JPH08221707A - Production of magnetic head - Google Patents

Abstract

PURPOSE: To improve yield and to stabilize head characteristics in a process for producing a magnetic head of a double gap type. CONSTITUTION: A groove part for insertion of a central core is formed at the center in the process for producing magnetic head of a double gap type formed by joining the side cores across the magnetic gap to both sides of the central core. Side core blocks 34 having stepped parts 32, 33 formed are formed at both ends in the extension direction of this groove part. The central core is inserted into the groove parts of the side core blocks 34 and is joined by a gap forming material. The gap forming material 36 flowing out at the time of this joining is accumulated in the stepped parts 32, 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a magnetic head. More specifically, the present invention relates to a method for manufacturing a double gap type magnetic head.

[0002]

2. Description of the Related Art A magnetic head, for example, in the erasing magnetic head, as shown in FIG. 8, for example, on opposite sides of the center core 2 of ferrite, across the respective magnetic gaps g ₁ and g _2, each side cores of the same ferrite A so-called double-gap type erasing magnetic head 1 formed by joining 3 and 4 has been proposed. In the illustrated example, the central core 2 and the side cores 3,
A front core portion 7 formed of 4 and a back core portion 8 formed of an E-shaped core 5 are magnetically and mechanically joined to form a closed magnetic circuit, and a bobbin provided with a winding 6 is attached to the back core portion 8. Consists of

This double-gap type erasing magnetic head 1 is excellent in erasing efficiency because the erasing operation is continuously performed by the first and second magnetic gaps g ₁ and g ₂ , and is currently most widely used. ing.

9 to 12 show a method of manufacturing a conventional double-gap type erasing magnetic head. First, as shown in FIG. 9A, a side core block 12 made of a magnetic material such as ferrite and having a groove 11 for inserting a central core formed by cutting is formed in the center. The side core block 12 is formed by forming the groove 11 and then cutting each head in the extending direction of the groove. For this side core block 12, a central core 2 made of the same magnetic material as that of the side core block and a gap forming material such as fused glass 13 are prepared.

As shown in the sectional structure of FIG. 9B, the side core block 12 has a groove portion 11 into which the central core 2 is inserted.
In addition to the above, a gap forming groove portion (so-called step) 14 and a fused glass insertion groove portion 15 gradually widening toward the upper surface are integrally formed. The widths a ₁ and a _{2 of the} gap forming groove portion 14 become the magnetic gap length when the head is completed.

Next, the central core 2 is inserted into the groove 11 for inserting the central core of the side core block 12, the fused glass 13 is placed in the groove 15, and then heated and melted as shown in FIG. 10C. The glass 13 is poured into the gap forming groove 14, and at the same time, the central core 2 and the side core block 12 are joined and united by the glass 13. FIG. 10D shows a sectional structure in a state where the central core 2 and the side core block 12 are joined by the glass 13.

Next, after the side core block 12 in which the central core 2 is integrated, the joint surface 16 with the back core is polished, and then cylindrically polished to the position of the chain line 17 in FIG. The sliding surface 18 is formed to have the central core 2 shown in FIG. 11E and side cores 3 and 4 on both sides thereof.
The front core portion 7 facing the _two magnetic gaps g ₁ and g ₂ is formed at 8.

Next, as shown in FIG. 11F, after mounting the bobbin 19 in which the winding 6 is wound on the back core portion 8 made of, for example, an E-shaped ferrite core, the front core portion 7 and the back core portion 8 are bonded. Bond with a chemical agent.

In this way, the double gap type erasing magnetic head 1 shown in FIG. 12 is obtained. The erasing magnetic head 1 is placed in a shield case and completed.

[0010]

In the conventional method of manufacturing a magnetic head described above, when the central core 2 and the side core blocks 12 are fused, as shown in FIG.
The molten glass 13 leaks out to both end faces 12A and 12B of the side core block 12 in the groove extension direction, and for this reason, as shown in FIG. Block bottom surface 12C
The molten glass 13 enters between the two, and in the worst case, the board 20 and the side core block 12 are fused. Of course,
In this case, it cannot be used as a head and becomes defective.

Also, the side core block 1 is not required to be fused.
Since the glass 13 flowing between the board 2 and the board 20 changes the height h of the side core block 12, it affects the processing dimensional accuracy after fusion, and the magnetic gap depth (depth) of the magnetic head is increased. Dispersion and instability in head characteristics.

In view of the above points, the present invention provides a method of manufacturing a magnetic head which improves the yield of good products in manufacturing and has stable head characteristics.

[0013]

According to the present invention, there is provided a method of manufacturing a double-gap type magnetic head in which a side core is joined to both sides of a central core with a magnetic gap sandwiched between the central core and a side having a groove portion for inserting the central core. When the core block is formed, stepped portions are formed at both ends of the side core block in the groove extension direction.

[0014]

In the present invention, the step portions are formed at both ends of the side core block in the groove extension direction, so that when the central core and the side core block are joined by the gap forming material,
The gap forming material that has flowed out to both end surfaces of the side core block is
It collects on the stepped portion and does not go around to the lower surface of the side core block. Therefore, the yield of non-defective products is improved, the dimensional variation of the height of the side core block is reduced, and the head characteristics are stabilized.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a magnetic head according to the present invention is a method of manufacturing a double-gap type magnetic head in which side cores are joined to both sides of a central core with a magnetic gap interposed therebetween.
A step of forming a central core insertion groove at the center and forming side core blocks with stepped portions at both ends in the extension direction of the groove, and inserting the central core into the groove of this side core block and using a gap forming material. It is characterized by having a step of joining.

The height of the step portion can be set lower than the height from the lower surface of the side core block to the bottom surface of the groove portion for inserting the central core.

The length of the step portion in the groove extension direction is
It can be set to 0.1 mm or more.

Embodiments of the present invention will be described below with reference to the drawings.

The present embodiment is applied to the production of a double gap type erasing magnetic head. First, as shown in FIG. 1A, for example, a groove 31 for inserting a central core is formed by cutting in a magnetic material such as ferrite, and a step portion 32 is formed at both ends in the extension direction of the groove 31.
The side core block 34 formed by cutting 33 is formed. For this side core block 34, a central core 35 made of the same magnetic material as the side core block, for example, ferrite, is used.
A fused glass 36, which is a gap forming material, is prepared.

As shown in the sectional structure of FIG. 1B, the side core block 34 has a groove portion 3 into which the central core 35 is inserted.
1, a gap forming groove portion (so-called step) 37 and a fused glass insertion groove portion 38 gradually widening toward the upper surface are integrally formed.

In the step portions 32 and 33 at both ends of the side core block 34, as shown in FIG. 2C, the groove portion 31 is formed.
The length l protruding in the extension direction of 0.1 mm or more (l ≧
0.1 mm) and set its height F to the side core block 3
Height H from the lower surface 32C of 1 to the bottom surface 31a of the groove 31
The following (F ≦ H) is set.

If the length l is shorter than 0.1 mm, the effect of accumulating, for example, molten glass, which will be described later, as a gap forming material is reduced, and the effect of preventing glass from leaking is reduced.
In addition, the height F of the step portions 32 and 33 is the bottom surface 31 of the groove portion 31.
When the height is higher than the height a up to a, the effect of collecting the flowing glass is lost.

As shown in FIG. 2D, the side core blocks 32 and 33 are cut using a grinding wheel 40 for each head. By forming the shape of the grinding wheel 40 at this time as shown in FIG. , The stepped portion 3 at the same time when cutting each block
2,33 can be processed.

Then, the central core 35 is inserted into the groove 31 for inserting the central core of the side core block 34, the fused glass 36 is placed in the groove 38, and then heated and melted as shown in FIG. 3E. The glass 36 is poured into the gap forming groove 37, and at the same time, the central core 35 and the side core block 34 are joined and united by the glass 36. FIG. 3F shows a sectional structure in a state where the central core 35 and the side core block 34 are joined by the glass 36.

Next, with respect to the side core block 34 in which the central core 35 is integrated, the joint surface 41 with the back core is formed.
3G, and then cylindrically polished to the position of the chain line 42 in FIG. 3F to form the sliding surface 43 of the recording medium, and having the central core 35 shown in FIG. 4G and side cores 44 and 45 on both sides thereof. A front core portion 47 facing the _two magnetic gaps g ₁ and g ₂ is formed on the sliding surface 43.

Next, as shown in FIG. 4H, the back core portion 4 made of, for example, an E-shaped ferrite core which is a magnetic material core.
After mounting the bobbin 50 on which the winding 49 is wound, the front core portion 47 and the back core portion 48 are bonded to each other with an adhesive or the like.

In this way, the double gap type erasing magnetic head 51 shown in FIG. 5 is obtained. The erasing magnetic head 51 is placed in the shield case and completed.

According to the manufacturing method of the present embodiment, when the side core blocks 34 are cut into blocks by the grindstone 40 at the same time, the step portions 32 and 33 are formed at the ends of the side core blocks 34 at the same time. After that, when the central core 35 and the side core block 34 are bonded and united by the fusion glass 36, the molten glass 36 is formed by forming the side core block 3
Although it flows out to the end face of No. 4, the glass 36 is stored in the step portions 32 and 33 as shown in FIGS. 6 and 7, and the side core block 34 is placed between the board 53 such as an iron plate and the lower surface 34C of the side core block 34. Never get in.

Therefore, the side core block 34 and the board 53
Are not fused, and the yield of non-defective products at the time of manufacturing is improved.

Further, when forming the front core portion,
Variations in the size of the height h of the side core block 34 mounted on the board 53 are reduced, variations in the head gap depth are eliminated, and the head characteristics are stabilized.

Generally, the higher the fusion temperature, the glass 36
However, the step portions 32 and 33 prevent the glass 36 from wrapping around, so that the degree of freedom in setting the fusion temperature is increased. When the fusion temperature is raised to facilitate the flow, it is possible to prevent the generation of bubbles in the magnetic gaps g ₁ and g ₂ .

In the above example, fused glass was used as the gap forming material, but other than that, resin can be used,
It is also possible to join the central core and the side core blocks by bonding with this resin.

The present invention can be applied not only to the erasing magnetic head but also to the manufacture of other double gap type magnetic heads.

[0034]

According to the method of manufacturing the double-gap type magnetic head according to the present invention, the step portions are formed at both ends in the groove extending direction of the side core block having the groove for inserting the central core. When the side core block and the central core are joined via the gap forming material, it is possible to prevent the gap forming material flowing out to the end face side from being accumulated in the step portion and entering the lower surface of the side core block. Therefore, the manufacturing yield can be improved, the variation in the gap depth can be reduced, and the head characteristics can be stabilized. Therefore, an accurate magnetic head can be manufactured with high yield.

Further, by setting the height of the stepped portion to be equal to or lower than the height from the lower surface of the side core block to the bottom surface of the groove portion for inserting the central core, it is possible to reliably collect the flowed gap forming material on the stepped portion. Therefore, it is possible to prevent the gap forming material from flowing out to the lower surface side.

Further, the length of the step portion in the groove extension direction is set to 0.
By setting the gap forming material to 1 mm or more, the gap forming material that has flowed out can be reliably accumulated on the step portion, and the gap forming material can be prevented from flowing out to the lower surface side.

[Brief description of drawings]

FIG. 1A is a manufacturing process diagram showing an embodiment of a method of manufacturing a magnetic head according to the present invention. B is a manufacturing process diagram illustrating an embodiment of a method of manufacturing a magnetic head according to the invention.

FIG. 2C is a manufacturing process diagram illustrating an embodiment of the method for manufacturing the magnetic head according to the present invention. D is a manufacturing process diagram showing an embodiment of a method of manufacturing a magnetic head according to the invention.

FIG. 3E is a manufacturing process diagram illustrating the embodiment of the method of manufacturing the magnetic head according to the invention. F is a manufacturing process diagram showing an embodiment of a method of manufacturing a magnetic head according to the invention.

FIG. 4 is a manufacturing process diagram showing an embodiment of a method of manufacturing a magnetic head according to the present invention. H is a manufacturing process diagram showing an embodiment of a method of manufacturing a magnetic head according to the invention.

FIG. 5 is a manufacturing process diagram showing an embodiment of a method of manufacturing a magnetic head according to the present invention.

FIG. 6 is a perspective view for explaining the present invention.

FIG. 7 is a side view for explaining the present invention.

FIG. 8 is a perspective view of a double-gap type erasing magnetic head.

FIG. 9A is a manufacturing process diagram illustrating the method of manufacturing the conventional magnetic head. B is a manufacturing process diagram illustrating a conventional method of manufacturing a magnetic head.

10A to 10C are manufacturing process diagrams showing a conventional method of manufacturing a magnetic head. D is a manufacturing process diagram showing a conventional method of manufacturing a magnetic head.

FIG. 11 is a manufacturing process diagram illustrating a conventional method of manufacturing a magnetic head. F is a manufacturing process diagram illustrating a conventional method of manufacturing a magnetic head.

FIG. 12 is a manufacturing process diagram illustrating a conventional method of manufacturing a magnetic head.

FIG. 13 is a perspective view for explaining the related art.

FIG. 14 is a side view provided for conventional description.

[Explanation of symbols]

 31 Groove for Inserting Central Core 31a Bottom of Groove 32 Side Core Block 32 Lower Side of C Side Core Block 32, 33 Step 35 Central Core 36 Fused Glass l Length of Step F Height of Step 47 Front Core 48 Back core part 49 Winding 50 Bobbin 51 Double gap type erasing magnetic head

Claims (3)

[Claims] 1. A method of manufacturing a double-gap type magnetic head, comprising a side core sandwiching a magnetic gap on both sides of a central core, wherein a groove portion for inserting the central core is formed in the center, and an extending direction of the groove portion. And a step of forming side core blocks having stepped portions at both ends thereof, and a step of inserting the central core into the groove portions of the side core blocks and joining them with a gap forming material. Method. 2. The magnetic head according to claim 1, wherein the height of the step portion is set to be equal to or less than the height from the lower surface of the side core block to the bottom surface of the groove for inserting the central core. Production method. 3. The length of the step portion in the groove extension direction is 0.
The thickness is set to 1 mm or more.
A method of manufacturing a magnetic head according to 1.