A method for providing a brake force in a vehicle with a hydraulic vehicle brake and an electromechanical brake device includes determining a position of a brake piston at a brake contact point on the basis of a state variable of an electric brake motor when the electromechanical brake device is released. The method further includes displacing the brake piston in a positioning operation until reaching a braking start point.

The present invention relates to a brake system for a vehicle. The proposed brake system (1) comprises an actuation unit for actuating wheel brakes of the vehicle in a normal operating mode of the brake system (1). Further, the system (1) comprises a brake cylinder (2) for pressurizing the wheel brakes of the vehicle in an emergency operating mode of the brake system (1). The brake cylinder (2) comprises a brake cylinder housing (4) and a push rod (3) being displaceable within the brake cylinder housing (4) by operation of a brake pedal (5). The brake cylinder (2) further comprises a piston (14) movably arranged within the brake cylinder housing (4). The piston (14) has a first surface and a second surface opposite the first surface. A hydraulic chamber (11) is formed within the brake cylinder housing (4) between the first surface of the piston (14) and an inner surface of the brake cylinder housing (4). The hydraulic chamber (11) is configured for being selectively fluidly connected with the wheel brakes. The brake cylinder (2) further comprises an elastic simulator element (13) arranged between the second surface of the piston (14) and the push rod (3) for pedal feel simulation. The brake cylinder (2) further comprises a locking element (22) configured to selectively mechanically couple the push rod (3) with the piston (14) to provide a rigid connection between the push rod (3) and the piston (14) during the emergency operating mode.

A friction brake system comprises a first gear unit having a first member and a second member, the first gear unit is configured for converting a rotary motion of the first member into a braking motion of the second member, the first member is configured such that the rotary motion may be driven by an electric motor, the brake system further comprises a second gear unit having a spindle and nut for converting a rotary motion into a linear motion for pad wear compensation, the spindle is connectable to a brake pad, the second member of the first gear unit and the nut of the second gear unit are or may be mechanically coupled such that, during the braking motion, the second member of the first gear unit pushes against the nut of the second gear unit to press the brake pad against a friction surface.

A control valve for applying a spring-loaded brake pressure to spring-loaded parts of a rear-axle wheel brake is pneumatically activated as a function of a parking-brake braking demand and a service-brake braking demand. A first control chamber is connected via a first control piston to a control arrangement in the control valve. During an adjustment of the first control chamber via the service-brake control pressure, the spring-loaded brake pressure at the working output is a function of the service-brake control pressure or of the parking-brake control pressure. The first control piston is connected to a third control chamber, wherein the pressure in the first control chamber acts on the first control piston in one direction, and the pressure in the third control chamber acts on the first control piston in the opposite direction. The first control chamber is selectively connectable to the third control chamber via a switchable bypass valve.

A method for operating a hydraulic brake system of a motor vehicle includes generating a force for displacing a brake piston of a wheel brake of the brake system for the actuation thereof via a pressure generator and an electromechanical actuator of the brake system. The method further includes actuating one or more of the pressure generator and the actuator to set a parking brake function and monitoring the operability of the brake system. The method further includes monitoring the actuator for a change of the operating state thereof, and suspending the monitoring for a specifiable period of time depending on a detected change.

An apparatus for operating an electric parking brake of a vehicle includes a generator and a control device. The generator is designed to provide energy for supplying the electric parking brake of the vehicle with energy, and the control device is designed to activate the generator for supplying the electric parking brake with energy depending on a result of a monitoring of an energy supply to the electric parking brake.

A method is used for checking the braking force in a vehicle, which has a hydraulic vehicle brake having a brake booster and an electromechanical brake device having a brake motor. In order to build up a braking force, first of all the brake booster is activated, and subsequently an electromechanical braking force is generated by application of the brake motor. If a pressure drop occurring in the brake fluid is outside a permissible value range, a fault signal is generated.

A brake control device according to an embodiment executes, for an electric braking wheel of either the front wheel and the rear wheel, a brake hold control for driving an electric braking device to move a propulsion shaft toward the braked member to be braked and bring it into contact with a piston, calculating a target braking force for maintaining the stationary state of the vehicle, subtracting first braking force from the target braking force to calculate a required hydraulic braking force applied to the non-electric braking wheel different from the electric braking wheel, and controlling a differential pressure control valve connected to the non-electric braking wheel of the hydraulic braking device so that the required hydraulic braking force is applied to the non-electric braking wheel.

A twin piston caliper with an electric parking brake and method of operating such a twin piston caliper with an electric parking brake. The twin piston caliper housing comprises two separate inner brake pads for each of the two pistons; one outer brake pad at the outer housing finger area; an electric parking brake mechanism configured to be incorporated in between the two pistons so that it is not embedded in the hydraulic piston and not the hydraulic brake fluid; and wherein the electric parking brake mechanism uses its own electric parking brake friction brake pad to clamp against the brake rotor. The method of operating the twin piston caliper with the electric parking brake comprising the following steps: using hydraulic pressure, preferably high pressure overlay, to clamp up inner brake pads and the outer brake pad against a brake rotor; applying the electric parking brake mechanism to clamp an electric parking brake friction brake pad against the brake rotor; releasing the hydraulic pressure to unclamp the two inner brake pads whereby the electric parking brake mechanism maintains the clamp between the outer brake pad and the electric parking brake friction brake pad.

A pedal-travel simulator of a hydraulic power vehicle brake system is connected to a brake-fluid reservoir by way of a groove between two piston seals of a power brake-pressure generator. Any air bubbles in the brake fluid get out of the pedal-travel simulator into the brake-fluid reservoir, and the piston seals are lubricated with the brake fluid.