| 摘要 |
<p>This invention is characterized in that, during the manufacture of an integrally-forged light alloy wheel for an automobile, an outer rim (12), which rises from the outer circumference of a disc surface (11), is formed simultaneously with the pattern of the disc surface (11) by die forging. While the die forging is carried out, an upper die (41) is changed in turn as a mounting base is moved along guide rails provided at an upper portion of a press. In order to form a flange (3) on an inner rim of a wheel having a pattern on its disc surface (11), by a spinning method after the outer rim has been formed, a pair of mandrels for clamping the disc surface (11) therebetween are used, a part or the whole of the clamping end surface of at least one of these mandrels having a shape corresponding to the pattern on the disc surface (11). When it is difficult to extend the inner flange (3) upward along a raising portion of a mandrel, the flange (3) is rolled to a certain extent, and the end portion of this flange (3) is then expanded by a press. The resultant flange (3) is pressed against the mandrel again by a roller to form an inner rim. An unnecessary thin-walled portion (15), which is formed on the disc surface (11) by the die forging, is opened by plasma cutting.</p> |
