电脑硬盘有较大的存储容量、要求快速、平稳、可靠地运转。硬盘主轴电动机的旋转轴一般采用球轴承支撑。由于球轴承内滚珠和滚道的金属接触,轴承会产生振动和杂音。滚珠和滚道的几何形状总有不完美之处,所产生的非反复性振动阻碍了硬盘取得更高的磁道密度。目前流体动力轴承正在迅速取代硬盘主轴电动机的球轴承,它的振动和杂音都很小。图1为典型的采用流体动力轴承的硬盘主轴电动机,电动机内有两个轴颈轴承和两个止推轴承。轴颈轴承的交叉沟道刻在旋转轴上或者静止套筒上。止推轴承的交义沟道或螺旋沟道刻在旋转止推板或者静止止推板上。沟道具有抽吸效应并能减少泄漏。计算机机壳内有芯片和电动机等热源。电动机内的流体动力轴承在开始转动时是室温。随着计算机内温度的上升,轴承要在高达80℃的温度下旋转。图2为计算机内硬盘顶部和底部的温度上升情况。温度由热电偶传感器测量。计算机内 Computer hard drive has a larger storage capacity, requiring fast, smooth, reliable operation. Rotary shaft of hard disk spindle motor generally adopts ball bearing support. Due to the ball bearings and ball raceway metal contact, the bearings will produce vibration and noise. Ball and raceway geometries are always imperfect and the resulting non-repetitive vibrations prevent the drive from achieving higher track densities. Currently hydrodynamic bearings are rapidly replacing the hard disk spindle motor ball bearings, its vibration and noise are small. Figure 1 shows a typical hard disk spindle motor with hydrodynamic bearings with two journal bearings and two thrust bearings. The cross-channel of the journal bearing is engraved on the rotating shaft or stationary sleeve. Thrust bearing groove or spiral groove on the rotary thrust plate or static thrust plate engraved. The channel has a pumping effect and reduces leakage. There are chips and motors in the computer case and other heat sources. The hydrodynamic bearings in the motor start at room temperature. As the temperature in the computer increases, the bearing must rotate at temperatures up to 80 ° C. Figure 2 shows the temperature rise in the top and bottom of the hard drive inside the computer. The temperature is measured by the thermocouple sensor. Inside the computer