Fastening pin for hard driven member and method for forming the same

摘要

A fastening pin (A) is provided with an enlarged head part (1), and a shaft part (2). The shaft part (2) includes a large diameter section (2a) formed below the enlarged head part (1), a middle shaft section (2b) formed below the large diameter section (2a), and a small diameter section (2c) extending from the middle shaft section (2b) to a leading end of the fastening pin (A). The large diameter section (2a) includes a round portion (4) formed below the enlarged head part (1) and a taper portion (5) formed between the round portion (4) and the middle shaft section (2b). A diameter of the large diameter section (2a) at a side of the enlarged head part (2a) is larger than a diameter of the large diameter section (2a) at a side of the middle shaft section (2b). The middle shaft section (2b) has a uniform diameter from a side of the large diameter section (2a) to a side of the small diameter section (2c). A side of a leading end of the small diameter section (2c) has a bullet shape.