JPH11238213A - Magnetic head with air lubricating surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic head with an air lubricating surface of a negative pressure type whose roll is small and which is capable of constantly floating across inner/outer peripheries, even when an air flow made by the rotation of a disk flows in with a skew angle with respect to the magnetic head. SOLUTION: The magnetic head with the air lubricating surface is provided with two side rails 12 varying widths along both side edges of the opposed surface of a magnetic recording medium and tilting parts or level difference parts 122 provided on the flowing tip side of each side rail 12. The widths of the side rails 12 are largest at their flow-in tips, and smallest-width parts 123 are retreated to the inside of the air lubricating surface. In addition the smallest-width parts 123 are nearly parallel and are oblique with respect to the longitudinal direction of a slider 1 to have inclination with respect to the side edges.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head used in a magnetic recording device such as an HDD, and more particularly to a magnetic head having an air lubricating surface for floating by rotation of a magnetic recording medium. The present invention relates to a magnetic head having an air lubricating surface capable of preventing the slider from tilting due to the direction of the accompanying air flow.

[0002]

2. Description of the Related Art A magnetic head used in a magnetic recording apparatus such as an HDD has an air lubricated surface of a slider on a surface facing a magnetic recording medium, and side rails are provided along both side edges thereof. . A magnetic head is provided at the rear end of the side rail or at the rear end of the pad at the center rear end of the two side rails. The air flow accompanying the rotation of the magnetic recording medium flows along the side rail surface of the air lubrication surface, so that the magnetic head flies with the slider with respect to the recording medium.

It is necessary to keep the distance between the recording medium and the magnetic head constant, but if the flying height changes, the distance also changes. However, the speed of the air flow by the recording medium changes depending on its radial position. On the outside of the air lubrication surface of the magnetic head, that is, on the outer periphery of the disk, the peripheral speed of rotation is high and the flow of the air flow is fast. On the inner side of the air lubrication surface, that is, on the inner peripheral side of the disk, the peripheral speed of rotation is low. The flow is slow. For this reason, the flying height of the flying slider changes between the inner circumference side and the outer circumference side of the disk. Further, since the flying height varies between the two side rails of the flying slider, the slider is inclined in the width direction (called a roll). Therefore, a negative pressure slider that generates a negative pressure on a part of the air lubrication surface of the slider is used. As the negative pressure slider, as shown in FIG. 14 as viewed from the surface facing the magnetic recording medium, two side rails 31 provided along both side edges of the air lubrication surface of the slider 30; A cross rail 32 connecting the two side rails 31 is provided at the inflow end, and a cavity 3 is formed in an air lubrication surface surrounded by the two side rails 31 and the cross rail 32.
3 are provided. The air flow that has passed over the side rail or cross rail from the inflow end expands at the cavity 33 to generate a negative pressure. The levitation force of the slider 30 increases with the flow rate of the air flow, that is, the peripheral speed of rotation. However, in the case of a negative pressure slider, the negative pressure also increases with the peripheral speed of rotation, and the positive pressure and the negative pressure cancel each other out. Reduces the peripheral speed dependence of the rotation of the flying height.

[0004]

By using a slider for the magnetic head as a negative pressure slider, the flying height can be made substantially constant with respect to the peripheral speed of rotation of the recording medium. In this case, the side rails of the air lubrication surface are arranged in parallel to the rotation direction. In an actual HDD, a magnetic head is attached to the tip of a head arm that pivots around a rotation axis provided outside a recording medium, and the magnetic head moves in the radial direction of the disk. For this reason, when the magnetic head is located near a specific radial position on the disk, the side rail of the air lubrication surface is parallel to the rotation direction of the disk, but when the magnetic head is near the center or outer periphery of the disk. In this case, the side rails of the air lubrication surface are inclined with respect to the rotation direction of the disk, and face each other at an angle. This angle is called a skew angle. When the skew angle is increased, the working distance of the air being compressed on the side rail is shortened, the levitation force is reduced, and the flying height of the slider is also reduced. On the other hand, a negative pressure is generated by the air expanding behind the side rails on the windward side, and a stronger suction force acts on the rails on the windward side.
There is a problem that the roll of the magnetic head becomes large.

According to the present invention, a negative pressure type air lubricating surface which is small in roll and can float constantly over the inner and outer peripheries even when the air flow due to the rotation of the disk flows into the magnetic head with a large skew angle. The purpose of the present invention is to provide a magnetic head having the following characteristics.

[0006]

A magnetic head having an air-lubricated surface according to the present invention comprises two side rails whose width changes along both side edges of a magnetic recording medium facing surface, and an inflow end of each side rail. The side rail has a slope portion or a step portion provided on the side, and the side rail is characterized by being receded inside the slider at a widest portion and a narrowest portion at an inflow end.

In the magnetic head having an air-lubricated surface according to the present invention, it is preferable that the narrowest portion of the side rail is substantially parallel and oblique to the longitudinal direction of the slider. . Further, it is preferable that the side rails project from the air lubrication surface by 6 μm or less.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a magnetic head having an air lubricated surface according to the present invention will be described in detail with reference to the drawings. FIG.
FIG. 3 is a diagram (rear view) of a magnetic head having an air lubrication surface according to the present invention as viewed from a surface facing a recording medium. FIG. 2 is a side view of a magnetic head having an air lubrication surface. FIG. 3 is an explanatory diagram of the size and skew angle of the notch provided in the side rail. FIG. 4 is a graph showing the standardized levitation force (arbitrary unit) and the skew angle showing the size of the notch provided in the side rail as parameters. It is a graph which shows the relationship of (deg). FIG. 5 is an illustration of the air lubrication surface of the magnetic head having the air lubrication surface of the present invention, in which the narrowest part of the side rail is offset from the side edge. FIG. FIG. 7 is a contour diagram obtained by simulating the pressure distribution on the air lubricated surface of the magnetic head having the magnetic head.
8 is a graph showing the pressure distribution in the cross-sections A, B, and C with respect to the distance in the width direction. FIG. 8 is a similar graph when the offset amount is 0.25 mm, and FIG.
It is a graph which shows the skew angle dependence of the roll angle of a slider at the time of changing to 25 mm. FIG. 10 is an explanatory view of the air lubrication surface of the magnetic head having the air lubrication surface of the present invention, in which the narrowest part of the side rail is inclined with respect to the side edge. 13 each have a tilt angle of 0
10, 2.4 ° and 4.8 ° in FIG.
It is a graph which shows the pressure distribution in E and F with respect to the width direction distance.

In the slider 1 of the magnetic head having an air lubrication surface of the present invention, two side rails 12 are provided along the air lubrication surface 11 shown in FIG. Each of the side rails 12 has a widest portion 121 on the inflow end side, and an inclined portion or a step portion 12 is provided at the tip of the widest portion 121.
Two. Further, the side rail 12 has a narrowest portion 123 substantially at an intermediate portion, and the narrow portion 123 retreats inward from the side edge (this retreat amount is shown as an offset amount 124 in FIG. 5). ing. The narrowest portion 123 is substantially parallel, is oblique to the longitudinal direction of the slider 1, and has an inclination angle with respect to the side edge. This inclination angle is preferably about 2 to 10 °. The narrowest portion 123 is preferably 5% or more and 40% or less of the length of the side rail 12 in length, and the width of the narrowest portion 123 is 5% of the width of the side rail 12.
0% or less, preferably 25% or less.

A pad 13 is provided at an outflow end of the air lubrication surface 11, and a magnetic head 14 having a magnetoresistive element is attached to a rear end surface of the pad 13. It is also possible to extend the side rail 12 to the rear end of the slider 1 and provide a magnetic head at the outflow end. The magnetic head having the air lubrication surface is installed so as to face the magnetic recording medium 2 of a magnetic disk such as an HDD, and the air flow 17 lifts the air lubrication surface 11 with the rotation of the magnetic disk, so that the air lubrication surface is cleaned. The slider 1 of the magnetic head is lifted with respect to the recording medium 2. The air flow 17 acts on the side rail surface to generate a levitation force. By projecting the side rail 12 from the air lubrication surface by 6 μm or less, a negative pressure region 15 is formed in a shaded portion surrounded by the widest portion 121 and the narrowest portion 123 of the side rail 12. If the height of the side rails 12 exceeds 6 μm, the negative portions will not function as the negative pressure regions 15.
A step having a height of μm or less is desirable.

In the magnetic head having an air-lubricated surface according to the present invention, the negative pressure region 15 is provided behind the widest inflow end portion 121 of the side rail 12 to reduce the peripheral speed dependency of the flying height. ing. Further, since a part of the side rail 12 is cut away and the narrowest portion 123 is present, a change in the area of action where air is compressed with respect to the skew angle is small, and the skew angle dependency of the flying height is reduced. You. Further, since the narrowest portion 123 of the side rail 12 is receded inward from the side edge of the slider, a negative pressure region is created on both leeward sides of the two side rails 12 even when the skew angle is large. Is difficult to roll. In addition, by giving the narrow angle to the narrow portion 123, the positive pressure for compensating the negative pressure generated for the skew in a specific direction is increased,
You can control the roll.

The side rail 12 has the narrowest portion 12
By providing 3, the inflow direction of the airflow 17 (called the skew angle, the front of the side rail 12 is 0 °, the inflow from the left as viewed from the side rail 12 is positive, and the inflow from the right is negative. 4) shows how the levitation force of the air-lubricated surface changes due to the change in the above-described calculation by simulation using the modified Reynolds equation. FIG. 3 shows a state of the notch when this simulation is performed. Here, by attaching the notch 125 to the side rail 12 by 20% of the entire length, the narrowest portion 12 is formed.
The width of 3 is 100%, 50%, 25%,
10%. The air flow 17 flows in from the left side of the figure. In FIG. 4, the vertical axis is a value (arbitrary unit) normalized by the levitation force at skew 0, and the horizontal axis is the skew angle (de).
g. ), The narrowest part 1 of the side rail 12
23 is shown as a parameter. As is clear from this figure, the rail width is 50% and 25% as compared with the case of the straight side rail without cutout (100%).
% And 10%, the skew dependence of the levitation force was reduced. Providing the minimum width portion on a part of the rail and limiting the flow inflow at skew 0 is effective in reducing the skew dependency of the levitation force.
From the above, the width of the narrowest portion 123 is preferably 50% or less of the width of the side rail 12, and more preferably 25% or less. The length thereof is preferably 5% or more and 40% or less of the length of the side rail 12.

In the magnetic head having an air lubricating surface according to the present invention, the narrowest portion 123 provided on the side rail 12 is provided.
Consider the effect of retracting inward from the side edge of the slider. 5 air lubricated surface 11 2 mm long and 1.6 mm wide
The side rail 12 is provided with a portion 123 having the narrowest width, and this portion 123 is offset from the side edge by an offset amount 1.
It has been retreated by 24.

FIG. 6 shows a contour map obtained by simulation of a pressure distribution when air flows at a skew angle of 20 ° from the lower left direction of the air lubrication surface with the offset amount set to 0. Here, FIG. 7 is a graph showing the pressure distribution along the lines of the cross sections A, B, and C with respect to the distance in the width direction.
At the offset 0, the pressure is low on the left side (lower side in FIG. 6) of the graph corresponding to the windward side, and it can be seen that the negative pressure is superior. For this reason, the rail on the windward side sinks, and the slider 1 tilts (rolls) in the width direction. However,
The offset amount is set to 0.25 mm, and the narrowest part 1
When the slider 23 is retracted inside the slider 1, the peak pressure on the left side increases as shown in the graph of FIG. As a result, the left and right imbalance of the slider 1 is improved as a whole.

The offset amount 124 is from 0 to 0.25 mm
FIG. 9 shows the results obtained by examining the skew dependence of the roll angle of the slider 1. As the narrowest portion 123 recedes into the slider, the change in roll angle due to skew decreases. That is, even if the skew increases, the roll can be controlled by retracting the narrowest portion 123 inside. From the above, the length 2 mm and the width 1.6 mm studied here
In the slider described above, the offset amount is 0.1 mm or more, preferably 0.25 mm or more.

The narrowest part 12 of the side rail 12
3 is oblique to the longitudinal direction of the slider,
The effect of having an inclination angle with respect to the side edge will be discussed. In the air lubrication surface 11 shown in FIG.
2 has the inclination angle θ with respect to the side edge, and assuming that air flows in at a skew angle of 20 °, the pressure distribution in the cross sections D, E, and F is represented by the width direction distance. 11, 12 and 13 are graphs in which the inclination angles θ are 0 °, 2.4 ° and 4.8 °, respectively. In the case of the inclination angle of 0 °, the pressure on the rail on the left side of FIG. 11, that is, on the lower side (upwind) of the slider 1 in FIG. 10 is low, but as the inclination angle increases to 2.4 ° and 4.8 °, the wind The pressure on the upper rail is increasing and the pressure on the leeward rail is decreasing. From this, the rail 12
By inclining the narrowest portion 123 of the slider with respect to the longitudinal direction of the slider 1, it is possible to increase the positive pressure formed on the windward rail that tends to sink when skew occurs, thereby preventing the occurrence of rolls. Can be. If this inclination angle is too small, there is no effect, and if it is too large, the pressure on the leeward side increases and the pressure on the leeward side decreases, so that 2 to 10 °
Good degree.

[0017]

As described above in detail, in the magnetic head having an air-lubricated surface according to the present invention, the narrowest portion of the side rail is provided after the widest inflow end portion of the side rail. By retreating the inside of the air-lubricated surface, the roll caused by the skewed air flow can be reduced. Further, by providing the narrowest portion at an angle, a balanced positive pressure can be generated on the left and right rail surfaces, and furthermore, roll can be prevented.

[Brief description of the drawings]

FIG. 1 is a view (rear view) of a magnetic head having an air lubricated surface according to the present invention as viewed from a surface facing a recording medium.

FIG. 2 is a side view of a magnetic head having an air lubrication surface.

FIG. 3 is an explanatory diagram of a size of a notch provided in a side rail and a skew angle.

FIG. 4 is a graph showing a relationship between a standardized levitation force (arbitrary unit) and a skew angle (deg) in which the size of a notch provided in a side rail is shown as a parameter.

FIG. 5 is an explanatory view of the air lubrication surface of the magnetic head having the air lubrication surface of the present invention, in which the narrowest portion of the side rail is offset from the side edge.

FIG. 6 is a contour diagram obtained by simulating a pressure distribution on the air lubrication surface of the magnetic head having the air lubrication surface of the present invention.

7 is a cross section A, B, C of FIG. 6 when the offset amount is 0.
6 is a graph showing a pressure distribution at a distance in the width direction.

FIG. 8 is a graph similar to FIG. 7 when the offset amount is 0.25 mm.

FIG. 9 is a graph showing the skew angle dependence of the roll angle of the slider when the offset amount is changed from 0 to 0.25 mm.

FIG. 10 is an explanatory view of the air lubrication surface of the magnetic head having the air lubrication surface of the present invention, in which the narrowest part of the side rail is inclined with respect to the side edge.

11 shows a section D, E, E in FIG. 10 at an inclination angle of 0 °;
It is a graph which shows the pressure distribution in F with respect to the width direction distance.

FIG. 12 shows a cross section D, of FIG. 10 at an inclination angle of 2.4 °.
It is a graph which shows the pressure distribution in E and F with respect to the width direction distance.

13 shows a section D, at a tilt angle of 4.8 ° in FIG.
It is a graph which shows the pressure distribution in E and F with respect to the width direction distance.

FIG. 14 is a view of a conventional negative pressure slider viewed from its air lubrication surface.

[Explanation of symbols]

Reference Signs List 1 slider (of magnetic head having air lubrication surface) 11 air lubrication surface 12, 31 side rail 121 widest part 122 inclined part or stepped part 123 narrowest part 124 offset amount 125 notch 13 pad 14 magnetism Head 15 Negative pressure area 17 Air flow 2 Magnetic recording medium 30 Slider 32 Cross rail 33 Cavity

Claims (3)

[Claims] An air lubrication surface having two side rails whose widths change along both side edges of a surface facing a magnetic recording medium and an inclined portion or a step portion provided on an inflow end side of each side rail. A magnetic head having an air-lubricated surface, wherein the side rails are widest at the inflow end and receded inside the slider at the narrowest part. 2. The air-lubricated surface according to claim 1, wherein the narrowest portion of the side rail is substantially parallel and is inclined with respect to the longitudinal direction of the slider. Magnetic head with. 3. The side rail is 6 μm from the air lubrication surface.
3. A magnetic head having an air-lubricated surface according to claim 1, wherein the magnetic head has a protrusion of not more than m.