| 摘要 |
<p>PURPOSE:To prevent generation of buckling due to an axial load of a cylindrical body, by forming the cylindrical body like a drum by vacuum suction from the outside, when forming a working part such as a flange part, etc. under the axial load, on the opened end part of a low rigidity straight cylindrical body. CONSTITUTION:For instance, when a flange part, a curl part, a double wind-clamping part, etc. for instance, a neck-in part 8 is provided on the opened end part of a piece vessel 4 having a bottom 1, of a straight cylindrical drum part 7 made of a low rigidity material, the vessel 4 is placed on a supporting board 18. Subsequently, the vessel 4 is closed up from the outside by a supporting body 10 having a lot of small through-holes 13, whose section in the axial direction of an inside surface 11 has been recessed a little toward the outside like a bow, through an outside cylinder 14 by a pressure device, and it is vacuum-absorbed through a conduit 16, a chamber 15 and the holes 13. As a result, the vessel 4 is made to tightly adhere to the surface 11, and the drum part 7 swells out like a drum. Subsequently, a necking die 19 and a core 20 are made to descend, and the neck-in part 8 is formed. Subsequently, when the chamber 15 is set to the atmospheric pressure, the drum part 7 is restored to its original shape except the working part.</p> |
