| 摘要 |
PURPOSE: A fluid dynamic bearing motor is provided to increase the assembly area between a hub and a shaft by increasing the diameter of the top of the shaft, while achieving improved driving characteristics of motor. CONSTITUTION: A fluid dynamic bearing motor comprises a housing(110); a hollow sleeve(120) coupled to the center of the housing; a core(130) arranged along the circumference of the housing and the sleeve; a thrust cover coupled to the bottom of the sleeve; a shaft(140) coupled to the sleeve; and a hub(150) coupled to the shaft, and which has a magnet(160) arranged at the inner surface of the hub. The shaft has a large diameter portion coupled to the hub, and a small diameter portion smaller than the large diameter portion. The sleeve includes an inner surface for forming a first journal bearing; first and second grooves formed in vicinity of the top of the inner surface of the sleeve; and a third groove formed in the vicinity of the bottom of the inner surface of the sleeve. The fluid dynamic bearing motor further includes a thrust plate(170) coupled to the small diameter portion of the shaft and to the first groove of the sleeve, and which forms a first thrust bearing; and a dynamic cover(190) coupled to the second groove of the sleeve, and which forms a second journal bearing and a second thrust bearing.
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