| 摘要 |
PROBLEM TO BE SOLVED: To prevent an influence to a bearing and a main shaft by setting a radial gap of a slide material to a radial bearing gap or less of a static pressure gas bearing forming a static pressure magnetic combined bearing and a magnetic bearing and forming a slide material by a carbon or a graphite. SOLUTION: A slide material 41 adjacent to a main shaft 4 is provided and a radial gap is made to a radial gap or less of a static pressure gas bearing surface of each radial type static magnetic combined bearing 6, 7. Thereby, in the case where an excess load is applied to the main shaft 4 and an excess load is applied to the main shaft 4 and a mechanical contact occurs between the main shaft 4 and a member at a stationary side, the mechanical contact resides in a contact of the slide material 41 and the main shaft 4. Since the slide material 41 is carbon or graphite, a friction coefficient is less. Therefore, in the spindle device 1, a damage is not caused in the main shaft 4, a bearing surface and a slide material 41. A material of the static pressure gas bearing surface is limited to a magnetic metal having no lubrication.
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