JPS6257109A - Magnetic head - Google Patents

Abstract

PURPOSE:To improve the yield over the entire part of a magnetic head by using low melting glass for forming a magnetic gap face and low melting glass for holding said glass in place between magnetic metallic materials in at least the magnetic gap face. CONSTITUTION:This magnetic head is a video head for VTR and for R-DAT formed by using an amorphous magnetic material consisting of Co-Nb-Zn. The amorphous magnetic material 11 consists of reinforcing glass 14 having a high m.p. and bond glass 15 having a low m.p. on both sides thereof near the magnetic gap face 16. The other parts are held in place by a composite material substrate 12 consisting of ferrite 13. Joining of the magnetic gap face 16 is executed by welding of the bond glass 15 which consists of the low melting glass and is provided to the side face of the reinforcing glass 14 consisting of the high melting glass forming part of the magnetic gap face 16.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic head used in a magnetic recording/reproducing device.

BACKGROUND OF THE INVENTION FIG. 4 is a perspective view of a conventional magnetic head, in which an amorphous magnetic material 1 serving as a magnetic core is made of high melting point reinforcing glass 3 near the magnetic gear surface 2, and ferrite 4 is used in other parts. It has a structure in which it is sandwiched between two curved composite material 'R substrates 5. To join the magnetic head at the magnetic gap surface 5, as shown in FIG.
The gap material 5i02 is placed on the magnetic gap surface 5 of 6b.
A layer 7 is formed by sputtering, and one core half 6
Bond glass 8 as a glue material with a low melting point is further formed on a by sputtering, and a rod-shaped bond glass (apex glass) 10 with a low melting point is placed in the winding groove 9 of the other core half 6b. Thereafter, the respective bond glasses 8 and 1o are melted and fused at the gap surfaces of the core halves 6a and 6b. fll is the core width.

Problems to be Solved by the Invention However, in the above-mentioned conventional structure, the coefficient of thermal expansion α of the ferrite 4 and the reinforcing glass 3 made of high melting point glass, which constitute the composite material substrate 5, is α1=α1 of the ferrite 4.
120x 10-'/'C1 Reinforced glass 3 made of high melting point glass is α2 = 102X 10-2/'C
Therefore, α1>α2, and when the gap is formed, as shown in Figure 6, a force acts to widen the gap,
There was a problem in that the magnetic gap surfaces 2 did not abut against each other sufficiently with only the force received from the gap forming jig, and the gap could not be formed with high accuracy.

Furthermore, since the thickness of the bond glass 8 as a glue material formed on the magnetic gap surface 2 must be made extremely thin due to the gap length, the bonding at the magnetic gap surface 2 is not sufficiently performed, and it cannot withstand subsequent machining. There were major problems such as the magnetic gap surface 2 peeling off due to failure of the magnetic gap.

Means for Solving the Problems In order to solve the above problems, the magnetic head of the present invention has a magnetic metal material constituting the magnetic core, and a glass material located on both sides of the metal magnetic material near the magnetic gap surface. and a composite material substrate, the other part of which is made of ferrite, the glass comprising a high melting point glass forming a magnetic gap surface, and a composite material substrate having a high melting point glass between the high melting point glass and the metal magnetic material at least in the magnetic gap surface. It has a structure consisting of sandwiched low melting point glass.

Effect According to the above structure, the coefficient of thermal expansion of low melting point glass is larger than that of ferrite, magnetic metal, and high melting point glass.
When melting and filling the groove in the plane of the magnetic gap, the material contracts significantly during the cooling process, and a pulling force acts on the ferrite and the high melting point glass. However, after polishing the magnetic gap surface, a predetermined stress is exerted on each region of the half core. When the gap is formed, the low melting point glass is remelted and the stress is relaxed and relieved, so that the land portion made of ferrite and the track portion made of the metal magnetic material and high melting point glass protrude compared to the low melting point glass. . Low melting point glass groove position, groove width,
By adjusting the depth of the groove, the track portion can be made to protrude more than the land portion, so that the track portions of the two cores can be completely butted together when forming the gap. In addition, during the cooling process after forming the gap, the low melting point glass contracts significantly, which causes a force to tighten the track section, and in addition to the force from the gap forming jig, a force from within the magnetic gap plane is used to accurately adjust the gap length. Can be formed well. In addition, when cutting the core after forming the gap into a predetermined head width, the cutting is done through completely fused and strong low-melting glass, so there is less risk of peeling off at the magnetic gap surface than in the past. There is no.

Example Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a perspective view of a magnetic head according to an embodiment of the present invention. It is the head. In Figure 1, 11
12 is an amorphous magnetic material, 12 is a composite material substrate, 13 is ferrite, 14 is reinforced glass, 15 is bond glass (pre-molded glass), 16 is a magnetic gap surface, and 17 is a winding groove. The amorphous magnetic material 11 is sandwiched on both sides by a composite material substrate 12 consisting of a high melting point reinforcing glass 14 and a low melting point bond glass 15 near the magnetic gap surface 16, and a ferrite 13 in the other parts. , the joining of the magnetic gap surfaces 16 is such that the magnetic gap surfaces 16
Reinforced glass 1 made of high melting point glass to form a part of
This is accomplished by fusing a bond glass 15 made of low melting point glass provided on the side surface of 4.

FIG. 2 shows both core halves 18a with straight curves forming gears.

18b shows the state of the magnetic gap surface 16. To form the gap, first, a groove is formed along the track made of the amorphous magnetic material 11 at the boundary between the reinforcing glass 14 and the ferrite 13 in the magnetic gap surface 16 of both core halves 18a and 18b, and a low melting point bond glass is placed in the groove. 15, the magnetic gap surface 16 is polished smooth, and a gap material 19 made of SiO2 is formed to a predetermined thickness by sputtering, and then both core halves 18a are formed.

Bond glass 1 provided within the magnetic gap surface 16 of 18b
This was done by fusion bonding in step 5. The magnetic head of this example is
Compared to the conventional magnetic head shown in FIG. 4, it was found that the adhesive strength at the magnetic gap surface 16 was greater and the gap accuracy was also extremely good. This will be described in more detail below.

FIG. 3 shows the state of the gap surface when the gap is formed. The thermal expansion coefficient of the low melting point bond glass 15 is that of ferrite 1
3. Since it is larger than the amorphous magnetic material 11 and the reinforcing glass 14, when it is melted and filled into the groove in the magnetic gap surface 16, it contracts greatly during the cooling process, and a pulling force acts on the ferrite 13 and the reinforcing glass 14. Therefore, the core halves 18a, 18b after polishing the magnetic gap surface 16
A stress as shown in FIG. 3(A) is acting on each region. At the time of gap formation, the bond glass 15 is remelted and the stress is relaxed, so that a land portion made of ferrite 13 and a track portion made of amorphous magnetic material 11 and reinforcing glass 14 are formed, as shown in FIG. 3(B). This is more prominent than the bond glass 15. By adjusting the position, groove width, and groove depth of the bond glass groove, it is possible to make the track portion protrude more than the land portion, so that the track portions of both core halves 18a and 18b are completely butted together when forming the gap. can be done.

In addition, in the cooling process after gap formation, the bond glass 15
As shown in FIG. 3(C), the force that tightens the track section is exerted, and in addition to the force from the gap forming jig, the gap length is formed with high accuracy by the force from within the magnetic gear lubricant surface 16. can do. Furthermore, as shown in FIG. 2, when cutting the core after forming the gap into a predetermined head width ρ2, the cutting is done through the bond glass 15, which is completely fused and has a high strength. Compared to cutting the conventional magnetic head shown in the figure, there is no fear of peeling off at the magnetic gap surface 16.

Effects of the Invention As described above, according to the present invention, it is possible to improve the gap accuracy and increase the adhesive strength on the magnetic gap surface, even though it uses a composite material substrate made of a plurality of materials with different coefficients of thermal expansion. Therefore, the yield of the entire magnetic head can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a magnetic head in an embodiment of the present invention, FIG. 2 is a perspective view illustrating the state of the magnetic gap surface immediately before gap formation in the same magnetic head, and FIG. 3 is a gap formation in the same magnetic head. 4 is a perspective view of a conventional magnetic head; FIG. 5 is a perspective view illustrating the state of the magnetic gap surface of the same magnetic head immediately before the gap is formed; FIG.
The figure is an explanatory diagram of the shape of the core when a gap is formed in the same magnetic head. 11... Amorphous magnetic material, 12... Composite material substrate, 13... Ferrite, 14... Reinforced glass, 1
5... Bond glass, 16... Magnetic gap surface agent Yoshihiro Morimoto Figure 1? Figure 3 Figure 4 Figure 3 Figure 6

Claims (1)

[Claims] 1. A metal magnetic material constituting a magnetic core, and composite material substrates located on both sides of the metal magnetic material and made of glass in the vicinity of the magnetic gap surface and ferrite in other parts. A magnetic head, wherein the glass is composed of a high melting point glass forming a magnetic gap surface and a low melting point glass sandwiching the high melting point glass between the metal magnetic material at least at the magnetic gap surface. 2. The magnetic head according to claim 1, wherein the metal magnetic material is an amorphous magnetic material.