A brake device includes a first flow path unit guiding a braking hydraulic pressure by connecting some of wheel cylinder units and a master cylinder unit; a second flow path unit guiding a braking hydraulic pressure by connecting the others of the wheel cylinder units and the master cylinder unit; a third flow path unit connecting a reservoir and pump units, and connected with the first flow path unit; a fourth flow path unit connecting the reservoir and the pump units, and connected with the second flow path unit; a fifth flow path unit connecting the reservoir and the first flow path unit; a sixth flow path unit connecting the reservoir and the second flow path unit; a seventh flow path unit selectively connecting the first and second flow path units; and an eighth flow path unit connecting the second flow path unit and the reservoir.

In the present invention, a brake device is equipped with: differential pressure control valves; pressure adjusting units which are connected to the differential pressure control valves through liquid passages; and a control device which controls the WC pressure Pwc in wheel cylinders by operating the differential pressure control valves and the pressure adjusting units. When predetermined suppression control permission conditions are satisfied while both the supply pumps of the pressure adjusting units and the differential pressure control valves are in operation, the control device performs self-excited vibration suppression control over the differential pressure control valves, the self-excited vibration suppression control being carried out in such a manner that a valve element separated from a valve seat is caused to abut on the valve seat, and, upon abutting on the valve seat, the valve element is separated from the valve seat.

The method relates to a method for boosting the braking force in an electromotor operated slip-controllable vehicle brake system having electromechanical brake boosting. The vehicle brake system includes a braking-intention detection device, an electromechanically actuatable brake booster, and an electronically actuatable brake-pressure control device. In the event of a malfunction of the brake booster, the boosting of the brake pressure is alternatively assumed by the brake-pressure control device. In the event of a malfunction of the brake boosting, it is checked whether a generation and a transmission of a trigger signal representing the actuation of the braking-intention detection device from the first electronic control device of the brake booster to a second electronic control device of the brake-pressure control device is possible, and if this is so, the trigger signal is transmitted via an existing communications link between the control devices.

Disclosed is an electronic brake system including: a reservoir to store oil; a master cylinder connected to the reservoir and including first and second master chambers and first and second piston provided in the first and second master chambers, respectively, to discharge the oil according to an pedal effort of a brake pedal; a hydraulic pressure generating apparatus provided on at least one of a first reservoir passage connecting the reservoir and the first master chamber and a second reservoir passage connecting the reservoir and the second master chamber; a hydraulic pressure supply apparatus operated by an electrical signal to generate a hydraulic pressure and connected to the master cylinder; and a hydraulic pressure control unit transmitting alternatively the hydraulic pressure discharged from the hydraulic pressure generating apparatus or the hydraulic pressure supply apparatus to a wheel cylinder provided on each of four wheels.

A master cylinder and an electronic brake system including the same are disclosed. The electronic brake system includes a main hydraulic-pressure supply device to generate hydraulic pressure by sensing displacement of a brake pedal and a sub hydraulic-pressure supply unit to supply hydraulic pressure to at least one wheel cylinder during an abnormal operation of the main hydraulic-pressure supply device. The master cylinder includes a first piston disposed in a bore of a cylinder body so as to be directly pressurized by the brake pedal, a first hydraulic chamber pressurized by the first piston to discharge hydraulic pressure, a second piston indirectly pressurized by the first piston, and a second hydraulic chamber pressurized by the second piston to discharge hydraulic pressure. The second hydraulic chamber includes a slippage prevention means connected to the sub hydraulic-pressure supply unit so as to prevent the second piston from moving toward the first piston by the hydraulic pressure received from the sub hydraulic-pressure supply unit.

A method for operating a vehicle brake system, including activation of a electrohydraulic brake booster device when there is an actuation of a brake actuating element, so a brake pressure increase is brought about in a wheel brake cylinder, and decoupling of the wheel brake cylinder from a master brake cylinder of the brake system by closing a separating valve, it being ascertained, before the closing of the separating valve, whether a first quantity relating to an actuation speed of the actuation of the brake actuating element and/or a second quantity relating to a master brake cylinder pressure increase is within at least one specified normal value range, and, if warranted, the separating valve being closed without a delay, whereas otherwise the closing of the separating valve is delayed taking into account the second quantity and/or a third quantity relating to the brake pressure increase.

A brake system for actuating a pair of front wheel brakes and a pair of second wheel brakes. The brake system includes a reservoir and a brake pedal unit having a housing with first and second pistons slidably disposed in the housing. The first and second pistons are operable during a manual push-through mode by actuation of a brake pedal connected to the brake pedal unit. The first and second pistons are movable to generate brake actuating pressure at first and second outputs for actuating the pair of front wheel brakes and the pair of rear wheel brakes. A first source of pressurized fluid actuates the pair of front wheel brakes and the pair of rear wheel brakes during a non-failure normal braking event. A first electronic control unit controls the first source of pressurized fluid. A second source of pressurized fluid is hydraulically connected to the brake pedal unit and actuates the brake pedal unit to cause movement of the first and second pistons for generating pressure at the first and second outputs. A second electronic control unit, separate from the first electronic control unit, controls the second source of pressurized fluid.

A system includes a computer including a processor and a memory, the memory storing instructions executable by the processor to actuate a brake valve to drain a brake cylinder and then actuate the brake valve to isolate the brake cylinder and hold a brake pedal in a retracted position.

A braking control device drives an electric motor based on a command pressing force corresponding to the required wheel braking force, and presses a friction member against a rotation member fixed to the wheel to generate a wheel braking force. The braking control device includes: a sensor for detecting wheel speed; a sensor for detecting the actual pressing force applied by the friction member; and a controller for calculating the target pressing force based on the command pressing force, and controlling the motor so that the target and actual pressing forces match. The controller calculates wheel slip state quantity based on the wheel speed, and executes, based on the slip state quantity, slip suppression control for reducing the degree of wheel slippage. Based on the actual pressing force at the start of the slip suppression control, the controller reduces the command pressing force and calculates the target pressing force.

An electrohydraulic actuator assembly for use in a brake-by-wire hydraulic brake system. The electrohydraulic actuator assembly includes a pair of electrohydraulic actuator EHA units. One EHA unit provides fluid to front brakes and the other EHA unit provides fluid to rear brakes. Each EHA unit includes an electric motor, a reduction gear unit, a pair of magnetorheological clutches, and a pair of fluid pumps. The system further including an ECU that actuates the electric motor and controls engagement of the clutches to cause the fluid pump to pump brake fluid to at least one of the front and rear brakes. The system further includes a regeneration system for providing supplemental electricity to the electric motors.