| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method for a powder molding of an umbrella-shaped gear with a boss by which the occurrence of burrs on the tooth part of the compact is prevented by optimizing the occurrence position of the burrs in the compact. SOLUTION: Material powder is filled in a cavity which is formed of a core rod 1, a floating type main die 2, a hollow outer lower punch 5, and a hollow inner lower punch 6. Next, a sub-die 7 having a die surface corresponding to the outside-diameter surface, the tooth surface, and the top of the compact, and an upper punch 8 which is fit into the sub-die vertically movably and has a die surface corresponding to the top of the compact are made flush with one another, and the sub-die is lowered in this state and brought into contact with the main die. After that, compressive molding is performed with the upper punch, the outer lower punch, and the inner lower punch. COPYRIGHT: (C)2005,JPO&NCIPI
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