Method of making a clutch rotor for an electromagnetic clutch

摘要

A method of making a clutch rotor for use in an electromagnetic clutch according to this invention includes the steps of forming a cup-shaped blank with a generally cylindrical annular flange wall; applying an outward transaxial force to the annular flange wall of the cup-shaped blank to form an annular outward bulge in the flange wall forming at least one inwardly projecting approximately V-shaped groove in the annular bulge by a press operation; applying a roller working operation to the approximately V-shaped groove to form the final V-shaped groove; and pressing a portion of the bottom plate to form an inner cylindrical member.