Characteristic analysis of hydrodynamic bearings for HDDs

In this paper we describe the application of Hydrodynamic Bearings (HDBs) to conventional products and discuss the technical distinctions of HDBs between HDD applications and another applications. We also report on numerical analytical and experiments aimed at solving the characteristic problems of high-speed HDDs.

I. Introduction

Examples of conventional applications of hydrodynamic bearings in OA/AV equipment are shown in Table I. Key requirements for HDBs for a HDDs are: 1)

High spindle accuracy at the 20 nm following level NRRO (Non-Repeatable Run Out).

2)

Particle emission, outgassing of oil, and outflow of oil must be prevented for extended periods.

3)

The spindle must be able to rotate at speeds as high as 20000 RPM.