A master brake cylinder for a braking system of a vehicle is described, having a first pressure chamber. A first rod piston element is movable into at least a first partial pressure chamber of the first pressure chamber in such a way that a first partial residual volume of the first partial pressure chamber which is fillable with liquid is reducible by moving the first rod piston element. The master brake cylinder also includes a second partial pressure chamber of the first pressure chamber which is delimited from the first partial pressure chamber via at least one partial partition and into which a second rod piston element is movable in such a way that a second partial residual volume of the second partial pressure chamber which is fillable with liquid is reducible by moving the second rod piston element. Moreover, a manufacturing method is described for a master brake cylinder.

A master brake cylinder for a braking system of a vehicle is described, having a first pressure chamber. A first rod piston element is movable into at least a first partial pressure chamber of the first pressure chamber in such a way that a first partial residual volume of the first partial pressure chamber which is fillable with liquid is reducible by moving the first rod piston element. The master brake cylinder also includes a second partial pressure chamber of the first pressure chamber which is delimited from the first partial pressure chamber via at least one partial partition and into which a second rod piston element is movable in such a way that a second partial residual volume of the second partial pressure chamber which is fillable with liquid is reducible by moving the second rod piston element. Moreover, a manufacturing method is described for a master brake cylinder.

A master cylinder apparatus includes: an input piston that can be moved forward by operating a brake operating member; a pressure piston provided in front of the input piston to be capable of moving relative to the input piston; and a stroke velocity ratio modification device capable of modifying a stroke velocity ratio, which is a ratio between a stroke velocity of the pressure piston and a stroke velocity of the input piston, in at least two stages within a range not greater than a predetermined value larger than 1.

A master cylinder apparatus includes: an input piston that can be moved forward by operating a brake operating member; a pressure piston provided in front of the input piston to be capable of moving relative to the input piston; and a stroke velocity ratio modification device capable of modifying a stroke velocity ratio, which is a ratio between a stroke velocity of the pressure piston and a stroke velocity of the input piston, in at least two stages within a range not greater than a predetermined value larger than 1.

The invention relates to an electrically controllable pressure provision device (5, 5), particularly for a hydraulic motor-vehicle brake system, comprising a stepped bore (54), which is arranged in a housing (53,21), and a piston (51), which can be actuated by an electromechanical actuator (35, 36). The piston (51), together with the housing (53, 21), delimits a pressure chamber (50). The piston (51) is constructed as a stepped piston, the smaller-diameter piston step (51) of which enters the smaller-diameter step (54) of the stepped bore after a specified actuation of the stepped piston, such that the pressure chamber (50) is subdivided into a first pressure chamber (55) and a second pressure chamber (56). The invention further relates to a brake system for motor vehicles having such a pressure provision device.

The invention relates to an electrically controllable pressure provision device (5, 5), particularly for a hydraulic motor-vehicle brake system, comprising a stepped bore (54), which is arranged in a housing (53,21), and a piston (51), which can be actuated by an electromechanical actuator (35, 36). The piston (51), together with the housing (53, 21), delimits a pressure chamber (50). The piston (51) is constructed as a stepped piston, the smaller-diameter piston step (51) of which enters the smaller-diameter step (54) of the stepped bore after a specified actuation of the stepped piston, such that the pressure chamber (50) is subdivided into a first pressure chamber (55) and a second pressure chamber (56). The invention further relates to a brake system for motor vehicles having such a pressure provision device.

An input piston connected to a brake pedal and an output piston which is moved forward to increase a hydraulic pressure in a pressure chamber are fitted to each other telescopically, and an engaging spring is provided between the input piston and the pressure chamber. The output piston is moved forward relative to the input piston by a hydraulic pressure in a rear chamber while compressing the engaging spring. Since a set load of the engaging spring is set at a small value, the output piston is moved forward relative to the input piston in an initial period of a braking operation, making it possible to reduce a stroke of the input piston which is required for a hydraulic pressure in brake cylinders to reach a first set pressure.

An input piston connected to a brake pedal and an output piston which is moved forward to increase a hydraulic pressure in a pressure chamber are fitted to each other telescopically, and an engaging spring is provided between the input piston and the pressure chamber. The output piston is moved forward relative to the input piston by a hydraulic pressure in a rear chamber while compressing the engaging spring. Since a set load of the engaging spring is set at a small value, the output piston is moved forward relative to the input piston in an initial period of a braking operation, making it possible to reduce a stroke of the input piston which is required for a hydraulic pressure in brake cylinders to reach a first set pressure.

A vehicle braking system includes a master cylinder having a pedal feel simulator incorporated therein, a reservoir configured to retain a volume of unpressurized brake fluid for use in the vehicle braking system, a wheel cylinder coupled to the master cylinder via a first braking circuit, an electronically-controlled pressure generating unit configured to move fluid through the first braking circuit to the wheel cylinder in a first mode of operation, and a two-way valve positioned in the first braking circuit and configured to selectively decouple the master cylinder from the wheel cylinder. In the first mode of operation, the master cylinder is decoupled from the wheel cylinder via the two-way valve and the master cylinder is coupled to the reservoir via the two-way valve. In a second mode of operation, the master cylinder is coupled to the wheel cylinder via the two-way valve.

A vehicle braking system includes a master cylinder having a pedal feel simulator incorporated therein, a reservoir configured to retain a volume of unpressurized brake fluid for use in the vehicle braking system, a wheel cylinder coupled to the master cylinder via a first braking circuit, an electronically-controlled pressure generating unit configured to move fluid through the first braking circuit to the wheel cylinder in a first mode of operation, and a two-way valve positioned in the first braking circuit and configured to selectively decouple the master cylinder from the wheel cylinder. In the first mode of operation, the master cylinder is decoupled from the wheel cylinder via the two-way valve and the master cylinder is coupled to the reservoir via the two-way valve. In a second mode of operation, the master cylinder is coupled to the wheel cylinder via the two-way valve.