JPH03238607A - Magnetic head - Google Patents

Abstract

PURPOSE:To prevent the generation of errors by leaking in of magnetic fluxes to a recording and reproducing head side and to prevent the degradation in margin by constituting the core part to form the closed magnetic path of an erasing head of a magnetic preferably having the lower high-frequency magnetic permeability than the high-frequency magnetic permeability of the core for recording and reproducing or having a conductive magnetic material. CONSTITUTION:The core 11 for erasing is constituted of the magnetic material having the low high-frequency magnetic permeability or the conductive magnetic material. Even if, therefore, the slight leaking magnetic flux PHIE on the medium is withdrawn by an erasing gap 7 at the time of reproducing, this magnetic flux is the high-frequency magnetic flux reproducing a data signal and consequently, the magnetic flux is attenuated by the low magnetic permeability of the core 11 for erasing at the time the magnetic flux passes the core 11 for erasing or the magnetic flux PHID is generated in the direction of disturbing the magnetic flux PHIE tending to pass the core by the eddy current generated by the electrical conductivity thereof, by which the magnetic flux is negated and the leak thereof to the core 1 side for recording and reproducing is prevented. The magnetic flux for erasing generated by the coil 10 for erasing is a DC magnetic flux and the core 11 for erasing has high magnetic permeability. The generation of the eddy current is thus obviated. The signal contg. less noises is reproduced in this way and the high reliability to eliminate the possibility of the generation of the errors and the degradation of the margin is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic head used in magnetic disk devices, flexible disk devices, and the like.

[Prior Art] Fig. 10 is a perspective view showing a conventional magnetic head disclosed in, for example, Japanese Unexamined Patent Application Publication No. 61-39910, etc. In the figure, (1) is a substantially T-shaped magnetic body (la) is the medium sliding surface of the core with respect to a magnetic disk (not shown); (1b) is the leg portion of the core; (2)
is a center core made of a magnetic material, (3) is a non-magnetic coupling material such as glass that connects the recording/reproducing core (1) and the center core (2), and (4) is a recording/reproducing material on the medium sliding surface (la). (5) is a roughly T-shaped erasing core made of magnetic material; (5a) is a medium sliding surface thereof; 5b) is the leg part of the center core (2), (6) is a non-magnetic bonding material such as glass that connects the center core (2) and the erasing core (5), and (7) is the center core (2) on the medium sliding surface (5a). ) and the erasing core (5), the erasing gap (8> is for closing the magnetic path of the recording/reproducing core (1), the center core (2), and the erasing core (5)) The back core (9) is the leg part (lb) of the recording/reproducing core (1).
)) The recording/reproducing coil wound here, (10) is the erasing coil wound around the leg part (5b) of the erasing core (5).

FIGS. 11(a) and 11(b) are schematic configuration diagrams for explaining the reproducing process of a conventional magnetic head, and FIG. 11(a) is a front view.

(b) is a bottom view, ΦR is the recording/reproducing gap (4)
ΦR represents the flow of magnetic flux of the signal reproduced by , ΦR represents the flow of magnetic flux in the recording/reproducing core (1), ΦR2 represents the flow of magnetic flux in the center core (2), and ΦR3 represents the flow of magnetic flux in the erasing core (5). It shows. ΦE represents the magnetic flux flow of the signal reproduced by the erase gap (7), and ΦE1 represents the flow of the magnetic flux of the signal reproduced by the erase gap (7).
5), ΦE2 indicates the flow of magnetic flux in the center core (2), and ΦE□ indicates the flow of magnetic flux in the recording/reproducing core (1).

Conventional magnetic heads have a recording/reproducing core (1
), a recording/reproducing head formed by a closed magnetic path consisting of a back core (8) and a center core (2), and an erasing core (5).
, an erasing head formed by a closed magnetic path consisting of a back core (8) and a center core (2) is integrally constructed.

In the above configuration, when data recorded on the medium is reproduced, a minute leakage magnetic flux on the medium is generated.

As shown in FIG. 11, the recording and reproducing core (1) and the back core (8) are drawn in by the recording and reproducing gap (4).
and the magnetic flux ΦR passing through the closed magnetic path of the center core (2), ΦR
2 closed loops are formed, and a portion becomes leakage magnetic flux ΦR1 to the erasing core (5). The magnetic flux ΦR1 passing through the recording/reproducing core (1) guides the recording/reproducing coil (9), and the reproduced data signal flows to the recording/reproducing coil (9).

At this time, if the erase gap (7) is located on the data track to be reproduced or on an adjacent track, the minute leakage magnetic flux on the medium is drawn into the erase gap (7), and the erase core ( 5), back core (8
) and the magnetic flux ΦE4 passing through the closed magnetic path of the center core (2). Φ
A closed loop of E2 is formed, and part of it is connected to the recording/reproducing core (1
) is the leakage magnetic flux ΦE.

[Problem to be solved by the invention] Since the conventional magnetic head is configured as described above,
Both the magnetic flux ΦR1 drawn by the recording/reproducing gap (4) and the leakage magnetic flux ΦE3 drawn by the erasing gap (7) pass through the recording/reproducing core (1).

These magnetic fluxes ΦR and ΦE are applied to the recording/reproducing coil (9).
The signals caused by □ are superimposed and reproduced. The data drawn in by this erase gap (7) is different from the data originally drawn in by the recording/reproduction gap (4), so it becomes noise on the playback signal, causing errors and margin reduction, and the magnetic head playback performance. There was a problem that the reliability of the system was reduced.

This invention was made in order to solve the above-mentioned problems.The magnetic flux drawn by the erase gap (7) is reduced, and this magnetic flux leaks into the recording/reproducing head side, causing errors and margin reduction. The purpose of the present invention is to obtain a high-performance magnetic head that prevents this.

[Means for Solving the Problems] The magnetic head according to the present invention has an erasing core, a magnetic body part of the center core that is coupled to the erasing core, or a magnetic body part of the back core that is coupled to the erasing core. The core portion, such as the body, which forms the closed magnetic path of the erasing head, is made of a magnetic material that has lower high-frequency magnetic permeability than the recording/reproducing core or is conductive.

[Function] In the magnetic head of the present invention, the core portion forming the closed magnetic path of the erasing head is made of a magnetic material with low high frequency magnetic permeability,
By being made of a conductive magnetic material, when the magnetic flux of the high frequency reproduction signal drawn by the erasing gap passes through this core part, for example, an eddy current is generated therein to attenuate this magnetic flux. This leakage magnetic flux is prevented from leaking into the recording/reproducing head.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is a perspective view showing an embodiment of the invention of claim 1, and FIG. 2 is a schematic configuration diagram for explaining the reproduction process of the magnetic head according to this embodiment, (a) is a front view, ) is a bottom view of Figure 0, (1) is a recording/reproducing core made of a magnetic material, (la) is its medium sliding surface, (ib) is its leg, and (2) is a core made of a magnetic material. (3) is a non-magnetic bond, (4) is a recording/reproducing gap, (6) is a non-magnetic bond, (7) is an erase gap, (8) is a back core made of a magnetic material, (9) is a recording/reproducing coil, (1
0) is an erasing coil, which is similar to the conventional example shown in FIG.

(11) is an erasing core corresponding to (5) in Fig. 10, and is made of a magnetic material with low high-frequency magnetic permeability, such as nickel zinc (NiZn) ferrite, or a conductive magnetic material, such as carbon-filled ferrite. It consists of

(lla) is its medium sliding surface, and (llb) is its leg.

Next, the operation will be explained. In this embodiment, since the erasing core (11) is made of a magnetic material with low high frequency permeability or a conductive magnetic material, the erasing gap (11) is
7), even if a small leakage magnetic flux ΦE on the medium is drawn in, the magnetic flux is the high-frequency magnetic flux that reproduced the data signal, so when passing through the erasing core (11), the erasing core (11)
) is attenuated by the low magnetic permeability of the magnetic flux ΦD, or the eddy current generated by its conductivity generates a magnetic flux ΦD in a direction that blocks the passing magnetic flux ΦE and cancels it out, as shown in Figure 2. It is possible to prevent leakage to the recording/reproducing core (1) side.

In addition, during the erasing operation, since the erasing magnetic flux generated by the erasing coil (10) is a DC magnetic flux, the erasing core (
11) has high magnetic permeability and no eddy current is generated, so the original erasing operation of the erasing head is performed in the same way as in the conventional erasing head.

3 to 6 are perspective views showing other embodiments of the invention of claim 1, respectively, and FIG. 3 is a back core (8).
For example, a non-magnetic spacer (12) made of glass or the like is provided, and the magnetic body part (81) for forming a closed magnetic path for magnetic flux for recording and reproduction and the magnetic body part (8□) for forming a closed magnetic path for magnetic flux for erasing are magnetically connected. Figure 4 shows an example separated into two.

A non-magnetic spacer (13) made of glass or the like is provided in the center core (2), and a magnetic part (2□) for forming a closed magnetic path for magnetic flux for recording and reproduction and a magnetic part (2) for forming a closed magnetic path for magnetic flux for erasing
Figure 5 shows an example in which the center core (2) and back core (8) are magnetically separated from each other by a non-magnetic spacer (
12) and (13), the magnetic body parts (2□), (8□) for forming a closed magnetic path for recording and reproducing magnetic flux and the magnetic body parts (22), (8) for forming a closed magnetic path for erasing magnetic flux are separated. □), and FIG. 6 shows an example in which the erasing gap (7) is not of the advance erasing type as in the above embodiments, but of the tunnel erasing type, and both are similar to the embodiment of FIG. 1. It has the same effect as the example.

7 to 9 are perspective views showing embodiments of the invention of claims 2 to 4, respectively, and FIG. 7 shows a recording/reproducing core (1
4) The erasing core (15) is not T-shaped as described above but E-shaped, the back core (8) is omitted, and the erasing core (15) is made of a magnetic material with low high frequency permeability or a conductive magnetic material. FIG. 8 shows an embodiment of the invention of the second claim of the present invention, which is configured by magnetically connecting the center core (16) to the recording/reproducing core (1) by a non-magnetic center spacer (13). The combined magnetic body part (16□) and erasing core (
5), and the magnetic body part (16□) magnetically coupled to the erasing core (5) is separated into a magnetic body part (16□) that is magnetically coupled to the erasing core (5). FIG. 9 shows an embodiment of the invention according to the third claim of the present invention, which is made of a conductive magnetic material. The erasing core (5) is separated into a magnetic body part (17,) magnetically coupled to the erasing core (1) and a magnetic body part (172) magnetically coupled to the erasing core (5). The magnetic body part (17□) that is magnetically coupled to is made of a magnetic material with low high frequency permeability, or
Examples of the invention according to the fourth aspect of the present invention, which are constructed of conductive magnetic materials, are shown, and both have the same effects as the above-mentioned examples.

[Effects of the Invention] As described above, according to the present invention, the erasing core, the magnetic body part of the center core that is coupled to the erasing core, or the magnetic body that is coupled to the erasing core of the back core. Department, etc.
The core part that forms the closed magnetic path of the erase head is made of a magnetic material that has lower high-frequency magnetic permeability or conductivity than the recording/reproducing core, so the magnetic flux that is drawn in by the erase gap and leaks to the recording/reproducing head is attenuated. However, it is possible to obtain a highly reliable magnetic head that can reproduce signals with less noise and is free from errors and margin reduction.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the invention as claimed in claim 1, FIG. 2 is a schematic configuration diagram for explaining the reproducing process of the magnetic head according to this embodiment, and FIG. 2(a) is a front view. , (b) is a bottom view, FIGS. 3 to 6 are perspective views showing other embodiments of the invention of claim 1, and FIGS. 7 to 9 are views of claims 2 to 4, respectively. A perspective view showing an embodiment of the invention in Section 10.
The figure is a perspective view showing a conventional magnetic head, FIG. 11 is a schematic configuration diagram for explaining the reproducing process of the conventional magnetic head, (a) is a front view, and (b) is a bottom view. In the figure, (1) is the recording/reproducing core, (la) is its medium sliding surface, (2) and (16) are the center core,
(4) is a recording/reproducing gap, (5) and (11) are erasing cores, and (5a). (lla) is its medium sliding surface, (7) is an erasing gap, and (8) and (17) are back cores. In the figures, the same reference numerals indicate the same or corresponding parts. 1 Figure 1: Recording/reproducing core 2: Center core 4: Recording/reproducing gap 11: Erasing cores la, lla: Medium sliding surface 7: Erasing gap 8: Back core 2. Figure 6 Figure 16: Center core Figure 14: Recording/reproduction core 15: Erasing cores 14a, 15a: Medium sliding surface Figure 17: Back core 10 Figure 49 Figure 1 (a) (b )

Claims (4)

[Claims] (1) A recording/reproducing core made of a magnetic material, a center core made of a magnetic material coupled to this recording/reproducing core and forming a recording/reproducing gap on the medium sliding surface between the core, and a center core made of a magnetic material that is coupled to the recording/reproducing core and forms a recording/reproducing gap on the sliding surface of the medium. , an erasing core made of a magnetic material that forms an erasing gap on the medium sliding surface between the core, and a back core made of a magnetic material for a closed magnetic path that is coupled to the recording/reproducing core, the center core, and the erasing core. 1. A magnetic head comprising: the erasing core made of a magnetic material having a lower high frequency permeability or conductivity than the recording/reproducing core. (2) a U-shaped recording/reproducing core made of a magnetic material; a center core made of a magnetic material that is coupled to the recording/reproducing core and forms a recording/reproducing gap on the medium sliding surface with one end of the core; In a magnetic head equipped with a U-shaped erasing core made of a magnetic material, which is coupled to the center core and has one end formed with an erasing gap on the medium sliding surface, the erasing core is connected to the recording/reproducing core. 1. A magnetic head characterized in that it is made of a magnetic material that has a lower high-frequency magnetic permeability or is more conductive than that of the magnetic head. (3) A recording/reproducing core made of a magnetic material, an erasing core made of a magnetic material, and a center spacer made of a non-magnetic material magnetically separate each other, one of which is coupled to the above-mentioned recording/reproducing core; a center core made of a magnetic material that forms a recording/reproducing gap on the medium sliding surface, and the other is coupled to the erasing core and forms an erasing gap on the medium sliding surface therebetween; and the recording/reproducing core. , in a magnetic head having a back core made of a magnetic material for a closed magnetic circuit coupled to a center core and an erasing core, the magnetic material portion of the center core coupled to the erasing core is connected to the recording/reproducing core. A magnetic head characterized in that it is made of a magnetic material that has low high-frequency magnetic permeability or is conductive. (4) A recording/reproducing core made of a magnetic material, a center core made of a magnetic material coupled to the recording/reproducing core and forming a recording/reproducing gap on the medium sliding surface between the core, and a center core coupled to the center core. , an erasing core made of a magnetic material that forms an erasing gap on the medium sliding surface between the core, and a back core made of a magnetic material for a closed magnetic path that is coupled to the recording/reproducing core, the center core, and the erasing core. In the magnetic head, the magnetic part of the back core that is coupled to the erasing core is made of a magnetic material that has a lower high frequency magnetic permeability or is more conductive than the recording/reproducing core. A magnetic head characterized by: