| 摘要 |
PURPOSE:To prevent the generation of a crack in a side wall part, and to improve the durability of a multigroove V-pulley by bringing a plate-shaped blank to press forming roughly in a cup shape, forming a slot on the outside peripheral surface of a bottom wall of a cup body and forming it as a side wall part, and also forming a multi V-groove in the peripheral wall part. CONSTITUTION:One piece of disk-shaped blank having a uniform wall thickness is brought to press forming in a cup body 4, and thereafter, set to a fixed jig 13. Subsequently, with regard to a slot roller 9 provided with one line of projection 20, the slot roller 9 is also rotated and pressed against a peripheral wall part 8 of the cup body 7, as the cup body 7 rotates, the center part of a bottom wall part 15 and a slot side wall part 11 are formed, and also the other side wall part 10 is also formed simultaneously. Next, in the peripheral wall part 8, a multi V-groove 26 is formed by a preforming roller and a regular forming roller 26. Accordingly, after the cup body 7 has been brought to press forming, all stages are executed by a form-rolling roller, therefore, a crack, etc. are not generated in the side wall part. |
