| 摘要 |
PROBLEM TO BE SOLVED: To realize a thinner shape, an improved anti-impact resistance, a lower noise, and a lower power consumption by rotatably supporting a rotation axis with a dynamic thrust bearing, and receiving by a radial bearing a translation mode among vibration components of the rotation axis due to an unbalance force that acts upon the axis while receiving a conical mode by a thrust bearing. SOLUTION: The vibration of a translation mode is suppressed by a single radial bearing 7, while suppressing the vibration of a conical mode with a thrust bearing 9. More specifically, the diameter of the thrust bearing is set so that a moment of the thrust bearing matches with a moment due to an unbalance force of a rotating member. By satisfying the relationship expressed as L/D<1 where D denotes a diameter of the radial bearing and L denotes a width of the bearing, the vibration of the conical mode can be suppressed by means of the thrust bearing. Thus, the radial bearing 7 is only required to have a bearing stiffness sufficient only for suppressing the vibration of the translation mode of the axis 6. Therefore, even when the width of the radial bearing is set at such a size, a magnetic disk can be supported with satisfactory precision.
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