| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method for a pulley having plural grooves which has high flexibility of designing for a mounting position with respect to a predetermined rotational shaft. SOLUTION: A pre-form 28 having a bottomed papered cylindrical shape is pinched so that the tapered cylindrical part gradually expands a diameter toward a first rim part forming part between the first rim part forming part and a second rim part forming part by using a forming die 42 which is equipped with a first die 44 and a second die 46 having the first rim part forming part and the second rim part forming part corresponding to the inner peripheral shapes of a long extended part and a short extended part in a rim part of the pulley having plural grooves. The cylindrical rim part having the long and short extended parts is formed by applying form rolling used by a forming roller 112 to the tapered cylindrical part under a condition that it is set in the forming die. Furthermore, the form rolling used by a groove forming roller is applied to this formed rim part, as a result, ring-shaped grooves are formed on the outer peripheral face of the long extended part of the rim part and the outer peripheral face of the short extended part thereof.
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