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Browse Prior Art Database

Reducing Motor Excitation to Casting/Bearings

IP.com Disclosure Number: IPCOM000113836D
Original Publication Date: 1994-Oct-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Boutaghou, ZE: AUTHOR

Abstract

Disclosed is a method to reduce motor (stator) vibrations from exciting structural modes by interposing a dampening material between the spindle shaft and the stator.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Reducing Motor Excitation to Casting/Bearings

      Disclosed is a method to reduce motor (stator) vibrations from
exciting structural modes by interposing a dampening material between
the spindle shaft and the stator.

      Spinning disk drives at high speeds excites the motor at high
frequencies; these high frequencies in turn excites the stator
windings and laminations which are transmitted to the disk/slider
interface through the bearings, spindle structure, disks, casting,
and the actuator assembly.

      The interposition of the dampening material between the stator
and the shaft reduces the amplitude of the excitations transmitted to
the bearings and to the structure.  The vibration isolation reduces
the spindle NRRO and file acoustics.  A variety of dampening
materials are commercially available.  The best candidates are
materials with visco-elastic properties with anysotropic properties.
The anysotropic properties are desirable because the radial
components of the excitation forces are much greater than the axial
components.  Thus, requiring the dampening material to provide high
damping characteristics in the radial direction.

The Figure shows the preferred embodiment of the concept for an
in-hub motor design.