Dynamic magnetic information storage or retrieval – Fluid bearing head support – Disk record
Reexamination Certificate
2001-01-10
2003-03-04
Tupper, Robert S. (Department: 2652)
Dynamic magnetic information storage or retrieval
Fluid bearing head support
Disk record
C360S235200, C360S235600, C360S236100, C360S236200, C360S236300, C360S236600
Reexamination Certificate
active
06529346
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic head slider, which flies above a magnetic recording medium with a minute spacing therebetween, for writing and reading magnetic information. More particularly, the invention relates to a magnetic head slider in which adhesion of the surface of a slider body facing a recording medium on the side of a magnetic disk to the magnetic disk can be further decreased without adversely affecting the flying.
2. Description of the Related Art
A conventional magnetic disk unit as shown in
FIG. 10
is known for magnetic recording apparatuses for computers.
In this magnetic disk unit, a magnetic head slider
82
is disposed opposite to a magnetic disk
81
which is rotatably provided, and the magnetic head slider
82
is supported by an arm
84
with a triangular leaf spring
83
therebetween. The magnetic head slider
82
can be moved to a predetermined position in the diametric direction of the magnetic disk
81
due to the rotation of the arm
84
around a rotation center
84
a.
In the magnetic disk unit having the structure shown in
FIG. 10
, when the magnetic disk
81
is stopped, the bottom surface of the magnetic head slider
82
is gently pressed to the magnetic disk
81
by the elastic force of the leaf spring
83
which supports the magnetic head slider
82
. When the magnetic disk
81
is rotated, the magnetic head slider
82
flies above the magnetic disk
81
at a predetermined height using the airflow caused by the rotation. When the rotation of the magnetic disk
81
is stopped, the magnetic head slider
82
, which has been flying, comes into contact with the magnetic disk
81
again and stops. Magnetic information is read and written from and into a magnetic recording layer of the magnetic disk
81
while the magnetic head slider
82
is flying. Such a series of operations are usually referred to as CSS (Contact-Start-Stop) operations.
FIG. 11
shows the flying state of a 2-rail type magnetic head slider
82
, which is widely used. On the bottom surface of the magnetic head slider
82
, a groove (not shown in the drawing) is formed in the center, and side-rails
86
are formed on both sides with the groove therebetween. An inclined area
86
a
is formed on the lower surface of the tip of each side-rail
86
. As the air inflow occurs through the inclined area
86
a
as indicated by arrows A in
FIG. 11
, the bottom surface of the side-rail
86
of the magnetic head slider
82
acts as a positive pressure-generating section so that the magnetic head slider
82
flies. In each side-rail
86
, the width of the magnetic head slider
82
on the front side (the air inflow side
82
a
) is set to be broader than the width on the rear side (the air outflow side
82
b
).
A structure of a magnetic head slider is also known in which, as shown by the double-dotted chain line in
FIG. 11
, a negative pressure groove
86
b
is formed in the bottom surface of the side-rail
86
, and by balancing negative pressure generated by the negative pressure groove
86
b
and positive pressure generated by the side-rails
86
, flying performance is stabilized.
When the magnetic head slider
82
flies, air flows toward the bottom side of the magnetic head slider
82
through the inclined area
86
a
, and in the case in which the negative pressure groove
86
b
is further formed, since negative pressure is generated at the rear of the magnetic head, the magnetic head slider
82
flies while tilting at a very small angle with the air inflow side
82
a
being lifted. Generally, this angle of tilt is referred to as the pitch angle (&agr;: usually, approximately 100 &mgr;Rad).
In the magnetic head slider
82
having the structure as described above, the slider
82
comes into sliding contact with the magnetic disk during starting and during stopping of the magnetic disk
81
. Therefore, in order to avoid abrasion and wear on the surface of the magnetic disk, a protective film may be formed on a recording layer of the magnetic disk
81
, and a lubricating layer may further be formed on the protective film.
In the magnetic head slider
82
having the structure described above, in view of magnetic recording, since it is advantageous to bring a magnetic gap G of the magnetic head slider
82
as close to the magnetic recording layer of the magnetic disk
81
as possible, the flying height of the magnetic head slider
82
is preferably decreased as much as possible. As the recording densities of the magnetic disk units are increased and magnetic disk units are miniaturized, there are trends to further decrease the flying height (the amount of space between the magnetic head slider
82
and the magnetic disk
81
) of the magnetic head slider
82
. When the flying height is decreased, the surface roughness of the magnetic disk
81
must be decreased as much as possible in order to avoid contact between the magnetic disk
81
and the magnetic head slider
82
in the flying state. However, during starting or during stopping of the magnetic disk
81
, the smoother the surface of the magnetic disk
81
, the greater the contact area between the magnetic disk
81
and the magnetic head slider
82
, and the slider
82
easily adheres to the magnetic disk
81
, thus increasing adhesion torque.
If the adhesion torque is increased, the load during the starting of the motor for rotating the magnetic disk
81
is increased, and a magnetic head element provided on the arm
84
or the slider
82
and the recording layer of the magnetic disk are easily damaged when the magnetic disk
81
starts rotating.
In order to solve such problems, a magnetic head slider was proposed in which, as shown in
FIG. 12
, by forming a crown on the surface of a magnetic head slider
82
facing a recording medium on the side of a magnetic disk
81
, and also by forming a crown on each side-rail
86
, the contact area between the magnetic head slider
82
and the magnetic disk
81
is decreased. A magnetic head slider was also proposed in which, as shown in
FIG. 13
, protrusions
89
a
and
89
b
are provided on each side-rail
86
of a magnetic head slider
82
in the longitudinal direction of the side-rail
86
, and thus the contact area between the magnetic head slider
82
and the magnetic disk
81
is decreased. Additionally,
FIGS. 12 and 13
are side views which show the flying states of the individual magnetic head sliders.
In the magnetic head slider, as described above, because of the demands for increasing the recording density of the magnetic disk unit and for miniaturizing the magnetic disk unit, the flying height of the magnetic head slider
82
tends to be decreased, and the pitch angle is accordingly also decreased.
However, in the conventional magnetic head slider provided with the crown as shown in
FIG. 12
, if the recording density is increased and the flying height is decreased, the flatness of the magnetic recording medium is increased and the magnetic head slider easily adheres to the magnetic recording medium, and thus the effects anticipated from the provision of the crown are not easily obtained, depending on the pattern of the surface facing the recording medium, i.e., the shape and width of each side-rail
86
, and the shape and width of the groove between the side-rails
86
.
In the conventional magnetic head slider provided with the protrusions
89
a
and
89
b
as shown in
FIG. 13
, if the pitch angle is decreased, in the flying state, the protrusion
89
b
near the air outflow side
82
b
protrudes toward the magnetic disk
81
more than the magnetic gap G, and thus it is not possible to decrease the flying height.
Consequently, it may be envisioned that the position of the protrusion
89
b
should be shifted from near the air outflow side
82
b
to the air inflow side
82
a
by a length L
1
, as indicated by the broken line in FIG.
13
. However, when the pitch angle is small, the position of the protrusion
89
b
must be shifted to the air inflow side
82
a
by a considerable amount, and even in such a case, the area
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Tupper Robert S.
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