Bosch Braking Systems Co. Ltd.

Other

Bosch Automotive Systems Corporation

Yasushi Mori

Hidefumi Inoue

Yoshiyasu Takasaki

Mamoru Sawada

Hiroaki Niino

Kazuya Maki

Hiroyuki Oka

Takasaki Yoshiyasu

Yoshiyuki Hiratsuka

Masakazu Machida

A tubular memberis slidably fitted into a valve body, and is formed with a vacuum valve seat. The tubular member, a valve plungerand the valve bodyare maintained in their inoperative positions shown by abutment against a key member. A holderis formed with a tapered surfaceto assist in allowing an elastic deformation of a reaction disc. Immediately after the commencement of operation of a valve mechanismas an input shaftis driven forward, the input shaftand the tubular memberare maintained in their inoperative positions until a rear end face of a variable pressure passageabuts against the key member. The operating stroke of an input shaftcan be chosen to be less than the operating stroke of an output shaftwhile preventing the jumping value from increasing to an excessively high value.

Negative pressure brake booster

An improvement of a valve plunger used in a brake booster A valve plunger is made up of a rearwardly disposed body and an engaging member mounted on a front portion of the body When a brake pedal is quickly depressed during an emergency brake operation, the engaging member retracts rearward relative to the body whereby the axial size of the entire valve plunger is reduced, thereby increasing the opening of an atmosphere valve during the emergency brake operation as compared with a normal brake operation, allowing an output of an increased magnitude to be rapidly obtained. Thus, the invention allows an output from the brake booster to be rapidly increased in immediate response to a quick depression of a brake pedal.

Brake booster

A first vacuum valve seat is formed on a valve body , and a second vacuum valve seat is formed on a tubular member which is slidably mounted on the valve body . A lever member is provided between the tubular member and a valve plunger , and when the valve plunger strokes through a given stroke or more relative to the valve body , the lever member moves angularly to retract the tubular member rearward relative to the valve body . When a brake pedal is quickly depressed, the lever member moves angularly to cause an engaging tab to engage an engaging recess formed in the valve body , thus retaining the tubular member at a position which is reached as it is retracted rearward relative to the valve body . This allows an atmosphere valve to be opened to a greater opening than during a usual operation, allowing an increased output to be obtained rapidly. The present invention allows an output from a brake booster to be increased rapidly as an immediate response to a quick depression of the brake pedal.

A master cylinder which includes a primary piston and a thrust piston disposed within a housing, and defines an intensifying chamber at a location rearward of the thrust piston. An input shaft has a front end which is disposed within the intensifying chamber. The thrust piston is formed with a communication path (discharge passage), and a control valve is disposed between the thrust piston and the front end of the input shaft to open or close the communication path (discharge passage). When the input shaft is driven forward under the inoperative condition shown and the pump is operated to introduce a discharge pressure from the pump into the intensifying chamber, a liquid pressure is generated in the intensifying chamber and drives the primary piston forward, generating a liquid pressure in a liquid pressure chamber. In this manner, a master cylinder can be provided which has a simple and inexpensive construction with a reduced number of parts and which is compact in size. The master cylinder is capable of providing an increased braking force as required by intensifying a master cylinder pressure.

Master cylinder

Growing community of inventors

Saitama-ken, Japan

Yasushi Mori