| 摘要 |
PURPOSE:To easily position each member by making a short cylindrical member encircle a through-hole which is made in a disk of a booster piston for inserting a tie rod therethrough and by engaging the short cylindrical member with a positioning notch is formed at a flange of the center boss of the piston. CONSTITUTION:A booster piston 2 is composed of a center boss 2a made of synthetic resin and a disk 2b, shaped out of a steel plate, which abuts the rear face of a flange 3 integrally projected from the periphery thereof. A through- hole 32 in the disk 2b for inserting a tie rod 11 therethrough is encircled by a staged short cylindrical member 49 which is integrally projected on the front face of the disk 2b, so as to reinforce the disk 2b at the vicinity of the through- hole 32 therein with the short cylindrical member 49. A protective ring 43 made of synthetic resin is fit into the small diameter part 49a of the sort cylindrical member 49 to protect a portion 33b that is the rear end of a stretchable boot 33. The short cylindrical member 49 on the disk 2b and the protective ring 43 are engaged with an arc-shaped positioning notch 42 which is formed on the periphery of the flange 3 of the center boss 2a. |
