| 摘要 |
PROBLEM TO BE SOLVED: To form a side wall part without developing the defect, such as crack, fracture, in a metal blank and to form a stem guide having high projecting height downward and high precision. SOLUTION: Connecting parts 4, 5, 13, two side wall lower parts 3a of the side wall parts 3, two projecting parts 14 projected over a rocker arm width to the outside part from the side wall lower parts 3a and also, two stem guide parts 9 projected downward from a pad surface 8 of the connecting parts 5 at the tip parts of the side wall lower parts 3a, are formed by compressively working the metal wire blank with a cold-forging. Two side wall upper parts 3b of the side wall parts 3 are formed by applying an ironing to at least one part of two projecting parts 14 and thus, two side wall parts 3 held into the rocket arm width are formed. The projected height downward from the stem guide parts 9, is increased by applying the ironing to two side wall parts 3 from the outer surface side. COPYRIGHT: (C)2007,JPO&INPIT |
