A braking circuit including at least an auxiliary right valve (200) and an auxiliary left valve (300) suitable to allow braking on both sides, right and left of a vehicle, when this is required, but allowing to apply a pressure braking only on one of the two sides, right or left, when this is required to provide a steering function, characterized in that the circuit further comprises a master valve (400) having two positions: a first position when the vehicle has a velocity under a threshold wherein separate and selective right or left braking is authorized and a second position when the vehicle has a velocity above said threshold wherein said master valve (400) connects both a right braking line (204, 1205) and a left braking line (304, 1305) to an output braking line (110) so that if a braking is requested both right braking line (204, 1204) and left braking line (304, 1305) are under pressure and selective right or left braking is forbidden.

A master cylinder includes: a cylinder housing; a piston which is movably disposed in the cylinder housing so as to form a pressure chamber and a hydraulic fluid supplying chamber; a sealing member which is interposed between the cylinder housing and the piston. The piston has a plurality of communication holes for connecting the pressure chamber and the hydraulic fluid supplying chamber, and the plurality of communication holes are formed on a slanted surface which is provided to an outer surface of the piston.

Disclosed herein is an electric brake system including a reservoir, a master cylinder, a hydraulic pressure supply device configured to operate a hydraulic piston according to an electrical signal output in response to a displacement of a brake pedal and generate a hydraulic pressure, a hydraulic pressure control unit configured to control the hydraulic pressure transmitted to a wheel cylinder from the hydraulic pressure supply device, a hydraulic pressure auxiliary device configured to operate when the hydraulic pressure supply device is inoperable and provide the hydraulic pressure to two wheel cylinders and including a pair of pumps configured to pressurize the pressurizing medium, a motor configured to drive the pair of pumps, a first support valve provided on a first auxiliary hydraulic pressure flow path for transmitting the pressurizing medium pressurized by any one of the pair of pumps to a first wheel cylinder to control a flow of the pressurizing medium, and a second support valve provided on a second auxiliary hydraulic pressure flow path for transmitting the pressurizing medium pressurized by the other of the pair of pumps to a second wheel cylinder to control the flow of the pressurizing medium, a pressure sensor configured to detect pressures of the pressurizing media transmitted to the first support valve and the second support valve from the pair of pumps, and a controller configured to control the hydraulic pressure supply device, the hydraulic pressure control unit, and the hydraulic pressure auxiliary device, wherein the controller is configured to estimate a wheel pressure of at least one control target wheel cylinder of the first wheel cylinder and the second wheel cylinder during ABS control in a first fallback mode performed by the hydraulic pressure auxiliary device, synchronize an upstream pressure and a downstream pressure of at least one control target support valve of the first support valve and the second support valve, and compensate the estimated wheel pressure of the control target wheel cylinder to be a pressure detected by the pressure sensor during the synchronization.

Disclosed herein is an electric brake system including a reservoir, a master cylinder, a hydraulic pressure supply device configured to operate a hydraulic piston according to an electrical signal output in response to a displacement of a brake pedal and generate a hydraulic pressure, a hydraulic pressure control unit configured to control the hydraulic pressure transmitted to a wheel cylinder from the hydraulic pressure supply device, a hydraulic pressure auxiliary device configured to operate when the hydraulic pressure supply device is inoperable and provide the hydraulic pressure to two wheel cylinders and including a pair of pumps configured to pressurize the pressurizing medium, a motor configured to drive the pair of pumps, a first support valve provided on a first auxiliary hydraulic pressure flow path for transmitting the pressurizing medium pressurized by any one of the pair of pumps to a first wheel cylinder to control a flow of the pressurizing medium, and a second support valve provided on a second auxiliary hydraulic pressure flow path for transmitting the pressurizing medium pressurized by the other of the pair of pumps to a second wheel cylinder to control the flow of the pressurizing medium, a pressure sensor configured to detect pressures of the pressurizing media transmitted to the first support valve and the second support valve from the pair of pumps, and a controller configured to control the hydraulic pressure supply device, the hydraulic pressure control unit, and the hydraulic pressure auxiliary device, wherein the controller is configured to estimate a wheel pressure of at least one control target wheel cylinder of the first wheel cylinder and the second wheel cylinder during ABS control in a first fallback mode performed by the hydraulic pressure auxiliary device, synchronize an upstream pressure and a downstream pressure of at least one control target support valve of the first support valve and the second support valve, and compensate the estimated wheel pressure of the control target wheel cylinder to be a pressure detected by the pressure sensor during the synchronization.

A valve arrangement is inserted between a master brake cylinder and a reservoir in a housing of an electrohydraulic motor vehicle brake system which can be activated both by a vehicle driver and independently of the vehicle driver. The valve arrangement can be acted on by a volume flow which can be conveyed by a linear actuator in the direction of a pedal travel simulator, the working chamber of the pedal travel simulator being connected to the master brake cylinder, wherein, for the purpose of simplified construction and actuation, the valve arrangement has a hydraulically actuable non-return valve and a fixed orifice arranged parallel to the non-return valve. The non-return valve is arranged together with the fixed orifice in a valve carrier which is fastened to a closure plug which closes the housing of the motor vehicle brake system.

A valve arrangement is inserted between a master brake cylinder and a reservoir in a housing of an electrohydraulic motor vehicle brake system which can be activated both by a vehicle driver and independently of the vehicle driver. The valve arrangement can be acted on by a volume flow which can be conveyed by a linear actuator in the direction of a pedal travel simulator, the working chamber of the pedal travel simulator being connected to the master brake cylinder, wherein, for the purpose of simplified construction and actuation, the valve arrangement has a hydraulically actuable non-return valve and a fixed orifice arranged parallel to the non-return valve. The non-return valve is arranged together with the fixed orifice in a valve carrier which is fastened to a closure plug which closes the housing of the motor vehicle brake system.