| 摘要 |
PURPOSE:To enable an auxiliary brake for work without need for the operation of a brake pedal by dividing the front and rear negative pressure chambers of a negative pressure power device into separate negative pressure supply systems and making it possible for a chamber on one side to introduce atmospheric pressure according to the signal of an auxiliary-brake-for-work switch. CONSTITUTION:The interior of a housing 1 is divided by a partition wall 4 into the front and rear chambers F, R and respective chambers F, R are also divided by power pistons 2a, 2b and diaphragms 3a, 3b respectively into negative pressure chambers A, B and voltage transformation chambers D, C. Both voltage transformation chambers D, C are made to communicate with each other by means of a passageway 7 provided at a core portion 5. At the core portion 5, also, is formed an atmospheric passageway 7, which is opened/closed with an operating rod 8. A negative pressure source is connected with negative pressure chambers A, B through a pipe arrangement 14, and for the pipe arrangement of the negative pressure chamber on the B side, is provided a solenoid valve 15 which is openable on the atmospheric side according to the operating condition of an auxiliary-brake-for-work switch of a parking brake or the like. |
