| 摘要 |
PROBLEM TO BE SOLVED: To reduce the manufacturing man-hours in a process for manufacturing vehicular parts provided with a cylindrical boss by previously forming a plate- like member with a hole having a diameter smaller than the boss diameter, performing plural time of drawing so as to form a cylindrical boss, and pressing a residual part when necessary so as to form a main body part. SOLUTION: A rolled steel plate B is previously formed with a hole (h) having a diameter smaller than the boss diameter at the predetermined position thereof. After performing the drawing so as to form a large diameter shallow bottom with a punch (a), the rolled steel plate B is fed so that drawing is performed by a smaller punch (b), and thereafter, drawing is performed by a punch having a more smaller diameter and a more deep depth. This working is repeated from the working for a large diameter shallow bottom to the working for a small diameter deep bottom. After forming a boss part having a desirable shape, holes are opened over the whole area of the bottom surface of the boss part by a punch (p), and continuously, a product shape part (s) having a necessary dimension including the boss part is punched out. Thereafter, the punched product shape part (s) is bent by pressing, and broach and heating are performed when necessary so as to form a desirable part.
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