JP2002133607A - Magnetic head and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To equalize gap depths of a read core and dummy cores and to enable the number of parts to be reduced, in a read and write combination type magnetic head having such a magnetic core that two dummy cores joined to the both sides of a read core for reading in the track width direction through the non-magnetic spacing members and a write core for writing with a larger track width than the read core are joined through a magnetic head gap. SOLUTION: Before joining two dummy cores 2 to the both sides of the read core 1 in the track width direction, on the sides of the dummy core 2 joining to the read core 1, the non-magnetic spacing members 13 are formed by coating with the non-magnetic coating material. Alternatively, a non-magnetic spacing member with coating of the non-magnetic coating material may be formed on the both sides of the read track core 2 in the track width direction.

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 writing (recording) or reading (reproducing) magnetically recorded information by bringing a magnetic core wound with a coil into sliding contact with a magnetic recording medium and manufacturing the same. It is about the method.

[0002]

2. Description of the Related Art Conventionally, the above-mentioned magnetic head includes a write-only magnetic head for writing magnetic recording information and a read-only magnetic head for reading magnetic recording information, as well as a read / write head used for writing and reading. There is a magnetic head called a write combination type. A conventional structure of the read / write combination type magnetic head will be described with reference to FIGS.

The magnetic head shown in FIG. 7 has a magnetic core for writing and reading magnetically recorded information on a magnetic recording medium (not shown) sliding in the direction of arrow F via a magnetic gap G. The magnetic core includes a write core 3 for writing having a track width of H1, a read core 1 for reading having a smaller track width H2, and two dummy cores 2. Read core 1 and write core 3 are approximately C
The dummy core 2 is formed in a straight shape. (See FIGS. 4 and 8) Dummy core 2
Constitutes a write magnetic circuit having a track width H1 by compensating for the difference between the track widths H1 and H2. The write magnetic circuit is involved in writing but is not involved in reading, and is provided on both sides of the read core 1 in the track width direction. It is joined via a spacing plate 4 made of a non-magnetic material and having a predetermined thickness. Spacing plate 4
Is a non-magnetic spacing member for maintaining a necessary spacing between the lead core 1 and the dummy core 2. And lead core 1
The light core 3 is joined with the dummy core 2 and the spacing plate 4 joined together through the magnetic gap G,
Are joined.

At the time of writing magnetic recording information, writing is performed with a track width H1 by a magnetic circuit including a write core 3, a read core 1, and two dummy cores 2, and at the time of reading, a track width H2 is determined by a magnetic circuit including a read core 1 and a write core 3. Is read.

[0005] As shown in FIG. 8, a write coil 5 for writing, that is, a bobbin 7 wound with a coil for generating a magnetic field for writing magnetic recording information is mounted on the write core 3. A read coil 6 for reading, that is, a bobbin 8 wound with a coil for converting a change in a magnetic field in the read core 1 according to magnetic recording information of a magnetic recording medium into an electric signal is mounted on the read core 1. You.

[0006] The head element composed of the cores 1, 2, 3, spacing plate 4, coils 5, 6 and bobbins 7, 8 is shown in FIG.
And is positioned and fixed at a predetermined position using a positioning support (also referred to as a clamper) (not shown). The terminals of the write coil 5 and the read coil 6 are connected to a connection terminal 10 so that the magnetic head can be easily connected to an electric circuit of a magnetic recording / reproducing apparatus main body incorporating the magnetic head. The inside of the shield case 9 is filled with an embedding resin 11 to fix and protect the internal components. Each core 1,
The distal ends of the shield case 9 are exposed to the outside through an opening 9 a formed in the upper surface of the shield case 9 in FIG. 7, and the distal end surface is in sliding contact with the upper surface of the shield case 9 with a magnetic recording medium (not shown). The sliding surface of the magnetic recording medium is constituted. The sliding surface is formed as a uniform curved surface gently curved along the magnetic recording medium sliding direction F in order to perform writing and reading well. The processing of the sliding surface is performed by grinding at the end of the manufacturing process of the magnetic head.

[0007]

In the process of assembling the magnetic core in the above-described conventional magnetic head manufacturing process, first, as shown in FIG. 4, two pieces of lead core 1 are provided on both sides in the track width direction (thickness direction). The spacing plate 4 and two dummy cores 2 disposed on both outer sides thereof are superposed and bonded together to form a unit of the lead core 1 and the dummy core 2 (hereinafter referred to as a lead / dummy core unit). Thereafter, the read / dummy core unit and the write core 3 are butted and bonded via a magnetic gap G. Although not shown in FIG. 4, the bobbin 8 is attached to the lead core 1 in a single state and the lead coil 6 is wound before the lead / dummy core unit is manufactured. The bobbin 7 is attached to the write core 3 and wound around the write coil 5 before joining with the read / dummy core unit.

However, in the process of manufacturing the lead / dummy core unit, as many as five parts must be joined at the same time, so that the parts become irregular after joining, which causes a magnetic head to be finally manufactured. The gap depth between the core read core 1 and the two dummy cores 2 is irregular, which often causes the function as a magnetic head to not be satisfied. The irregular situation will be described with reference to FIGS.

FIG. 5 is a perspective view showing an irregular state when the above-mentioned five parts are joined. Here, in the lead / dummy core unit 12, a lead core 1, two dummy cores 2, and two spacing plates 4 are shown. The positions in the gap depth direction indicated by arrows are irregular. 5 and 6, the illustration of the bobbin 8 and the lead coil 6 is omitted as in FIG.

FIG. 6 is a plan view of a joint surface of the read / dummy core unit 12 to be joined to the write core 3, showing a situation where the gap depth is irregular due to the irregularity at the time of joining. In the processing of the sliding surface of the magnetic recording medium performed at the end of the manufacturing process of the magnetic head, the read / dummy core unit 12 as a part of the magnetic core is moved in the gap depth direction of the magnetic core as shown in FIG. The leading end surface is ground to the J surface as a part of the sliding surface of the magnetic recording medium so that the dimension of the left and right directions in FIG.
The gap depth between the read core 1 and the two dummy cores (dimension B,
C, D) are determined. If the gap depth is irregular in each of the read core 1 and the two dummy cores 2 as shown in FIG. 6, a serious functional failure is likely to occur.

In the example shown here, with respect to the gap depth, the lead core 1 has a dimension B. Even if this is set to the central dimension, the lower dummy core 2 in the figure becomes the dimension D, which is much larger than the dimension B. , And the size of the upper dummy core 2 in FIG. This is only an example, but in this way, in the conventional magnetic head,
Due to the large number of components at the time of joining the read / dummy core unit, irregularities are generated, which causes irregularities in the gap depth. As a result, a case where the function as a magnetic head cannot be performed may occur. There is also a problem that the cost is increased due to the large number of parts.

It is an object of the present invention to provide a read / write combination type magnetic head of the type described above, in which the gap depth between the above-mentioned read core and two dummy cores can be made uniform and the number of parts can be reduced. It is to provide a manufacturing method.

[0013]

According to the present invention, two dummy cores are joined to both sides of a read-out read core in a track width direction via a non-magnetic spacing member. In a magnetic head having a magnetic core formed by joining a write core having a track width larger than that of the read core via a magnetic gap, the nonmagnetic spacing member may be made of a nonmagnetic coating material (for example, acrylic resin or epoxy resin). (Based resin, etc.).

In the method of manufacturing a magnetic head, before joining two dummy cores to both sides of the read core in the track width direction, a non-magnetic coating may be formed on a side surface of the two dummy cores joined to the read core. Forming the non-magnetic spacing member by coating a material, or forming the non-magnetic spacing member by coating a non-magnetic coating material on both side surfaces in the track width direction of the lead core. Adopted.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. The magnetic head of the present embodiment
This is a read / write combination type magnetic head as described above, and the structure thereof will be described only for points different from the conventional example described with reference to FIGS.

First, the structure of the magnetic head of this embodiment will be described. FIG. 1 shows the structure of a read core 1 and two dummy cores 2 of the magnetic head of the present embodiment. As shown here, the present embodiment is different from the conventional example in that the non-magnetic spacing member 13 having a predetermined thickness is provided on the side surface of each of the two dummy cores 2 joined to each of the lead cores 1.
Is formed by coating with a non-magnetic coating material. The non-magnetic spacing member 13 is for maintaining a necessary spacing between the lead core 1 and the dummy core 2 depending on its thickness, similarly to the spacing plate 4 of the conventional example.

The material used as the coating material for forming the nonmagnetic spacing member 13 is, for example, an acrylic resin or an epoxy resin. By adding carbon powder, silica powder, ceramic powder, or the like to the coating material, the thickness of the nonmagnetic spacing member 13 can be stabilized. The powder used at that time, such as carbon powder, silica powder or ceramic powder,
Granular (spherical) or needle-shaped non-magnetic spacing members 13 are used depending on the specifications such as the thickness, thickness accuracy, wear resistance, and environmental performance. Also, as a powder to be added to the coating material, by using a non-magnetic metal powder of high conductivity, such as copper, aluminum, titanium and their alloys,
Magnetic flux leaking from the dummy core 2 to the lead core 1 can be suppressed.

The structure of the magnetic head of this embodiment other than the dummy core 2 in which the nonmagnetic spacing member 13 is formed on the side surface is the same as that of the conventional example, and the structure of the magnetic head of this embodiment and its magnetic core is shown in FIG. In the structure of the conventional example shown in FIGS. 7 and 8, two non-magnetic spacing plates 4 are replaced by the above-described non-magnetic spacing members 13 made of two coating materials.

Next, the manufacturing process of the magnetic head of this embodiment will be described.

First, in the assembling process of the magnetic core, before joining the two dummy cores 2 to both sides of the read core 1 in the track width direction, as shown in FIG. The non-magnetic spacing member 1 is coated with the above-described non-magnetic coating material.
Form 3 Specific methods of coating at that time include, for example, spray coating, printing, roller coating, dip coating, and the like.

Next, the sides of the two dummy cores 2 on which the non-magnetic spacing members 13 are formed are overlapped and bonded to the side surfaces on both sides of the lead core 1 in the track width direction, and the lead / dummy core unit 12 shown in FIG. Get. Before the joining, although not shown in FIGS. 1 and 2, the same bobbin 8 as the conventional example shown in FIG. 8 is mounted on the lead core 1, and the lead coil 6 is wound thereon.

The subsequent steps are the same as in the conventional example. That is, the write core 3 on which the bobbin 7 is mounted and the write coil 5 is wound in advance and the read / dummy core unit 12 of FIG.
Obtain a magnetic core. Then, the magnetic core is fitted into the shield case 9 of FIG.
The magnetic core is positioned at a predetermined position by a support (not shown) and fixed as desired in the opening 9a formed on the upper surface in FIG. And cure. Finally, the tip surface of the magnetic core and the upper surface of the shield case 9 are ground to form a uniform curved surface as a magnetic recording medium sliding surface, thereby completing a magnetic head.

According to the present embodiment as described above, in the process of manufacturing the lead / dummy core unit 12, two dummy cores 2 each integrally formed with a non-magnetic spacing member 13 are joined to both sides of the lead core 1. Since substantially only three components are joined, and the respective components are easily aligned, the components can be joined with their positions in the gap depth direction being accurately adjusted as shown in FIG. In the manufacturing process of the magnetic head, the leading end of the read / dummy core unit 12, which is a part of the magnetic core, is finally processed from the rear end by J of dimension A as shown in FIG. The surfaces are ground to determine the gap depths B, C, and D of the lead core 1 and the two dummy cores 2, but they can be made uniform.

Further, the manufacturing process of the lead / dummy core unit 12 is simplified, and the number of parts is substantially two.
Since the number of points is reduced, cost can be reduced.

By the way, as another embodiment, the non-magnetic spacing member 13 is not formed on the side surface of the dummy core 2 and the non-magnetic coating material is coated on both side surfaces of the lead core 1 in the track width direction. A spacing member may be formed. It is needless to say that the formation is performed before the lead core 1 and the two dummy cores 2 are joined. Even in this case, a similar effect can be obtained.

[0026]

As is apparent from the above description, according to the present invention, in the read / write combination type magnetic head, the non-magnetic spacing member between the read core of the magnetic core and the two dummy cores on both sides thereof is provided. Is formed by coating a non-magnetic coating material, so that the gap depth between the read core and the two dummy cores can be made uniform, the quality of the magnetic head can be improved, and the read core and the two dummy cores can be further improved. And the number of parts can be reduced, so that an excellent effect of reducing costs can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a lead core of a magnetic head according to an embodiment of the present invention and two dummy cores each having a non-magnetic spacing member formed on a side surface by coating before joining.

FIG. 2 is a perspective view of a lead / dummy core unit formed by joining the lead core and two dummy cores.

FIG. 3 is a plan view of a joint surface with a write core showing a state in which a gap depth of each core of the read / dummy core unit is made uniform.

FIG. 4 is a perspective view of a conventional magnetic head before a read core, two spacing plates, and two dummy cores are joined.

FIG. 5 is a perspective view showing an irregular state of each member of a lead / dummy core unit formed by joining the lead core, two spacing plates, and two dummy cores.

FIG. 6 is a plan view of a joint surface with a write core showing a state in which gap depths of respective cores of the read / dummy core unit are uneven.

FIG. 7 is a perspective view showing the overall appearance of a conventional magnetic head.

FIG. 8 is a perspective view of a head element including a magnetic core, a bobbin, and a coil of the magnetic head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lead core 2 Dummy core 3 Write core 5 Write coil 6 Lead coil 7, 8 Bobbin 9 Shield case 10 Connection terminal 11 Resin for embedding 12 Lead / dummy core unit 13 Nonmagnetic spacing member made of coating material

Claims (10)

[Claims] 1. A read core having two dummy cores joined to each other in a track width direction of a read core via a non-magnetic spacing member, and a write core having a larger track width than the read core via a magnetic gap. A magnetic head having a magnetic core joined by bonding, wherein the non-magnetic spacing member is formed by coating with a non-magnetic coating material. 2. The magnetic head according to claim 1, wherein an acrylic resin is used as the coating material. 3. The magnetic head according to claim 1, wherein an epoxy resin is used as the coating material. 4. The magnetic head according to claim 1, wherein a carbon powder is added to the coating material. 5. The coating material according to claim 1, wherein a silica powder is added to the coating material.
The magnetic head according to the paragraph. 6. The magnetic head according to claim 1, wherein a ceramic powder is added to the coating material. 7. The magnetic head according to claim 1, wherein a non-magnetic high-conductivity metal powder is added to the coating material. 8. A read core having two dummy cores joined to each other in a track width direction of a read core via a non-magnetic spacing member, and a write core having a larger track width than the read core via a magnetic gap. In a method of manufacturing a magnetic head having a magnetic core formed by joining together, before joining the two dummy cores on both sides in the track width direction of the read core, on a side surface of the two dummy cores joined to the read core, A method for manufacturing a magnetic head, comprising a step of forming the non-magnetic spacing member by coating with a non-magnetic coating material. 9. A structure in which two dummy cores are joined to both sides of a read read core in a track width direction via a non-magnetic spacing member, and a write write core having a larger track width than the read core is connected via a magnetic gap. In the method for manufacturing a magnetic head having a magnetic core formed by joining together, before joining the two dummy cores to both sides in the track width direction of the read core, non-magnetic Forming the non-magnetic spacing member by coating with a coating material according to (1). 10. The method of manufacturing a magnetic head according to claim 8, wherein any one of spray coating, printing, roller coating, and dip coating is used as the coating method.