| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing apparatus of a piercing nut and a manufacturing method of the same which can excellently form a pilot part.SOLUTION: A manufacturing method of a piercing nut comprises the steps of: applying a work (first work) in which principally a flange part 9 is formed, a pilot part 6 is preformed, and a protruding part 6c is formed in a first forging mold 30; applying a work (second work) in which principally a through hole is preformed in a second forging mold; and applying a work (third work) in which principally the through hole is formed, an end face of the pilot part is flattened, and an outer peripheral surface of the pilot part along the protruding part is inclined to a penetration direction in a third forging mold. Two projecting rows 41 provided in a first punch 40 are disposed at respective positions opposite to corresponding first processing grooves 36 with first work space 35 sandwiched in the first work, and therefore a region corresponding to the protruding part 6c can be pressed from an opposite side of the pilot part 6 (that is, a body part 7 side).SELECTED DRAWING: Figure 38 |
