JPS61264502A - Magnetic head and its production - Google Patents

Abstract

PURPOSE:To improve the dimensional accuracy and wear resistance of a gap size and to reduce the cost of production by forming a polycrystalline core for either one of the cores along the traveling direction of a recording medium with a gap as a boundary and a single crystal core for the other side and forming the gap to the single crystal core. CONSTITUTION:The polycrystal C-shaped core 31 formed of an Mn-Zn ferrite polycrystal material and the single crystal are disposed to face each other along the traveling direction (arrow A) of the recording medium. Glass 33 is interposed between the ends of these two cores and is melted and welded, by which the gap (g) is formed. The cores 31 and 32 are fixed to each other, by which the head is formed to the prescribed thickness. A surface 30a having the gap (g) is formed as the traveling surface of the core 30 to face the recording medium.

Description

[Detailed description of the invention] [Table of contents] - Overview - Field of industrial application - Conventional technology [Figures 5 and 6 (first conventional example, Figures 7 and 8)
2nd Conventional Example)] ・Problems to be solved by the invention, means, effects, and embodiments for solving the problems (Figures 1.2 and 3.4) ・Effects of the invention [Summary] Magnetic head The structure of the running surface of the core that faces the magnetic medium that constitutes the magnetic circuit is such that one side of the gap is a polycrystalline core and the other side is a single-crystalline core, and a gap is formed in this single-crystalline core. By configuring this, it is possible to improve gap dimensional accuracy and wear resistance, and to reduce manufacturing costs.

[Industrial application field]

The present invention relates to a magnetic head and a method of manufacturing the same, and more particularly to the structure of a core constituting a magnetic circuit of a magnetic head suitable for floppy disk drives and the method of manufacturing the same.

Generally, a magnetic head has a core that constitutes a magnetic circuit, and a minute gap (for example, 1 to 5 μm) is formed between the core.
A coil is wound around the core, and this gap is arranged to face the magnetic recording medium to record and read information. That is, by passing a signal current of high or low strength through the coil, magnetic flux is generated, information is recorded on the recording medium by leakage magnetic flux in the gap, and information is reproduced by the reverse operation. For this type of magnetic head, it is important that the dimensional accuracy of the gap (usually about ±0.1 to ±0.3 μm), good core wear resistance, and low manufacturing cost are important. . Recently, Mn--Zn ferrite polycrystals or single crystals have been frequently used as the core material. Polycrystalline is cheap but has the property of lacking workability and wear resistance, and -1 single crystal is expensive (polycrystalline 5-1
0 times), but has excellent workability and wear resistance.

[Conventional technology]

5 and 6 are diagrams for explaining the first conventional example. FIG. 5 is a front view of the first conventional example, and FIG. 2 is an explanatory diagram of the manufacturing method of the first conventional example. In both these figures, the symbol 1
0 indicates the entire core of the first conventional example, 11 is a C-shaped core, 12 is an I-shaped core, 13 is fused and fixed glass (non-magnetic material), 13-1 is bar-shaped glass before melting, and 14 is In the spacer, g indicates the gap (and its width dimension), and arrow A indicates the running direction of the recording medium (for example, a floppy disk).

As shown in FIG. 5, this first conventional (1o)
C-shaped core 1 formed together from Zn ferrite polycrystalline material
1 and a ■-shaped core 12 are placed facing each other, and a glass 13 is interposed between the ends of the two and melted and fixed, thereby forming a gap g and fixing the cores 11 and 12 to each other to a predetermined thickness. (thickness perpendicular to).

Next, a first conventional manufacturing method will be described with reference to FIG.

(a) First, the C-shaped core 11 and the I-shaped core 12 are connected to Mn −
It is made of Zn ferrite polycrystalline material and is formed into a long shape as shown in the figure.

(0) Next, the cores 11 and 12 are arranged facing each other, and the spacers 14 are interposed between the upper and lower ends and the longitudinal ends of the cores, and the cores 12 and 12 are fixed together. As a result, a combined body of cores 11 and 12 is formed. Note that this spacer 14 is formed precisely to the width dimension of the gap g. Therefore, a gap g is provided between the cores 11 and 12 by this spacer '14.

(/~, Next, a rod-shaped glass (non-magnetic material; shown by a dashed line in the figure) 13-1 is placed on the gap (g).

), then by melting the glass 13-1 in a heating furnace and flowing it into the gap, the cores 11 and 12 are melted.
to fix.

(=11, Next, the running surface 10a facing the recording medium (not shown) is finished smooth, and then the spacer 14
A predetermined cutting line (indicated by a two-dot chain line in the diagram)
15, it is divided into pieces and cut into predetermined thicknesses in the longitudinal direction.

Through the above steps, a core 10 as shown in FIG. 5 is formed. However, in this first conventional example (10), since the cores 11 and 12 facing the recording medium are both formed using polycrystalline material, the material cost is low, but on the other hand, There are disadvantages in that the dimensional accuracy of the gap g and the wear resistance of the running surface 10a are low.

7 and 8 are diagrams for explaining the second conventional example. FIG. 7 is a front view of the second conventional example, and FIG. 8 is an explanatory diagram of the manufacturing method of the second conventional example. In both these figures, the symbol 2
0 indicates the entire core of the second conventional example, 21 is a C-shaped core, 22 is a ■-shaped core, 23 is fused and fixed glass (non-magnetic material), 23-1 is a rod-shaped glass before melting, g is the gap (and its width dimension), arrow A is the recording medium (e.g.
The running direction of the floppy disk (not shown) is shown.

As shown in FIG. 7, this second conventional example (20) has Mn
- A C-shaped core 21 and a ■-shaped core 12, which are both formed from a Zn ferrite single crystal material, are arranged facing each other, and a glass 23 is interposed between the ends of these two and melted and fixed to form a gap g and the core 21 and 22 are fixed together to form a predetermined thickness (thickness in the vertical direction as viewed in the figure).

Next, a second conventional manufacturing method will be described with reference to FIG.

First, (as shown in Figure 81, a C-shaped core 21 is formed from Mn-Zn ferrite polycrystalline material, and an I-shaped core 22 is formed from Mn-Zn ferrite single crystal material.) These cores 21 and 22 are 1 It is formed into a long shape as in the case of the conventional example (FIG. 6).In this case, the abutting surface 21a of the core 21 and the abutting surface 22a of the core 22 are finished smooth with a polished ring. Then, core 21
A rod-shaped glass 2, which will be described later, is placed above the abutting surface 21a of the
An insertion groove 21b for inserting 3-1 is formed. On the other hand, a gap groove 22b for forming a gap g is formed on the upper part of the abutting surface 22a of the core 22 using an etching method, corresponding to the insertion groove 21b.

Next, as shown in Figure b1, the core 21 and the core 22 are fixed to each other using an acidic adhesive such as an acidic adhesive. A conjugate of 22 is formed.Then, this conjugate is heated in a constant temperature bath at a nitrogen atmosphere and at high temperature (approximately 1200 to 1300 °C) for a long time to perform a solid phase reaction process. In the reaction process, the polycrystalline core 21 changes to a single crystal.Thereby, both of the 9 combinations of cores 21 and 22 are formed as a single crystal.

Next, (as shown in Figure C1, the insertion groove 22b of the core 21
A rod-shaped glass (non-magnetic material) 23-1 is inserted and arranged inside.

Next, as shown in FIG. are fixed to each other. Reference numeral 23 indicates glass that has been melted and fixed.

Next, as shown in Figure C1, cut along the cutting line 24 in Figure d1 (indicated by a two-dot chain line in the figure), and this cut surface,
That is, a running surface 20 facing a recording medium (not shown)
A is finished smooth by polishing or the like, and then the combined body of cores 21 and 22 is cut into pieces of predetermined thickness along the longitudinal direction.

Through the above steps, the core 20 shown in FIG. 7 mentioned above is formed.

However, in this second conventional example (20), since the cores 21 and 22 on the running surface 20a facing the recording medium are both formed of Mn-Zn ferrite single crystal, the dimensional accuracy of the gap g and the wear resistance are poor. Although it has the advantage of being good, it has the disadvantage that the production cost is high because it requires a solid phase reaction step in the production process.

[Problem to be Solved by the Invention 3] As explained above, in the first conventional example (Figs. 5 and 6), the C-shaped core (11) and the ■-shaped core (12) facing the recording medium are Since both are made of polycrystalline material, they have the advantage of low material costs, but on the other hand, they have the problem of lacking dimensional accuracy of the gap g and lack of wear resistance of the running surface (10a). In addition, the second conventional example (seventh,
8), a C-shaped core (21
) and the I-shaped core (22) are both made of single crystal material, so the dimensional accuracy of the gap (g) and the running surface (2
0a) has the advantage of good wear resistance, but
In the manufacturing process, there is a problem in that the manufacturing cost is high because a solid phase reaction step is required.

The present invention was created in view of these problems, and the structure of the core on the running surface of the core facing the recording medium is such that one core is made of a polycrystalline material and the other core is made of a single crystal material, with a gap as a boundary. To provide a magnetic head which has better gap dimensional accuracy and wear resistance than the first conventional example and is cheaper than the second conventional example by forming a gap in the single crystal material. The purpose is to

[Means for solving problems]

In order to solve the above problems, in the present invention, in a magnetic head that records and reproduces information on a magnetic recording medium, a running surface of a core 30 that constitutes a magnetic circuit of the magnetic head faces the recording medium. The structure of 30a is such that one side along the running direction of the recording medium is a polycrystalline core 31 and the other side is a single-crystalline core 32, with the recording/reproducing gap g as a boundary, and the single-crystalline core 32 The present invention is characterized in that the gap g is formed in the gap g.

Further, in the present invention, there is provided a gap g for recording/reproducing that faces the magnetic recording medium and along the running direction of the recording medium.
A polycrystalline core 31 and a single-crystalline core 3 are arranged opposite to each other via
2 and a core 3 constituting a magnetic circuit of the magnetic head.
In the manufacturing method of No. 0, (a) an insertion groove 31b for a non-magnetic material 33-1 is formed in the abutting surface 31a of the polycrystalline core 31, and the single-crystalline core 3
A gap groove 32b for forming the gap g is formed in the abutting surface 32a of the two by an etching method so that a part thereof can communicate with the insertion groove 31b, and (0) next, the polycrystalline core 31 and the single The crystal core 32 is connected to its abutting surface 3
1a and b are fixed to form a combined body of these two, and then a non-magnetic material 33-1 is inserted and arranged in the insertion groove 31a, and (i) next, the combined body is heated to form a combined body of the non-magnetic material 33. 1 to 1 is melted and allowed to flow into the gap groove 32b and fixed, and 2) is cut along the cutting line 34 passing through the gap groove 32b and the polycrystalline core 31 and the single crystal core 32, and this cut surface is is the running surface 30 of the core 30 facing the recording medium.
There is provided a method for manufacturing a magnetic head characterized in that (a) the magnetic head is finished smoothly.

The polycrystalline core 31 is a Mn-Znn fusite polycrystalline core, and the single-crystalline core 32 is a Mn-Zn fusite polycrystalline core.
It is preferable that the nonmagnetic material 33-1 is a ferrite single crystal core and that the nonmagnetic material 33-1 is a low melting point glass.

[For production]

As described above, by forming a polycrystalline core on one side along the running direction of the recording medium and a single-crystalline core on the other side with the gap g as a boundary, and forming a gap in the single-crystalline core, gap dimensional accuracy and It is possible to improve wear resistance and reduce manufacturing costs.

〔Example〕

1 to 4 are diagrams for explaining the present invention in detail, FIG. 1 is a front view of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of a manufacturing method of the embodiment of the present invention. . In these figures, reference numeral 30 indicates the entire core which is an embodiment of the present invention,
30a is a running surface of a core (30) that faces the running surface of a recording medium (not shown), 31 is a C-shaped core, 32 is an I-shaped core,
33 is glass that has been melted and fixed (low melting point glass; non-magnetic material), 33-1 is bar-shaped glass before melting, g is a gap (and its width dimension), and arrow A is a recording medium (for example, a floppy disk, not shown) ) respectively indicate the running direction.

As shown in FIG. 1, in this example (30), Mn-Z
Polycrystalline C-type core 3 formed from n-ferrite polycrystalline material
1 and a single-crystal square-shaped core 32 formed from a Mn-Zn ferrite single crystal are arranged facing each other along the running direction of the recording medium (arrow A), and a glass 33 is placed between the ends of the two.
are interposed and melted and fixed to form a gap g, and the cores 31 and 32 are fixed to each other to have a predetermined thickness (thickness in the vertical direction toward FIG. 1), and a surface having the gap g. 30a is formed as a running surface of the core 30 facing the recording medium.

Next, the manufacturing method of this embodiment (30) will be explained with reference to FIG.

First, as shown in FIG. This core 31
, 32 are the aforementioned 1. Like the second conventional example, it is formed in an elongated shape. In this case, the abutting surface 31a of the core 31,
The abutting surface 32a of the core 32 is finished smooth with a polished ring. An insertion groove 31b for inserting a rod-shaped glass 33-1, which will be described later, is formed in the upper part of the abutting surface of the core 31.

On the other hand, a gap groove 32b for forming a gap g is formed above the abutting surface 32a of the core 32 by using an etching method, the gap groove 32b being partially in communication with the insertion groove 31b.

Next, as shown in the figure, the cores 31 and 32 are butted against each other at their abutting surfaces 31a and 31b, and they are fixed to each other using an adhesive (for example, nitric acid, etc.). As a result, core 31
and 32 conjugates are formed. Following this, the rod-shaped glass 33-1 is inserted into the insertion groove 31b and the lower corner.

Next, as shown in Figure (C), the combined body in Figure (b) is heated in a heating furnace (approximately 700°C to 800°C) to melt the rod-shaped glass 33-1 in Figure (b) and create a gap. The melted and fixed glass 33 flows into the groove 32b to fix the cores 31 and 32 to each other, and the gap groove 32b is filled with the molten fixed glass 33.

Next, as shown in Figure d1, cut from the cutting line 34 in Figure C1 (indicated by a two-dot chain line in the figure), and cut this cut surface, that is, the running surface 30a facing the recording medium (not shown). A smooth finish is achieved by polishing or the like.Then, the combined body of the cores 31 and 32 is cut into pieces along cutting lines (two-dot chain lines) 35 that are divided into predetermined thicknesses along the longitudinal direction.

Through the above steps, the core 30 shown in FIG. 1 mentioned above is formed.

In this way, in this embodiment (30), the core 31 on the running surface 30a is polycrystalline to reduce the material cost, the core 32 is monocrystalline to improve wear resistance, and the single crystal core 32 A gap groove 32b is provided to form a gap g to ensure its dimensional accuracy, and furthermore, with this configuration, it is possible to simplify the manufacturing process (reduce the number of solid phase reaction steps) and reduce the manufacturing cost. In this embodiment, it is of course possible to form the core 31 as a single crystal and the core 32 as a polycrystal, contrary to the above. However, in this case, a gap g is formed in the core 31 which is a single crystal. In any case, it is preferable that the smaller volume of the cores 31 and 32 be made of a single crystal.

FIGS. 3 and 4 are diagrams for explaining the workability of this example, and are diagrams showing the surface roughness of Mn--Zn ferrite single crystal and polycrystal before etching treatment, respectively. As can be seen from FIG. 3, the maximum height of the surface roughness of a single crystal is about 0.05 μm, and as seen from FIG. 4, the maximum height of the surface roughness of a polycrystal is about 0.5 μm.

When these single crystals and polycrystals were subjected to phosphoric acid etching under the same conditions at a humidity of 80°C and a time of 20 minutes, the maximum surface roughness of the single crystals was approximately 0.05 μm.
The maximum height of the surface roughness of the polycrystal is about 0.5 μm.

As described above, when polycrystals and single crystals are etched, the polycrystals have grains (coarse grains) and the surface roughness becomes large, whereas the single crystals have no grains and therefore have a small surface roughness. However, in the case of polycrystalline material, the surface roughness can be reduced by further mirror-polishing it, but this increases the processing cost. Therefore, in this embodiment (30), a gap (g) that requires dimensional accuracy is formed by etching in the single crystal core (32) by utilizing the properties (processability) of both, and the other The core (31) is made of inexpensive polycrystalline material.

〔Effect of the invention〕

As described above, according to the present invention, the structure of the core on the core running surface facing the recording medium is made of a polycrystal on one side and a single crystal on the other with a gap as a boundary, and a gear is formed in this single crystal. By adopting this configuration, the wear resistance and the dimensional accuracy of the gap can be significantly improved compared to the first conventional example in which both the cores on both sides of the gap are polycrystalline. This has the remarkable effect of reducing the core material cost and manufacturing cost (reducing the solid phase reaction process) compared to the conventional example, and improves gap dimensional accuracy, wear resistance, price, etc. , it is possible to realize a magnetic head that is optimal for floppy disk devices and the like.

[Brief explanation of the drawing]

FIG. 1 is a front view of the embodiment (30) of the present invention, FIG. 2 is an explanatory diagram of the manufacturing method of the embodiment of the present invention, and FIGS. 3 and 4 are diagrams for explaining the present invention in detail. , Fig. 3 is a diagram showing the surface roughness of Mn-Zn ferrite single crystal, Fig. 4 is a diagram showing the surface roughness of Mn-Zn ferrite polycrystal, and Fig. 5 is a front view of the first conventional example (10). 6 is an explanatory diagram of the manufacturing method of the first conventional example, FIG. 7 is a front view of the second conventional example (20), and FIG. 8 is an explanatory diagram of the manufacturing method of the second conventional example. In FIGS. 1 and 2, 30 is an embodiment of the present invention (core), 30a is a running surface of the core (30) facing the recording medium, and 3
1 is a C-shaped core (polycrystalline), 31a is a butting surface, 31b is an insertion groove, 32 is an I-shaped core @ Yushima, 32a is a butting surface, 32b is a gap groove, 33 is a fused glass (non-bonded) (magnetic material), 33-1 is a rod-shaped glass before melting, 34 and 35 are cutting lines, and g is a gap.Front view 30a of the embodiment (30) of the present invention... Running surface facing the recording medium 31...Mn
-zn ferrite polycrystalline core (C type) 32...Mn-
Zn ferrite single crystal core (■ shape) 33...Fused and fixed glass 9...Gap A...Strike direction of recording medium 31G, :3'2G...Abutting surface M low Zn ferrite single crystal Fig. 3 Diagram showing the surface roughness of Mn-Zn ferrite polycrystal Fig. 4 Diagram showing the surface roughness of Mn-Zn ferrite polycrystal Fig. 6 - Front view of the second conventional example (20) Fig. 7 Manufacturing power of the second conventional example Fig. 8 21G, 22a...Abutment surface 2+b...Insertion Groove 22b... Gap groove removal explanatory diagram

Claims (1)

[Claims] 1. In a magnetic head for recording and reproducing information on a magnetic recording medium, a traveling unit (30a) of a core (30) forming a magnetic circuit of the magnetic head faces the recording medium. A polycrystalline core (31) is formed on either side along the running direction of the recording medium with the recording/reproducing gap (g) as a boundary.
, the other side is a single crystal core (32), and the single crystal core (
32) A magnetic head characterized in that the gap (g) is formed in the magnetic head. 2. The polycrystalline core (31) is a Mn-Zn ferrite polycrystalline core, and the single-crystalline core (32) is a Mn-Zn ferrite polycrystalline core.
The magnetic head according to claim 1, which is a ferrite single crystal core. 3. Comprising a polycrystalline core (31) and a single-crystalline core (32) facing the magnetic recording medium and facing each other along the running direction of the recording medium with a recording/reproducing gap (g) interposed therebetween. In the method for manufacturing a core (30) constituting a magnetic circuit of a magnetic head, (a) a butting surface (31a) of the polycrystalline core (31);
) for forming an insertion groove (31b) for the non-magnetic material (33-1), and a gap groove (32b) for forming the gap (g) in the abutting surface (32a) of the single crystal core (32).
) is formed by an etching method so that a part thereof can communicate with the insertion groove (31b), (b), next, the polycrystalline core (31) and the single crystal core (
32) by abutting and fixing their abutting surfaces (31a, 32a) against each other to form a combined body of the two, and then inserting and arranging the non-magnetic material (33-1) into the insertion groove (31a), (c) Next, the combined body is heated, and the non-magnetic material (3) is heated.
3-1) is melted and allowed to flow into the gap groove (32b) and fixed, and (d) the gap groove (32b) and the polycrystalline core (31) and single crystal core (32) are bonded together. Cutting line (34
) and finishing the cut surface smoothly as a running surface (30a) of the core (30) facing the recording medium. 4. The polycrystalline core (31) is a Mn-Zn ferrite polycrystalline core, and the single-crystalline core (32) is a Mn-Zn ferrite polycrystalline core.
4. The method of manufacturing a magnetic head according to claim 3, wherein the non-magnetic material (33-1) is a low melting point glass.