| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent increase of a hydraulic pressure of a booster hydraulic chamber at advancing of a backup piston with a simple structure having a reduced number of parts in a vehicular brake device capable of directly pushing a master piston with the backup piston from the rear part at lowering of the hydraulic pressure of the booster hydraulic chamber. <P>SOLUTION: The backup piston 88 is provided with a piston main part 88a slidably fitted with a casing 15, and a pushing part 88b slidably fitted to the casing 15 with a seal diameter smaller than the seal diameter of the master piston 26 and the piston main part 88a and continued to a front end of the piston main part 88a in such a manner of capable of pushing the master piston 26 from the rear side. An annular input chamber 96 communicating with a hydraulic pressure generation source is formed between the backup piston 88 and the casing 15, and the volume increase quantity of the booster hydraulic chamber 25 when the pushing part 88b pushes the master piston 26 to the advancing direction is almost equal to the volume reduction quantity of the input chamber 96. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
