JP3277269B2 - Magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetic head used for a floppy disk drive (FDD) and the like.

[0002]

2. Description of the Related Art In magnetic recording, a magnetic flux leaking from a magnetic recording medium is taken into a magnetic head including a coil from an operation gap to perform a reproducing process. However, a magnetic flux flows into the magnetic head core due to an external magnetic field from a motor, a power supply, or the like in the magnetic head, and this magnetic flux may cause noise.

To prevent such noise, a shield ring (shield portion) made of a magnetic material such as ferrite or permalloy is provided on the outer peripheral portion of the magnetic head core, and a magnetic flux from an external magnetic field is guided to the shield ring. There have been proposed various magnetic heads having a structure in which the magnetic head is prevented from flowing into a magnetic head core.

Since this shield ring is made of a magnetic material like the magnetic head core, it is conceivable that both are integrated. As an example of a magnetic head of a type in which such a shield ring is integrated with a magnetic head core, there is one shown in FIG. 10 (see JP-A-7-235013).

In FIG. 1, a magnetic head 1 includes a front core 2 whose one surface slides on a magnetic recording medium (not shown),
Mn-Z bonded to the other surface of the front core 2 with an adhesive such as an epoxy resin or an ultraviolet curable resin (UV resin).
The back yoke 3 is made up of a magnetic material such as an n ferrite material or a Ni-Zn ferrite material, and a recording / reproducing coil 4 and an erasing coil 5 mounted on the back yoke 3.

The front core 2 has a recording / reproducing gap 6.
And a first and second outriggers 9 and 10 bonded to both surfaces of the composite core 8 with an epoxy resin or the like. And is substantially rectangular. Composite core 8
Is roughly composed of a first core body 11 having a recording / reproducing gap 6 on one surface side, and a second core body 12 having an erasing gap 7 joined to the first core body 11. .

The first core body 11 is made of a magnetic material and extends to the other surface of the front core 2. The first core body 11 is joined to the first center core 13 via the recording / reproducing gap 6. And a front side recording / reproducing side core 14 made of a magnetic material extending to the other surface side.

The second core body 12 extends to the other surface of the front core 2 and is joined to the first center core 13. The second center core 15 is made of a magnetic material.
And a front-side erasing side core 16 made of a magnetic material and extending to the other surface of the front core 2 joined to the second center core 15 through the second center core 15. The information signal track recorded by the gap 6 is tunnel erased. The second core body 12 is the first core body 1
The height is set to be equal to the height of 1. In the figure, 1
Reference numeral 7 denotes glass for magnetic insulation.

The first outrigger 9 has a plate shape having the same length as the composite core 8, and has a groove 18 extending in the longitudinal direction on one surface side. The second outrigger 10 has a rectangular parallelepiped shape having the same length dimension as the composite core 8.

The back yoke 3 includes first, second, and third legs 19, 20, and 21 and recording / reproducing and erasing coils 4.
5, a substantially rectangular annular closing body (shielding part) 22 for blocking the influence of an external magnetic field, and a base end of the first, second and third legs 19, 20, 21 and a base of the closing body 22. It is roughly constituted by a substantially rectangular substrate 23 connected to the end side. In this case, the first, second and third legs 19, 20, 2
The back core 24 is composed of the substrate 1 and the substrate 23.

[0011] Only opposite sides 23a and 23b in the width direction of the substrate 23 (referred to as first and second sides) are connected to the closing body 22 (hereinafter, first and second sides of the closing body 22). Are connected to the side portions 23a and 23b of the first and second side walls 22a and 22b.). In addition, the third and fourth sides 23c and 23d orthogonal to the first and second sides 23a and 23b and the side wall of the closing body 22 (hereinafter, referred to as third and fourth side walls). 22c, 22d
The gaps 25, 25 are formed between them, and the lead wire 4a of the recording / reproducing coil 4 and the lead wire 5a of the erasing coil 5 are drawn out.
Further, the upper surface of the first side wall 22 a is joined to the first outrigger 9.

The first and second legs 19 and 20 are formed along the third and fourth sides 23c and 23d and face each other. In addition, the third leg portion 21 includes the first and second legs.
Are formed between the leg portions 19 and 20 of the main body. Recording and reproducing coils 4 and 5 are fitted to the first and second legs 19 and 20, respectively. First and second legs 19, 20
Are respectively joined to the front-side recording / reproducing and erasing side cores 14 and 16, respectively, and
Are joined to the first center core 13 and the second center core 15, and the first side wall 22a is joined to the first outrigger 9. The epoxy resin or the UV resin (ultraviolet curable resin) ), The front core 2 and the back yoke 3 are integrated, and the composite core 8 and the back core 24 are joined and integrated.

As described above, by integrating the composite core 8 and the back core 24, the first center core 13, the third leg 21, the substrate 23, the first leg 19, and the front side recording / reproducing. A recording / reproducing magnetic circuit (symbols omitted) is formed from the recording / reproducing side core 14 and the recording / reproducing gap 6. Similarly, an erasing magnetic circuit (symbol omitted) is formed from the second center core 15, the third leg 21, the substrate 23, the second leg 20, the front-side erasing side core 16, and the erasing gap 7. Have been. The third leg 21 forms a common magnetic path for the recording / reproducing magnetic circuit and the erasing magnetic circuit. Gap 25 of back yoke 3
Are the lead wires 4a of the recording and reproducing and erasing coils 4 and 5,
5a is inserted and pulled out.

In the magnetic head 1 configured as described above, since the closing body (shield part) 22 is provided integrally with the back yoke 3 joined to the front core 2, the shield part is backed. The manufacturing process can be simplified and the cost can be reduced as compared with a magnetic head of a type separately attached to the core.

[0015]

In the magnetic head 1 of FIG. 10 described above, the back core 24 and the closing member (shield) 22 are made of the same magnetic material.
As shown in FIG. 11, some of the magnetic fluxes φ _{1 to} φ ₆ from the external magnetic field flowing into the substrate 23 of the back yoke 3 (for example, FIG.
In this case, the magnetic fluxes φ _{3 to} φ ₅ are generated by the outer peripheral portions (first, second, third, and fourth side wall portions 22a, 22b, 22c, 22) of the closing body 22.
d), the legs (first, second,
The third leg portions 19, 20, 21) led to the composite core 8, and the shielding effect was sometimes reduced. FIG. 11 is a cross-sectional view schematically showing the influence of an external magnetic field of the magnetic head. For convenience, only members made of a magnetic material are indicated by hatching.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a magnetic head which can be mounted so as to integrate a shield portion and which can secure good shielding properties.

[0017]

According to the first aspect of the present invention,
A substantially plate-shaped core front body having an operating gap, a slider constituting a front core whose one surface slides on a magnetic recording medium by integration with the core front body, and joined to the other surface of the front core The back yoke is formed of a back core forming a magnetic circuit corresponding to the operating gap together with the core front body, and a shield portion made of a magnetic material integrated with the back core. The back core has a distal end joined to the core front body to form a part of a magnetic path of the magnetic circuit, and a leg in which a coil is fitted, and the leg is vertically provided. The shield portion is vertically attached to the substrate along the peripheral edge of the substrate, comprising a plate-shaped substrate connected to the base end side of the leg portion.
A slit has a substantially annular side wall surrounding the coil, and a slit is formed near the leg of the substrate and extends in parallel with the core front body joined to the leg.

According to a second aspect of the present invention, in the configuration of the first aspect, the lead wire of the coil is drawn out of the slit.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetic head 1 according to a first embodiment of the present invention will be described below with reference to FIGS.
In addition, the members shown in FIGS.
Description and illustration of the parts will be appropriately omitted.

The magnetic head 1 according to the first embodiment has
As shown in FIGS. 1 and 2, the magnetic head 1 shown in FIG. 10 is different from the magnetic head 1 in that a front core 2A is provided in place of the front core 2 and a back yoke 3A is provided in place of the back yoke 3. . The front core 2A has a substantially rectangular shape, a core body (slider) 30 having one surface sliding on a magnetic recording medium and having a groove 18 on the one surface, and a groove 18.
Hole formed in the core body 30 along the line
And the composite core 8 integrated with the core body 30 to be integrated with the core body 30. Since one surface side of the front core 2A faces the magnetic recording medium, the edge portion (reference numeral is omitted) is chamfered. Also, front core 2A
The other surface is flat-polished after the core body 30 and the composite core 8 are integrated. Furthermore, front core 2A
As shown in FIGS. 2 and 3, the shape of the front core 2A is substantially equal to that of the back yoke 3A (the front core 2A is slightly smaller). The first, second, third, and fourth side walls 22a, 22b, 22c, and 22d of the closing body 22 of FIG.

The back yoke 3A includes, together with the composite core 8, a back core 24 forming a recording / reproducing magnetic circuit and an erasing magnetic circuit (magnetic circuit) corresponding to the recording / reproducing gap 6 and the erasing gap 7 (operating gap). And a closing member (shield portion) 22 made of a magnetic material and integrated with the back core 24.

As shown in FIG. 10, the back core 24 is joined at its front end to the front-side recording / reproducing side core 14 and the front-side erasing side core 16 of the composite core (core front body) 8, and has a magnetic circuit for recording / reproducing. First and second legs 1 which form a part of a magnetic path of an erasing magnetic circuit (magnetic circuit) and into which recording and reproducing coils 4 and 5 are respectively fitted.
9 and 20 and a third leg 21 provided between the first and second legs 19 and 20 and having a distal end joined to the first and second center cores 13 and 15 of the composite core 8. , The first, second and third legs 19, 20 and 21 are suspended from the base end of the first, second and third legs 19, 20 and 21. And a substrate 23.

The closing body 22 is suspended from the substrate 23 along the peripheral portion of the substrate 23, and has first and second legs 19, 20.
Recording and reproducing coils 4, 5 fitted respectively to the
, Second, third, and fourth side wall portions (substantially annular side wall portions) 22 provided to form a substantially rectangular ring so as to surround
a, 22b, 22c and 22d. The distal end surface of the closing body 22 and the first, second, and third legs 19, 2
The tip surfaces of 0 and 21 are polished to have the same height level.

Opposite sides 23a and 23b in the width direction of the substrate 23 (first and second sides) are connected to the first and second side walls 22a and 22b of the closing body 22, respectively. At the same time, third and fourth sides 23c and 23d orthogonal to the first and second sides 23a and 23b are third and fourth sides, respectively.
It is connected to the fourth side wall portions 22c and 22d (FIG. 4),
The gaps 25, 25 provided by the back yoke 3A in FIG.
Is missing.

As shown in FIGS. 5 and 4, the first, second, and third legs 19 are provided on both sides of the first, second, and third legs 19, 20, and 21 on the substrate 23. , 20, 21 (and thus the first, second and third legs 19, 20,
Slits 31, 31 extending in parallel with the composite core 8) joined to 21 are formed, and the third and fourth side walls 22 c, 22 d are connected to the slits 31, 31 to form the deep grooves 32, 32. Are formed.

By forming the slits 31, 31, the substrate 23 is provided with the first, second, and third legs 19, 2.
0, 21; that is, a core side portion (hereinafter, referred to as a substrate core portion) 23a which forms a magnetic path of a recording / reproducing magnetic circuit and an erasing magnetic circuit, and first and second side wall portions 22.
a and 22b separated from the substrate main bodies 23b and 23b. From the slit 31, lead wires 4a and 5a of recording and reproducing and erasing coils 4 and 5 are drawn out. The distal ends of the lead wires 4a and 5a are connected to an external circuit such as an FPC (wiring board, not shown).

The first and second legs 19 and 20 are respectively connected to the front side recording / reproducing and erasing side cores 14 and 16, respectively, and the third leg 21 is connected to the first center core 13 and the second center core 15. And the outer peripheral portion of the front core 2A is connected to the first, second, third, and fourth side walls 22a, 22b, 22c, and 22 of the back yoke 3A.
The front core 2A and the back yoke 3A are integrated with each other and the composite core 8 and the back are bonded together by bonding with an epoxy resin or a UV resin (ultraviolet curing resin). The core 24 is joined and integrated.

Then, as described above, the composite core 8 and the back core 24 are integrated to form the first center core 13, the third leg 21, and the substrate core portion 23 of the substrate 23.
a, the first leg 19, the front-side recording / reproducing side core 14, and the recording / reproducing gap 6 form a recording / reproducing magnetic circuit (reference numeral omitted). Similarly, the second
An erasing magnetic circuit (symbol omitted) is formed from the center core 15, the third leg 21, the substrate core portion 23a of the substrate 23, the second leg 20, the front side erasing side core 16, and the erasing gap 7. I have. The third leg 21
Represents a common magnetic path for the recording / reproducing magnetic circuit and the erasing magnetic circuit.

In the magnetic head 1 configured as described above, the back yoke 3A joined to the front core 2A is integrally provided with the closing body (shield portion) 22, so that the shield portion is backed. The manufacturing process can be simplified and the cost can be reduced as compared with a magnetic head of a type separately attached to the core.

Further, the substrate 23 is formed by forming the slits 31, 31, with a substrate core portion 23 a forming a magnetic path of a recording / reproducing magnetic circuit and an erasing magnetic circuit (magnetic circuit), and first and second side wall portions. Substrate body 2 connected to 22a, 22b
3b, since has become one that is separated into a 23b, when receiving the vertical direction of the external magnetic field phi ₁ to [phi] _6, as shown in FIG. 6, the magnetic flux phi ₁ to [phi] ₃ received in the substrate body 23b, phi ₅ to
About φ ₆ , it leads to the closing body (shield part) 22, and accordingly, the first, second, and third legs 19, 20, and 20.
The magnetic flux (for example, the magnetic flux φ _c received by the substrate core portion 23a) flowing into the composite core 21 and the composite core 8 is reduced (that is,
The shielding effect is improved. ). Therefore, noise due to the external magnetic field is reduced.

When an external magnetic field is applied in a direction perpendicular to the plane of FIG. 6, the magnetic flux flows through the first and second side walls 22a and 22b and the substrate 23, and the composite core 8 and the first, second, and third legs. Part 1
It does not flow to 9, 20, and 21 (that is, the shielding effect is improved). Therefore, noise due to the external magnetic field is reduced.

When an external magnetic field in the left and right direction shown in FIG. 6 is received,
By providing the slits 31, 31, the magnetic flux is
However, the magnetic flux flows through the closing body 22 because the closing body 22 is integrated with the substrate 23. Therefore, the magnetic flux due to the external magnetic field in the left-right direction in FIG.
And almost no flow to the first, second, and third legs 19, 20, and 21 (that is, the shielding effect is improved).
The magnetic flux in the left-right direction in FIG. 6 is orthogonal to the winding direction of the recording / reproducing and erasing coils 4 and 5 (perpendicular to the plane of FIG. 6). The effect will be less. FIG. 6 is a cross-sectional view schematically illustrating the influence of an external magnetic field of the magnetic head. For convenience, only members made of a magnetic material are indicated by hatching. The same applies to FIG. 9 described later.

The slits 31, 31 are parallel to the magnetic circuit (including the back core 24 including the first, second, and third legs 19, 20, 21 as described above), and the like. As shown in FIG. 6, the magnetic flux flowing into the magnetic circuit (including the back core 24 including the first, second, and third legs 19, 20, and 21) decreases.

Since the slits 31 have a simple shape, not only can they be molded with a mold at the same time as forming the back yoke 3A, but a molded product having no slits 31 can be obtained. It can also be obtained by performing machining such as slicing.

FIG. 7 shows a magnetic head 1 according to a second embodiment of the present invention. The magnetic head 1 is different from the magnetic head 1 according to the first embodiment in that a composite core 8 having two operation gaps of a recording / reproducing gap 6 and an erasing gap 7 is provided.
Core 8B having one working gap 40 in place of
Is different. The back yoke 3A has slits 3 as in the magnetic head 1 of the first embodiment.
1, 31 are formed.

In the magnetic head 1 as well, like the magnetic head 1 of the first embodiment, the slits 31 and
With the provision of 31, it is possible to suppress the influence of an external magnetic field and prevent the occurrence of noise.

When the magnitude of the external magnetic field is small, instead of the two slits 31 provided in the magnetic head 1 of the first embodiment, for example, as shown in FIGS. The back yoke 3A may be configured by providing the slit 31 only on one side of the core 24. Again, in this case,
Noise generation can be prevented by suppressing the influence of the external magnetic field.

[0038]

According to the first aspect of the present invention, since the magnetic head is constructed as described above,
Since it is provided integrally with the back yoke joined to the front core, the manufacturing process can be simplified and the cost can be reduced compared to a magnetic head in which the shield is attached separately from the back core. Can be achieved.

Further, since the substrate is separated into a substrate core portion forming a magnetic path of the magnetic circuit and a portion connected to the closing member by forming a slit, the amount of magnetic flux of the external magnetic field guided to the closing member increases. Accordingly, the amount of magnetic flux flowing into the magnetic circuit side is reduced, the shielding effect is improved, and noise due to an external magnetic field is reduced. The slit can be provided in parallel with the magnetic circuit. With this configuration, the magnetic flux flowing into the magnetic circuit is further reduced, and the noise due to the external magnetic field can be further reduced.

According to the second aspect of the present invention, it is not necessary to provide a dedicated lead-out hole for the lead wire of the coil, so that the productivity can be improved accordingly.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing an assembled state of the magnetic head.

FIG. 3 is a plan view showing the same magnetic head.

FIG. 4 is a sectional view showing the magnetic head.

FIG. 5 is a plan view showing a back yoke of the magnetic head.

FIG. 6 is a diagram schematically showing an influence of an external magnetic field of the magnetic head.

FIG. 7 is an exploded perspective view showing a magnetic head according to a second embodiment of the present invention.

FIG. 8 is a perspective view showing a back yoke of a magnetic head according to another embodiment of the present invention.

FIG. 9 is a diagram schematically showing an influence of an external magnetic field of the magnetic head of FIG. 8;

FIG. 10 is an exploded perspective view showing an example of a conventional magnetic head.

11 is a diagram schematically showing the influence of an external magnetic field of the magnetic head of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic head 2A Front core 3A Back yoke 4 Recording / reproducing coil 4 4a Lead wire 5 Erasing coil 5a Lead wire 19, 20, 21 First, second, and third leg portions 22 Closure body 23 Substrate 31 Slit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 5/60 G11B 5/10 G11B 5/127 G11B 5/265

Claims (2)

(57) [Claims] 1. A substantially plate-shaped core front body having an operation gap, and a slider constituting a front core whose one surface slides on a magnetic recording medium by integration with the core front body;
A back yoke joined to the other surface side of the front core, wherein the back yoke forms a magnetic circuit corresponding to the operating gap with the core front body, and is integrated with the back core. The back core has a tip portion joined to the core front body to form a part of a magnetic path of the magnetic circuit, and a leg portion to which a coil is fitted. A flat plate-shaped substrate connected to the base end of the leg portion so as to hang the leg portion, wherein the shield portion is hanged on the substrate along the peripheral edge of the substrate. A magnetic head having a substantially annular side wall surrounding a coil, wherein a slit is formed near the leg of the substrate and extends in parallel with the core front body joined to the leg. . 2. The magnetic head according to claim 1, wherein a lead wire of the coil is drawn out of the slit.