| 摘要 |
PURPOSE: To provide a vacuum booster reflecting the intention of an operator straightforwardly by providing mechanism for exciting a solenoid in the booster so as to acid output other than reinforcing power by input when the brake pedal operating speed of the driver exceeds the limit value. CONSTITUTION: The input side end part of a plunger member 18 fittingly mounted in a power piston 10 driven by the differential pressure of constant pressure chambers 6, 8 and transforming chambers 7, 9 is provided with an approximately annular atmosphere control seal valve 25a, and an approximately annular vacuum control seal valve 10a formed at the inner surface of the power piston 10 protrusively toward the input side. A control valve 23 with one end part having annular seal parts 23a, 23b brought into contact with and detached from the seal valves is provided, and a solenoid 17 is provided to move the plunger member 18. When the brake pedal operating speed of a driver exceeds the limit value, a current is applied to the solenoid for excitation, so as to add output other than reinforcing force by input to an output rod 15. |
