JP2706028B2 - 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.
More particularly, the present invention is housed in a shield case to hold the core in the core holder, the tip of the core exposed from the window of the shield case and the magnetic head solidified with resin in the shield case, and in particular the core and the core The present invention relates to an improvement in a core holder of a magnetic head in which a gap or a gap between a core and a window of a shield case in a portion in sliding contact with a magnetic recording medium or a gap between both of them is small.

[0002]

2. Description of the Related Art A magnetic head as shown in FIG. 7, for example, is conventionally known as a magnetic head which positions a core by using a core holder, is housed in a shield case, and is solidified with resin. In this magnetic head, a pair of core halves 102, 102 respectively held by core holders 101, 101 are housed in a shield case 103 by abutting each other, and a resin 104 is placed around the core holder 101 and the core 102 in the shield case 103.
So that the tip of the core 102 is hardened while 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 runs, it comes into contact with the resin 104 exposed around the core 102 to generate frictional heat or static electricity. The applied coating material 107 adheres to the resin 104 to form a protrusion which causes spacing loss as shown in FIG. 7B or a core as shown in FIG. 7C. There is a problem in that the entire surface of the tip portion 102 is covered. In the drawing, reference numeral 108 denotes a magnetic shielding plate, and 109 denotes a coil bobbin.

Therefore, it has been conventionally considered to prevent the resin from being exposed to the portion that is in sliding contact with the magnetic recording medium. For example, as shown in FIG.
Of the core holders 201, 201,
201f is extended, and the window 205 of the shield case 203 is extended.
Exposed inside and in sliding contact with the magnetic recording medium 206
7, it is considered that the core 202 is surrounded by the core holder 201. Here, the core holder 201
Since it has a complicated shape having a groove for holding the core half 202 and a magnetic shielding plate (not shown) and a concave portion for forming a space for accommodating a coil bobbin and the like, it is generally formed by die casting. However, in the case of a head structure in FIG. 8, Te die-cast parts which include air bubbles
In the present situation, the entire core holder 201 is formed by shaving a brass material because a loop sliding surface cannot be formed. In this case, the core holder 201 is disposed around the core 202 exposed in the window 205 of the shield case 203, particularly in a portion 207 where the magnetic recording medium slides, and the resin 204 filled in the shield case 203 is not exposed. .

[0004]

However, when the core holder 201 is obtained by cutting out a brass material,
There is a problem that the cost increases because the processing takes time and the productivity also deteriorates. The cost is about 50 times as much as that in the case of die casting which is a general method of forming a core holder. When the core holder is manufactured by aluminum die-casting, since the aluminum die-cast part contains bubbles (about 2% in volume ratio), a concave portion due to the bubbles is formed on the polished surface / the surface of the portion 207 where the magnetic recording medium slides. This causes quality problems, such as damage to the magnetic recording medium and clogging of the concave portion with magnetic powder. Furthermore, in the case of a die-cast product, there is a problem that it is difficult to obtain accurate core position accuracy because high dimensional accuracy cannot be expected. In addition,
Like a magnetic head with a narrow pitch between tracks, the core 20
2 and the core 202 and the shield case 2 at the portion 207 which is in sliding contact with the magnetic recording medium or at the interval t ₁ between the core 202 and the core 202
Interval If t ₂ is narrow the window 205 of the 03, be obtained by cutting the comb-shaped core holder 201 provided with the thin partition wall, machining efficiency is poor and defective also difficult to process because it tends to occur is there.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic head which can be manufactured easily at a low cost and which can accurately position a core without quality problems such as generation of bubbles on a surface in contact with a magnetic recording medium. And In particular, the present invention is low-cost and easy even in a magnetic head having a narrow gap between cores or a gap between a core and a window of a shield case in a portion in sliding contact with a magnetic recording medium, such as a magnetic head having a narrow pitch between tracks. Another object of the present invention is to enable accurate positioning of the core without any quality problems such as generation of air bubbles on the surface in sliding contact with the magnetic recording medium.

[0006]

In order to achieve the above object, the present invention provides a method for holding a core with a core holder, housing the core in a shield case, exposing a tip of the core from a window of the shield case, and forming a resin in the shield case. in the magnetic head hardened, to and between the two ends of the core and the shield case of the window between the core and the core, and formic equal to these intervals thickness
The non-magnetic plate independent of each other in a direction perpendicular to the cap it
Each of the cores, the non-magnetic plate, and the shield case constitute a portion which is interposed therebetween and is in sliding contact with the magnetic recording medium.

[0007]

Therefore, even if the core holder is formed by casting at a low manufacturing cost, at least the surface of the portion exposed to the window of the shield case that is in contact with the magnetic recording medium is occupied by the core, the non-magnetic plate, and the shield case. In addition, there is no die-cast product or resin with air bubbles, and no recess is formed on the surface where the magnetic recording medium slides. In addition, the distance between the cores and the distance between the cores and the window of the shield case are set at predetermined intervals by a non-magnetic plate inserted therebetween, so that the positions of the cores are accurately determined.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of the present invention will be described below in detail 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. the exposed allowed to so that Ru hardened with resin 5 into the shield case 4.

The shield case 4 is for protecting the core 1 and the like from external noise.
A window 6 is provided at a portion 10 which is in sliding contact with the core 1 so as to expose the core 1 and the like.

The core 1 is provided so as to form one gap G and a magnetic path by abutting two core halves 1a and 1b as shown in FIGS. 6 (A) and 6 (B). I have. The core halves 1a and 1b have an asymmetric shape,
The coil 7 is wound on one half 1a via an insulating layer, and the coil is not wound on the other half 1b. A portion corresponding to a portion where the coil is wound is cut out in the core half 1b on which the coil is not wound, and the coil 7 wound on the adjacent core 1 is provided in the notch 8 portion. It is provided so that the plurality of cores 1 can be disposed so as to be extremely close to each other. Therefore, four sets of 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. If the plurality of sets of cores 1,..., 1 are arranged in a narrow gap without causing interference between the coil 7 and the core half 1b, a magnetic head having a narrow pitch between tracks can be formed. Note that the core 1 is provided with terminals 23 that are electrically connected to the coil 7 so as to protrude from the shield case 4.

The cores 1 at both ends between the cores 1 and at least in a portion 10 in sliding contact with the magnetic recording medium 9
And the distance between the window 6 of the shield case 4 and
In the direction having the same thickness and orthogonal to the gap G (FIG. 2)
(In the direction shown by the arrow))
1 is interposed, respectively. 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 at low cost and with high precision, and the mutual positional relationship between the cores 1,..., And the positional relationship between the core 1 and the window 6 of the shield case 4 can be accurately set. Becomes Of course, each non-magnetic plate 11 may be formed by cutting a brass material or the like. Each of the non-magnetic plates 11 can be used by abutting two divided ones as in the case of the core 1, or one can be used. In the case of 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 is provided with 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 which is in sliding contact with the magnetic recording medium 9.
Between core 1 and core 1 and shield case 4 at both ends
And the non-magnetic plate 11 interposed between the windows 6. The core holder 3 is not particularly limited, but is preferably made of a low-cost, easily manufactured non-magnetic material casting, such as an aluminum die-cast or a zinc die-cast. This core holder holds the non-magnetic plate 11 interposed between the core 1 and the core 1 and the edge of the window 6 of the shield case 4 on the distal end side. A support arm 15 for supporting the non-magnetic plate 11 and a rear wall 16 are provided at the tip of the core holder 3. Therefore, when the core halves 1a and 1b face each other, the concave portion 12 is formed by the support arm 15 and the rear wall portion 16, and the nonmagnetic plates 11, 11 are accommodated in the concave portion 12 and are sandwiched. Have been. When the distance between the cores 1 is extremely small and the support arm 15 cannot be provided, the non-magnetic plate 11 is temporarily fixed directly to the core 1 by bonding or the like. The core holder 3 is provided with a groove (not shown) for inserting and supporting the cores 1,..., 1 and the magnetic shielding plates 2, 2 in a region below the support arm 15.

The magnetic head of the present embodiment configured as described above is configured as follows.

First, the cores 1,..., 1 are inserted and held in the core holder 3, and then the core 1 and the window 6 of the shield case 4 between the cores 1 and the portion 10 which is in sliding contact with the magnetic recording medium 9 are formed. The non-magnetic plate 11 is inserted and temporarily fixed so as to be placed on the support arm 15 between the two. Also,
In a portion where the distance between the cores 1 is small, the non-magnetic plate 11 is temporarily fixed by directly bonding the non-magnetic plate 11 to the side surface of the core 1. Thus, 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 for supporting the non-magnetic plate 11 are indicated by hatching. The magnetic shielding plate 2 is set around the coil 7 of the core 1 as necessary.

The assembled core holder 3 and core 1,
, 1 etc. are inserted into the shield case 4 with one non-magnetic plate 11 applied to both sides and are temporarily fixed by being pressed against one inner side surface 21 serving as a demonstrative surface by screws 20.
In this temporarily fixed state, the resin 5 is filled from the back side of the shield case 4 and hardened.

After the resin 5 has hardened, 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 polished to a predetermined radius of curvature. Polishing is performed up to the position shown 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, non-magnetic plates 11, 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 which is in sliding contact with the magnetic recording medium 9. The resin 5 is exposed only at the edge of the window 6 outside the portion 10 in sliding contact with the magnetic recording medium 9. The cores 1,..., 1 on both sides of the gap G and the non-magnetic plates 11, 11 of the core holder 3 are each provided with a groove along the gap G. Has been enhanced.

In the magnetic head of this embodiment having the above configuration, the tips of the cores 1,...
A nonmagnetic plate 11 is inserted between the core 1 and the edge of the window 6 of the shield case 4. Therefore, the portion 10 where the magnetic recording medium 9 slides is occupied by the non-magnetic plate 11 and the shield case 4 in which the cores 1... Never do. In addition, the surface of the head is smoothed by polishing.

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

[0020]

As apparent from the above description, the magnetic head of the present invention, and between the magnetic recording medium opposite ends of the core and the shield case windows sliding contact portion between the core and the core, they Thickness equal to the gap and orthogonal to the gap
Interposed direction mutually independent, non-magnetic plate, respectively, the magnetic recording medium sliding contact portion of the core, since so as to constitute a non-magnetic plate and the shield case, inexpensive aluminum die casting or zinc die manufacturing cost core holder Even if it is molded by casting such as casting, at least the portion where the magnetic recording medium comes into contact with the window of the shield case is occupied by the core, the non-magnetic plate, and the shield case. Does not exist,
There is no risk of damaging the magnetic recording medium or clogging the magnetic powder. Further, since most of the core holder can be formed by casting, which is inexpensive to manufacture, the cost can be reduced.

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

[Brief description of the 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 the magnetic head of the present invention.

FIG. 3 is a side view of FIG. 2;

FIG. 4 is a front view showing an assembled state of a core and a core holder before being mounted on a shield case.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIGS. 6A and 6B are front views showing an example of a core, wherein FIG. 6A shows a core half with a coil wound, and FIG. 6B shows a core half without a coil wound.

FIGS. 7A and 7B are views showing an example of a conventional magnetic head, wherein FIG. 7A is a plan view of the tape sliding surface viewed from above, and FIGS.
FIG. 3 is a cross-sectional view illustrating a state where a magnetic material is attached to a resin portion.

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

[Explanation of symbols]

 Reference Signs List 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)

(57) [Claims] 1. A housed in the shield case to hold the core in the core holder, the magnetic head hardened with resin the tips of the core in the shield case is exposed from the window of the shield case, and the core and the core between the core and the shield case of the window between and both ends of these
Mutually equal in thickness and equal to the gap and perpendicular to the gap
A magnetic head comprising: a core, a non-magnetic plate, and a shield case, each of which has an independent non-magnetic plate interposed therebetween, and a portion in sliding contact with a magnetic recording medium.