| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball bearing having impact resistance and not so expensive, hardly causing the temperature rise of a rotating shaft even when used as a touch-down bearing for mechanically supporting the rotating shaft of a turbo molecular pump. SOLUTION: The ball bearing adopts an inner ring 31 formed of a ferromagnetic material and an outer ring 30 formed of a ferromagnetic material. A distance between a shoulder portion 36 of a raceway groove 39 of the inner ring 31 on one axial side of the inner ring 31 and a shoulder portion 35 of a raceway groove 38 of the outer ring 30 on one axial side of the outer ring 30 is set to be 1/4 or less of the diameter of a ball 32. COPYRIGHT: (C)2008,JPO&INPIT
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