| 摘要 |
PURPOSE: A spindle motor is provided to increase shafting stiffness by forming a radial dynamic pressure bearing unit in a minute gap between a sleeve and a thrust plate at a right angle to a shaft, thereby reducing RRO(Repeat Run Out). CONSTITUTION: A spindle motor(100) comprises a rotation unit including a rotary shaft(110), a thrust plate(120), a hub(130) and a magnet(140); a fixed unit including a sleeve(150), a base(160), an armature(170), a cover(180) and a sealing member(190); and a fluid dynamic pressure bearing unit formed by being filled with working fluid. The spindle motor is formed with a radial dynamic pressure bearing unit(RB) which is a fluid dynamic pressure bearing unit formed by being filled with working fluid. The radial dynamic pressure bearing unit is formed with a minute gap between the rotary shaft and the sleeve at a right angle to the rotary shaft; with a first fluid dynamic pressure bearing unit(RB1) by being filled with working fluid; with a minute gap between the thrust plate and the sleeve; and with a second dynamic pressure bearing unit(RB2) by being filled with working fluid.
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