| 摘要 |
PURPOSE:To manufacture a stepped hollow product having an excellent quality, with high efficiency, by utilizing a multi-stepped former, forming a hollow recessed hole whose inside diameter is different from both end faces, on a short cylindrical base material, and afte that, restricting a small diameter hollow part under the guide of a guide rod. CONSTITUTION:A short cylindrical base material 1 which has been cut to specified size from a continuous metallic rod wire material is corrected as to its end face, and after that, a recessed hole 2 is formed by making a punch rush in, and simultaneously, a shallow guide recessed part 4 which has broken a hard film 3 by a projecting shaft from the side of a die is formed on the other end. Subsequently, this recessed hole 2 is shaped as to its bottom part, and on the other hand, the guide recessed part 4 is push- expanded by a receiving base punch of the bottom part of the die, and on both end parts of the base material, desired hollow recessed holes 5, 6 having different diameters are formed. Subsequently, an intermediate part 7 of both hollow recessed holes 5, 6 is punched and penetrated, a guide rod projecting from the punch side is inserted into through-holes 5', 6', the outside circumference of the small diameter hollow hole 6' is restricting under its guidance, and a long projected small diameter hollow part 10 is formed in one body by providing a step 9 on the tip of a large diameter hollow part 8. |
