We focus on the central spindle which supports the rotating magnetic platters which hold all of the data. The spindle must operate with great precision and stability at high rotational speeds. Design practice has converged on oil-lubricated hydrodynamic journal bearings as the most common choice for spindles. That is, a layer of viscous oil separates a rotating shaft (the bearing) from the fixed outer sleeve (the journal). In hard drives, it is very important for the shaft to be centered within the sleeve. Plain journal bearings (i.e. both surfaces are circular cylinders) are unstable to perturbations that push the shaft off-center. It was found that this stability problem can be overcome by cutting diagonal grooves into the journal in a pattern called a herring-bone. Another consequence of this design is that very high pressures are generated by the grooves as they drive the oil to the middle of the bearing, away from the top/bottom ends of the spindle. This pumping action generally works to oppose leakage out of the bearing.ududWe examine how choices for the groove pattern can influence the key properties of the bearing. The focus is to understand the effect of the groove geometry on the pumping action. In particular the undesirable behavior caused by the low pressures created near the top/bottom ends of the bearing which, under many conditions, may result in the pressure becoming negative, relative to atmospheric pressure. Negative pressure can result in cavitation or, when it occurs near an air-oil interface, can cause air to be ingested and hence create bubbles. Any bubbles in the oil can corrupt the lubricating layer in the bearing and, as they are created and collapse, can cause significant undesirable vibrations. The negative pressures have therefore been identified as one of the key problems in design of hard disk drive bearings.ududWe will use numerical computations and some analysis to show that by modifying the groove geometry we can reduce the negative pressure while retaining good stability characteristics.
展开▼
机译：我们专注于中心主轴，该主轴支持可保存所有数据的旋转磁盘。主轴在高转速下必须具有很高的精度和稳定性。设计实践已将油润滑流体动力轴颈轴承作为主轴的最常见选择。也就是说，一层粘性油将旋转轴（轴承）与固定外套管（轴颈）分开。在硬盘驱动器中，使轴在套筒内居中非常重要。滑动轴颈轴承（即两个表面均为圆柱体）对于使轴偏离中心的扰动都是不稳定的。已经发现，可以通过以称为人字形的方式在轴颈上切割斜槽来克服这种稳定性问题。这种设计的另一个结果是，当凹槽将油驱动到轴承的中部（远离主轴的上/下端）时，它们会产生很高的压力。通常，这种泵送作用可以阻止轴承泄漏。 ud ud我们研究了沟槽图案的选择如何影响轴承的关键性能。重点是了解凹槽几何形状对泵送作用的影响。尤其是在轴承的上端/下端附近产生的低压所导致的不良行为，在许多情况下，可能导致压力相对于大气压变为负压。负压会导致气蚀，或者当它发生在气油界面附近时，会导致空气被吸入并因此产生气泡。油中的任何气泡都会破坏轴承中的润滑层，并且在气泡形成并崩溃时会引起明显的不良振动。因此，负压已被确定为硬盘驱动器轴承设计中的关键问题之一。 ud ud我们将使用数值计算和一些分析来表明，通过修改凹槽的几何形状，我们可以降低负压，同时保持良好的稳定性。特征。
展开▼
