| 摘要 |
A spindle motor according to the present invention comprises: a shaft; a sleeve which accommodates the shaft and supports the shaft to be able to relatively rotate; and a hub coupled to the upper part of the shaft or the upper part of the sleeve. A first dynamic pressure generating groove and a second dynamic pressure generating groove are formed axially on the upper and lower part, respectively, of at least one side of the inner circumferential surface of the sleeve or the outer circumferential surface of the shaft. A journal bearing unit is formed which comprises a first journal bearing formed by a dynamic pressure of a fluid of the first dynamic pressure generating groove and a second journal bearing formed by a dynamic pressure of a fluid of the second dynamic pressure generating groove. The second journal bearing is formed axially farther from the hub than the first journal bearing, and the dynamic pressure of the second journal bearing is greater than the dynamic pressure of the first journal bearing. |
