JPH0118492B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic head suitable for high-density magnetic recording compatible with high coercive force magnetic media.

Magnetic heads used in video tape recorders (VTRs) and general tape recorders, which perform high-density magnetic recording and playback using high-coercivity magnetic media, have different recording and playback characteristics in order to achieve smaller size and longer operation times. In order to achieve this, the front core, which has an operating gap and faces the magnetic recording medium, and the rear core, which constitutes the rear magnetic circuit of this front core, are made of the same or different materials with different characteristics. The performance is improved by connecting the two to each other.

As such a joint type magnetic head, those disclosed, for example, in Japanese Patent Publication Nos. 55-40923 and 1982-114114 are known.

In the former magnetic head, as shown in FIG.
are integrally combined via a mutual diffusion layer. In this case, since the front core 1 and the rear core 2 are made of the same material, a relatively good bond can be obtained, but there is a drawback that special heat treatment must be performed for bonding.

In addition, as shown in FIG. 2, the latter magnetic head has an adhesive groove 7 formed on the rear core side of the joint surface 6 between the front core 4 made of Sendust and the rear core 5 made of ferrite. The adhesive groove 7 is filled with an adhesive 8 to fix the front core 4 and the rear core 5.

However, in the case of joining dissimilar materials such as metal and ferrite, it is difficult to obtain a joint state with good magnetic properties and mechanical strength with the above-described structure.

In either case, there is also the problem that it is difficult to achieve positioning accuracy when joining the front core and the rear core.

This invention was made in view of the above points,
The object of the present invention is to improve the bonding state of the bonded type magnetic head as described above, thereby increasing the magnetic properties and mechanical strength.

Therefore, in the magnetic head according to the present invention, one of the joint parts of the front core and the rear core is provided with a concave part and the other part is provided with a convex part so that they fit into each other, and both opening ends of the concave part of this joint part are approximately L. A gluing groove is formed at the joint between the front core and the rear core by a letter-shaped notch, and this gluing groove is filled with adhesive to effectively utilize the shrinkage force when the adhesive dries to create a strong structure. This is to obtain a bonded state.

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4.

The front core 11 is constructed by joining a pair of front core halves 11a and 11b made of Sendust with a thin plate-shaped non-magnetic gap forming material sandwiched between them, and has a semicylindrical shape as a whole. The track-processed groove 13 makes the thickness shorter than the thickness t of the front core 11 and is finished to match a predetermined track width.

At the rear surface of the front core 11, that is, at the joint with the rear core to be described later, there is a rectangular recess 15, which is indicated by width a and depth b in FIG.
furthermore, both opening ends of this recess 15 are provided with a fourth
As shown in the figure, adhesive grooves 16a and 16b are cut out in a substantially L-shape by c in the width direction and d in the front-rear direction.

On the other hand, the rear core 17 constituting the rear magnetic circuit of the front core 11 is formed from a rectangular parallelepiped material made of ferrite, and has a concave portion 15 of the front core 11 on the front surface where it joins with the front core 11. A rectangular convex portion 18 that fits snugly is provided to protrude forward, and a portion of the front end thereof is cut out into a rectangular shape to form a window 19 for storing the winding wire.

Front core 11 and rear core 1 formed in this way
7 and the concave portion 11 and convex portion 1 of each other as shown in the figure.
8 are fitted together in the front-rear direction, and an adhesive 20 is filled into an adhesive groove formed at the joint portion and dried.

In this way, as the adhesive dries, it shrinks in the front, back, right and left directions as shown by the arrows in FIG. Glued.

In addition, the contact area increases due to the uneven fitting of the joint portion, which also increases the joint strength, improves the joint position accuracy, and improves the magnetic properties.

In addition, when actually mass-producing this magnetic head, the above-mentioned recesses and protrusions as well as adhesive grooves are formed in advance on the columnar front core material and rear core material, which are each longer than the thickness of the core. After forming winding storage windows, etc. and fitting them together, filling the adhesive groove with adhesive and drying, the material block is sliced with a cutter in a direction perpendicular to the longitudinal direction, and the gap surface is cut. It will be manufactured by polishing it into an arc shape.

As described above with respect to the embodiments, according to the present invention, even if the core joint type head is made of dissimilar materials, the joint strength is strong and the joint position is high due to the fitting of the joint parts and the effective use of the shrinkage force of the adhesive. Good accuracy,
Magnetic properties are also significantly improved.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of a conventional core-joint magnetic head made of the same material, and FIG. 2 is a perspective view showing an example of a conventional core-joint magnetic head made of different materials. FIG. 3 is a perspective view showing a fitted state of the front core and rear core of a magnetic head according to an embodiment of the present invention, and FIG. 4 is a plan view showing the same state of being filled with adhesive. 11... Front core, 12... Working gap, 1
5... Recessed portion, 16a, 16b... Adhesive groove, 17
... Rear core, 18 ... Convex portion, 19 ... Winding storage window, 20 ... Adhesive.

Claims (1)

[Claims] 1. In a magnetic head formed by joining together a front core that has an operating gap and faces a magnetic recording medium, and a rear core that constitutes a rear magnetic circuit of the front core, the front core and the rear core are connected to each other. The front core and the rear core are joined by providing a concave part on one side of the joint part and a convex part on the other side so that they fit into each other, and cutting out both ends of the opening of the concave part of the joint part in a substantially L-shape, respectively. 1. A magnetic head characterized in that an adhesive groove is formed in the magnetic head, and the adhesive groove is filled with an adhesive.