Patent ID: 7207261
Filing Date: 2007-04-24
Classification: B60T

Abstract:
1. A vacuum-operated booster comprising: a housing; a movable diaphragm dividing the interior of the housing into a constant-pressure chamber and a variable-pressure chamber; a valve body connected to the movable diaphragm and having an axial hole; a valve mechanism built in the axial hole and including an input shaft axially movable with respect to the valve body, a plunger connected to a front end portion of the input shaft, and a valve seat provided at a rear end portion of the plunger; a reaction member which is disposed in the axial hole to be axially movable with respect to the valve body and with which a front end portion of the plunger is engageable; an output shaft which is disposed in the axial hole to be axially movable and which comes into engagement, at its rear end portion, with a front face of the reaction member, an output being generated at the output shaft when an input is applied to the input shaft; and a reaction force dividing mechanism for transmitting reaction force of the output from a rear face of the reaction member to the valve body and the plunger, wherein the reaction force dividing mechanism transmits all the reaction force of the output of the output shaft only to the plunger in a low-load servo region in which the output of the output shaft is equal to or less than a set value, and transmits the reaction force to the valve body and the plunger while dividing the reaction force therebetween at a set ratio in a high-load servo region in which the output of the output shaft is greater than the set value.