Advics Co., Ltd.

Yoji Inoue

Kaoru Tsubouchi

Yoko Takatori

Yoshiyuki Yasui

Koji Suzuki

Tadashi Terazawa

Satoshi Kawasumi

Katsuhiro Mita

Nobuyuki Hirota

Tomoo Ogura

Tomoyasu Sakai

Minoru Watanabe

Yu Furuta

Masaki Nakagawa

Nan Li

Eri Tanimoto

A check valve of this negative pressure-type booster device is provided with: a cylindrical section that is integrally formed with a shell disposed on one side, communicates with a connection pipe, and is formed in a cylindrical shape protruding toward the inside of a housing; and a valve body section that is disposed inside the cylindrical section, and is axially fitted, within the cylindrical section, to the cylindrical section such that air is permitted to flow from a negative pressure chamber to the connection pipe while the air is prohibited from flowing from the connection pipe to the negative pressure chamber.

Negative-pressure-type booster device

A valve mechanism of this negative pressure type booster device has: a negative pressure valve seat provided on a valve body; an atmospheric valve seat provided on a plunger; and a valve part provided with a negative pressure valve section constituting a negative pressure valve together with the negative pressure valve seat and an atmospheric valve section constituting an atmospheric valve together with the atmospheric valve seat. The valve mechanism is provided with a tilting part which is provided on at least one of the valve body and the valve part and tilts the atmospheric valve section relative to a first plane formed when the negative pressure valve section and the negative pressure valve seat are brought into contact with each other to put the negative pressure valve in a closed state.

Negative pressure-type booster device

A movable diaphragm of a negative pressure type booster device includes an annular rubber diaphragm and an annular metal plate. The diaphragm is airtightly pinched by the housing at an annular outer peripheral bead portion formed at an outer peripheral edge of the diaphragm, and airtightly secured to an outer peripheral portion of a valve body, together with an inner peripheral portion of the plate, at an annular inner peripheral bead portion formed at an inner peripheral edge of the diaphragm. Between the outer peripheral bead portion and the inner peripheral bead portion, there are formed a folded portion having a curved portion toward the front and continuous with the outer peripheral bead portion at an outer peripheral area, and an annular portion continuous with an inner peripheral area of the folded portion and with the inner peripheral bead portion.

Negative pressure type booster device

The present invention provides a vacuum booster, which is constructed such that an area with which a cylinder communicates with a port communicating with a reservoir and being open to the cylinder is reduced at high temperature, so that a sufficient reaction force can be transmitted from a piston of a master cylinder to a valve mechanism at an initial stage of the braking operation, thus preventing vibration or noise from being generated in the valve mechanism. At high temperature, stop position, at which backward movement of the piston of the master cylinder is limited by an output member while a valve piston is at a non-operating position, is shifted forwards by a stop position shifting means, thus reducing the area with which the cylinder communicates with the port communicating with the reservoir and being open to the cylinder. At low temperature, while the valve piston is at the non-operating position, the stop position of the piston is not shifted, thus maintaining the area wide, with which the port communicates with the cylinder.

Vacuum booster of brake device

A valve pistonof a vacuum type booster device is provided with a bypass passagewhich is defined between a sound-absorbing memberand an input rodto communicate directly with the atmosphere and a sliding-type plate valvecomposed of three plate valve partswhich are arranged around the input rodto be relatively slidable in radial directions. When the input rodis advanced beyond a predetermined distance relative to the valve piston, the sliding-type plate valveis separated between two of the plate valve partsto make the bypass passagecommunicate with the inside of the valve piston

Vacuum type booster device

In a negative pressure type booster device, secondary passagescommunicating directly with the atmosphere is formed between the internal surface of a sliding cylindrical portionof a valve pistonand the external surface of a silencer, and communication meansis provided for being controlled to vary its path area in dependence on the advance amount of an input rodwhen the same is moved beyond a predetermined distance relative to the valve piston. Thus, when a brake pedalis stepped on strongly, the atmospheric air can be led from the secondary passagesthrough the communication meansto a variable pressure chamber, so that the property of the responsiveness in braking operation can be improved to a responsiveness enhancing property which varies in dependence on the manner of stepping the brake pedal

A master cylinder includes a cylinder body, primary cups supported on the inner periphery of the cylinder body, and a primary piston and a secondary piston inserted in the cylinder body so as to be in sliding contact with the respective primary cups. The cylinder body is integrally formed with annular walls behind the respective primary cups. The annular walls have a greater inner diameter than the inner diameter of the cylinder body to define annular passages between the annular walls and the respective pistons. Connecting passages having a greater radial dimension than the annular passage are defined between the inner periphery of the cylinder body and the respective pistons behind the respective annular walls so as to communicate with a reservoir. While the master cylinder is not actuated, piston ports formed in the respective pistons communicate with the reservoir through the respective annular passages and connecting passages. Brake fluid can thus be sucked smoothly into the respective pressure chambers both during a return stroke of the pistons and during automatic brake control such as vehicle stability control.

Master cylinder

A brake hydraulic pressure generator is proposed which is simple in structure and can suppress fluctuations in the brake pedal operating amount due to fluctuations in the amount of brake fluid consumed in the brake circuit. The brake hydraulic pressure generator includes an input shaft operated by a brake pedal, a stroke simulator for imparting a stroke and a reaction force corresponding to the brake pedal operating amount to the input shaft, a master cylinder for generating brake hydraulic pressure, and a pressure detector member for applying a reaction force corresponding to the hydraulic pressure in the master cylinder to a valve member of the control valve. The reaction force is transmitted through the pressure detector member to the control member. The input to the brake pedal is transmitted to the control valve through the stroke simulator so as to oppose the reaction force. The control valve operates to balance the reaction force and the input.

Vehicle brake hydraulic pressure generator

A negative pressure type booster includes a power piston, a slide valve, and a holding mechanism, among others, and assists a driver during emergency braking. The holding mechanism is adapted to hold the slide valve at a predetermined frontward position, and includes a latch member that is mounted to the power piston in such a manner as to be linearly movable in a radial direction, and a garter spring for biasing the latch member radially inward. The latch member has a hook that can be engaged with and disengaged from a hook provided on the slide valve. When a plunger moves frontward relative to the power piston by a quantity greater than a predetermined value, a push slope provided on the plunger pushes a passive slope provided on the latch member radially outward, whereby the hook of the latch member is disengaged from the hook of the slide valve.

Negative pressure type booster

In a negative pressure type booster, an atmospheric valve seat is formed on an annular disk of an input member, which disk extends radially outward. The annular disk and an annular diaphragm located frontward of the annular disk and mounted to the input member define an annular atmospheric chamber. The atmospheric chamber communicates with the atmosphere via an air hole formed in the annular disk. The diaphragm is supported from the front by a power piston. The diaphragm is a flexible member. Inner and outer circumferential portions of the flexible member are formed into respective rolling portions for allowing frontward/rearward movement of the input member by means of curviform deformation. An atmospheric control valve portion, which is seated on and separated from the atmospheric valve seat, and a vacuum control valve portion, which is seated on and separated from a vacuum valve seat formed on the power piston, are axially separated.

A brake booster device for use in a brake system of vehicles is provided with a partition member dividing the interior of the booster shell into front and rear chambers and a piston movable bodily with the partition member within the booster shell. A control valve body is carried on the piston to move toward and away from the rear surface of the piston through a predetermined amount. An air valve member is received within the piston for relative movement thereto and is urged by a compression spring to be moved rearwardly. When the brake pedal is stepped on, the air valve member is forwardly moved by an input rod relative to the piston, whereby the control valve member leads the atmospheric pressure to the rear chamber thereby to move the partition member and the piston forwardly from a home position. When the brake pedal is released, on the contrary, the control valve leads a negative pressure from the front chamber to the rear chamber thereby to permit the partition member and the piston to move rearwardly to the home position by the force of a return spring. The movement of the piston operates a master cylinder through an output rod to generate braking power.

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Toyoake, Japan

Yoji Inoue