| 摘要 |
<P>PROBLEM TO BE SOLVED: To smoothly flex a bellows of a boot to follow a valve piston even at a rapid actuation time of a brake. <P>SOLUTION: A boot 26 is provided to which a bellows 26b shrinkable in an axial direction for covering a valve piston 8 is formed, and one end of the boot is engaged with a booster shell 1. The other end of the boot is fitted with an annular groove 23a formed on an input member 20, and a ventilation hole 26c for introducing the atomosphere to an atmosphere valve 31b is formed at a plane part 26a of the boot fitted with the annular groove so as to heighten the rigidity of a plane part of the boot and a bending part 26b1 bent in the direction of the bellows from the plane part. <P>COPYRIGHT: (C)2007,JPO&INPIT |
