JPH06162434A - Magnetic head and its manufacture - Google Patents

Abstract

PURPOSE:To prevent the interference of a magnetic flux owing to a boundary part with a non-magnetic body existing in the vicinity part of a magnetic gap and the flux owing to the magnetic gap on a medium slidable contact surface. CONSTITUTION:A pair of cores 15a and 15b consisting of a ferromagnetic body such as ferrite, etc., are integratedly joined, the magnetic gap (g) is generated at the top end joint part, the non-magnetic bodies 17a and 17b are joined and fixed at the outside end surfaces of the cores 15a and 15b which are located along the joint direction and the medium slidable contact surface 18 is generated at the top end so that a thin sheet-shape core chip 15 is formed. At the outside end surface in the magnetic gap vicinity part of the core 15a, an inclined surface 19 making angle with the medium slidable contact surface 18 is generated, glass 20 is filled between the inclined surface 19 and the non-magnetic body 17a and the boundary part 29 of the core 15a and the non-magnetic body 17a is generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head and a method of manufacturing the same, and more particularly, to a structure of a core chip of a magnetic head used in an FDD device and a method of manufacturing the core chip.

[0002]

2. Description of the Related Art For example, a magnetic head mounted on an FDD device for recording / reproducing information comprises a core chip (1) as shown in FIG. This core chip (1) includes a pair of cores (1a) (1b) made of a ferromagnetic material such as ferrite,
A low melting point glass (2) is formed on the top end bonding portion through a non-magnetic material film (not shown) such as SiO _{2 serving as a} gap spacer.
To form a magnetic gap g having a predetermined track width and protected by the low melting point glass (2). Further, a non-magnetic material (3a) (3b) such as ceramic is adhered and fixed to the outer end surface along the joining direction of the cores (1a) (1b), and the top end surface that is flush with the cores (1a) (1b) is attached. Set as the medium contact surface (4).

In manufacturing the core chip (1) having the above structure, first, as shown in FIG. 11A, a pair of core blocks (5) made of a ferromagnetic material such as ferrite is used.
Prepare a) (5b) [a long one along the direction orthogonal to the paper] and engrave the winding groove (6) in one core block (5b). In the figure, (7) is a joining taper portion formed on one core block (5b). And
A plurality of track grooves (8a) (8b) are engraved on the joint surface of both core blocks (5a) (5b) leaving a predetermined track width.

Next, as shown in FIG. 11 (b), from the state of FIG. 11 (a), the joint surfaces of both core blocks (5a) and (5b) are joined to _each other with SiO ₂ or the like serving as a gap spacer. After coating a non-magnetic film (not shown), butted upside down, the winding groove (6) of the core block (5b)
A rod-shaped low-melting glass (2) is placed on the lower part of and the taper part (7). Then, both core blocks (5a) (5b) are heated while being pressed from the outside to melt the low melting point glass (2) and fill the track grooves (8a) (8b) and the taper portion (7). As a result, the core blocks (5a) and (5b) are joined and integrated, and further, the side portions of the core blocks (5a) and (5b) are cut and removed as shown by a chain line in the figure.

Then, as shown in FIG. 11C, the core blocks (5a) and (5b) joined and integrated with the low melting point glass (2) are turned upside down from the state of FIG. Non-magnetic material blocks (9a) (9b) such as ceramics are adhesively fixed to the outer end surfaces of the blocks (5a) (5b) along the joining direction, and the connecting lower portions of both core blocks (5a) (5b) are cut and removed.
Finally, the core block (5a) (5
b) and the non-magnetic material blocks (9a) and (9b) are ground by a predetermined amount to form a medium sliding contact surface (4) that is flush with each other and sliced at a predetermined pitch (not shown) A core chip (1) shown in 10 is obtained.

[0006] The core chip (1) thus obtained
As shown in FIG. 12, the coil (10) is attached to the leg of one core (1a), and the legs of both cores (1a) and (1b) are connected by the back core (11) to close the magnetic field. A path is formed, and information is recorded / reproduced on / from the recording medium (m) running on the medium sliding contact surface (4) by the magnetic flux φ leaking from the closed magnetic path in the magnetic gap g.

[0007]

By the way, in the conventional magnetic head, the non-magnetic material (3a) adhered and fixed to the core (1a) is provided in the vicinity of the magnetic gap g on the medium sliding contact surface (4).
Since there is a boundary portion (12) between the recording medium (m) and the recording medium (m) traveling on the medium sliding contact surface (4), the boundary portion (12) shown in FIG.
As shown in FIG. 3, the boundary portion (12) described above becomes a pseudo gap, and the magnetic flux φ ′ is induced from the recording medium (m) along the boundary surface (13), and the magnetic flux φ ′ is generated by the coil (10).
It was difficult to reproduce accurate information because the noise flowed in and noise was generated during reproduction. This is because the track width when the boundary (12) is regarded as a pseudo gap is the core chip (1).
Is larger than the track width of the magnetic gap g, so that the above-mentioned noise has a significant adverse effect on the reproduced information.

Therefore, the present invention has been proposed in view of the above problems, and an object of the present invention is to provide a magnetic flux due to a boundary portion with a non-magnetic material existing in the vicinity of the magnetic gap on the medium sliding contact surface. It is an object of the present invention to provide a magnetic head and a method for manufacturing the same, which can prevent interference between the magnetic flux and the magnetic flux due to the magnetic gap.

[0009]

As a technical means for achieving the above object, a magnetic head according to the present invention has a pair of cores made of a ferromagnetic material bonded and integrated with each other, and a magnetic gap is formed at a top end bonding portion thereof. In the thin plate core chip formed with a non-magnetic material adhered and fixed to the outer end surface of the core along the joining direction, and a medium sliding contact surface is formed on the top end, the medium is formed on the outer end surface in the vicinity of the magnetic gap of the core. It is characterized in that an inclined surface that forms an angle with the sliding contact surface is formed, and glass is filled between the inclined surface and the non-magnetic material to form a boundary portion between the core and the non-magnetic material.

In the above magnetic head, the inclined surface formed on the outer end surface of the core in the vicinity of the magnetic gap is a convex curved surface, and the boundary where the medium sliding contact surface and the inclined surface intersect with respect to the magnetic gap. It is desirable to make them non-parallel.

Further, in the manufacturing method according to the present invention, a step of forming an interference prevention groove having an inclined surface in the vicinity of both side surfaces of a pair of core blocks made of a ferromagnetic material and filling the interference prevention groove with glass. And a step of engraving a plurality of track grooves leaving a predetermined track width on the joint surface of the core block,
Filling the track grooves with glass in a state in which both core blocks are bonded to each other with a non-magnetic film serving as a gap spacer interposed therebetween, and a step of joining and integrating them
The method is characterized by including a step of cutting and removing both side surfaces of the joined core block until the glass in the interference prevention groove is exposed, and a step of adhering and fixing the nonmagnetic block to the both side surfaces.

In the above manufacturing method, the step of filling the interference prevention groove with glass and the step of filling the track groove with glass and joining and integrating both core blocks with the glass of the track groove are performed simultaneously, or the interference prevention groove is formed. A step of filling the glass with glass and adhering and fixing the non-magnetic block to the core block with the glass of the interference preventing groove, and a step of filling the track groove with glass and joining and joining both core blocks with the glass of the track groove. It is desirable to engrave the interference prevention groove by rough cutting in the same process or in the step of engraving the interference prevention groove having an inclined surface.

[0013]

According to the present invention, the outer end surface of the core near the magnetic gap is formed with an inclined surface that makes an angle with the medium sliding contact surface. Since the magnetic flux from the recording medium is shallowly guided along the inclined surface at the boundary between the core and the non-magnetic material, it is possible to prevent the magnetic flux guided from the boundary from flowing into the coil. it can.

[0014]

Embodiments of a magnetic head and a method of manufacturing the same according to the present invention will be described with reference to FIGS.

The core chip (15) of the magnetic head of the embodiment shown in FIG. 1 has a pair of cores (15a) and (15b) made of a ferromagnetic material such as ferrite, and SiO ₂ etc. which becomes a gap spacer at the apex junction portion thereof. A low melting point glass (16) is bonded and integrated through a non-magnetic film (not shown) to form a magnetic gap g protected by the low melting point glass (16) and having a predetermined track width. Furthermore, a non-magnetic material (17a) (1a) (1a) (1a) (1a)
7b) is fixed by adhesion, and the top end surface which is flush with the cores (15a) (15b) is used as the medium sliding contact surface (18). Here, an inclined surface (19) forming an angle with the medium sliding contact surface (18) is formed on the outer end surface of the core (15a), and a high surface is provided between the inclined surface (19) and the non-magnetic body (17a). Fill with melting or low melting glass (20).

In manufacturing the core chip (15), first, as shown in FIG. 2 (a), a pair of core blocks (21a) (21b) made of a ferromagnetic material such as ferrite is prepared, and one of the core blocks is prepared. A winding groove (22) is formed in the core block (21b) and a joining taper portion (23) is formed. Then, a plurality of track grooves (24a) (24b) are engraved on the joint surface of both core blocks (21a) (21b) leaving a predetermined track width, and the upper surfaces of the core blocks (21a) (21b) are An interference prevention groove (25) having an inclined surface (19) is engraved, and the interference prevention groove (25) is filled with a high melting point glass (20).

Next, as shown in FIG. 2 (b), from the state of FIG. 2 (a), the joint surfaces of both core blocks (21a) and (21b) are covered with SiO ₂ or the like serving as a gap spacer. After applying a non-magnetic film (not shown), butted upside down, the winding groove (2) of the core block (21b)
The rod-shaped low melting point glass (1
6) Place. And both core blocks (21a) (21
The core block (21) is heated by heating b) from the outer side to melt the low melting point glass (16) and fill the track grooves (24a) (24b) and the taper part (23).
a) (21b) are joined and integrated, and the side portions of the core blocks (21a) (21b) are cut and removed as indicated by the chain line in the figure.

Further, as shown in FIG. 2C, the core blocks (21a) and (21b) joined and integrated with the low melting point glass (16) are turned upside down from the state of FIG. Non-magnetic material blocks (26a) (26b) such as ceramics are adhesively fixed to the outer end faces of the blocks (21a) (21b) along the joining direction, and the connecting lower parts of both core blocks (21a) (21b) are cut and removed. Finally, as indicated by the chain line in the figure, the top surfaces of the core blocks (21a) (21b) and the non-magnetic material blocks (26a) (26b) are ground by a predetermined amount to make the medium sliding contact surface (18) flush. The core chip (15) shown in FIG. 1 is obtained by forming and slicing at a predetermined pitch although not shown.

The core chip (15) thus obtained
As shown in FIG. 3, the coil (27) is attached to the leg of one core (15a), and the legs of both cores (15a) and (15b) are connected by the back core (28) to close the magnetic field. A path is formed and information is recorded / reproduced on / from the recording medium (m) running on the medium sliding contact surface (18) by the magnetic flux φ leaking from the closed magnetic path in the magnetic gap g.

During this reproduction, as shown in FIG. 4, the core (15
The magnetic flux φ'from the recording medium (m) is shallowly induced along the inclined surface (19) at the boundary (29) between the core (15a) and the non-magnetic material (17a) near the magnetic gap in (a). Because it is done
It is possible to prevent the magnetic flux φ ′ induced from the boundary (29) from flowing into the coil (27).

In the method of the present invention, in addition to the above embodiment, the following means may be taken, for example, when the core blocks (21a) and (21b) are joined and integrated.

For example, as shown in FIG. 5, the interference prevention groove (25) is not filled with high melting point glass in the core block (21a).
(21b) are butted, and a rod-shaped low-melting point or high-melting point glass (16) is arranged in the lower part of the winding groove (22) and the taper part (23), and a rod-shaped low-melting point or high-melting point glass (20) is placed. Place in the interference prevention groove (25). In this case, unlike the case described above, either one of the low melting point glass and the high melting point glass may be used. In this state, the core blocks (21a) (21b) are heated while being pressed from the outside, so that the low-melting or high-melting glass (16) is melted and the track grooves (24a) (2
4b) and taper part (23) are filled and both core blocks (21
At the same time as (a) and (21b) are joined and integrated, the low melting point glass or the high melting point glass (20) is melted and filled in the interference prevention groove (25).

Further, as shown in FIG. 6, the core blocks (21a) and (21b) are butted against each other, and a rod-shaped low-melting or high-melting glass (16) is connected to the lower part of the winding groove (22) and the taper part (23). The interference prevention groove (25) on the outer end faces of the core blocks (21a) and (21b) in the state where the non-magnetic block (26) is arranged.
a) and (26b) are arranged, and a rod-shaped low melting point or high melting point glass (20) is arranged in the interference prevention groove (25). In this state, the low melting point glass or the high melting point glass (16) is melted by heating while applying pressure from the outside of the non-magnetic material blocks (26a) (26b) to the track groove (24a).
(24b) and taper part (23) are filled and core block (2
1a) and (21b) are joined and integrated, and at the same time, the low-melting or high-melting glass (20) is melted and filled in the interference prevention groove (25) so that the non-magnetic material blocks (26a) and (26b) become core blocks (21a). ) (21b) is fixed by adhesion.

Next, the core chip (15) of the above-mentioned embodiment
Then, the inclined surface (19) formed on the outer end surfaces of the cores (15a) and (15b) is a flat surface, but the present invention is not limited to this, and, for example, as shown in FIG. It is also possible to make the inclined surface (19 ') a convex curved surface.

When manufacturing this core chip (15), as shown in FIG. 8, the interference prevention groove (2
5 ') is engraved, and the core chip (15) shown in FIG. 7 is obtained by the various steps described above.

Here, when the inclined surface (19 ') is a convex curved surface as described above, when the core chip (15) is manufactured, the interference prevention groove (25') is formed by rough cutting when forming the interference prevention groove (25 '). When the (25 ') is engraved, the surface state of the inclined surface (19') becomes a rough surface, and at the medium sliding contact surface (18), as shown in FIG.
As shown in (4), the boundary between the core (15a) and the glass (20) filled in the interference prevention groove (25 ') is non-parallel [corrugated] with the magnetic gap g. The magnetic flux φ ′ induced from the recording medium (m) at the boundary (29) between the core (15a) and the non-magnetic body (17a) and the magnetic flux φ induced by the magnetic gap g are further prevented from interfering with each other. Can be suppressed. This interference prevention is remarkable because the smaller the angle θ formed by the convex inclined surface (19 ') near the medium sliding contact surface (18), the larger the non-parallel [waveform] of the boundary described above. Becomes

[0027]

According to the present invention, at the time of reproducing information in which the recording medium travels on the medium sliding contact surface, the magnetic flux from the recording medium becomes shallow along the inclined surface at the outer end surface near the magnetic gap of the core. Since it is induced, it will be separated from the magnetic flux induced by the magnetic gap, interference with the magnetic flux due to the magnetic gap can be suppressed as much as possible, and a good reproduction output can be obtained. A good quality magnetic head can be provided.

[Brief description of drawings]

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

FIG. 2 is a front view of a core block for explaining an embodiment of the method of the present invention and is for explaining a manufacturing procedure of the core chip of FIG.

FIG. 3 is a front view showing a relative positional relationship between a magnetic head of the present invention and a recording medium.

FIG. 4 is an enlarged view of a main part of FIG.

FIG. 5 is a front view of a core block shown for explaining another embodiment of the method of the present invention.

FIG. 6 is a front view of a core block shown for explaining another embodiment of the method of the present invention.

FIG. 7 is a perspective view of a core chip showing another embodiment of the magnetic head of the present invention.

FIG. 8 is a front view of a core block shown for explaining a manufacturing procedure of the core chip of FIG.

9 is an enlarged perspective view of an essential part showing a state where the boundary between the core and the glass is not parallel to the magnetic gap [waveform] on the medium sliding contact surface of the core chip of FIG. 7.

FIG. 10 is a perspective view showing a core chip of a conventional magnetic head.

FIG. 11 is a front view of a core block for explaining a conventional manufacturing method and for explaining a manufacturing procedure of the core chip of FIG.

FIG. 12 is a front view showing a relative positional relationship between a conventional magnetic head and a recording medium.

FIG. 13 is an enlarged view of a main part of FIG.

[Explanation of symbols]

 15 core chip 15a, 15b core 17a, 17b non-magnetic material 18 medium sliding surface 19 inclined surface 20 glass 21a, 21b core block 24a, 24b track groove 25 interference prevention groove 26a, 26b non-magnetic material block 29 boundary

Claims (7)

[Claims] 1. A pair of cores made of a ferromagnetic material are joined and integrated, a magnetic gap is formed at the top end joining portion thereof, and a non-magnetic material is adhered and fixed to the outer end surface of the core along the joining direction. In a thin plate core chip having a medium sliding contact surface, an inclined surface that forms an angle with the medium sliding contact surface is formed on the outer end surface of the core near the magnetic gap, and between the inclined surface and the non-magnetic body. A magnetic head characterized in that it is filled with glass to form a boundary between the core and a non-magnetic material. 2. The magnetic head according to claim 1, wherein the inclined surface formed on the outer end surface of the core near the magnetic gap is a convex curved surface. 3. A magnetic head, wherein a boundary at which the medium sliding contact surface and the inclined surface intersect with each other according to claim 1 or 2 is not parallel to the magnetic gap. 4. A step of engraving an interference prevention groove having an inclined surface in the vicinity of both side surfaces of a pair of core blocks made of a ferromagnetic material, and filling the interference prevention groove with glass, and a joint surface of the core block. A step of engraving a plurality of track grooves with a predetermined track width left on the core blocks, and filling the track grooves with glass in a state in which both core blocks have a non-magnetic film serving as a gap spacer on their joint surfaces. A step of butt-joining and unifying, a step of cutting and removing both side surfaces of the joined core block until the glass in the interference prevention groove is exposed, and a step of adhesively fixing the nonmagnetic block to the both side surfaces. A method of manufacturing a magnetic head, comprising: 5. The step of filling the interference prevention groove with glass according to claim 4 and the step of filling the track groove with glass and joining and integrating both core blocks with the glass of the track groove are performed simultaneously. And a method of manufacturing a magnetic head. 6. The step of filling glass in the interference prevention groove according to claim 5 to bond and fix the non-magnetic material block to the core block with the glass of the interference prevention groove, and filling the track groove with glass to both core blocks. A method of manufacturing a magnetic head, characterized in that the step of joining and integrating with the glass of the track groove is performed at the same time. 7. The method of manufacturing a magnetic head according to claim 4, wherein in the step of engraving the interference prevention groove having the inclined surface, the interference prevention groove is engraved by rough cutting.