| 摘要 |
PROBLEM TO BE SOLVED: To provide a brake device which can make compatible the securement of maximum wheel cylinder pressure at a normal time and the securement of necessary wheel cylinder pressure at a failure.SOLUTION: A primary piston 323 of a master cylinder 3 is configured as a different diameter structure composed of a primary piston large diameter side 302 and a primary piston small diameter side 303, and a secondary piston 304 is configured as a small diameter structure. A reservoir communication valve 315 which, at a system normal time, cuts off a primary piston large diameter side liquid chamber 305 and a reservoir tank 4 from each other and at a failure, makes them communicate with each other, and a seal 312 which allows a flow of a brake liquid directed from the primary piston large diameter side liquid chamber 305 to a primary piston small diameter side liquid chamber 306 and separates both the liquid chambers from each other to a direction in which a flow in the reverse direction is suppressed are provided. |
