| 摘要 |
<P>PROBLEM TO BE SOLVED: To ensure smooth operation of a master piston by pressing of a backup piston and to easily apply a servo liquid pressure to the whole surface of a back surface of the master piston in the abutment state of the backup piston. <P>SOLUTION: In the brake device for the vehicle, the servo liquid pressure from a hydraulic booster for adjusting the output liquid pressure of a liquid pressure generation source to the servo liquid pressure according to brake operation input is applied to a servo liquid pressure application chamber facing to a back surface of the master piston and the master piston can directly press from a rear side by the backup piston at reduction of output liquid pressure of the liquid pressure generation source. A front end of the backup piston 64 is abutted on the whole periphery of a peripheral edge of the back surface of the master piston 23 in the non-operation state of a brake operation member and a passage 139 for leading the liquid pressure from the hydraulic booster to a gap between the front end of the backup piston 64 and the back surface of the master piston 23 is formed between abutment parts of the front end of the backup piston 64 and the back surface of the master piston 23. <P>COPYRIGHT: (C)2007,JPO&INPIT |
