Aisin Seiki Kabushiki Kaisha

Yoshihiko Tada

Michiharu Nishii

Genji Mizuno

Yoshihisa Nomura

Kenji Shirai

Masahiko Kato

Junichi Tanoue

Masamoto Ando

A tandem master brake cylinder has first and second pistons, each piston associated with a fluid chamber and a pressure chamber. The pistons are displaced in response to actuation of a brake pedal. A hydraulic booster is coupled to a power source and is operable to enhance the piston movement and for conducting pressurized fluid to a second of the fluid chambers associated with a second piston to displace that piston in a manner reducing the volume of the pressure chamber associated with the first piston. In the event that a negative pressure is communicated with the second fluid chamber, e.g. by a loss of pressurized fluid from the power source, brake fluid is supplied through a one-way check valve to the second fluid chamber to prevent the negative pressure from reversing the motion of the second piston.

Hydraulic brake booster system with check valve in brake fluid reservoir

A hydraulic braking system for controlling the hydraulic pressure of the brake actuator and wheel cylinders includes a dynamic hydraulic pressure control system which transmits boosted hydraulic pressure in response to movement of a brake pedal. A master cylinder receives brake fluid pressure from a reservoir and transmits the fluid pressure from a pressure chamber in the master cylinder to a changeover valve. The changeover valve changes over the connection between wheel cylinders of the vehicle and the dynamic hydraulic pressure control system when the powered pressure which is transmitted from the dynamic hydraulic pressure control system is less than a predetermined pressure. A valve member of the changeover valve is movable between a first and second position so as to transmit the powered hydraulic fluid from the boost pressure chamber to the wheel cylinders of the rear wheels in a first position and block the transmission of the fluid in the second position.

Hydraulic braking system

A hydraulic brake booster is provided which actuates a master cylinder by a hydraulic power pressure supplied from a power source in response to an input rod connected to a brake pedal. The arrangement includes a housing connected to the master cylinder, a power piston slidably disposed in a boost chamber which defined in the housing and transmitting a boost force which is generated in response to the input rod. A hydraulic pressure control valve is provided which has a valve body moved between a power position communicated with the power source and an initial position communicated with a reservoir in the boost chamber on an axis extending substantially in parallel with a sliding axis of the power piston. A control lever engages with the valve body of the hydraulic pressure control valve at its one end and engages with the power piston at its other end. A support lever is pivotally connected with the input rod at one end and a support member installed to the housing pivotally movable and regulating at least the initial position of the valve body of the hydraulic pressure control valve through the one end of the control lever.

Hydraulic brake booster

A pair of spaced apart large-diameter and small-diameter lands between which a fluid chamber is defined are formed on a second piston in a tandem cylinder to which an anti-skid device is added. Booster pressure is applied to the fluid chamber to act on the large-diameter land in a manner fluidly locking the second piston against movement despite a reduction in pressure in the first and second pressure chambers during operation of the anti-skid device. As a result, the movement of the brake pedal in the normal direction of depression is prevented when the anti-skid devices operates.

A hydraulic braking system for an automotive vehicle having a power source for generating a hydraulic power pressure, a reservoir, a master cylinder, a regulator and a plurality of wheel brake cylinders for braking respective road wheels, which are divided into a first group of wheel brake cylinders communicated with the master cylinder and a second group of wheel brake cylinders communicated with the regulator. The regulator has a housing defining therein a regulator chamber for introducing the hydraulic power pressure thereinto from the power source and regulating the hydraulic power pressure into a regulated hydraulic pressure in response to the hydraulic braking pressure generated in the master cylinder, and which is positioned in substantially coaxial relationship with the master cylinder and responsive mechanically to depression of a brake pedal. Accordingly, the regulator normally generates the regulated hydraulic pressure in response to the hydraulic braking pressure generated in the master cylinder, whereas it generates a hydraulic pressure in response to depression of the brake pedal when the hydraulic braking pressure is less than a predetermined value.

Hydraulic braking system for an automotive vehicle

A hydraulic brake system includes a master cylinder for generating a brake fluid pressure in response to a brake pedal, a power fluid source for generating a power fluid pressure by increasing a brake fluid to a predetermined pressure. A dynamic fluid pressure control apparatus supplies the brake fluid pressure to regulate the power fluid pressure from the power fluid pressure source in response to the brake pedal. A plurality of wheel cylinders of each wheel for the vehicle are fluidically communicated with a dynamic fluid pressure control apparatus and the master cylinder via a fluid passage separated into plural control systems. A first changeover valve fluidically and selectively communicates at least one system of the wheel cylinder with one of the dynamic fluid pressure control apparatus and the master cylinder and a control valve disposed in a fluid passage communicates the first changeover valve and the wheel cylinder controls the brake fluid pressure supplied to the wheel cylinder by opening and closing the fluid passage in accordance with the slip state of the wheel upon braking. A control circuit controls the actuation of the control valve and the first changeover valve, and a second changeover valve is disposed in a fluid passage fluidically communicating the first changeover valve and the dynamic fluid pressure control apparatus and selectively communicates the fluid passage with one of the dynamic fluid pressure control apparatus and the power fluid pressure source.

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Hazu, Japan

Yoshihiko Tada