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Dual Annular Seal Spindle Design for Head-Disk Assemblies

IP.com Disclosure Number: IPCOM000100599D
Original Publication Date: 1990-May-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 91K

Publishing Venue

IBM

Related People

Gilmore, J: AUTHOR [+3]

Abstract

Disclosed is a spindle design for sealed head-disk assemblies (HDAs) which isolates the head-disk surface from spindle contamination.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 53% of the total text.

Dual Annular Seal Spindle Design for Head-Disk Assemblies

       Disclosed is a spindle design for sealed head-disk
assemblies (HDAs) which isolates the head-disk surface from spindle
contamination.

      Contamination of the head-disk surface is a dominant factor in
HDA life.  There are three primary sources of debris in a sealed HDA:
 1) debris produced when accessing, 2) initial part and assembly
debris and 3) spindle bearing contamination.  The first two sources
must be sufficiently isolated from the head-disk-interface (HDI)
through design of the airflow and filtering system.  Most HDA
spindles are supported by two ball bearings inserted into the HDA
casting in the regions 25, 30 (see the figure).  The spindle
contamination source is a result of ball bearing technology which
produces particulate wear debris and outgasses low molecular weight
oils from the bearing grease.

      The spindle design must isolate the HDI from bearing
contamination for reliability of state-of-the-art HDAs. There are
three mechanisms of transport that allow contamination to migrate
from the spindle bearings to the head-disk interface:  1)
steady-state flow induced by the rotating surface of the disk hub, 2)
transient flow caused by starting and stopping the HDA (volume
expansion/contraction) and 3) diffusion.

      A dual annular seal design (see the figure) minimizes
steady-state flow by minimizing the axial clearance between the
rotating hub and the top surface of...