| 摘要 |
PURPOSE:To provide a device for molding a helical gear with which the simplification of the construction, the reduction of the cost, the extended life of dies, etc., are attained by fixing upper and lower punches, forming helical tooth groove to either one side of a freely rotatably supported die or core and constituting the core or die in such a manner that the core or die can move in an axial direction with respect to the lower punch. CONSTITUTION:The upper punch 3 pushes the top end face of the die 1 and moves the die and the core 2 downward with respect to the lower punch 4 as shown in the right half part of the figure when the punch 3 is moved downward after raw material powder M is packed into the die 1. The raw material powder M is, therefore, compressed between the upper and lower punches 3 and 4 and the core 6 is simultaneously rotated while said core is fitted and guided into the helical tooth grooves 4b of the punch 4. As a result, the molding M' having helical teeth 14a on the inner peripheral face, having key ways 14b on the outer peripheral face and having a through-hole 14c between the inner and outer peripheries is molded as shown in the figures (a), (b). The molding M' is thereafter taken out of the die 1 and the die 1, the core 2 and the punch 3 are reset to the raw material powder packing position shown in the left half part of the figure, by which one stage is completed.
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