| 摘要 |
PURPOSE:To manufacture a pulley of an excellent accuracy and quality at good working efficiency in manufacture of a timing belt pulley by forming a rough tooth form to a normal tooth form by forging, after forming a rough tooth form provided with excess metal at an external periphery of a cylindrical drum made of a metallic sheet. CONSTITUTION:When a timing belt pulley is manufactured, first either a rough tooth form 1 provided with excess metal at an external periphery or a rough tooth form 1 provided with excess metal by increasing a diameter of the external periphery. Then, since there is a possibility that a sheet thickness of B part is decreased, in order to concentrate an elongation of the sheet to a C part forming a bottom of the tooth form, the sheet thickness of B part is secured by making a metallic punch at a K part as an angled form or reducing a radius of curvature R. Simultaneously, it is so formed as a dimension of E part is narrower and a dimension of F part larger. Then, the punch is replaced by a normal tooth form punch dies, and the E part is forged by expansing with a normal tooth form punch, and by changing the thickness of material of H, I, I a prescribed tooth form 2 is formed.
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