JPS63142506A - Magnetic head - Google Patents

Abstract

PURPOSE:To obtain a magnetic head which has a high wear resistance, scarcely generates a sliding noise, and is capable of high density recording, by butting and joining a pair of core half bodies into which a sub-core consisting of an oxide magnetic material has been integrated, respectively, to a pair of holders consisting of a non-magnetic hard material, through a magnetic gap. CONSTITUTION:A pair of core half bodies 30a, 30b are constituted by integrating sub-cores 32a, 32b consisting of an oxide magnetic material, into opposed surfaces of holders 31a, 31b consisting of a non-magnetic hard material, respectively. Also, on the upper part of the holders 31a, 31b, projecting parts 36a, 36b having slanting faces 35a, 35b of a prescribed angle against a gap (g), respectively, and on said slanting faces, a metallic magnetic film 37 is formed. The holders 31a, 31b for forming a magnetic tape sliding surface are made of a non-magnetic hard material, therefore, its wear resistance is satisfactory and a sliding noise is scarcely generated. Also, since the core is formed by the metallic magnetic film 37, and the oxide magnetic material is used for the sub-core 32, with respect to a high magnetic force magnetic tape, information can be recorded with high density.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a magnetic head used in a magnetic recording/reproducing device such as a video tape recorder.

(Prior Art) In recent years, higher density has been promoted in magnetic recording and reproducing devices, and for this reason, the coercive force of magnetic recording media such as magnetic tape has been increased by about 5 times from about 3oo6e to about 1500δe. They are learning to use things. A magnetic head that records and reproduces signals on a magnetic recording medium with such a large coercive force is made of an oxide magnetic material that has a conventional ferrimagnetic crystal structure and a saturation magnetic flux density of 5000 Gauss or less. A magnetic head with a weak magnetization ability cannot record information at high density. For this reason, magnetic heads made of metallic magnetic materials with high saturation magnetic flux density have been developed.

A conventional example of this type of magnetic head will be described below.

The magnetic head 1 shown in FIG. 11 is a ring head made of a metal magnetic material made of a bulk material such as sendust using the same processing method as conventional oxide magnetic materials. That is, the core half 1a.

A gap q of track width TI, l is formed by a gap holding film (not shown) sandwiched between 1b and track width regulating groove 2.
is formed. The track width regulating groove 2 and the glass filling groove 3 formed at the bottom are filled with an inorganic adhesive 4 such as glass, and the coil 6 is wound in the winding groove 5 formed at the top. .

In the magnetic head 10 shown in FIG. 12, a head core is formed by the processing method shown in FIG. 11 using a metal magnetic material made of a bulk material such as sendust, amorphous, permalloy, etc. The center core 11 is completed by cutting the surface by machining or the like to reduce the thickness to a thickness equal to the track width T. On both sides of this central core 11 are M and -Z. A side holder 12 made of an oxide magnetic material such as single crystal ferrite is bonded with an organic adhesive or an inorganic adhesive. A portion of the center core 11 near the gap 0 and the track width T is filled with a non-magnetic material such as glass 13, and the winding groove 1 formed in the side holder 12 is filled with a non-magnetic material such as glass 13.
A coil 15 is wound around the coil 4 .

The magnetic head 20 shown in FIG. 13 has core halves 20a and 20b formed of an oxide magnetic material made of M, -Z, single crystal ferrite, etc., on the gap-opposing surfaces thereof, at a constant angle with respect to the gap Ω. A groove 21 having an inclined surface is formed. In addition, on this inclined surface, a metal magnetic film 2 such as sendust or permalloy is coated using thin film formation technology.
2, and a winding groove 23 and a glass filling groove 24 are formed in one of the core halves 20a and 20b, the core half 20b in the figure. and core half 20
A gap 9 with track widths T and J is formed between a and 20b through a gap protection film (not shown), and an inorganic adhesive such as glass 25 is applied to the tip of the winding groove 23 and the glass filling groove 2.
4 is filled and reinforced. Also, the coil 26 is in the winding groove 23.
is wrapped.

2. Description of the Related Art Magnetic heads using the above-mentioned metallic magnetic materials as cores have been known.

However, when the magnetic head 1 shown in FIG. 11 is used as a video head, the wear resistance is poor, and as shown in FIG. 14, M is made of oxide magnetic material. -70 compared to a magnetic head of the same size made of single crystal ferrite.
Since it wears out about four times faster, there is a problem of poor reliability. In addition, the specific resistance of the core made of metal magnetic material is small, and the track width T is small. Since the core thickness is larger, eddy current loss occurs and the recording/reproducing efficiency deteriorates. The following equation (1) expresses the skin depth δ of magnetic flux density due to eddy current loss. From this equation (1), it can be seen that the higher the frequency range, the shallower the skin depth δ becomes, and the magnetic properties deteriorate. It can be understood.

δ=fβ/(πfμ)...(1) However, δ is the depth of the skin, f is the specific resistance, f is the frequency used,
μ is magnetic permeability.

In the magnetic head 10 shown in FIG. 12, the central core 11 made of a metallic magnetic material is machined into a thin plate having a thickness equal to the track width TI,l.
Eddy current loss is less likely to occur, but advanced processing technology is required to make the plate thinner.

Generally, the side holder 12 is made of oxide magnetic material, especially M.

When the magnetic tape is made of −2° single crystal ferrite, there is a problem in that sliding noise with the magnetic tape occurs. Furthermore, the joining of the central core 11 and the side holders 12 also requires a sophisticated technique, resulting in a problem of high cost.

Although the magnetic head 20 shown in FIG. 13 has a shape suitable for mass production, the core halves 20a and 20b are made of oxide magnetic material, particularly M and -Z. When single-crystal ferrite was used, the problem of sliding noise frequently occurred as in the case of the magnetic head 10 shown in FIG. 12. Furthermore, if an oxide magnetic material is used for the core halves 20a and 20b,
The difference in thermal expansion coefficient with the metal magnetic film 22 is 130 XIO/
°C to 150
There was also the problem that tensile stress was generated in the 20b, making it more likely to be damaged. For this reason, the manufacturing yield was poor.

(Problems to be Solved by the Invention) The present invention solves the problems of conventional magnetic heads made of metal magnetic materials, such as poor wear resistance and eddy current loss, which deteriorates recording and reproducing efficiency. Alternatively, it requires advanced technology for processing, resulting in high costs, and it also solves the problems of sliding noise and being easily damaged = 6-, and has high wear resistance and low sliding noise. Moreover, it is an object of the present invention to provide a magnetic head having high band frequency characteristics and capable of recording information at high density on a magnetic recording medium with high coercive force.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention incorporates a subcore made of an oxide magnetic material into a pair of holders made of a non-magnetic hard material. A pair of core halves are formed, and these core halves are abutted and joined through a magnetic gap, and each core half is provided with a metal magnetic film tilted at a predetermined angle with respect to the magnetic gap forming surface. A magnetic head is constructed by forming layers.

(Function) According to the above configuration, the thermal expansion coefficients of the metal magnetic film and the holder serving as the substrate can be easily matched, and damage to the substrate can be prevented. Furthermore, since the magnetic tape sliding surface is formed of a holder made of a hard material, wear resistance can be improved, and at the same time, generation of sliding noise can be prevented.

In addition, a magnetic path is formed by providing a metal magnetic film only on the gap forming surface of the holder, which is a non-magnetic substrate, and its vicinity, and the sub-core including the back gap is formed of an oxide magnetic material with a higher resistivity than a metal magnetic material. Therefore, the occurrence of eddy current loss can be prevented, and a decrease in core efficiency due to crystal anisotropy can be prevented.

(Embodiment) An embodiment of the magnetic head according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. A pair of core halves 30
a and 30b are composed of holders 31a and 31b made of a non-magnetic hard material, respectively, and sub-cores 32a and 32b made of an oxide magnetic material incorporated at predetermined positions on the opposing surfaces of these holders 31a and 31b, respectively. ing. As the non-magnetic hard material, Al2O3, forsterite, crystallized glass, etc. are used, and as the oxide magnetic material, M is used. -Zo single crystal ferrite etc. are used. Furthermore, the holders 31a, 31b and the sub-cores 32a, 32b are bonded with an inorganic adhesive such as high melting point glass. Core half 30 configured in this way
a, at least one of 30b, in the figure, the core half 30b
A winding groove 33 and a glass filling groove 34 are formed in the side sub-core 32b. Moreover, the holders 31a and 31b
Projections 36a and 36b each have slopes 35a and 35b at a predetermined angle with respect to the gap Q.
is formed. A metal magnetic film 37 made of a thin metal magnetic material such as sendust, permalloy, or amorphous is formed on these slopes 35a and 35b. Then, a gap holding film (not shown) is sandwiched between opposing surfaces of the core halves 30a and 30b forming the gap q, and an inorganic adhesive 38 such as high melting point glass is filled into the winding groove 33 and the glass filling groove 34. , core half 30a, 3
0b are joined together. Further, a coil 39 is wound around the winding groove 33 .

Hereinafter, a method of manufacturing the magnetic head according to this embodiment will be explained with reference to FIGS. 2 to 9. In FIG. 2, non-magnetic hard materials 31a and 31b are machined to predetermined dimensions, and cutouts 40 for embedding sub-cores 32a and 32b are roughly formed by machining to form a holder 3.
Make 1a and 31b. At this time, the depth K of the notch 40
The relationship between M and the depth M of the winding groove 33 is expressed by the following equation (2).

K≧M+50 (μm) - (2) Next, as shown in FIG. 3, sub-cores 32a and 32b made of oxide magnetic material are assembled and bonded to holders 31a and 31b at predetermined positions using an inorganic adhesive. The gap facing surface 41 side is roughly polished by lapping or the like. Then, as shown in FIG. 4, first grooves 35a and 35b of a predetermined shape for forming the metal magnetic film 37 are formed at a depth dl and a processing pitch p1 by machining such as grindstone processing or wire saw processing. . Next, as shown in FIG. 5, a metal magnetic film 37 is formed to a thickness of TH on the gap facing surface 41 side of each core half 30a, 30b by sputtering, vapor deposition, or the like. This thickness T. is set so that the relationship between the track width T when the magnetic head is completed and the angle θ formed by the processed groove 35 is as shown in the following equation (3).

TH=TH/S! nθ-(3) and the gap facing surface 4 of each core half 30a, 30b
The metal magnetic film 37 formed in 1 is cut by a mechanical process such as lapping by the film thickness TH, and as shown in FIG.
The metal magnetic film 37 remains in the grooves 35a and 35b.
remove.

Next, as shown in FIG. 7, a second groove 42 is formed between the first grooves 35 by machining with a depth d2 and a machining pitch P2 (in this case, P=P2). and core half 3
At least one of 0a and 30b, the core half 30 in the figure
In b, a winding groove 33 and a glass filling groove 34 are formed with predetermined dimensions by machining. At this time, arrow A of the winding groove 33
The depth end portion shown by is arranged to coincide with the interface between the sub-cores 32a, 32b and the holders 31a, 31b, or in the vicinity of the holders 31a, 3Ib. Thereafter, the gap facing surface 41 is mirror-finished, and a gap retaining film (not shown) is roughly formed on the front gap facing surface portion 43.

Core halves 30a and 30b formed as described above
As shown in FIG. 8, the metal magnetic films 37 are butted together to form a track width T9 and a gap q, an inorganic adhesive 38 is inserted into the winding groove 33 and the glass filling groove 34, and pressure is applied. The core halves 30a and 30b are joined by heating. At this time, the first groove 35 and the second groove 42 are also filled with the inorganic adhesive 38, respectively. Next, slicing is performed at a predetermined processing pitch P3 at the position indicated by the dashed line, and a magnetic held core 30 as shown in FIG. 9 is obtained. Then, the tape is further cut by lapping or cylindrical grinding to the position shown by the dotted line to form a tape sliding surface having a predetermined radius of curvature, and to make the head depth a predetermined size. By winding the coil 39 in the winding groove 33 of the magnetic helad core 30, the magnetic head 30 shown in FIG. 1 is obtained.

According to this embodiment, the holder 31 is made of a non-magnetic hard material.
Since a and 31b form the magnetic tape sliding surface, the wear resistance is good and there is little sliding noise. Also, the metal magnetic film 3
Since the portion forming 7 is inside the groove 35' formed in the holders 31a and 31b mainly made of non-magnetic hard material,
It is easy to match the coefficient of thermal expansion of the material, and cracks due to stress and strain are less likely to occur, thereby preventing damage. Moreover, since the core is formed of a metal magnetic film 37 and the sub-core 32 is made of oxide magnetic material, information can be recorded at high density on a high coercive force magnetic tape, making it possible to create a highly reliable magnetic head. can be manufactured at low cost.

FIG. 10 shows another embodiment of the present invention. The magnetic head 50 according to the present embodiment has holders 51a and 51b formed of a non-magnetic hard material at the winding portion of the coil 53 with a predetermined dimension T.
It is cut out leaving only 3×Th. According to this embodiment, the sub-cores 52a, 52b and the holder 51a,
51b exist together in the coil winding part, especially in the high frequency range, the holders 51'a and 51b
The leakage magnetic field generated on the side can be reduced, and the efficiency is improved. In particular, the bottom dimension is preferably 50 μm or more in consideration of strength.

[Effects of the Invention] As described above, according to the present invention, since the magnetic tape sliding surface is formed of a holder made of a non-magnetic hard material, wear resistance is good and sliding noise can be reduced. Furthermore, since the metal magnetic film is formed within the groove of the holder, it is easy to match the coefficient of thermal expansion of the materials, and damage due to cranking is less likely to occur. Moreover, high-density information recording becomes possible in correspondence with a high coercive force magnetic tape.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the magnetic head according to the present invention, FIGS. 2 to 9 are perspective views showing the manufacturing process of the magnetic head shown in FIG. 1, and FIG. 10 is a perspective view showing an embodiment of the magnetic head according to the present invention. FIGS. 11 to 13 are perspective views showing conventional magnetic heads, and FIG. 14 is a graph showing life test results for different types of magnetic heads. 30, 50...Magnetic heads 30a, 30b, 50a, 50b ・D 7 halves 31a, 31b, 51a, 51b...Holder 32a
, 32b, 52a, 52b --- Sub core 37...
Metal magnetic film q...Magnetic gap agent Patent attorney
Noriyuki Ken Yudo Uji Hiroshi Figure 13 Life test time w4 Ichour) Figure 14 6 Contents of amendment Procedural amendment (voluntary) 1. Indication of incident Patent Application No. 1987-287756 2. Name of invention Magnetic head 3. Relationship with the case of the person making the amendment Patent applicant (307) Toshiba Corporation 4, agent 1-1 Shibaura-chome, Minato-ku, Tokyo 105 & Column for detailed description of the invention in the specification subject to amendment and correction do. (2) "High melting point" on page 9, line 13 is corrected to "low melting point." (3) “Sub core 32a, 32
After "b", insert "high melting point glass, etc." (4) "Glass filling groove 34" on page 12, line 2
After , insert ``low melting point glass, etc.''. (5) Figure 1 of the drawings will be corrected as shown in the attached sheet. Figure 1 above

Claims (1)

[Claims] A pair of core halves are formed by incorporating subcores made of an oxide magnetic material into a pair of holders made of a non-magnetic hard material, and these core halves are butted and joined via a magnetic gap. . A magnetic head, characterized in that each core half has a metal magnetic film layer inclined at a predetermined angle with respect to the magnetic gap forming surface.