| 摘要 |
PURPOSE:To rigidly couple primary and secondary molded pieces by opening a through hole at the primary molded piece, and injection-molding the secondary piece at both inner and outer peripheries of the primary piece with the hole as a resin passage. CONSTITUTION:Suitable number of through holes 4 from the inner periphery of part 1 of a boss to the outer periphery of part 3 of a rim are opened at a suitable interval along the peripheral direction in the a primary molded piece A. The piece A is cooled, sufficiently molded to be contracted, set to an injection molding metal mold, resin material injected in a metal mold is first formed with the remainder 5 of a boss on the inner periphery of the part 1 of the boss, the holes 4 are then sequentially filed, and the remainder 6 of the rim and the toothform 7 are formed on the outer periphery of the part 3 of the rim. Thus, a secondary molded piece B molded in this manner is cooled to be cured, to mold the toothform 7 and the remainder 6 of the rim is molded to be contracted in an inner circumferential direction, and the remainder 5 of the boss is molded to be contracted toward the outer circumferential direction. Thus, the piece A is held by the piece B from the inner and outer peripheral surfaces, and the interior is partly penetrated. Accordingly, both are densely coupled to be integrated rigidly. |
