| 摘要 |
A method and a mold die are provided for forming a spiral bevel gear from metal powders. The method includes the steps of: (a) providing a mold die having a die cavity that includes a middle segment corresponding to a contour of a spiral bevel gear, an upper segment corresponding to a contour of a first spiral gear and disposed immediately above the middle segment to form a first juncture, and a lower segment corresponding to a contour of a second spiral gear and disposed immediately beneath the middle segment to form a second juncture; (b) closing the lower segment by screwing the second spiral gear in the lower segment; (c) filling the die cavity with metal powders; (d) closing the cavity by screwing the first spiral gear into the upper segment; (e) pressing the metal powders by continuing the screwing actions of the first and second spiral gears until the second spiral gear reaches the second juncture and the first spiral gear stops short of the first juncture to form a green compact which acquires a shape of a combination of the bevel spiral gear and a residual portion; (f) screwing the first spiral gear out of the first segment; and (g) gradually screwing the second spiral gear towards the middle segment such that the residual portion is rotated along the upper segment in order to eject the green compact out of the middle and upper segments.
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