Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Disk Hub for a Compact Disk Drive

IP.com Disclosure Number: IPCOM000112005D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Heath, J: AUTHOR [+2]

Abstract

This article discloses a method of hub construction for very compact disk drives. It allows steel to be used for the main structure of the hub rather than the more usual aluminum. This saves space as the steel hub can function as the magnetic return path for the motor rotor, so avoiding the need for a separate part.

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

Disk Hub for a Compact Disk Drive

      This article discloses a method of hub construction for very
compact disk drives.  It allows steel to be used for the main
structure of the hub rather than the more usual aluminum.  This saves
space as the steel hub can function as the magnetic return path for
the motor rotor, so avoiding the need for a separate part.

      As illustrated in the Figure, a disk drive hub (1) made of
steel has an aluminum ring attached to it that supports the disk.

The ring has a thick section (2) where it contacts the disk (5), but
a thinner section (3) connects to the point of attachment (4) of the
ring to the hub.  The attachment to the hub is rigid, such as is
obtained with a press fit.  The relative dimensions of this ring can
be adjusted so that when the temperature is varied over a wide range,
the point of contact of the ring with the disk has exactly the same
expansion or contraction as the aluminum disk.  The adjustment is
made by variation of the radial thickness of the thin section of the
ring.  The correct proportions can be found by the finite element
method of analysis.  The drawing shows a ring designed by this
method, and which prevents relative slip between hub and disk which
would otherwise have occurred.  Avoiding slip, and consequent
eccentricity of the disk, reduces the track following error of the
servo, allowing data to be recorded at a higher density.