| 摘要 |
PURPOSE:To prevent a metallic plate to be brought to drawing from being subjected to galling by a part of a bead, by putting a larger curve to the end part being near a punch than the end part being far from the punch, in the end part of the bead provided on a metallic die. CONSTITUTION:On the upper face of a blank holder 4, two lines of beads 10 of recessed grooves whose cross-sectional shape is roughly semi-circuit are formed, and provided in a relation of R1<R2<R3<R4 so that a curve of a part being far from a punch 3 of a curve of the end part of each recessed groove becomes smaller than a curve of a side being hear the punch 3. On the lower face of a die 9, two projecting lines are provided on the positions opposed to the recessed grooves of the blank holder 4, respectively, and when a metallic plate 11 is placed on the blank holder 4 and the die 9 is allowed to descent, the metallic plate 11 is held between two lines of beads 10 and drawing is executed. In this case, magnitude of a frictional resistance generated in the bead 10 is averaged in positions of end parts of S1, S2, S3 and S4 of each bead, therefore, even if the metallic plate 11 is drawn to the side of the punch 3, it is scarcely subjected to galling.
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