| 摘要 |
PURPOSE:To make the automatic retention of a braking force by interposing an electromagnetically operating valve in a hydraulic pressure path between a master cylinder and a wheel cylinder, and keeping a braking hydraulic pressure by the valve from the stop to the start of a vehicle. CONSTITUTION:The hydraulic pressure from the master cylinder when braking is applied is transmitted via a port 7, liquid chambers A, B, and a port 6 to the wheel cylinder so that the brake is actuated. When the vehicle is stopped, a solenoid 3 is magnetized, and an armature 13 is attracted to the left. Accordingly, a sheet member 8 is pushed to the left, the sheet surface 8b abuts on a ball (b), and the liquid chamber A and the liquid chamber B are cut. Therefore, the braking pressure at that time is kept in the output liquid chamber B. In this state, when the master cylinder is pressurized again, if its hydraulic pressure exceeds the hydraulic pressure in the liquid chamber B, the pressure liquid flows via a piston cup 9 from the liquid chamber A to the liquid chamber B to increase the braking pressure. When the solenoid is deenergized by the starting operation the braking is released. |
