METHOD OF MANUFACTURING POLY-V-GROOVED PULLEY

摘要

A method of manufacturing a poly-V-grooved pulley having formed therein two-stage poly-V-grooves with larger and smaller diameters, comprising the steps of forming a sectionally disc-shaped first formed body (25) having a support base plate (6) and a conical circumferential wall (24) continuously extending outward in an expandingly inclined shape from the outer circumferential edge of the support base plate (6) by bending a circular plate material (23) with a boss (5) at the center thereof, forming a second formed body (34) by spreading the conical circumferential wall (24) in an expanding edge direction, forming a diameter-reduced cylinder (3), a stepped part (7) and a diameter-enlarged cylinder (11) by drawing the thickness-reduced conical circumferential wall (24) of the second formed body (34), and finally forming by rolling a poly-V-grooves (2, 10) in the outer circumferential surfaces of the diameter-reduced cylinder (3) and the diameter-enlarged cylinder (11) respectively.