| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a coining method to a punched surface by which the fatigue strength of a member having a punched surface is improved. <P>SOLUTION: This method is a coining method by which the punched surface 9 of a metallic sheet 1 is enlarged in the outward direction while advancing a coining punch 10B having a tapered part 11 which is narrowed toward the tip from the exit side to the entrance side of the punching after punching the metallic sheet 1 and, in this coining method after punching, the coining punch 10B in which the coefficient of dynamic friction of the surface 11a of the tapered part 11 to be brought into contact with the punched surface 9 is taken as≥0.3 and the cone angleθ1 of the tapered part 11 to the advancing direction P1 is taken as 1-30°is used. It is preferable that the coining punch 10B has a second tapered part 12 whose tapered angleθ2 to the advancing direction P1 is taken as 40-90°. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
