| 摘要 |
<p>PROBLEM TO BE SOLVED: To miniaturize a second bearing provided in a lower end of a pinion shaft by interposing a first bearing between a bearing holder fitted to an axial central part of a housing and a central part of the pinion shaft so as to receive all axial load to be applied to the pinion shaft with the first bearing. SOLUTION: A flange part 10c is provided in a second housing 10b of a housing 10 formed of a first and the second housing parts 10a, 10b. A bearing holder 30 is made to abut on the flange part 10c over a wide area, and a bearing 32 for supporting a central part 20b of a pinion shaft 20 is interposed between the pinion shaft 20 and the bearing holder 30. As a result, all axial force to be applied to the pinion shaft 20 is received by the housing 10 through a ball bearing 32 and the bearing holder 30. Consequently, a slide bearing 36 for supporting a small diameter part 20d supports the only radial force of the pinion shaft 20. Dimension around the slide bearing 36 is thereby miniaturized as small as possible, and the generation of interference with the fitting part can be avoided.</p> |
