JPH076314A - Magnetic head - Google Patents

Abstract

PURPOSE:To provide a magnetic head having a highly accurate bonding between a core where a magnetic gap is formed and a part where a magnetic path is formed and capable of simplifying a constitution. CONSTITUTION:A head core 10 is formed by bonding core pieces 11a, 11b, 12a and 12b and a magnetic gap 11G for recording/ reproducing and a magnetic gap 12G for erasing are formed. A slider 20 is bonded to the side of the head core 10. A supporting block 30 is integrally formed of a ferritic material, etc., and the respective tip surfaces 32a, 33a and 34a of magnetic path leg parts 32, 33 and 34 and the tip surface 35a of a supporting leg part 35 are placed on the highly accurate same surface. Then, the tip surfaces 32a, 33a and 34a of the magnetic path are bonded to the back surface of the head core 10 and the tip surface 35a of the supporting leg part 35 is bonded surfacely to the back surface of the slider 20. The magnetic leg part and the back part of the head core 10 are bonded closely and highly accurately and thus, the reluctance is made smallest at this joined part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head which faces a magnetic recording medium such as a floppy disk to record or reproduce information, and further erases information, and particularly to a head core for forming a magnetic gap. The present invention relates to a magnetic head having a structure capable of being joined with a magnetic path forming portion supporting the head core with high accuracy.

[0002]

2. Description of the Related Art FIG. 7 is an exploded perspective view showing a magnetic head used in a conventional floppy disk device. This magnetic head has a recording / reproducing core 1 and an erasing core 2. The recording / reproducing core 1 includes a T-type core 1a and an I-type core 1
and b, and a magnetic gap 1G for recording / reproduction is formed at the joint. The erasing core 2 has a symmetrical shape with the recording / reproducing core 1, and a T-shaped core 2a and an I-shaped core 2b are joined to each other to form a magnetic gap 2G for erasing. The two I-shaped cores 1b and 2b are magnetically separated and bonded by an adhesive glass 3.

A bobbin 4 around which a recording / reproducing coil C1 is wound is mounted on the leg portion of the T-shaped core 1a.
A bobbin 5 around which an erasing coil C2 is wound is attached to the leg portion of the. The back core 6 is joined to the leg side surfaces of the T-shaped cores 1a and 2a and the I-shaped cores 1b and 2b protruding downward from the bobbins 4 and 5, respectively. In the back core 6, the two core plates 6a and 6b are bonded glass 7
It was joined by. One core plate 6a
Is laterally joined to the lower ends of the T-shaped core 1a and the I-shaped core 1b, and the T-shaped core 1a and the I-shaped core 1b are magnetically joined. Similarly, the core plate 6b is the T-shaped core 2a.
And the I-shaped core 2b are laterally bonded to the lower end of the I-shaped core 2b, and the T-shaped core 2a and the I-shaped core 2b are magnetically bonded. The recording / reproducing core 1 and the erasing core 2 are sandwiched by the non-magnetic sliders 8 and 9 to form a magnetic head. The magnetic head is supported by a gimbal and is used in a state where the upper surface side of FIG. 7 is in sliding contact with a magnetic recording medium such as a floppy disk.

[0004]

In the magnetic head having the above structure, the plate-shaped back core 6 is laterally joined to the lower ends of the legs of the T-shaped cores 1a and 2a and the I-shaped cores 1b and 2b. , T-shaped cores 1a, 2a and I-shaped cores 1b, 2b are vertically long in the drawing in order to secure the mounting portions for bobbins 4, 5. Therefore, it is difficult to ensure the flatness of the lower end side surface of each leg portion, and the lower end side surface of each leg portion and the core plates 6a and 6b are not completely surface-bonded at all positions. Therefore, the T-shaped cores 1a and 2a and the I-shaped core 1
b, 2b legs and the core plate 6a of the back core 6,
The surface joining accuracy with 6b becomes poor, and the magnetic resistance increases at this surface joining portion. When the magnetic resistance increases in the magnetic path and a substantial gap is formed, noise is mixed into the magnetic path through this gap, and the recording / reproducing characteristics are affected.

Of the deterioration of the recording / reproducing characteristics caused by the increase of the magnetic resistance in the magnetic path, a particular problem is the asymmetry of the reproduced waveform. This will be conceptually described with reference to FIG. First, even when the recording current applied to the coil C1 is a rectangular wave, the waveform of the current actually flowing in the coil C1 becomes blunt as shown in FIG. 6A due to the inductance of the coil.

When a portion having a high magnetic resistance is formed between the leg portion of the core and the back core 6, DC is generated from this portion.
The component noise is easily mixed. When this DC component noise enters, the recording current waveform shown in FIG. 6A has a substantial bias, and the zero point of the alternating current shifts from the original position of O1 to the position of O2. When the magnetic head reproduces the magnetic recording medium recorded by the recording current, the waveform shown in FIG. 6B is obtained. However, due to the bias of the DC component, the peak of the reproduced waveform is originally generated. On the time axis from the position indicated by the solid line to the position indicated by the broken line. The asymmetry of the waveform due to this shift amount is expressed as asymmetry, for example, (n.sec; nanosecond). Such deterioration of asymmetry is a major cause of recording or reproducing errors of magnetic information, and becomes more serious as the recording density on the magnetic recording medium increases.

Further, in the magnetic head shown in FIG. 7, since the T-shaped cores 1a and 2a and the I-shaped cores 1b and 2b are thin and long, it is very difficult to cut the bonded cores. It's difficult. Further, since the number of parts of the core increases, both the cost of component parts and the cost due to the manufacturing process are high.

The present invention solves the above-mentioned problems of the prior art, and has a structure capable of increasing the surface joining accuracy in the joining portion of the magnetic bodies forming the magnetic path to minimize the magnetic resistance in this joining portion. In addition, it is an object of the present invention to provide a magnetic head whose overall structure is simplified and manufacturing cost can be reduced.

[0009]

A magnetic head according to the present invention comprises a head core having a magnetic gap on a surface facing a magnetic recording medium, a slider bonded to the head core and facing the magnetic recording medium, A support block that supports the head core and the slider, and the support block has a magnetic path leg portion that is surface-bonded to the back surface of the head core on both sides of the magnetic gap and a support leg portion that supports the slider. In addition, a coil is attached to the magnetic path leg portion.

Further, in the case where two magnetic gaps are formed in the head core, the support block has three magnetic paths which are surface-bonded to the back surface of the head core at the middle of the two magnetic gaps and the outside of the two magnetic gaps. It is possible to provide a structure in which the leg portion and the support leg portion that supports the slider are provided, and each magnetic path leg portion and the support leg portion are integrally formed of a magnetic material.

[0011]

In the above means, the magnetic path leg portion is formed on the support block for supporting the head core and the slider from the back surface side, and the tip end surface of this magnetic path leg portion is surface-bonded to the back surface of the head core on both sides of the magnetic gap. There is. As a result, the contact area between the magnetic path leg portion and the head core can be increased. Further, since the flatness of the tip end surface of the magnetic path leg portion can be increased and the back surface of the head core can also be processed to have a high area degree, the surface joining accuracy of the both can be made extremely high, and the magnetic resistance at the joining portion can be reduced as compared with the conventional case. be able to.

Further, the head core can be formed in a square bar shape, for example.
The structure of the head core is simple and the manufacturing is very easy. Since the entire structure is composed of three members, that is, the head core, the slider and the support block, the number of parts is minimized.
Therefore, even a device having two magnetic gaps as described in the second means can be manufactured at low cost.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the magnetic head of the present invention, and FIG. 2 is an exploded perspective view thereof. Reference numeral 10 in the drawing is a head core. The head core 10 has a rectangular bar shape. The square bar-shaped head core 10 has a recording / reproducing core portion 11 and an erasing core portion 12. The recording / reproducing core portion 11 and the erasing core portion 12 are magnetically separated and bonded and fixed via an adhesive glass 14. The recording / reproducing core unit 11 has core pieces 11a and 11b, and the erasing core unit 12 has core pieces 12a and 12b.
All the core pieces are made of a ferromagnetic material such as ferrite and formed into a substantially hexahedral shape. On the surface (a) in sliding contact with the magnetic recording medium, there are provided a recording / reproducing magnetic gap 11G which is a joint between the core pieces 11a and 11b, and an erasing magnetic gap 12G which is a joint between the core pieces 12a and 12b. Is appearing. Mold glass 13a and 13b are filled in the grooves formed on both sides of the magnetic gaps 11G and 12G, respectively.

A slider 20 is joined to the head core 10. The slider 20 is made of a non-magnetic material such as a ceramic material. Slider 2
A groove 21 is formed on the side end surface of 0, and the head core 10 and the slider 20 are fixed to each other by an adhesive glass 22 filled in the groove 21. The head core 10 and the slider 20 are flush with each other on the surface (a) in sliding contact with the magnetic recording medium. Further, on this surface (a), the slider 20
A sliding groove 23 is formed in the. The head core 10 and the slider 20 have a support block 30 on the back surface (b) side.
It is supported by. In the support block 30 shown in FIGS. 1 and 2, all parts are integrally formed of a ferromagnetic material such as ferrite.

The support block 30 includes a bottom plate portion 31 having a wide planar bottom surface 31a, and the bottom plate portion 31.
The magnetic path leg portions 32, 33, and 34, which are all square pole-shaped and project upward from one edge portion, and the plate-shaped support leg portion 35, which upwardly projects from the other edge portion of the bottom plate portion 31. It is configured. The front end surfaces 32a, 33a, 34a of the magnetic path leg portions 32, 33, 34 and the front end surface 35a of the support leg portion 35 are surface-machined with high precision so that they can be located on the same plane. On the other hand, the head core 10 and the slider 20, which are joined to each other, also have the back surface (b) formed on the same surface with high flatness. And the tip surface 3 of the magnetic path leg portion 32
2a is a magnetic gap 11G and 12G of the head core 10.
Of the magnetic path legs 33 and 34 are surface-bonded to the back surfaces of the magnetic gaps 11G and 12G of the head core 10. Further, the front end surface 35a of the support leg portion 35 has a slider 2
It is surface-bonded to the back surface of 0. Then, as shown in FIG. 1, the head core 10 and the slider 20, and the support block 30 are fixed to each other by the mold glass M.

In the assembled state as shown in FIG. 1, the bobbin 41 around which the recording / reproducing coil C1 is wound is attached to the magnetic path leg portion 33, and the bobbin 42 around which the erasing coil C2 is wound is magnetic. It is attached to the road leg portion 34. Then, the bottom surface 31 a of the bottom plate portion 31 of the support block 30 is fixed by being bonded to the gimbal 45 or the like. With this magnetic head,
A magnetic path for recording and reproduction is formed by the core piece 11a, the magnetic path leg portion 33, the bottom plate portion 31, the magnetic path leg portion 32, and the core piece 12a, the magnetic path leg portion 34, the bottom plate portion 31, the magnetic path. The leg 32 and the core piece 12b form a magnetic path for erasing.

Next, an example of a manufacturing process of the magnetic head having the above structure will be described. First, as shown in FIG. 3, ferrite blocks A, B, C, and D are joined together. A plurality of grooves A1 extending in the vertical direction in the drawing are formed at a constant pitch on the joint surface of the ferrite block A, and a plurality of grooves B1 also extending in the vertical direction in the drawing are formed in the ferrite block B at the same pitch as the groove A1. . A plurality of grooves A2 extending in the horizontal direction in the drawing are formed at a constant pitch on the joint surface of the ferrite block A. Similarly, a groove C1 extending in the vertical direction in the drawing is formed in the ferrite block C, and a groove D1 extending in the vertical direction in the drawing and a groove D2 extending in the horizontal direction in the drawing are also formed in the ferrite block D.

A thin glass material is interposed at the joining boundary (c) between the surfaces left at the joining portion of both ferrite blocks A and B due to the processing of the grooves A1, A2 and the groove B1.
Similarly, a thin glass material is also interposed at the bonding boundary (c) between the surfaces left at the bonding portions of both ferrite blocks C and D by processing the groove C1 and the grooves D1 and D2. This junction boundary (c) later becomes the recording / reproducing magnetic gap 11G having a predetermined track width and a predetermined gap depth. The junction boundary (d) later becomes the erasing magnetic gap 12G having a predetermined track width and a predetermined gap depth. Grooves A1 and A of ferrite blocks A and B, respectively
Mold glass 13a is filled in the joint space between the groove 2 and the groove B1, and the groove C1 of each of the ferrite blocks C and D is filled.
Mold glass 13b is filled in the joint portion between the ferrite blocks A, B, C and D, and a bonding glass 14 is interposed between the facing surfaces of the ferrite blocks B and C so that the ferrite blocks A, B, C and D are mutually connected. It is fixed.

Ferrite blocks A, B, shown in FIG.
The block body in which C and D are joined is L1, L2, L3, ...
As shown in FIG.
A plurality of head core blocks E shown in are manufactured. Next, the ceramic block F and the head core block E are joined. A plurality of laterally extending grooves 21, 21, ... Are formed on the joint surface of the ceramic block F, and the blocks E and F are fixed by the adhesive glass 22 filled in the grooves 21, 21 ,. It A plurality of sets of bonded bodies of the head core 10 and the slider 20 are cut out by laterally cutting the block in which the blocks E and F are fixed to each other along a cutting line indicated by S1, S2, S3, .... Since the joined body of the head core 10 and the slider 20 is cut out from the joined body of the blocks E and F shown in FIG. 4,
It is easy to process the back surface (b) of this bonded body into the same surface having high flatness over the entire head core 10 and slider 20.

On the other hand, in the support block 30, the upper surface of the ferrite block is surface-machined with high flatness. Then, the magnetic path leg portions 32, 33, 34 and the supporting leg portion 35 are grooved so as to leave the tip surfaces 32a, 33a,
34a and 35a can be flush with each other with high precision.
Alternatively, it is possible to integrally form the support block 30 with a mold by powder processing technology or the like. In this way, the back surface (b) of the joined body of the head core 10 and the slider 20 can be processed into the same surface, and the tip surfaces 32a, 33a, 34a, and 35a of the legs of the support block 30 can be processed into the same surface. 10 and back surface of slider 20 (b)
And the tip surfaces 32a, 33a, 34a, 35a of the legs can be surface-bonded to each other with high precision. Particularly, since the front end surfaces 32a, 33a, 34a of the magnetic path leg portions 32, 33, 34 and the head core 10 can be joined to each other with high accuracy, the recording / reproducing magnetic path and the erasing magnetic path can be used. The magnetic resistance due to surface bonding does not increase.

Next, Table 1 below compares the characteristics of the magnetic head of the embodiment shown in FIG. 1 and the magnetic head of the conventional example shown in FIG. For this comparison, in each of the magnetic heads of the example and the conventional example, the material of the part forming the magnetic path is the same ferrite material, the length of the magnetic path sandwiching the magnetic gap is the same, and the coils C1 and C
The number of turns of 2 was set to be the same, and the gap width of the magnetic gap was made the same as the gap width (track width) and the gap depth. The measurement was carried out 5 times for each of recording and reproduction on a 4 Mbyte floppy disk, and the average value was obtained to compare the characteristics.

[0022]

[Table 1]

The 2F output shown in Table 1 above is a peak-to-peak value (mV), but the frequency of the 2F output is 500 kHz because it is a 4 Mbyte specification.
The resolution is the ratio (%) obtained by dividing the 2F output by the 1F output. The frequency of the 1F output is 250 kHz. And asymmetry is time (n
sec). As shown in Table 1, it can be seen that the magnetic head of the embodiment of the present invention shown in FIG. 1 is significantly improved in asymmetry as compared with the conventional example. This is the head core 10 and the magnetic path legs 32, 3 of the support block.
This means that the joint portion with 3, 34 is in surface contact with high precision. Further, it can be seen that the present invention is comparable to the conventional example in the 2F output and the resolution and can exhibit the same characteristics.

FIG. 5 shows another embodiment of the support block 20 in the magnetic head of the present invention. In this embodiment, a part of the magnetic path leg portion 33 forming the recording / reproducing magnetic path and the central magnetic path leg portion 32 are integrally formed by a U-shaped ferrite H, and an erasing magnetic path is formed. A part of the magnetic path leg portion 34 and the magnetic path leg portion 32 that form the path are integrally formed by a U-shaped ferrite I, and both ferrites H and I are separate. The boundary between the two ferrites H and I is magnetically separated and adhered by the adhesive glass 51. Further, the bottom plate portion 31 and the support leg portion 35 are integrally formed by the ferrite J, and the L-shaped ferrite J
And the ferrites H and I are adhered to each other by the adhesive glass 52. This support block is made up of ferrite H
And I and J are joined together, and then the leg end faces 32a, 33 are joined.
It can be manufactured by processing a, 34a and 35a on the same surface and then grooving so as to leave each leg 32, 33, 34, 35.

The member J forming the bottom plate portion 31 and the support leg portion 35 does not necessarily have to be ferrite, but can be made of a non-magnetic material such as plastic or ceramic. However, when the member J is made of a magnetic material such as ferrite, the supporting leg portion 35 can function as a shield plate. This point is the same in the embodiment of FIG. In the above embodiment, the head core 1
Two magnetic gaps 11G and 12G are formed at 0, but one magnetic gap may be formed.

[0026]

As described above, since the magnetic path leg portion of the support block forming the magnetic path is surface-bonded to the back surface of the head core, the adhesiveness of the bonding surface can be increased and the magnetic resistance in the magnetic path can be improved. There is no raised part. Therefore, characteristics such as asymmetry are improved as compared with the conventional one. Further, since the head core can be formed in, for example, a quadrangular prism shape, the structure of the head can be simplified and the manufacturing thereof becomes easy.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a magnetic head of the present invention,

FIG. 2 is an exploded perspective view of the magnetic head shown in FIG.

3 is a perspective view showing an example of a process for manufacturing a head core of the magnetic head shown in FIG.

4 is a perspective view showing an example of a process for manufacturing a head core of the magnetic head shown in FIG.

FIG. 5 is a perspective view showing another embodiment of the support block,

6 (A) and (B) are diagrams for explaining asymmetry, which is one of conventional problems;

FIG. 7 is an exploded perspective view of a conventional magnetic head,

[Explanation of symbols]

 10 head core 11 recording / reproducing core portion 12 erasing core portion 11a, 11b, 12a, 12b core piece 11G magnetic gap for recording / reproducing 12G magnetic gap for erasing 20 slider 30 support block 32, 33, 34 magnetic path leg portion 35 support Leg C1, C2 coil

Claims (2)

[Claims] 1. A head core in which a magnetic gap appears on a surface facing a magnetic recording medium, a slider joined to the head core and facing the magnetic recording medium, and a support block supporting the head core and the slider. The support block includes a magnetic path leg portion that is surface-bonded to the back surface of the head core on both sides of the magnetic gap, and a support leg portion that supports the slider, and a coil is formed on the magnetic path leg portion. A magnetic head characterized by being mounted. 2. The head core has two magnetic gaps formed therein, and the support block has three magnetic path legs that are surface-bonded to the back surface of the head core at the middle of the two magnetic gaps and the outside of the two magnetic gaps, respectively. 2. A magnetic head according to claim 1, wherein the magnetic head and the support leg are provided to support the slider, and the magnetic path leg and the support leg are integrally formed of a magnetic material.