| 摘要 |
<p>A flange portion is provided with two abutting protrusions, a spacer is formed with two abutting projections, the respective abutting protrusions and the abutting projections are formed on the outside of a tightening point tightened by a tightening member (a spacer fixing bolt and a spacer fixing nut) in the width direction orthogonal to an imaginary line connecting the tightening points of the flange portions on both sides, and a gap G is formed between the flange portion and the spacer at the tightening point (an opening limb portion of a spacer mounting hole and an insertion hole limb portion of a head insertion hole) before being tightened by the tightening member, while the flange portion and the spacer come into abutment with each other at the tightening point after having tightened in a state in which the abutting protrusions and the abutting protrusions come into abutment with each other.</p> |
