Cold heading method for caulking nuts and caulking nuts

摘要

To provide a caulking nut of a shape that can be processed by cold heading, and provide a cold heading method.SOLUTION: A caulking nut 1 is formed with a caulking and fixing part 3 at one axial end side of a nut body part 2. The caulking and fixing part 3 includes: a press-in fixing portion 4 having the same diameter as that of the nut body part 2; and a pilot portion 5 having a diameter smaller than that of the press-in fixing portion 4. Plural recesses 7 are formed at the press-in fixing portion 4 along a peripheral direction. The pilot portion 5 is formed into an inverse tapered shape in which an outer diameter size is gradually decreased as an outer peripheral surface 11 goes from an axial-direction tip surface side toward the press-in fixing portion, a bottomed screw prepared hole 14 is opened at the axial-direction tip surface 13. A cold heading method of the caulking nut 1 includes: a first cold heading step for making an axial-direction tip side of a processed raw material to a circular truncated cone shape; a second cold heading step for forming the nut body part, the press-in fixing part, a small diameter shaft part on the processed raw material; a third cold heading step for forming the screw prepared hole; and a fourth cold heading step for making the small-diameter shaft part into the pilot portion.SELECTED DRAWING: Figure 1