| 摘要 |
PURPOSE: To reduce the operation starting input by contracting the diameter of the first seat to the level same as the diameter of the second seat, and separating the first seat and the second seat of a valve body in the axial direction. CONSTITUTION: A valve body 12 is formed by separating the first seat S1 and the second seat S2 a specific size in the axial direction, and a cylindrical tubular member 12a to connect the first seat S1 and the second seat S2 is formed following the separation of both seats. Since the diameter of the first seat S1 is set at the same level as the diameter of the second seat S2, the pressure receiving area when the differential pressure produced at the front side and the rear side of the valve body 12 is operated to the valve body 12 can be increased. Consequently, the setting load of a spring 11 to maintain the airtightness of the seat S2 can be reduced, and as a result, the input of an input shaft 21 at the operation starting time of this brake booster device can be reduced. |
