| 摘要 |
Pillars (10) connect to the inner peripheral surface (5b) of a large-diameter rim (5) and to the outer peripheral surface (7b) of a small-diameter rim (7). The inner peripheral surface (5b) of the large-diameter rim (5) and the outer peripheral surface (7b) of the small-diameter rim (7) each have an axially inner part (5c, 7c) which overlaps with the pillars (10) in the axial direction, and an axially outer part (5d, 7d) which does not overlap with the pillars (10) in the axial direction. A small-diameter ring member (2) is fitted inside of the axially outer part (5d) of the inner peripheral surface (5b) of the large-diameter rim (5), and a large-diameter ring member (4) is fitted outside of the axially outer part (7d) of the outer peripheral surface (7b) of the small-diameter rim (7). |
