| 摘要 |
PURPOSE:To quicken output of an operation at an early stage by arranging an orifice on either passages for connecting the first pressure changing chamber or the secondary pressure changing chamber to the atmosphere without the enlargement of the whole booster. CONSTITUTION:A brake pedal is stepped on, an input shaft 21 is moved toward a valve body 7, just after the valve 26 of a control valve 24 is seated on the secondary valve seat 28, or the first valve seat 27 parts from the valve body 26 simultaneously with the progress of the input shaft 21 so that air at a atmospheric pressure flows in the secondary pressure chamber 6b via a gap between the valve body 26 and the passage 17. At this time, simultaneously the air is going to flow into also the first pressure chamber, but due to the existence of the orifice in the passage 16, air flow into the pressure chamber 5b is limited so that the air which flows in through the valve 24 concentrically flows in a pressure changing chamber 6b. As this result, pressure in the pressure changing chamber 6b rises suddenly, at a relatively early time, a rear power piston 11 is operated, a brake booster 1 outputs via an output shaft to start braking. |
