| 摘要 |
PURPOSE:To perform smooth starting motion in a vehicle by installing a first on-off valve, opening or closing a passage interconnecting a valve mechanism to a constant pressure chamber, in a brake servo unit, and feeding the first on-off valve with a pressure fluid being led into a transformer vault of a clutch booster and making it perform its on-off operation. CONSTITUTION:A power piston 2 is installed in a shell 1 of a brake servo unit A free of slide motion, while a diaphragm 3 is installed on the back of this power piston 2, and the inside of the shell 1 is partitioned off into a front constant pressure chamber 4 and a rear transformer vault 5 by the power piston 2 and diaphragm 3. A first on-off valve 21, holding a brake in an operating state and retaining a vehicle in a stoppage state, is set up in the constant pressure chamber 4 and attached to a valve body 6, and thereby a vacuum passage 8 is made so as to make possible to be opened or closed by the first on-off valve 21. A conduit 22 drawn out of the first on-off valve 21 of the brake servo unit A is connected to a transformer vault 5' of a clutch booster B via a second on-off valve 32 being opened when the vehicle is tilted as far as more than the specified value due to an uphill road. |
