JPS6018805A - Magnetic head and its production - Google Patents

Abstract

PURPOSE:To increase the mechanical strength of a magnetic head and at the same time to compensate the magnetic loss of the head by means of a ferrite core in order to improve the reproduction efficiency with high permeability, by jointing ferrite cores having bridge bars centering on a ''Sendust'' core at its both sides with partial use of glass. CONSTITUTION:Two ''Sendust'' wafers 20 an 21 are finished to mirror surfaces, and a winding groove 22 is provided to the wafer 20. Then a nonmagnetic film 23 is coated to an area serving as a front gap. These two wafers are butted and jointed to each other by putting a silver solder 24 into the groove 22. Then this joined wafer is cut into weld blocks with application of fabrication to obtain its thickness equal to the desired track width. The front gap part holds a nonmagnetic film 3, and the back gap part is adhered by a silver solder. At the same time, a part of a winding window 4 is adhered with the remaining silver solder.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic head suitable for application to a metal tape having a large coercive force, and a method for manufacturing the same.

Conventional magnetic heads that handle high-frequency signals, such as those used in video tape recorders, have used ferrite materials that have excellent wear resistance and high specific resistance. The saturation magnetic flux density of is small. In order to increase the saturation magnetic flux density in the front gap portion, a magnetic head having a structure as shown in FIG. 1 or 2 has been proposed in which the core material of the front gap portion is made of a metal magnetic material such as Sendust. These composite magnetic heads have the characteristic of being able to increase the saturation magnetic flux density by compensating for the loss in the high frequency range due to the low specific resistance of the metal magnetic material, but they have large variations in characteristics and lack of mechanical strength. However, it was only possible to put it into practical use in environments where the device was used in a favorable environment.

In view of this point, the present invention aims to provide a magnetic hemmet with a new structure that eliminates the above-mentioned drawbacks, and a method for manufacturing the same.

According to the present invention, the auxiliary core has a U-shaped notch whose inner surface is substantially parallel to the front gap portion of the metal magnetic core and the portion corresponding to the winding window thereof, and Since a non-magnetic bridging piece is provided between the upper parts of the inner side surface at the part corresponding to the front gap part, mass production of ferrite cores is easy, and the part near the gap is also relatively free of non-magnetic material. Due to its long existence, this portion does not form a gap with respect to adjacent channels, thus improving the magnetic properties. Further, according to the manufacturing method of the present invention, a desired magnetic head can be manufactured extremely easily.

A detailed explanation will be given below according to examples.

FIG. 3 shows one embodiment of the magnetic head according to the present invention. In the figure, (1) and (2) are half cores made of a metal magnetic material such as sendust, and this core half has a non-magnetic spacer (3) between its front gap forming surfaces to join the pack gap. By doing so, we are trying to unify them. In addition, the above-mentioned
A coil winding window (4) is provided between the knobs.

(5) and (6) are ferrite cores bonded to each surface of the magnetic path forming surface of the integrated core.
) has notches (7) and (8) at the portions corresponding to the front gap portion and the coil winding window (4), and a bridging piece made of non-magnetic glass ( 9) I have (10). These bridging pieces (9) and (10) sandwich the front gap portion of the Sendust core from both sides, thereby reinforcing the mechanical strength of the core half-closed at the corresponding portion. This prevents the corresponding portion, which is simply a half-core portion abutted against each other, from being missing or misaligned during the manufacturing process or during use. In addition, the integrated core half-vacation (
1) Each core thickness (11〉) in (2) defines the track width 3
- However, it has been confirmed that the core is thin and has a half width, which can accommodate very narrow track widths (for example, 30 mm or less). (12) is a winding.

In this way, the magnetic head of the present invention has a Sendust core and a ferrite core with some glass bridging pieces joined to both sides of the Sendust core, increasing the mechanical strength of the Sendust core and reducing its magnetic loss. It is now possible to supplement this with a similar core and further improve the reproducing efficiency due to its high magnetic permeability.

Next, a method for manufacturing such a magnetic head will be explained. FIG. 4 shows the manufacturing method of the Sendust core. Finish two sendust wafers (20) and (21) to a mirror finish, and process a winding groove (22) on one of the wafers (20).
A nonmagnetic film (for example, S f O2) (23) is deposited on the portion that will become the front gap in the future by vapor deposition or sputtering. Next, these two wafers are butted against each other and silver solder (for example, J I SBA) is applied to the winding groove (22).
g-8) Insert (24), apply a weight (0.4 to 4 kg/cm2) 4- in vacuum (or in a hydrogen atmosphere), and perform silver soldering at a temperature of 700 to 900°C (No. Figure 4 (a)). Thereafter, the welded block as shown in FIG. 4(b) is cut as shown by the dotted lines. The cut core is molded so that its thickness becomes a desired track width (for example, 20IJT11). As shown in FIG. 4(C), the Sendust core thus obtained has a front gap part sandwiching the non-magnetic film (3), a back gap part which is soldered with a solder, and a part of the winding window (4). are joined with the remaining silver solder.

FIG. 5 shows a method for manufacturing a ferrite core which is capable of reinforcing the Sendust core from both sides and increasing the reproduction efficiency of the head due to its high magnetic permeability in the high frequency range. As shown in the same figure (a), the glass substrate (25
) with a notched groove (26) on the polycrystalline front gap (
27) and insert the glass rod (28) into this groove. This molded body of ferrite and glass is heated in a vacuum (or in an inert atmosphere) to the melting point of the glass rod. In this way, as shown in the same figure (b), it is possible to obtain a block in which the glass rod is partially fused (29) to the front gap (27) and has some holes (30) that are not filled with glass. can. Thereafter, the glass substrate (25) is removed, cut along the dotted lines, and thickened to obtain a reinforcing ferrite core as shown in FIG.

The Sendust core and ferrite core molded as described above are bonded together using an organic adhesive (for example, cyanoacrylate adhesive), and winding is applied thereto to obtain a magnetic head as shown in Fig. 3. I can do it. It goes without saying that the reinforcing ferrite core should preferably have high magnetic permeability in the frequency range used by the magnetic head, but it is also desirable to use polycrystalline ferrite that has little magnetic anisotropy.

The magnetic head constructed as described above has a front gap made of a metal magnetic material such as sendust, so it is highly effective for recording on high coercive force media such as metal tapes, and it also has the feature that it is highly effective for recording on high coercive force media such as metal tapes. Because it is reinforced with steel, it has strong mechanical strength and can improve reproduction efficiency in the high frequency range. Furthermore, since the front gap part is reinforced with a non-magnetic bridging piece provided in the notch of this Fairlight core, the wear resistance of the front gap part can be improved. It is possible to prevent the Sendust cores, which are simply placed opposite each other, from generating mechanical vibrations due to contact with the tape and thereby generating noise.

[Brief explanation of drawings]

1 and 2 are configuration diagrams of a conventional magnetic head, FIG. 3 is a configuration perspective view of an embodiment of the present invention, and FIG. 4 is a configuration perspective view showing the manufacturing procedure of the Sendust core of the present invention. FIG. 5 is a structural perspective view showing the manufacturing procedure of the reinforcing core made of ferrite according to the present invention. (1)(2)・・・Core half-off (Sendust core),
(3)... Non-magnetic spacer, (4)... Winding window, (9)... Bridging piece. Patent applicant Sanyo Electric Co., Ltd. Representative Kaoru Iue 8- Ward 17- Ward 5 Bin

Claims (2)

[Claims] (1) A magnetic path forming surface of a metal magnetic core is provided with a non-magnetic spacer between the front gap forming surfaces, a hack gilt portion is joined, and a coil winding window is provided between both gap portions, and the front gap It has a U-shaped notch whose inner surfaces opposite to the portion corresponding to the front gap and the winding window are substantially parallel, and a non-contact portion is formed between the upper portions of the circular inner surfaces at the portion corresponding to the front gap portion of the notch. A magnetic head in which a ferrite core having a magnetic bridging piece is bonded, and the bridging piece reinforces the mechanical strength of the front gap portion. (2) Place a polycrystalline ferrite block having a notch groove for a winding window on a substrate so that the notch groove faces the substrate, insert a rod-shaped glass material into the notch groove, heat the glass material, and cut out the notch. The glass material is welded to the notched groove so as to leave the opening side of the groove and a winding window, and then the ferrite 1-IF block is separated from the substrate and sliced to create an auxiliary core. A method of manufacturing a magnetic head in which a core is joined to a metal magnetic core having a non-magnetic spacer between surfaces forming a front gap portion.