| 摘要 |
PURPOSE:To facilitate the working, by faying both ends of a hoop by welding after materials where the section has an apprximately T shape are molded to a shape like a hoop and working this hoop plastically in case that a rim having a ring-shaped faying part on the inside circumferece is produced. CONSTITUTION:Linear rim blanks 11 where the section has an approximately T shape are constituted by the extrusion of, for example, of light alloy materials and are cut to a required length corresponding to a finish rim diameter. If blanks 11 are constituted specially continuously by the extrusion, the mass production is possible, and the yield of materials is improved considerably, and homogeneousness is realized. After cut blanks 12 are molded to a shape like a hoop so that a projecting stripe 13 is inside, faces to be matched to each other of blanks 12 are welded. In this case, since a diameter (h) of blanks 12 in the direction of thickness is small comparatively and the welding region is only the flat surface part, the working is very easy. The part of blanks 12 orthogonal to the projecting stripe 13 is molded by rolls 14 and 15, which have required inside and outside shapes and face to each other, while rotating blanks 12, thus working plastically blanks 12 to a prescribed shape. |
