Dynamic magnetic information storage or retrieval – Fluid bearing head support – Disk record
Reexamination Certificate
1999-01-15
2001-04-24
Heinz, A. J. (Department: 2652)
Dynamic magnetic information storage or retrieval
Fluid bearing head support
Disk record
C360S246600, C360S246800
Reexamination Certificate
active
06222703
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to magnetic heads and structures for supporting the same and, more particularly, to a magnetic head for reading from and writing to a rotated medium (magnetic disk) in an elevated state produced by an air flow occurring between the head and the medium, and to a supporting structure for such a magnetic head.
2. Description of the Related Art
Generally, an ordinary magnetic disk device that uses a flexible magnetic disk having a coercive force of 900 oersted (Oe) or below as a magnetic recording medium allows a relatively low rotational speed of 300 rpm. In this case, magnetic reading and writing is performed by causing the magnetic head to be in direct sliding contact with the magnetic disk.
However, with the advancement of high-density recording on the magnetic disk, magnetic disk devices which allow a high rotational speed (for example, 3000 rpm) of a magnetic disk and use a magnetic disk having a coercive force of more than 1500 Oe (hereinafter, such a magnetic disk will be referred to as a high-capacity magnetic disk) and a magnetic head having a narrow gap are available. Such a magnetic disk device will be referred to as a high-capacity magnetic disk device.
Since a high-capacity magnetic disk device allows a high rotational speed of the disk, the magnetic disk and the magnetic head used therein may easily be damaged when the magnetic head is caused to be in direct contact with the magnetic disk, as is done in a conventional magnetic disk device.
In this background, a high-capacity magnetic disk device is designed such that the magnetic head flies over the high-capacity magnetic disk due to an elevating force occurring as a result of a change in the course of an air flow caused by a relative speed between a slider surface of the magnetic head and the magnetic disk. Magnetic reading and writing is performed while a non-contact state is maintained.
FIGS. 1 through 5
show magnetic heads used in a high-capacity magnetic disk device according to the related art.
As shown in
FIGS. 1 and 2
, a magnetic head
1
according to the related art generally comprises a slider
2
and a magnetic head part
3
. The slider
2
holds the magnetic head part
3
and causes the magnetic head part
3
to float over a magnetic disk
6
.
The slider
2
has an air bearing surface forming an air bearing with respect to the magnetic disk
6
. A central groove
2
a
is provided on the center of the upper surface of the slider
2
. Referring to
FIG. 2
, the central groove
2
a
partitions the air bearing surface into a first air bearing surface
2
b
located to the right side and a second air bearing surface
5
located to the left side.
The magnetic head part
3
is located in the first air bearing surface
2
b
. The first air bearing surface
2
b
is also provided with a pair of slots
4
. The magnetic head part
3
for performing magnetic reading and writing is formed by sandwiching a gap member between thin plates of magnetic cores.
The slots
4
extend in a tangential direction of the magnetic disk
6
(in the X direction indicated in
FIG. 2
) and provides a vent to an air flow produced between the magnetic disk
6
and the first air bearing surface
2
b
. By providing a vent to the air flow produced between the magnetic disk
6
and the first air bearing surface
2
b
, an elevating force exerted on the magnetic head
1
is reduced. Thus, by providing the slots
4
, the elevating force with respect to the magnetic head
1
can be controlled.
As described above, the second air bearing surface
5
is formed to the left of the central groove
2
a
. Like the first air bearing surface
2
b
, the second air bearing surface
5
also produces a force for elevating the magnetic head
1
.
FIG. 3
is a lateral sectional view taken from a position of disk insertion. As shown in
FIG. 3
, a pair of magnetic heads
1
are supported so as to be opposite to each other. The elevating force produced due to the presence of the second air bearing surface
5
provides a force to push the magnetic disk
6
toward the first air bearing surface
2
b
(that is, the magnetic head part
3
) of the opposite magnetic head
1
. Accordingly, the second air bearing surface
5
also acts as a pressure pad for pressing the magnetic disk
6
toward the opposite magnetic head
1
.
As described above, the slots
4
are formed in the first air bearing surface
2
b
. The slots
4
provide a vent to the air flow produced between the magnetic disk
6
and the first air bearing surface
2
b
, thus reducing an elevating force exerted on the magnetic head
1
. As a result of this, the rotated magnetic disk
6
between the pair of magnetic heads
1
is deformed such that it is warped toward a gap part
3
a
of the magnetic head part
3
due to a negative pressure generated in the slot
4
and due to a pressure generated due to the presence of the second air bearing surface
5
as a result of a change in the course of the air flow. With this construction, it is ensured that a magnetic reading and writing process with respect to the magnetic disk
6
is properly performed using the floating magnetic head
1
.
A description will now be given, with reference to
FIGS. 4 and 5
, of how the magnetic head
1
faces the magnetic disk
6
.
FIGS. 4 and 5
are views of the magnetic head
1
performing a magnetic reading and writing process, taken in a radial direction (Y direction) of the magnetic disk
6
.
FIG. 4
shows a state where the magnetic disk
6
approaches the magnetic head
1
in a normal profile, that is, with a normal magnitude of clearance from the magnetic disk
6
.
As shown in
FIG. 4
, a pair of slots
4
are formed in the first air bearing surface
2
b
in which the magnetic head part
3
is formed. Referring also to
FIG. 2
, the slots
4
are formed along the entire length of the first air bearing surface
2
b
(that is, in the X direction shown in
FIG. 4
) so as to extend from a leading edge
7
to a trailing edge
8
(an edge of the magnetic head
1
at which the magnetic disk
6
leaves the magnetic head
1
). Therefore, reduction in the elevating force due to the presence of the slots
4
is produced over the entire extent of the length of the first air bearing surface
2
b
.
Accordingly, even when the magnetic disk
6
approaches the magnetic head
1
in a normal profile, a distance H between the magnetic disk
6
and the leading edge
7
at an entrance of a space over the magnetic head
1
according to the above construction is smaller than the corresponding distance in a construction in which the slots
4
are not provided.
With such a construction, the magnetic disk
6
is maintained in close proximity to the magnetic head part
3
as a result of the reduction in the elevating force caused by the slots
4
, thus providing a proper magnetic reading and writing performance.
FIG. 5
shows a state where the magnetic disk
6
approaching the magnetic head
1
is lower than the magnetic disk
6
shown in FIG.
4
. Such a small-clearance approach results from inherent flexibility of the magnetic disk
6
or an error in the configuration of the magnetic disk
6
occurring in the process of fabrication.
When the magnetic head
1
approaches the magnetic disk
6
with a small clearance from the magnetic disk
6
, the distance H is reduced to such an extent that the magnetic disk
6
may come into contact with the leading edge
7
so that the magnetic disk
6
or the leading edge
7
may be damaged.
Summary of the Invention
Accordingly, an object of the present invention is to provide a magnetic head and a structure for supporting the same in which the magnetic reading and writing performance is properly maintained and contact between a medium and a slider is reliably prevented.
The aforementioned objects can be achieved by a magnetic head characterized by comprising: a first magnetic head part for performing a reading and writing process on a first flexible medium; a second magnetic head part for performing a reading and writing proce
Kudo Norikazu
Osaka Tomohiko
Heinz A. J.
Ladas & Parry
Mitsumi Electric Co. Ltd.
LandOfFree
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