| 摘要 |
PURPOSE:To easily manufacture a rim having a variation in its thickness, by working in advance a material having a necessary thickness difference, by use of a punch and a die, and after that, finishing it to the rim, when manufacturing the rim for a wheel made of an Al alloy. CONSTITUTION:As for an Al alloy wheel for an automobile, the thickness ta of an outside rim part (a) is thicker than thickness tb of an inside rim part (b). When manufacturing a rim having such a thickness difference, an Al alloy material 30 is press-worked in advance by a press machine provided with an inside die 22, an outside die 23, and a punch 20 having a center expanded diameter part 20B of specific size, and a homogeneous cylindrical rim material 10 which is varied in its thickness and has no seam line in the circumferential direction is manufactured. It is worked to a rim 1 by a method such as well- known ring roll working, etc., and a rim having a prescribed thickness difference is manufactured easily. |
