| 摘要 |
PURPOSE: A fluid dynamic bearing spindle motor is provided to reduce the size of the motor by forming journal bearing portions in upper and lower portions of the motor, respectively, while effectively preventing leakage of oil from a fluid dynamic bearing portion. CONSTITUTION: A fluid dynamic bearing spindle motor comprises a housing(110) having a core(130) arranged along the inner circumference of the housing; a sleeve(120) coupled to the center of the housing; a thrust cover(180) coupled to the bottom of the sleeve; a shaft(140) coupled to the sleeve in such a manner that the shaft is rotatable by a fluid dynamic pressure; and a hub(150) coupled to the shaft, and which has a magnet(160) arranged on the inner surface of the hub. The sleeve has a circular inner protrusion(125) formed at the inner center thereof, and a first groove and a second groove formed at the upper and lower portions of the circular inner protrusion, respectively. The shaft has a circular outer protrusion(145) coupled into the first groove of the sleeve in such a manner that the circular outer protrusion is rotatable. The fluid dynamic bearing spindle motor further includes a circular thrust plate(170) coupled into the second groove of the sleeve in such a manner that the circular thrust plate is rotatable. The circular thrust plate is fixed at the bottom of the shaft.
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