| 摘要 |
A first spoke connects a first point of a boss and a first joining point of a rim. A second spoke connects a second point of the boss different from the first point of the boss and a second joining point of the rim opposite to the first joining point of the rim to the boss. Each of the first and second spokes is in a plate shape. The first spoke has a circular first hole in a portion of the first spoke located at a middle in a longitudinal direction of the first spoke and at a center in a widthwise direction of the first spoke. The second spoke has a circular second hole in a portion of the second spoke located at a middle in a longitudinal direction of the second spoke and at a center in a widthwise direction of the second spoke. |
