| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a spiral spring that can be made lightweight.SOLUTION: A spiral spring 1 comprises: an inner end 20; an outer end 22; and a spiral part 21 spirally connecting the inner end 20 and the outer end 22. The spiral part 21 comprises: an outer surface 210 including a convex part 210a extending in the longitudinal direction of the spiral part 21; and an inner surface 211 including a first concave part 211a arranged inside the convex part 210a and extending in the longitudinal direction and a second concave part 211b arranged in the first concave part 211a and extending in the longitudinal direction.</p> |
