JPH0138724Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention aims to provide a magnetic head suitable for recording and reproducing high-frequency signals such as video information, which has excellent mechanical strength and can improve reproduction efficiency. . Alloy magnetic materials such as sendust, which have a high saturation magnetic flux density, are attracting attention as core materials for magnetic heads applied to high coercive force media. In order to overcome the low resistivity of this material, the total thickness of the core formed from this alloy magnetic material is reduced, and a magnetic material with high resistivity, such as ferrite, is added to it, a so-called composite material. Magnetic heads have been proposed. FIG. 1 shows an exploded perspective view of an intermediate product of a conventional magnetic head of this type.
Reference numeral 1 denotes a core main body, and 2 and 2 denote sub-core bodies, which are joined with an adhesive so that their magnetic path forming surfaces abut each other. The core body 1 consists of core halves 3 and 4 made of an alloy magnetic material such as sendust, which are joined together using an adhesive 5 such as silver solder so as to have a predetermined gap length between their abutting surfaces. , a working gap 6 and a coil window 7 defining the lower end of the working gap and winding a coil (not shown). The core body 1 is provided with inclined surfaces 8, 8 in order to reduce spacing loss with respect to the recording medium. Each core sub-body 2 is made of a non-magnetic material 9 such as lead glass.
and a magnetic body 10 made of a magnetic material having a high specific resistance such as ferrite are bonded together with an adhesive such as low melting point glass, and the non-magnetic body 9 is arranged so as to face the upper magnetic path of the core main body 1 and has a magnetic body 10. The bodies 10 are each selected to face the lower magnetic path.
The magnetic body 10 has a cutout hole 11 on its upper surface at a location opposite to the coil window 7, through which a coil can be wound around the coil window 7. The non-magnetic material 9 and the magnetic material 10 in this core sub-body 2 are joined by the adhesive, as is clear from FIG. 2 which shows an enlarged view of this joint.
The adhesive 12 is simply filled between the opposing surfaces of the lower surface of the magnetic body 10 and the upper surface of the magnetic body 10. This bond is somewhat weak against stress in the plane direction, and has an undeniable drawback in terms of mechanical strength. This drawback may result in the non-magnetic material 9 being missing during the process of molding the medium contacting surface of the magnetic head with an abrasive tape or during use of the magnetic head. In addition, core subbody 2
Also, inclined surfaces 13, corresponding to the above-mentioned inclined surfaces 8, 8,
I am trying to have 13. After the core main body and sub-body bodies 1 and 2 are integrated as described above, the medium contacting surface 14 is formed with abrasive tape as typically shown by the dashed line in FIG. It has depth. By the way, in this case, the distance 15 between the surface of the non-magnetic material 9 of the core sub-body 2 facing the magnetic material 10 and the surface parallel to the surface and including the lower end of the operating gap 6 is sufficiently set as shown in FIG. 3A. small (e.g.
(approximately 10μ), then during the above molding process, ○ in the figure
There is a risk that the non-magnetic material 9 and the magnetic material 10 may separate at the marked location 16, so for safety reasons, please keep the distance 1.
5 as shown in Figure 3B (for example, 40 to 50μ)
However, by doing this, the area occupied by the magnetic material 10 in the magnetic path becomes smaller, and the cross-sectional area of the magnetic path becomes substantially smaller, so the magnetic resistance is increased to improve the regeneration efficiency. It will cause it to drop. The present invention has been devised in view of this point, and aims to provide a new and useful magnetic head that satisfies both the improvement of mechanical strength and the improvement of regeneration efficiency, which were previously thought to be contradictory. Figure 4 is a front view of the magnetic head intermediate product of the present invention.
FIG. 5 is a partially enlarged view, and FIG. 6 is an exploded perspective view. As shown in each figure, the main body of the core is substantially the same as the conventional one explained in connection with FIG. 1, so the same figure numbers will be given and the explanation thereof will be omitted. core subbody 2
0 and 20 are made by bonding a non-magnetic material 21 such as lead glass and a magnetic material 22 made of a magnetic material with high specific resistance such as ferrite with an adhesive 23 such as low melting point glass. In this case, magnetic material 2
2 has a notch hole 24 on its upper surface at a location opposite to the coil window 7 so that a coil can be wound around the coil window 7 through the notch hole, and the non-magnetic material 2
1 is characterized by having a convex portion 25 that engages with the notch hole 24, as shown in the figure. When the non-magnetic material 21 and the magnetic material 22 are bonded, the adhesive 23 also flows to both sides of the convex portion 25 facing the upper inner surface of the notch hole 24, as shown in FIG. can be significantly increased. Therefore, even if the medium contact surface is formed after this core sub-body 20 is joined to the core main body 1 , the non-magnetic material 21 and the magnetic material 2 of the core sub-body are
There is no risk of peeling of the joint between the two parts. Also, since the convex portion 25 of the non-magnetic material 21 is inserted into the notch hole 24 of the magnetic material 22 by approximately 30 to 40 μm, the shaded area 26 shown in FIG.
Since the area of the magnetic body 22 attached to the core main body 1 can be increased over the period of time, the magnetic resistance can be reduced by that amount, and the reproduction output characteristics can be improved.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a conventional magnetic head intermediate product, FIG. 2 is a partially enlarged view of the joining portion of the core subbody, and FIGS. 3A and 3B are front views showing the drawbacks of the conventional structure. Fig. 4 is a front view of the magnetic head intermediate product of the present invention, Fig. 5 is a partially enlarged view thereof, Fig. 6 is an exploded perspective view, and Fig. 7 is a magnetic head intermediate product for explaining the effects of the present invention. It is a front view. Explanation of main drawing numbers, 1 ...core main body, 20 ...core sub-body, 21...non-magnetic material, 22...magnetic material, 2
4... Notch hole, 25... Convex portion.

Claims (1)

[Claims for Utility Model Registration] (1) A core body formed of an alloy magnetic material and having a working gap and a coil window defining the lower end of the working gap and winding a coil, and a magnetic core body of the core body. A non-magnetic material attached to the path forming surface and facing the upper magnetic path of the core main body and a magnetic material facing the lower magnetic path of the core main body and having a notch hole facing the coil window on the upper surface are joined. In the magnetic head, the non-magnetic body includes a convex portion that engages with the notch hole, and a space between a lower surface of the non-magnetic body and an upper surface of the magnetic body opposite thereto. and a magnetic head, characterized in that the non-magnetic material and the magnetic material are joined by an adhesive filled between the left and right side surfaces forming the convex portion and the hole wall surface of the notch hole opposing thereto. . (2) The magnetic head according to claim (1), wherein the protrusion extends further below the lower end of the operating gap.