| 摘要 |
PURPOSE:To obtain a forging device that can form a inversely tapered concavity easily and easy to part a lower die by sliding a die held by the umbrella part at the tip of the rod and a die holder provided on the outer periphery of a lower die vertically along a tapered groove of the lower die and letting the die going in and out radially on the outer periphery of the lower die. CONSTITUTION:A concavity Gb is formed following the sequence of process shown by 3, 4, 5 in the figure on a material G1 cut to weight corresponding to the formed product of material G and heated to a temperature suitable for forging and a material 5b of the process 5 is obtained. Then, a lower die 2 is covered with the material 5b. An upper die 7 is lowered and the material G is fitted in the inner diameter 7a. At the same time, the opening of the material is forged to desired inversely tapered concavity by a die 4 positioned to a groove 2b in the upper part of the lower die by lowering pressure of the upper die 7 and inner diameter of the upper die. When the upper die 7 is raised, diameter of outer peripheral line connecting each die 4 in the groove part 2b is made smaller than inner diameter of the opening of the material. Under this condition, ascent of the lower die 2 is stopped and the upper die 7 is raised, and the material G is parted from the lower die 2 with the material G fitted in the upper die 7. |
