JP2000298808A - Magnetic head and fabrication method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic head and a fabrication method thereof capable of effectively suppressing fog to be caused by an influence of an external magnetic field driven from an adjacent recording head or the like. SOLUTION: This magnetic head includes a magnetic core made of a magnetic material, in which a pair of core halves 11, 12 are abutted to each other, wherein a winding groove 11a is provided at an abutting surface of one half 11 of the core halves, so that a gap 13 is formed at one end on the side of a sliding surface 10a and at the same time a winding window is formed below the gap. The magnetic head further includes a first coil 14 that is wound around the winding groove 11a and an outer side surface of said one of the core half pieces. The other core half piece 12 is provided with an anti-fogging groove 16 that is formed at the abutting surface thereof to face at least the vicinity of an end of the winding groove of the opposing core half.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recording data on a magnetic recording medium such as a magnetic tape for recording and reproducing data on a video tape recorder (VTR), a digital audio tape recorder (DAT) or a computer. The present invention relates to a magnetic head for reproducing and / or a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, such a magnetic head is configured as shown in FIG. In FIG. 9, the magnetic head 1 includes a magnetic core composed of two core halves 2 and 3 joined to each other.

The core halves 2 and 3 are each made of a magnetic material such as ferrite, and form a so-called gap near at least the surface 1a (contact surface with the magnetic recording medium) of the joining surfaces to be joined to each other. A surface is provided. A gap 4 is formed between the core halves 2 and 3. Also, one core half 2 is
A winding groove 2a for receiving a winding wound as a coil and regulating the depth Dp of the gap 4 is provided on the joining surface.
And the outer surfaces of the core halves 2 and 3 include:
The winding guide grooves 2b and 3b are formed respectively. Then, through the winding window formed by the winding groove 2a and through the winding guide grooves 2b,
Coils 5 and 6 are wound around 3b, respectively.

According to the magnetic head 1 configured as described above, at the time of recording, for example, a magnetic tape (not shown) slides along the sliding surface 1a of the magnetic head 1 in the direction of the arrow T, and the magnetic tape from the outside. When a drive current is introduced into the coils 5 and 6 wound around the core halves 2 and 3 of the head 1, a magnetic field corresponding to the drive current is generated in the coils 5 and 6. The magnetic field generated in the coils 5 and 6 circulates around the winding window formed by the winding groove 2a of the core half 2 as a magnetic path, and passes through the gap 4, thereby forming a magnetic tape. On the other hand, magnetic recording of desired data is performed. At the time of reproduction, a magnetic field circulating through the core halves 2 and 3 is generated from the gap 4 based on a magnetic signal recorded on the sliding magnetic tape, and a signal current is applied to the coils 5 and 6 based on the magnetic field. Occurs. Then, the signal current generated in the coils 5 and 6 is taken out to the outside and appropriately processed, whereby the data recorded on the magnetic tape is reproduced.

[0005]

In recent years, a higher recording density has been demanded in order to increase the image quality of video signals, increase the recording capacity, or increase the information transfer speed. There is also a demand for a magnetic recording device for recording video, information, or the like, which is smaller and lighter in terms of portability or for incorporation into a computer. Along with this, a magnetic head mounted on a rotating drum is required to have a high output, and the number of mounted magnetic heads tends to increase. Further, in a commercial VTR or a data recording apparatus, a reproduction monitor is arranged immediately after a recording head and a recording / reproducing simultaneous monitor is performed in order to confirm whether a recording signal is recorded correctly, and thereby, recording data is recorded. I try to increase reliability.

By the way, when the number of magnetic heads mounted on the rotary drum increases for such a reason, the distance between the recording head and the reproducing head becomes narrow, and the magnetic field jumping from the recording head to the reproducing head increases. The so-called "fogging" phenomenon, which affects the reproduced signal from the reproducing head, becomes a problem. For this reason, conventionally, in order to reduce the current induced by the magnetic field jumping from the recording head, the number of coils wound around the opposing magnetic core halves is made equal, or the core volumes of the magnetic core halves differ greatly. In such cases, countermeasures such as increasing the number of turns of the coil wound around the magnetic core half having the smaller core volume are taken. For example, in the magnetic head 1 shown in FIG. 9, the distance L1 between the winding groove 2a and the winding guide groove 2b of the core half 2, the gap opposing surface of the core half 3 and the winding guide groove 3
Since the distance L2 between the coils 5 and b is different, the coil 5
By making the number of turns larger than that of the coil 6, fogging is suppressed.

As another countermeasure against fogging, when the fogging source is an adjacent recording head, the number of turns of the coil of the core half on the recording head side, for example, the core half 2, is changed to the opposite side of the recording head. By reducing the number of turns of the core half 3, the fogging is suppressed. However, as the recording density has been increased as described above, the recording signal has been increased in frequency, and the distance between the recording head and the reproducing head has been shortened. Even if it can be reduced, the rate of improvement is limited.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide a magnetic head and a method of manufacturing the same, which are capable of effectively suppressing fogging due to an external magnetic field such as an adjacent recording head. I have.

[0009]

According to the first aspect of the present invention, a pair of core halves are joined and abutted to each other, and one end of a sliding surface to be brought into contact with a magnetic recording medium is provided at one end. A magnetic core made of a magnetic material having a winding groove on a mating surface of at least one core half so as to form a gap and form a winding window below the gap,
The first core half includes a winding groove and a first coil wound around an outer surface, and the other core half has a winding surface of one core half on its abutting surface. This is achieved by a magnetic head having a fogging countermeasure groove formed facing at least near the edge of the groove on the gap side.

[0010] Further, according to the present invention, a first step of forming a winding groove or an anti-fogging groove at the joint surface of the two core halves, respectively, A second step of forming the magnetic core block by joining the bodies to each other by glass-filling the winding windows formed by the winding grooves by facing the bodies with the gap material interposed therebetween; A third step of polishing a sliding surface having a predetermined curvature by polishing an end face of the magnetic core block, and a fourth step of cutting a magnetic core block to cut individual magnetic heads by chip thickness cutting and back cutting. And a fifth step of winding a coil around at least one core half through a winding window.

According to the first or seventh aspect of the present invention, a fogging prevention groove is formed on the butting surface of the other core half opposite to the winding groove formed on the butting surface of one core half. Therefore, for example, even when the recording head is disposed close to the recording head, the influence of the magnetic field jumping from the recording head is reduced, and the occurrence of fog is suppressed.

According to the second aspect of the invention, when the fogging countermeasure groove of the other core half has a depth larger than the winding groove of the one core half, the fogging prevention groove is formed by the winding groove. The depth works effectively, and the depth of the fogging prevention groove does not affect the magnetic field passing through the gap.

According to the third aspect of the present invention, when the depth difference between the depth of the fogging countermeasure groove and the depth of the winding groove is 30 to 40 μm, the effect of suppressing fog can be appropriately obtained.

According to the configuration of the fourth aspect, the second coil is wound around the fog preventing groove and the outer surface of the other half of the core, and the number of turns of the coil on the recording head side is reduced. If the number of turns is smaller than the number of turns of the coil on the opposite side, the fog is suppressed by the balance of the number of turns even if the recording head is disposed immediately before the present magnetic head.

According to the fifth aspect of the present invention, when the edge on the gap side of the fogging prevention groove is formed so as to extend obliquely toward the gap side toward the abutting surface, the fogging prevention groove is formed. Since the occurrence of chipping is suppressed during the processing of the groove, the yield of the magnetic head is improved, and the manufacturing cost is reduced. .

According to a sixth aspect of the present invention, when a metal magnetic film and a gap film are formed on the joint surface of the core half, the track width regulating groove and the surface of the winding window, the magnetic head can be used. It is configured as a so-called metal-in-gap head, and also in this case, the occurrence of fog is suppressed.

According to the configuration of claim 7, in addition to the above-described operation, the magnetic head is manufactured with almost no change in the conventional manufacturing method of the magnetic head, so that it is not necessary to facilitate special equipment. Also, the cost does not increase.

According to the eighth aspect of the present invention, when the anti-fogging groove is formed by a grinding wheel for machining a winding groove, it is not necessary to prepare a grinding stone for machining a fogging groove. Fogging grooves are machined by the grinding wheel, so that the present magnetic head can be manufactured using the conventional magnetic head manufacturing process and equipment as they are, thereby reducing equipment costs and manufacturing costs. become.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. still,
Since the embodiments described below are preferred specific examples of the present invention, various technically preferred limitations are added.
The scope of the present invention is not limited to these embodiments unless otherwise specified in the following description.

FIG. 1 shows a first embodiment of a magnetic head according to the present invention. In FIG. 1, a magnetic head 10
Includes a magnetic core consisting of two core halves 11 and 12 joined together.

The core halves 11, 12 are, as described later,
Each is made of the same magnetic material such as ferrite. At least the surface 10a (contact surface with the magnetic recording medium) of the bonding surfaces of the core halves 11, 12 to be bonded to each other is a so-called gap forming surface.
A gap 13 is formed between the core halves 11 and 12 on this surface. Also, one core half 11
Has a winding groove 11a on its joint surface for receiving a winding wound as a coil and for regulating the depth Dp of the gap 13, and has an outer surface of each of the core halves 11, 12. Have winding guide grooves 11b and 12b, respectively. Then, through the winding window formed by the winding groove 11a and through at least one of the core halves 11 or 12, in the illustrated case, both core halves 11,
12, coils 14 and 15 are wound respectively.

The above configuration is substantially the same as that of the conventional magnetic head 1 shown in FIG. 9, but in the magnetic head 10 according to the present embodiment, the winding surface is It has a groove formed facing the groove 11a. This groove is the fogging prevention groove 16. The fogging countermeasure groove 16 has a greater depth Dp2 than the winding groove 11a, and has a depth difference Mr with respect to the depth Dp of the winding groove 11a. Here, the fogging prevention groove 16 has a length (in the vertical direction in the drawing) of 200.
It is sufficient if the length is not less than μm, but if it is too long, there is a risk of disconnection or dielectric breakdown of the coil due to an edge portion or the like. Therefore, it is desirably substantially the same length as the winding groove 11a as shown in the figure. The depth (length in the left-right direction in the figure) of the fogging countermeasure groove 16 is preferably in the range of about 30 μm to 200 μm for the signal.

The magnetic head 10 having such a configuration is manufactured as described below at the time of manufacturing. First, Figure 2
As shown in (A), a pair of plate-like substrates 20 and 30 made of, for example, ferrite are prepared. In the case of the drawing, since each of the substrates 20 and 30 has the same shape, only one of them is shown. The substrates 20 and 30 have upper surfaces (main surfaces) 20 thereof.
Track width regulating grooves 21 and 31 are formed such that a ferrite cross section having a track width Tw remains in the width direction of a and 30a (see FIG. 2B). Subsequently, one substrate 20
As shown in FIG. 2C, a winding groove 22 (11a) for receiving a coil winding and regulating a gap depth Dp is formed along the longitudinal direction of the main surface 20a. . On the other hand, as shown in FIG. 2D, the other substrate 30 has the above-described fogging prevention groove 32 (16) formed along the longitudinal direction of the main surface 30a.

The pair of substrates 20 and 3 configured as described above
As shown in FIG. 3 (A), as shown in FIG. 3 (A), two core half blocks are overlapped via a gap spacer so that their main surfaces are in contact with each other. Filled in the grooves 21, 31,
The two substrates 20, 30 are joined together. Thereafter, as shown in FIG. 3B, the surface in contact with the magnetic tape is cylindrically ground to form the sliding surface 24 (10a), and the magnetic core block 25 is formed.

Finally, the magnetic head 10 shown in FIG. 1 is completed by cutting the chip thickness by, for example, slicing for each track width regulating groove 31 in the longitudinal direction so as to have a predetermined chip thickness.

The magnetic head 10 according to the present embodiment is configured as described above. At the time of recording, a magnetic tape (not shown) slides along the sliding surface 10a of the magnetic head 10 in the direction T in FIG. I do. Then, the magnetic head 1 is externally provided.
Coil 14, 15 wound around core halves 11, 12
, A magnetic field corresponding to the drive current is generated in the coils 14 and 15. The magnetic field generated in the coils 14 and 15 is applied to the core half 1
By circulating as a magnetic path around the winding window formed by the first and second winding grooves 11a and passing through the gap 13, magnetic recording of desired data is performed on the magnetic tape.

At the time of reproduction, a magnetic field circulating through the core halves 11, 12 is generated from the gap 13 based on a magnetic signal recorded on the sliding magnetic tape, and the coils 14, 15 are generated based on the magnetic field. , A signal current is generated. Then, the signal current generated in the coils 14 and 15 is taken out to the outside and appropriately processed, so that the data recorded on the magnetic tape is reproduced.

Here, the magnetic head 10 according to the present embodiment
In the above, a fogging prevention groove 16 is formed in the abutting surface of the core half 12. Thereby, as shown in FIG. 4, for example, when the magnetic head 10 is disposed as a reproducing head with respect to the rotary drum 40 in the vicinity of the recording head 41, fogging due to the magnetic field jumping from the recording head 41 is reduced. Will be reduced. Here, according to experiments by the present inventors, when the depth Dp of the winding groove 11a of the core half body 11 is constant, the depth difference between the depth Dp of the winding groove 11a and the depth DP2 of the fogging countermeasure window 16 is determined. FIG. 5 shows the relationship between Mr and fog. In FIG. 5, it can be seen that the fog becomes substantially minimum when the depth difference Mr is around 30 to 40 μm. Therefore, the depth difference Mr of the fogging prevention groove 16 with respect to the winding groove 11a is 30
It is desirable to set the thickness to 40 μm.

FIG. 6 shows a second embodiment of the magnetic head according to the present invention. In FIG. 6, since the configuration of the portions denoted by the same reference numerals as those in the first embodiment is common, the overlapping description will be omitted, and the description will focus on the differences. In FIG. 6, the magnetic head 50 has substantially the same configuration as the magnetic head 10 shown in FIG. 1, except that the core half 12 is formed narrow in the tape sliding direction and has a winding guide groove. However, the configuration is different in that the number of turns of the coil 15 increases correspondingly with the decrease in the core volume.

According to this configuration, the magnetic head 10 shown in FIG.
The fogging is suppressed by forming the fogging countermeasure groove 16 as in the case and increasing the number of turns of the coil wound around the smaller core half as in the conventional case.

FIG. 7 shows a third embodiment of the magnetic head according to the present invention. In FIG. 7, since the configurations of the portions denoted by the same reference numerals as those in the first embodiment are common, the overlapping description will be omitted, and the differences will be mainly described. In FIG. 7, the magnetic head 60 has substantially the same configuration as the magnetic head 10 shown in FIG. 1, but the gap-side edge 61a of the anti-fogging groove 61 formed in the core half 12 has a winding groove. Similar to 11a, the configuration is different in that it is formed to extend obliquely to the gap side toward the abutting surface. In this case, the fogging prevention groove 6
1 will also act as a winding groove.

According to this configuration, similarly to the magnetic head 10 shown in FIG. 1, the fogging prevention groove 61 suppresses the fogging, and the gap side edge 61a of the fogging prevention groove 61 is formed obliquely. Fog prevention groove 61
In the formation, the occurrence of chipping is suppressed, so that an accurate depth is formed and the yield is improved.

FIG. 8 shows a fourth embodiment of the magnetic head according to the present invention. In FIG. 8, since the configurations of the portions denoted by the same reference numerals as those in the first embodiment are common, the duplicate description will be omitted, and the description will focus on the differences. 8, the magnetic head 70 has substantially the same configuration as the magnetic head 10 shown in FIG. 1, except that the edge 71a on the gap side of the anti-fogging groove 71 formed in the core half 12 has a winding groove. Similarly to 11a, it is formed so as to extend obliquely to the gap side toward the abutting surface, and the edge 71b in the length direction of the fogging prevention groove 71 corresponds to the edge 71a on the gap side. They are different in that they are inclined.

According to this structure, similarly to the magnetic head 10 shown in FIG. 1, the fogging prevention groove 71 suppresses the fogging, and the gap-side edge 71a of the fogging prevention groove 71 is formed obliquely. Fog prevention groove 71
The formation of chipping is suppressed, and the edge 71b in the longitudinal direction is inclined corresponding to the edge 71a on the gap side.
Since it is formed by using a grinding wheel for processing, the grinding wheel for processing the anti-fogging groove 16 does not need to be separately provided, and the cost is reduced. In this case, the fogging prevention groove 7
1 is a fogging countermeasure groove 7 whose width is narrowed below.
Since the fogging suppression effect 1 is effective near the depth Dp of the winding groove 11a, the fogging suppression does not deteriorate.

In the above-described embodiment, each of the magnetic heads 10, 50, 60, and 70 is made of a single magnetic material such as ferrite, but is provided with a metal magnetic film on the abutting surface of the core half. It is apparent that the present invention can be applied to a so-called MIG head or a so-called laminate head having a laminated structure.

[0036]

As described above, according to the present invention, the antifogging groove is provided on the butting surface of the other core half opposite to the winding groove formed on the butting surface of one core half. Is formed, the effect of the magnetic field jumping from the recording head is reduced, and the occurrence of fogging is suppressed, for example, even when the recording head is disposed close to the recording head. Further, according to the present invention, the magnetic head according to the present invention is manufactured with almost no change in the manufacturing process of the conventional magnetic head, so that an increase in cost is suppressed. Thus, according to the present invention, it is possible to provide a magnetic head and a method of manufacturing the same, which are capable of effectively suppressing fogging due to the influence of an external magnetic field such as an adjacent recording head.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing the overall configuration of a first embodiment of a magnetic head according to the present invention.

FIG. 2 is a process chart sequentially showing a manufacturing process of each core half block in one embodiment of a manufacturing process of the magnetic head of FIG. 1;

FIG. 3 is a process chart sequentially showing a manufacturing process of a magnetic core block after bonding in one embodiment of the manufacturing process of the magnetic head of FIG. 1;

FIG. 4 is a schematic sectional view showing a state in which the magnetic head of FIG. 1 is arranged close to a recording head of a rotary drum.

FIG. 5 is a graph showing the relationship between the depth difference Mr and fog in the magnetic head of FIG. 1;

FIG. 6 is a schematic side view showing the configuration of a second embodiment of the magnetic head according to the present invention.

FIG. 7 is a schematic side view showing the configuration of a third embodiment of the magnetic head according to the present invention.

FIG. 8 is a schematic side view showing the configuration of a fourth embodiment of the magnetic head according to the present invention.

FIG. 9 is a schematic side view showing an overall configuration of an example of a conventional magnetic head.

[Explanation of symbols]

10, 50, 60, 70 ... magnetic head, 11, 1
2, 51: core half, 11a: winding groove, 11
b, 12b: winding guide groove, 13: gap,
14, 15,... Coil, 16, 32, 61, 71,.
.Fogging countermeasure grooves, 20, 30,.
..Track width regulating groove, 22 ... winding groove, 23 ...
Bonded glass, 24: sliding surface, 25: magnetic core block, 61a, 71a: gap side edge.

Claims (9)

[Claims] 1. A pair of core halves are joined by abutting each other to form a gap at one end on a sliding surface side to be brought into contact with a magnetic recording medium, and a winding window is formed below the gap. As described above, a magnetic core made of a magnetic material having a winding groove on a mating surface of at least one core half, and a first winding wound around the winding groove and the outer surface of the one core half. And the other core half has a fogging prevention groove formed on its abutting surface so as to face at least near the edge of the winding groove of the one core half on the gap side. A magnetic head comprising: 2. The fogging prevention groove of the other core half,
2. The magnetic head according to claim 1, wherein the magnetic head has a depth greater than a winding groove of the one core half. 3. The magnetic head according to claim 1, wherein a depth difference between the depth of the fogging prevention groove and the depth of the winding groove is approximately 30 to 40 μm. 4. A second coil is wound around the fog prevention groove and the outer surface of the other half of the core, and the number of turns of the coil on the recording head side is the number of turns of the coil on the side opposite to the recording head. 2. The magnetic head according to claim 1, wherein the number is smaller. 5. The magnetic head according to claim 1, wherein the edge on the gap side of the fogging countermeasure groove is formed so as to extend obliquely toward the gap side toward the abutting surface. . 6. The magnetic head according to claim 1, wherein a metal magnetic film and a gap film are formed on the joint surface of the core half, the track width regulating groove, and the surface of the winding window. 7. A first step of forming a winding groove or a fogging prevention groove at a joining surface of two core halves, respectively, and the two core halves are opposed to each other with a gap material interposed therebetween. A second step of forming a magnetic core block by joining the winding windows formed by the grooves to form a magnetic core block, and polishing the end face of one side of the magnetic core block to form a slide having a predetermined curvature. A third step of processing the moving surface, a fourth step of cutting the magnetic core block by chip thickness cutting to cut out individual magnetic heads, and passing around at least one core half through the winding window. And a fifth step of winding a coil. 8. The method of manufacturing a magnetic head according to claim 7, wherein in the first step, the fogging prevention groove is formed by a grindstone for machining a winding groove. 9. The method according to claim 7, wherein after the first step, a metal magnetic film and a gap film are formed on a joint surface of each core half.