JPH0714113A - Magnetic head - Google Patents

Abstract

PURPOSE:To enhance the strength of a magnetic head to mechanical working by using a transparent crystallized glass as seal bonding glass for a pair of cores. CONSTITUTION:Rodlike seal bonding glasses 4, 5 are poured into a groove 3 in the middle of cores 1, 2 to integrate the cores 1, 2. The front glass 4 seal bonding the gap face sides is a transparent crystallized glass and the back glass 5 may be amorphous. For example, glass consisting of, by weight, 50.4% SiO2, 22.77% ZnO, 12.54% Li2O and 14.26% Al2O3 is used as seal bonding glass and a magnetic head is assembled at 650 deg.C working temp. for seal bonding. The rate of cracking is remarkably reduced to 10% as compared with 30-40% in the case of use of a conventional uncrystallized zinc borosilicate glass.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a video tape and a DA.
The present invention relates to improvement of a magnetic head in a magnetic recording and / or reproducing apparatus using a magnetic recording medium such as a T, floppy disk, hard disk, audio tape, magnetic card.

[0002]

2. Description of the Related Art FIG. 2 shows a typical structure of a VTR head using ferrite as a core material. In this head, core materials 11 and 12 are opposed to each other at an interval equal to the gap width, and the gap is filled with a gap glass 13,
They are joined by the sealing glass 14, and finally, a coil (not shown) is wound by utilizing the groove 15. Gap glass is generally SiO ₂ or Pyrex (trade name)
A material such as glass that does not easily react with ferrite even at high temperatures is used, and as a result, a head having a narrow gap width is stably obtained.

[0003]

As the sealing glass, when the core material is ferrite, the working temperature is widely used at about 750 ° C., but it contains PbO or an alkaline component in order to lower the melting point. ing. Therefore, its strength is weaker than that of the high melting point gap glass. Further, in the metal-in-gap (MIG) head in which the thin films 16 and 17 of the alloy magnetic material having high magnetic permeability are formed on the ferrite core materials 11 and 12 as shown in FIG. 3, the heat resistance of the magnetic material is not high. Therefore, a sealing glass having a working temperature of 600 ° C. or lower tends to be used. Since such a glass contains more components for lowering the melting point, it has a very weak strength and reduces the productivity of the head.

[0004]

In order to solve the above problems, the present invention uses a transparent crystallized glass as a sealing glass.

[0005]

[Operation] Crystallized glass is 2 to 5 times stronger than uncrystallized glass. Generally, glass loses transparency when crystallized, but it is transparent when the crystal is shorter than the wavelength of visible light. The reason why the transparent crystallized glass is used in the present invention is to make it easy to adjust the gap depth (shown by d in FIG. 1) to a predetermined value. Gap depth is
One of the factors that determines the magnetic characteristics of the head, the shallower the head characteristics are improved, the conversely the head life due to wear is shortened. Therefore, it is necessary to adjust the optimum value taking both factors into consideration. With the structure of the present invention, the mechanical strength of the magnetic head is improved, and as a result, the productivity is improved.

[0006]

EXAMPLE An example of the present invention will be described below with reference to FIG. The following embodiments are examples embodying the present invention and are not of the nature to limit the technical scope of the present invention. FIG. 1 shows a step of pouring a rod-shaped sealing glass into a glass groove 3 in the middle of the cores 1 and 2 to integrate the cores. Here, the sealing glass is shown as two pieces of the front glass 4 and the back glass 5, but the front glass may be omitted depending on the volume of the back glass. Also, in the figure, the front glass 4
Although it is arranged in the groove 6 of the core 2, it may be press-fitted from the lower surface side in the drawing which is the tape sliding surface. The front glass 4 for sealing the gap surface side is a transparent crystallized glass, and the back glass 5
May be amorphous glass. However, when the front glass is not used, the back glass is transparent crystallized glass. The core integrated with the sealing glass is cut into a predetermined thickness to form a head chip. At this time, if the glass is weak, cracks occur in the glass and the processing yield decreases. In the following examples, the crack occurrence rate when cutting into chips was examined.

Example 1 As a sealing glass, SiO ₂ = 50.43%, ZnO = 22.77%, Li ₂ by weight%
A magnetic head was assembled as shown in FIG. 1 by using glass with O = 12.54% and A1 ₂ O ₃ = 14.26%. The working temperature for sealing was 650 ° C. The crystal phase of the glass was β eucryptite, but was transparent. The crack occurrence rate was 11%.

[Example 2] As a sealing glass, SiO ₂ = 34.03%, P ₂ O ₅ = 16.21%, Mg by weight%.
O = 4.58%, CaO = 44.68%, CaF ₂ =
A magnetic head was assembled as in FIG. 1 using 0.5% glass. The working temperature was 650 ° C. The crystal phase of glass was apatite but was transparent. The crack occurrence rate was 13%.

[Example 3] A MIG head (Fig. 3) in which a cobalt (Co-Nb-Zr-Ta) amorphous magnetic material was thinned on a ferrite core material was assembled. As sealing glass, TeO ₂ = 70% and TiO ₂ = 15 in mol%
%, BaO = 15% glass was used. Working temperature is 4
It was 50 ° C. The crystal phase of glass was barium titanate, but was transparent. The crack occurrence rate was 10%.

Comparative Example 1 As a comparison between Examples 1 and 2, non-crystallized zinc borosilicate glass (Nippon Electric Glass FH
A head was assembled in the same manner except that No. 11) was used. The crack occurrence rate was 30%. [Comparative Example 2] As a comparison with Example 3, a head was assembled in the same manner except that lead borosilicate glass (T015, manufactured by Iwaki Glass) that did not crystallize was used. Crack occurrence rate is 4
It was 0%.

[0011]

As described above, according to the present invention, the processing yield of the magnetic head can be greatly improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a step of integrating a core with a sealing glass in an example of the present invention.

FIG. 2A is a perspective view showing a typical structure of a magnetic head using a ferrite core. FIG. 3B is a plan view of a main part of the magnetic head.

FIG. 3A is a perspective view showing a typical structure of a magnetic head using a ferrite core formed with an amorphous thin film. FIG. 3B is a plan view of a main part of the magnetic head.

[Explanation of symbols]

 1, 2 Core 3 Glass groove 4, 5 Sealing glass d Gap depth

Claims (1)

[Claims] 1. A magnetic head comprising a pair of cores and a sealing glass connecting the cores, wherein at least the sealing glass on the gap side is a transparent crystallized glass.