JPS6215923B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a core for a magnetic head.

Conventionally, permalloy, ferrite, sendust, etc. have been used as core materials for magnetic heads, but permalloy has a short lifespan due to high wear due to friction with the magnetic tape, and has a saturation magnetic flux density of approximately 8000G, making it highly retainable. The saturation magnetic flux density is insufficient to erase or record on a magnetic tape.
The drawback is that it is difficult to manufacture a head that fully demonstrates the performance of the tape.

On the other hand, ferrite has excellent wear resistance and high frequency properties, but its saturation magnetic flux density is approximately 5000G.
This is lower than the above-mentioned permalloy, and its workability is also poor, so it has the drawback of requiring a large amount of processing cost when being processed into a core.

Furthermore, sendust has excellent wear resistance and has a high saturation magnetic flux density of approximately 10,000G, making it an ideal head core material in terms of properties, but like ferrite, it has poor workability and requires a large amount of processing cost to construct the core. required. Therefore, in recent years, in order to make the processing of sendust easier, a method has been proposed in which molten sendust is jetted out of a nozzle and is rapidly cooled by hitting a rotating roller to continuously produce sendust ribbons. . However, with this method, the conditions for producing the sendust ribbon are limited to a very narrow range, and outside of these conditions, the sendust becomes fine powder or flakes, which poses a problem in mass production. In addition, in order to efficiently process the core from the Sendust ribbon made by the above method, it is necessary to perform punching with a press, etc. However, depending on the processing conditions of the Sendust ribbon, pressing However, if we set the condition that it could only be obtained by pressing, which would be difficult to obtain, the manufacturing conditions for Sendust ribbon became increasingly strict.

This invention was made in view of the above points,
The object is to provide a method for manufacturing a core for a magnetic head, which allows a core of a desired shape to be easily manufactured from a magnetic material that is difficult to work with, and which can be manufactured by considering only the magnetic properties.

Next, an apparatus for carrying out the manufacturing method of the present invention will be explained.

1 is a container made of a material that can create a vacuum or gas atmosphere inside, such as stainless steel; 2 is a high-frequency heating coil housed in the container 1; 3 is located approximately in the center of the coil 2; 4 is a high-frequency oscillator connected to the coil 2, and 5 and 5' are materials with thermal conductivity such as copper or silver. The piston is made of high quality material,
Suction portions 5a and 5a' made of a magnetic material such as Vermendial are provided at the rear ends of each. Also, each opposing surface 5b, 5b' or one opposing surface 5
A core-shaped concave portion is formed in b, and opposing surfaces 5b and 5b' face each other with an appropriate distance between them, and the distance is located directly below the center of the coil 2. Reference numerals 6 and 6' designate winding frames around which drive coils 7 and 7' are wound, into which the pistons 5 and 5' are inserted through appropriate clearances. The drive coils 7, 7' are connected in series to a DC power source 9 via a switch 8. In the above embodiment, when the switch 8 is closed, the drive coils 7, 7' are energized, and the pistons 5, 5' move forward in the directions of the arrows, so that their opposing surfaces 5b, 5b' abut each other. In this case, one piston may be fixed, and only the other piston may be moved forward by the magnetic force of the drive coil, so that the opposing surfaces abut each other.

Next, a method for manufacturing a core using the above-described apparatus will be explained.

First, the sendust block 10, which is a magnetic material, is placed on the material mounting table 3, and after the material mounting table 3 is positioned at the center of the high-frequency coil 2, the container 1 is removed from the opening 1a provided in the container 1 using a vacuum pump. Exhaust the air inside and create a vacuum of 10 ^-3 Torr or higher. Next, the high frequency oscillator 4 is operated to cause current to flow through the high frequency coil 2.

Here, the sendust block 10 floats in the high-frequency coil 2 due to the repulsion between the magnetic field of the high-frequency radio waves and the magnetic field caused by the opposite direction of current generated on the surface of the sendust block due to electromagnetic induction, so the material mounting table 3 is suspended. away from the coil 2. The sendust block 10 is then melted in a floating state, but when the output of the high frequency oscillator 4 is cut off,
The melted sendust falls in a spherical shape and reaches between the opposing surfaces 5b and 5b' of the pistons 5 and 5'.
If switch 8 is turned on at this moment, piston 5,
5' move forward in the direction of the arrows and collide with each other, sandwiching and compressing the melted sendust between the opposing surfaces 5b and 5b'. The compressed sendust is rapidly cooled by the pistons 5, 5', and at the same time is formed into a core shape by the recesses in both or one of the opposing surfaces 5b, 5b'. After the molding is completed, the pistons 5, 5' are returned to their original positions and the core is taken out. Since the core is generally about 100μ thick, it can be cooled and molded in a short time, so Sendust Block 10
By supplying the molded core and taking out the molded core, it is possible to continuously manufacture the core.

Generally, when magnetic materials such as sendust are rapidly cooled, the crystal grains become smaller and the magnetic properties and mechanical properties are improved. Further, if necessary, the desired properties can be obtained by performing post-molding treatment.

The above manufacturing method is similar to the method for manufacturing amorphous amorphous, but the purpose is to obtain a core in a crystallized state rather than to create amorphous amorphous, and when sendust etc. is turned into amorphous, the magnetic properties deteriorate instead. I end up.

Although this example describes the case of sendust, materials other than sendust, such as album, etc.
It can be applied to materials with poor workability such as boroqueub and supersendust, and good results can be obtained.

In the above embodiment, the method of melting the sendust block by high frequency heating was explained, but there is another method as shown in FIG. 2.

That is, in the figure, 11 is a crucible made of a heat-resistant material such as alumina, and is provided with an argon gas inlet 11a and a nozzle 11b. Reference numeral 12 is a high frequency coil or a heater, and the high frequency coil is connected to a high frequency oscillator, and the heater is connected to a suitable power source. Reference numeral 13 is a magnetic material such as sendust, and the molten sendust falls in desired sizes as shown at 13a.

Next, to explain the manufacturing method, the sendust 13 melted by the high frequency coil or heater 12 is melted by its own weight.If it does not fall due to its own weight, argon gas is introduced from the argon gas inlet 11a, and the sendust 13 is melted by the gas pressure. The sendust 13a having a desired size is pushed out and falls down. Note that if argon gas is introduced intermittently in the above, sendust 13a of a desired size can be continuously dropped.

Similarly, the falling Sendust ribbon 13a is compressed and rapidly cooled using the press shown in FIG. 1 to obtain a core.

As described above, this invention compresses a molten magnetic material using a press with a core-shaped recess formed in at least one piston and cools it at high speed to form a core. The core can be easily manufactured from
It is possible to manufacture a core with excellent saturation magnetic flux density, and the thickness of the core can be made thin, so it is possible to manufacture a head with excellent high frequency characteristics, and it also has the effect of being able to manufacture a head that can handle high coercive force tapes. It is.

[Brief explanation of the drawing]

The figures show an apparatus for carrying out the method of manufacturing a core for a magnetic head according to the present invention, FIG. 1 is a sectional view showing a first embodiment, and FIG. 2 is a sectional view showing another embodiment. . 1... Container, 2... High frequency heating coil, 4...
High frequency oscillator, 5, 5'...Piston, 5b, 5
b'... Opposing surface provided with a recessed portion, 7, 7'... Drive coil, 11... Crucible, 12... High frequency heating coil or heater.

Claims (1)

[Claims] 1 Compressing the melted magnetic material by a press having a means for melting the magnetic material and a core-shaped recess in at least one piston, and in which at least one piston advances toward the other piston and collides with the other piston. A method of manufacturing a core for a magnetic head comprising means for rapidly cooling the core.