A piston-cylinder unit includes a piston delimiting at least one working chamber, in which a first seal for sealing at least one first working chamber is arranged either between the piston and cylinder or between a plunger connected to the piston and the cylinder. A second seal is arranged between the first seal and the first working chamber, and the piston-cylinder unit further includes a first channel arranged in the wall of the cylinder or in the piston, which joins the first seal and the second seal in the inner chamber of the cylinder. The first channel and/or a hydraulic line connected thereto may have a throttle device and/or a valve device. An electronic control and regulating device may have a diagnosis or monitoring function for a possible defect or failure of a seal. Multiple hydraulic devices may have such piston-cylinder units and respective control and such regulating devices.

A hydraulic block of an electronic braking device for a vehicle may include: a block body; an input port part disposed on the block body, and connected to an output line of a main braking device to brake a vehicle using hydraulic pressure; an output port part connected to a hydraulic brake line for individually adjusting one or more wheels; and a hydraulic circuit part formed in the block body so as to extend from the input port part to the output port part, and configured to control hydraulic pressure for redundancy of vehicle braking.

A hydraulic block of an electronic braking device for a vehicle may include: a block body; an input port part disposed on the block body, and connected to an output line of a main braking device to brake a vehicle using hydraulic pressure; an output port part connected to a hydraulic brake line for individually adjusting one or more wheels; and a hydraulic circuit part formed in the block body so as to extend from the input port part to the output port part, and configured to control hydraulic pressure for redundancy of vehicle braking.

A parking brake for a wheel rotor having a brake pad associated therewith includes a housing defining first and second passages. First and second pistons are provided in the respective first and second passages. Spindles are threadably connected with each piston. A clutch unit is connected to the spindles. The clutch unit has a first condition allowing relative rotation between the spindles and the pistons such that the pistons are axially movable within the passages and into engagement with the brake pad in response to hydraulic pressure applied to the pistons. The clutch unit has a second condition preventing relative rotation between the spindles and the pistons such that pistons remains engaged with the brake pad when hydraulic fluid pressure is removed from the pistons.

A parking brake for a wheel rotor having a brake pad associated therewith includes a housing defining first and second passages. First and second pistons are provided in the respective first and second passages. Spindles are threadably connected with each piston. A clutch unit is connected to the spindles. The clutch unit has a first condition allowing relative rotation between the spindles and the pistons such that the pistons are axially movable within the passages and into engagement with the brake pad in response to hydraulic pressure applied to the pistons. The clutch unit has a second condition preventing relative rotation between the spindles and the pistons such that pistons remains engaged with the brake pad when hydraulic fluid pressure is removed from the pistons.

A method for controlling vehicle braking of a wheel rotor having a brake pad associated therewith includes moving a piston into engagement with the brake pad by applying hydraulic pressure to the piston. The piston is locked in place against the brake pad with a parking brake. The hydraulic pressure is removed from the piston while the parking brake is locked.

A method for controlling vehicle braking of a wheel rotor having a brake pad associated therewith includes moving a piston into engagement with the brake pad by applying hydraulic pressure to the piston. The piston is locked in place against the brake pad with a parking brake. The hydraulic pressure is removed from the piston while the parking brake is locked.

The present disclosure provides an electronic hydraulic brake system that can appropriately provide redundancy braking force, that is, an electronic hydraulic brake system that provides a so-called redundancy function, in the situation in which a driver does not drive or gives less attention to driving such as autonomous driving or smart cruise control and a main braking device malfunctions.

The present disclosure provides an electronic hydraulic brake system that can appropriately provide redundancy braking force, that is, an electronic hydraulic brake system that provides a so-called redundancy function, in the situation in which a driver does not drive or gives less attention to driving such as autonomous driving or smart cruise control and a main braking device malfunctions.

A brake system may include an actuation device, in particular a brake pedal; a first piston-cylinder unit with two pistons, in particular an auxiliary piston and a second piston, in order to supply brake circuits with a pressure medium via a valve device, wherein one of the pistons, in particular the auxiliary piston, can be actuated by means of the actuation device; a second piston-cylinder unit comprising an electric motor-powered drive, a transmission, and at least one piston in order to supply pressure medium to at least one of the brake circuits via a valve device; and a motor pump unit with a valve device in order to supply pressure medium to the brake circuits. The brake system may further include a hydraulic travel simulator which is connected to a pressure or working chamber of the first piston-cylinder unit.