JPS6326808A - Magnetic head - Google Patents

Abstract

PURPOSE:To increase the leakage magnetic flux and to prevent the permeability from being deteriorated by forming a magnetic head by split pieces made of two kinds of ferrite materials with different saturation density and permeability. CONSTITUTION:The magnetic head core forming a main magnetic path consists of two split pieces 1a, 1b to form an operating gap 2. A wiring window 3 is formed in the inside of the gap 2. In utilizing the window 3, an electromagnetic conversion wire 6 is applied to the core 1. The split piece 1a is made of a ferrite material having a higher saturated magnetic flux density then that of the split piece 1b, and the split piece 1b is made by a ferrite material having a higher permeability then that for the split piece 1a. In the magnetic recording/ reproduction using a high coercive force medium, the leakage magnetic flux near the operating gap generated at recoding is increased and an excellent reproduction output is obtained without lowering the permeability.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic head used in a magnetic recording/reproducing device.

2. Description of the Related Art In recent years, magnetic heads have been widely used in the field of magnetic recording, including VTRs, audio tape recorders, floppy disks, heart disks, magnetic cards, and the like. Hereinafter, an overview of the conventional magnetic head will be explained with reference to FIGS. 3 and 4.

As shown in Fig. 4, the magnetic head core 2 forming the main ceramic
1 usually has two divided pieces 21a and 2 as shown in FIG.
1b, and an operating gap 23 is formed by the operating gap pair portion 22.

The actuating gear knob 23 may be a simple gap, but is usually filled with a magnetically insulating material such as glass to provide mechanical stability. There is a winding window 24 inside the operating gear knob 23.
The winding windows 2, 1 are formed in at least one of the divided pieces 21a, 21b constituting the magnetic helad core 21. An electromagnetic conversion winding 25 is provided on the magnetic helad core 21 using a winding member 24 .

As is well known, in magnetic recording, the surface of a recording medium made of a thin layer containing a ferromagnetic material is scanned by a recording/reproducing track 26 of a magnetic head, and the leakage magnetic flux near the working gap 23 causes the right recording magnetic field to remain unmagnetized. As a result, a residual magnetization pattern corresponding to the input signal is recorded on the recording medium. Reproduction is performed by scanning the surface of the recording medium with the recording/reproducing track 26 of the magnetic head and detecting the state of the residual magnetization.

Recently, efforts have been made to increase the coercive force of recording media in order to improve magnetic recording density. As is well known, when the coercive force of the recording medium is increased, it is necessary to increase the saturation magnetic flux density of the magnetic helad core in order to increase the leakage flux of the magnetic head for recording. The saturation magnetic flux density of Mn-Zn ferrite, which is often used as a magnetic head core material, is 4,000 to 5,000 Gauss, but studies on ternary compositions to achieve even higher saturation magnetic flux density are actively progressing. Materials with a density exceeding 6000 Gauss have been announced (for example, D, 5TOPPELS).
et al, JMMM 37 (1983) 12
3-1301 or Horiyo et al. 1985 Autumn Academic Conference of Japan Society of Applied Physics Proceedings 4a-ZE-8), applications to magnetic heads are being considered.

Problems to be Solved by the Invention However, the divided pieces 21a constituting the magnetic herad core 21
, 21b, when Mn-Zn ferrite with a high saturation magnetic flux density exceeding 6000 Gauss as described above is used, the magnetic head core 21 made of Mn'Zn ferrite with a saturation magnetic flux density of 4000 to 5000 Gauss, which has been commonly used in the past.
There is a problem in that the playback output is reduced by 20% or more compared to the above. The reason for this phenomenon, in which the reproduction output decreases even though the saturation magnetic flux density is high and is advantageous for recording, is that the magnetic permeability of the magnetic herad core made of Mn-Zn ferrite material with high saturation magnetic flux density is low. Because it is decreasing,
It is thought that the electromagnetic conversion efficiency during reproduction is reduced.

The present invention solves the above-mentioned problems of the conventional example, and makes it possible to increase the leakage magnetic flux to be advantageous for recording, and also to obtain good reproduction output without causing a decrease in magnetic permeability. It is an object of the present invention to provide such a magnetic head.

Means for solving the problems and the technical means of the present invention for solving the above problems are that the magnetic head core has an operating gap pair part and a first and second part forming a main magnetic path. It consists of two divided pieces, the first divided piece is made of a ferrite material having a higher saturation magnetic flux density than the second divided piece, and the second divided piece has a higher magnetic permeability than the first divided piece. It is made of a ferrite material having the following characteristics.

Effect of the Invention With the above configuration, the present invention can increase the leakage magnetic flux near the operating gear knob that occurs during recording in magnetic recording and reproduction using a high coercive force medium, and can obtain good reproduction output without reducing magnetic permeability. can.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a magnetic head in one embodiment of the present invention.

Magnetic helad core 1 forming the main magnetic path as shown in Figure 1
consists of two divided pieces 1a and 1b, a first and a second, and a working gap 2 made of a glass sputtered film is formed at the pass portion of the working gap. A winding window 3 is formed inside the working gap 2, and this winding window 3 is formed on at least one of the first and second divided pieces 1a11b constituting the magnetic herad core 1. On both sides of the operating gear 3 in the first and second divided pieces 1a and 1b, there is a reinforcing glass 5 for maintaining the mechanical strength of the operating gap 3 and the recording/reproducing track 4.
a and 5b are provided. An electromagnetic conversion winding 6 is provided on the magnetic helad core 1 using a winding window 3. The first divided piece 1a has a saturation magnetic flux density of 6300 Gauss.
n - Z n ferrite material, the second divided piece 1b has a saturation magnetic flux density of 5000 Gauss, and has a saturation magnetic flux density of 5000 Gauss,
The magnetic permeability is 20% higher than that of the M n -Z n ferrite material of the divided piece 1b at 5 MHz, which is the frequency band used.
It is made of high Mn-Zn ferrite material.

As a comparative example for comparing the recording and reproducing characteristics of the magnetic head of the above example, the first and second divided pieces 1a and 1b were each made of Mn-Zn ferrite with a saturation magnetic flux density of 5000 Gauss and the same magnetic permeability. The structure was otherwise the same as that of the above embodiment.

Then, using the present invention example and the comparative example, coercive force 143
The results of testing the recording and reproducing characteristics of 0 Oersted coated metal tape at a relative speed of 5.8 m/sec are as follows.
This is the passage shown in the figure. In FIG. 2, numeral 7 indicates the reproduction output of the magnetic head according to the embodiment of the present invention, and numeral 8 indicates the reproduction output of the magnetic head according to the comparative example. Note that the vertical axis in FIG. 2 is normalized based on the reproduction output voltage at 0.5 MHz of the magnetic head according to the embodiment of the present invention. As is clear from the test results shown in FIG. 2, the magnetic head according to the example of the present invention was able to obtain high reproduction output when using a high coercive force medium.

In the configuration of the embodiment of the present invention described above, various Mn-Zn ferrite materials having a saturation magnetic flux density of 5000 Gauss to 6800 Gauss are used for the first divided piece 1a, and the coercive force is 143.
The recording and reproducing characteristics of a coated metal tape of 0 oersted were tested at a relative speed of 5.8 m/sec. As a result, for materials with a saturation magnetic flux density smaller than 5800 Gauss, the difference from the output value of Comparative Example 8 shown in FIG. 2 was as small as 10%, and no superiority was recognized. Therefore, in the present invention, the first divided piece 1a has a saturation magnetic flux density of 580
It is desirable to use a Mn-Zn ferrite material with a 0 to 6800 Gauss.

In addition, in the configuration of the embodiment of the present invention, the second segment 1b is made of various Mn-Zn ferrite materials whose magnetic permeability is 10% to 40% higher than that of the first segment 1a, and a coercive force of 1430 oersted is applied. The recording and reproducing characteristics of the molded metal tape were tested at a relative speed of 5.8 m/sec. As a result, when the difference in magnetic permeability between the first and second divided pieces 1a and 1b is smaller than 15%, the difference from the output value of Comparative Example 8 shown in FIG. 2 is smaller than 10%. , no superiority was observed. Therefore, in the present invention, it is desirable to use an Mn-Zn ferrite material in which the magnetic permeability of the second divided piece 1b is 15% to 40% higher than that of the first divided piece 1a.

Further, in the configuration of the embodiment of the present invention, various Mn-Zn ferrite materials having a saturation magnetic flux density of 5000 Gauss to 6800 Gauss are used for the first divided piece 1a, and the second divided piece 1
Various MnZn ferrite materials whose saturation magnetic flux density is 200 to 1000 Gauss smaller than that of the first divided piece 1a were used for b. As a comparative example, the first divided piece 1 is made of the same M n -Z n ferrite material as the second divided piece 1 b.
A was formed. These inventive examples and comparative examples were tested for recording and reproducing characteristics on a coated metal tape with a coercive force of 11130 Oersted at a relative speed of 5.8 m/sec. As a result, the first and second divided pieces 1a and 1
When the difference in the saturation magnetic flux density of b is smaller than 500 Gauss, the difference in output from the comparative example in which only the same ~1n-Zn ferrite material is used for the first and second divided pieces 1a and 1b is 10%.
Yoshi also became smaller and his superiority was no longer recognized. Therefore, it is desirable to select the Mn-Zn ferrite material used for the first divided piece 1a and the Mn-Zn ferrite material used for the second divided piece 1b so that the difference in saturation magnetic flux density is 500 to 1000 Gauss.

Effects of the Invention As described above, according to the present invention, the magnetic herad core is composed of two divided pieces, the first and second divided pieces, and the first divided piece has a higher saturation magnetic flux density than the second divided piece. Since the second divided piece is made of a ferrite material that has a higher magnetic permeability than the first divided piece, there is no possibility of occurrence during recording during magnetic recording and reproduction using a high coercive force medium. By increasing the leakage magnetic flux near the working gap, good reproduction output can be obtained without reducing the magnetic permeability.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a magnetic head according to an embodiment of the present invention, FIG. 2 is a frequency characteristic diagram of reproduction output of an embodiment of the present invention and a comparative example, and FIGS. 3 and 4 are diagrams of a conventional magnetic head. 3 is a perspective view of the product in the middle of manufacture, and FIG. 4 is a perspective view of the product in the completed state. 1... Magnetic head core, 1a... First divided piece, 1
b...Second divided piece, 2...Operating gap, 3...
・Winding window, 4...recording/reproducing track, 5a, 5b...
・Reinforced glass ゛, 6...Winding for electromagnetic conversion. Name of agent: Patent attorney Toshio Nakao and 1 other Mx
Figure 2: 21-4 da (MHz)

Claims (4)

[Claims] (1) The magnetic head core has an operating gap pair part and consists of two divided pieces, a first and a second divided piece, forming a main magnetic path, and the first divided piece has a higher saturation magnetic flux than the second divided piece. A magnetic head characterized in that it is formed of a ferrite material having a high density, and the second divided piece is formed of a ferrite material that has a higher magnetic permeability than the first divided piece. (2) The magnetic head according to claim 1, wherein the first divided piece has a saturation magnetic flux density of 5,800 Gauss or more. (3) The magnetic head according to claim 1, wherein the magnetic permeability of the second divided piece is 15% or more higher than the magnetic permeability of the first divided piece in the operating frequency band. (4) The magnetic head according to claim 1, wherein the difference in saturation magnetic flux density between the first divided piece and the second divided piece is 500 Gauss or more.