JPH0490108A - Magnetic head - Google Patents

Abstract

PURPOSE:To suppress the cracking and chipping at the front ends of projecting parts and to prevent the disturbance in reproduced waveforms by a pseudo gap by specifying the length in the track width direction of the projecting part by a core base body on the downstream side in a track traveling direction to the length smaller than the length on the projecting part on the upstream side. CONSTITUTION:The flat parts 61, 62 are formed on either of the front end of the projecting part 19 of the 1st core base body 30 consisting a 1st core half body 24 and the front end of the projecting part 32 of a 2nd core body 33 constituting a 2nd core half body 25. The length L1 of the flat part 61 is set smaller than the length L2 of the flat part 62. The relation between the width L1 of the projecting part 29 of the core base body on the upstream side in the track width direction and the width L2 of the projecting part 32 on the downstream side is set in an L1/L2=0 to 0.8, more preferably L1/L2=0 to 0.5 range. The disturbance in the reproduced waveforms by the generation of the pseudo gap is prevented in this way and the cracking and chipping of the projecting parts of the core base bodies are suppressed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a magnetic head, and in particular to a core base whose side surface facing a magnetic gap is inclined with respect to the magnetic gap plane, and 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 deposited on the side surface facing the magnetic gap.

[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. 3 is a plan view of a magnetic head as an example of this type of conventional magnetic head, and FIG. 4 is a sectional view taken along the line E-II in FIG. This magnetic head is used in a magnetic disk reproducing device and is attached to a head holder (not shown).

The reproducing head 21 is wound around a first core half 24 located on the upstream side in the track running direction A, a second core half 25 opposite thereto, and a coil groove 26 provided in the second core half 25. It mainly consists of an excitation coil 27.

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.

The second core half 25 is similar to the first core half 24.

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 corresponding to the magnetic gap 35, and a second core base body 33 made of ferrite with high magnetic permeability and having a high saturation magnetic flux density and high magnetic permeability adhered to the side surface thereof. and a second magnetic thin film 34 made of a metallic magnetic material. As shown in FIG. 3, a protrusion 29 and a first magnetic thin film 3 are provided on the first core half 24 side.
1, the protruding portion 32 on the second core half 25 side, and the second magnetic thin film 34 have a shape near the joint portion that is the magnetic gap 35.
It is almost symmetrical between the left and right sides. This magnetic gap 35 has a length of approximately 30 to 140 μm.

By the way, in the conventional magnetic head configured as described above, the protrusion 29.3 of the core base 30.33
Since the angle θ of 2 is an acute angle, the core half 24
．． When manufacturing the protruding parts 29 and 25, cracks and chips tend to occur at the tips of the protruding parts 29 and 32, resulting in poor yield.

Furthermore, in order to prevent the protruding portions of such core halves from cracking or chipping during manufacturing, a magnetic core shown in FIG. 5 has been proposed.

The magnetic core shown in FIG. 5 has a narrow flat portion 61.62 at the tip of each protrusion 59.60 of a core base 57.58 forming a core half 55.56.

However, in this magnetic head, since the flat part is parallel to the magnetic gap, depending on the length of the flat part,
This may result in a pseudo gap, which may disturb the reproduced waveform.

[Problem that the invention seeks to solve]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic head capable of suppressing cracking or chipping of the tip of a protruding portion of a core half during manufacturing of the core half, and preventing disturbance of reproduced waveform due to a pseudo gap. It is in.

[Means to solve the problem]

In order to achieve the above object, the present invention sets the length in the track width direction of the protrusion in the core half on the downstream side in the track running direction to Lls, and the length in the track width direction of the protrusion on the upstream side to L! In this case, L 2 /L 1 is set as 0 to 0.8.

As a result, the error rate caused by the pseudo gap is substantially negligible, and cracking or chipping of the tip of the protruding portion of the core half can be suppressed.

〔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;
FIG. 2 is a plan view showing another embodiment.

In the figures, the same components as those in the conventional example shown in FIGS. 3 to 5 are indicated by the same reference numerals as in FIGS. 3 to 5.

In the embodiment shown in FIG. 1, the protrusion 29 of the first core base 30 constituting the first core half 24 of the reproducing head 21 has an acute angle θ; A flat portion 62 having a length L2 in a range of 1/20 to 115 of the track width is formed at the tip of the protruding portion 32 of the second core base 33.

In the embodiment of FIG. 2, the first
Flat portions 61 and 62 are formed at both the tip of the protrusion 29 of the core base 30 and the tip of the protrusion 32 of the second core base 33 constituting the second core half 25, and the first core base The length L+ of the flat portion 61 on the 30 side is made smaller than the length L2 of the flat portion 62 on the second core base 25 side.

In both embodiments, the magnetic thin film 31.34 is applied to the entire side surface of the projection 29.32, including the flat portion 61.62, to a substantially uniform thickness, for example 50 μm.

The first core substrate 30 and the second core substrate 33 on the read head side are made of ferrite having high magnetic permeability, such as manganese-zinc ferrite or nickel-zinc ferrite. On the other hand, for the magnetic thin films 31 and 34, a crystalline alloy or an amorphous alloy having high saturation magnetic flux density and high magnetic permeability is used. Examples of such crystalline alloys include iron-aluminum-silicon alloys, iron-silicon alloys, and iron-nickel alloys. Examples of amorphous alloys include alloys consisting of 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; Or with these as main components, aluminum, germanium,
Examples include alloys to which elements such as beryllium, tin, 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 the present invention, an amorphous alloy is particularly desirable for the magnetic thin film.

Note that the angle θ of the protrusion 29 of the first core base 30 shown in FIG. 1 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.

Next, the inventors conducted various experiments and measurements on the magnetic head constructed as described above, and found that the occurrence of pseudo gaps (
The size of playback error rate) and productivity (chips and cracks at the tip of the protruding portion of the core base) were investigated. As a result, the relationship between the track running direction, the width of the protruding part of the upstream core base, and the width L2 of the protruding part of the downstream core base is determined as L+/L.
t=0-0.8, preferably Ll/L! =0~0.
It has been found that if it is set within the range of 5, no pseudo gap will occur and the productivity can be increased to a predetermined level or higher.

The samples extracted below are shown in Table 1.Table 1 shows the first embodiment of the present invention shown in FIG. 1, Sō2 shows the second embodiment shown in FIG. 2, and Nα3 shows the first conventional example shown in FIG. For example, Nα4 indicates the second conventional magnetic head shown in FIG.

Table 1 As shown in Table 1, when there is no flat part at the tip of the protruding part of the core base located on the downstream side in the truck running direction, that is, when Lt=O, productivity decreases significantly due to chips and cracks in the core base. do. Furthermore, if the length of the flat portion at the tip of the upstream protrusion is equal to or greater than the length L2 of the downstream flat portion, a pseudo gap occurs.

〔Effect of the invention〕

As described above, according to the present invention, the length Ll in the track width direction of the protrusion of the core base located on the upstream side in the track running direction, and the length Ll in the track width direction of the protrusion of the core base located on the downstream side. Since the relationship with Lx is set to L+/Lz=0.8, it is possible to prevent the disturbance of the reproduced waveform caused by the occurrence of pseudo gaps, and also to suppress cracks and chips on the protruding parts of the core base, resulting in a magnetic system with good productivity. You can get the head.

It goes without saying that the structure of the present magnetic head can be applied not only to reproducing heads but also to recording heads and recording/reproducing heads.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of the magnetic head of the present invention;
FIG. 2 is a plan view showing another embodiment of the magnetic head of the present invention, FIG. 3 is a plan view showing a conventional magnetic head, FIG. 4 is a sectional view taken along the E-I line in FIG. 3, and FIG. FIG. 2 is a plan view showing a conventional magnetic head. 21......Playback head, 24...
Brush 1 core half, 25... Second core half, 29... Protrusion, 30...
...First core substrate, 31... River first magnetic thin film,
32...Protrusion, 33...Town...Second
Core substrate, 34... Second magnetic thin film, 35
......Magnetic gear 61°62...Flat part. Figure 21...Go to playback 51. F 24... 1st] A Gakbutsu 25...O2 core meridian body 29.32...Odewaka p 30...71 core body 31... 71j 33...
・ 72 core base 34...72 pentagonal thin film 35...le air ff"v.../fu. 61.62...hanitsu

Claims (1)

[Claims] The two core halves are joined via a magnetic gap, and the two core halves have chevron-shaped protrusions on opposing sides, and the protrusions are covered with a magnetic thin film having a high saturation magnetic flux density. In the magnetic head, the length in the track width direction of the tip of the protrusion in the core half on the downstream side in the track running direction is L_2, and the tip of the protrusion in the core half on the upstream side in the track running direction is L_2. When the length in the track width direction is L_1, L_1/L_2=0
A magnetic head characterized in that the magnetic head is set to 0.8.