| 摘要 |
PROBLEM TO BE SOLVED: To increase the brake fluid pressure of a master cylinder in the failure of a power source, and prevent the brake fluid pressure from unnecessarily increasing when it is normal. SOLUTION: When a brake is operated in the normal state of a pump 4, the braking is performed by the power intensifying action of a hydraulic pressure assistor 3. The operating fluid pressure of the assistor 3 is accumulated in an accumulated 10, and the operating fluid pressure of the accumulator 10 is intensified by the operation of an operating fluid pressure intensifying valve 11 and supplied to the chamber 40 of a brake fluid pressure intensifying valve 8. This makes the power intensifying action of the brake pressure intensifying valve 8 impossible. When the brake is operated in the failure of the pump 4, a failure detecting valve 12 is operated to supply the operating fluid pressure of the accumulator 10 to the assistor 3, and the assistor 3 performs the power intensifying action. Since the pressure intensifying valve 11 is non-operable although no power intensifying action is performed by the assistor 3 because of the failure of the pump 4 and the reduction in operating fluid pressure of the accumulator 10, the fluid pressure intensifying valve 8 can perform the power intensifying action. |
