| 摘要 |
<p>A means which can enhance fatigue strength of ear portions which are high fatigue risk parts in a torsion beam almost without bringing about disadvantages in terms of productivity and cost is provided. To be more specific, in manufacturing the torsion beam by forming a tubular body 1, a portion of the tubular body is formed into an approximately U-shape in cross section by crushing the portion of the tubular body in the radial direction and, thereafter, due to bending with a bottom line 3 set as a belly side of bending, a bending strain of 2 to 6% in the tube longitudinal direction on a tensile side is imparted to the ear portions 2.</p> |
