JPH06267018A - Core for magnetic head and its manufacture - Google Patents

Abstract

PURPOSE:To obtain the core for a magnetic head in a new structure which can attain low-impedance characteristics while sufficiently maintaining core strength. CONSTITUTION:In a core 42 for a magnetic head where an annular closed magnetic circuit is formed by performing butt welding of first and second ferrite members in one piece, a reinforcing glass member 22 is provided at the butt- welded part of at least one side of the first and second ferrite members. At the same time, a track part 28 which is formed at the butt-welded part and a connection magnetic circuit 30 with a specific length reaching the track part 28 are constituted in a plate-shaped status with a specific length protruding on the glass member 22 and the reinforcing glass member 22 is exposed to the side of a slide surface 24 at both sides of the track part 28 and the connection magnetic circuit 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head core and a method of manufacturing the same, and more particularly, to a magnetic head core having a novel structure in which inductance is reduced and which can advantageously cope with high recording density of a magnetic recording medium. And its manufacturing method.

[0002]

BACKGROUND ART In recent years, there has been a great demand for higher recording density in magnetic recording media such as floppy disks, magnetic disks, and magnetic tapes.
Due to the increase in linear density in magnetic recording media, research and development of technologies for realizing miniaturization, large capacity, and high speed have been actively conducted.

By the way, conventionally, RDD, HDD, F
As a magnetic head used for a DD or the like, first and second ferrite members are integrally butt-joined to each other to form an annular closed magnetic path whose outer peripheral surface partially constitutes a sliding surface of a magnetic recording medium. At the same time, a magnetic head core having a track portion having a magnetic gap formed at their butt joints is used, and a winding coil is attached to the magnetic head core. ing.

However, in the magnetic head core having the magnetic path formed by the ferrite member as described above, it is difficult to reduce the inductance, and
There is a problem that a high frequency signal cannot be used due to the restriction due to the resonance frequency, and it is difficult to cope with the high recording density of the magnetic recording medium.

That is, in order to reduce the inductance in the magnetic head core, it is effective to reduce the cross-sectional area of the ferrite member forming the magnetic path.
The applicant of the present application filed Japanese Patent Application No. 2-81386 (Japanese Patent Application Laid-Open No. 3-28).
However, in addition to the fragility of the ferrite material, it is necessary to secure the core strength when winding or mounting the coil. Was difficult to make sufficiently small, and therefore, in the conventional technology,
The low-inductance characteristics have not yet been fully achieved.

[0006]

The present invention has been made in view of the circumstances as described above, and the problem to be solved is to achieve a low inductance characteristic while sufficiently securing the core strength. It is an object of the present invention to provide a magnetic head core having a novel structure and an advantageous manufacturing method thereof.

[0007]

In order to solve such a problem, in the present invention, first and second ferrite members are integrally butt-joined to each other, and a part of the outer peripheral surface slides on a magnetic recording medium. In a core for a magnetic head, which forms an annular closed magnetic path that forms a surface, and forms a track portion having a magnetic gap at the butt joint portion on the sliding surface side of the first and second ferrite members, A reinforcing glass member is disposed on at least one ferrite member side in the joint portion of the first and second ferrite members, and is formed on at least one side of the first ferrite member and the second ferrite member. The track portion and the connecting magnetic path of a predetermined length leading to the track portion are formed by a plate-like shape having a predetermined thickness protruding above the reinforcing glass member, and In the width direction on both sides of the rack portion and the connecting magnetic path, the magnetic head core comprising brought revealing reinforcing glass member on the sliding surface side, it is to its features.

Further, according to the present invention, (a) by butt-joining each other, a part of the outer peripheral surface forms an annular closed magnetic path forming a sliding surface of the magnetic recording medium. A step of preparing a first ferrite block and a second ferrite block in which at least one joint portion to be butt-joined is formed into a thin plate shape over a predetermined length, and (b) the first ferrite block And a second ferrite block are butt-joined to each other to form a gap bar, and a reinforcing glass for joining the first ferrite block and the second ferrite block to the inside of the butt-joint portion formed into the thin plate shape. A step of forming
(C) A sliding surface of the gap bar is etched so that a track portion having a magnetic gap and a predetermined length up to the track portion are formed at a butt joint portion between the first ferrite block and the second ferrite block. By forming the connection magnetic path of the above, the track portion and the connection magnetic path on at least one side of the first ferrite block and the second ferrite block are formed by the butt joint portion formed into the thin plate shape. , Having a plate-like shape with a predetermined thickness protruding above the reinforced glass,
In addition, on both sides in the width direction of the track portion and the connecting magnetic path, the step of exposing the reinforcing glass to the sliding surface, and (d) from the gap bar subjected to the etching operation, the track portion and the connecting magnetic path, respectively. A method of manufacturing a magnetic head core including a step of cutting out a magnetic head core having a final shape having the above is also a feature thereof.

[0009]

In other words, in the magnetic head core having the structure according to the present invention, the member strength of the butt joint between the first ferrite member and the second ferrite member on the sliding surface side is substantially Since the magnetic path at the butt-jointed portion can be sufficiently thinned on the reinforcing glass member since it is to be exhibited by the reinforcing glass member, glass on both sides of the magnetic path can be formed. Since the member is exposed and the widthwise dimension thereof is reduced, the reduction of the cross-sectional area of the magnetic path can be achieved very effectively.

Therefore, in the magnetic head core according to the present invention, it is possible to sufficiently reduce the inductance while ensuring the sufficient core strength, thereby increasing the height of the magnetic recording medium. It is possible to easily cope with the increase in recording density.

According to the method of the present invention, as described above,
It is of course possible to advantageously manufacture a core for a magnetic head which can achieve a high degree of both core strength and low inductance characteristics, and in addition to that, a track portion and a connecting magnetic path are formed by an etching operation on a gap bar. Therefore, the shapes of the track portion and the connecting magnetic path can be determined with high precision, the design of the planar shape can be easily changed, and the inductance can be easily tuned by changing the magnetic path cross-sectional area. The effect of being able to do it can also be exhibited.

[0012]

The embodiments of the present invention will now be described in detail with reference to the drawings in order to clarify the present invention more specifically. In this embodiment, a specific example of the present invention applied to a monolithic core slider used in a magnetic head for RDD as shown in FIG. 6 will be described.

First, when obtaining a target magnetic head core slider, a first ferrite block 10 for providing a slider body and a second ferrite block 12 for providing a yoke portion are prepared as in the conventional case. . Incidentally, these first and second ferrite blocks 10, 1
2 has a size capable of cutting out a plurality of core sliders. The first and second ferrite blocks 10 and 12 are preferably made of a conventionally known ferrite material having a high magnetic permeability, for example, a single crystal material such as Mn-Zn ferrite or Ni-Zn ferrite. Used for.

The abutting surfaces of the first and second ferrite blocks 10 and 12 are respectively
Grooves are machined in the same manner as in the prior art to form the coil winding grooves 14 and 16.

Further, the second ferrite block 12 is further grooved in the abutting portion with respect to the first ferrite block 10 on the side constituting the sliding surface of the magnetic recording medium (upper surface side in the figure). Made, butt groove 1
7 are formed. That is, by this butt groove 17,
The abutting portion is a flat plate-shaped abutting plate portion 18 thinned over a predetermined length L.

The first ferrite block 10 is further tapered on the abutting surface for the second ferrite block 12 on the side constituting the sliding surface of the magnetic recording medium. The butted portion of the second ferrite block 12 with respect to the butted plate portion 18 is thinned.

Then, each of the first and second ferrite blocks 10 and 12 has its abutting surface polished according to a conventional method, and at least one of the first and second ferrite blocks 10 and 12 is polished. A gap spacer made of a non-magnetic material such as SiO ₂ or Al ₂ O _{3 is formed} on one of the polished surfaces by sputtering or the like with a thickness corresponding to the gap length of the target core slider. Further, after glass for bonding is applied to at least one of the abutting surfaces of the first and second ferrite blocks 10 and 12, they are butted and the glass for bonding is heated and melted. Due to
To be joined. This results in, as shown in FIG.
A gap bar 20 is formed.

Further, the gap bar 20 is provided with respect to the inner portion of the butting plate portion 18 of the first ferrite block 10 at the same time as or after the first and second ferrite blocks 10 and 12 are joined. The glass is melt filled. As a result, as shown in FIG. 2, the inner side of the butt plate portion 18 is located across the joint portion between the first ferrite block 10 and the second ferrite block 12, and they are connected to each other. Reinforced glass 22
However, it is formed with a thickness sufficient to substantially fill the butt groove 17.

When the reinforcing glass 22 is formed after joining the first and second ferrite blocks 10 and 12, the first and second ferrite blocks 1 are formed.
It is desirable to use glass having a softening temperature lower than that of the bonding glass of 0 and 12. Also, such a reinforcing glass 2
2 is one or both of the ferrite blocks 10 and 12 before joining the first and second ferrite blocks 10 and 12.
It may be poured into the joint portion 12 and melted before use.

After that, the gap bar 20 thus formed has an air bearing for the sliding surface 24 for the magnetic recording medium in order to obtain a desired core slider as shown in FIG. Section 26, track section 28
And the connection magnetic path 30 (see FIG. 6) is formed. The air bearing portion 26 and the like can be formed by machining, but it is preferably performed by a chemical etching method using a predetermined mask material or a laser induced etching method.

That is, for example, when the air bearing portion 26 and the like are formed by mask formation using a photoresist and a chemical etching method, first, the sliding surface 24 of the gap bar 20 is mirror-polished. Then, the processing distortion of the mirror surface is removed. By the polishing process, the butt plate portion 1 of the second ferrite block 12 is
Although the thickness of the butt plate 8 is determined, the butt plate portion 18 has the track portion 28 and the connecting magnetic path 3 as described later.
0 is formed, and its thickness is determined according to the magnetic characteristics and the like required for the intended core slider, but it is usually 10 to 30 μm.

Next, as shown in FIG. 3, the photoresist is patterned on the sliding surface 24, so that the photoresist pattern 34 for providing the target track portion 28 is formed into the first and second photoresist patterns 34. A photoresist pattern 36 for providing the air bearing portion 26 and a connecting magnetic path 30 are formed so as to extend over the ferrite blocks 10 and 12 and to be continuous with the photoresist pattern 34 for providing the track portion 28. The photoresist pattern 38 is the first ferrite block 1
They are formed on the 0 side and the second ferrite block 12 side, respectively.

The resist pattern 38 that provides the connection magnetic path 30 is set to have a predetermined dimension longer than the length L of the abutting plate portion 18. Further, in this embodiment, the photoresist pattern 38 that provides the connection magnetic path 30 has a triangular planar shape that gradually narrows toward the photoresist pattern 34 side that provides the track portion 28 on the butt plate portion 18, It is formed.

Next, the sliding surface 24 of the gap bar 20 provided with the photoresist pattern as described above is subjected to a chemical etching treatment in a phosphoric acid-based aqueous solution, so as shown in FIGS. As described above, the track portion 28 having the magnetic gap 40, the air bearing portion 26, and the connecting magnetic path 30 are each formed on the sliding surface 24 in a protruding form.

Here, the etching process is
The abutting plate portion 18 of the second ferrite block 12 is removed at a portion where the photoresist pattern is not formed, and the reinforcing glass 22 is etched at such a portion with an etching amount that is exposed to the sliding surface 24 side. To be done. That is, as a result, a magnetic circuit is constituted only by the track portion 28 and the connecting magnetic path 30 at the joining portion of the second ferrite block 12 to the first ferrite block 10 on the sliding surface 24 side.

Further, the above-mentioned etching treatment was previously conducted by the present applicant in order to prevent local non-uniformity of etching and improve the accuracy of the pattern.
As disclosed in No. 1, while the gap bar 20 is swung so as to move an arbitrary point on the single crystal plane in a random direction in a plane including the single crystal plane to be etched, It is desirable to stir the phosphoric acid-based aqueous solution by stirrer arranged above the single crystal plane.

Then, after the photoresist is removed,
By cutting the gap bar 20, the intended monolithic core slider 42 is completed, as shown in FIG. 6, in which an annular magnetic circuit is formed by the slider body 44 and the yoke portion 46. Is done.

That is, in the core slider 42 thus obtained, as shown in FIGS. 4 and 5, the joining portion of the second ferrite block 12 to the first ferrite block 10 on the sliding surface 24 side. However, in terms of member strength, the reinforcing glass 22 is used, and the reinforcing glass 22 exerts the strength of the joint portion.

Then, the magnetic path of the joint portion of the second ferrite block 12 to the first ferrite block 10 is formed by the thin plate-structured connecting magnetic path 30 placed on the reinforcing glass 22, and the connection is made. By exposing the reinforcing glass 22 on both sides of the magnetic path 30 in the width direction, the cross-sectional area of the magnetic path in the joint portion can be set to be extremely small over a predetermined length: L.

Therefore, in such a core slider 42 as described above, it is possible to reduce the inductance while sufficiently securing the core strength, and thereby easily deal with the high recording density of the magnetic recording medium. You can do it.

Further, according to the manufacturing method as described above, since the connection magnetic path 30 is formed by the etching operation on the gap bar 20 after the first and second ferrite blocks 10 and 12 are joined, the connection magnetic path 30 is formed. The magnetic path 30 can be formed with excellent dimensional accuracy, its planar shape can be easily changed, and the effect of easily tuning the inductance by changing the magnetic path cross-sectional area is also exhibited. To get.

The embodiments of the present invention have been described in detail above, but these are literal examples, and the present invention should not be construed as being limited to such specific examples.

For example, the length L of the butt plate portion 18 in the second ferrite block 12 and the thickness thereof, and the planar shape of the connecting magnetic path 30 depend on the desired characteristics of the core slider and the like. Should be set appropriately,
It is not limited.

Furthermore, in the above-described embodiment, the track portion 28 and the connecting magnetic path 30 are formed in a thin plate-like structure in which the track portion 28 and the connecting magnetic path 30 are formed so as to project above the reinforcing glass 22 only on the second ferrite block 12 side. However, in addition to or instead of this, it is of course possible to form the track portion and the connecting magnetic path of such a thin plate-like structure on the first ferrite block 10 side, and by doing so, The same effect as that of the embodiment can be effectively achieved.

Incidentally, as another embodiment of the present invention, the track portion 28 is thinned also on the first ferrite block 10 side, and the thin plate-shaped connecting magnetic path 30 is also provided on the first ferrite block 10 side. The specific structure of the magnetic head core having the structure thus formed is shown in FIGS. Incidentally, in the present embodiment, in the figure, for the members and parts having the same structure as the first embodiment, by assigning the same reference numerals as the first embodiment,
Detailed description thereof will be omitted.

The present invention can also be applied to a magnetic head core (core chip) used in a composite type core slider, and further, as shown in FIG.
Cores for DD heads, not limited to core sliders or cores, VTR heads, FDD heads, DAT
It goes without saying that it can also be applied to a core for a magnetic head such as a magnetic head.

Although not listed one by one, the present invention is
Based on the knowledge of those skilled in the art, it can be carried out in various modified, modified, and improved modes, and
It goes without saying that all such embodiments are included in the scope of the present invention without departing from the spirit of the present invention.

[Brief description of drawings]

FIG. 1 is a process drawing for explaining an embodiment of a method for manufacturing a magnetic head core according to the present invention.

FIG. 2 is another process drawing for explaining the embodiment shown in FIG.

FIG. 3 is still another process drawing for explaining the embodiment shown in FIG.

FIG. 4 is an enlarged plan view of an essential part showing an embodiment of a magnetic head core having a structure according to the present invention.

5 is a sectional view taken along line VV in FIG.

FIG. 6 is a perspective view showing an embodiment of a magnetic head core having a structure according to the present invention.

7 is a plan view corresponding to FIG. 4, showing a magnetic head core as another embodiment of the present invention.

8 is a sectional view taken along line VIII-VIII in FIG.

[Simple explanation of symbols]

 10 First Ferrite Block 12 Second Ferrite Block 14, 16 Coil Winding Groove 17 Butt Groove 18 Butt Plate 20 Gap Bar 22 Reinforced Glass 24 Sliding Surface 26 Air Bearing 28 Track Part 30 Connection Magnetic Path 40 Magnetic Gap 42 core slider

Claims (2)

[Claims] 1. A first and a second ferrite member are integrally butt-joined to each other to form an annular closed magnetic path, a part of the outer peripheral surface of which constitutes a sliding surface of a magnetic recording medium. And a magnetic head core having a track portion having a magnetic gap formed at the butt joint portion on the sliding surface side of the second ferrite member, at least one of the joint portions of the first and second ferrite members A reinforcing glass member is arranged on the ferrite member side, and the track portion formed on at least one side of the first ferrite member and the second ferrite member and a connecting magnetic path of a predetermined length leading to the track portion. Is formed into a plate-like shape having a predetermined thickness protruding above the reinforcing glass member, and the reinforcing portions are provided on both sides in the width direction of the track portion and the connecting magnetic path. Core for a magnetic head, characterized in that the lath member was allowed exposed on the sliding surface side. 2. At least one of the butt-joined parts on the sliding surface side forms a ring-shaped closed magnetic path forming a sliding surface of the magnetic recording medium by butt-joining each other. The step of preparing the first ferrite block and the second ferrite block in which the joint portion on the side has a thin plate shape over a predetermined length, and butt-joining the first ferrite block and the second ferrite block. A gap bar is formed with the step of forming a reinforcing glass for joining the first ferrite block and the second ferrite block inside the thin plate-shaped butt joint portion, and Etching the sliding surface to have a magnetic gap at the butt joint between the first ferrite block and the second ferrite block. By forming a track portion and a connecting magnetic path having a predetermined length to reach the track portion, the track portion and the connecting magnetic path on at least one side of the first ferrite block and the second ferrite block, The thin-plate-shaped butt-joint portion is configured to have a plate-like shape with a predetermined thickness protruding above the reinforcing glass, and on both sides in the width direction of the track portion and the connecting magnetic path,
And a step of exposing the reinforcing glass to the sliding surface, and a step of cutting a final-shaped magnetic head core having the track portion and the connecting magnetic path from the gap bar subjected to the etching operation. A method of manufacturing a core for a magnetic head, comprising: