| 摘要 |
PROBLEM TO BE SOLVED: To reduce noise generated by a valve mechanism 16. SOLUTION: A tandem brake booster 1 is provided with a solenoid 17 in a valve body 6. When the solenoid valve 17 is energized, a cylindrical member 21 connected with the solenoid 17 is pushed forward to open an air valve 32 and to close a vacuum valve 27. The tandem brake booster 1, thereby can be operated without applying a brake pedal. When energizing the solenoid valve 17 is stopped, a piston 57 and the cylindrical member 21 return to indicated non-operation positions. Accordingly, an end surface of a flange part 21F of the cylindrical member 21 and an end surface in a valve plunger 24 side opposing the same, which were separated before, get in contact. The cylindrical member 21 is made of synthetic resin and has many dimple parts formed on the end surface of the flange part 21F. Contact noise generated when the end surface of the flange part 21F and the end surface of the valve plunger 24 get in contact, thereby is controlled. |
