JPH097114A - Magnetic head - Google Patents

Abstract

PURPOSE: To provide a magnetic head constituted of a small-sized coil and with a high S/N ratio. CONSTITUTION: This head is provided with a central core 12 and a first side chip 13 as a recording/reproducing head magnetic core half body and a second side chip 14 as an erase head magnetic core half body integrally attached to both side surfaces of one end of the central core. The magnetic head 10 is constituted of a recording/reproducing coil 15 and an erase coil 16 provided in the periphery of the first, second side chips 13, 14 and a back core 18 attached to the central core, the other end sides of the first side chip and the second side chip, and is constituted so that the back core 18 is formed into a T type.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head for a magnetic recording medium such as a floppy disk, and more particularly to a magnetic head having a back core behind a head core.

[0002]

2. Description of the Related Art Conventionally, a bulk type magnetic head for a 3.5 inch floppy disk is constructed as shown in FIG. That is, in FIG. 14, the magnetic head 1 includes a recording / reproducing head including the center core 3 and the side chips 4 by attaching the center core 3 and the two side chips 4 and 5 to the head core 2.
It is composed of a center core 3 and an erasing head using a side chip 5.

In the case of the head core 2, the lower surface of the head core 2 is formed as a sliding surface 2a with the floppy disk, and an air escape groove 2b is formed along the center of the lower surface. The center core 3 has a first side chip 4 as a magnetic core half of a recording / reproducing head on both sides of the lower end thereof.
Also, the lower ends of the second side chips 5 as the magnetic core halves of the erasing head are integrally formed.

A recording / reproducing coil 6 and an erasing coil 7 are fitted on the upper portions of the two side chips 4 and 5, respectively. These coils 6 and 7 are configured by being wound around the coil winding portions 8a and 8b of the bobbin 8 which are integrally formed, and the winding ends of the coils 6 and 7 are arranged on the bobbin 8. Are connected to terminals 8c and 8d provided on the. Then, by inserting the bobbin 8 into the head core 2, the coils 6 and 7 are fitted to the side chips 4 and 5, respectively.

Further, in FIG. 15, a back core 9 is arranged above the coils 6 and 7. The back core 9 is a so-called E-shaped core, and the three projecting portions extending in parallel to each other, that is, the central projecting portion 9a and the side surfaces of the projecting portions 9b and 9c on both sides are respectively the center core 3, the side chip 4, and the side chip 4. A closed magnetic circuit is configured by being adhered to the side surface of the upper part of 5.

According to the magnetic head 1 having the above-described structure, the magnetic disk (not shown) is moved as indicated by an arrow X in FIG. At, the signal already recorded on the magnetic disk is erased, and then a new signal is recorded by the recording / reproducing head.

[0007]

However, in the magnetic head 1 having such a structure, the back core 9 is
It is an E-shaped core, and each protrusion 9a, 9b, 9c is
They are adhered along the upper portions of the center core 3, side chips 4 and 5, respectively. Therefore, as shown in FIG. 16, since the magnetic fluxes passing through the center core 3 and the side chips 4 and 5 have the same amount, the magnetic resistances A, B and C of the center core 3 and the side chips 4 and 5 become the same. . Therefore, the magnetic flux from the outside, for example, the magnetic flux as noise from a CRT (cathode ray tube) used as a display of a personal computer or the like has a relatively large amount of interlinkage with the coils 6 and 7, and therefore the magnetic head 1 However, there is a problem that the S / N ratio of the output signal of is decreased.

Inside the hollow portions of the coils 6 and 7, the side chips 4 and 5 and the protruding portion 9 of the back core 9 are respectively provided.
Since b and 9c will be inserted, each coil 6,
The inner diameter of coil 7 is relatively large. Therefore,
Since the coils 6 and 7 themselves also become large, there is a problem that the amount of linkage with the external magnetic flux increases and the SN ratio of the output signal decreases.

In view of the above points, an object of the present invention is to provide a magnetic head in which each coil is made compact and the SN ratio is improved.

[0010]

According to the present invention, the above object is to provide a center core and a first side chip as a magnetic core half for a read / write head, which is integrally attached to both side surfaces of one end of the center core. And a second side chip as a magnetic core half for an erasing head, a recording / reproducing coil and an erasing coil provided around the first and second side chips, the center core, the first side chip and the first side chip. A back core attached to the other end of the second side chip, wherein the back core includes a first portion extending in one direction and a second portion extending substantially vertically from the vicinity of the center of the first portion. This is achieved by a magnetic head formed in a T shape consisting of a part and a part.

[0011]

According to the above construction, the back core is formed as a T-shaped core consisting of the first portion extending in one direction and the second portion extending substantially vertically from the vicinity of the center of the first portion. . Therefore, along the upper side surface of the center core,
The central protruding portion of the back core, which is the second portion, is adhered, and only the opposite ends of the back core are in contact with the side surfaces of the upper ends of the side chips. Therefore, the magnetic resistance in the side chip is larger than that in the center core, so that noise due to the external magnetic flux is reduced. Further, since only the side chips are fitted in the hollow portions of the coils and the protruding portions of the back core are not fitted, the hollow portions of the coils are formed small, that is, the inner diameters of the coils are formed small. become.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to FIGS. In addition, since the Examples described below are preferred specific examples of the present invention, various technically preferable limitations are given. However, the scope of the present invention particularly limits the present invention in the following description. The embodiment is not limited to these embodiments unless otherwise stated.

FIG. 1 shows a first embodiment of a magnetic head according to the present invention. In FIG. 1, the magnetic head 10
Is configured by attaching the center core 12 and the side chips 13 and 14 to the head core 11.

The head core 11, the air escape groove 11b, the center core 12, the second side chip 14, etc. are substantially the same as the configuration described in FIG.

Also, the two side chips 13 and 14 described above are provided.
A recording / reproducing coil 15 and an erasing coil 16 are respectively fitted on the upper part of the. These coils 15, 16
Is a coil winding portion 17 of the bobbin 17 formed integrally.
The winding ends of the coils 15 and 16 are connected to terminals 17c and 17d provided on the bobbin 17, respectively. Then, by inserting the bobbin 17 into the head core 11, the coils 15 and 16 are inserted into the side chip 1 respectively.
3, 14 will be fitted.

Further, in FIG. 1, a back core 18 is arranged above the coils 15 and 16. The back core 18 magnetically connects the upper ends of the center core 12 and the two side chips 13 and 14.

The back core 18 is a so-called T-shaped core, and has a first portion that extends horizontally in FIG. 2 and a protruding portion 18a that serves as a second portion that extends downward from the center of the first portion. Side surfaces of the side chip 13 are adhered along the upper end surface of the center core 12, and the side surfaces of both ends are
A closed magnetic circuit is configured by being bonded to the end surface of the upper end of 14.

Therefore, when the magnetic disk (not shown) is run as shown by the arrow X in FIG. 1, the erasing head by the center core 12 and the side chip 14 is already on the magnetic disk. The signal recorded on the magnetic disk is erased, and then the center core 1
A new signal is recorded by the recording / reproducing head composed of 2 and the side chip 13.

Since the back core 18 is a T-shaped core, only the side chips 13 and 14 are fitted in the hollow portions of the coils 15 and 16, respectively, and the back core 1
The protruding portion of 8 is not fitted. Therefore, as shown in FIG.
The magnetic flux passing through the center core 12 receives the side chips 13,
The magnetic resistance D of the center core 12 is smaller than the magnetic resistances E and F of the side chips 13 and 14, since the magnetic flux D is larger than the magnetic flux passing through the core 14. As a result, the magnetic flux from the outside, for example, the magnetic flux as the noise from the CRT (cathode ray tube) used as a display of a personal computer or the like, is relatively small in the amount of interlinking with the coils 15 and 16. The S / N ratio of the output signal is improved.

Further, since only the side chips 13 and 14 are fitted in the hollow portions of the coils 15 and 16, respectively, and the protruding portion of the back core 18 is not fitted, the coils 1 and 14 are not fitted.
The inner diameters of 5 and 16 are made relatively small. In this case, the amount of interlinking of the external magnetic flux with the coils 15 and 16 is further reduced, so that the S / N ratio of the output signal of the magnetic head 10 is further improved.

FIG. 4 shows an example of an apparatus for measuring the CRT noise resistance characteristic of the magnetic head. in this case,
The magnetic head is designed to be measured in a state where it is incorporated in a floppy disk drive device. In FIG. 4, the measuring device 20 is a CRT mounted on a measuring table 21.
22, a floppy disk drive device 23 provided with a magnetic head supported at a predetermined height adjacent to the CRT 22, and a measuring device 24 to which an output signal of the magnetic head of the floppy disk drive device 23 is input. It consists of The CRT 22 is a CRT having a general configuration, and the CRT 22 is turned on at the time of measurement by being supplied with a drive voltage from a power source (not shown).

The floppy disk drive device 23 is
It is a general structure housed in a case, and at the time of measurement, the shield cover at the bottom is removed, and it is placed on the flat box 25 so that it is supported at the predetermined height. It has become. In this case, the floppy disk drive device 23 to be measured includes the magnetic head 1 having the conventional E-shaped back core 9 and the magnetic head 1 according to the present invention.
A drive incorporating a magnetic head with a T-shaped back core of some kind is used. The measuring device 24 is a time interval analyzer in this case, and is connected so that the output signal of the magnetic head of the floppy disk drive device 23 is input.

Here, when measuring the CRT resistance, the floppy disk drive device 23 is, as shown in FIG. 5, a measurement direction 1 in which the bottom surface is directed to the CRT 22 and the bottom surface is the CRT 22 as shown in FIG. With respect to side 0 and side 1 of the floppy disk, respectively, with respect to the measuring direction 2, which is directed in the opposite direction, the left side surface is facing the CRT 22, and the right side surface is facing the CRT 22. , Measurement work is performed. The floppy disk drive 23 is a CRT for measurement.
From 0, 3, 5, 8, 10, 12, 15, 20, 25,
It is performed at a distance of 30 cm.

Under these conditions, the measurement directions 1, 2, 3, for each floppy disk drive device
At 4, the measuring device 24 measures the peak shift sigma at each of the above distances as the CRT resistance characteristic. Here, the vertical axis of the graphs of FIGS. 6 to 13 is the peak shift sigma. The peak shift sigma is the deviation of the peak shift of the output signal of the magnetic head, and has a relationship that the peak shift sigma decreases when the CRT noise resistance is good.

From the measurement results, the graphs of FIGS. 6 to 13 are obtained. That is, FIG. 6 is a side 0 in the measurement direction 1, FIG. 7 is a side 1 in the measurement direction 1, FIG. 8 is a side 0 in the measurement direction 2, FIG. 9 is a side 1 in the measurement direction 2, and FIG. 0, FIG. 11 shows the measurement results for side 1 in measurement direction 3, FIG. 12 shows side 0 for measurement direction 4, and FIG. 13 shows measurement results for side 1 in measurement direction 4. Thus, in any case, the magnetic head 10 provided with the T-shaped back core 18 according to the present invention has a higher peak than the magnetic head 1 provided with the conventional E-shaped back core (E-type BC) 9. It is clear that the shift sigma is small and the CRT resistance is good.

Although the magnetic head for a floppy disk has been described in the above embodiments, the present invention is not limited to this, and it is obvious that the present invention can be applied to a magnetic head for another magnetic recording medium.

[0027]

As described above, according to the present invention, it is possible to provide a magnetic head in which the coil is made compact and the SN ratio is improved.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an embodiment of a magnetic head according to the present invention.

FIG. 2 is an exploded perspective view of the magnetic head of FIG.

3 is a schematic cross-sectional view showing a main part of the magnetic head of FIG.

FIG. 4 is a schematic view showing an apparatus for measuring a CRT resistance characteristic of a magnetic head.

5 is an explanatory view showing a measuring direction of a floppy disk drive device by the device of FIG.

FIG. 6 is a graph showing CRT resistance characteristics on the side 0 side in the measurement direction 1 of the magnetic head according to the present invention and the conventional magnetic head.

FIG. 7 is a graph showing CRT resistance characteristics on the side 1 side in the measurement direction 1 of the magnetic head according to the present invention and the conventional magnetic head.

FIG. 8 is a graph showing CRT resistance characteristics on the side 0 side in the measurement direction 2 of the magnetic head according to the present invention and the conventional magnetic head.

FIG. 9 is a graph showing CRT resistance characteristics on the side 1 side in the measurement direction 2 of the magnetic head according to the present invention and the conventional magnetic head.

FIG. 10 is a graph showing CRT resistance characteristics on the side 0 side in the measurement direction 3 of the magnetic head according to the present invention and the conventional magnetic head.

FIG. 11 is a graph showing CRT resistance characteristics on the side 1 side in the measurement direction 3 of the magnetic head according to the present invention and the conventional magnetic head.

FIG. 12 is a graph showing CRT resistance characteristics on the side 0 side in the measurement direction 4 of the magnetic head according to the present invention and the conventional magnetic head.

FIG. 13 is a graph showing CRT resistance characteristics on the side 1 side in the measurement direction 4 of the magnetic head according to the present invention and the conventional magnetic head.

FIG. 14 is a schematic perspective view showing an example of a conventional magnetic head.

15 is an exploded perspective view of the magnetic head of FIG.

16 is a schematic cross-sectional view showing the main parts of the magnetic head of FIG.

[Explanation of symbols]

 10 magnetic head 11 head core 12 center core 13 and 14 side chip 15 recording / reproducing coil 16 erasing coil 17 bobbin 18 back core 18a central protrusion 20 measuring device 21 measuring table 22 CRT 23 floppy disk drive device 24 measuring instrument

Claims (3)

[Claims] 1. A center core, and a first side chip as a magnetic core half body for a recording / reproducing head and a second side as a magnetic core half body for an erasing head, which are integrally attached to both side surfaces of one end of the center core. A chip, a recording / reproducing coil and an erasing coil provided around the first and second side chips, and a back core attached to the other end side of the center core, the first side chip and the second side chip And the back core is formed in a T shape including a first portion extending in one direction and a second portion extending substantially vertically from the vicinity of the middle of the first portion. And a magnetic head. 2. The magnetic head according to claim 1, wherein a protrusion that is a second portion of the back core is bonded to a side surface of the center core on the other end side. 3. The recording / reproducing coil and the erasing coil are closely arranged around the first side chip and the second side chip, respectively, so that they are formed small. Item 1. The magnetic head according to Item 1.