylinder and comprises a spring arrangement adapted to act against the hydraulic pressure from the master cylinder, and with which a characteristics modeling is associated.

Actuation unit for an electronically controlled vehicle brake system

A pedal simulator for a vehicle braking system. The pedal simulator is coupled to a brake pedal, and includes an electrical actuator operatively coupled to the brake pedal to selectively exert a force on the brake pedal. A position sensor is provided for generating a position signal indicative of the position of the brake pedal. A force sensor is provided for generating a force signal indicative of the force exerted upon the brake pedal by a driver. An electronic control unit is provided which has programmed therein a desired relationship between the position signal and the force signal. The electronic control unit determines an actual relationship between the position signal and the force signal and compares the actual relationship thus determined with the desired relationship. The electronic control unit controls the electrical actuator to selectively exert a force on the brake pedal to conform the actual relationship to the desired relationship.

Programmable electronic pedal simulator

An improved structure for an electrical actuation mechanism adapted for use in a disc brake assembly includes an electrical actuation mechanism adapted to be secured to an inboard leg of the caliper of the disc brake assembly. The electrical actuation mechanism includes a housing, an electrical motor disposed in the housing, and a spindle disposed in the housing and operatively coupled to the motor by a conversion gear assembly which is effective to convert rotary motion generated by the motor into axial movement of the piston. The spindle includes a shaft and a piston which can be coupled to the shaft by a dampening structure. The shaft is operatively connected to the motor for axial motion thereof, and the piston is operatively connected to a friction pad for engaging a rotor attached to a wheel of a vehicle in which the disc brake assembly is installed. The dampening structure can be comprised of elastomeric material or a fluid filled chamber defined between the piston and the shaft. The dampening structure reduces the radial loads acted upon the piston from being transmitted to the shaft. The electrical actuation mechanism may also be equipped with sensors for sensing the axial position of the piston, a clutch, to couple and uncouple the electric motor from the conversion gear assembly, and a mechanism which prevents back drive motion of the electrical motor.

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Heidesheim, Germany

Andrew W Kingston