Dynamic magnetic information storage or retrieval – Fluid bearing head support – Disk record
Reexamination Certificate
2000-05-02
2003-04-01
Korzuch, William (Department: 2653)
Dynamic magnetic information storage or retrieval
Fluid bearing head support
Disk record
Reexamination Certificate
active
06542333
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a magnetic head for use of a floppy disc drive (FDD) and a hard disc drive (HDD).
2. Prior Art
As an example of a conventional magnetic head, what is shown in
FIGS. 9
to
11
have been known.
In
FIGS. 9 and 10
, a magnetic head
1
is formed in general with an approximately rectangular slider
4
having rail portions
2
,
3
(hereinafter called as the first and the second rail one side of which slides on a magnetic recording medium (not shown)), an approximately rectangular opening
5
formed in the first rail
2
of the slider
4
, a front core
8
having an operation gap (a gap
6
for recording and reproducing and a gap
7
for erasing) which is sealed with a glass etc. to be filled in the hole
5
, a back yoke
10
made of a magnetic materials to form a head core
9
with the front core
8
by being connected to the front core
8
, a coil
11
for reproducing and a coil
12
for erasing coupled with the leg portions (the first, the second leg portions
23
,
25
).
Between the first rail
2
and the second rail
3
of the slider
4
, a groove
13
is formed.
The front core
8
is formed in general, as shown in
FIG. 11
, with a first core body
14
one side of which comprises a gap
6
for recording and reproducing, a second core body
15
which comprises gaps
7
for erasing which is connected to the first core body
14
, and that is configured approximately rectangular in such a manner as it can be inserted in the hole
5
.
In this type of the magnetic head
1
, in the hole
5
the front core
8
as apart of the head core
9
is inserted, the glass etc. is flown in the hole
5
and the front core
8
is sealed in the slider
4
, and glass is filled between the front core
8
and the slider
4
so as to avoid it from forming a gap. This is for preventing the dust etc. from entering to deteriorate any property when any gap is formed.
If the inner wall of the hole
5
and the side of the front core
8
are flat each other like the above structure, at the time when the front core
8
is deflected in the hole
5
, a gap between both becomes approximately tight, so that, the flowing of the glass becomes worse and the glass is insufficiently filled, and a trouble, in which a void not to be filled with glass is generated, occurs.
In order to prevent the glass from being insufficiently filled, as a method for a stable flowing of the glass, here is a magnetic head
1
, in which, as shown in
FIG. 12
, on all of the inner wall of the hole
5
(first, second, third, fourth inner walls,
30
a
,
30
b
,
30
c
,
30
d
), projections (first, second, third, fourth projections
31
a
,
31
b
,
31
c
,
31
d
) are provided to keep a certain gap there between and secure an easily controlled flowing of the glass.
However, when projections are provided on all inner wall of the hole as the magnetic head of
FIG. 12
, there has occurred a problem in which, since the front core
8
is displaced free in the hole
5
, it is difficult to make the front core
8
positioned properly.
In order to solve the above problem, the inventor has proposed a magnetic head shown in Japanese patent laid open No. Hei 10-154319. The magnetic head
1
shown in that publication is formed, as shown in
FIG. 13
, in such a manner as a height H
1
of the first projection
31
a
and the fourth projection
31
d
formed on the adjacent first inner wall
30
a
and the fourth inner wall
30
d
is settled lower than the height H
2
of the second projection
31
b
and the third projection
31
c
formed on the second inner wall
30
b
and the third inner wall
30
c
(H
1
<H
2
).
According to thus structured magnetic head
1
, the front core
8
is, at the time of sealing the glass flown, attracted by the first inner wall
30
a
and the fourth inner wall
30
d
due to the surface tension and aligned with the first and fourth inner wall
30
a
and
30
d
to be positioned properly.
Further, in this case, since on the first inner wall
30
a
and fourth inner wall
30
d
(the first projection
31
a
and the fourth projection
31
d
) are provided and between the first and fourth inner walls
30
a
,
30
d
and the front core
8
are kept with a given gap G
14
, the glass will flow appropriately in the G
14
and is adapted to be controlled in glass filling lack.
However, in the magnetic head shown in
FIG. 12
or
13
, since there are provided with the projections (the first, the second, the third, the fourth projections,
31
a
,
31
b
,
31
c
,
31
d
) on all of the inner walls of the hole
5
(the first, the second, the third, the fourth inner walls,
30
a
,
30
b
,
30
c
,
30
d
), there will be a problem in which any lack or crack around the projections has been apt to be generated.
That is, in the magnetic head shown in
FIG. 12
or
13
, the hole
5
of the slider
4
is formed using a convex pin type of mold. And, after molding the slider
4
, in accordance with some deflected amount (a deflected amount of the mold) due to the position and the inclination of the mold and the inclination at the time of extruding the mold, any internal stress is concentrated on the projection formed on the inner wall of the hole
5
and the corner portions at
4
corners, some breakages or cracks are apt to be generated. In this case, since there is a relation that as longer the distance from the center of the convex pin type of mold is, the larger the deflection amount of the mold is, a deflection amount of the short side (the first and the third inner walls
30
a
and
30
c
) becomes larger, which influences much against the short side, and the generation of the breakage or crack is outstanding at the short side (the first and the third inner walls
30
a
and
30
c
).
The above breakage and crack at the short side is led to the cause of a decrease of the reliability of the product, an increase of the defective rate of the product and a cost up for mass production, as a result, it has been a large obstacle for production.
Further, as a countermeasure against the breakage or crack at the short side, as shown in
FIG. 14 and 15
, by merely getting rid of the projection, as mentioned above, the short side wall and the side of the front core
8
become approximately tight, so that the gap between them is narrow to invite a lack of glass filling.
Further, the positioning of the front core
8
to the hole
5
at the time of inserting it to the hole
5
, it is preferable to carry out at high precision in order to secure good recording and reproducing. However, in the above conventional art, for example as shown in
FIG. 14
or
FIG. 15
, the front core
8
becomes inclined when being inserted in the hole
5
(for instance, refer to X axis of
FIG. 14
or
15
), which is apt to invite a generation of azimuth defect and has been no appropriately sufficient for the above demand.
The present invention has been made in the light of the above circumstances, the purpose thereof is to provide a magnetic head which can control the generation of any breakage or crack.
And, another purpose of the present invention is to prevent the glass from being filled insufficiently and increase the positioning precision of the front core at the time of being inserted in the hole.
According to a first aspect of the present invention, in a magnetic head which comprises a slider having a rail portion sliding on a magnetic recording medium, an approximately rectangular opening formed in the rail portion of the slider, a front core, one portion of which is inserted and sealed with a sealing agent, and having an operation gap, a back yoke which forms the head core with the front core and coils for recording, reproducing and erasing which are coupled with the leg portions of the back yokes, long side walls of 4 inner walls which form the hole have at least two stripes of projections extending in the coming through direction, and at least one of the two short side walls is inclined at a given angle against a vertical face normal to the long side walls.
According to a second aspect of the present inv
Iwakura Masayuki
Sano Akinobu
Beacham Christopher R
Korzuch William
Minebea Co. Ltd.
Oliff & Berridg,e PLC
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