| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an arm which can suppress a defect during forming, and at the same time can facilitate welding to a welded portion, while securing the strength to a load in a specified direction. <P>SOLUTION: A body portion 21 of quadrangular cross section having a corner, and welding portions 22 23 of circular cross section not having the corner are press-formed simultaneously so as to form a slit 26 crossing changing portions 24, 25 in an axial direction. The excess load during forming of the body portion 21 and the welding portions 22, 23 whose welding conditions are mutually different is absorbed by the slit 26 of the changing portions 24, 25, so that the fault caused during forming can be suppressed. While securing the strength to the load in the specified direction by the body portion 21 of quadrangular cross section having the corner, by the welding portions 22, 23 not having the corner, welding can be easily performed to pivotally supported portions 14, 15. <P>COPYRIGHT: (C)2013,JPO&INPIT |
