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Browse Prior Art Database

DASD Spindle Grounding System

IP.com Disclosure Number: IPCOM000115759D
Original Publication Date: 1995-Jun-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 64K

Publishing Venue

IBM

Related People

Lee, CH: AUTHOR [+2]

Abstract

A new grounding scheme for the spindle of a Direct Access Storage Device (DASD) offers the possibility of reducing the spindle resistance to ground to a few megohms permitting reliable operation of the head-disk interface. The invention described in this disclosure utilizes commercially available conductive grease to reduce the spindle resistance to ground. In the thrust bearing area, by locating the grease close to the rotational axis, power dissipation is kept to a very minimum. In the journal bearing area, some amount of power dissipation is unavoidable, although it can be reduced by proper design of the actual geometry. A low surface tension barrier film is used in the area immediately next to the grease to prevent migration of the oil to and from the grease.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 61% of the total text.

DASD Spindle Grounding System

      A new grounding scheme for the spindle of a Direct Access
Storage Device (DASD) offers the possibility of reducing the spindle
resistance to ground to a few megohms permitting reliable operation
of the head-disk interface.  The invention described in this
disclosure utilizes commercially available conductive grease to
reduce the spindle resistance to ground.  In the thrust bearing area,
by locating the grease close to the rotational axis, power
dissipation is kept to a very minimum.  In the journal bearing area,
some amount of power dissipation is unavoidable, although it can be
reduced by proper design of the actual geometry.  A low surface
tension barrier film is used in the area immediately next to the
grease to prevent migration of the oil to and from the grease.

      The disclosed invention involves the use of conductive grease
between the rotating and the stationary parts of the spindle.  A
metallic needle or a blade attached to one of the parts provides the
conductive path to reduce electrical resistance and establish
grounding.  The conductive grease is a commercially available product
where metallic or conductive carbon particles are uniformly dispersed
using proprietary methods using some surfactants to prevent
coagulation of particles.

      One of the embodiments of the subject concept incorporated into
a spindle is shown in the Figure.  The spindle design shown in this
figure utilizes hydrodynamic oil lu...