JPS62146415A - Magnetic head - Google Patents

Abstract

PURPOSE:To increase the minimum on-track width at the time of the maximum off-track and to improve recording and reproducing characteristics by setting up the inclination of a projection part of an erasing core base to a value larger than the inclination of a projection part of a recording/reproducing core. CONSTITUTION:The angle theta1 of inclination of the projection part 29 of the 1st core base 30 on the recording and reproducing side and the projection part 32 of the 2nd core base 33 are formed so as to be 120 deg.. On the other hand, the projection part 42 of the 1st core base 43 on the erasing side and the projection part 45 of the 2nd core base 46 are formed so as to be 60 deg.. To increase the minimum on-track width at the time of the maximum off-track, the tolerance of tunnel width of a recording and reproducing gap 35 and an erasing gap 41 should be reduced, so that the angle of inclination of the projection parts should be sharply formed. Thereby, the inclination of the projection part on the erasing side can be increased as mentioned above, the minimum on-track width can be increased at the maximum off-track and the recording and reproducing characteristics can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic head, and particularly relates to a recording/reproducing core having a recording/reproducing head gap, and an overflow of a recording trajectory recorded by the recording/reproducing head gap. The present invention relates to an improvement in a magnetic head provided with an erasing core having an erasing head gap for erasing a portion.

[Conventional technology]

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

FIG. 4 is a plan view of a composite magnetic head as an example of this kind of conventional magnetic head, and FIG. 5 is a sectional view taken along the line E-II in FIG. This composite magnetic head is used in a magnetic disk recording/reproducing device, and mainly consists of a recording/reproducing head 21, an erasing head 22, and a non-magnetic material 23 for preventing magnetic influence between the two magnetic heads. It is configured. These integrated bodies form 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.
can be attached to.

The recording/reproducing head 21 is mainly composed of a first core half 24, a second core half 25 opposing the first core half 24, and an excitation coil 27 that is S'A'd into a coil groove 26 provided in the first core half 24. has been done. A reinforcing layer 28 made of a non-magnetic material such as glass is provided near the joint between the first core half 24 and the second core half 25.

The first core half 24 has a chevron-shaped protrusion 29 approximately in the center of the side surface facing the magnetic gap 35, and includes a first core base 30 made of ferrite with high magnetic permeability and a high It is composed of a first magnetic thin film 31 made of a metallic magnetic material having a saturation magnetic flux density and high magnetic permeability.

Similarly to the first core half 24, the second core half 25 also has a chevron-shaped protrusion 3 approximately in the center of the side surface corresponding to the magnetic gap 35.
a second core body 33 made of ferrite with high magnetic permeability and a second magnetic thin film 3 made of a metallic magnetic material with high saturation magnetic flux density and high magnetic permeability adhered to the side surface thereof;
It is composed of 4. As shown in FIG. 4, a protrusion 29 and a first magnetic thin film 31 are provided on the first core half 24 side,
The shape of the protruding portion 32 and the second magnetic thin film 34 of the 25 second core halves in the vicinity of the joint portion is approximately symmetrical with respect to the magnetic gap 35 . This magnetic gap 35 has a length of about 100 to 140 μm.

On the other hand, the erasing head 22 mainly consists of a first core half 36, a second core half 37 opposite thereto, and an excitation coil 39 mounted in a coil groove 38 provided in the second core half 37. It is configured. Reference numeral 40 indicates a reinforcing layer 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 body 36 includes a first core base body 43 made of ferrite with a high i3 +H ratio and having two chevron-shaped protrusions 42 at a predetermined interval on the side surface facing the magnetic gap 41.
and a first magnetic thin film 44 made of a metallic magnetic material having high saturation magnetic flux density and high magnetic permeability, which is adhered to the side surface thereof.

Similarly to the first core half, the second core half 37 also has a second core base made of ferrite with a high ratio of 33 m and has two chevron-shaped protrusions 45 at a predetermined interval on the side facing the magnetic gap 41. 46, and a second metal magnetic material having high saturation magnetic flux density and high magnetic permeability adhered to the side surface thereof.
It is composed of a magnetic thin film 47. Therefore, as shown in FIG. 4, the protrusion 42 and the first magnetic fill film 44 of the 36 first core halves are bonded to the protrusion 45 and the second magnetic thin film 47 of the second core half 37. The shape of the area near the portion is symmetrical with respect to the magnetic gap 35.

Magnetic gap 35 of recording/reproducing head 21 and erasing head 2
The two magnetic gaps 41 of No. 2 have a positional relationship as shown in FIG. Parts of both ends are erased to regulate the track width.

Next, the manufacturing process of this magnetic head will be explained. 6th
As shown in the figure, a pair of parallel grooves 8.8 are provided close to each other on one side of the ferrite block 7 constituting the core base 5,
A protrusion 9 having a sharp tip (top) is formed between the grooves 8 . Next, on the surface on which the grooves 8 and protrusions 9 are formed, a magnetic thin film 6 made of a magnetic material with high saturation magnetic flux density and high permeability is uniformly formed using a thin film manufacturing technique such as strip deposition or sputtering.

Next, as shown in FIG. 7, a relatively thick reinforcing layer 10 made of a non-magnetic material such as glass is provided on the magnetic thin film 6, and then polished to the position shown by the dashed line in the same figure. This state is shown in FIGS. 8 and 9, where a portion of the magnetic thin film 6 on the tip of the protrusion 9 is polished flat to form a flat portion 11.

In some of the blocks thus formed, coil grooves 12 are formed by cutting to a predetermined depth in a direction perpendicular to the protrusions 9, as shown in FIG.

Next, the coil groove 12 was formed, and the block with the coil groove 12 and the block without the coil groove 12 (see IQ in FIG. 9) were bonded together by glass bonding, with the reinforcing layers 10 facing each other as shown in FIG. Join together.

Erasing heads 22 are formed in the same manner, and the side surfaces of the blocks that do not form the coil grooves 26 and 38 of each head are cut, and a non-magnetic material 23 is sandwiched between each head and bonded with resin.

This is sliced along the dashed line shown in the 12th cabinet to create a magnetic head device.

On the other hand, in this type of magnetic recording/reproducing device, there are precision in positioning of the device and temperature/humidity expansion of the medium, and furthermore, accuracy in the width of the gap 35 of the recording/reproducing head and the gap 41 of the erasing head of the magnetic head device. Each track width is determined by the positional accuracy of . The conditions to be determined are the worst condition: the il+ recording/reproducing head does not read adjacent tracks, and (2) the self-recording width is greater than or equal to the erase tunnel width. (3) Do not erase your own tracks during self-recording. No. 3
Two conditions must be met. As shown in FIG. 13, the width A tolerance of the recording/reproducing gap 35 is ±a, the width B tolerance of the erasing head gap 41 is ±b, and the tunnel width tolerance ±d.
, if both the recording/reproducing gap width and the erasing gap width are ±e, the track pitch is P, and the amount of off-track is T, then from the above conditions, ■ T ≦ B −b−d−・−+3+, and the minimum on value at the maximum off track time. Track radiation Ts From (1) and (2) -P-T D=A (a+d+2e) =P-T-(a+d+2e) -T-a = P -2T -a -d -2e -------
--(51 Therefore, in order to increase the minimum on-track width Ts at maximum off-track time, the recording/reproducing gap 35
It is necessary to make the width tolerance a of the erasing gap 41 and the tunnel width tolerance d of the erasing gap 41 as small as possible.

However, in the conventional magnetic head, the inclination angle of the protruding part of the erasing core base is the same as that of the protruding part of the recording/reproducing core base, and the inclination angle is relatively large. There was a limit to how small it could be.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic head that has improved gap width and track width dimensions and is excellent in improving the recording and reproducing characteristics of a magnetic head device.

[Means to solve the problem]

In order to achieve the above object, the slope of the protruding portion of the core base body is made steep. In other words, when polishing is used to determine the track width, when the height of the irregularities on the plane of the polished surface is t, the influence on the track width accuracy is t sin
It was found that θ/2 (θ: angle of inclination of the protrusion). The present inventors generally found that from the viewpoint of recording/reproducing characteristics, it is good when the inclination angle e of the protrusion of the core base on the recording/reproducing head side is 90 to 120 degrees, and filed an application earlier (Special Patent Application). (Gan Sho 59-194872).

Therefore, in the present invention, the recording and reproducing side maintains good recording and reproducing characteristics, and the inclination angle of the protrusion on the erasing side is made larger than that on the recording and reproducing side, thereby improving the dimensional accuracy compared to the recording and reproducing side. The minimum on-track width when off-track is increased to improve recording and reproducing characteristics.

〔Example〕

Hereinafter, the present invention will be described in detail based on the drawings.

FIG. 1 is a plan view of a composite magnetic head showing an embodiment of the present invention. In FIG. 1, the protrusion 29 of the first core base 30 and the protrusion 32 of the second core base 33 on the recording/reproducing side
The inclination angle θ1 of each is set to 120°. Furthermore, the protrusion 42 of the first core base 43 on the erasing side and the second
The inclination angle θ2 of the protrusions 45 of the core base 46 is 60, respectively.
' is formed.

Except for the structure having the core base body having such an inclination angle, it is substantially the same as the conventional magnetic head shown in FIG. The two-core base 33, the first core base 43, and the second core base 46 are all made of ferrite having high magnetic permeability, such as manganese-zinc ferrite or nickel-zinc ferrite.

A metallic magnetic material having a high saturation magnetic flux density and a high i3 magnetic rate is deposited on each of the core substrates. Crystalline alloys and amorphous alloys are used as such metal magnetic materials. This crystalline alloy includes iron-aluminum-silicon alloy,
These include iron-silicon alloys and iron-nickel alloys. In addition, as an amorphous alloy, one or more elements selected from the group of iron, nickel, and cobalt, phosphorus,
An alloy consisting of one or more MjR elements from the group of carbon, boron, and silicon, or an alloy consisting of these as main components such as aluminum, germanium, helium, tin,
There are alloys to which elements such as molybdenum, indium, tungsten, titanium, manganese, chromium, zirconium, hafnium, and niobium are added, and alloys containing cobalt and zirconium as main components and the above-mentioned additional elements.

In Figure 1, the recording/reproducing side and the erasing side are each 120
", 60 degrees, in normal processing, the width A of the erasing gap 35 shown in FIG. d=2.5 μm. Therefore, the on-track width at maximum off-track is 5% compared to a conventional magnetic head (120° tilt angle on both the recording/reproducing side and the erasing side).
increased.

FIG. 2 shows a composite magnetic head showing another embodiment of the present invention, in which the interval between the recording/reproducing gap 35 and the erasing gap 44 is made as small as possible in order to be installed in a small floppy disk device. This is what I did. That is, in FIG. 2, as shown in FIG. 3, as the block in which the winding window of the erasure core is not provided, a metal magnetic thin film having a high saturation magnetic flux density and a high i3 magnetic flux is formed on a thin flat substrate 7. A block coated with 6 is used. The inclination angle θ of the protrusion 29 of the first core base 33 and the protrusion 32 of the second core base 33 is 120, respectively.
The protrusion 4 of the second core body 4.6 on the erase side is formed at
The inclination angle θ4 of No. 5 is set to 60°. In the embodiment shown in FIG. 2, the constituent materials of the core substrate and the metallic magnetic material with high saturation magnetic flux density and high magnetic permeability deposited on the core substrate are the same as those in FIG. 1.

In this embodiment as well, the same effects as in the case of the magnetic head shown in FIG. 1 can be achieved.

In the present invention, the inclination angle of the protrusion of the erasing core base is
The angle of inclination is greater than that of the protrusion of the recording/reproducing core base (by doing so, the dimensional accuracy of the gap width and track width can be improved).

〔Effect of the invention〕

As described above, according to the present invention, since the inclination of the core base of the erasing head is made larger than that on the recording/reproducing head side, the precision of the track width is improved and the minimum on-track width is increased.
High performance of the magnetic head can be achieved.

[Brief explanation of drawings]

FIG. 1 is a plan view showing one embodiment of the magnetic head according to the present invention, FIG. 2 is a plan view showing another embodiment of the magnetic head according to the present invention, and FIG. 3 is a block used in FIG. 2. FIG. 4 is a plan view of a conventional composite magnetic head, FIG. 5 is a sectional view taken along the E-I line in FIG. 4, and FIGS.
Figure 2 shows the manufacturing process of the magnetic head, Figure 6 is an explanatory diagram of the process of forming grooves in a ferrite block and forming a magnetic thin film on one side, and Figure 7 shows the process of forming a magnetic thin film on the magnetic thin film of Figure 6. FIG. 8 is an explanatory diagram of the process of cutting along the dashed line in FIG. 7, FIG. 9 is a perspective view of the block formed in the step of FIG. 8, and FIG. 9
Fig. 11 is a state diagram in which the block shown in Fig. 9 is joined to the block shown in Fig. 10, and Fig. 12 is a state diagram in which the block shown in Fig. 11 is joined with a coil groove. FIG. 13 is an explanatory diagram showing the tolerances of the magnetic head. 21...Recording/reproducing head, 22...Erasing head, 23...Nonmagnetic material, 24...
...First core half, 25...Second core half, 26...Coil groove, 27...Exciting coil, 28... Reinforcement layer, 29...
... protrusion, 30... first core base,
31...First magnetic thin film, 32...Protrusion, 33...Second core base, 34...
...Second magnetic thin film, 35...Magnetic gap,
36...First core half, 37...Second
Core half, 3 days...Coil groove, 39...
... Excitation coil, 40 ... Reinforcement layer, 41
...Magnetic gap, 42...Protrusion, 43...First core base, 44...
・First magnetic thin film, 45... Protrusion, 4
6...Second core substrate, 47...Second magnetic thin film. 4 stones 1st figure 29. 32, 42, 45: overhang 2nd figure 5th figure 6? Figure 7 Figure 8 Figure 9 Cause/l Figure 70 Figure 1/Figure?

Claims (1)

[Claims] (1) A magnetic head provided with a recording/reproducing core having a recording/reproducing head gap and an erasing core having an erasing head gap for erasing the protruding portion of the recording trajectory recorded by the recording/reproducing head gap. , the recording/reproducing core and the erasing core are each formed by joining two core halves through a magnetic gap, and each has a chevron-shaped protrusion on an opposing side surface of a core base constituting the two core halves. and a high saturation magnetic flux density magnetic material is coated on the protrusions, characterized in that the inclination of the protrusion of the erasing core base is greater than the inclination of the protrusion of the recording/reproducing core base. That's a magnetic head.