| 摘要 |
PROBLEM TO BE SOLVED: To perform injection molding with good productivity by a method wherein a molding material is filled in a mold by injection when a movable mold or its part is under a condition retreated by a predetermined distance from a specified position for constituting the final shape of a molded article of a pulley and a movable side mold or its part is forwarded to a specified position. SOLUTION: A mold is closed and a molding material is filled under a condition where a local press pin 6 is retreated by a predetermined amt. from a specified position. Thereafter, the local press pin 6 is rapidly forwarded to a specified position by an outer force such as a hydraulic press to form the shape of a molded article. Then, after the molding material is sufficiently cured or solidified, the mold is opened to take out a molded resin pulley. As the local press pin 6, e.g. a structure wherein another plate 9 for local pressing is provided and stood on the back face of a protruding plate 8 is pref. It is possible thereby to prevent approximately completely strength from decreasing caused by welding while good productivity is held. |
