| 摘要 |
PURPOSE:To prevent generation of striking sound by operating a car stop holding means for a certain period of time when the position sensed is shortly before returning of a braking force booster from the operating condition to off-operating condition, and lowering the backward motion speed of the input shaft. CONSTITUTION:When a car is stopped for a certain period of time by stamping of a brake pedal 40, a controller actuates a solenoid valve 16 to choke a passage 15 if the car stop holding condition holds, i.e. the brake pedal 40 is being stamped over a certain while continuously. This hinders the air introduced into a pressure varying chamber 5 from overflowing into a low pressure chamber 4, and continuously braked condition is obtained even after releasing the stamping force from the brake pedal 40. In such a device, the solenoid valve 16 is re-closed for a specified period if a photo-interrupter 44 has sensed a sensing hole 40a in the position just before collision of the brake pedal 40 with a pedal stopper 43, so as to drop the backward motion speed of the input shaft 25. |
