| 摘要 |
PURPOSE:To prevent poor performance of molding and enhance the concentricity of a double cylinder part by structuring the couplings to couple the inner and outer cylinders so that the two ends of each coupling are thinner than the central part, and inclining these couplings in the same direction relative to the diametric direction of the inner and outer cylinders. CONSTITUTION:A resin molding 11, for example a pulley, is composed of a boss 12 as an inner cylinder, a wheel part 13 as an outer cylinder positioned concentrically with the boss 12, and a plurality of couplings 14 in a plate form which are positioned radially between them to couple them. Each coupling part 14 is so structured that the two ends are tinner 14a, 14b than the central part, and they are inclined in the same direction relative to the diametric direction of the boss 12 and wheel 13. Thereby generation of shrinkage in the connection part of each coupling 14 is eliminated likely associate with cooling of the resin when the resin molding 11 is to be formed, and also the flow of the resin is smoothened to eliminate poor performance of molding. |
