A gear pump apparatus includes a gear pump and a sealing mechanism which includes an annular rubber member, an outer member, and an inner member. One of the outer member and a casing of the gear pump apparatus has a contact member located outside a portion of the outer member which contacts the gear pump in a radial direction of the gear pump. The contact member is placed to create a physical contact between the outer member and the casing to absorb a part of force by which the outer member is pressed against the gear pump. This results in a decrease in pressure acting on an area of contact between the outer member and the gear pump, which leads to a drop in resistance to sliding between the gear pump and the outer member, thus decreasing a loss of torque required for the pumping operation of the gear pump.

A brake system for hydraulically actuating a pair of front wheel brakes and a pair of rear wheel brakes includes a reservoir and a master cylinder fluidly connected to the reservoir and operable to provide a brake signal. A first power transmission unit is in fluid communication with the reservoir, a selected one of the rear wheel brakes, and a first fluid separator corresponding to a selected one of the front wheel brakes. A first electronic control unit is configured to control the first power transmission unit. A second power transmission unit is in fluid communication with the reservoir, the other one of the front wheel brakes, and a second fluid separator corresponding to an other one of the front wheel brakes. A second electronic control unit is configured to control the second power transmission unit.

A method for braking a vehicle includes at least reducing a hydraulic brake pressure in at least one wheel brake device disposed on a vehicle axle in response to an at least partial failure of a brake boosting of a hydraulic brake with at least one first brake circuit and at least one second brake circuit. The method further includes operating an electric brake motor of an electromechanical braking device to produce a braking force on the at least one wheel brake device.

A vehicle brake system having electronic pressure regulation and a related method, in which the system stabilizes a vehicle, supports the actuation of the brake system, and/or enables a fully/partly automated driving operation. The system has a primary actuator system that sets/regulates different brake pressures at the wheel brakes, and an electronically controllable secondary actuator system that secures the vehicle brake system against primary actuator failure. For a primary actuator error, the secondary actuator is controlled so that the secondary system produces a brake pressure that, based on the dynamic axle load displacement, occurring during a braking process, in the direction of a front axle, is greater than the brake pressure that is convertable into a rear axle wheel brake braking power. A device reduces this brake pressure at the rear axle wheel brake to a value at which the vehicle wheel, assigned to this wheel brake, does not lock.

A method for controlling a hydraulic brake system for a motor vehicle to carry out a braking operation by means of at least one wheel brake includes, in a first step, a pressure buildup in the wheel brake, wherein hydraulic fluid is passed to a wheel brake via a normally open inlet valve. In a second step, a pressure reduction takes place in the wheel brake, wherein hydraulic fluid is discharged from the wheel brake via an energized normally closed outlet valve. The pressure reduction at the wheel brake is accomplished by means of control of the outlet valve in a predefined manner.

A method for operating a regenerative braking system of a vehicle includes: applying control to at least one valve of a brake circuit, before and/or during operation of a generator of the braking system, so that brake fluid is displaced out of a brake master cylinder and/or out of the at least one brake circuit into at least one reservoir volume; defining a target force difference variable regarding a booster force exerted by a brake booster in consideration of at least one of a generator braking torque information item, a brake master cylinder pressure variable, and an evaluation variable derived from at least the generator braking torque information item or the brake master cylinder pressure variable; and controlling the brake booster in consideration of the defined target force difference variable.

A master cylinder includes: an input piston that is caused to advance by operating a brake operating member; a pressure piston that is provided coaxially with the input piston in order to increase a fluid pressure in a frontward pressure chamber while advancing; and a multistage modification device that varies a relationship between a stroke of the input piston and the fluid pressure in the pressure chamber in three or more stages while the input piston moves from a retreat end position to an advancement end position.

A control device, when performing a reallocation control, makes the decrease gradient of regeneration braking force in a first period in which the amount of decrease in a basal fluid pressure from a reference basal fluid pressure is less than a specified amount of decrease greater than the decrease gradient of the regeneration braking force in a second period in which the amount of decrease in the basal fluid pressure is not less than the specified amount of decrease.

A pressure regulator configured to regulate a pressure of a working fluid by two pilot pressures, including: a spool valve mechanism having a spool; a first biasing mechanism configured to bias the spool toward the other end of the pressure regulator in its axial direction by a first pilot pressure in a first-pilot-pressure chamber; a second biasing mechanism configured to bias the spool toward the other end of the pressure regulator by a second pilot pressure in a second-pilot-pressure chamber; and a counter biasing mechanism configured to bias the spool toward one end of the pressure regulator by a pressure of the working fluid in a regulated-pressure chamber, wherein the counter biasing mechanism has a counter biasing piston configured to push the spool toward the one end of the pressure regulator by the pressure of the working fluid in the regulated-pressure chamber applied to the counter biasing piston.

An electro-hydraulic brake system includes a master cylinder (MC) configured to supply fluid into a first MC fluid passageway in response to pressing force on a brake pedal; a pressure supply unit (PSU) assembly having a PSU motor coupled to a ball screw actuator, a PSU housing defining a piston bore having a terminal end opposite the PSU motor, and a PSU piston dividing the piston bore into a first chamber and a second chamber and movable by the ball screw actuator, with each of the first chamber and the second chamber containing a hydraulic fluid; and a backup pump assembly including a pump for supplying the brake fluid to at least one of the wheel brakes. The ball screw actuator includes an actuator nut assembly having a plurality of ball bearings each disposed within the piston bore and submerged in the hydraulic fluid.