To simply conduct a mounting worm of a joint part to a member body and to improve the yield of the member body by mounting a joint part to both end parts of a straight member body and then bending the member body to a roughly V shape or a U shape.
Bushing mounting parts 20, into which a vibration proof bushing 24 is forcedly fitted, are mounted to both end parts of a straight member body 10 made of a bar like metal hollow tube. A welded part W is preferably formed so that a protruding part 22 for connecting the bushing mounting part 20 is joined to the end face of the member body 10 by a friction agitation joining method. Next, the member body 10 is preferably pressed/bent by press-bending with using a punch and a die from the direction vertical to the axial line, the member body 10 is press-bent to a roughly U shape, a member 1 for arm is obtained. At this time, the member body 10 is preferably bent so as to have tensile strength of 10-50 kgf/mm2 and bending radiuses R1, R2 being two times or more of the outer diameter dimension D of the member body 10.
OGAWA YUICHI
HAMANO HIDEMITSU
NISHIKAWA NAOKI
TOCHIGI MASAHARU
SHOWA ALUMINUM CORP