Dynamic magnetic information storage or retrieval – Head mounting – Disk record
Reexamination Certificate
1998-07-24
2004-12-14
Davis, David (Department: 2652)
Dynamic magnetic information storage or retrieval
Head mounting
Disk record
Reexamination Certificate
active
06831814
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to flexure designs in disk drives. More particularly, the present invention provides a flexure design that can be used advantageously in a ramp load/unload disk drive using a sub-ambient slider device.
BACKGROUND OF THE INVENTION
Disk drives are commonly used in workstations, personal computers, laptops and other computer systems to store large amounts of data in a form that can be made readily available to a user. In general, a disk drive comprises a magnetic disk that is rotated by a spindle motor. The surface of the disk is divided into a series of data tracks. The data tracks are spaced radially from one another across a band having an inner diameter and an outer diameter.
Each of the data tracks extends generally circumferentially around the disk and can store data in the form of magnetic transitions within the radial extent of the track on the disk surface. An interactive element, such as a magnetic transducer, is used to sense the magnetic transitions to read data, or to transmit an electric signal that causes a magnetic transition on the disk surface, to write data. The magnetic transducer includes a read/write gap that contains the active elements of the transducer at a position suitable for interaction with the magnetic surface of the disk. The radial dimension of the gap fits within the radial extent of the data track containing the transitions so that only transitions of the single track are transduced by the interactive element when the interactive element is properly centered over the respective data track.
As known in the art, the magnetic transducer is mounted by a head structure to a rotary actuator arm and load beam and is selectively positioned by the actuator arm over a preselected data track of the disk to either read data from or write data to the preselected data track of the disk, as the disk rotates below the transducer. The actuator arm is, in turn, mounted to a voice coil motor that can be controlled to move the actuator arm across the disk surface.
The head structure also includes a slider having an air bearing surface that causes the transducer to fly above the data tracks of the disk surface due to fluid currents caused by rotation of the disk. Thus, the transducer does not physically contact the disk surface during normal operation of the disk drive to minimize wear at both the head and disk surface. The amount of distance that the transducer flies above the disk surface is referred to as the “fly height.” It is a design goal to maintain the fly height of the head at an even level regardless of the radial position of the head.
The magnetic transducer typically resides at the trailing edge of the slider body. In a contact start stop (CSS) operation, the slider rests on the surface of the disk when the disk is not spinning and momentarily slides upon the surface of the disk as the disk spins up until the slider eventually flies above the surface of the disk. When the disk stops spinning, the slider once again rests on the surface of the disk. Several problems are seen with CSS systems. First, the slider contact with the disk can cause damage to the slider, the disk, or both. Also, there may exist “starting friction” (also known as “stiction”) between the slider and the disk, which may also cause damage to the slider, the disk, or both.
One solution in the art is ramp loading/unloading. In this procedure, it is intended that the slider never rest upon the disk. Instead, when no reading or writing operation is needed, the load beam (to which the slider is connected via a flexure) is rotated away from the recordable area of the disk to a point where it will contact the lower portion of an inclined ramp. The load beam is further rotated so that it will move up the incline of the ramp and away from the surface of the disk. As the load beam is moved away from the disk, the flexure as well as the slider are likewise urged away from the spinning disk.
Ramp unloading may have a negative affect on the flexure, especially when a so-called “negative-pressure” or “sub-ambient” slider is being used. An example of a known negative pressure slider is shown in FIG.
1
. The side of the slider which faces the disk includes at least first and second rails
10
and
12
with a cross beam
14
or similar structure connecting the rails at the leading edge of the slider. The air flow resulting from the spinning disk passes over the leading edge of the slider and the cross beam
14
and will cause an area of negative pressure (i.e., pressure less than 1 atmosphere) in an area
16
between the first and second rails
10
and
12
and cross beam
14
. This negative pressure causes the slider to fly lower to the spinning disk which allows for a higher recording density and larger disk capacity.
Referring to
FIG. 2
, a flexure that is known in the art is shown. Flexure
50
includes a main body
51
having a near end
52
. First and second “outriggers”
53
a
and
53
b
are provided which connect at a distal end
54
of the flexure. A tab
55
is provided, extending from the distal end
54
of the flexure
50
via a neck portion
56
. The slider (e.g., the slider of
FIG. 1
) is attached to the tab
55
of the flexure
50
so that the leading edge of the slider faces the near end
52
of the flexure and the trailing edge of the slider faces the distal end
54
of the flexure.
Referring to
FIG. 3
, a side view of the flexure
50
is shown attached to a load beam
60
and slider
65
is attached to the tab portion of flexure
50
. In this example a bubble
67
is provided on the side of the slider facing away from the disk surface. The bubble
67
, outriggers
53
a,
53
b,
tab
55
and neck portion
56
contribute to allowing the slider
65
to pitch and roll relative to the moving disk
68
. As shown in
FIG. 3
, the leading edge of the slider
65
pitches up slightly contributing to the slider's ability to fly over the moving disk. When using this flexure in a ramp load/unload drive, the movement of the load beam away from the disk surface will cause the flexure to move away from the moving disk surface as well. As the flexure moves away from the disk surface, it pulls on the slider
65
at its trailing edge (as indicated by the upward pointing arrow). This causes the slider to pitch forward. The negative pressure area of the slider, however, is maintained. Accordingly, as the load beam continues to move up the ramp and away from the disk surface, the slider maintains its negative pressure attraction to the moving disk surface (as indicated by the downward pointing arrow) causing the flexure to bend, as shown in FIG.
3
. The flexure will continue to stretch and bend until the slider is eventually pulled away from the disk surface. This stretching can cause the flexure to mechanically deform which can have deleterious effects on the flexure and its ability to control the pitch and roll of the slider.
In view of the above, there is a need for an improved flexure design that avoids these problems.
REFERENCES:
patent: 4280156 (1981-07-01), Villette
patent: 4399476 (1983-08-01), King
patent: 4616279 (1986-10-01), Poorman
patent: 4896233 (1990-01-01), Yamada
patent: 4922356 (1990-05-01), Yamaguchi et al.
patent: 5115363 (1992-05-01), Khan et al.
patent: 5530605 (1996-06-01), Hamaguchi et al.
patent: 5617274 (1997-04-01), Ruiz
patent: 5630948 (1997-05-01), Ueda et al.
patent: 5659448 (1997-08-01), Shimizu et al.
patent: 6115221 (2000-09-01), Utsunomiya
patent: 9-147510 (1997-06-01), None
Davis David
Kenyon & Kenyon
SAE Magnetics (H.K. ) Ltd.
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