JPH064815A - Magnetic head - Google Patents

Abstract

PURPOSE:To prevent the generation of the failure, etc., of magnetic head cores in production process by enhancing the joining strength of the two head core half bodies of the magnetic head by molding glass. CONSTITUTION:This magnetic head is provided with the magnetic head core 10 constituting the magnetic head only in the upper part (sliding surface side) of a groove 12 for applying a winding to constitute a coil formed only on either one core half body 10b of a pair of the core half bodies 10a 10b or in the state that the glass 3 is molded in the stage before being joined to the upper part and the lower part. The part facing the groove 12 of the other head core half body 10a is constituted of molding glass parts 3, 13a beginning from the sliding surface and extending up to a range coinciding with the bottom end of the groove or further therefrom when viewed form the flank of the magnetic head.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head, and more particularly to a magnetic head in a magnetic recording / reproducing apparatus such as a VTR or FDD.

[0002]

2. Description of the Related Art FIG. 5 shows a magnetic head core 1 constituting a MIG type (metal in gap type) magnetic head as an example of a conventional magnetic head. As shown in FIG. 6, this magnetic head core 1 has a pair of high-permeability ferrites each having a narrow track for obtaining a desired track width, and a reinforcing groove for reinforcing the magnetic head core 1 by machining or the like. After forming the half bodies 1a and 1b, in the case of this example, the head core half body 1a on the left side in FIG.
The metal magnetic film 4 having a high saturation magnetic flux density is formed only on the opposing surface of the above by the thin film forming method, and the glass 3 for bonding is molded in the portion shown in FIG.

After the glass molding, one ferrite, that is, the head core half 1b, is provided with a groove 2 for winding a coil. Therefore, as shown in FIG. 6, the pair of head core halves 1a and 1b cannot have the same shape (however, with respect to the ferrite core halves 1a and 1b having the shape as shown in FIG. Although it is difficult to mold glass into the shape shown in the figure, in an actual example, a block structure in which the shape shown in FIG. On the other hand, since a glass mold is applied, one element of this block structure is expressed as shown in FIG. With the pair of ferrite core halves 1a, 1b thus obtained abutted, the two head core halves 1a, 1b are joined by remelting the glass at a high temperature. The head core 1 is formed.

FIG. 7 is a view of the winding window portion after joining as viewed from the side surface of the magnetic head. The mold glass, which has been remelted at high temperature and whose viscosity has decreased, has a winding window apex (hereinafter referred to as A-pe).
(referred to as x part), the shape of the end is determined by the contact angle determined by the wettability between the ferrite and the mold glass, and the edge becomes a hyperbolic shape due to the surface tension of the glass itself.

In FIG. 7, the lower end portion of the glass region of the head core half body 1a facing the winding groove 2 provided in the head core half body 1b has the lower end portion thereof as the head core half body 1b.
Since the glass at the lower end portion in the glass region of the head core half body 1a is above the lower end portion of the winding groove 2 in FIG. It can be said that they are not involved in joining at all.

[0006]

Generally, when the MIG type magnetic head is exposed to a high temperature, a pseudo magnetic gap easily occurs due to diffusion between the ferrite and the metal magnetic film having a high saturation magnetic flux density. As the glass, one having a low melting point is selected. In many cases, a concrete melting point of about 500 ° C. to 600 ° C. is used, and a low melting point is realized by making the glass composition mainly PbO.

However, it is known that the low melting point mold glass mainly composed of PbO is not only poor in water resistance, but its strength is extremely low as compared with the conventional high melting point mold glass. Therefore, the core strength of a magnetic head using these low melting point mold glasses is generally low, which has been a major cause of defects such as core breakage in the manufacturing process.

An object of the present invention is to solve the above-mentioned conventional problems, and to provide a magnetic head having improved core strength and preventing the occurrence of defects such as magnetic core damage in the manufacturing process. It is in.

[0009]

The magnetic head of the present invention comprises:
Provided only in the upper part (sliding surface side) of the groove for winding the coil that is formed in only one of the head core halves, or in the state where glass is molded before joining to the upper part and the lower part When the portion of the other half of the head core that faces the groove is viewed from the side of the magnetic head, it starts from the sliding surface and coincides with the lower end of this groove, or in a glass region that extends farther than this. It is characterized by being configured.

[0010]

According to the magnetic head of the present invention, not only the upper end portion of the groove provided for the winding but also the lower end portion is provided with the joining portion of the head core half body by the mold glass, and the joining area by the glass is increased. The lack of strength of the low melting point mold glass is compensated.

[0011]

The magnetic head of the present invention will be described in more detail below with reference to the embodiments shown in the drawings. FIG. 1 shows the first of the present invention.
Magnetic head core 10 in the magnetic head according to the embodiment
FIG. 6 is an enlarged view of the winding window portion 11 of FIG. In FIG. 1, 10a and 10b indicate a pair of head core halves that are joined to each other, and 12 indicates a groove formed in the head core half 10b for winding.

FIG. 2 shows the winding window portion before the two head core halves 10a and 10b shown in FIG. 1 are butted against each other, which is heat treated to melt and bond the mold glass. The magnetic head core 10 shown in 1 is obtained. In the magnetic head core 10 of the magnetic head of the first embodiment, the mold glass portion provided in the head core half body 10a has the groove 1 of the facing head core half body 10b.
2 It still extends below the lower end 12a when viewed from the sliding surface. This decompression unit is indicated by reference numeral 13a.

According to the magnetic head core 10 of the magnetic head according to the first embodiment having the above-described structure, the lower end 12a of the groove 12 of the head core half body 10b facing the mold glass portion provided on the head core half body 10a is formed. Since it extends beyond and below it, the mold glass 3 has grooves 1
2 head core halves 10a only at the upper end of 2,
The lower end portion 12a of the groove 12 is involved in the joining of the head core halves 10a and 10b, not just the joining of the 10b. This is due to the wettability between the mold glass and the ferrite, and the opposing surface at the lower end of the mold glass 3 provided on the head core half body 10a is made to be the side surface of the groove 12 in the head core half body 10b. Can be flowed. Such an increase in the number of joints means an increase in the cross section of the mold glass involved in the joint, that is, an increase in the joint strength.

Next, FIG. 3 shows the winding window portion 21 of the magnetic head core 20 in the magnetic head according to the second embodiment of the present invention.
FIG. 6 is an enlarged view of the magnetic head as viewed from the side surface. In FIG. 3, reference numerals 20a and 20b denote a pair of head core halves joined together, and 22 denotes a groove formed in the head core half 20b for winding.

FIG. 4 shows the winding window portion before the two head core halves 20a, 20b shown in FIG. 3 are butted against each other, and this is heat treated to melt and bond the mold glass. The magnetic head core 20 shown in FIG. In the magnetic head core 20 of the magnetic head of the second embodiment, the mold glass portion provided on the head core half body 20a faces the head core half body 10a of the magnetic head core 10 of the magnetic head of the first embodiment. The head core half body 20b extends downward from the lower end 22a of the groove 22 when viewed from the sliding surface.
Denote by a.

On the other hand, the head core half body 20b is provided with a mold glass portion 23b below the lower end portion 22 of the groove 22. This mold glass part 23b is arranged in advance before joining the two core halves 20a, 20b as shown in FIG. 4, like the other mold glasses 3.

According to the magnetic head core 20 in the magnetic head according to the second embodiment having the above-described structure, the lower end portion 22a of the groove 22 of the head core half body 20b facing the mold glass portion provided on the head core half body 20a is formed. Since it extends over and below it, the mold glass 3 has grooves 2
The fact that the head core halves 20a and 20b are joined not only to the upper end portion 2a but also to the lower end portion 22a is similar to the case of the first embodiment, but further below the groove 22 in the head core half body 20b. Also mold glass 2 in advance
Since 3b is provided, the mold glasses provided in each of the two head core halves 20a and 20b are mutually melted at this portion, and the mold glass breakage further involved in the joining than in the case of the first embodiment. The area can be increased.

The present invention is an example of the MIG.
Although the magnetic head of the type has been described, a single metal magnetic film or a magnetic layer in which a metal magnetic film and an insulating layer are alternately laminated is provided on a non-magnetic substrate by a thin film forming method, and further on this magnetic layer. It goes without saying that the same applies to a so-called laminated alloy film type magnetic head in which one non-magnetic substrate is joined with glass or the like and processed into a head core half body, and then a magnetic gap portion is provided and the head core is joined with glass. Nor.

Next, the bonding strength between the magnetic head according to the embodiment of the present invention and the conventional magnetic head will be concretely compared. Table 1 shows the results of comparison of the bonding strength between the magnetic head according to the conventional example and the magnetic head according to the example of the present invention. The bonding strength was measured by the evaluation machine shown in FIG. 8, and the bonding strength was simply expressed by the load when the magnetic head core broke. In FIG. 8, 30 is a load cell (load converter), 31 is a magnetic head core support,
Reference numeral 32 represents a magnetic head core pressing jig, and 33 represents a moving mechanism for applying a load. The magnetic head cores measured by this evaluation machine each have a composition of PbO-TeO ₂ -B ₂ O ₃ -Al ₂ O ₃ -ZnO-ZrO ₂ as a mold glass, transition point 355 ° C, softening point 429 ° C, Working temperature 5
What was 16 degreeC was used.

[0020]

As is clear from Table 1 above, in the case of the magnetic head according to the embodiment of the present invention, only one of the core halves has a groove for winding a coil which is a coil upper portion. It is provided on the (sliding surface side) only, or in the upper and lower parts with the glass molded before joining,
When viewed from the side of the magnetic head, the portion of the other half of the core facing the groove is formed of a glass region which starts from the sliding surface and coincides with the lower end of the groove or extends to a range farther from this. Therefore, it can be seen that the bonding strength is higher than that of the conventional example.

[0022]

As described above, according to the magnetic head of the present invention, not only the upper end portion of the groove provided for the winding but also the lower end portion of the head glass half body is joined by the mold glass. It is provided, thereby increasing the bonding area of the glass and compensating for the insufficient strength of the low melting point mold glass, so that excellent bonding strength and good recording / reproducing characteristics can be obtained, and magnetic head core breakage in the manufacturing process, etc. The occurrence of defects can also be prevented.

[Brief description of drawings]

FIG. 1 is an enlarged side view showing a winding window portion of a magnetic head core in a magnetic head according to a first embodiment of the present invention.

FIG. 2 is a side view showing a winding window portion of the magnetic head core shown in FIG. 1 before two head core halves are butted against each other.

FIG. 3 is an enlarged side view showing a winding window portion of a magnetic head core in a magnetic head according to a second embodiment of the present invention.

FIG. 4 is a side view showing the winding window portion of the magnetic head core shown in FIG. 3 before the two head core halves are butted against each other.

FIG. 5 is a perspective view showing a magnetic head core in a conventional magnetic head.

6 is a perspective view showing a state before the two head core halves are butted to each other in the conventional magnetic head core shown in FIG.

FIG. 7 is an enlarged side view showing a winding window portion in the conventional magnetic head core shown in FIG.

FIG. 8 is a structural explanatory view schematically showing an evaluator for measuring the bonding strength of the magnetic head core.

[Explanation of symbols]

 3 Mold Glass 10 Magnetic Head Core 10a Head Core Half 10b Head Core Half 11 Winding Window 12 Groove 13 Mold Glass Part Extension 20 Magnetic Head Core 20a Head Core Half 20b Head Core Half 21 Winding Window 22 Groove 23a Mold Glass Extension 23b Molded glass part below the lower end of the groove

Claims (2)

[Claims] 1. A pair of head core halves made of high-permeability ferrite is provided with a non-magnetic material as a gap spacer on the mutually facing surfaces to form a magnetic gap, and then the facing surfaces of the pair of head core halves are previously formed. A magnetic head in which the head core halves are joined to each other by melting a glass filled in a part of the head core halves for winding a coil to be formed only in one of the head core halves. The glass is provided on the upper part (sliding surface side) of the groove in a state before being bonded, and when the part of the other head core half facing the groove is viewed from the side of the magnetic head, it slides. A magnetic head comprising a glass region starting from a moving surface and extending to a range farther than a lower end portion of the groove. 2. A pair of head core halves made of high-permeability ferrite is provided with a non-magnetic material as a gap spacer on the mutually facing surfaces to form a magnetic gap, and then the facing surfaces of the pair of head core halves are previously formed. A magnetic head in which the head core halves are connected to each other by melting the glass filled in a part of the head core halves for winding a coil to be formed only in one of the head core halves. When the glass is provided on the upper part (sliding surface side) and the lower part of the groove before molding, the part of the other half of the head core facing the groove is viewed from the side of the magnetic head. A magnetic head comprising a glass region starting from the sliding surface and extending to a range farther from the lower end of the groove.