JPH06251308A - Magnetic head - Google Patents

Abstract

PURPOSE:To easily manufacture a magnetic head at a low cost, to eliminate a problem in quality such as generation of bubbles in a surface in slidable contact with a magnetic recording medium and to accurately position a core in the head in which the interval between cores or the interval between the core and a window of a shielded case at a part in slidable contact with the medium is narrow like a magnetic head having a narrow pitch between tracks. CONSTITUTION:A nonmagnetic plate 11 is interposed between cores 1 and between cores 1 of both ends of a part 10 in slidable contact with a magnetic recording medium 9 and a window 6 of a shielded case 4, and the part 10 in the slidable contact with the medium 9 is formed of the core 1, the plate 11 and the case 4. Even if a core holder 3 is molded by casting at a low manufacturing cost such as aluminum die casting, zinc die casting, etc., a die cast product and resin 5 having bubbles do not exist in the part 10 in contact with the medium 9 of the part exposed from the window 6 of the case 4. Thus, there is no fear of damaging the medium 6 or clogging by magnetic powder, and its cost can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head.
More specifically, the present invention relates to a magnetic head in which a core is held by a core holder and accommodated in a shield case, the tip of the core is exposed from a window of the shield case, and is hardened with resin in the shield case, particularly a gap between the core and the core. Alternatively, the present invention relates to improvement of a core holder of a magnetic head in which a gap between a core and a window of a shield case or a gap between the core and a portion of the magnetic recording medium in sliding contact is narrow.

[0002]

2. Description of the Related Art As a magnetic head in which a core is positioned by using a core holder, housed in a shield case, and hardened with a resin, a magnetic head as shown in FIG. 7 is conventionally known. In this magnetic head, a set of core halves 102, 102 respectively held by the core holders 101, 101 are butted and housed in a shield case 103, and a resin 104 is provided around the core holder 101 and the core 102 in the shield case 103.
Is filled in to harden the tip of the core 102 in a state of being exposed from the window 105 of the shield case 103.
Therefore, the resin 104 is exposed in the window 105 of the shield case 103 so as to surround the core 102 as shown in FIG. However, in the case of the magnetic head having this structure, when the magnetic recording medium travels, it contacts the resin 104 exposed around the core 102 to generate frictional heat or static electricity. The coating agent 107 containing the resin adheres to the resin 104 portion to form protrusions that cause spacing loss or the like as shown in FIG. 7B, or the core as shown in FIG. 7C. There is a problem that the entire front end portion of 102 is covered. In the figure, reference numeral 108 is a magnetic shield plate, and 109 is a coil bobbin.

Therefore, it has been conventionally considered to prevent the resin from being exposed in a portion which is in sliding contact with the magnetic recording medium. For example, as shown in FIG.
Core holder 201, which holds the
201f is extended and the window 205 of the shield case 203 is extended.
A portion 20 that is exposed inside and is in sliding contact with the magnetic recording medium 206
Also in 7, the core 202 is considered to be surrounded by the core holder 201. Here, the core holder 201 is
Since it has a complicated shape having a groove for holding the core half 202 and a magnetic shield (not shown) and a recess forming a space for housing a coil bobbin, etc., it is generally formed by die casting. However, in the case of the head structure of FIG. 8, at present, it is formed by cutting a brass material. In this case, the core holder 201 is arranged around the core 202 exposed in the window 205 of the shield case 203, particularly in the portion 207 with which the magnetic recording medium is in sliding contact, and the resin 204 filled in the shield case 203 is not exposed. .

[0004]

However, when the core holder 201 is obtained by cutting a brass material,
There is a problem that the cost becomes high because the processing takes time and the productivity deteriorates. The cost is about 50 times higher than that of die casting, which is a general core holder molding method. Further, when the core holder is manufactured by aluminum die casting, since air bubbles are included in the aluminum die casting parts (about 2% in volume ratio), a concave portion due to the air bubbles is formed on the surface of the polishing surface / the portion 207 with which the magnetic recording medium is in sliding contact. However, the magnetic recording medium may be damaged and magnetic particles may be clogged in the recesses. Further, in the case of die-cast products, there is a problem that it is difficult to obtain accurate positional accuracy of the core because high dimensional accuracy cannot be expected. In addition,
Like a magnetic head with a narrow track pitch, the core 20
2 and the core 202 and the shield case 2 at the interval t ₁ between the core 202 and the portion 207 that is in sliding contact with the magnetic recording medium.
When the distance t _{2 from} the window 205 of 03 is narrow, it is difficult to obtain the comb-teeth-shaped core holder 201 provided with a thin partition wall by cutting because the machining efficiency is low and defective products are likely to occur. is there.

An object of the present invention is to provide a magnetic head which can be easily manufactured at low cost, and which is capable of accurate positioning of the core without quality problems such as generation of bubbles on the surface in sliding contact with the magnetic recording medium. And Particularly, the present invention is low cost and easy even for a magnetic head having a narrow gap between the cores or a gap between the core and the window of the shield case in a portion slidingly contacting the magnetic recording medium, such as a magnetic head having a narrow track pitch. The object is to enable accurate positioning of the core without any quality problem such as generation of bubbles on the surface that is in sliding contact with the magnetic recording medium.

[0006]

In order to achieve the above object, the present invention is to hold a core by a core holder and store the core in a shield case, and to expose the tip of the core through a window of the shield case to form a resin inside the shield case. In the magnetic head solidified by, the non-magnetic plate is interposed between the cores and between the cores at both ends and the window of the shield case, and the portion slidingly contacting the magnetic recording medium is composed of the core, the non-magnetic plate and the shield case. I am trying to do it.

[0007]

Therefore, even if the core holder is formed by casting at a low manufacturing cost, at least the surface of the shield case exposed to the window, which is in contact with the magnetic recording medium, is occupied by the core, the non-magnetic plate and the shield case. There is no die-cast product or resin with air bubbles, and no recess is formed on the surface with which the magnetic recording medium is in sliding contact. Further, since the non-magnetic plates inserted between the core and the core and between the core and the window of the shield case are set at predetermined intervals, the position of the core can be accurately determined.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below with reference to the embodiments shown in FIGS.

FIG. 1 shows an embodiment of the magnetic head of the present invention. This magnetic head is configured for a card reader. The core 1 and the magnetic shield plate 2 are held by a core holder 3 and housed in a shield case 4, and the tip of the core 1 and its surroundings are seen from a window 6 of the shield case. It is made to be exposed and hardened with resin 5 in the shield case 4.

The shield case 4 is for protecting the core 1 and the like from external noise, and the magnetic recording medium 9 on the front surface.
A window 6 is provided in a portion 10 in sliding contact with the core 10 to expose the core 1 and the like.

The core 1 is provided so that one gap G and a magnetic path are formed by abutting two halves 1a and 1b as shown in FIGS. 6A and 6B. . The core halves 1a and 1b have an asymmetrical shape. The coil 7 is wound around one half body 1a via an insulating layer, and the other half body 1b is not wound. And
The core half 1b on which the coil is not wound has a notch at a position corresponding to a portion around which the coil is wound, and the coil 7 wound on the adjacent core 1 is inserted into the notch 8 portion. It is provided so that the plurality of cores 1, 1 can be arranged very close to each other. Therefore, the four cores 1, ..., 1 are butted so that the core half 1a around which the coil 7 is wound and the core half 1b provided with the notch 8 are alternately arranged in the core width direction. For example, coil 7 and core half 1b
, 1 can be arranged in a narrow gap to form a magnetic head with a narrow track pitch. The core 1 is provided with a terminal 23 that is electrically connected to the coil 7 so as to project from the shield case 4.

The cores 1 at both ends between the cores 1 and at least the portion 10 in sliding contact with the magnetic recording medium 9.
A non-magnetic plate 11 is interposed between and the window 6 of the shield case 4. The non-magnetic plate 11 is obtained, for example, by punching a brass plate with a punching die. At this time, the non-magnetic plate 11 can be formed inexpensively and with high precision,
It is possible to accurately set the mutual positional relationship between the cores 1, ..., 1 and the positional relationship between the core 1 and the window 6 of the shield case 4. Of course, the non-magnetic plate 11 may be formed by cutting a brass material or the like. As with the core 1, the non-magnetic plate 11 may be used by abutting the two divided ones, or may be one. In this embodiment, one non-magnetic plate 11 is used between the core 1 and the window 6 of the shield case 4.

The core holder 3 has a window 6 of the shield case 4.
Of the core 1 and the core 1 so as not to be exposed at least in the portion 10 in sliding contact with the magnetic recording medium 9.
Between the core 1 and the core 1 and both ends of the core 1 and the shield case 4
Supports a non-magnetic plate 11 interposed between the window 6 and the window 6. The core holder 3 is not particularly limited, but is preferably made of a non-magnetic material cast product that can be easily manufactured at low cost, such as an aluminum die cast or a zinc die cast. The core holder holds the non-magnetic plate 11 interposed between the core 1 and the core 1 on the tip side and between the core 1 and the edge of the window 6 of the shield case 4. A support arm 15 for supporting the non-magnetic plate 11 and a rear wall portion 16 are provided at the tip of the core holder 3. Therefore, when the core halves 1a and 1b are opposed to each other, the support arm 15 and the rear wall portion 16 form the recessed portion 12, and the nonmagnetic plates 11 and 11 are housed and sandwiched in the recessed portion 12. Has been done. Further, when the space between the cores 1 is extremely narrow and the support arm 15 cannot be provided, the non-magnetic plate 11 is temporarily fixed directly to the cores 1 by adhesion or the like. The core holder 3 is provided with grooves (not shown) for inserting and supporting the cores 1, ..., 1 and the magnetic shield plates 2, 2 in a region below the support arm 15.

The magnetic head of this embodiment constructed as described above is constructed as follows.

First, the cores 1, 1, ..., 1 are inserted into the core holder 3 and held therein, and then the core 1 and the window 6 of the shield case 4 in the portion 10 sliding between the cores 1 and the magnetic recording medium 9 are held. The non-magnetic plate 11 is placed and temporarily fixed on the support arm 15 between the two. Also,
In the portion where the space between the cores 1 is small, the non-magnetic plate 11 is temporarily fixed by directly adhering it to the side surface of the cores 1. As a result, the core 1 and the core holder 3 are assembled with the non-magnetic plates 11, 11, 11 inserted between the four cores 1, 1, 1, 1 (see FIGS. 4 and 5). In FIG. 5, the non-magnetic plate 11 and the support arm 15 that supports the non-magnetic plate 11 are shown by hatching. Further, a magnetic shield plate 2 is set around the coil 7 of the core 1 as needed.

The assembled core holder 3 and core 1,
, 1 etc. are applied to the shield case 4 by applying one non-magnetic plate 11 on both sides, and are temporarily fixed by being pressed against one inner side surface 21 which is a test face by a screw 20.
In this temporarily fixed state, the resin 5 is filled and hardened from the back surface side of the shield case 4.

After the resin 5 hardens, the cores 1, ..., 1 protruding from the window 6 of the shield case 4, the non-magnetic plate 11, and the rear wall 16 of the core holder 3 are ground to a predetermined radius of curvature. Polishing is performed up to the position indicated by the dotted line in FIG. The cross-sectional shape of the core holder 3 after polishing is as shown in FIG. At this time, the non-magnetic plates 11 and 11 are interposed between the cores 1, ..., 1 and between the core 1 and the window 6 of the shield case 4 at least in the portion 10 in sliding contact with the magnetic recording medium 9. Then, the resin 5 is exposed only at the edge portion of the window 6 outside the portion 10 that is in sliding contact with the magnetic recording medium 9. , 1 on both sides of the gap G and grooves on the non-magnetic plates 11, 11 of the core holder 3 are respectively formed along the gap G, and the ceramic 22 is sprayed on the grooves to improve the wear resistance of the surface. Has been elevated.

In the magnetic head of this embodiment having the above structure, the tips of the cores 1, ..., 1 for four channels are exposed,
In the meantime, the non-magnetic plate 11 is inserted between the core 1 and the edge of the window 6 of the shield case 4. Therefore, the portion 10 with which the magnetic recording medium 9 is in sliding contact is occupied by the non-magnetic plate 11 and the shield case 4 that do not contain air bubbles, foreign matters, etc. in the cores 1, ..., 1 and the die cast parts and the resin 5 are present. There is nothing to do. Moreover, the surface of the head is finished smoothly by polishing.

The above-described embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention. For example, in the present embodiment, a 4-channel head is mainly described, but the present invention is not particularly limited to this, and the present invention can be applied to a 1-channel or 2-channel or more magnetic head. The non-magnetic plate 11 is not limited to brass, and may be non-magnetic material such as nickel silver or machined aluminum / phosphor bronze. In this embodiment, the gap between the core 1 and the core 1 or the gap between the core 1 and the window 6 of the shield case 4 is set by changing the plate thickness of the non-magnetic plate 11, but the plate thickness is constant. It is also possible to change the interval by changing the number of sheets used. Further, in this embodiment, the core holder 3 is partially exposed in the window 6 of the shield case 4, but it may be provided so as to be covered with the shield case 4 and not exposed in some cases.

[0020]

As is apparent from the above description, in the magnetic head of the present invention, the non-magnetic plate is provided between the cores and between the cores at both ends of the portion where the magnetic recording medium is in sliding contact and the window of the shield case. The core holder, the non-magnetic plate and the shield case are used to interpose the magnetic recording medium, and the core holder can be formed by casting such as aluminum die casting or zinc die casting, which is inexpensive to manufacture. Of the part exposed to the window of the shield case, at least the part in contact with the magnetic recording medium is occupied by the core, the non-magnetic plate and the shield case, and there is no die-cast product or resin with air bubbles. There is no risk of damage or clogging with magnetic powder. Further, since most of the core holder can be molded by casting which is inexpensive in manufacturing cost, cost reduction can be achieved.

Further, according to the magnetic head of the present invention, the non-magnetic plate inserted between the core and the core and between the windows of the shield case sets a predetermined distance between them. The position of the core is accurately determined.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an example in which the present invention is implemented as a magnetic head for a card reader.

FIG. 2 is a plan view showing the appearance of a magnetic head of the present invention.

FIG. 3 is a side view of FIG.

FIG. 4 is a front view showing an assembled state of the core and the core holder before being attached to the shield case.

5 is a sectional view taken along line VV of FIG.

FIG. 6 is a front view showing an example of a core, where (A) shows a core half with a coil wound, and (B) shows a core half without a coil wound.

FIG. 7 is a diagram showing an example of a conventional magnetic head, (A) is a plan view of the tape sliding contact surface as seen from above, (B) and (C).
FIG. 6 is a cross-sectional view illustrating a state in which a magnetic material is attached to a resin portion.

FIG. 8 is a diagram showing another example of a conventional magnetic head, FIG.
Is a plan view and (B) is a vertical sectional view.

[Explanation of symbols]

 1 core 3 core holder (aluminum die-cast product) 4 shield case 5 resin 6 window of shield case 9 magnetic recording medium 10 sliding part of magnetic recording medium 11 non-magnetic plate (brass die-cut product)

Claims (1)

[Claims] 1. A magnetic head in which a core is held by a core holder and accommodated in a shield case, a tip of the core is exposed from a window of the shield case, and the core is hardened with a resin in the shield case. A magnetic head characterized in that a non-magnetic plate is interposed between the core and the window of the shield case between the both ends and at both ends, and a portion in sliding contact with the magnetic recording medium is constituted by the core, the non-magnetic plate and the shield case.