Disk spacer in a disk drive system

Details Disk spacer in a disk drive system Disk spacer in a disk drive system

2002-02-20

2004-06-22

Davis, David (Department: 2652)

Dynamic magnetic information storage or retrieval

Record transport with head stationary during transducing

Disk record

Reexamination Certificate

active

06754040

ABSTRACT:

TECHNICAL FIELD
This invention relates to mechanical spacers between disks and disk clamps in disk drive systems.
BACKGROUND ART
Disk drives are an important data storage technology, which include several crucial components. Disk drive read-write heads directly communicate with a disk surface containing the data storage medium over a track on the disk surface. This invention involves improving the ability to position at least one read-write head over the track on the disk surface.
FIG. 1A
illustrates a typical prior art high capacity disk drive
10
including actuator arm
30
with voice coil
32
, actuator axis
40
, suspension or head arms
50
-
58
with slider/head unit
60
placed among the disks
12
.
FIG. 1B
illustrates a typical prior art high capacity disk drive
10
with actuator
20
including actuator arm
30
with voice coil
32
, actuator axis
40
, head arms
50
-
56
and slider/head units
60
-
66
with all but one disk
12
removed as well as including spindle motor
80
.
Since the 1980′s, high capacity disk drives
10
have used voice coil actuators
20
-
66
to position their read-write heads over specific tracks. The heads are mounted on head sliders
60
-
66
, which float a small distance off the disk drive surface when in operation. Often there is one head per head slider for a given disk drive surface. There are usually multiple heads in a single disk drive, but for economic reasons, usually only one voice coil actuator.
Voice coil actuators are further composed of a fixed magnet actuator
20
interacting with a time varying electromagnetic field induced by voice coil
32
to provide a lever action via actuator axis
40
. The lever action acts to move head arms
50
-
56
positioning head slider units
60
-
66
over specific tracks with speed and accuracy. Actuator arms
30
are often considered to include voice coil
32
, actuator axis
40
, head arms
50
-
56
and head sliders
60
-
66
. Note that actuator arms
30
may have as few as a single head arm
50
. Note also that a single head arm
52
may connect with two head sliders
62
and
64
.
FIG. 2
illustrates an exploded schematic view of a disk drive
10
including disk
12
separated by spacer
84
from disk
14
as found in the prior art.
Disk drive
10
also includes a printed circuit board assembly
120
, a disk drive base
100
, a spindle motor
80
, a disk
12
, a voice coil actuator
30
, a disk clamp
82
and a disk drive cover
110
.
FIG. 3A
illustrates a disk spacer
84
as in
FIG. 2
with an emphasis on its outer surface, which is essentially cylindrical, as found in the prior art.
A spacer
84
may include screw holes, which are not relevant to the invention and will not be illustrated nor discussed hereafter.
FIG. 3B
illustrates a typical prior art situation regarding the flow of air between disks
12
and
14
separated by disk spacer
84
while spinning in a disk drive.
Spindle motor
80
powers the rotating disk assembly including disks
12
and
14
, as well as disk spacer
84
and disk clamp
82
. To insure mechanical stability, all members of the rotating disk assembly are required to be symmetric about the axis of rotation for the assembly. This has lead prior art disk spacers
84
to have smooth cylindrical walls facing the air gap between disks
12
and
14
.
The outer wall of at least disk spacer
84
is cylindrical. In many prior art disk systems, the outer walls of spindle motor
80
and disk clamp
82
are also cylindrical.
It should be noted that while the prior art disk spacers
84
address the requirements known in the prior art, there are some problems with these devices.
FIG. 3C
illustrates the effect of smooth outer walls for disk spacer
84
, spindle motor
80
and disk clamp
82
upon the flow of air in the air cavity around disks
12
and
14
, as found in the prior art.
In each of the inner regions
140
near disk spacer
84
, as well as spindle motor
80
and disk clamp
82
, the inventors have found that the air is nearly stationary, particularly in region
142
. This region
142
is a zone dominated by the solid body motion of the cylindrical outer wall. This region of stationary air allows particles carried in the air to adhere to the surfaces of disks
12
and/or
14
. These particles cause media failures for the disk surfaces of inner regions
140
to be much higher than outside these inner regions
140
. What is needed is a way of reducing particle adherence to these inner regions
140
so as to reduce data failures in these regions.
SUMMARY OF THE INVENTION
The inventors have found that by changing the outer wall shape of at least the disk spacer, the air flow of the relevant inner region is disrupted, causing particulate adhesion to be minimized. The air flow disruption acts to blow more air through the inner region, effectively moving particles away from the inner region rather than retaining these particles. The inventors call disk spacers with outer wall shapes disrupting the flow of air in the inner region, screw-type spacers. Note that the invention also relates to the outer wall of disk clamps.
Mass distribution in a screw-type spacer is symmetrical about the axis of rotation of the rotating disk assembly to which the screw-type spacer belongs. This mass distribution helps minimize mechanical vibration when the rotating disk assembly is in operation within its disk drive.
The outer wall shapes will be called blades herein. The invention includes blades of many shapes, including, but not limited to, rectangular prisms oriented with respect to the radius from the axis of rotation, as well as non-rectangular shapes such as triangular prisms providing a symmetric mass distribution for the screw-type spacer about the axis of rotation.
The invention includes not only screw-type spacers, but also the method of making disk drives using screw-type spacers and those disk drives as a product of the manufacturing process. The invention includes the method of operating the screw-type spacer to blow away particles from the inner region about the screw-type spacer and neighboring disks.
Note that a disk drive may include more than one screw-type spacer, each blowing particles away from the inner region surrounding itself.
These and other advantages of the present invention will become apparent upon reading the following detailed descriptions and studying the various figures of the drawings.


REFERENCES:
patent: 4922354 (1990-05-01), Edwards
patent: 5006942 (1991-04-01), Brooks et al.
patent: 5239431 (1993-08-01), Day et al.
patent: 5504638 (1996-04-01), Kinoshita et al.
patent: 5615067 (1997-03-01), Jabbari et al.
patent: 6201661 (2001-03-01), Korkowski
patent: 6285525 (2001-09-01), McCutcheon et al.

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