JPH02197103A - Flat coil - Google Patents

Abstract

PURPOSE:To prevent a conductive foil from corrosion as well as to prevent generation of careless short circuit by a method wherein an oxide insulating film layer is formed on the exposed surface of the conductive foil of a laminated body on which a flat coil will be formed. CONSTITUTION:A flat coil is formed by winding the laminated body of an insulating layer and conductive foil, and by cutting it into the prescribed thickness by conducting electrospark machining. When the exposed surface of the conductive foil of said flat coil is oxidation-treated, the surface of the conductive foil is turned into an insulative oxide layer, the corrosion of the conductive foil can be prevented, and at the same time, a carelessly generating short circuit can also be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a flat coil used in motors, deflection yokes, transformers, etc.

[Summary of the invention]

The present invention provides a flat coil made by winding a laminate of an insulating layer and a conductive foil and cutting it to a predetermined thickness. [Prior Art] Conventionally, flat coils have been used as motor coils and deflection yokes for cathode ray tubes, as they have a large conductor occupation rate, have a simple structure, and are easy to manufacture. This flat coil is formed by winding a laminate of an insulating layer made of an adhesive or the like and a conductive foil made of aluminum or the like, and cutting the wound body into rounds to a predetermined thickness using a method such as electrical discharge machining. It is something that will be done.

By the way, in such a flat coil, since the conductor foil is exposed on the outermost circumferential surface and the cut surface, it has poor moisture resistance and is easily oxidized. Also, when mounting this flat coil on a printed circuit board, for example,
There is a risk of an inadvertent short circuit with the conductor circuit of the printed circuit board.

Therefore, in order to solve these problems, the applicant coated the cut surface with an insulating adhesive or insulating paint as previously described in Japanese Patent Application No. 62-46430. It has been proposed that an insulating film or the like be attached to the conductor foil to prevent oxidation and insulate it, as described in Japanese Utility Model Application No. 101476/1983.

[Problem to be solved by the invention]

However, with the above method, uneven application of the adhesive or poor adhesion of the insulating film may occur, and at present, oxidation prevention and insulation cannot be achieved reliably. Moreover, the work of applying an insulating adhesive or insulating paint, or pasting an insulating film or the like after cutting the wound body is very troublesome and complicated. For this reason, it is difficult to manufacture inexpensive flat coils with good productivity.

Therefore, the present invention has been proposed in view of the conventional situation, and provides a highly reliable flat coil that can prevent corrosion and prevent accidental short circuits, as well as improve productivity. Our aim is to provide superior flat coils.

Means for Solving Problem C8] The present invention has been proposed in order to achieve the above-mentioned object, and includes a flat film made by winding a laminate of an insulating layer and a conductive foil and cutting it to a predetermined thickness. The coil is characterized in that the exposed surface of the conductor foil is oxidized to form an insulating oxide layer.

[Effect]

In the flat coil according to the present invention, since the outer surface of the wound body, that is, the surface of the conductor foil exposed at the outermost peripheral surface and the cut surface is oxidized, the surface of the conductor foil becomes an insulating oxide layer. Since this insulating oxide layer is a passive film formed by chemical treatment, it is formed evenly and has both moisture-resistant and insulating functions even if it is thin. Therefore, when the flat coil is mounted on a printed circuit board or the like or when the flat coils are stacked on top of each other, inadvertent short circuits are prevented.

Moreover, according to the flat coil according to the present invention, there is no need to apply an insulating adhesive or stick an insulating film to ensure insulation, and all the parts exposed on the outer surface are oxidized. Since the insulating oxide layer is formed evenly over the surface of the conductor foil, it can be manufactured without any complicated steps, and productivity can be improved.

〔Example〕

Hereinafter, specific embodiments to which the present invention is applied will be described with reference to the drawings.

As shown in FIGS. 1 and 2, the flat coil of this embodiment has an insulating layer (1) and a conductor f! It is constructed by cutting a wound body (3) formed by winding the laminate (2) until the desired characteristics are obtained and cutting it to a predetermined thickness.

The laminate of the insulating layer (1) and the conductive foil (2) is constructed by laminating an adhesive or the like onto the conductive foil (2) made of a conductive metal material.

Examples of the material for the conductive foil (2) include aluminum, nickel, stainless steel, tin, and zinc.

Examples include phosphor bronze and 1 lead, among which aluminum is more suitable and practical since it is light in weight.

In addition to the structure described above, the structure of the laminate of the insulating layer (1) and the conductive foil (2) may be, for example, as shown in FIG. and an insulating layer (42) on both sides of the conductor foil (41).

Furthermore, as shown in FIG. 8, in order to ensure more reliable insulation, a polymer film (44) such as a polyimide film may be formed with two layers of insulation. Conductive foil (
47) may be laminated.

The laminated body of the insulating layer (1) and the conductive foil (2) is wound with the insulating layer (1) inside. Therefore, the insulating layer (1) is exposed on the innermost peripheral surface of the wound body (3), and the conductor foil shaft is exposed on the outermost peripheral surface. Moreover, the cut surface (3a) of the said wound body (3).

(3b), the insulation N (1) and the conductive foil (2) are exposed.

In particular, in this embodiment, the outer surface of the wound body (3), that is, the outermost periphery (3) and the cut surfaces (3a) (3b)
The surfaces of the conductor foil (2) exposed to the respective surfaces are oxidized to form an insulating oxide layer (2a) and an insulating oxide layer (2b).

(2c). In FIGS. 1 and 2, for convenience, insulating oxides 71 (2b) and (2c) are formed as layers on the cut surfaces (3a) and (3b). However, in reality, the cut surface (3
Only the surface portion of the conductor foil (2) exposed in a) and (3b) is oxidized. the insulating oxide layer (2a),
(2b) and (2c) are the above conductors Pi! f(2)
It is formed by chemical treatment, for example, by immersing it in an oxalic acid aqueous solution and applying a direct current to anodize it for a predetermined period of time. Therefore, the above-mentioned insulating oxide layers (2a), (2b),
(2c) becomes a passive film. Furthermore, since the film thicknesses of the insulating oxide layers (2a), (2b), and (2c) are extremely thin, there is no risk of reducing the conductor occupancy of the conductive foil (2). Jig (2a)
.

(2b) and (2c) are thin (both have high insulation properties).

In this way, the conductor foil (
2) are all insulating oxides Ji (2a), (2b)
, (2c), it is less likely to be corroded and also prevents an inadvertent short circuit. In addition, by simply oxidizing the conductor foil (2), insulating oxidation J! with high reliability can be achieved.
Since (2a), (2b), and (2c) are easily formed, they can be produced without any complicated steps, which is suitable from the viewpoint of productivity.

Furthermore, when the flat coil is mounted on a printed circuit board, for example, as shown in FIGS. 9 and 10, the insulating oxide film (2) on the cut surfaces (3a) and (3b) is
b) An insulating adhesive or insulating adhesive having both insulating and adhesive properties is applied onto (2c), and an insulating layer (4) consisting of these insulating adhesive layer or insulating adhesive layer is formed.
a) and (4b) may be formed.

When the above insulating adhesive is used, it can be easily mounted on a printed circuit board simply by applying heat using a heating jig to soften the insulating adhesive. In this case, it is necessary to be careful not to deform the printed circuit board itself since heat is applied. On the other hand, when using an insulating adhesive,
It can be easily and quickly mounted on a printed circuit board by applying light pressure without heating. Therefore, the latter is advantageous in terms of jigs, deformation, etc. Of course, since the insulating layers (4a) and (4b) have excellent insulating properties, the insulating properties of the cut surfaces (3a) and (3b) are further improved.

The insulating layers (4a) and (4b) are replaced by the insulating oxide film (2b).

(2c) For example, the formation is performed as follows.

First, as shown in FIG. 11(a), a recess (52) having the same shape as the cut surfaces (3a) and (3b) is provided in the jig (51), and an insulating material, for example, is provided in the recess (52). Inject the adhesive <S>. In addition, the above-mentioned insulating adhesive (S
), an insulating adhesive may also be used.

Next, as shown in FIG. 11(b), the recess (52)
The recess (52) is removed by sliding the blade (53) in the direction of arrow C in the figure on the jig (51) provided with the recess (52).
Scrape off the excess adhesive (S) that sticks out.

This removes excess adhesive (S) from the transfer jig (54), which will be described later.
) to prevent adhesion.

Next, as shown in FIG. 11(c), a transfer jig (54) made of a rubber material such as silicone rubber is inserted into the recess (5).
2) from above toward the recess (52) (in the direction of the arrow in the figure), pressurized, and then raised again (in the direction of the arrow E in the figure).

Through this operation, the adhesive (S) injected into the recess (52) is transferred to the surface of the transfer jig (54),
The adhesive (S) is attached in the same shape as the cut surfaces (3a) and (3b) of the flat coil.

Next, as shown in FIG. 11(d), the transfer jig (54) is moved onto the positioned flat coil and lowered in the direction of arrow F in the figure to apply pressure.

Next, as shown in FIG. 11(e), the transfer jig (
54), the adhesive (S) is applied onto the insulating oxide layer (2b) of the flat coil.

As a result, an insulating layer N (4a) made of an adhesive layer is formed on the insulating oxide layer (2b). Of course, by repeating these steps, an insulating layer (4a) is formed on both sides.
, (4b) is formed.

Here, in order to make the structure of the flat coil of this example more clear, the manufacturing method thereof will be explained in the order of steps with reference to the drawings.

First, 3% by volume of aluminum foil, which is the raw material for the flat coil, is
The sample was immersed in a dilute sulfuric acid solution at a temperature of 65°C for 5 minutes to remove dust and other impurities adhering to the surface, then washed with water and dried at room temperature.

The above aluminum foil is manufactured by Nippon Seifaku Co., Ltd., product name AIH-0-
25-RT was used, and the film thickness was 25 μm.

Next, the aluminum foil was immersed in a 10% by volume oxalic acid aqueous solution at a temperature of 35°C and heated at 45 V r 1.5 A.
/ d m ' and anodized for 5 minutes to form an extremely thin layer (approximately 1 μm) as shown in Figure 3.
An insulating oxide layer (21a) was formed on one side of the aluminum foil (21).

Next, the obtained aluminum Wi (21) was washed with water and dried at room temperature.

Next, water vapor at 3 atm was applied to the surface subjected to the anodizing treatment (i.e., the insulating oxide layer (21a)) at 2
The insulating oxide layer (21a) was applied for 0 minutes to perform a sealing treatment to make it dense.

The insulating oxide layer (21a) exhibits excellent insulating properties even if it is as thin as 1 μm, so it is possible to reduce the thickness of the insulating layer made of adhesive in the subsequent process. The conductor occupancy rate can be obtained.

In this embodiment, the aluminum foil (21) is anodized for the purpose of further improving the reliability of insulation, but it is not necessarily necessary to perform anodization here.

Next, the insulating oxide layer (21a) of the aluminum foil (21) is
An adhesive (22) having the following composition was applied on top so that the film thickness after drying was 10 tIm, and then heated at 140°C for 30 minutes.
The solvent was removed by drying for a minute.

Adhesive composition: Epoxy resin 100 parts by weight (manufactured by Dainippon Ink Co., Ltd.; trade name Evicron E-152) Epoxy resin 40 parts by weight (manufactured by Yuka Shell Epoxy Co., Ltd.; trade name Epicote 872) Nitrile butadiene rubber 30 parts by weight ( NBR
) (manufactured by Nippon Zeon Co., Ltd.; trade name Hiker 41001) phenolic resin 25 parts by weight (manufactured by Maruzen Sekiyu Co., Ltd.; trade name Resin MB) 2-undecyl imidazole 1 part by weight dicumyl peroxide 1 part by weight [each of the above substances was used as a solvent] An adhesive was prepared by mixing in a proportion of 30% by weight with respect to methyl ethyl ketone (MEK). ] Coating the adhesive (22) having the above composition is carried out, for example, using an adhesive coating device. That is, the conductive foil (21) supplied from the unwinding roll is guided to the adhesive coating machine, and the insulating oxide layer is coated with the adhesive (22). (21a) is coated with an adhesive (22) having the above composition.6 Next, the conductor M (21) coated with this adhesive (22) is passed through a dryer to
) to dry the adhesive (22) and the conductor fi
! A raw fabric roll (23) of a laminate consisting of 1 (21) is formed.

Next, as shown in FIG. 5, after the raw fabric roll (23) is slit to a predetermined width, it is delivered from an unwinding roll (24) and is fed with pack tensidin by a tension roll (25). A predetermined number of rolls are wound around a central shaft (26) having a substantially triangular cross section with the agent layer (22) on the inside to form a wound body of the raw roll laminate.

Here, heat rolls (28), (28), (
28) is crimped from three sides to adjust the winding condition of the wound body.

In addition, the above heat rolls (28), (28), (2
8), the adhesive (22) is attached to the conductive foil (
21) and is firmly bonded.

Note that the cross-sectional shape of the central axis (26) may be matched to the desired coil shape, such as a circular shape or an elliptical shape.

It can have various shapes such as a polygon.

Then, the obtained coil block (29) was heated to 150°C.
The adhesive layer (22) interposed between the eyebrows of the rolled body is softened by placing it in a heating oven for 30 minutes.
and the conductor foil (21) are brought into close contact with each other and then hardened to produce a strong laminated winding.

Next, the coil block (29) is cut into predetermined intervals by electrical discharge machining to form flat coils.

In order to perform the cutting process by electric discharge machining, for example, as shown in FIG. 6, a container (31
), the coil block (29) is immersed in the center shaft (
26) Plate electrodes (3
2) A pulse current may be applied. As machining* (30) during electric discharge machining, water or a petroleum-based machining fluid (for example, kerosene, etc.) can be used.

Note that the means for cutting the coil protrusion (29) is not limited to the electric discharge machining method described above, and for example, a method of cutting by mechanical means, a method of cutting using a wire, etc. can be applied, and any desired method can be used. Any means may be used as long as it can cut to a thickness of .

Next, the flat coil cut to the desired thickness was immersed in a 3% by volume diluted sulfuric acid solution at a temperature of 65°C for 5 minutes to remove impurities such as cutting powder, then washed with water and dried at room temperature. Ta.

Next, the flat coil was immersed in a 10% by volume oxalic acid aqueous solution at 35°C, and heated at 45V and 1°5A/dm.
After anodizing for 5 minutes by applying a direct current of 1, it was washed with water and dried at room temperature.

Finally, water vapor at 3 atmospheres was applied to the insulating oxide layer formed by the above-mentioned anodic oxidation treatment for 20 minutes to perform sealing treatment to make the insulating oxide layer dense.

As a result, all of the conductor foil (21) exposed on the outer surface (cut surface and outer circumferential surface) of the flat coil was oxidized to form a highly insulating oxide layer.

The flat coil thus obtained had excellent insulation properties and a high conductor occupation rate, and was useful as a flat coil used in motors, deflection yokes, transformers, etc.

〔Effect of the invention〕

As is clear from the above description, according to the flat coil of the present invention, since the surface of the conductor foil exposed on the outer surface is made of an insulating oxide layer, it is not easily corroded and exhibits high insulating properties. Therefore, when this flat coil is mounted on a printed circuit board or the like or when flat coils are stacked on top of each other, inadvertent short circuits are prevented.

In addition, in the flat coil of the present invention, an insulating oxide layer with excellent moisture resistance and insulation properties is formed uniformly over the entire outer surface by simply oxidizing the conductor foil, so no complicated process is involved. It becomes possible to provide highly reliable flat coils with excellent moisture resistance and insulation properties at low cost and with good productivity.

Furthermore, since the insulating oxide layer exhibits excellent moisture resistance and insulation properties even if it is thin, it does not reduce the conductor occupancy of the conductor foil.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing an example of a flat coil to which the present invention is applied, and FIG. 2 is a schematic sectional view taken along line A--A in FIG. 1. Figures 3 to 6 show an example of a method for manufacturing a flat coil according to the order of the steps. Figure 3 is an enlarged sectional view of the main part showing the step of forming an insulating oxide layer, and Figure 4 is the adhesive application step. FIG. 5 is a schematic side view showing the coil winding process, and FIG. 6 is a schematic side view showing the electrical discharge machining process. FIG. 7 is an enlarged sectional view of main parts showing another example of a laminate of flat coils according to the present invention, and FIG. 8 is an enlarged sectional view of main parts showing still another example of a laminate. In FIG. 9, an insulating layer is formed on an insulating oxide layer. FIG. 11(a) to FIG. 11(e) are enlarged cross-sectional views of essential parts showing an example of a method for forming an insulating layer on an insulating oxide layer on a cut surface of a flat coil along the process order,
Figure 11(a) shows the process of filling the adhesive into the recess;
b) shows the process of scraping off the adhesive, FIG. 11(c) shows the process of transferring the adhesive to the transfer jig, FIG. 11(d) shows the process of transferring the adhesive to the flat coil, and FIG. ) indicate the state of the flat coil after transfer. 1 ・ ・ 2 ・ 3 ・ 3a. 4a.・Insulating layer・Conductor foil・Wound body 3b...Cut surface 4b...Insulating oxide layer Patent applicant Sony Chemical Co., Ltd. Representative Patent attorney Miumi Koike Eido Tamura Masaru Sato Figure 2 Figure 7 Figure 8 Figure 9 Figure 10

Claims (1)

[Claims] A flat coil made by winding a laminate of an insulating layer and a conductive foil and cutting it to a predetermined thickness, the flat coil characterized in that the exposed surface of the conductive foil is oxidized to form an insulating oxide layer. .