| 摘要 |
PROBLEM TO BE SOLVED: To prevent degradation in balance even when a liquid dynamic pressure bearing is used in an inclined state or turned state, in the liquid dynamic pressure bearing provided with a magnetic balance means for holding balance of a shaft at the time of starting or stopping of rotation using repulsion of a magnet, and a spindle motor using the liquid dynamic pressure bearing. SOLUTION: This liquid dynamic pressure bearing is constituted of a shaft 1 comprising a column member 2 and a ring-shaped thrust member 3 magnetized in a rotation shaft direction, a sleeve 4, and an annular cover member 5. Permanent magnets 11 and 12 for balance magnetized in the rotation shaft direction are disposed at an upper end part and a lower end part, respectively, in a direction of magnetic poles so as to generate magnetic repulsion between the permanent magnets 11, 12 and the magnetized thrust member 3. In this manner, magnetic balance means is formed by the liquid dynamic pressure bearing itself. Further, in another embodiment, only one permanent magnet for balance is used, and the annular cover member 5 is magnetized in the rotation shaft direction and also used as the permanent magnet for balance.
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