| 摘要 |
PURPOSE:To reduce the eccentric amount of a peripheral flange to a central flange by providing a preliminary flange slightly larger than the peripheral flange, reducing its diameter as far as that of the peripheral flange and providing the central flange based on the peripheral flange. CONSTITUTION:An octagonal blank 41 is blanked from a coil material to draw a discoid overall preformed article 42. Then, two stages of drawings are carried out to the overall preformed article 42 to obtain a work W. There is provided the preliminary flange 49 having an external diameter D+alpha larger by several mm than that of the peripheral flange joined to a wheel rim. The diameter of the preliminary flange 49 is reduced as far as that of the peripheral flange 50 having a required external diameter D and simultaneously the central flange 54 having a required internal diameter is provided nesting the peripheral flange 50 high in working precision.
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