A master cylinder for a hydraulic brake comprises a compensating chamber, a cylinder in which a piston is movably disposed, a pressure chamber disposed in the cylinder and connected to the compensating chamber through at least one connecting opening, and a gasket for interrupting the connection between the pressure chamber and the compensating chamber. The gasket seals the compensating chamber and the pressure chamber against the environment.

A master cylinder includes a piston seal installed in a circumferential groove. The piston seal includes an annular base section, an inner circumferential lip section protruding from an inner circumferential side of the base section to come in sliding contact with an outer circumferential surface of a piston, an outer circumferential lip section protruding from an outer circumferential side of the base section to abut the circumferential groove, and an intermediate protrusion section protruding from between the inner circumferential lip section and the outer circumferential lip section of the base section to a forward side of the outer circumferential lip section. A step difference section is formed at the outer circumferential side. The circumferential groove has a step section that always abuts an outer circumferential surface of the step difference section. A communication path configured to bring a supply path that is in communication with a reservoir and the bottom section side of the circumferential groove in communication with each other is formed between the step difference section and the step section.

A master cylinder includes a piston seal installed in a circumferential groove. The piston seal includes an annular base section, an inner circumferential lip section protruding from an inner circumferential side of the base section to come in sliding contact with an outer circumferential surface of a piston, an outer circumferential lip section protruding from an outer circumferential side of the base section to abut the circumferential groove, and an intermediate protrusion section protruding from between the inner circumferential lip section and the outer circumferential lip section of the base section to a forward side of the outer circumferential lip section. A step difference section is formed at the outer circumferential side. The circumferential groove has a step section that always abuts an outer circumferential surface of the step difference section. A communication path configured to bring a supply path that is in communication with a reservoir and the bottom section side of the circumferential groove in communication with each other is formed between the step difference section and the step section.

Disclosed herein is a master cylinder for a brake system. The master cylinder for a brake system comprises a cylinder body in which a bore is formed, at least one piston provided to be movable forward and backward in the bore, a hydraulic chamber pressurized by the piston, an oil port connected to a reservoir and configured to supply oil to the hydraulic chamber of the cylinder body, and a sealing member installed in the cylinder body and configured to block a flow of oil between the oil port and the hydraulic chamber according to a movement of the piston, wherein the piston includes a piston groove having an inclined surface in contact with the sealing member and a plurality of piston holes formed along an outer circumferential surface of the piston groove configured to communicate the oil port with the hydraulic chamber.

Disclosed herein is a master cylinder for a brake system. The master cylinder for a brake system comprises a cylinder body in which a bore is formed, at least one piston provided to be movable forward and backward in the bore, a hydraulic chamber pressurized by the piston, an oil port connected to a reservoir and configured to supply oil to the hydraulic chamber of the cylinder body, and a sealing member installed in the cylinder body and configured to block a flow of oil between the oil port and the hydraulic chamber according to a movement of the piston, wherein the piston includes a piston groove having an inclined surface in contact with the sealing member and a plurality of piston holes formed along an outer circumferential surface of the piston groove configured to communicate the oil port with the hydraulic chamber.

A method for diagnosing an electric brake system is disclosed. The method for diagnosing an electric brake system, which includes a reservoir, a master cylinder, a first backup flow path, a second backup flow path, a first cut valve, a second cut, a simulation device, a hydraulic pressure supply device, a first hydraulic flow path, a second hydraulic flow path, a hydraulic control unit, and an electronic control unit configured to control the hydraulic pressure supply device and the valves on the basis of hydraulic pressure information and displacement information of the brake pedal, comprising a first diagnosis mode of: closing the first cut valve and the second cut valve when the pedal effort is not provided to the brake pedal; operating the hydraulic pressure supply device to generate hydraulic pressure at the hydraulic control unit; measuring the hydraulic pressure in the first or second hydraulic circuit; and comparing the measured hydraulic pressure with a first reference pressure to diagnose abnormality of the valves.

A method for diagnosing an electric brake system is disclosed. The method for diagnosing an electric brake system, which includes a reservoir, a master cylinder, a first backup flow path, a second backup flow path, a first cut valve, a second cut, a simulation device, a hydraulic pressure supply device, a first hydraulic flow path, a second hydraulic flow path, a hydraulic control unit, and an electronic control unit configured to control the hydraulic pressure supply device and the valves on the basis of hydraulic pressure information and displacement information of the brake pedal, comprising a first diagnosis mode of: closing the first cut valve and the second cut valve when the pedal effort is not provided to the brake pedal; operating the hydraulic pressure supply device to generate hydraulic pressure at the hydraulic control unit; measuring the hydraulic pressure in the first or second hydraulic circuit; and comparing the measured hydraulic pressure with a first reference pressure to diagnose abnormality of the valves.

A hydraulic block of a slip regulation of a hydraulic vehicle power brake system that has a master brake cylinder bore and forms a master brake cylinder. In order to prevent a hard impact of a piston of the master brake cylinder against an end stop when the master brake cylinder is released, in particular when there is an abrupt release, for example when the foot slides off a foot brake pedal, a hydraulic return damper that is integrated in the piston is provided.

An electric brake system is disclosed. The electric brake system comprises an electronic control unit configured to control a hydraulic pressure supply device and valves on the basis of hydraulic pressure information and pedal displacement information and including a circuit board on which a plurality of electronic elements are mounted, and the hydraulic pressure supply device configured to generate hydraulic pressure using a rotational force of a motor that is activated in response to an electrical signal output from the electronic control unit, wherein the circuit board and a housing of the hydraulic pressure supply device contact each other to transfer heat generated at the plurality of electronic elements to the housing of the hydraulic pressure supply device.

An electric brake system is disclosed. The electric brake system comprises an electronic control unit configured to control a hydraulic pressure supply device and valves on the basis of hydraulic pressure information and pedal displacement information and including a circuit board on which a plurality of electronic elements are mounted, and the hydraulic pressure supply device configured to generate hydraulic pressure using a rotational force of a motor that is activated in response to an electrical signal output from the electronic control unit, wherein the circuit board and a housing of the hydraulic pressure supply device contact each other to transfer heat generated at the plurality of electronic elements to the housing of the hydraulic pressure supply device.