JPS5827566B2 - Multi-element magnetic head and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic head suitable for use in audio cassette tape decks, etc. More specifically, the present invention relates to a magnetic head suitable for use in audio cassette tape decks, etc. A multi-element magnetic head is a so-called recording/playback combination head (
(hereinafter referred to as R&P combination head).

Technical problems in designing and manufacturing this type of R&P combination head include crossfeed, that is, leakage of magnetic flux from the recording head element to the reproduction head element, and the parallelism of the recording gap and the reproduction gap.

The present applicant has developed an R&P combination head as shown in FIGS. 1 and 2 as an R&P combination head that solves problems such as crossfeed and gap parallelism.

The structure will be explained below based on the drawings.

In FIGS. 1 and 2, reference numeral 10 indicates a recording head element, and the head element includes recording cores 11, 11 made of ferrite.

The head cores 11, 11 have a front core 11L111 formed by caps 113, 113, and a coil 114.1.
14 and a rear core 112 and a rear core 112 and 112 formed by winding a core 14, and these cores are held by a core holder 12.

13 is a channel shield plate interposed between the Heradokotsu 11, 11, 14 is a triple shield tube made of permalloy that houses these recording parts, 15 is a cylindrical shield case that further houses it, 16° Reference numeral 16 denotes a dummy core made of ferrite and inserted into a space formed by the shield tube 14 and the helad cores 11, 11.

Reference numeral 20 indicates a reproducing head element, and the head element includes reproducing rad cores 21, 21 made of ferrite.

The head cores 21, 21 have a front core 211, 211 formed with a gap 213, 213, a coil 214,
214, and a rear core 212 and a rear core 212 formed by winding a core 214, and these cores are held by a core holder 22.

23 is a shield plate for the channel interposed between the head cores 21 and 21, 24 is a triple shield tube made of permalloy that houses these parts for reproduction, 25 is a cylindrical shield case that further houses the threads, 26゜26 is a dummy core made of ferrite inserted into a space formed by the shield tube 24 and the helad core 2L21.

30 is a cylindrical shield case that houses the cases 15 and 25.

Here, the gap interval (dimension) 11 between the recording gap 113 and the reproduction gap 213 is set to 3.4 mm.

The breakdown of this 3.4 mm is that the width dimensions 12 and 13 of the recording core 11 and the playback core 21 are 0, respectively.
．． 7 mm, the space for intervening the shield tubes 14, 24 and the shield cases 15, 25 is between 1.0 mm, the space for intervening the head core holders 12, 22, the shield tubes 14, 24, and the herad core 11. , 21, the total space for both recording and playback sides is 0.5 inches.

Next, a method of determining the parallelism of the gap of the head, that is, a manufacturing method thereof, will be explained based on the manufacturing process diagram shown in FIG. 3.

First, as shown in Figure 3a, three helad core materials 100.2
00.300 are prepared and bonded (glass welded) as shown in the figure to form one front core block.

As a result, a recording gap 113 and a reproduction gap 213 are formed.

Next, the sliding surface side of the tape is cut into a predetermined shape, for example, a W shape as shown in FIG. Material 4
00 is adhered as shown in FIG. 3C.

Next, a groove 301 for inserting a shield case covering a part of the non-magnetic material 400 is formed in the head core material 300 as shown in FIG. At the same time, the front core block is sliced into chips as shown in FIG. 3e to form front cores 111, 111, 211, and 211.

Here, the parallelism of the gaps 113 and 213 is determined by the non-magnetic material 40.
It is held at 0.

Next, as shown in FIG. 3f, the coils 114, 114, 214
, 214 wound around the rear core 112, 112, 212,
212 to the front cores 111, 111, 21 as shown in the figure.
L211, and then the shield cases 15 and 25 are inserted as shown in the third diagram of Fig. 3g1 and fixed with resin.

Afterwards, the tape sliding surface is finished by cylindrical grinding to complete the process.

At this time, the non-magnetic material 400 is separated for recording and reproduction, but since the head element body is fixed by the shield cases 15 and 25, the parallelism of the gap does not change.

By the way, recording with an R&P combination head
In order to achieve good playback, that is, to suppress level fluctuations, it is important to make both the recording gap 113 and the playback gap 213 in close contact with the cassette tape 40, and one way to fully satisfy this is to use the head core 11 described above.
, 21 may be made thinner to reduce the gap distance z1 between the two gaps.

However, if the gap interval 11 is narrowed in the R&P combination head described above, level fluctuations can be suppressed, but on the other hand, there arises the problem of worsening crossfeed.

Furthermore, the aforementioned R&P combination head has the disadvantage of being weak against external guidance.

In view of the above points, the present applicant further developed an R&P combination head as shown in FIGS. 4, 5, and 6.

That is, the shield cases 17 and 27 are formed into a U shape by drawing, and the shield cases also cover the tape sliding surface.

According to such a shield structure, the thickness of the shield cases 17 and 2γ (between 0 and 2) is reduced to 1/2 compared to the thickness of the conventional shield cases 15 and 25 (0.5 mm), taking cross-feed into consideration. As a result, the gap interval 11 between the recording gap 113 and the reproduction gap 213 can be narrowed, and level fluctuations can be improved.

Also, since the tape sliding surface is also shielded by a shield case, it has a strong feature against external induction.

However, in such an R&P combination head, it is not possible to hold the recording/playback head element in the front part of the head core with a non-magnetic material in the manufacturing process mentioned above, and the manufacturing process, especially the parallelism of both the recording and playback gaps, is difficult. It took a lot of effort.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks, provide an R&P combination head that is resistant to external induction, has little crossfeed, and has no azimuth loss due to the parallelism of the gap, and a method for manufacturing the same.

Embodiments of the present invention will be described below based on the drawings.

FIG. 4 is a front view of an R&P combination head showing one embodiment of the present invention applied to a stereo cassette magnetic head, FIG. 5 is a vertical cross-sectional view of the main part thereof, and FIG. 6 is a cross-sectional view of the main part thereof.

In this figure, the same parts as in FIGS. 1 and 2 are given the same numbers, and detailed explanation thereof will be omitted.

Reference numerals 17 and 27 indicate a shield case that accommodates the herad cores 11 and 21, respectively, and the shield case is formed into a U shape by drawing.

The shield cases 17 and 27 are joined together as shown, and windows 171 and 271 are formed on the tape sliding surfaces to expose a portion of the helad core 11 and 21.

50 indicates a plasma film (ceramic material made of titanium oxide) deposited by plasma spraying on the tape sliding surface of the shield case 1γ, 27, and this plasma film is for improving the wear resistance of the tape sliding surface. It is.

60 is Herad core 11゜21 front core 111,1
11, 211° 211 shows a non-magnetic material (for example, glass or non-magnetic ferrite) bonded to the rear surface, and the non-magnetic material has a groove 63 for inserting the joint piece of the shield case 17, 27, a coil 114, Grooves 61 and 62 are formed to escape contact with the non-magnetic material 60 of 214.

Here, the grooves 61 and 62 are spaces for winding the coils 114° and 214 around the rear cores 112 and 212, so if both the rear cores 112 and 212 are L-shaped, the grooves 61 and 62 will not exist. Good too.

In such an R&P combination head, the thickness of the shield cases 17 and 27 is set to 0.2 mm, making it possible to narrow the recording/playback gap 11.

Specifically, we succeeded in reducing the gap distance 11 to 1.4 degrees by improving the shape of the front core.

Next, a method for manufacturing the above-mentioned R&P combination head of the present invention will be explained.

FIG. 1 is a process diagram showing the manufacturing process of the R&P combination head of the present invention.

First, as shown in Figure 7a, three rectangular herad core materials 1
00, 200, and 300 are prepared and bonded (glass welded) as shown in the figure to form one front core block.

As a result, a recording gap 113 and a reproduction gap 213 are formed.

Next, it is sliced along the two-dot chain line in FIG. 7a, and magnetic recording and reproduction are made independent as shown in FIG.

Next, as shown in FIG. 7C, a non-magnetic material 600 having grooves 601, 602, 603 is adhered to the rear surface of the front core block as shown.

Here, the nonmagnetic material 600 may have a shape as shown in FIG.

Next, the tape sliding surface side of the front core block is cut into a predetermined shape, for example, a W shape as shown in FIG.
A shield case insertion groove 301 leading to the shield case insertion groove 301 is formed.

Next, slice along the two-dot chain line in Figure 7d, and
Front core 111.111.211.21 as shown in
1 and a nonmagnetic material 60 are formed.

Here, the parallelism of the gap 113°213 is the non-magnetic material 60
This is maintained until the final process.

Next, the upper and lower surfaces of the front core 111.111.211.211 and the non-magnetic material 60 are wrapped, and the coils 114, 114, 21 are formed on the wrapped surfaces as shown in FIG. 7f.
Rear core 112, 112, 212 wound with 4°214
212 to complete the head element.

Here, the shape of the rear cores 112, 112, 212, 212 may be as shown in FIGS. 9 and 10.

In the rear core shape shown in FIG. 9, the non-magnetic material 60 has grooves 6L62.
In the rear core shape shown in Fig. 10, grooves 61 and 62 are required.
is not required.

Next, the shield cases 17 and 27 are placed in front of the head element as shown in FIG. 7g and fixed.

Next, the front surfaces of the shield cases 17 and 27 are subjected to plasma spraying, and the plasma film 50 welded by the spraying and the tip of the front core 111.11L21L211 are cylindrically ground to finish the tape sliding surface.

Note that 131 and 231 are grooves for inserting channel shield plates.

FIG. 11 shows another embodiment of the present invention, in which the front cores 111 and 211 are connected to two core pieces 111a and 111b forming gaps 113 and 213.
and 211a, 211b, and one core piece 111
It is composed of core pieces 111c and 211c adhered to the inner surfaces of core pieces 111c and 211b as shown in the figure, and has a gap interval of 1.
1 is 1.4.

The breakdown of this 1.47nr/L is shield case 17,2
The plate thickness of 4 is 0.2 mm x 2, and the core pieces 111b and 211
Dimensions 14 and 15 of b are 0.4 mm x 2, case 17,
27 and core piece 111b.

The space of 211b is 0.1 mm×2.

The dimensions 16 and 17 of the core pieces 111c and 211c are 0.3m.
m, X2.

Next, a method for manufacturing such an R&P combination head will be explained based on FIG. 12.

First, as shown in Fig. 12a, three rectangular head core materials 100°, 200, and 300 are prepared, and an inclined groove 101°2 is formed on one side of two of the head core materials 100 and 200.
01 and then combine them with the remaining Herad core material 30
For example, glass is bonded to the front core block as shown in FIG. 12a to form one front core block.

As a result, a recording head gap 113 and a reproduction gap 213 are formed.

Next, the grooves 102 and 20 are sliced along the two-dot chain line in FIG.
2, magnetically recording and playing independently.

The following steps are completed following the steps shown in FIG. 7C to FIG. 1G.

According to such an R&P combination head, FIG.
It is possible to obtain recording/reproducing efficiency approximately equivalent to that of the R&P combination head shown in FIG.

This is the core piece 111b of the front core 111, 211,
Although the dimensions 14 and 15 of the core pieces 111b and 211b are smaller than those of the conventional R&P combination head, the core pieces 111b and 2
Core piece 111C on the side of 11b.

211c is provided to increase the abutment area between the front cores 111, 211 and the rear cores 112, 212, and the core pieces 111c, 211c are formed into elongated shapes extending in the direction of the gaps 113 and 213 to prevent the magnetic resistance of the cores from increasing. This is because.

It was also confirmed that the level fluctuation could be improved.

Specifically, when we measured level fluctuations for high frequencies (IOKHz), according to the conventional R&P combination head, it was 2 to 3 dB, but according to the present invention, it was 1 dB.
I was able to keep it below B.

This is based on the fact that the gap interval 11 between the recording gap 113 and the reproduction gap 213 is made smaller.

According to the present invention described above, the gap parallelism of recording and playback is maintained by the non-magnetic material until it reaches the final head process, so it is possible to create an R&P combination head with no azimuth loss. It is now possible to make the shape into a squeeze type, and it is possible to provide a multi-element head that is resistant to external induction and has little cross-feed.

[Brief explanation of the drawing]

Fig. 1 is a front view of a conventional R&P combination head, Fig. 2 is a cross-sectional view of its main parts, Fig. 3 is a process diagram showing the manufacturing process of the conventional R&P combination head, and Fig. 4 is a diagram showing the manufacturing process of the conventional R&P combination head. A front view of an R&P combination head showing an embodiment, FIG. 5 is a cross-sectional view of its main parts, FIG. 6 is a longitudinal cross-sectional view of its main parts, and FIG. 7 is a R&P combination head of the present invention.
FIG. 8 is a perspective view showing another embodiment of the non-magnetic material of the present invention, and FIGS. 9 and 10 are perspective views showing other embodiments of the rear core of the present invention. , 11th
The figure is a sectional view of a main part of an R&P combination head showing another embodiment of the present invention, and FIG. 12 is a perspective view showing a part of the manufacturing process thereof. 10... Recording head element, 11...
Head core for recording, 20...Head element for playback, 21...Head core for playback, 111,211
...Front core, 112,212...
・Rear core, 17, 27...shield case,
60...Nonmagnetic material.

Claims (1)

[Claims] 1. In a multi-element magnetic head in which two head elements with different recording and playback functions are arranged on the same track, the magnetic core forming the magnetic circuit of each head element is used for recording. Alternatively, the front core part for recording and playback can be connected by dividing it into a front core part with a gap for playback and a rear core part made by winding a coil, and joining a non-magnetic material to the rear of the front core. A multi-element magnetic head characterized by: 2. The multi-element magnetic head described in Patent No. 1, characterized in that the thickness of the front core and the thickness of the non-magnetic material are the same. 3. In a method of manufacturing a multi-element magnetic head in which two head elements with different recording and playback functions are arranged on the same track, a non-magnetic A process of gluing the materials, a process of dividing the front block into front cores for recording and playback, a process of slicing the front block into front chips, and a process of butting the rear core with a coil wound around the sliced surface of the front chip. A method for manufacturing a multi-element magnetic head, which includes a step of covering the tape with two shield cases, and a step of finishing the tape sliding surface by polishing.