| 摘要 |
PURPOSE:To enable a use for long period and to prevent causing a galling on a blade by a spline tooth, by widening the intervals of blades of the part deeper than the halfway of the blade for spline tooth forming of the inside of a die hole rather than the intervals of the entrance side. CONSTITUTION:When a gear material is pressed into a die hole 28 it is formed almost on the central part in an axial direction of the die hole 28 and much load is put on a blade part 29b of the deeper side of a blade 29 for spline tooth forming and the blade part 29b is worn out earlier. Due to the blade part 29b of the deeper side of a blade 29 being made thicker than a blade part 29a of the entrance side, however, it can be used for a long time until worn out to the same thickness with the blade part 29a of the entrance side. Also an interval D between the blade part 29a and the blade part 29a of the entrance side of adjacent blades 29 each other is wider than the interval (d) between the blade part 29b of the deeper side and the blade part 29b. Consequently when a gear is extruded out of the die hole 28 the spline teeth of a gear are not ironed by the blade part 29a of the entrance side of the blade 29. So no galling is caused and a gear is easily extruded from the die hole 28.
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