| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce manufacturing cost of a piston ring that is formed by bending a metal rectangular wire into a shape of C as seen from a top plan view.SOLUTION: A specified one outer surface of four outer surfaces is formed with ground traces extending along a direction different from a ground trace at the other outer surface. A sectional shape of a metal rectangular wire is formed into a rectangular form that is defined by a pair of long sides and a pair of short sides, when outer surfaces including each of the pair of long sides form an upper surface and a lower surface and outer surfaces including each of the pair of short sides form an upper surface and a lower surface, the ground traces extending along the first direction can be formed at one of the upper surface and the lower surface, and the ground traces extending along the second direction different from the first direction can be formed at the other of the upper surface and the lower surface.</p> |
