| 摘要 |
PROBLEM TO BE SOLVED: To secure maintaining of braking force even when a pressure supply becomes impossible during braking by external supply pressure. SOLUTION: This brake actuator 6 is arranged among a master cylinder 3, a fluid pressure booster 2 (external fluid pressure source) and wheel cylinders 8RR, 8FL, 8FR and 8RL and regulates brake fluid pressure to the wheel cylinders 8FR, 8RL, 8RR, 8FL by using external fluid pressure from a fluid pressure booster 2. In this case, when boost pressure (external supply pressure) from the fluid pressure booster 2 becomes lower than master cylinder pressure, a hydraulic operating valve EMV interrupting communication of a booster valve CSB, a pressure reducing valve CSD and a back pressure chamber of a conversion cylinder CCYL is provided. |
