Design and Implementation of Performance Evaluation System for Fluid Hydrodynamic Bearing in HDD

摘要

Over the past few years, hard disk drive (HDD) track densities have consistently doubled each year, but this cannot be sustained without newer technologies. A key technological bottleneck in the path to higher rotational speed, vibration damping and noise suppression, appears to be the use of ball bearings in most modern HDDs, which now seem to have reached the limit of performance. Hence, the focus today is on the potential advantages of fluid hydrodynamic bearings. At the high track densities targeted, a key performance factor for HDDs, is non-repetitive component of the runout (NRRO), which cannot be compensated for with a servo system. Here, we describe the development of a software program to extract the various components of the dynamic behavior from raw data using LabVIEW, a graphical programming environment. We theoretically review the sources of imbalance in a fluid hydrodynamic bearing, and then apply it to the design and implementation of a complete performance evaluation system incorporating our software, with specific focus on the NRRO.