JPH0696415A - Step-up type magnetic head and production of magnetic head - Google Patents

Abstract

PURPOSE:To improve matching with an electric circuit by providing a primary coil wire through an insertion hole formed between a pair of magnetic core half bodies and a transformer part and constituting a magnetic gap between magnetic core half bodies. CONSTITUTION:Large current is passed in the primary coil wire 23 by the effect of the transformer part 1 when a secondary coil wire 15 is energized. A sharp gradient of magnetic fluxes is then formed on the outer side of a magnetic gap G and the prescribed point of a magnetic recording medium is magnetized. Magnetic metallic thin films 21 having a high magnetic permeability and high saturation magnetic flux density are used for the magnetic thin films forming the gap G in such a case. The films 21 constitute an annular magnetic circuit enclosing the insertion hole 20 and the size if the hole 20 is governed by the size of the coil wire 23 but the coil wire 23 is wound one turn only and, therefore, the size of the hole 20 is reduced and the magnetic circuit is miniaturized. As a result, this magnetic head is advantageous for dealing with high frequencies and the easier reading of magnetic information is made possible by the miniaturization of the magnetic circuit. An improvement in efficiency at the time of reproducing is resulted as well.

Description

Detailed Description of the Invention

[0001]

This invention has a small magnetic circuit,
The present invention relates to a step-up type magnetic head capable of excellent matching with an electric circuit and a method of manufacturing a magnetic head.

[0002]

2. Description of the Related Art In recent years, there have been some remarkable improvements in the image quality of home VTRs, but the ferrite type magnetic heads that are widely used in these VTRs have undergone various improvements up to the line near the limit. There is. Therefore, in recent years, efforts have been focused on the development of magnetic heads using new materials having excellent magnetic properties such as sendust and amorphous alloys. However, this type of ferrite type magnetic head also has many problems to be solved in mass production.

FIG. 20 shows an example of the structure of a conventionally known magnetic head. In this magnetic head 1, a pair of magnetic core halves 2 and 2 made of ferrite are butted and joined to each other via a magnetic gap 3, and a coil 6 is wound through a winding window 5 provided at the butted portion, and the whole is wound. This structure is attached to a metal base plate 7. The base plate 7 is provided so as to project from the center of the upper portion of a plate-shaped mounting base 8. The mounting base 8 is incorporated in a rotary cylinder device of a VTR, and the magnetic head 1 is a magnetic recording medium such as a magnetic tape. To face.

Here, for example, a VTR as shown in FIG.
In the case of the magnetic head 1 for use as a bulk head, since the magnetic circuit is extremely miniaturized as a bulk head, there is a problem that the winding work becomes difficult. Further, when a signal is read from the magnetic recording medium by the magnetic head 1, a smaller magnetic circuit is more advantageous in terms of reproduction efficiency. Therefore, it is preferable to make the magnetic circuit as small as possible. In the structure shown, the smaller the magnetic circuit, the more difficult the winding work becomes.

[0005]

Therefore, as a magnetic head structure capable of simplifying such winding work, a coil having only one turn is wound around a winding window near a magnetic gap of a magnetic head made of ferrite. A structure has been announced in which a step-up transformer that is rotated and connected to this is integrated into the side of the magnetic head. The magnetic head having this structure has an advantage that it can easily cope with automation of windings and can form a transformer with a high degree of coupling. Further, since the magnetic head and the transformer are arranged at a close distance, there is an advantage that an increase in inductance and resistance of the magnetic head as a whole can be suppressed. However, even in this type of magnetic head, since the magnetic head itself is made of ferrite, there is a problem in that it is not compatible with a high coercive force medium such as a metal tape.

The present invention has been made in view of the above circumstances, and the transformer section is arranged at a close distance to the magnetic gap to enhance the degree of coupling with the transformer section, and electrical matching with an electric circuit to be connected is easy. And a step-up magnetic head having a novel structure in which winding processing is easy and automation is easy and magnetic recording can be performed with a margin even on a magnetic recording medium having a high coercive force, and manufacturing of the magnetic head. The purpose is to provide a method.

[0007]

In order to solve the above-mentioned problems, the invention according to claim 1 is such that a secondary coil wire is attached to a transformer base to form a transformer section, and a pair of magnetic cores are provided in the transformer section. A magnetic core portion composed of half bodies is joined, an insertion hole is formed between the pair of magnetic core halves, a magnetic gap is formed between the magnetic core halves, and the insertion hole and the transformer are formed. And the primary coil wire is wound around it.

In order to solve the above-mentioned problems, a second aspect of the present invention is that a secondary coil wire is wound around a transformer base made of a magnetic material formed in an annular shape having a winding window in a central portion. A transformer portion is configured, and a pair of magnetic core halves are joined to the transformer portion by forming an insertion hole between the magnetic core halves, and a magnetic gap is formed between the magnetic core halves. , Passing through the winding window and the insertion hole 1
The next coil wire is wound.

According to a third aspect of the present invention, there is provided a magnetic head according to the first or second aspect, in order to solve the above problems.
The primary coil wire, which is mounted by passing through the winding window and the transformer part, is wound by one turn, and the primary coil wire is formed thicker than the secondary coil wire wound around the transformer part. is there.

According to a fourth aspect of the present invention, in order to solve the above problems, in the magnetic head according to the second aspect, the winding window of the transformer portion is formed larger than the insertion hole on the magnetic core half body side. is there.

According to a fifth aspect of the present invention, a groove is formed on one surface of the block, one surface of the block including the groove is covered to form a metal magnetic thin film, and the groove is filled on the metal magnetic thin film in the groove. A welded glass portion is formed, then a gap layer and a second metal magnetic thin film are formed on the metal magnetic thin film, a second block is glass-welded on the second metal magnetic thin film, and then the groove portion is formed. A plurality of magnetic heads are obtained by melting and removing only the welded glass portion inside and then cutting from the pair of welded blocks.

[0012]

Since the primary coil wire is provided by passing through the insertion hole formed between the pair of magnetic core halves and the transformer section to form the magnetic gap between the magnetic core halves, the transformer section is provided with the magnetic gap. A step-up type magnetic head arranged in the vicinity is constructed.

If an insertion hole for forming a magnetic gap is provided in the magnetic core half body and the primary coil passing through this has only one turn, the insertion hole is smaller than the winding window of the conventional magnetic head. Therefore, the magnetic circuit becomes smaller, and the primary coil wire is made thicker than the secondary coil wire, so that a larger current than the secondary coil wire can flow through the primary coil wire. Therefore, the magnetic head including the step-up transformer is configured, and matching can be easily performed when connecting to the electric circuit. Further, since a large amount of current can be passed through the thick primary coil wire, the step-up action of the transformer section can be achieved and
The heat generation in the secondary coil can be suppressed and the heat generation can be reduced.

On the other hand, by forming the insertion hole through which the primary coil wire is inserted smaller than the winding window through which the secondary coil wire is inserted, the magnetic circuit can be downsized as described above and the winding Even if the window is made large, it does not adversely affect the miniaturization of the magnetic circuit, so that the winding window can be made large, which facilitates the work of winding the secondary coil wire and at the same time makes the primary coil wire. Since the coil is wound around the insertion hole for only one turn, the winding work can be easily performed. Therefore, the automation of winding work becomes easy.

Further, when a magnetic head is manufactured by the method of the present invention, two metal magnetic thin films and a gap layer are formed in layers before the blocks are joined to each other, so that the positioning for forming the magnetic gap is performed. It will be done at the time of the film. That is, when the gap layer and the second metal magnetic thin film are stacked on the metal magnetic thin film, the films for forming the magnetic gap are stacked, so that the bonding state of both blocks facing each other across the magnetic gap may be slightly different. Even if it shifts, it does not lead to the position shift of the laminated film in the magnetic gap portion. Therefore, the magnetic gap can be formed with the same precision as that at the time of film formation, whereby the gap can be formed with high precision.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of a magnetic head according to the present invention. The magnetic head 10 of this embodiment is
The magnetic head is used by being incorporated in a VTR like the conventional magnetic head shown in FIG. 20, and is mounted on a metal base plate 11 as shown in FIG. This magnetic head 10
Is composed of a transformer section 12 and a magnetic core section 13. The transformer section 12 is mainly composed of a transformer core 14 made of a magnetic material having a rectangular side surface and a secondary coil wire 15 having an insulating layer and wound around the transformer core 14. A winding window 16 is formed in each of the winding windows 16, and the secondary coil wire 1 is provided on both sides of the winding window 16.
5 and 15 are wound respectively. The transformer core 14 is fixed to the base plate 11 at its lower portion. The transformer core 14 is made of a normal magnetic material such as Mn-Zn ferrite for a magnetic head.

A magnetic core portion 13 is fixed to an upper portion of the transformer core 14, and the magnetic core portion 13 includes a pair of magnetic core halves 17 made of a non-magnetic material and a gap between the side portions. The two are abutted to each other via the layer 18 and bonded by glass welding, and the magnetic core halves 17 and 1 of FIG.
A medium facing surface 19 is formed on the upper surface side of 7. As shown in an enlarged view in FIG. 2, a hexagonal side surface through hole 20 is formed in the joint portion of the magnetic core halves 17 and 17, and the joined side surfaces of the magnetic core halves 17 and 17 are connected to each other. The metal magnetic thin films 21 are laminated so as to cover the metal magnetic thin films 21 and 21.
Surrounds the insertion hole 20, and further the metal magnetic thin film 2
The magnetic gaps G are formed by exposing 1 and 21 on the medium facing surface 19. The metal magnetic thin film 21 includes a plurality of metal thin films 21a as shown in FIG.
It has a laminated structure in which the layers are laminated via 1b. In the above structure, the magnetic core half body 17 is preferably made of a non-magnetic material rather than a magnetic material in view of cost and workability, but of course, the magnetic core half body 17 is made of a magnetic material. However, the insertion hole 20 may have a shape other than the hexagonal shape, and the metal magnetic thin film 21 may have a single layer structure. Further, reference numeral 22 in FIG. 2 is a fused glass layer in which the magnetic core halves 17, 17 are joined.

The non-magnetic material forming the magnetic core half body 17 is made of ceramic such as Al ₂ O ₃ or SrTiO ₃ . The metal magnetic thin film 21 is a sendust thin film of Fe-Al-Si alloy having a saturation magnetic flux density of 10,000 G or more, a soft magnetic alloy thin film of Fe-Ta-C system, Fe-Al-Ta-C system, etc., an amorphous alloy thin film. Etc., is composed of a soft magnetic material having a saturation magnetic flux density higher than that of a commonly used ferrite. The gap layer 18 is made of Si.
It is made of a non-magnetic material such as O ₂ , Al ₂ O ₃ and CrSiO ₂ .

Further, a primary coil wire 23 wound around the insertion hole 20 and the winding window 16 is provided. The primary coil wire 23 is composed of a conductor portion 24 and an insulating layer 25 covering the peripheral surface thereof, and the conductor portion 24 has a diameter larger than that of the conductor portion of the secondary coil wire 15. The conductor portion 24 is made of a conductive material such as copper and has a diameter of 70 to 100 μm.
The insulating layer 25 may be made of an insulating material such as polyurethane or nylon and has a thickness of 5 to 10
A material having a size of about μm can be used. The conductor portion 24
Is made larger in diameter than the secondary coil wire 15 so that a larger current than the secondary coil wire 15 can flow through the primary coil wire 23 when the transformer section 12 is operated as described later. This is to reduce the amount of heat generated in the primary coil wire 23.

The magnetic head 10 having the above-described structure is used to perform magnetic recording and reproduction on a magnetic recording medium such as a magnetic tape as in the conventional magnetic head. To this end, when the secondary coil wires 15 and 15 are energized, a large current can be made to flow in the primary coil wire 23 by the action of the transformer section 1, and thereby a steep magnetic flux gradient is generated outside the magnetic gap G. Since it can be formed, it suffices to magnetize a desired portion of the magnetic recording medium. in this case,
Since the magnetic thin films forming the magnetic gap G are the metal magnetic thin films 21 having a high magnetic permeability and a high saturation magnetic flux density, magnetic recording can be performed with a margin even in a magnetic recording medium having a magnetic layer having a high coercive force. Therefore, it is possible to cope with the high density of magnetic recording which cannot be handled by an ordinary ferrite head.

Further, the metal magnetic thin films 21 and 21 are provided with the insertion holes 2
An annular magnetic circuit that surrounds 0 is configured. Here, the size of the insertion hole 20 is governed by the outer diameter of the primary coil wire 23. However, since the primary coil wire 23 is wound only one turn, the winding provided in the conventional magnetic head is used. The insertion hole 20 is smaller than the wire window. As a result, the magnetic circuit around the insertion hole 20 can also be downsized, which is advantageous over the conventional magnetic head in that it can handle higher frequencies, and the downsizing of the magnetic circuit makes it easier to read the magnetic information recorded on the magnetic recording medium. , The efficiency at the time of reproduction is also improved. Furthermore,
In the above structure, since the transformer core 14 and the winding window 16 for winding the secondary coil wire 15 are independent of the size of the magnetic circuit, they can be formed larger than conventional ones, which facilitates winding work. Therefore, the winding work can be easily automated.

On the other hand, the transformer core 14 and the secondary coil wire 1
Since the transformer section 12 composed of 5 is provided close to the magnetic gap G, it is convenient for matching with the electric circuit to which the magnetic head 10 is connected in the electric circuit of the VTR in which the magnetic head 10 is provided. . Therefore, if the transformer 12 is designed with high efficiency, the magnetic circuit of the magnetic head 10 can be downsized. Further, the magnetic circuit is replaced by the metal magnetic thin film 21,
Since it can be composed of 21 single materials, a magnetic head with high output and low noise can be obtained.

Next, the primary coil wire 23 and the secondary coil wire 15
When magnetic recording is performed by energizing the primary coil wire 23 for one turn and the secondary coil wire 15 for 20 turns, the action of the transformer section 12 causes the primary coil wire 23 to become the secondary coil wire 15 Since a current 20 times as much as the flowing current flows, it is necessary to design the primary coil wire 23 to have a diameter larger than that of the secondary coil wire 15 to reduce heat generation. As a result, it is possible to reduce heat generation in the primary coil wire 23 during magnetic recording and to prevent a thermal adverse effect on the metal magnetic thin film 21. Therefore, when the diameter of the secondary coil wire 15 is set to, for example, about 30 μm, the primary coil wire 23
The diameter may be set to several times, for example, 70 to 100 μm.

Next, an example of a method of manufacturing the magnetic head according to the present invention will be described. In order to manufacture a magnetic head, first, a plate-shaped block 30 shown in FIG. 3, which is made of a non-magnetic material such as crystallized glass or ceramics and has a plane rectangular shape, is used. Grinding is performed using a grinding stone or the like to form a triangular groove portion 31 as shown in FIG. Next, as shown in FIG. 5, a plurality of metal magnetic thin films 32 are alternately laminated together with an interlayer insulating layer on the entire upper surface of the block 30 by a film forming method such as sputtering. Next, the welding glass 33 is poured into the groove portion 31 as shown in FIG. 6, and the welding glass that overflows from the groove portion 31 and is solidified is removed by polishing such as lapping.
The welded glass portion 34 that fills the groove portion 31 as shown in FIG.
And the metal magnetic thin film 3 on the plane portion on the block 30 is formed.
2 and the upper surface of the fused glass portion 34 are formed flush with each other.

Next, a gap film for forming a gap layer is formed on these, and a metal magnetic thin film 36 made of the same material as the metal magnetic thin film 32 is further formed as shown in FIG. Subsequently, as shown in FIG. 9, track grinding is performed diagonally along the upper left edge of the block 30 using a grindstone or the like, and the metal magnetic thin films 36 and 32, the welded glass part 34, and a part of the block 30 are spaced by a predetermined distance. A plurality of recesses 37 that are intermittently continuous are formed at intervals. The concave portion 37 formed here is formed so as to obliquely penetrate the metal magnetic thin films 36 and 32 and the upper edge portion of the block 30 to reach the fused glass portion 34.

Next, the block 30 is erected from the state shown in FIG. 9 to the state shown in FIG. 10, and a block 40 made of the same material as the block 30 is joined to the opposite side. Then, the whole is heated to melt the fused glass portion 34. Then, the melted fused glass flows out from the groove portion 31 side of the block 30 through the plurality of concave portions 37, and the groove portion 31.
An insertion hole 42 is formed in the. If the heating temperature is lowered before all the glass flowing out from the groove portion 31 side has flowed out, a part of the welded glass remains in the recess 37, so that the blocks 30 and 40 can be glass-welded. In this step, after all the welding glass has been discharged from the groove 31, another welding glass may be poured into the groove 31 and the block 30 and the block 40 may be joined by the newly poured welding glass. Further, other means may be used to adjust the amount of the welding glass flowing out from the groove portion 31 side, that is, the insertion hole 42 is formed, and at the same time, the welding glass is placed in the groove portion 31 to the extent that the block 30 and the block 40 can be joined. Just leave it.

The joining state of the blocks 30 and 40 is shown in FIG.
Shown in 1. From this state, using a grindstone, as shown by the two-dot chain line in FIG. 11, by cutting and polishing,
The magnetic core part 43 shown in FIG. 12 can be obtained. The magnetic core portion 43 has substantially the same structure as the magnetic core portion 12 of the magnetic head 10 shown in FIG. That is, the magnetic core portion 43 is formed by joining a pair of magnetic core halves 47 made of a non-magnetic material to each other through a gap layer between their side portions and joining them together by glass welding. A medium facing surface 49 is provided on the upper surface side of 47.
Are formed. An insertion hole 42 is formed in the joint portion of the magnetic core halves 47, 47, and each magnetic core half 4 is
Metal magnetic thin film 5 so as to cover the joined side surfaces of 7, 47.
1 is laminated, and the metal magnetic thin films 51, 51 are inserted into the insertion holes 4
A magnetic gap G is formed so as to surround the circumference of 2 and expose the metal magnetic thin films 51, 51 to the medium facing surface 49.
It should be noted that what is denoted by reference numeral 52 in FIG.
It is a fused glass layer in which Nos. 7 and 47 are joined. Further, in the magnetic core portion 43 of this example, the medium facing surface 49 is cut and finely processed.

According to the above-described manufacturing method, the welded glass layer 52 remains thinly on the entire inner surface of the insertion hole 42 as shown in FIG. 12, and the remaining welded glass layer 52 is formed of the metal magnetic thin film 51. Acts as a protective film. That is, when the primary coil wire is inserted into the insertion hole 42 to form a magnetic head, the metal magnetic thin film 51 existing on the inner surface side of the insertion hole 42.
Is likely to be rubbed and damaged by the primary coil wire, but since the welded glass layer 52 protects the damage, it is possible to prevent deterioration of the magnetic characteristics of the metal magnetic thin film 51. Further, even if the insulating coating of the primary coil wire is damaged, the welded glass layer 52 becomes an insulating layer, so that the insulation failure of the primary coil wire can be prevented.

According to the method described above, the magnetic core portion 43
Therefore, the magnetic core portion 43 was attached to the transformer portion made of a magnetic material by a bonding method such as adhesion, and the primary coil wire was laid between the insertion hole 42 of the magnetic core portion 43 and the winding window of the transformer portion. The target magnetic head can be manufactured by winding one turn and joining the ends of the primary coil wire. The ends of the wound primary coil wires may be joined by soldering, twisting, or bonding with a conductive adhesive. If the workability of joining the primary coil wire is taken into consideration, the primary coil wire may be extended to a portion a little away from the magnetic gap G, for example, the attachment base 8 and joined there to form a coil.

When the magnetic core portion 43 is manufactured by the method described above, the blocks 30 and 4 are formed as shown in FIG.
This means that the positioning for forming the magnetic gap G was performed before the 0 was joined. That is, FIG.
As shown in FIG. 5, when the metal magnetic thin film 36 is laminated on the metal magnetic thin film 32, the films for forming the magnetic gap G are laminated, so that the blocks 30 and 40 facing each other across the magnetic gap G are joined together. Does not lead to positional deviation of the laminated film in the magnetic gap G portion. Therefore, the accuracy at the time of forming the magnetic gap G can be the same as that at the time of film formation, and thus the accurate gap can be formed.

On the other hand, conventionally, in a MIG (Metal In Gap) type magnetic head including a ferrite head and a metal magnetic thin film, the magnetic head was manufactured as follows. First, a pair of ferrite magnetic core halves each having a metal magnetic thin film formed thereon were prepared, and both of them were welded with glass with a gap layer interposed therebetween.
Therefore, in the case of this manufacturing method, if the magnetic core halves are not accurately aligned at the time of joining, there is a problem that the dimensional accuracy of the gap portion decreases and the magnetic characteristics are adversely affected. On the other hand, if the above-described manufacturing method is adopted, a gap is formed during film formation, so that a precise gap can be formed in accordance with the accuracy at the time of film formation.

Next, another method for manufacturing the magnetic core portion will be described. A method similar to the method described above based on FIGS. 3 to 8 is carried out to form the welded glass portion 34 and the metal magnetic thin films 32 and 36 on the block 30 as shown in FIG. Next, the block 30 is erected from the state shown in FIG. 13 to the state shown in FIG. 14, a block 40 made of the same material as the block 30 is abutted on the opposite side, and the abutting surfaces are joined by glass welding. Then, the whole is heated to melt the fused glass portion 34. Next, almost all of the melted fused glass is made to flow out from the open end of the groove 31 of the block 30, and the insertion hole 4 is inserted into the groove 31.
Form 2. Here, the glass flowing out of the groove portion 31 between the block 30 and the block 40 may be left in the corner portion of the groove portion 31 to some extent, and the block 30 and the block 40 are joined by the welded glass of their abutting surfaces.

This joined state is shown in FIG. From this state, the magnetic core portion 63 shown in FIG. 16 can be obtained by performing cutting out and polishing as shown by the chain double-dashed line in FIG. 15 using a grindstone. The magnetic core portion 63 has substantially the same structure as the magnetic core portion 43 shown in FIG. That is, the magnetic core portion 63 is formed by joining a pair of magnetic core halves 67 made of a non-magnetic material to each other through a gap layer between their side portions and joining them together by glass welding. A medium facing surface 69 is formed on the upper surface side of 67. The magnetic core half 6
An insertion hole 62 is formed in the joint portion of 7, 67, a metal magnetic thin film 71 is laminated so as to cover the joined side surfaces of the magnetic core halves 67, 67, and the metal magnetic thin film 71, 71 is inserted therethrough. Surrounding the perimeter of the hole 62, a metal magnetic thin film 71,
The magnetic gap G is formed by exposing 71 to the medium facing surface 69. In addition, what is denoted by reference numeral 72 in FIG. 16 is a fused glass layer in which the magnetic core halves 67, 67 are joined.
The metal magnetic thin film 71 of the magnetic core portion 63 shown in FIG.
The enlarged structure of the gap portion is shown in FIG. As shown in FIG. 17, the metal magnetic thin film 71 has a layered structure in which metal magnetic thin films and insulating layers are alternately laminated.

By the method described above, the magnetic core portion 63
Therefore, the magnetic core portion 63 is attached to the transformer portion made of a magnetic material by a bonding method such as adhesion, and the primary coil wire is connected between the insertion hole 62 of the magnetic core portion 63 and the winding window of the transformer portion. If wound, the desired magnetic head can be manufactured.

18 and 19 show the structure of another embodiment of the magnetic head according to the present invention. The magnetic head 80 of this embodiment includes a transformer portion 82 and a magnetic core portion 83, but the transformer portion 82 is different from the structure of the previous embodiment. The magnetic core portion 83 has the same configuration as that of the previous embodiment, and the magnetic core portion 83 includes a pair of magnetic core halves 87 made of a nonmagnetic material with a gap layer between their side portions. The two are abutted to each other via glass and bonded by glass welding, and a medium facing surface 89 is formed on the upper surface side of the magnetic core halves 87. An insertion hole 90 is formed in the joining portion of the magnetic core halves 87, 87, and a metal magnetic thin film 91 is laminated so as to cover the joined side surfaces of the magnetic core halves 87, 87.
1 and 91 surround the insertion hole 90, and the magnetic metal thin films 91 and 91 are exposed to the medium facing surface 89 to form a magnetic gap G. The metal magnetic thin film 91 has a laminated structure in which a plurality of metal thin films are laminated via an interlayer insulating layer.

Next, the transformer section 82 comprises a transformer base 84 made of a non-magnetic material and a transformer body 85 attached to the side of the transformer base 84. This transformer body 85 has a coil mounting groove 93 inside.
And a secondary coil wire 95 inserted in a coil mounting groove of the transformer core 94 made of a magnetic material.
And a primary coil wire 96. And the above 1
A part of the secondary coil wire 96 extends from the coil mounting groove 93 and is inserted into the insertion hole 90 of the magnetic core portion 83 through the through hole 84a formed in the transformer base 84, and the secondary coil wire 95 is formed.
Is partly taken out from the coil mounting groove 93 and connected to the electric circuit of the VTR.

Since the transformer main body 85 is also provided by the above structure, the same effect as that of the previous embodiment can be obtained. Moreover, if the structure of this example is adopted,
The transformer base 84 can be made of a non-magnetic material instead of a magnetic material.

[0038]

As described above, according to the present invention, the primary coil wire is provided by passing through the insertion hole formed between the joint portions of the pair of magnetic core halves and the transformer portion, Since the magnetic gap is formed by the magnetic core halves, it is possible to form a step-up type magnetic head in which the transformer portion is arranged near the magnetic gap.

Next, if an insertion hole for forming a magnetic gap is provided in the magnetic core half body and the primary coil passing through this is made up of only one turn, the insertion hole is formed in the winding window of the conventional magnetic head. Since it can be made smaller, the magnetic circuit can be made smaller, the reproduction efficiency can be improved, and the primary coil wire can be made thicker than the secondary coil wire so that the primary coil wire is
It becomes possible to pass more current than the next coil wire. Therefore, the magnetic head having the step-up transformer is configured, and it is easy to match the magnetic head when connecting to the electric circuit. In addition, since a large amount of current can be passed through the thick primary coil wire, the step-up action of the transformer portion can be achieved, and the heat generation in the primary coil can be suppressed to reduce heat generation.

On the other hand, by forming the insertion hole through which the primary coil wire is inserted smaller than the winding window through which the secondary coil wire is inserted, the magnetic circuit can be downsized as described above and the winding Even if the window is made large, it does not adversely affect the miniaturization of the magnetic circuit, so that the winding window can be made large, which facilitates the work of winding the secondary coil wire and at the same time makes the primary coil wire. Since the coil is wound around the insertion hole for only one turn, the winding work can be easily performed. Therefore, the winding work can be easily automated and the load on the automatic machine is reduced.

Further, when the magnetic head is manufactured by the method of the present invention, two metal magnetic thin films and the gap layer are formed in layers before the blocks are joined to each other, so that the positioning for forming the magnetic gap is performed. It will be done at the time of the film. That is, when the gap layer and the second metal magnetic thin film are stacked on the metal magnetic thin film, the films for forming the magnetic gap are stacked, so that the bonding state of both blocks facing each other across the magnetic gap may be slightly different. Even if it shifts, it does not lead to the position shift of the laminated film in the magnetic gap portion. Therefore, the magnetic gap can be formed with the same precision as that at the time of film formation, whereby the gap can be formed with high precision.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of a magnetic head according to the present invention.

FIG. 2 is an enlarged cross-sectional view showing a main part of the magnetic head shown in FIG.

FIG. 3 is a perspective view showing a block used in manufacturing the magnetic head according to the present invention.

FIG. 4 is a perspective view showing a state in which a groove is formed in the block shown in FIG.

5 is a perspective view showing a state in which a magnetic thin film is formed on the block shown in FIG.

6 is a perspective view showing a state in which a fused glass is poured into a groove portion of the block shown in FIG.

FIG. 7 is a perspective view showing a state in which an unnecessary portion of the upper portion of the fused glass shown in FIG. 6 is scraped off.

FIG. 8 is a perspective view showing a state in which a metal magnetic thin film is further formed on the fused glass and the metal magnetic thin film shown in FIG.

9 is a perspective view showing a state in which a concave portion is formed by polishing the upper edge portion of the block shown in FIG.

10 is a perspective view showing a state in which another block is joined to the block shown in FIG.

FIG. 11 is a perspective view for explaining a case where a magnetic core portion is cut out from two joined blocks.

FIG. 12 is a perspective view showing a magnetic core portion cut out from the block shown in FIG. 11.

FIG. 13 shows another method for obtaining the magnetic head according to the present invention, and is a perspective view showing a state in which another metal magnetic thin film is formed on the fused glass and the metal magnetic thin film. .

14 is a perspective view showing a state in which another block is joined to the block shown in FIG.

FIG. 15 is a perspective view for explaining a case where a magnetic core portion is cut out from two joined blocks.

16 is a perspective view showing a magnetic core portion cut out from the block shown in FIG.

17 is an enlarged view showing a metal magnetic film portion of the magnetic core portion shown in FIG.

FIG. 18 is a side view showing another example of the magnetic head according to the present invention.

19 is an exploded perspective view of the transformer portion of the magnetic head shown in FIG.

FIG. 20 is a front view showing a mounting state of a conventional magnetic head on a base plate.

[Explanation of symbols]

G magnetic gap, 10, 80,
Magnetic head, 11 base plate,
12, 82, transformer part, 13, 4
3, 63, magnetic core part, 14, 94,
Transformer core, 15, 95 secondary coil, 1
6 winding windows, 17, 47, 67, 87,
Magnetic core halves, 19, 49, 89,
Medium facing surface, 20, 42, 90,
Insertion holes, 21, 51, 71, 91,
Metal magnetic thin film, 23, 96,
Primary coil, 30, 40,
Block 31,
Groove, 32, 36,
Metal magnetic thin film, 34,
Fused glass part,

Claims (5)

[Claims] 1. A secondary coil wire is attached to a transformer base to form a transformer section, and a magnetic core section consisting of a pair of magnetic core halves is joined to the transformer section, and the pair of magnetic core halves are mutually connected. An insertion hole is formed between the magnetic core halves, a magnetic gap is formed between the magnetic core halves, and a primary coil wire is wound through the insertion hole and the transformer portion. Step up type magnetic head. 2. A transformer base is formed by winding a secondary coil wire around a transformer base made of a magnetic material and formed in an annular shape having a winding window in the center, and a pair of magnetic members is formed on the transformer base. The core halves are joined by forming an insertion hole between the magnetic core halves, a magnetic gap is formed between the magnetic core halves, and the core half passes through the winding window and the insertion hole. And a primary coil wire is wound around the step-up type magnetic head. 3. The magnetic head according to claim 1 or 2, wherein the primary coil wire which is mounted by passing through the winding window and the transformer part is wound by one turn, and the primary coil wire is mounted on the transformer part. A step-up type magnetic head, wherein the step-up type magnetic head is formed thicker than the formed secondary coil wire. 4. The step-up type magnetic head according to claim 2, wherein the winding window of the transformer section is formed larger than the insertion hole of the magnetic core half body. 5. A groove portion is formed on one surface of the block, a metal magnetic thin film is formed by covering one surface of the block including the groove portion, and a fused glass portion for filling the groove portion is formed on the metal magnetic thin film in the groove portion. After that, a gap layer and a second metal magnetic thin film are formed on the metal magnetic thin film, a second block is glass-welded on the second metal magnetic thin film, and thereafter only the welded glass portion in the groove is formed. A method for manufacturing a magnetic head, characterized in that a plurality of magnetic heads are obtained by melting and removing the magnetic powder, and then cutting the pair of the fused blocks.