| 摘要 |
PURPOSE:To reduce the weight of a booster piston and easily fabricate various pistons by dividing the booster piston into a flanged center boss and a rounded plate abutting the rear face of the flange. CONSTITUTION:A booster piston 2 is built up from two parts of a center boss 2a of synthetic resin having a flange 3 thereon and a rounded plate 2b of steel which abuts the rear face of the flange 3. Both of a beed 4a on the internal periphery of a diaphragm 4 and the rounded plate 2b are interposed between the flange 3 and a locked ring 5 throughout the periphery of the center boss 2a. A resilient pressing member 5a for loading the rounded plate 2b and the locked ring 5 are integrated into a whole in the vicinity of a through-hole 34 in the diaphragm 4 through which a tie rod 11 passes. Bumpty engaging portions 40-45 are formed among three combinations of the rounded part 2b and the diaphragm 4, the flange 3 and the rounded part 2b, and the center boss 2a and the locked ring 5, so as to determine the circumferentially relative positions of the combinations. |
