Browse Prior Art Database

Disk Drive

IP.com Disclosure Number: IPCOM000115879D
Original Publication Date: 1995-Jul-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 4 page(s) / 130K

Publishing Venue

IBM

Related People

Good, DL: AUTHOR [+5]

Abstract

With the demonstration of 150 - 200 Mb/in2 areal density using metal in gap heads, a 80 to 160 MB drive is configured. The 80 MB design point uses only one head and one recording surface of the disk. Several mechanical and electrical innovations are used. The file configured in this document can be incorporated in form factors from 3.5" and smaller. Fig. 1 displays the low cost drive concept.

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Disk Drive

      With the demonstration of 150 - 200 Mb/in2 areal density using
metal in gap heads, a 80 to 160 MB drive is configured.  The 80 MB
design point uses only one head and one recording surface of the
disk.  Several mechanical and electrical innovations are used.  The
file configured in this document can be incorporated in form factors
from 3.5" and smaller.  Fig. 1 displays the low cost drive concept.

MECHANICAL DESIGN - The base casting (Fig. 1, 1) is a flat plate
design that allows for assembly from the top.  The sides of the
casting are turned down for stiffness, mounting to the using system,
card attachment and card protection.  All surfaces are as cast except
for the actuator and spindle bearing mounting holes.

      The actuator is a single plastic arm (2) with the HSA attached
via a hot stake process.  The head leads are routed down the arm
through a snare tube (4).

      The voice coil for the actuator is a moving magnet
configuration that has a magnet bonded to the rotating actuator.  The
magnet is magnetized in two zones of opposite polarity (5).  The
stationary coil (6) is bonded to the lower pole (7) which is made of
sintered iron.  The upper pole is screwed to the lower pole on two
standoffs.  Around the standoffs are o-rings that serve as inner and
outer crash stops.  This moving magnet VCM is used to enable routing
of the coil leads directly to a pass through connector (8) that leads
to the electronics card (9).  In addition, the moving magnet actuator
provides a magnetic detent that serves as an actuator latch,
therefore, no additional parts are required for latching.

      Since the VCM coil is stationary and the leads can be directly
routed to the pass through connector, and a minimum number of head
leads are required.  The dynamic flex on the actuator is eliminated.
The head leads are routed to the pass through connector by extending
the snare tube to provide the flexible connection between the moving
actuator and the base casting.  One end of the snare tube is fixed to
the actuator while the other end is attached to a boss feature in the
base casting (Fig. 2).  The moving arc portion of the snare tube
between the boss and actuator is designed with clearance to the base
casting.  The bias effect on the actuator is minimized by making the
arc large.  The benefit of this design is the elimination of the flex
cable, and increasing file reliability by eliminating electrical
connections.

      The actuator and spindle bearings are housed in a common
bearing cartridge (10, 17) with the actuator arm and spindle hub
pressed on the top of the shaft.

      The spindle motor consists of only two pieces, a permanent
magnet ring (15) positioned in the steel spindle hub (14) and a
stator (16) fixe...