| 摘要 |
PROBLEM TO BE SOLVED: To generate a sufficient floating force in a thrust direction, further to prevent the generation of oil mist, to increase a mechanical strength, and to prevent the occurrence of the rub and seizure of a bearing. SOLUTION: A bearing hole 3A of a rotating hub 3 is filled with a fixed shaft 2, and a thrust flange 5 positioned opposite to a thrust support surface 3B is fixed at a protrusion shaft part 2C. A dynamic pressure generating groove 2B is formed in either the bearing hole 3A or the outer peripheral surface 2A of a fixed shaft 2, and a dynamic generating groove 5A is formed in either the thrust support surface 3B and the opposite surface of the thrust flange 5. By arranging a permanent magnet 7 to generate a force to push up the hub 3, the generation of oil mist is eliminated, a sufficient force is also generated in a thrust direction, and rotation precision and an increased life are provided.
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