JP2518826B2 - Floating magnetic head - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magnetic head used in a magnetic recording device, and more particularly to a magnetic head in which the gap between the magnetic flux gap portion of the magnetic head and the magnetic recording medium can be easily reduced and The present invention relates to a floating magnetic head which has a flying slider surface capable of stably flying the head, is easily manufactured on the flying slider surface, and is suitable for high density magnetic recording.

[Conventional technology]

A magnetic head used in a magnetic drum or a magnetic disk recording device used as an external recording device of a conventional electronic computer is disclosed in, for example, JP-A-60-101781, JP-A-60-136004, and JP-A-60-136004. There is a proposal in Japanese Patent Laid-Open No. Sho 60-131684. These are of a type in which the flying slider surface of the magnetic head and the magnetic flux gap are located on the same plane, although there are some differences in their respective structures. In the magnetic head of this structure, in order to reduce the distance between the magnetic flux gap portion and the magnetic recording medium to improve the magnetic recording density, there is a difficult technical problem that the flying height of the entire magnetic head must be reduced. Occurs. That is, as shown in FIG. 7, there is a pair of slide rails 11 forming the flying slider surface 2 on one side of the magnetic head 1. The slide rail 11 is provided with an air inflow taper portion 6 for introducing an air flow 10 in the direction of the arrow and producing a dynamic pressure effect. Slide rail 11
The surface formed by a pair of flat surfaces between the air inflow end 4 and the air outflow end 5 is referred to as a flying slider surface 2. On the air outflow end 5 side in the center of the magnetic head 1, there is a magnetic core portion 12 around which a coil 13 through which a signal current for recording / reproducing flows is wound, and a magnetic flux gap portion 3 is provided through a glass 14 for a magnetic flux gap. is there. FIG. 8A shows the floating state of the conventional magnetic head 1 shown in FIG. 7 with respect to the magnetic recording medium.
An arrow A view of the magnetic head 1 shown in FIG. 8A is shown in FIG. 8B, and an arrow B view thereof is shown in FIG. 8C. The magnetic disk 8, which is a magnetic recording medium, rotates at high speed in the direction of arrow 9. The magnetic head 1 is attached to a magnetic head moving mechanism (not shown) by a support spring and an arm. Assuming that the distance between the air inflow end 4 of the flying slider surface 2 formed by the pair of slide rails 11 of the magnetic head 1 and the magnetic disk 78 is h ₁ , and the distance between the air outflow end 5 and the magnetic disk 8 is h, The magnetic head 1 floats so that h ₁ ≧ h. Therefore, the minimum distance between the magnetic head 1 and the magnetic disk 8 is h. On the other hand, since the magnetic flux gap portion 3 is provided near the air outflow end 5 on the same plane as the flying slider surface 2, the distance between the magnetic flux gap portion 3 and the magnetic disk 8 is approximately h. Here, in order to improve the magnetic recording density by reducing the distance h between the magnetic flux gap portion 3 and the magnetic disk 8, the flying height of the entire magnetic head 1 having a wide flying slider surface 2 in the same plane is extremely reduced. Since it is necessary to keep it low, the amount of air flowing into the flying slider surface 2 is small, and the air layer is very thin, this is a technically extremely difficult problem. Further, in this type of conventional magnetic head, the floating of the magnetic head is likely to be unstable due to the meshing of dust in the air passing through the gap between the magnetic head and the magnetic recording medium, and therefore the floating of the magnetic head. The end of the slider surface frequently contacts the magnetic recording medium, causing a so-called head crash phenomenon, which causes the magnetic recording medium to be demagnetized or damaged, and has the drawback that the performance and reliability of high-density magnetic recording deteriorate. .

On the other hand, in Japanese Unexamined Patent Publication No. 51-144218, which is the same applicant as the present invention, a core portion having a magnetic flux gap portion is projected from the flying slider surface of a floating magnetic head, and the frequency of head crashes is relatively low. , A high-performance and highly-reliable levitation type magnetic head capable of reducing the gap between the magnetic flux gap and the magnetic recording medium has been proposed.
It is extremely difficult to machine a set of flying slider surfaces with the magnetic flux gap portion protruding in the center sandwiched between them without damaging the magnetic flux gap portion with high surface accuracy.
It was not possible to make a large number of heads suitable for the purpose, and it was not possible to fully satisfy the high-density magnetic recording with high reliability.

[Problems to be solved by the invention]

As described above, in the conventional floating magnetic head in which the magnetic flux gap portion and the slider air bearing surface are in the same plane, when the distance between the magnetic flux gap portion and the magnetic recording medium is reduced, it is attempted to increase the recording density. However, a difficult technical problem arises in that the flying height of the entire magnetic head must be reduced. That is, the flying height of a magnetic head used in a magnetic disk device or the like needs to be kept below 0.3 μm from 0.1 μm in the future in order to improve electromagnetic conversion characteristics and achieve high density recording. (Nikkei Electronics, 1985/9/23, p183-p19)
9) In principle, the mean free path of gas molecules (0.06 μm at 1 atm for air) is possible. But,
Reducing the flying height of the entire magnetic head is extremely difficult in practice because the thickness of the air layer flowing into the flying slider surface is very small, and it is necessary to make great efforts technically. The problem of not becoming a problem arises. In the floating magnetic head in which the magnetic flux gap portion and the flying slider surface are in the same plane, the flying stability of the magnetic head is extremely poor. Therefore, the end of the flying slider surface of the magnetic head becomes a magnetic recording medium. There is a drawback in that the magnetic recording medium is significantly damaged due to frequent contact with the head and the performance and reliability of the high density magnetic recording are deteriorated.

On the other hand, in the conventional floating magnetic head in which the core portion having the magnetic flux gap portion is projected from the flying slider surface forming the same plane to reduce the distance from the magnetic recording medium to achieve high density recording, high precision is achieved. It was extremely difficult to machine a structure in which only the magnetic flux gap portion was projected in the center while keeping a pair of flying slider surfaces on the same plane, which required high surface accuracy.

An object of the present invention is to solve the above-mentioned drawbacks or problems of the conventional technology, to reduce the gap between the magnetic flux gap portion and the magnetic recording medium while keeping the flying height of the magnetic head at a high flying height, and Provides a floating magnetic head that has a flying slider surface that allows the head to fly stably, has extremely low probability of head crash, has excellent electromagnetic conversion characteristics, is suitable for high-density magnetic recording, and is easy to manufacture To do.

[Means for solving problems]

The present invention provides a floating magnetic head having a magnetic flux gap portion for performing magnetic recording and reproduction by electromagnetic conversion and having a flying slider surface which is levitated by an air flow generated by movement or rotation of a magnetic recording medium. Two or more flat surfaces are formed so that a protrusion protruding gently toward the magnetic recording medium side is formed in a substantially vertical plane including the center line extending in the direction of the air flow centering on the magnetic flux gap. Portion or one or more curved surface portions constitute a flying slider surface, and a magnetic flux gap portion is formed at a position where the distance between the protruding portion of the flying slider surface and the magnetic recording medium is almost minimized when the magnetic head is flying. By providing, the object of the present invention can be achieved.

The floating magnetic head of the present invention is parallel to the magnetic disk, and in the direction perpendicular to the magnetic disk surface due to the dynamic pressure effect of the air flow in the x-axis direction of the xy plane consisting of the x-axis and the y-axis which are orthogonal to each other. A floating magnetic head having a flying slider surface that floats in a certain z-axis direction, wherein the flying slider surface is formed in a direction perpendicular to the center line of the flying slider surface in the x-axis direction. , The flying slider surface,
The intersecting line where the z-axis and the zy plane consisting of the y-axis intersect is composed of two straight lines intersecting with the center line as the intersecting point, and at least a magnetic flux gap is provided at the intersecting point.
Further, according to the present invention, in the floating magnetic head according to claim 1, the line of intersection between the flying slider surface and the zy plane is a curve having a curvature, and the line is the closest to the magnetic disk surface. The structure has at least a magnetic flux gap.

[Action]

In the floating magnetic head of the present invention, the magnetic flux gap is provided on the protrusion of the flying slider surface formed by a plurality of flat surfaces or curved surfaces, and the magnetic flux gap is provided at the position closest to the magnetic recording medium side. Since the slider surface is kept at a relatively large distance from the magnetic recording medium, a large amount of inflowing air can obtain a stable levitation force of an appropriate size for the magnetic head. Since the distance between the magnetic flux gap and the magnetic recording medium can be controlled to be extremely small, the electromagnetic conversion characteristics are significantly improved and stable high density magnetic recording can be achieved.

Further, the floating slider surface of the floating magnetic head of the present invention has a large distance from the magnetic recording medium, so that it has a structure that aerodynamically stable and large flying force can be obtained. A magnetic head in which the flying slider surface and the magnetic flux gap are on the same plane is modified to extend the core having the magnetic flux gap to the downstream side, or a magnetic head in which only the magnetic flux gap is sharply projected. In comparison, the flying characteristics of the magnetic head are remarkably stable, stress is not concentrated due to contact with the magnetic recording medium, and damage to the magnetic flux gap of the head and head crush can be significantly reduced. Since the magnetic flux gap is on the line of intersection of the planes, the flying slider surface of the magnetic head composed of a plurality of planes or curved surfaces can be processed by simple polishing. It's easy.

Further, the magnetic head having the flying slider surface of the present invention makes it easy to control the attitude when landing on the magnetic recording medium, and stress is not concentrated on the contact surface with the magnetic head, so that the magnetic recording medium High-density magnetic recording can be achieved with high reliability without damaging or damaging the magnetic head itself.

〔Example〕

Hereinafter, an embodiment of the present invention will be described in more detail with reference to the drawings. In the drawings, the parts denoted by the same reference numerals are the same parts or parts having the same function or the same performance.

(Embodiment 1) FIGS. 1A, 1B and 1C are schematic views showing the structure of a floating magnetic head which is an example of the present invention. As shown in FIG. 1 (a), the magnetic head 1 is magnetized by the dynamic pressure effect of the air flow in the x-axis direction parallel to the magnetic disk 8 which is a magnetic recording medium rotating at high speed in the direction of arrow 9. It is levitated in the z-axis direction which is the vertical direction of the disk 8. Positioning in the xy plane parallel to the magnetic disk 8 is performed by a support spring of the magnetic head and an arm portion (neither is shown). The flying slider surface 2 of the magnetic head 1 is shown in FIG. 1 (b) [view from the arrow A in FIG. 1 (a)] and FIG. 1 (c).
As shown in the [B arrow view of FIG. 1 (a)], zy
It is achieved by two planes whose intersections with the planes are ▲ ▼ and ▲ ▼. In the case of this embodiment, the slider width w of the magnetic head 1 is 3.2 mm,
Of the air outflow end 5 and the magnetic flux gap 3 in the normal direction h ₀
= 0.2 μm, the intersection angle θ of the above two planes is
The flying slider surface 2 of the magnetic head 1 is formed by two planes intersecting each other at 2h ₀ /w=1.25×10 ⁻⁴ rad = 25.78 seconds, and the air inflow end 4 is formed in front of it. The magnetic flux gap 3 of the magnetic head 1 is provided on the line of intersection of the two flying slider surfaces 2 including the point P ₂ . When the distance between the air outflow end 5 of the magnetic head 1 and the magnetic disk 8 in the normal direction is h, the distance in the normal direction between the magnetic flux gap portion 3 and the magnetic disk 8 is Δh = (h−h ₀ ). . In the case of this embodiment, the distance h ₁ between the air inflow end 4 and the magnetic disk 8 is 0.8 μm, the distance h between the air outflow end 5 and the magnetic disk 8 is h = 0.4 μm, and the air outflow end 5 and the magnetic disk 8 are Distance in the direction of the normal to the front end of the facing magnetic flux gap 3 h ₀ = 0.2μ
Since m is m, it is possible to achieve the distance Δh = 0.2 μm between the magnetic flux gap portion 3 and the magnetic disk 8.

(Embodiment 2) In this embodiment, FIG. 2 (a), (b), (c)
As shown in FIG. 1, an example of the floating magnetic head of the present invention when it is provided at the magnetic flux gap portion 3 of the thin film magnetic head 1 and the air outflow end 5 of the flying slider surface 2 is shown.

2 (a) is a perspective view showing the structure of the thin-film magnetic head 1, and FIG. 2 (b) is a structure of the air outflow end 5 portion having the magnetic flux gap portion 3 in FIG. 2 (a). 2C is a schematic diagram showing a floating state of the magnetic head shown in FIG. 2A. In the thin film type magnetic head 1 of this embodiment, as shown in FIG. 2B, the flying slider surface 2 is a cylindrical surface having a radius of curvature R, and the magnetic flux gap portion 3 is located at the top portion thereof. The air inflow end 4 of the flying slider surface 2 is one plane and intersects the flying slider surface 2.

In this embodiment, the slider width is w, and the flying slider surface 2
Let R be the radius of curvature of, and the vertical distance between the air outflow end 5 and the tip of the magnetic flux gap 3 facing the magnetic disk 8.
When h ₀ , the following relational expression holds.

^{_{h 0 2 -2R · h 0 +}} w 2/4 = 0 where, w = 3mm, R = 5.625m , a h ₀ = 0.2 [mu] m, the distance h ₁ = 0.8 [mu] m between the air inlet end 4 and the magnetic disk 8 Then, when the distance h between the air outflow end 5 and the magnetic disk 8 is 0.4 μm, the distance Δh between the magnetic flux gap portion 3 and the magnetic disk 8 is (h− (h−
It is possible to obtain h ₀ ) = 0.2 μm. In the case of this embodiment, the flying slider surface 2 is one continuous cylindrical surface, but it is also possible to form an escape groove for the air flow or to make the cylindrical surface any curved surface. In any case, the feature of the present invention resides in that the magnetic flux gap portion 3 is provided at the top of the curved surface, that is, at the position where the distance from the magnetic disk is minimized when the magnetic head is flying.

(Example 3) The magnetic head (h ₀ used in Example 1 of the present invention was used.
= 0.2 μm) and a magnetic head (h ₀ = 0), which is a conventional type, with the flying slider surface and the magnetic flux gap part in the same plane, the magnetic flux gap part and magnetic field The flying height of the magnetic head [spacing Δh (μm)], which is the distance from the disk, was variously changed, and the frequency (times / s) at which the magnetic head contacted the magnetic disk was measured. FIG. 3 shows the results. In the above measurement of the contact frequency, the spacing Δh is kept constant at a predetermined value, a piezo element (shock detection sensor) for contact detection is attached to the magnetic head, and the magnetic head is sought in the radial direction of the magnetic disk. It was operated and the frequency with which the magnetic head contacted the magnetic disk was measured. As can be seen from the figure, when the paging Δh = 0.2 μm, the magnetic head shown in the first embodiment of the present invention has about 2.7 times / s.
The contact frequency is extremely low, whereas the conventional magnetic head has about 27 times / s, which is about 10 times more contact with the magnetic disk, and thus the floating magnetic head of the present invention is more excellent in levitation characteristics. I understand.

(Embodiment 4) Next, a head seek mechanism when the floating magnetic head shown in Embodiments 1 and 2 is used in a magnetic disk device will be described.

FIG. 4 shows Example 1 [FIGS. 1 (a), (b),
The magnetic head 1 shown in (c)] is grounded on the stopped magnetic disk 8 while being supported by the magnetic head support mechanism 15.

FIG. 5 shows Example 2 [FIGS. 2 (a), (b),
The thin-film magnetic head 1 shown in (c)] has a magnetic head supporting mechanism 15 on the magnetic disk 8 which is stopped.
Shows the state of being grounded while being supported by. Fourth
In both FIGS. 5 and 5, the magnetic head 1 is landed in a state in which one side of the flying slider surface 2 is low and the other side is high, because a predetermined amount of moment M is applied by the support mechanism 15 in advance. . By doing so, it is possible to prevent an excessive contact stress from acting only on the magnetic flux gap portion 3 protruding in a small area. Further, as shown in FIG. 6A, it is possible to support the magnetic flux gap portion 3 with respect to the magnetic disk 8 in a non-contact state.

As described above, the moment M is constantly applied to the magnetic head 1 by the support mechanism 15. However, when the magnetic disk 8 reaches a predetermined rotation speed, as shown in FIG. Due to the difference in peripheral speed between the outer peripheral side and the inner peripheral side, a buoyancy difference of F ₀ > F _i is generated between the outer peripheral side buoyancy F ₀ and the inner peripheral side buoyancy F _{i in} the magnetic head 1, and the support mechanism is The moment M due to 15 is canceled out. As a result, the sixth
As shown in FIG. 6A, the distance Δh between the magnetic flux gap portion 3 and the magnetic disk 8 is stably maintained. In order to generate a buoyancy difference such as F ₀ > F _i , it is possible to perform an aerodynamic design such as changing the width of a pair of flying slider surfaces 2 of the magnetic head 1 shown in FIG. In addition, the attitude of the magnetic head 1 at the time of landing can be controlled arbitrarily, and the dirt on the flying slider surface 2 can be removed and the symmetry of the shape can be maintained by rolling in the x-axis direction at the time of landing. Is also possible.

As described in the above embodiments, in the floating magnetic head according to the present invention, only the magnetic flux gap portion is brought close to the magnetic disk which is the magnetic recording medium, and the distance between the flying slider surface and the magnetic disk can be made relatively large. Since it is possible, the air layer passing over the slider air bearing surface becomes thicker, and aerodynamically stable flying characteristics can be obtained. Therefore, it is possible to obtain a magnetic head with extremely low frequency of head crash due to contact with the magnetic disk. High-density magnetic recording is possible. Further, since the processing method is easy, a large number of highly reliable heads can be provided at low cost.

〔The invention's effect〕

As described above in detail, in the floating magnetic head of the present invention, the distance between the magnetic flux gap and the magnetic recording medium is extremely small while keeping the flying slider surface equal to or higher than the conventional magnetic head. Since it can be controlled, the electromagnetic conversion characteristics are improved, a stable floating state is achieved, and the head crash phenomenon due to contact with the magnetic recording medium can be significantly reduced, and high-density magnetic recording with high reliability can be achieved. Is possible. Further, since the floating slider surface of the floating magnetic head of the present invention has a structure in which a magnetic flux gap portion is provided at the top formed by two or more flat portions or one or more curved portions, it is projected. The contact stress is not concentrated on the magnetic flux gap portion, the attitude when landing on the magnetic recording medium is extremely easy to control, and the manufacturing process is simple, and a high-performance magnetic head can be obtained.

[Brief description of drawings]

1A is a schematic diagram showing a floating state of the magnetic head shown in Embodiment 1 of the present invention, and FIG. 1B is a view of the magnetic head shown in FIG. 1C is a perspective view of the magnetic head shown in FIG. 1A, and FIG. 2A is a perspective view showing the structure of the magnetic head according to the second embodiment. FIG. FIG. 2A is an enlarged view of a main part of the magnetic head of FIG.
FIG. 3C is a schematic diagram showing the floating state of the magnetic head of FIG. 2A, and FIG. 3 is the spacing and contact with the magnetic disk when the magnetic head of Example 1 and the conventional magnetic head are used. 4 is a schematic diagram showing the grounding state of the magnetic head shown in FIG. 1, FIG. 5 is a schematic diagram showing the grounding state of the magnetic head shown in FIG. 2, and FIG. FIG. 6 (a) is a schematic view showing the non-contact support state of the magnetic head shown in FIG. 2, and FIG. 6 (b) is a peripheral speed difference of the magnetic disk with respect to the magnetic head of FIG. 6 (a). Fig. 7 is a perspective view showing an example of the structure of a conventional magnetic head, Fig. 8 (a) is a schematic diagram showing the floating state of the magnetic head shown in Fig. 7, FIG. 8 (b) is the eighth
FIG. 8A is a view of the magnetic head of FIG.
It is a B arrow line view of the magnetic head of FIG. 1 ... Magnetic head, 2 ... Flying slider surface 3 ... Magnetic flux gap part, 4 ... Air inflow end 5 ... Air outflow end, 6 ... Air inflow taper part 8 ... Magnetic disk, 9 ... Rotation direction 10 …… Air flow, 11 …… Slide rail 12 …… Magnetic core, 13 …… Coil 14 …… Flux gap glass 15 …… Support mechanism

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kuninori Imai 1-280 Higashi Koigakubo, Kokubunji City Central Research Institute, Hitachi Ltd. (72) Inventor Takeji Shiokawa 1-280 Higashi Koigakubo, Kokubunji City Central Research Institute, Hitachi Ltd. (56) References JP-A-57-105824 (JP, A) JP-A-56-153558 (JP, A)

Claims (2)

(57) [Claims] 1. A z-axis direction, which is a direction perpendicular to the surface of the magnetic disk, by a dynamic pressure effect of an air flow in the x-axis direction of an xy plane which is parallel to the magnetic disk and is orthogonal to the x-axis and the y-axis. A floating magnetic head having a flying slider surface that floats on the surface of the flying slider surface, the flying slider surface being formed from two flat portions gently protruding toward the magnetic disk surface with a center line of the flying slider surface in the x-axis direction as a ridgeline. That is, two intersecting lines formed by intersecting the two plane portions and the zy plane portion forming the flying slider surface intersect with each other with the center line as the intersecting point, and at least the magnetic flux gap portion is provided at the intersecting point. Characteristic floating type magnetic head. 2. An intersection line between the flying slider surface and the zy plane is a curve having a curvature, and at least a magnetic flux gap portion is provided in a portion closest to the magnetic disk surface. The floating magnetic head according to item 1.