| 摘要 |
PROBLEM TO BE SOLVED: To solve such a problem that in the welding of a bracket to a side frame at a connection part (rounded bent part) of a frame comprising a pipe member of a seat-back frame, a shape of an ellipse transformed from a circle is not constant and the distance between two welding points is not stabilized.SOLUTION: A pipe member transformed from a circle to an ellipse is subjected to crushing processing in a rounded bent part, and a pair of opposing flat surfaces 24s are molded in the oblong diameter direction. An inner bracket 25i is formed substantially in a U-shaped cross section in which two edges 25ib are extended from a bottom plate 25ia so as to sandwich the oblong. The inner bracket is lapped on a rounded bent part 24-2 of the pipe member so that the edge covers oblong flat surfaces 24s across the oblong, and is welded to the rounded bent part using the flat surface 24s as a welding point S. |
