| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a BBW type brake system including two hydraulic pressure lines capable of detecting that a third front cup seal of a front piston is mistakenly not installed. <P>SOLUTION: When a first hydraulic line continuous with a rear liquid chamber 39A fails and is made to open atmosphere at the time of failure of a motor cylinder 23, a forward-facing third front cup seal C5 prevents a brake hydraulic pressure generated by a master cylinder from leaking out from a front supply port 49B through the rear liquid chamber 39A, and a stopper 51 prevents a front piston 38B from moving rearward due to a pressure of a front liquid chamber 39B, thus braking by a second hydraulic pressure line continuous with the front liquid chamber 39B of the motor cylinder 23 can be ensured. When the third front cup seal C5 is mistakenly not installed, brake fluid generated by the master cylinder when a brake pedal is depressed leaks out of an atmospheric chamber 52 arranged between a second front cup seal C4 and the third front cup seal C5, increasing the brake pedal stroke, thus detecting that the cup seal is mistakenly not installed. <P>COPYRIGHT: (C)2009,JPO&INPIT |
