| 摘要 |
PROBLEM TO BE SOLVED: To provide a negative pressure type booster capable of switching from a normal brake characteristic to an emergency brake characteristic by a simple and inexpensive mechanism. SOLUTION: This negative pressure type booster comprises an engagement releases means for releasing the engagement of an engagement part 52 with a valve seat member 40 when the amount of relative movement of an input member 37 to a power piston 22 in the axial direction is equal to or more than a specified value. The engagement release means further comprises a distance reducing means to reduce a distance between the input member 37 and the engagement member when a force applied to the input member 37 is equal to or more than a specified value. |
