| 摘要 |
PURPOSE:To contrive to obtain a light-weight pulley by a structure wherein recesses are provided during the forming process of the pulley on the smooth part of the inner peripheral surface of a flange part, in which V-shaped groove part of the multiple V grooved pulley without losing the durability. CONSTITUTION:The upper roll 12 and rotary internal die roll 17 of a rolling machine and a pulley 1 are rotated by rotating means respectively. When a tapered shaft 21 is moved leftward under the conditions just mentioned above, the rotary internal die roll 17, which is divided into 3 or 4 sectors, is expanded itself peripherally and at the same time the rolling edge part 13 of the upper roll 12 is pressed against the outer peripheral surface 5 of the pulley 1 of the inner and outer peripheral surfaces of the flange are rotated while being pressed strongly with the upper roll 12 and the rotary internal die roll 17. In such a manner as mentioned above, the metallic material of the flange part gradually deforms plastically, resulting in forming the recesses 6a and 6b by the intrusion of the projections 17a and 17b of the rotary internal die roll 17 into the inner peripheral surface 6 of the flange and at the same time in forming V grooves onto its outer peripheral surface. |
