MANUFACTURE OF POLY V-PULLEY MADE OF SHEET METAL

PURPOSE:To obtain a light poly V-pulley high in accuracy using a simple device by forming a V-groove by rotary forming on the outer face of peripheral wall of a cylindrical formed product obtained by working a metallic sheet. CONSTITUTION:This manufacturing method consists of a process that forms a preliminary formed product 66 from a cylindrical formed product 64, a process that forms a flange part 90 thrusting a flange forming roller 30 from outside while rotating the formed product 66 and a process that cuts a V-groove on the peripheral wall of intermediate product 92 on which the flange part is formed. In the preliminary forming process, a U-shaped bending roller 26 is thrusted against outer face of the peripheral wall of the formed product 64 and the part corresponding to the base of the flange is bent inward. In the process of V-groove cutting, a groove forming roller 34 is thrusted from outside against peripheral wall between flange parts 88, 90 of the intermediate product 92 and a V-groove is cut between the roller and an internal roller 38.