JPS6226607A - Magnetic head and its manufacture - Google Patents

Abstract

PURPOSE:To execute the magnetic recording to the high-reluctance force magnetic tape without fail by burying the core part composed of the metallic magnetic substance through the nonmagnetic material at the edge surface contacting slidable to the magnetic tape of the core main body composed of the oxide type magnetic substance and providing the gap part at the core part. CONSTITUTION:At a curved sliding surface 1A side to slide with the magnetic tape of a core main body 1, a core part 6 composed of the metallic magnetic material is buried and a nonmagnetic layer 7 is laid between the core part 6 and core main bodies 2A and 2B. By the prescribed azimuth angle, a gap part 8 is provided at the center of the core part 6. Thus, when the core part 6 composed of the metallic magnetic material is provided at the core main body 1 composed of the ferrite, the saturated magnetic flux density of the core part 6 is large, and therefore, even when the large recording electric current is supplied to a winding 12, the magnetic flux of the core part 6 will not be saturated. Thus, even in case of the high-reluctant force magnetic tape, the magnetic recording can be executed without fail.

Description

[Detailed description of the invention] (Industrial applicability gf) The present invention relates to a magnetic head and a method of manufacturing the same.

(Prior Art and its Problems) Recently, magnetic tapes with high coercive force and excellent resistance to external magnetic fields have been used as recording media for video tape recorders (hereinafter referred to as VTRs).

Incidentally, the magnetic head of a VTR is composed of a core made of an oxide-based magnetic material such as ferrite, but the saturation magnetic flux density of the core is relatively small at about 4,000 to 5,000 Gauss. Therefore, if a large recording current is supplied to the magnetic head in order to magnetize a magnetic tape with high coercive force, the magnetic flux in the core may become saturated before the magnetic tape becomes tS, leading to incomplete recording on the magnetic tape. There is.

Therefore, it has recently been proposed to form the core of the magnetic head from a metallic magnetic material with a high saturation magnetic flux density.

However, when the core is made of a metallic magnetic material, the specific resistance of the core becomes small, resulting in a decrease in magnetic permeability in the video band, that is, the high frequency signal band. Also,
A core made of a magnetic metal material also has the disadvantage of poor wear resistance.

(Means for Solving the Problems) The present invention has been made to solve the above problems, and includes a core body made of an oxide-based magnetic material on the end surface side that is in sliding contact with the magnetic tape. It is an object of the present invention to provide a magnetic head in which a core made of a magnetic metal material is embedded through a non-magnetic material and a gap is provided in the core, and a method for manufacturing the same.

(Embodiments of the Invention) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a magnetic head according to the present invention. This magnetic head includes a core body l made of ferrite. The core body 1 consists of core halves 2A and 2B.
A joining groove 3.3 is provided on the opposite end face of the. The core halves 2A and 2B are joined via a glass material 4 filled in the joining groove 3.3 and a glass layer 5 located between the opposing end surfaces. A core part 6 made of a metal magnetic material is embedded in the curved sliding contact surface LA side of the core body 1 that joins with the magnetic tape. A magnetic layer 7 is interposed therebetween.A gap portion 8 is provided in the center of the core portion 6 at a predetermined azimuth angle.This gap portion 8 is formed by a substantially semi-conical regulating recess 9.9 to prevent a magnetic tape (not shown) from being formed. The length dimension is set to correspond to the track width of these regulating recesses 9.9.
is provided across the core portion 6 and the core halves 2A, 2B,
A glass material 10 is filled.

A winding window 11 is formed in one of the core halves 2A, and a winding 12 is wound around the core halves 2A and 2B through the winding window 11.

In this way, when the core body 1 made of ferrite is provided with the core part 6 made of a metal magnetic material, the saturation magnetic flux density of the core part 6 is large, so even if a large recording current is supplied to the winding 12, the core part 6 Therefore, magnetic recording can be performed reliably even on a magnetic tape with high coercive force. Furthermore, since the core body 1 made of ferrite has a high transmittance/a ratio, even video signals can be efficiently reproduced. Furthermore, since the core portion 6 is only provided on a part of the sliding surface LA of the ferrite core body 1 with the magnetic tape, the abrasion resistance of the magnetic head can also be maintained.

Next, a manufacturing method according to the present invention will be explained.

That is, as shown in the second Δ(a), rectangular parallelepiped ferrite materials 2A' and 2B' are used, and a stepped portion 20 is provided on these ferrite materials.

On the other hand, as shown in FIG. 2B, a metal magnetic material 6' to be fitted onto the stepped portion 20 is prepared. Then, two adjacent surfaces of this metal magnetic material 6' are polished to a mirror finish, and a high melting point nonmagnetic film 1, for example, a nonmagnetic film 7A made of 5iOz, Al2O2, etc., is sputtered on these two surfaces to a thickness of about 0.1 to 0
．． Provided with a thickness of 2 gm.

Next, on the step part 20 of the ferrite material 2A'(2B'),
As shown in FIG. 3C, a glass layer 7B having a high melting point and approximately the same coefficient of thermal expansion as ferrite is provided by sputtering (or coating) to a thickness of about IILm. and,
As shown in FIG. 2(d), a nonmagnetic film 7
The metal magnetic material 6' is fitted with A in contact with the glass layer 7B.

The metal magnetic material 6' is pressed onto the stepped portion 20 while being heated to approximately 750° C., and the non-magnetic film 7A and the glass layer 7B are applied to the stepped portion 20.
It is fixed through. As a result, the core half block 21.
22 is obtained.

Next, as shown in the same figure (e), the core half block 2
The metal magnetic material 6 is attached to the joint surface 21a (22a) of 1 (22).
Semi-conical regulating recesses 9a to 9d are formed spanning the ferrite material 2A'(2B') and the ferrite material 2A'(2B'). Regulation recesses 9a, 9b
The distance t between the metal magnetic material 6' and 9C19d has a length dimension corresponding to the track width of the magnetic tape. In addition, as shown in FIG. 3(f), a joint groove 3 and a winding window 11 are formed on the joint surface 21a of one core half block 21, and a joint surface 22a of the other core half block 22 is formed.
Only the bonding groove 3 is formed in. Glass materials 4' and 10 having a low melting point (approximately 450'C) and approximately the same coefficient of thermal expansion as ferrite are provided in the joint grooves 3.3 and regulating recesses 9a to 9d of each core half block 21.22. ′ respectively.

After filling the glass materials 4' and 10' in this manner, the core half blocks 21 and 22 are mirror-finished, and as shown in FIG. A glass layer 5' is formed by sputtering, and a gap layer 8' made of quartz glass is formed on a metal magnetic material 6'.
is formed by sputtering. This gap layer 8'
is formed to have a thickness 1/2 of the desired gap width.

Next, as shown in the same figure (h), the core half block 2
1.22 joint surfaces 21a, 22a, that is, glass layer 5'
, 5' are butted against each other, and a glass t42 having a low melting point and approximately the same coefficient of thermal expansion as ferrite is placed in the winding window 11.
Insert 3. And these core half blocks 21
．． 22 at about 450° C. and pressed against each other, the low melting point glass material 4' filled in the bonding groove 3, the low melting point glass material 10' filled in the regulating recesses 9a to 9d, the low melting point glass layer 5' and The core half blocks 21, 22 are joined via the glass rod 23 mentioned above. As a result, (i)
A composite block 24 shown in is obtained.

Next, as shown by the dotted line in Figure (i), the composite block 2
4 at a predetermined azimuth angle θ to produce a pair of head bodies 25 and 25 shown in FIG.

Finally, as shown in FIG. , a magnetic head of the present invention (see FIG. 1) is obtained which has a predetermined pump depth and a curved sliding contact surface LA.

As explained above, when the core half blocks 21 and 22 are joined at a low temperature (approximately 450'0) through a glass material with a low melting point, the metal magnetic material 6 is attached to the stepped portion 20 of the ferrite material 2A' (2BN It is possible to prevent the high melting point non-magnetic film 7A and the glass layer 7B for fixing the blocks 21 and 22 from melting when the blocks 21 and 22 are bonded.Therefore, the core part 6 is completely fixed to the core body 1. In addition, since the E glass layer 7B and the low melting point bonding glass material have the same coefficient of thermal expansion as the ferrite materials 2A' and 2B', Core body l, core part 6, and ferrite materials 2A', 2B
'It is also possible to prevent the mutual bonding state from becoming incomplete. Therefore, the temperature resistance characteristics of the magnetic head are also significantly improved.

(Effects of the Invention) According to the present invention, a core portion made of a metal magnetic material is embedded via a nonmagnetic material on the end surface side of the core body made of an oxide-based magnetic material that comes into sliding contact with a magnetic tape, and the core portion Since the gap portion is provided in the head, it is possible to provide a magnetic head with excellent wear resistance that can reliably perform magnetic recording on a magnetic tape with high coercive force and can efficiently reproduce video signals. In addition, the core part is fixed to the core body through a non-magnetic material with a high melting point and the same coefficient of thermal expansion as the core body, and the core halves forming the core body are joined together with a low-melting point non-magnetic material. Therefore, a magnetic head with excellent connection reliability can be obtained.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a magnetic tube according to the present invention, and FIGS. 2(a) to (j) are diagrams for explaining each manufacturing process of the manufacturing method of the present invention. 1... Core body. 4...Glass material, 5...Glass layer, 6...Core part, 6'...Metal magnetic material, 7A...Magnetic film, 7B...Glass layer, 8...Gap part , 20... Step part, 21.22... Core half block. 1st prisoner 2B 2nd vA

Claims (1)

[Claims] 1. A magnetic head comprising a core body made of an oxide-based magnetic material and a gap portion provided at one end side of the core body, the magnetic head comprising a core body made of a metal magnetic material at one end side of the core body. 1. A magnetic head, characterized in that a core portion made of the same material is embedded through a non-magnetic material, and the gap portion is located in the core portion. 2. Providing a stepped portion in the oxide-based magnetic material for forming the core half, and forming a metal magnetic material in the stepped portion with a high melting point and approximately the same coefficient of thermal expansion as the oxide-based magnetic material. a step of fixing via a non-magnetic layer to form a core half block, and a step of butting each bonding surface of the pair of core half blocks having the metal magnetic material and joining via a low melting point non-magnetic material. A method of manufacturing a magnetic head, comprising: 3. The method of manufacturing a magnetic head according to claim 2, wherein the oxide-based magnetic material is ferrite.