| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a master cylinder capable of minimizing a shortage of brake fluid pressure to an input to a brake pedal in the beginning of braking even if a vacuum failure of a vacuum booster occurs. SOLUTION: A release means 123 detecting the vacuum of a engine intake system led to the vacuum booster 10 and releasing the liquid pressure of a large-diameter pressurized chamber 56 to a reservoir 12 side according to the vacuum of the intake system is provided. When the vacuum failure of the vacuum booster 10 occurs, the release means 123 detects the failure from the vacuum of the intake system and the release liquid pressure of the large-diameter pressurized chamber 56 to the reservoir 12 side. Accordingly, since the pressure of the large-diameter pressurized chamber 56 gets atmosphere pressure same as the reservoir 12 even at the beginning of the braking, a driver doesn't need to raise the pressure of the large-diameter pressurized chamber 56 with an operation of a brake pedal 2.</p> |
