JP3440327B2 - Magnetic head - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head used in a device for recording / reproducing or erasing a signal on a magnetic recording medium such as a floppy disk device or a hard disk device.

[0002]

2. Description of the Related Art Conventionally, FDD (Floppy Disc Drive)
Is installed inside a personal computer or the like, but magnetic flux flows into the magnetic head core of the FDD due to the influence of electromagnetic waves from a cathode ray tube, a switching power supply, etc., and this magnetic flux causes noise and causes a read error. . Therefore, against such noise generation, a back yoke (referred to as a shield portion) made of a magnetic material such as ferrite or permalloy is provided on the outer peripheral portion of the magnetic head core to guide a magnetic flux from an external magnetic field to the back yoke, Various magnetic heads having a structure for preventing magnetic flux from flowing to the magnetic head core have been proposed. However, in recent years, the magnetic disk device tends to have higher density and smaller size, and the magnetic head used in the magnetic disk device is also downsized. Since a thin FDD with a half-inch thickness has come to be used in notebook personal computers and the like, it has become difficult to use a back yoke of the present size as a shield for a magnetic head.

Therefore, Japanese Patent Application Laid-Open No. 7-235013 discloses a magnetic head in which a back yoke is integrated. As shown in FIG. 4, the magnetic head 41
Reference numeral 5 denotes a recording / reproducing coil 410 into which the front core 401, the back yoke 402, and the leg portion 405 of the back yoke are inserted.
And an erasing coil 411 into which the leg portion 406 of the back yoke is fitted. The back yoke 402 includes a substantially annular outer peripheral portion 403, a bottom portion 404, and three leg portions 405.
It is composed of 406 and 407. Then, the leg portion 4 inserted into the recording / reproducing coil 410 of the bottom portion 404.
05 and the leg portion 406 inserted into the erasing coil 411 are provided with openings 408 and 409, through which lead wires of the recording / reproducing coil and the erasing coil are drawn to the outside and external connection terminals. Connected to. With the above structure, the magnetic head is shielded by the outer peripheral portion 403 and the bottom portion 404.

However, in the above magnetic head, it is difficult to make the legs thinner in the manufacturing process.
Japanese Patent Publication No. 209204 discloses a method of thinning a leg by post-processing. As shown in FIG. 5, when the back yoke 502 is formed by powder molding and firing, the three leg portions 503, 504, 505 are connected to the substantially annular outer peripheral portion 403, and after firing, after grooving or the like. The legs are separated into a predetermined width by processing. Then, the notches 507, 5 are formed in the outer peripheral portion 506 during the processing.
08 is created, and the lead wires of the recording / reproducing coil and the erasing coil are drawn out from the notch and connected to the external connection terminal.

Further, in Japanese Patent Application No. 9-212102, a winding portion in which the efficiency of external connection work of the lead wire of the magnetic head is improved is housed in a back yoke and the terminal block is arranged outside. A bobbin type with terminals is disclosed. As shown in FIG. 6, the back yoke 601
Two notches 603 and 604 are provided on the outer peripheral portion 602. The recording / reproducing coil 605 and the erasing coil 606 are composed of the winding portions 607 and 608 and the bobbin extending portion 6.
09, 610 and terminal blocks 612, 613, and notches 603, 60 of the back yoke 601.
4 has a structure in which the bobbin extending portions 609 and 610 engage with each other.

[0006]

However, in the magnetic head having a structure in which the above-mentioned back yoke is integrated with the magnetic head and the lead wire is drawn out from the opening at the bottom, a bobbin type coil with a terminal is used to shield the whole. In that case, there is a drawback that the shape of the back yoke becomes large. Also, because the ferrite used for the back yoke is made by firing a powder molded product at high temperature,
If you try to make the legs thin, the legs will bend during firing,
There is a defect that cracks may occur, and it is difficult to create a predetermined leg size.

Further, in the case of the above-mentioned magnetic head in which the leg portions are post-processed to have a predetermined size, it is necessary to use the tweezers to pull out the lead wire of the coil from the notch formed in the outer peripheral portion. However, there is a drawback that not only the number of working steps is increased, but also the lead wire and the external connection terminal are damaged.

Further, in the case of a bobbin type magnetic head with a terminal in which the terminal block is arranged outside the back yoke,
It is difficult to miniaturize the magnetic head because the terminal block is located outside, and the lead wires on the terminal block easily come into contact with the shutter of the disk during assembly work or during use, causing disconnection. was there.

The present invention has been made in view of the above problems, and it is possible to reduce the size of a magnetic head in which a front core and a back yoke are brought into contact with each other to form a closed magnetic circuit, by using a bobbin type coil with a terminal. The present invention aims to provide a structure of a magnetic head.

[0010]

In order to solve the above-mentioned problems, the invention according to claim 1 relates to a magnetic head, wherein a front core body having an operating gap is inserted into a slider having a hole to be integrated into a front core. When the back yoke where the multiple legs projecting from the bottom portion of the shield case formed by the outer body and the substantially flat bottom of a substantially annular core front body to form a bonded closed magnetic path, one end A magnetic head having a connection terminal block and a coil wound around a bobbin inserted into the leg portion of the back yoke, wherein the coil is inserted
And the outer body near the legs of the back yoke and the front
Grinding on the bottom part is similar to the bobbin terminal block.
A notch having a size of a degree is formed, and the bobbin terminal block is housed in the notch .

In order to solve the above problems, the invention according to claim 2 relates to the magnetic head according to claim 1, wherein the front part of the core has a recording / reproducing gap and an erasing gap, and the bottom part of the shield case. A leg into which a recording / reproducing coil is inserted, a leg into which an erasing coil is inserted, and a leg into which neither of the coils is inserted between the two legs, and a leg into which the both coils are inserted Is characterized in that it has two notches in the vicinity of, and the terminal blocks of the recording / reproducing coil and the erasing coil are housed in the respective notches.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a magnetic head according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an exploded perspective view showing the structure of an embodiment of a magnetic head according to the present invention. As shown in FIG. 1, the magnetic head includes a front core 1, recording / reproducing / erasing coils 13 and 14, and a back yoke 4. The front core 1 has a core front body 3 made of Mn—Zn ferrite or the like having an operation gap (recording / reproducing gap and erasing gap), and a hole portion having the core front body 3 in the hole portion. And a slider 2 made of non-magnetic ceramics such as calcium titanate. The recording / reproducing coil 13 is integrally formed with a winding portion 13c around which a coil wire is wound. It is composed of a bobbin collar 13d and a terminal block 13b. Similarly, the erasing coil 14 is composed of a winding portion 14c around which a coil wire is wound, a bobbin collar 14d and a terminal block 14b which are integrally formed. The back yoke 4 includes a shield case formed by a substantially annular outer body 20 and a bottom portion 30 on a substantially flat surface, and three leg portions 3 extending from the bottom portion 30.
2, 33, 34, and notches 8a, 8b are formed in the outer body and the bottom portion of the leg portions 32, 33 which are close to each other.

FIG. 2 is a perspective view of a magnetic head in which the recording / reproducing / erasing coil is inserted in the leg portion. Leg 3
The terminal block 13b of the recording / reproducing coil 13 inserted in 2 is
The bobbin coil with terminals has a structure in which the back yoke 4 is housed in a notch 8a which is formed by cutting out the side portion and the bottom surface of the back yoke 4 without being arranged outside the back yoke 4. Can be used. Similarly, the erasing coil 1 inserted in the leg portion 33
The fourth terminal block 14b is also housed in the notch 8b having the same shape as the notch 8a. The front core 1 has a recording / reproducing coil 13 in the notches 8a and 8b.
And the core front body 3 and the leg portions 32, 33, 3 of the back yoke 4 on the upper portion of the back yoke 4 in which the erasing coil 14 is housed.
4 is arranged so as to be joined to form a closed magnetic circuit. Therefore, the upper part of the coil is covered with the slider 2 formed of the non-magnetic ceramics, and thus has a shield effect against external noise. Here, three legs extending from the bottom are formed and two coils of the recording / reproducing coil and the erasing coil are inserted, but the number of legs used may be arbitrary and the size of the notch The size and shape may be arbitrarily formed according to the usage form.

FIG. 3 shows the notch 8a of the back yoke 4,
It is a perspective view showing the creation state of 8b portion. It is a cutout portion in which the portion shown by the dotted line in the figure is formed, and the leg portions 32, 33
As shown by the connected dotted line, before the cutout of the back yoke is created, extends in the direction in which the legs 32, 33, 34 are arranged and is connected to the outer body 20, and the cutout 8
It can be ground by machining etc. at the time of making a and 8b, and is adjusted to a predetermined leg size to be inserted into the recording / reproducing coil or the erasing coil. In addition, the leg portion 34 in which the coil is not inserted
For, there is no need to adjust the dimensions of the legs accurately,
There is no need to post-process the legs as they are during powder molding and firing. When the recording / reproducing coil 13 and the erasing coil 14 are inserted into the legs 32 and 33, respectively, the terminal block 13
The outer contour portions of b and 14b have the same shape as the contour portion of the shield case in which the notches 8a and 8b are formed. Therefore, the recording / reproducing / erasing coil can be attached without increasing the shape of the back yoke.

[0016]

In the invention according to claim 1 or 2, the notch is formed in the vicinity of the leg portion into which the coil of the shield case is inserted, and the bobbin terminal block is housed in the notch, whereby the back yoke The outer shape can be reduced.
In addition, above the cutout portion in which the terminal block is stored,
Since the front core is arranged, it is possible to obtain a shielding effect against noise from above the outside.

Further, since the leg portion inserted into the recording / reproducing coil or the erasing coil can be ground by machining at the time of making the notch and can be adjusted to a desired dimension, the back yoke is powder-molded and fired. In the step of forming, the leg can be formed thick so that it is not deformed or cracked.

[0018]

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a configuration of an embodiment of a magnetic head of the present invention.

FIG. 2 is a perspective view showing the configuration of an embodiment of a magnetic head of the present invention.

FIG. 3 is a perspective view showing one form of a notch forming portion of the back yoke according to the magnetic head of the present invention.

FIG. 4 is an exploded perspective view showing a configuration of a conventional magnetic head.

FIG. 5 is an exploded perspective view showing a configuration of a conventional magnetic head different from that of FIG.

FIG. 6 is an exploded perspective view showing a configuration of a conventional magnetic head different from those in FIGS. 4 and 5.

[Explanation of symbols]

1 front core 2 slider 3 core front body 4 back yoke 8a, 8b Notch 13 recording / reproducing coil 13b terminal block 13c winding part 13d Bobbin Tsuba 14 Erase coil 14b terminal block 14c winding part 14d Bobbin Tsuba 20 Outer body 30 bottom 32, 33, 34 legs

Continuation of the front page (56) Reference JP-A-10-40526 (JP, A) JP-A-7-254107 (JP, A) JP-A-7-153048 (JP, A) JP-A-7-235013 (JP , A) Japanese Unexamined Patent Publication No. 7-262517 (JP, A) Actual development No. 7-10802 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G11B 5/10-5/17 G11B 5/265-5/29

Claims (2)

(57) [Claims] 1. A front case in which a core front body having an operating gap is inserted and integrated into a slider having a hole portion, and a bottom portion of a shield case formed by a substantially annular outer body and a substantially flat bottom portion. and the back yoke that the multiple leg core front body to form a bonded closed magnetic path for projecting, coils wound on a bobbin which is inserted into the leg portion of the back yoke has a connection terminal block one end portion A magnetic head having: and a vicinity of a leg portion of the back yoke into which the coil is inserted
The outer body and the bottom of the
Magnetic head is characterized in that down terminal block and comparable size cutout of forms, for accommodating the terminal block of the bobbin該切Ri within notch. 2. A front portion of the core has a recording / reproducing gap and an erasing gap, and a leg portion into which the recording / reproducing coil is inserted, a leg portion into which the erasing coil is inserted, and the two leg portions are provided on a bottom portion of the shield case. And a leg portion into which the coils are not inserted, and two notches near the leg portions into which the coils are inserted, and each notch has a terminal block for a recording / reproducing coil and an erasing coil. The magnetic head according to claim 1, wherein the magnetic head is stored.