| 摘要 |
A press forming apparatus comprises an upper die 50 provided with a pierced hole periphery die 52, an upper drawing die 54, a punch 53, an upper movable blank holder 15 55, and a trimming member 66 and a lower die 60 provided with a lower drawing die 64, a coining punch 62, an outer periphery die or trimming member 66, and a lower movable blank holder 65. The upper die is lowered with respect to the lower die, and the outer periphery portion of a blank B 20 is held by the trimming member and the lower blank holder. Then, the blank B is trimmed by the upper drawing die. Next, the blank B is drawn by the lower drawing die and upper drawing die at the same time as the pierced hole periphery die pierces the blank and draws the inner periphery portion of the blank. Next, the blank is pierced by the punch at the same time as the outer periphery die of the upper drawing die pushes down on the lower movable blank holder to continue drawing of the central position. The coining punch presses into the pierced hole periphery die to perform the coining process as a final step, thereby obtaining a pump impeller of a turbine converter or a shell of a turbine runner. |
