JPH0467247B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic head, particularly a magnetic head for a VTR or the like.

BACKGROUND TECHNOLOGY AND PROBLEMS In recent years, with the development of magnetic recording technology, magnetic heads for VTRs have become capable of recording and reproducing magnetic tapes with high magnetic flux density and high coercive force. In order to improve the recording density, it is required to make the track as narrow as possible. In order to meet this demand, as shown in Fig. 1, a magnetic head of a type in which a metal magnetic thin film 2 made of sendust, amorphous alloy, etc. is sandwiched from both sides by composite plates 5, 5' made of non-magnetic ceramic 3 and ferrite 4 is used. 1 is used. As described above, high hardness ceramic is used as the non-magnetic ceramic disposed in the tape sliding portion of the magnetic head from the viewpoint of wear resistance. However, the metal magnetic thin film 2 is made of wear-resistant materials 3 such as sapphire, foosterite, Zn-ferrite, magnesia, beryllia, etc.
As shown in FIG.
will cause preferential wear. Metallic magnetic materials are inherently more abrasive than oxide ferromagnetic materials, and usually create a step on the surface when sliding with the tape.

When a step is created on the tape sliding surface in this manner, a gap is formed between the tape and the metal magnetic thin film core at the gap portion, and the reproduction output of the head is significantly reduced due to so-called spacing loss. To solve this problem, if a non-magnetic guard material is used that does not create a step on the tape sliding surface in order to prevent spacing loss, the guard material itself will wear out significantly, which will shorten the life of the magnetic head. be.

Purpose of the Invention In view of the above, the present invention prevents the occurrence of a level difference between the metal magnetic thin film and the non-magnetic material sandwiching it in the gap portion of the tape sliding surface, and also provides a magnetic material with excellent wear resistance. It provides a head.

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention has been developed by bonding a metal ferromagnetic thin film, a ferromagnetic oxide, and a nonmagnetic material to form a magnetic gap with the metal magnetic thin film, and forming a metal magnetic thin film on a surface facing a magnetic recording medium. In a magnetic head in which a magnetic head and a non-magnetic material coexist, the non-magnetic material near the magnetic gap is made of a non-magnetic material that has lower wear resistance than the non-magnetic material in other parts.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIG. 3 and subsequent figures.

FIG. 3 is a perspective view of an example of a magnetic head according to the present invention. This magnetic head 11 has a metal ferromagnetic thin film 12 made of sendust, amorphous alloy, etc., covered with a highly wear-resistant nonmagnetic material such as nonmagnetic ceramic 13 from both sides.
and composite guard plates 15 and 15' made of a metal magnetic oxide such as ferrite 14,
Tape sliding portion 1 of this composite guard plate 15, 15'
5a, 15a', non-magnetic ceramic 13,
The vicinity of the magnetic gap g of 13 is made of a non-magnetic material with low wear resistance, such as low melting point glass 16, 16.

By forming the magnetic head 11 in this manner, in the portion away from the magnetic gap g, a metal ferromagnetic thin film 12 and guard plates 15 on both sides,
There is a slight step between the tape sliding parts 15a and 15a' of the metal ferromagnetic thin film 12 and the guard plates 15 and 15' in the vicinity of the magnetic gap g, as shown in FIG. Moving parts 15a, 15
The level difference with a′ almost disappears. That is, guard plate 1
By arranging relatively high wear non-magnetic material such as low melting point glass 16, 16 near the magnetic gap g of the tape sliding portions 15a, 15a' of tape T, its own hardness allows it to As shown in Figure 6, as the low melting point glass parts 16, 16 wear, the tape sliding parts 15a, 15a' become curved, and the impact and friction on the surface of the metal ferromagnetic thin film 12, that is, on the tape sliding surface, decreases. . On the other hand, low melting point glass part 1
6, 16, i.e. non-magnetic ceramic 13,
13 is hardly abraded and the cross section when in contact with the tape is close to a flat surface as shown in FIG.
Although it causes more impact and friction on the head, it is preferable in terms of head life because it has high wear resistance.

As described above, the magnetic head 11 in this example has a step difference between the guard plates 15, 15' and the metal ferromagnetic thin film 12 in the region away from the magnetic gap g, which has no relation to spacing loss.
The high wear resistance of the magnetic head 15' extends the life of the magnetic head, and the presence of low abrasion resistant non-magnetic materials 16, 16 in the vicinity of the magnetic gap g improves the cross section of the head, that is, the tape sliding surface. As a curved surface, spacing loss is extremely reduced due to impact mitigation due to the tape's inscribed contact with the curved surface.

Next, an example of the manufacturing process of the magnetic head of this embodiment constructed as described above will be explained with reference to FIGS. 8 to 14. First, as shown in FIG _. 8, grooves 13a ₁ , 13a ₂ .
13a ₂ '... is melted and filled with low melting point glass 16, cut into a predetermined width (see Fig. 9), and this composite non-magnetic material of ceramic and glass is formed into a ferrite plate 14 as shown in Fig. 10. After one end surface side of the glass filled portion is matched and joined, a surface polishing process is performed to form a composite guard plate 15. A Sendust thin film 12 is formed on this composite guard plate 15 by sputtering (see FIG. 11), and a composite guard is formed on the surface side of this Sendust thin film 12 as shown in FIG. 12 in the same manner as the composite guard plate 15 of FIG. The plates 15' are joined to form a material 11'. This raw material 11' is cut from the center of the filling part of the low melting point glass parts 16, 16, and one cut surface has a groove 1 for winding.
7 to form a pair of core halves 11a', 11b' (see FIG. 13). This pair of core halves 1
A gear spacer 18 is placed between 1a' and 11b' to connect them (see Fig. 14). Furthermore, by polishing both side surfaces and the tape sliding surface, as shown in FIG. Low wear resistant magnetic material 16,16
A magnetic head 11 is obtained in which the magnetic head 11 is exposed.

In addition, in the above process, both core halves 11a', 1
1b' and which becomes the gear spacer 18, a low abrasion resistant non-magnetic material, that is, a material with a melting point lower than that of the low melting glasses 16, 16, is used for joining the gears 1b' and forming the gear spacer 18.

Further, in the above structure, the grooves 13a ₁ ′, 13a ₂ ′, . . . formed in the non-magnetic ceramic block 13′
By making the thickness of the grooves 13a ₂ ′, 13a ₂ ′, etc. as deep as possible, that is, making the thickness of the bottom of the grooves 13a 2 ′, 13a 2 ′, . The occurrence of a step difference between the ferromagnetic thin film 12 and the guard plates 15, 15' can be suppressed. Therefore, the thickness of the non-magnetic ceramics 13, 13 near the magnetic gap g should be made as thin as possible, and preferably the non-magnetic ceramics 13, 13 should be exposed on the tape sliding parts 15a, 15a' of the guard plates 15, 15'. It is desirable to form it so that it does not.

Further, in the above structure, it goes without saying that the metal ferromagnetic thin film 12 may be a laminate of Sendust thin films or an amorphous alloy laminate with an insulating film interposed therebetween.

The present invention is also effective in a convex metal ferromagnetic thin film/ferrite composite head in which the metal ferromagnetic thin film 12 is exposed only in the vicinity of the magnetic gap g, as shown in FIG. It is also effective in In addition, in FIG. 15, the tape sliding surface portion 15b has the same width as the exposed portion of the metal ferromagnetic thin film 12.
may be formed of ferrite 14.

Effects of the Invention As described above, according to the present invention, in a magnetic head in which a metal ferromagnetic thin film and a non-magnetic guard material coexist on the tape sliding surface, the non-magnetic guard part near the magnetic gap is replaced with a low-wear-resistant non-magnetic guard material. Made of magnetic material, it is possible to minimize the level difference caused by wear on the tape sliding surface as the tape slides near the magnetic gap, resulting in extremely low spacing loss, high wear resistance, and recording/reproducing efficiency. It is possible to obtain a magnetic head with high reliability and high reliability.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a conventional magnetic head, FIG. 2 is an enlarged cross-sectional view of a worn state taken along the line - in FIG. 1, FIG. 3 is a perspective view of an example of a magnetic head according to the present invention, and FIG. 3 is an enlarged sectional view of the worn state taken along the - line in Fig. 3, Fig. 5 is an enlarged sectional view taken along the - line in Fig. 3, Fig. 6 is a sectional view of a portion showing the tape sliding state in Fig. 5, and Fig. 7 is an enlarged sectional view taken along the - line in Fig. 3. Cross-sectional view of the tape sliding state taken along the - line in Figure 3, Figures 8 to 1
FIG. 4 is a perspective view showing the manufacturing process of one example of the magnetic head according to the invention, and FIG. 15 is a perspective view of another example of the magnetic head according to the invention. In the figure, 11 is a magnetic head, 12 is a metal ferromagnetic thin film, 14 is a ferromagnetic oxide part, 13 is a non-magnetic material part, 15 and 15' are composite guard plates, g is a magnetic gap, and 16 is a low-wear non-magnetic material. This is the magnetic material part.

Claims (1)

[Claims] 1. A metal ferromagnetic thin film, a ferromagnetic oxide, and a nonmagnetic material are bonded together, a magnetic gap is formed by the metal ferromagnetic thin film, and the metal ferromagnetic thin film and the nonmagnetic material coexist on the surface facing the magnetic recording medium. 1. A magnetic head comprising: a magnetic head, wherein the non-magnetic material near the magnetic gap is made of a non-magnetic material having lower wear resistance than the non-magnetic material.