| 摘要 |
PROBLEM TO BE SOLVED: To maintain rotational accuracy over a long period and to enhance reliability, by increasing a thickness in a radial direction of an outer ring in a roller bearing part, and decreasing a thickness in a radial direction of a continued bearing part between the roller bearing part and a ball bearing part smaller than a thickness in a radial direction in the ball bearing part. SOLUTION: A shaft 1 is supported by a roller/ball bearing 2, 3. The roller bearing 2 is supported by an outer ring 4 of large thickness, and the ball bearing 3 is supported by an outer ring 6 of small thickness. A part between these roller/ball bearing outer rings 4, 6 is constituted by a continued bearing part 5 of further small thickness. Accordingly, by a wide contact area of a roller as compared with a ball, supporting rigidity is higher than the ball bearing 3, and even when a ball bearing part is flawed, by thinly forming the continued bearing part 5 to a roller bearing part, displacement in a radial direction due to a flaw is absorbed by only elastic deformation of the ball bearing 3 to be prevented from being easily transmitted to the roller bearing part. |
