Browse Prior Art Database

Radial Disk Clamp

IP.com Disclosure Number: IPCOM000116518D
Original Publication Date: 1995-Sep-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Gillis, D: AUTHOR [+2]

Abstract

Disclosed is a clamp design to assemble disks to the spindle motor in hard disk drives. A cylinder with its outer radius larger than the inner radius of a disk is chosen. A set of circumferential grooves is machined on the outer surface of the cylinder. The depth of the grooves is such that the radial distance from the center line of the cylinder to the valley of the groove (outer radius - groove depth) is slightly larger than the inner radius of the disk. The width of the grooves should be slightly smaller than the thickness of the disk (to locate the disk on the hub). The cylinder is then cooled so that its outer radius shrinks to a size slightly smaller than the inner radius of the disk. The disks are then slipped over the cylinder and aligned along the grooves.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Radial Disk Clamp

      Disclosed is a clamp design to assemble disks to the spindle
motor in hard disk drives.  A cylinder with its outer radius larger
than the inner radius of a disk is chosen.  A set of circumferential
grooves is machined on the outer surface of the cylinder.  The depth
of the grooves is such that the radial distance from the center line
of the cylinder to the valley of the groove (outer radius - groove
depth) is slightly larger than the inner radius of the disk.  The
width of the grooves should be slightly smaller than the thickness of
the disk (to locate the disk on the hub).  The cylinder is then
cooled so that its outer radius shrinks to a size slightly smaller
than the inner radius of the disk.  The disks are then slipped over
the cylinder and aligned along the grooves.  As the temperature of
the cylinder increases, the disks will be radially stressed by the
expanding cylinder, and thus clamping the disk in place.

This design does not use clamp rings to hold the disks in place.
Therefore, this design:
  1.  allows more of the disk surface area to be used for storing and
       retrieving data
  2.  reduced part count for device (no spacer rings).

      Let A be the coefficient of thermal expansion for a particular
material, such as, aluminum.  Let the original outer diameter of a
cylinder be D.  The cylinder must be machined as to produce
circumferential grooves around the cylinder.  The longitudinal
distance between the grooves will depe...