| 摘要 |
PURPOSE:To obtain a press drawn parts with the bottom excellent in flatness, by providing a groove to the inner surface of bottom along a ridgeline, in a square pillar-shaped press-drawn parts with bottom. CONSTITUTION:A press drawn parts is obtained by drawing a blank material of flat sheet having sheet thickness (t) into a square pillar-shaped body with bottom, and a groove is provided by a punch having projection, to the inner surface of bottom 4 through the whole periphery along its ridgeline. The material in the vicinity of the root of side wall 5 is moved to the outside (as a result, the radius of curvature R at the corner is made small) without causing an earing and a swell-up of bottom 4, and the flatness of bottom 4 is improved. Further, the flatness of bottom 4 is restrained to <=1/2 that obtained in a conventional method, by regulating the ratio of the depth of groove and the sheet thickness of blank material to >=0.005. |
