Abstract: 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.

Abstract: 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.

Abstract: A vehicle brake booster apparatus includes a housing and a power piston positioned within the interior of the housing to divide the interior into a first pressure chamber and a second pressure chamber, with the power piston being movable in response to a pressure difference between the second pressure chamber and the first pressure chamber. An axially movable input rod extends outwardly from the power piston and is adapted to be operatively connected to a brake pedal. An axially movable output rod extends outwardly from the housing and is adapted to be operatively connected to a master cylinder. An axially movable valve plunger is mounted within the power piston and is operatively connected to the input rod. A control valve is disposed within the power piston and controls the pressure difference between the first pressure chamber and the second pressure chamber.

Abstract: A tandem vacuum servo unit includes a movable power piston having a supporting portion and a front movable wall member having a first engaging portion for engaging the movable power piston. The first engaging portion has an input side face that engages the output side face of the supporting portion along a first contacting portion. A rear movable wall member has a second engaging portion whose input side face engages the output side face of the first engaging portion along a second contacting portion. The first contacting portion is spaced radially outwardly of the second contacting portion. This construction of the vacuum servo unit increases the durability of the front movable wall member.

Abstract: A vacuum type brake booster includes a housing including a front shell and a rear shell in which a constant negative pressure chamber and a variable pressure chamber are defined by a power piston and a diaphragm, a partition for dividing the variable pressure chamber into a first variable chamber next to the constant negative pressure chamber and a second variable chamber, a normally opened valve mounted on the partition for establishing or interrupting of the fluid communication an output rod movable together with the power piston, an input rod for urging the output rod, a valve mechanism disposed with in the power piston to be operated by the input rod and used for controlling the differential pressure between the constant negative pressure chamber and the variable pressure chamber by controlling the fluid communication of the second variable chamber with the constant negative pressure chamber and the atmosphere and a normally closed valve mounted on a rear shell and the partition and disposed between the f

Abstract: A vacuum brake booster includes a secured arrangement for securing a flange portion of a control valve element to a cylindrical portion of the power piston so as to prevent relative movement between the flange portion of the control valve element and the power piston. Thereby, the seal surface of the control valve element is not urged toward the valve seat of the power piston by a pressure differential applied to the flange portion. The urging force of a second coil spring arrangement which urges the control valve element to separate from the valve seat in the non-operating condition of the vacuum brake booster is positively decreased without exerting an adverse influence to the control of the braking force of the vacuum brake booster (10). Accordingly, the input load of the vacuum brake booster is decreased and the operational feeling of the braking action is improved.

Abstract: A brake booster includes a housing in which a constant-pressure chamber and a variable-pressure chamber are defined by a power piston. An input rod is operatively connected to one end of the power piston and receives an input force. A valve is provided in the power piston and operatively connected to the input piston so as to open upon receipt of the input force in such a manner that the differential pressure between the chambers moves the power piston. An output rod is operatively connected to the other end of the power piston. A wall member is provided across which a first auxiliary chamber at a side of the variable-pressure chamber and a second auxiliary chamber formed at a slide of the constant pressure are formed. An orifice passage connects the variable pressure chamber and the first auxiliary chamber.

Abstract: A booster, for use as an automotive brake booster is disclosed which works quickly at the beginning of an operation sequence. The booster has a housing with a piston capable of sliding in the opening of the housing and acting on a diaphragm dividing the inside of the housing into a constant pressure chamber and a variable pressure chamber. An output rod is provided having a rear end portion inserted in the power piston. A reaction disk is mounted between the output rod and the power piston with a retainer mounted on the power piston on the side of the constant pressure chamber. The retainer prevents the output rod from coming off and also causes the output rod to push the reaction plate toward the piston.

Abstract: A vacuum booster comprising a push rod, a housing including a front and rear shells connected with each other, a power piston located in the housing and dividing an interior of the housing into a constant pressure chamber and a variable pressure chamber with a diaphragm, a valve plunger located within the power piston and a control valve member located in the power piston. The power piston has a valve seat contactable with the control valve, and the seat surface of the valve plunger is separable from the control valve member. The seat surface of the valve plunger includes a circular spherical seat surface, and a seal surface of the control valve member contacted with the seat surface includes a concave spherical seat surface which the seat surface of the valve plunger touches internally.

Abstract: A vacuum booster including a push rod, a housing having a first and second compartments, a power piston located in the housing and operated by a pressure differential between the first and second compartments and including a small and large diameter opening portion, a control valve operatively associated with the push rod and located within the power piston for controlling the pressure differential between the first and second compartments in response to movement of the push rod, an output member having a rear end portion slidably disposed within the large diameter opening portion of the power piston, a valve plunger provided in the control valve and having one end slidably disposed in the small diameter opening of the power piston, a resilient reaction disc located adjacent the rear end portion of the output member and disposed within the large diameter portion of the power piston, and an elastic member disposed between the rear end portion of the output member and the power piston and defining a position of