| 摘要 |
PROBLEM TO BE SOLVED: To reduce a reaction force transmitted to a brake pedal so as to provide a great braking force by moving a switching valve means forward via a valve plunger and a key member in case of quick braking, closing the first path while opening the second path, introducing the atmospheric air in a variable pressure chamber into a pressure chamber, and moving a piston forward. SOLUTION: A pressure chamber C is formed on the rear side of a piston 27, and a fixed pressure path 17 in a valve mechanism 11 is communicated to a fixed pressure chamber A via the pressure chamber and the first path 34 formed in a piston. The pressure chamber C is also connected to a variable pressure chamber B via the second path 35 formed in a valve body. The first path 34 and the second path 35 are selectively opened/closed by means of a switching valve means 36 interlocking with a key member 37. An output shaft 28 is arranged on the front side of the piston 27, while a valve plunger 13 is interlocked with the rear side via a reaction disc 26. |
