| 摘要 |
PURPOSE: To dispense with a slip-out preventing means for a retainer or the like by radially bending the piston side end part of a spring for energizing a piston toward a rear shell so as to make this end part face the base end part of an output rod. CONSTITUTION: In a tandem type vacuum booster, a constant pressure chamber 3a and a variable pressure chamber 3b on the front side are partitioned by a front diaphragm 5, and a constant pressure chamber 3c and a variable pressure chamber 3d on the rear side are partitioned by a rear diaphragm 6. Control mechanism 13 is mounted in a piston 15 passing the opening part 2c of a rear shell 2 so as to be extended into a housing 3, and a spring 16 is interposed between the front end part of the piston 15 and a front shell 1. The piston 15 side end part 16a of the spring 16 is extended radially inward so as to face the base end part 9a of an output rod 9 with a specified clearance. The engagement between the end part 16a of the spring 16 and the base end part 9a of the output rod 9 thereby prevents the output rod 9 from slipping out of the piston 15. |
