Browse Prior Art Database

Advanced Magnet Assembly for a Rotary VCM Actuator

IP.com Disclosure Number: IPCOM000102836D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 46K

Publishing Venue

IBM

Related People

Reidenbach, JR: AUTHOR

Abstract

The illustrated assembly is designed to provide a uniform field of flux for a voice coil motor used to access a plurality of magnetic read/write heads across the surfaces of recording disks. The assembly is symmetrical side to side and top to bottom such that one half when inverted serves as the second half also. When viewed from above, the structure appears as a bowed E-shape.

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Advanced Magnet Assembly for a Rotary VCM Actuator

      The illustrated assembly is designed to provide a uniform field
of flux for a voice coil motor used to access a plurality of magnetic
read/write heads across the surfaces of recording disks.  The
assembly is symmetrical side to side and top to bottom such that one
half when inverted serves as the second half also.  When viewed from
above, the structure appears as a bowed E-shape.

      Each half of the magnet assembly consists of a steel housing 1
which serves as a high permeance return path for the magnetic flux,
outer and inner permanent magnets 2 which serve to provide the
desired flux and a curved rectangular copper tube 3 which serves as a
shorted turn to reduce the current rise time of the voice coil motor
coil.  The housing is fitted with bosses to facilitate attachment of
the magnet assembly between the top and bottom plates (not shown)
which themselves provide positioning and structural support to other
head-disk assembly elements.

      The top and bottom legs of the E-shaped cores have tapered edge
surfaces 5 and mounting locations such that when two housings are
paired together at assembly, a small gap remains between the two
halves.  The tapered edges 5 and the gap between the housings serve
to provide a high reluctance at the mid-point of the magnetic
circuit.  This feature coupled with the symmetrical return paths
assures asymmetrical distribution of magnetic flux between the two
side...