| 摘要 |
PURPOSE:To simplify the process for production of a cutter die and to cut a stepped shaft-shaped product without affecting adversely the product in a titled method for roll-forming of said product by a two-pieces production method by forming preliminarily a semi-finished product into a specific tapered shape. CONSTITUTION:A blank material 4 is roll-formed by a forming die 2 to the shape having a part 4-3 equal to the shaft diameter of the final product, a tapered part 4-2 and a central part 4-1 having a small diameter. The sum of the lengths of the parts 4-2 and 4-3 is the length of the shaft part of the final product. The part 4-1 is then subjected to working by a cutter die 3 and the worked volume 4-4 of the excess metal expelled by the die 3 is built-up on the part 4-2 to form a part 4-5 by which the desired product shape is formed. The material 4 is finally cut by the die 3 shown in the last figure. The under-fill in the tapered part at the shaft end is then made up by the volume worked by the cutter die so that the formed product is kept free from elongation. |
