| 摘要 |
PURPOSE:To perform automatic control over a brake with a simple structure, by operating an actuator being interposed in a passage between a master cylinder and a wheel cylinder with hydraulic pressure out of a pressure source, while making hydraulic pressure in the wheel cylinder go up to some extent. CONSTITUTION:In time of stepping operation on a brake pedal 1, in the normal case that a hydraulic pump 12 is in a state of being operatable, hydraulic pressure in the pump 12 is fed to a pressure chamber 25 of a brake controlling actuator 20c by valves 30 and 32 controlled for selection by a controller 34. Accordingly, a piston 22 is moved to the left, and a hydraulic pressure inflow port 24a is closed. Action of hydraulic pressure from a master cylinder 2 to a wheel cylinder 4c is cut off, while with movement of the piston 22 to the left, hydraulic pressure to the wheel cylinder increases. In time of bra king by the stepping operation of the brake pedal 1 alone as well as in time of operation failure in the pump 12, the piston 22 is located at a right end portion, an the hydraulic pressure in the master cylinder 2 is directly transmitted to the wheel cylinder 4c. |
