JPH0696409A - Production of magnetic head - Google Patents

Abstract

PURPOSE:To reduce man-hours and to shorten the time for working as well as to decrease the amt. of the resin to be used and the cost of production by enabling the sufficient packing of the resin into a case by one time of resin pouring. CONSTITUTION:A front face aperture 7 on the front end face of a magnetic head 1A is fitted into a recessed part 19 by imposing an air permeable sheet 2 on the base 19A of the recessed part 19 of a receiving base 18 so as to seal the base and is pressed to the base 18. The base 18 is made of an elastic resin and since the transverse width U of the recessed part 19 is slightly smaller than the transverse width V of the case 6, the base can be held in a tight contact state by fitting the head 1A. The epoxy resin is injected in this state into the space in the case 6 and is thermally cured. The head sealed and fixed by the epoxy resin is thereafter taken out of the base 18 and the sheet 2 is peeled. The magnetic recording medium traveling surface from which the front end face of the head core 8 projects is polished to a smooth surface, by which the magnetic head is produced. As a result, the man-hours and the time for working are reduced by half and the magnetic head is easily produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a VTR voice head,
Alternatively, the present invention relates to a method of manufacturing a magnetic head that can be used for other purposes.

[0002]

6 to 9 show a conventional method for manufacturing a voice control head for a VTR, and FIG. 10 shows the front of FIG. In these figures, reference numeral 5 is a recording / reproducing head portion having a recording / reproducing gap 4 on the front end surface, and the upper head portion 5 of FIG.
Are for recording and reproducing control signals, both made of metal
It is stored in the case 6 (permalloy, etc.). As shown in FIG. 10, a non-magnetic dummy block 25 made of stainless steel or the like is fixed and integrated in advance on the front surface of the case 6. These head portions 5 are configured by mounting a bobbin 9 having a winding 10 wound on a head core 8 formed of a magnetic material such as permalloy or ferrite so as to have a recording / reproducing gap (magnetic gap) 4. There is. In case 6,
The recording / reproducing gap 4 of the recording / reproducing head unit 5 is provided on the front surface (medium traveling surface) on which a magnetic recording medium such as a magnetic tape travels.
Front openings 7 are provided to expose the front end surfaces of the head cores 8 having the above. The head core 8 has a front end 7 having the magnetic gap 4 at the front opening 7.
It is positioned and fixed inside the case 6 through a holder 16 as shown in FIG. Then, the resin casting of the space inside the case 6 of the assembled magnetic head 1A is performed as described below.

First, as shown in FIG. 6, a first resin casting is performed on the assembled magnetic head 1A.
That is, the epoxy resin 14 is injected into the space inside the case 6 and cured by heating. At this time, as shown in FIG. 7, some epoxy resin 14 flows out and falls from the gap 12 between the tip of the head core 8 and the front opening 7 until the epoxy resin 14 is cured. Then, the epoxy resin 14 is cured in a state of being hung on the tip portion of the head core 8 to obtain the magnetic head 1B in which the gap 12 between the tip of the head core 8 and the front opening 7 is stopped. However, a space 17 is formed in the upper part of the case 6 for the resin to flow out.

Next, as shown in FIG. 8, the magnetic head 1B
To the second resin casting. That is, the epoxy resin 14A is injected again into the space 17 formed by the resin flowing out and cured by heating, and as a result, the space 17 is filled.
The inside of the case 6 is sealed. Then, epoxy resin 1
The magnetic recording medium running surface of the magnetic head 1C, which is sealed and fixed by 4, 14A and in which the tip end surface of the head core 8 is projected, is polished into a smooth surface, so that the completed magnetic head 1D of FIGS. Composed.

[0005]

By the way, in the case of the above-mentioned conventional manufacturing method, the two-molding method in which the epoxy resin is used to fill the space in the case 6 with the two-time casting is used. However, various problems have occurred in this manufacturing method. First, in the two-time molding method, steps such as resin injection and heat curing are performed twice, so that it takes time to perform the work, and equipment such as a dryer is required twice in each step. Further, when the resin is cast for the first time, the resin flows out from the case and is cured in a state where it hangs down at the tip, so that the resin is wasted and a large amount of resin is required. Also, the kneading work before the resin injection is required twice. Further, in the polishing process of the running surface of the magnetic recording medium after the case is sealed with resin, since the resin is hardened in a state that the front end face is hung down, rough polishing requires time.

In view of the above points, the present invention makes it possible to sufficiently fill the case with the resin by one-time resin casting when manufacturing a magnetic head having a structure in which the case is filled with the resin, thereby reducing the number of steps. An object of the present invention is to provide a method of manufacturing a magnetic head, which can shorten the working time, reduce the amount of resin used, and reduce the product cost.

[0007]

In order to achieve the above-mentioned object, a method of manufacturing a magnetic head according to the present invention comprises a case in which a head core is exposed to a front opening of a case and the front opening is marked with a breathable sheet. The space in the case is filled with the resin once. In this case, a pedestal having a first recess formed by forming a concave surface that substantially corresponds to the curved surface of the front surface of the case as a bottom surface is used, and the breathable sheet is placed on the concave surface of the pedestal and the breathability is improved. The case with the head core may be placed on a sheet in an overlapping manner to seal the front opening.

[0008]

In the method of manufacturing a magnetic head according to the present invention, the head core is arranged so as to face the front opening of the case, and the front opening is covered with the breathable sheet.
The space in the case is sealed with a resin, and by sealing the front opening of the case with a breathable sheet, it is possible to prevent the resin from flowing out of the case opening when the resin is injected into the case. it can. Therefore, since the space inside the case can be sealed with a single resin casting, the resin kneading work and the dryer, etc., required twice as compared with the conventional manufacturing method in which the resin casting is performed twice. The equipment of is enough for one time,
The man-hours and working time are halved, and the amount of resin used can be reduced by eliminating waste of the resin used. In addition, since the amount of the resin that flows out from the front opening and projects to the tip surface of the case and hardens is small compared to the conventional manufacturing method, the processing time for polishing the running surface of the magnetic recording medium can be shortened.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a magnetic head manufacturing method according to the present invention will be described below with reference to the drawings.

1 to 5 show a method of manufacturing a magnetic head according to the present invention, and the front view of FIG. 5 showing the completed magnetic head is the same as FIG. In these figures,
1A is an assembled magnetic head in which a recording / playback head unit 5 (for voice recording / playback and control signal recording / playback) is housed and fixed in a case 6 made of metal (permalloy or the like), and a magnetic head for VTR voice control. It is an example of what is used for. The head portion 5 is constructed by mounting a bobbin 9 having a winding 10 wound on a head core 8 formed of a magnetic material such as permalloy or ferrite so as to have a recording / reproducing gap (magnetic gap) 4. There is. As shown in FIG. 3, a case 6 in which a non-magnetic dummy block 25 made of stainless steel or the like is fixed and integrated on the front surface, has a front surface (medium traveling surface) on which a magnetic recording medium such as a magnetic tape travels.
A front opening 7 is provided for exposing the front end surface of the head core 8 having the recording / reproducing gap 4 of the recording / reproducing head section 5. And the head core 8 is
It is positioned and fixed via a holder 16 inside the case 6 so that the front end surface having the magnetic gap 4 faces the front opening 7. Then, the resin casting of the space inside the case 6 of the assembled magnetic head 1A is performed as described below.

First, as shown in FIG. 1, a pedestal 18 made of an elastic resin (rubber-like silicon resin or the like) that is non-adhesive to the epoxy resin to be filled is prepared. This cradle 1
A first concave portion 19 into which a tip portion of the case 6 of the magnetic head 1A is fitted is formed in the concave portion 8.
The bottom surface 19A is a concave surface that is substantially the same curved surface as the front surface of the case. The bottom surface 19A is provided with a second recess 20 for avoiding the head core 8 and the dummy block 25 protruding from the front surface of the case of the magnetic head 1A (to prevent contact) and for allowing air to escape. further,
The pedestal 18 is formed with a through hole 26 for communicating the inside of the second recess 20 with the outside. The width U of the recess 19 is
Is set to be slightly smaller than the case lateral width V before the case 6 is mounted. Preferably 0 <V−U ≦
It is desirable to set it to 0.15 mm.

As shown in FIGS. 2 and 3, in the magnetic head 1A, the breathable sheet 2 is placed on the bottom surface 19A of the recess 19 so that the front opening 7 of the tip end surface is directed downward and the openings 7 are respectively marked. It is fitted in the recessed portion 19 of the pedestal 18 in the mounted state (the front surface of the case is placed on the breathable sheet). At this time, the magnetic head 1A is pressed against the pedestal 18. That is, the cradle 1
Since 8 is an elastic resin and the lateral width U of the concave portion 19 is set to be slightly smaller than the lateral width V of the case 6, by forcibly inserting the magnetic head 1A into the concave portion 19, the front surface of the case 6 and the ventilation can be improved. The bottom surface 19A of the recessed portion 19
It can be pressed firmly against and is kept in close contact (lifting after fitting the case can be prevented). The presence of the second recess 20 is also effective in avoiding the head core 8 and the dummy block 25, which are the protrusions on the front surface of the case, and closely contacting the bottom surface 19A of the recess on the pedestal side on the front surface of the case. As described above, it is important to maintain the close contact with the bottom surface 19A of the recess on the pedestal side through the breathable sheet 2 and to maintain the close contact in order to prevent resin leakage during resin filling in a later step. Is.

Then, as shown in FIG. 4, an epoxy resin 14 is injected into the space 13 inside the case 6 and cured by heating.
In this case, since the adhesion of the front surface of the case to the bottom surface 19A of the recess of the pedestal 18 via the breathable sheet 2 is maintained, a gap that causes resin leakage between the case 6 and the breathable sheet 2. Does not occur. Further, a part of the resin exudes to the breathable sheet 2 through the gap 12 between the front opening 7 and the head core 8, but does not flow out of the breathable sheet 2. Then, the magnetic head 1E sealed and fixed with the epoxy resin 14 is removed from the pedestal 18, the breathable sheet 2 is peeled off, and the magnetic recording medium running surface having the tip end surface of the head core 8 protruding is polished to a smooth surface. As a result, the completed magnetic head 1 shown in FIG. 5 is formed.

The breathable sheet 2 is a mesh cloth,
A non-woven fabric, breathable thin paper, or the like that is easily peeled off after the resin is cured is used.

According to the configuration of the above embodiment, when resin is cast in the case, the front opening of the case is sealed with a breathable sheet to perform resin casting of the space in the case once. The above resin molding is sufficient, and various improvements can be achieved as compared with the conventional manufacturing method using the two-time molding method.
That is, even if the resin is injected by sealing the front opening of the case with a breathable sheet, the resin does not flow out to the outside of the case until it is cured. The space can be sealed, and the occurrence of defects due to resin leakage can be suppressed. For this reason, the resin kneading work and the equipment such as a dryer, which has been required twice for the conventional manufacturing method, can be completed once, the man-hour and the working time can be reduced by half, and the amount of the resin used can be reduced by eliminating the waste of the resin used. Further, since the amount of the resin that flows out from the front opening and projects to the front end surface of the case and hardens is small compared to the conventional manufacturing method, it is possible to shorten the working time in the polishing process of the running surface of the magnetic recording medium.

An inorganic filler such as silica may be added to the epoxy resin in order to improve wear resistance.

[0017]

As described above, according to the method of manufacturing a magnetic head of the present invention, resin casting is performed in a state where the front opening of the case of the magnetic head is covered with a breathable sheet to prevent the resin from flowing out. By doing so, it is possible to perform resin casting once, and it is possible to reduce the man-hours and work time as compared to the case of the double molding method by the conventional manufacturing method, and save the amount of resin used. However, the cost of the product can be reduced.

[Brief description of drawings]

FIG. 1 is an exploded view showing a magnetic head before resin casting, a breathable sheet and a pedestal in an embodiment of a method of manufacturing a magnetic head according to the present invention.

FIG. 2 is a cross-sectional view showing a state in which a magnetic head before resin casting is mounted on a pedestal.

FIG. 3 is a vertical sectional view of the same.

FIG. 4 is a cross-sectional view showing a resin filling step in the example.

FIG. 5 is a cross-sectional view showing a completed magnetic head in an example.

FIG. 6 is a cross-sectional view showing a first resin injection curing step in the conventional method of manufacturing a magnetic head.

FIG. 7 is a cross-sectional view after resin curing in the same process.

FIG. 8 is a cross-sectional view showing a second resin injection curing step in the conventional method of manufacturing a magnetic head.

FIG. 9 is a cross-sectional view showing a completed magnetic head in a conventional magnetic head manufacturing method.

FIG. 10 is a front view showing a completed magnetic head in a conventional magnetic head manufacturing method and the present invention manufacturing method.

[Explanation of symbols]

 1 Magnetic Head 2 Breathable Sheet 4 Recording / Reproducing Gap 5 Recording / Reproducing Head 6 Case 7 Front Opening 8 Head Core 12 Gap 13 Space 14 Epoxy Resin 16 Holder 18 Catch 19 First Recess 20 Second Recess

Claims (5)

[Claims] 1. A state in which a head core is exposed to a front opening of a case and the front opening is covered with a breathable sheet,
A method of manufacturing a magnetic head, characterized in that the space in the case is filled by resin casting once. 2. The breathable sheet is placed on the recessed surface of a pedestal having a first recess formed as a bottom surface having a recessed surface substantially matching the curved surface of the front surface of the case, and the head core is placed on the breathable sheet. 2. The method of manufacturing a magnetic head according to claim 1, wherein the cases having the marks are stacked and placed to seal the front opening. 3. The method of manufacturing a magnetic head according to claim 2, wherein the pedestal is made of an elastic resin that is non-adhesive to the resin. 4. The method of manufacturing a magnetic head according to claim 3, wherein the width of the first recess is set to be smaller than the width of the case before the case is placed. 5. The method of manufacturing a magnetic head according to claim 2, wherein a second recess for avoiding the head core and the dummy block portion protruding from the front surface of the case is formed on the bottom surface of the first recess.