| 摘要 |
PURPOSE:To smoothly mold a toothed drum having high accuracy, and to elevate the productivity, by making a moving male metallic mold go down to a fixed female metallic mold which has arrayed molding parts at equal intervals on the inside wall, and reducing and molding a punched disk. CONSTITUTION:On a punched disk loading part 3 of the upper part of a fixed metallic mold 1, a punched disk 2 is loaded, fitting its center through-hole 2' to a positioning projection 17 of a moving bottom part male metallic mold 16. Subsequently, a moving male metallic mold 12 is made to go down, and the punched disk 2 is reduced and molded along the curcular arc surface of the first reducing and molding part 4 on the lower surface of the male metallic mold 12. Subsequently, the punched disk is reduced and molded to an inverted head conical shape along a reverse truncated-crest shape and inclinded strainght line surface of the decond reducing and molding part 5 connected to the lower part of a molding part 4. After that, it is pressed into a stand-by tooth form molding part 6 by the further going-down male metallic mold 4, is pressed into the third reducing and molding part 9, molding a stand-by tooth form in accordance with a gradually increasing an arc stand-by tooth form 7, and a material is pushed into a finished tooth form formed on the inside wall and a tooth form 13 formed on the outside wall of the male metalic mold 12, by which a toothed drum is molded. In this regard, as for an inside circumferential tooth form 24 and an outside circumferential tooth form 23, one is made a regular tooth form and the other is made only hollowed and projecting lines. |
