| 摘要 |
An intermediary die 10 is provided with inner circumferential helical teeth r, a lower punch 7 is provided with outer circumferential helical teeth p, and an upper punch 8 is provided with outer circumferential helical teeth q, respectively. When the intermediary die 10, the lower punch 7 and the upper punch 8 all engage to manufacture helical gears by compacting powdered materials, lateral displacement (phase displacement) of a phase guide 11 which is adapted to engage with the upper outer punch 8a, is forcibly corrected to allow it to return to its original position, from the time when the load of the upper outer punch 8a is reduced to when the intermediary die 10 is released. There is also provided an escape surface on the pressing surface of the upper outer punch 8a. The escape surface is designed to reduce the slide contact force developed on a compacted product Ga when the upper outer punch 8a and the compacted product Ga are respectively displaced in a lateral direction.
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