JPH0481803B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic head, and particularly to a core base whose side surface facing a magnetic gap is inclined with respect to the magnetic gap surface, and a core base of the core base. The present invention relates to a magnetic head having a core half having a magnetic thin film made of a magnetic material having a high saturation magnetic flux density and coated on the side surface facing the magnetic gap.

[Conventional technology]

With the increasing density of magnetic recording, the coercive force of magnetic recording media has increased, and as a magnetic head capable of recording on this magnetic recording medium, at least the portion facing the magnetic gap is made of a magnetic material having a high saturation magnetic flux density. Development of magnetic heads is progressing.

FIG. 5 is a plan view of a composite magnetic head as an example of this type of conventional magnetic head, and FIG.
FIG. This composite magnetic head is used in a magnetic disk recording/reproducing device, and includes a recording/reproducing head 21, an erasing head 22,
It is mainly composed of a non-magnetic material 23 for preventing magnetic influence between both magnetic heads. These units are attached to a head holder (not shown) so that the recording/reproducing head 21 is disposed on the upstream side in the running direction of the magnetic recording medium (magnetic disk), and the erasing head 22 is disposed on the downstream side.

The recording/reproducing head 21 includes a first core half 24 and
It mainly consists of a second core half 25 facing the second core half 25 and an excitation coil 27 wound around a coil groove 26 provided in the first core half 24 . A reinforcing layer 28 is made of a non-magnetic material such as glass, and is provided near the joint between the first core half 24 and the second core half 25.

The first core half 24 includes a first core base body 30 having a chevron-shaped protrusion 29 approximately at the center of the side surface facing the magnetic gap 35, and a first
It is composed of a magnetic thin film 31.

The first core base 30 is made of, for example, manganese.
A ferrite with high magnetic permeability, such as zinc ferrite or nickel-zinc ferrite, is used.
On the other hand, for the first magnetic thin film 31, a crystalline alloy or an amorphous alloy having high saturation magnetic flux density and high magnetic permeability is used. As this crystalline alloy, iron-
Examples include aluminum-silicon alloys, iron-silicon alloys, and iron-nickel alloys. The amorphous alloy may include one or more elements selected from the group of iron, nickel, and cobalt, and one or more elements selected from the group of phosphorus, carbon, boron, and silicon.
Alloys consisting of more than one type of element, or alloys containing these as main components with addition of elements such as aluminum, germanium, beryllium, tin, molybdenum, indium, tungsten, titanium, manganese, chromium, zirconium, hafnium, niobium, or cobalt. , alloys containing zirconium as a main component and the above-mentioned additional elements.

Like the first core half 24, the second core half 25 also includes a second core base 33 made of ferrite with high magnetic permeability and having a chevron-shaped protrusion 32 at approximately the center of the side surface facing the magnetic gap 35; and a second magnetic thin film 34 made of a metallic magnetic material having high saturation magnetic flux density and high magnetic permeability, which is adhered to the side surface of the magnet. As shown in FIG. 5, the first core half 2
4 side protrusion 29 and first magnetic thin film 31;
The protrusion 32 on the second core half 25 side and the second magnetic thin film 34 are approximately symmetrical in shape in the vicinity of the joint with the magnetic gap 35 interposed therebetween. This magnetic gap 35 has a length of approximately 100 to 140 μm.

On the other hand, the erase head 22 has a first core half 36
, a second core half 37 facing the second core half 37 , and an excitation coil 39 wound around a coil groove 38 provided in the second core half 37 . A reinforcing layer 40 is made of a non-magnetic material such as glass, and is provided near the joint between the first core half 36 and the second core half 37.

The first core half 36 includes a first core base body 43 made of high magnetic permeability ferrite and having two chevron-shaped protrusions 42 at a predetermined interval on the side surface facing the magnetic gap 41; It is composed of a first magnetic thin film 44 made of a metallic magnetic material having a high saturation magnetic flux density and high magnetic permeability.

Similarly to the first core half 36, the second core half 37 is made of high magnetic permeability ferrite and has two chevron-shaped protrusions 45 at a predetermined distance on the side facing the magnetic gap 41. A base body 46;
It is comprised of a second magnetic thin film 47 made of a metallic magnetic material having high saturation magnetic flux density and high magnetic permeability, which is adhered to the side surface thereof. Therefore, as shown in FIG. 5, the protrusion 42 and the first magnetic thin film 44 on the first core half 36 side and the protrusion 45 and the second magnetic thin film 47 on the second core half 37 side are bonded. The shape of the vicinity of the part is approximately symmetrical with respect to the magnetic gap 35.

The magnetic gap 35 of the recording/reproducing head 21 and the two magnetic gaps 41 of the erasing head 22 have a positional relationship as shown in FIG. 5, and recording tracks are formed on the magnetic recording medium by the recording/reproducing head 21. Immediately thereafter, both ends of the recording track are partially erased by the erasing head 22 to regulate the track width.

Note that the angle θ of the protruding portion 29 of the first core base 30 shown in FIG. 5 is set to an acute angle of about 45° to 90°, that is, a relatively small angle. The same applies to the angle of the protrusion 32 of the second core base 33 of the second core half 25.

By the way, the conventional composite magnetic head configured as described above has the core bases 30, 3 as described above.
Since the angles of the protrusions 29 and 32 of No. 3 are acute, the tips of the protrusions 29 and 32 are likely to be cracked and chipped during the production of the core halves 24 and 25, resulting in poor yield. There is a problem.

In addition, in order to prevent cracks and chips during the production of the protruding portion of the core half, conventionally,
Magnetic cores shown in FIGS. 7 and 8 have been proposed.

The magnetic core shown in FIG. 7 is provided with a minute protrusion 53 having a substantially rectangular cross section at the tip of a protrusion 52 of a core base 51 constituting a core half body 50, and a protrusion including this protrusion 23. A magnetic thin film 54 equivalent to the magnetic thin films 31 and 34 shown in FIG. However, in the case of a magnetic head configured in this way, since the protrusion 53 is minute, it is weak in strength, and the entire protrusion 53 may break off from the protrusion 53. Therefore, there is a problem that it is difficult to improve the yield.

The magnetic core shown in FIG. 8 has core halves 55 and 56.
Flat parts 61, 62 having a relatively large width dimension t are formed at the tops of the protruding parts 59, 60 of the core bases 57, 58 forming the core bases 57, 58, respectively.
The magnetic thin film formed on the surface of 62 is set to be significantly thinner than the magnetic thin films 63 and 64 formed on other parts. Note that 65 is a magnetic gap. However, the magnetic head constructed in this way is magnetically saturated near the magnetic gap 65 at the tip of each of the projections 59 and 60, and cannot be used as a magnetic head after all.

[Problem that the invention seeks to solve]

An object of the present invention is to eliminate the drawbacks of the prior art described above, ensure good magnetic properties, and prevent cracks or chips at the tip of the protruding part of the core half when manufacturing the core half. The object of the present invention is to provide a magnetic head that can suppress the

[Means for solving problems]

In order to achieve this object, the present invention has a configuration in which an extremely narrow flat portion is provided at the tip of the protruding portion that forms the core half.

〔Example〕

Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 is a plan view showing an embodiment of the magnetic head of the present invention, and FIG. 2 is a sectional view taken along the line of FIG. 1.

These FIGS. 1 and 2 are drawn corresponding to the aforementioned FIGS. 5 and 6, and show a composite magnetic head having a recording/reproducing head and an erasing head.

In addition, in these figures, the fifth and sixth
Components equivalent to those in the figure are designated by the same reference numerals. In this embodiment, as shown in FIG. 1, a figurative magnetic gap is formed at the tip of the protrusion 29 of the first core base 30 that constitutes the first core half 24 of the recording/reproducing head 21. A flat portion 70 is formed with an extremely narrow width, for example, a width of about 15 μm. Further, the tip of the protrusion 32 of the second core base 33 constituting the second core half 25 of the recording/reproducing head 21, the tip of the protrusion 42 of the first core base 43 of the erasing head 22, and the second core Extremely narrow flat portions 71, 72, and 73, which are similar to the flat portion 70 described above, are formed at the tip of the protruding portion of the base body 46, respectively.

Note that the magnetic thin films 31, 34, 44, 47 have protruding parts 29, 3 including flat parts 70, 71, 72, 73.
2, 42, and 45 to have a substantially uniform thickness, for example, the same thickness as shown in FIGS. 5 and 6 described above.

The other configurations are the same as those shown in FIGS. 5 and 6 described above.

First core half 2 of the recording/reproducing head 21 described above
4, the first core base 30, the second core half 25,
Core base 33, first core half 3 of erase head 22
6 first core base 43, second core half 37
In the core base body 46, for example, as shown in FIG.
The hatched portions are cut to form numbers 0, 71, 72, and 73.

In the embodiment configured in this way, flat portions 70, 71, 72 with a width of 15 μm,
73 respectively, the fourth core half body 24, 25, 36, 37 is formed.
As illustrated in the figure, the number of cracks and chips of 2 μm or more per 1 cm length is suppressed to about 1/3 compared to the conventional case shown in FIGS. 5 and 6, in which no flat portion is formed. Further, the width of the flat portions 70, 71, 72, and 73 is approximately 15 μm, which is a dimension that does not form a similar magnetic gap, so that good magnetic properties can be ensured.

〔Effect of the invention〕

Since the magnetic head of the present invention is constructed as described above, the characteristics of the magnetic thin film having a high saturation magnetic flux density can be fully exhibited, and good magnetic properties can be obtained. This has the effect of suppressing cracking and chipping of the tip of the protruding portion of the core half, and improving yield compared to the conventional method.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the magnetic head of the present invention, FIG. 2 is a sectional view taken along the line of FIG. An explanatory diagram showing an example of the manufacturing method, FIG.
An explanatory diagram illustrating the extent of cracks and chips that occur in the core base of the core half that constitutes the magnetic head shown in the figure,
FIG. 5 is a plan view of a composite magnetic head as an example of a conventional magnetic head, FIG. 6 is a sectional view taken along the line A--I in FIG. 5, and FIGS. FIG. 3 is a cross-sectional view of a main part showing another example of a conventional body. 21... Recording/reproducing head, 22... Erasing head, 24, 36... First core half, 25, 37...
...Second... Core half, 29, 32, 42, 45...
...Protrusion, 30, 43...First core base, 31,
44...First magnetic thin film, 33,46...Second core base, 34,47...Second magnetic thin film, 35,41
...Magnetic gap, 70, 71, 72, 73...
Flat part, 74... Ferrite block, 75...
side.

Claims (1)

[Claims] 1. A magnetic head formed by joining two core halves through a magnetic gap, in which at least one of the two core halves has a chevron-shaped protrusion on the side surface facing the other core half. What is claimed is: 1. A magnetic head comprising: a magnetic thin film having a high saturation magnetic flux density deposited on a protrusion; characterized in that an extremely narrow flat portion is formed at the tip of the protrusion.