JPS60145514A - Magnetic head - Google Patents

Abstract

PURPOSE:To obtain a highly reliable magnetic head having stable characteristics without having uneven wear, etc. by forming gap material layers and adhesive glass layers within a specified thickness range on the respective gap surfaces of a pair of magnetic core halves then butt-joining both core halves. CONSTITUTION:Gap material layers 5 consisting of non-magnetic materials such as SiO2 having hardness, stability and wear resistance are formed by vapor deposition, etc. on the respective gap surfaces 4a of a pair of magnetic materials 4, 4. Adhesive glass layers 6 consisting preferably of 60-90wt% PbO and consisting of the balance SiO2, Al2O3, B2O3, etc. are then stuck to 50-500Angstrom thickness on the layers 5. Both magnetic materials 4, 4 are butted and are pressed and heated as shown by arrows 7 to fuse the layers 6 to each other. A gap is thus formed in such a way that the total thickness of the layers 6 attains 100- 1,000Angstrom . The uneven wear is thereby prevented and the head having stable characteristics without deterioration in the quality of a video image is obtd.

Description

[Detailed description of the invention] Industrial applications This invention relates to a magnetic henode.

Conventional Structures and Their Problems Generally, a magnetic head has a magnetic gear, and the accuracy of this magnetic gap has a significant effect on the characteristics of the magnetic head, as is well known. As shown in FIG. 1, the magnetic gap of the magnetic head is composed of a high permeability magnetic material 1 and a non-magnetic material 2 which is filled in this gap and serves as a gap material. The material 2 was mainly 5i02 or high melting point glass due to its wear resistance and hardness.

However, 5i02 had the drawback of poor reliability because the pins held between the magnetic bodies 1 on both sides were not bonded at the gap surfaces.

On the other hand, high melting point glass must be treated at a relatively high temperature of 700°C to 900°C to ensure good adhesion.
This has the disadvantage of promoting diffusion into the ferrite surface layer of glass, thereby widening the effective width of the magnetic gap and deteriorating the magnetic properties.

On the other hand, when an amorphous magnetic alloy is used for the magnetic body 1, there is a problem with the crystallization temperature of the material, and there is a restriction that it cannot be heated above 500° C. from the viewpoint of the magnetic henodic material.

OBJECTS OF THE INVENTION It is an object of the present invention to solve the above-mentioned disadvantages and to provide a magnetic head having a highly reliable gap structure.

Structure of the Invention This invention forms a gap material layer on the gap surface of a half-closed magnetic core, and an adhesive glass layer is placed between the gear material layers.
It is characterized by being formed with a thickness of 1,000 people. Because of this Q, the reliability of the gap material layer can be maintained at 6' (C), and by setting the thickness of the adhesive glass layer as described above, it is possible to provide a highly reliable magnetic head as described later.

DESCRIPTION OF THE EMBODIMENTS One embodiment of the present invention is shown in FIGS. 2 through 8. That is, FIGS. 2 and 3 show configuration diagrams. 5i02 as the gap material layer 5 on the gap surface 4a of the magnetic body 4
A glass layer 6 with a low melting point is attached for the purpose of adhesion, and the same cores are placed facing each other and heated while applying the force of the arrow 7 in Fig. 3. By doing so, the glass layer 6 is fused. Furthermore, as a result of examining various dimensions and various gear material layers 5 and adhesive glass layers 6, the present inventors found that the gap can be reliably changed only within a certain thickness range of the adhesive glass layer 6. Ta.

4 to 6 show manufacturing examples. As shown in FIG. 4, Co-Nb-
Targeting Zr (weight ratio: 81:1326), a core block made of an amorphous 'ft&i alloy was produced by spucking, and after processing the winding groove 10, the magnetic gap surface 11 was mirror-finished. Process it into Next, as shown in FIG. 5, a gap material layer 12 of 5i02 is sputtered on the magnetic gap surface 11 by RF sputtering, and a commercially available lead-based low melting point glass (PbO: 84%, B2O
3:11%, 5i02:3%, Al2O2:2% (all % by weight, softening temperature about 350° C.) layer 13 was formed to obtain a half-dead head core block. As shown in FIG. 6, these half-core blocks A and B are butted together as a pair, and a separately prepared low-melting point adhesive glass rod 14 is placed and heated to separate the left and right half-core blocks A and B. Join. The working temperature at this time is 480°C. The head was completed by cutting out a head from the magnetic core obtained in this way.

Next, various thicknesses of the gap material 5j02 and the low melting point glass used for adhesion were varied. First, the gap length is approximately 5i when there is no low melting point glass as an adhesive layer, that is, when only 5i02 is used as a spacer.
02 thickness - gap length. However, as mentioned above, in the gear of only 5i02, the gap surface 11 has no adhesive layer, so the winding window 1
Since it is bonded only with the low melting point adhesive glass layer 13 at the tip of the core block (commonly called the apex part), its strength is weak, and during the process of slicing it into pieces, the left and right core blocks A and B are separated. It was found that the yield of heads was very poor, such as peeling or cranking of the glass 14 in the apex portion during tape running, resulting in widening of the gap. From this, it is clear that the adhesive glass layer in the gap is indispensable.

Figure 7 shows the thickness of the low-melting glass that is the adhesive glass layer 13 in the gap (thickness of the sputtered film) and the value obtained by subtracting the SiO2 thickness from the gap length measured from the actually completed head, that is, the thickness of the glass in the gap. It shows the thickness ratio of low melting point glass. As is clear from this figure, there is an i direction in which the gap length varies as the thickness of the low-melting glass in the gap increases, and if the sputtered thickness does not change, the 45-degree angle shown by the broken line in Figure 7 It is a straight line, but the slope is gentler than that straight line. This means that the low melting point glass in the gap part is softened and fluidized by heating while pushing the left and right core blocks A and B. Also glass layer 1
The thicker the thickness of 3, the more difficult it is to control.

In addition, various heads with different thicknesses of low-melting glass in the gap were attached to a video tape recorder as rotating heads, and a commercially available metal tape was run.The relative tape speed of the head was 3.5 m/sec. The level difference (uneven wear) between the amorphous magnetic material 9 on the sliding surface and the gap portion was measured. In other words, while the tape is running, the gap part falls down compared to the magnetic material, and the level difference is caused by the gear material 5i.
02, but is caused by the low melting point glass that is the adhesive glass layer 13 in the gap part, and as a result, chipping and sagging of the gap edges occur, and the effective gap widens due to the so-called gap part cracking, which causes problems in the high frequency range. This is because it causes a decrease in head output. Figure 8 shows uneven wear and 5MHz for the value obtained by subtracting the thickness of 5i02 from the gear tooth length.
The relationship between head relative output is shown below.

Combining the above results, the central adhesive glass layer 13 and the gap 44 layers on both sides constitute a magnetic gear, and the thickness of the central adhesive glass layer 13 is tfc100 people ≦t
It is clear that by setting the number of people to ≦1000, a magnetic head with extremely high reliability and small variation in gap length can be obtained.

That is, the lower limit of the thickness t was limited to 100 people because, although it is desirable that t be as small as possible in terms of gear accuracy and variation, if it is too small, the yield will deteriorate as described above. In addition, with current processing technology, it is difficult to process the gap surface with a surface roughness of less than 50 people at most, and considering the need to absorb this surface roughness, it takes 50 people to process the core block on one side, or 100 people as the head. is the limit.

The upper limit is set at 1,000 because during tape running, uneven wear occurs in the gap portion, causing the effective gear knob to widen, resulting in a decrease in head output as shown in FIG.

For example, in signal processing of video images in the high frequency region, if the output is reduced by 3 dB or more, the image quality will be significantly degraded, and if it is 1000 Å or more, the variation in gap length will become large, making it impractical.

According to this invention, since t is preferably in the range of 100 people≦L≦1000 people, the thickness of t and the thickness of 5i02 are selected at the desired gap length. In addition, in the example, an amorphous alloy made of Suba-Ivy was described, but
The same applies not only to sputtered materials but also to ultra-quenched ribbon amorphous materials.

In addition, if the amount of PbO in the composition of the adhesive glass layer is 90% or more, the glass becomes unstable and tends to devitrify. On the other hand, if the amount of PbO is 60% or less, no fusion with the gap material is observed. However, when the core block is cut into individual chips, there are problems such as breakage. Also, 5102 is currently the best gap material in terms of hardness and stability.

Other non-magnetic ceramics if wear resistant, e.g. A'
12203, Z r O2, T i O2, titanium f
Even barium, forsterite, etc., have no problem in the negative direction.

Effects of the Invention As described above, according to the present invention, the characteristics are stable and high reliability can be ensured.

[Brief explanation of the drawing]

FIG. 1 is a partial plan view of a conventional example, FIG. 2 is a plan view of a core block half-closed state before adhesion, showing the configuration of an embodiment of the present invention, and FIG. 3 is a plan view of a core block half-closed state in a bonded state. ,
Figure 4 is a perspective view of a magnetic head manufacturing example before the gear hub is attached to the core block half-closed, Figure 5 is a perspective view after gap material is attached, Figure 6 is a front view of the bonded state, and Figure 7 is the low melting point glass. FIG. 8 is a relationship diagram of (gap length - thickness of 3jO2) with respect to the thickness of , and FIG. 8 is a relationship diagram of uneven wear and head relative output with respect to (gear tooth length - thickness of 3i02). A, B...Core block half-closed, 12...Cap material layer, 13...Glass layer for adhesive Fig. 7 o 1000 2000 (Cap length - 5i02 h) (in) Fig. 8

Claims (3)

[Claims] (1) A pair of magnetic core halves having a gap surface forming a magnetic gap, a gear material layer formed on the gap surface, and a gear material layer with a thickness of 100 to 1000 mm interposed between these 2144 layers. Magnetic head with adhesive glass layer and in the range of people. (2) The adhesive glass layer contains 60 to 90% by weight of I
) b O, and the remainder is 5i02, A j!
203. 8203 or the like, according to claim (1). (3) The magnetic head according to claim (1), wherein the magnetic core half-hole is made of an amorphous magnetic alloy.