| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve assemblability of a cover member attached to a valve piston (or a movable partition wall) in a negative pressure chamber. <P>SOLUTION: The vacuum type booster includes a movable partition wall 20 and a valve piston 30 attached to a housing 10, an input member 40, an output member 50, a reaction force member 60, a control valve 70, and a key member 80 which are attached to the valve piston 30. The vacuum type booster further includes a negative pressure passage (30h) formed in the valve piston 30 and normally communicated with a negative pressure chamber R1, and a plate-shaped cover member 32 having a communicating path P1 attached to the valve piston 30 in the negative pressure chamber R1 for covering a front end opening of the negative pressure passage (30h) and communicating the front end opening with the negative pressure chamber R1. The cover member 32 includes a circular plate 32a abutting on a front end portion of the valve piston 30, and a covered portion 32b having a shape for forming the communication path P1 even when placed at the position where brake fluid drops from a lower end of a rear end portion 102a of the piston and for guiding the brake fluid dropping on the communication path P1 toward the outside thereof. <P>COPYRIGHT: (C)2011,JPO&INPIT |
