A control apparatus for an electromechanical-brake-booster of a vehicle, having: an electronic-device to control an electric-motor of the electromechanical-brake-booster so that an output piston, connected indirectly to the electric-motor, of the electromechanical-brake-booster is displaceable out of its initial-position by the controlled electric-motor, such that only after a displacement of the output-piston out of its initial-position by at least a predefined limit displacement travel does a frictional engagement exist between the output-piston and an input-piston that is indirectly connected to the brake-pedal and is displaced by the actuation of the brake-pedal, and such that a speed of the output-piston displaced out of its initial-position by less than the limit displacement travel is at first increased from a reference-speed to a maximum-speed and is then reduced from the maximum-speed to the reference-speed. The invention furthermore relates to a method for operating an electromechanical-brake-booster of a vehicle.

Provided are an apparatus for braking using an electric booster and a control method thereof. The apparatus for braking using an electric booster includes an electric booster connected to a master cylinder and configured to discharge braking hydraulic pressure by pressing a piston of the master cylinder with electric power of a motor together with a driver's pedal force, an electric hydraulic braking unit connected to the master cylinder through hydraulic lines, and configured to store braking hydraulic pressure in an accumulator and to perform ESC braking by driving a pumping motor, and a control unit configured to control the electric booster and the electric hydraulic braking unit, to compare required braking hydraulic pressure with preset reference hydraulic pressure when the ESC braking is required, and to perform ESC braking by the electric hydraulic braking unit or braking by the electric booster according to a result of the comparison.

A braking force control device is provided which has a control unit that controls an upstream braking actuator that generates a common upstream pressure for four wheels and a downstream braking actuator that individually controls the braking pressure supplied to each wheel using the upstream pressure. The control unit controls the upstream pressure so that the braking pressure of the front wheels is permitted to be higher than a lock pressure of the rear wheels but does not become higher than a lock pressure of the front wheels, and suppresses an increase of the braking pressure of the rear wheels so that the braking pressure does not become higher than the lock pressure of the rear wheels, in a situation where the upstream pressure can be supplied to each braking force generating device but the braking pressure of any one of the wheels cannot be decreased.

An integrated power brake unit (20) includes an input rod (30) operable to receive a driver braking input force, a booster operable to boost the driver braking input force, a master cylinder, a pump operable to provide pressurized fluid for braking, in lieu of the master cylinder, in response to the driver braking input force, and a fluid reservoir (36) defining a main chamber. The fluid reservoir (36) has first and second outlet ports (P1, P2) in fluid communication to supply the master cylinder, and a third outlet port (P3) in fluid communication to supply the pump, each of the first, second, and third outlet ports (P1, P2, P3) being provided in a bottom wall (48) of the fluid reservoir (36). The fluid reservoir (36) includes a sub-chamber (42) within the main chamber, the sub-chamber (42) covering the third outlet port (P3), and defining an opening (56) to the main chamber at a forward-most end of the sub-chamber (42).

The vehicle braking device includes a pilot pressure control portion which executes normal control in which the pilot pressure is controlled in response to the target value of the servo pressure and shortening control in which the change amount of the pilot pressure per unit time is greater than the change amount under the normal control in a mutually different timing, a state judging portion which judges the state of the master piston relating hysteresis of sliding resistance of the master piston based on the detection result of the servo pressure detecting portion or the liquid pressure co-relating with the servo premeasure and a control switching over portion which terminates the shortening control based on the detection result of the servo pressure detecting portion and the detection result of the state judging portion.

A brake system having a wheel brake and being operable under a non-failure normal braking mode and a manual push-through mode. The system includes a master cylinder operable by a brake pedal during the manual push-through mode to provide fluid flow at an output for actuating the wheel brake. A first source of pressurized fluid provides fluid pressure for actuating the wheel brake under the normal braking mode. A second source of pressurized fluid generates brake actuating pressure for actuating the wheel brake under the manual push-through mode.

The hydraulic pressure generating device includes a regulator (spool valve) formed by a cylinder body, a spool which slidably moves within the cylinder body, a pilot chamber in which a pilot pressure which is a hydraulic pressure moving the spool along in an axial direction is inputted and an output chamber out of which an output pressure which is a hydraulic pressure corresponding to the pilot pressure is outputted, wherein the hydraulic pressure generating device further includes a spool position obtaining portion which obtains a relative position of the spool relative to the cylinder body and a pilot pressure controlling portion which controls the pilot pressure based on the relative position obtained by the spool position obtaining portion.

The vehicle braking device performs a control which makes an actual value of physical quantity associated with a braking force follow a target value thereof when the actual value is outside a dead zone and a control which suppresses a change of the actual value when the actual value is within the dead zone and includes a judging portion which judges whether or not the actual value passes through the dead zone with a value beyond the upper limit threshold value and a setting portion which sets a second upper limit threshold value more closely approximated than a first upper limit threshold value when the actual value is judged not to pass through the dead zone, as the upper limit threshold value, when the actual value is judged to pass through the dead zone by the judging portion.

An integrated power brake unit (20) includes an input rod (30) operable to receive a driver braking input force, a booster operable to boost the driver braking input force, a master cylinder, a pump operable to provide pressurized fluid for braking, in lieu of the master cylinder, in response to the driver braking input force, and a fluid reservoir (36) defining a main chamber. The fluid reservoir (36) has first and second outlet ports (P1, P2) in fluid communication to supply the master cylinder, and a third outlet port (P3) in fluid communication to supply the pump, each of the first, second, and third outlet ports (P1, P2, P3) being provided in a bottom wall (48) of the fluid reservoir (36). The fluid reservoir (36) includes a sub-chamber (42) within the main chamber, the sub-chamber (42) covering the third outlet port (P3), and defining an opening (56) to the main chamber at a forward-most end of the sub-chamber (42).

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.