JPH1083643A - Floating magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively suppress the occurrence of rolling of a floating magnetic head in which a head element is formed on a head slider having an air bearing surface. SOLUTION: On an air bearing surface S, an outer side rail 8 to be positioned on the outer circumferential side of a disk, an inner side rail 81 to be positioned on the inner circumferential side of the disk, and a cross rail 5 with which both side rails 8 and 81 are connected to each other at the end part of an air inflow end side are formed. Both side rails 8 and 81 have upstream rail parts 6 and 61 which are gradually narrowed in width from the upstream side to the downstream side and downstream rail parts 7 and 71 which are gradually widened in width from the upstream side to the downstream side. An inclined angle θo of a side wall 62 of the outer side rail 8, facing a middle recess 9 is formed larger than an inclined angle θi of a side wall 63 of the inner side rail 81, facing the middle recess 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flying magnetic head mounted on a hard disk drive or the like.

[0002]

2. Description of the Related Art Generally, in a hard disk drive, a disk (11) rotating at a high speed as shown in FIG.
The signal is recorded and reproduced while the magnetic head (12) attached to the tip of the swing arm (13) keeps a floating state with respect to the signal recording surface. Such a floating magnetic head (1
As 2), a negative pressure type magnetic head as shown in FIG. 17 has been proposed (Japanese Patent Publication No. 56-52380 [G11B17 / 32]). In the magnetic head, a head slider (14) on which a head element (2) and a plurality of pads (3) are formed is provided with an air bearing surface for generating a levitation force of an appropriate magnitude on a surface facing the disk. S is formed.

That is, a slope (15) is formed on the air bearing surface S on the side of the air inflow end, and a pair of side rails (17) (17) extending parallel to each other along the direction of air flow.
And a cross rail (16) for connecting the side rails (17) and (17) to each other at an end on the air inflow side. As a result, the central recess (1) is provided between both side rails (17) and (17).
8) will be formed. Therefore, the disk surface and the slope
The air flowing into the space (15) passes through the cross rail (16), and then flows along the side rails (17) and (17) and the central concave portion (18). As a result, the side rails (17) and (17) become positive pressure areas, and the central concave portion (18) becomes a negative pressure area. As a result,
The magnetic head has an elastic pressing force by the swing arm (13), a positive pressure acting on the side rails (17) (17) of the head slider (14), and a central recess (9) of the head slider (14). The floating position is kept balanced with the acting negative pressure (see FIG. 18).

[0004]

By the way, in the hard disk drive, as shown in FIG. 25, the magnetic head (12) is moved from the moving end Pi on the inner circumference side of the disk to the outer circumference of the disk by the swing of the arm (13). When the magnetic head 12 reciprocates between the moving ends Po, the angle formed by the attitude of the magnetic head 12 with respect to the disk circumferential direction, that is, the skew angle θ changes.
Also, since the disk (11) rotates at a constant angular velocity, the relative speed of the magnetic head (12) with respect to the disk (11) varies from the moving end Pi on the inner peripheral side of the disk to the moving end on the outer peripheral side of the disk. It will increase as we move to Po.

FIG. 21A shows a skew angle Skew (de)
g) as a parameter, the relative speed Spe of the magnetic head
This shows the relationship between ed (m / s) and the flying height FH (nm). Here, the skew angle Skew is set to zero when the attitude of the magnetic head (12) coincides with the disk circumferential direction in FIG. 25, and is positive and counterclockwise when the swing arm (13) is rotated clockwise. The case of turning is regarded as negative. or,
The flying height FH is determined by the head slider (14) as shown in FIG.
Of the disk (11) from the surface. As is clear from FIG. 21A, the flying height FH increases as the relative speed Speed increases. FIG. 21B illustrates the relationship between the skew angle Skew and the flying height FH using the relative speed Speed of the magnetic head with respect to the disk as a parameter. When the skew angle fluctuates around zero, the flying height is reduced. It has changed significantly.

FIG. 22A shows the relationship between the relative speed Speed of the magnetic head and the rolling amount ROLL (nm) using the skew angle Skew as a parameter. Here, the rolling amount ROLL represents a difference between the flying heights at both ends of the head slider (14) as shown in FIG. As is clear from FIG. 22A, the rolling amount changes greatly as the relative speed increases. FIG.
(b) shows the relative speed Speed of the magnetic head with respect to the disk.
Is a parameter representing the relationship between the skew angle Skew and the rolling amount ROLL. When the skew angle fluctuates around zero, the rolling amount changes greatly.

As described above, in the conventional flying magnetic head, the flying height and the rolling amount change greatly with the fluctuation of the skew angle and the relative speed of the magnetic head. In the drive device, there arises a problem that the recording / reproducing sensitivity of a signal is significantly changed.

Therefore, as a floating type magnetic head capable of suppressing a change in a flying height caused by a change in a skew angle and a relative speed, as shown in FIG. 20, both side rails (19) and (19)
Floating magnetic head formed from an upstream rail section (12) whose width decreases from the upstream side to the downstream side and a downstream rail section (13) whose width increases from the upstream side to the downstream side, respectively. Has been proposed.

FIG. 23A shows the relationship between the relative speed Speed and the flying height FH of the flying magnetic head shown in FIG. 20 using the skew angle Skew as a parameter. The increase in the flying height is smaller than in the flying magnetic head shown in FIG. FIG. 23B shows the skew angle Ske using the relative speed Speed of the magnetic head with respect to the disk as a parameter.
This shows the relationship between w and the flying height FH, and the change in the flying height due to the change in the skew angle is smaller than that in the flying magnetic head shown in FIG.

FIG. 24A shows a skew angle Skew.
Is the relative speed of the magnetic head Speed
And the rolling amount ROLL. The change in the amount of rolling with an increase in the relative speed is smaller than that in the flying magnetic head shown in FIG. 17, but the skew angle causes a large variation in the amount of rolling. FIG. 24B shows the skew angle Skew using the relative speed Speed of the magnetic head with respect to the disk as a parameter.
And the rolling amount ROLL.
The change in the rolling amount due to the change in the skew angle is shown in FIG.
However, when the skew angle is negative, the rolling amount is large.

As described above, according to the flying magnetic head shown in FIG. 20, the change in the flying height due to the fluctuation of the skew angle and the relative speed can be suppressed, but the rolling of the magnetic head is sufficiently suppressed. I can't do it.

An object of the present invention is to provide a flying magnetic head capable of effectively suppressing the occurrence of rolling.

[0013]

As shown in FIG. 25, when recording and reproducing signals while the magnetic head (12) is in a floating state, the end of the magnetic head (12) on the inner peripheral side of the disk and the outer peripheral side of the disk are separated. At the end, a speed difference occurs according to the width of the magnetic head (12). For example, as is clear from FIG. 23A, even if the skew angle is the same, as the relative speed increases, the levitation force increases and the levitation amount FH increases. At the peripheral end and the outer peripheral end of the disk, there is a difference in the floating force according to the speed difference, and rolling is caused by the deviation of the floating force. Therefore, in the present invention, the negative pressure region formed on the air bearing surface is deviated from the disk inner peripheral side to the disk outer peripheral side, and the deviation of the floating force is offset by the deviation of the negative pressure, The rolling amount is made as close to zero as possible.

In the flying magnetic head according to the present invention, the outer side rail (8) to be located on the outer peripheral side of the disk (11) and the inner peripheral side of the disk (11) are located on the air bearing surface S. An inner side rail (81) to be formed is formed so as to extend in the direction of air flow, and a cross rail (5) connecting both side rails (8) and (81) to each other at an end on the air inflow side. ) Is formed. Each of the side rails (8) and (81) has an upstream rail portion (6) (61) whose width decreases from the upstream side to the downstream side and a downstream rail portion whose width increases from the upstream side to the downstream side. (7) The outer side rail (8) and the inner side rail so that the negative pressure generated by the outer side rail (8) is larger than the negative pressure generated by the inner side rail (81).
(81) are formed non-linearly symmetric with each other.

In the above-mentioned floating magnetic head, both side rails (8) and (81) have an upstream rail section (6) and (61) whose width decreases from the upstream side to the downstream side, respectively, and a downstream side from the upstream side. With the configuration including the downstream rails (7) and (71) whose width increases toward the side, a change in the flying height due to a change in the skew angle and the relative speed is suppressed.

In the above-mentioned floating magnetic head, the outer side rail (8) and the inner side rail (81) are formed to be non-symmetrical with each other.
The negative pressure generated by (8) is the inner side rail (81)
The pressure is greater than the negative pressure generated. Since the negative pressure exerts an acting force to attract the magnetic head toward the disk, the deviation of the negative pressure in the disk radial direction and the deviation of the levitation force in the disk radial direction cancel each other, thereby suppressing the magnetic head from rolling. Is done.

In a specific configuration, the upstream rail portion (6) of the outer side rail (8) is provided with an inner side rail (8).
The width is reduced at a larger rate of change than the upstream rail portion (61) of (1). More specifically, a central recess (9) is formed between the outer side rail (8) and the inner side rail (81), and the upstream rail portions (6) (61) of both side rails (8) (81) are formed. )
Respectively, the side walls (62) and (63) facing the central recess (9) make constant inclination angles θo and θi with respect to the rail longitudinal direction, and the inclination angle of the side wall (62) of the outer side rail (8). θo is formed to be larger than the inclination angle θi of the side wall (63) of the inner side rail (81).

In the above specific configuration, the inclination angle θo of the side wall (62) of the outer side rail (8) is larger than the inclination angle θi of the side wall (63) of the inner side rail (81). (8) The negative pressure region formed between (81) is biased toward the outer side rail (8), and the outer side rail is closer than the inner side rail (81).
A large negative pressure is generated on the (8) side. The bias of the negative pressure and the bias of the levitation force cancel each other, and the rolling of the magnetic head is suppressed.

[0019]

According to the flying magnetic head of the present invention, the distribution of the negative pressure acting on the head slider in the radial direction of the disk and the distribution of the floating force are balanced with each other, so that the occurrence of rolling can be effectively prevented. Can be suppressed.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. The flying magnetic head according to the present invention has a head slider shown in FIGS.
It has (1). The head slider (1) has, on the air bearing surface S, an outer side rail (8) located on the outer peripheral side of the disk, an inner side rail (81) located on the inner peripheral side of the recording medium, and both side rails. Rail (8) (81)
Rails that connect to each other at the air inlet end
(5), whereby both side rails (8) (81)
A central concave portion (9) serving as a negative pressure region is formed therebetween.
The cross rail (5) has a slope (4) for introducing air at the end on the air inflow side.

Each of the side rails (8) and (81) has an upstream rail portion (6) and (61) whose width decreases from the upstream side to the downstream side at a constant rate of change, and a side from the upstream side to the downstream side. And a downstream rail portion (7) (71) whose width increases at a constant rate of change. Here, the upstream rail section of both side rails (8) and (81)
(6) and (61) are side walls of the outer side rail (8), respectively, in which the side walls (62) and (63) facing the central concave portion (9) make constant inclination angles θo and θi with respect to the longitudinal direction of the rail. (62) inclination angle θ
o is the inclination angle θ of the side wall (63) of the inner side rail (81)
It is formed larger than i. Also, head slider
Outer side rail (8) from the end face on the air inflow side of (1)
The distance Lo to the downstream end of the upstream rail portion (6) is
The distance Li from the end face on the air inflow side of the head slider (1) to the downstream end of the upstream rail portion (61) of the inner side rail (81) is formed smaller.

FIGS. 3 (a) and 3 (b) show a head slider model of a computer simulation performed to confirm the effect of the flying magnetic head of the present invention. The length A along the air flow direction of the head slider (1) is 2.
032 mm, the width B in the disk radial direction is 1.6 mm, and the radial distance R from the rotation of the disk to the center of the head slider (1) is 22.86 mm. Disk rotation speed is 5
400 rpm. The pressing force of the magnetic head against the disk signal surface is 3.5 g. In the computer simulation, the minimum width c at the connection between the upstream rails (6) and (61) and the downstream rails (7) and (71) of both side rails (8) and (81) is 0.231 mm, as shown in FIG. Rail (6)
While the maximum width d of (7) is kept at 0.431 mm, the upstream side of the outer side rail (8) as shown in FIG.
The position of the connecting portion between (6) and the downstream rail portion (7) is a = 0.6.
4 shifted from the 32 mm position by an interval of b = 0.3 mm
And four models having inner side rails (81) that are symmetrical with the outer side rails (8) of the four models as shown in FIG.
, The rolling amount ROL under the conditions described later.
L was calculated. However, the models were common because the outer side rail (8) and the inner side rail (81) are line-symmetric with each other. The computer simulation is a well-known method based on the Reynolds equation.
(For example, Transactions of the Opportunity Society of Japan (C edition) 53, 487 (Showa 62
-3) "Analysis of thin film gas lubrication characteristics based on Boltzmann equation").

The graphs of FIGS. 4 to 16 show the results of the computer simulation. FIGS. 4A and 4B show the model, FIGS. 5A and 5B show the model, and FIG. (b)
8 shows the model, FIGS. 7A and 7B show the model, FIG.
9 (a) and 9 (b) show the above model, FIGS. 9 (a) and 9 (b) show the above model, FIGS. 10 (a) and 10 (b) show the above model, and FIGS. 11 (a) and 11 (b) show the rolling characteristics of the above model. ing. FIG.
As is clear from the comparison of the graphs of FIGS. 7A and 7B to FIGS. 7A and 7B, the rolling amount ROL in the order of model >>>>
L decreases, and in the model shown in FIGS. 5 (a) and 5 (b),
The rolling amount ROLL is substantially zero regardless of the change in the relative speed Speed and the change in the skew angle Skew.

As is clear from the comparison of the graphs of FIGS. 8 (a) (b) to 11 (a) (b), the rolling amount ROLL decreases in the order of model >>>>, and FIG. (a)
In the model shown in (b), the rolling amount ROLL is a value close to zero irrespective of the change in the relative speed Speed and the change in the skew angle Skew.

From the above results, as shown in FIGS. 1 and 2, the inclination angle θo of the side wall (62) of the outer side rail (8) is larger than the inclination angle θi of the side wall (63) of the inner side rail (81). It can be seen that by setting, rolling can be suppressed. However, as can be determined from the calculation results of the model, setting the inclination angle θo to an excessive value of 45 degrees or more rather causes an increase in rolling.

As described above, the relationship of θo> θi is effective for suppressing rolling because of the following reason.
(8) The negative pressure region formed between (81) is biased toward the outer side rail (8), and a larger negative pressure is generated on the outer side rail (8) side than on the inner side rail (81) side. This is because the bias of the negative pressure and the bias of the levitation force distributed in the disk radial direction cancel each other.

FIG. 12 shows the width and length on the air bearing surface when the skew angle is zero in the model.
13 shows the distribution of pressure in the (Length) direction in a three-dimensional manner. FIG. 13 is a graph of the graph of FIG. 12 viewed from the direction of arrow F, and FIG. 14 is a graph of the graph of FIG. FIG. 15 is a graph when the graph of FIG. 12 is viewed from the arrow Q direction. In these graphs, the width (Wid
th) and length are 2.032 m of the length of the magnetic head.
The point of Width = 0 is the end point on the inner circumference side of the disk, and the point of Width = 0.8 is the end point on the outer circumference side of the disk. The pressure is also dimensionless, and the pressure = 0 point is the atmospheric pressure. On the other hand, FIG.
Is a graph corresponding to FIG. 13 in the model.

As is clear from the graphs of FIGS. 12 and 13, positive pressure (lifting force) is applied to both side rails of the air bearing surface.
Pi and Po are generated, and negative pressures Mi and M
is generated, and the negative pressure Mi of the inner side rail and the outer side rail Mo are distributed at substantially the same value, whereas the positive pressure Po of the outer side rail is higher than the positive pressure Pi of the inner side rail. Distributed by value.
The difference in the positive pressure is due to the difference in the relative speed between the two side rails, and the difference in the positive pressure, that is, the bias in the levitation force causes the rolling shown in FIG. 6.

On the other hand, in the graph of FIG. 16, similarly, the positive pressure P
o 'indicates a value larger than the positive pressure Pi' of the inner side rail. Also, M inside the outer side rail
o 'is distributed with a value larger than the negative pressure Mi inside the inner side rail. This bias of the negative pressure is due to the fact that the inclination angle θo of the side wall (62) of the outer side rail (8) is larger than the inclination angle θi of the side wall (63) of the inner side rail (81) as described above. is there. As a result, on the outer side rail side, the increase in the positive pressure and the increase in the negative pressure cancel each other, and the forces acting on the head slider are balanced on both sides, so that rolling is suppressed.

The description of the above embodiments is for the purpose of explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof.
In addition, the configuration of each part of the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made within the technical scope described in the claims.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a head slider of a flying magnetic head according to the present invention.

FIG. 2 is a plan view of the head slider.

FIG. 3 is a plan view illustrating a head slider model used for computer simulation.

FIG. 4 is a graph showing rolling characteristics in a model.

FIG. 5 is a graph showing rolling characteristics in a model.

FIG. 6 is a graph showing rolling characteristics in a model.

FIG. 7 is a graph showing rolling characteristics in a model.

FIG. 8 is a graph showing rolling characteristics in a model.

FIG. 9 is a graph showing rolling characteristics in a model.

FIG. 10 is a graph showing rolling characteristics in a model.

FIG. 11 is a graph showing rolling characteristics in a model.

FIG. 12 is a graph showing a pressure distribution in a model.

FIG. 13 is a graph of the graph of FIG.

FIG. 14 is a graph of the graph of FIG. 12 viewed from the arrow T side.

FIG. 15 is a graph of the graph of FIG. 12 viewed from the arrow Q side.

FIG. 16 is a graph corresponding to FIG. 13 in the model.

FIG. 17 is a perspective view of a conventional head slider.

FIG. 18 is a diagram illustrating a flying height of a head slider.

FIG. 19 is a diagram illustrating a rolling amount of a head slider.

FIG. 20 is a plan view of another conventional head slider.

21 is a graph showing flying characteristics of the head slider shown in FIG.

FIG. 22 is a graph showing rolling characteristics of the head slider.

FIG. 23 is a graph showing flying characteristics of the head slider shown in FIG. 20;

FIG. 24 is a graph showing rolling characteristics of the head slider.

FIG. 25 is a plan view illustrating a main part of the hard disk drive.

[Explanation of symbols]

 (1) Head slider (4) Slope (5) Cross rail (8) Outer side rail (81) Inner side rail (6) Upstream rail (61) Upstream rail (7) Downstream rail (71) Downstream rail (62) Side wall (63) Side wall (9) Central recess

Claims (3)

[Claims] 1. A head slider (1) having an air bearing surface S to face a disk-shaped recording medium is provided with a head element.
In the flying type magnetic head formed with (2), the air bearing surface S has an outer side rail (8) located on the outer peripheral side of the recording medium and an inner side rail (8) located on the inner peripheral side of the recording medium. Rails (81) are formed so as to extend in the air flow direction, and both side rails (8) (8)
1) Cross rail that connects to each other at the air inflow side end
(5) is formed, and both side rails (8) and (81) are upstream rail portions (6) and (6) whose width decreases from the upstream side to the downstream side, respectively.
1) and a downstream rail (7) (71) whose width increases from the upstream side to the downstream side, and the negative pressure generated by the outer side rail (8) is generated by the inner side rail (81). The floating magnetic head is characterized in that the outer side rail (8) and the inner side rail (81) are formed non-linearly symmetric with each other so as to be larger than the negative pressure. The upstream rail (6) of the outer side rail (8) is connected to the upstream rail (6) of the inner side rail (81).
2. The flying magnetic head according to claim 1, wherein the width is reduced at a rate of change larger than 1). 3. A central recess (9) is formed between the outer side rail (8) and the inner side rail (81), and the upstream rails (6) (61) of both side rails (8) (81). Respectively, the side walls (62) and (63) facing the central recess (9) make constant inclination angles θo and θi with respect to the rail longitudinal direction, and the inclination angle of the side wall (62) of the outer side rail (8). 3. The flying magnetic head according to claim 2, wherein θo is formed to be larger than the inclination angle θi of the side wall of the inner side rail.