| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an improved vacuum type booster device of a simplified constitution capable of making an operation stroke of an input member shorter smoothly than an operation stroke of an output member by a predetermined amount. <P>SOLUTION: In a vacuum type booster device, when the advance of an input member causes an atmosphere valve seat to be separated from an atmosphere valve to advance a power piston, the position of a vacuum valve seat is moved backward relative to the power piston by a distance to which the advance amount of the power piston relative to a housing is decreased at a predetermined ratio. Thus, when the slight advance of the input member causes the atmosphere valve seat to be separated from the atmosphere valve to advance the power piston relative to the housing, the vacuum valve seat is retreated relative to the power piston and advanced by a distance which is obtained by subtracting a retraction amount of the atmosphere valve seat from the advance amount of the power piston relative to the housing, whereby a valve mechanism of this constitution can be closed again accompanied by the advance of the power piston. <P>COPYRIGHT: (C)2007,JPO&INPIT |
