| 摘要 |
A roller retainer 11 encloses an outer periphery of the roller 9 situated on a diagonal 20 when the roller 9 is viewed from the side surface thereof. Whether the rollers 9 are arranged in a parallel manner or in a cross manner, the roller retainer 11 is able to keep a constant position. Furthermore, since the roller retainer 11 restricts a corner portion 9a of the roller 9, the roller 9 is difficult to slip off the roller retainer 11 and thus the roller can be positively restricted, thereby being able to control the skew of the roller 9. |
