| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve the durability of a negative pressure type booster which is of simple and compact structure while having a stable threshold at the time of emergency brake characteristics is obtained. <P>SOLUTION: A holding mechanism retaining a slide valve 60 at a predetermined position in the front is equipped with a locking member 64 fitted on a power piston 30 in a manner linearly movable in the direction of its diameter, and a garter spring 65 that biases the locking member 64 toward the inside of the diameter. The locking member 64 has a locking side hook 64a which can be engaged with/disengaged from a valve side hook 60b of the slide valve 60 while constituting the holding mechanism together with the garter spring 65 and the like. The power piston 30 is provided with a lock mechanism (stopper 66 and spring 67) that fixes the locking member 64 releasably at an initial position. This regulates the locking member 64 at the initial position from moving outward from its diameter direction when a vehicle is at rest and a brake operation is performed that causes the advancement amount of an input member 40 against the power piston 30 to come to be greater than a predetermined value. <P>COPYRIGHT: (C)2012,JPO&INPIT |
