| 摘要 |
PROBLEM TO BE SOLVED: To provide a pierce nut fastening method which performs hole formation and fastening by swaging in one step, and can obtain high fastening strength.SOLUTION: A pierce nut fastening method includes: a preforming step of forming a rising part T having a height h at a predetermined part of a workpiece W1 according to the shape of a piece nut 1; and a fastening step of mounting the workpiece W1 on a die 9 having a hole part 91 engageable with the outer periphery of an inner cylinder part 12 and an annular projecting part 92 formed on the peripheral edge of the hole part 91 and insertable into an annular recess part 14 so that the rising part T is located in the vicinity of the peripheral edge of the annular projecting part 92, and, in this state, punching the workpiece W1 by the piece nut 1 until the inner cylinder part 12 is engaged with the hole part 91 to fasten the piece nut 1 to the workpiece W1. In the preforming step, the rising part T is formed so that the height h of the rising part T is larger than a value obtained by subtracting a distance d from a tip 120 of the inner cylinder part 12 to a tip 130 of an outer cylinder part 13 in an extension direction from a thickness t of the workpiece W1. |
