JPH1169684A - Printed coil for actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain thin insulating layers, stable insulating properties and the maintenance of a conductor pattern by composing a printed coil of the insulating layers burying sections among the conductors of a plurality of conductor wiring patterns, film layers ensuring the mechanical strength of sections among the insulating layers and adhesive layers directly bonding films and the conductors. SOLUTION: A plurality of conductor wiring pattern 1 layers are composed of insulating layers (first insulating layers: varnish) 2 being directy joined with the conductors of the conductor wiring pattern 1 layers and burying sections among the conductors, film 4 layers for ensuring insulation among the layers and mechanical strength and adhesive layers (second insulating layers) 3 directly bonding the films 4 with the conductors. The first insulating materials (varnish) bury sections among at least the conductor wiring patterns 1 in the half or more of conductor thickness at that time, and an epoxy resin, a polyester resin, an acrylic resin, etc., are used generally as the second insulating materials (the adhesive layers). The thickness of a filmy insulating base material is set in 20 μm or less, a modulus in tension in 250 kg/mm<2> or more and dielectric breakdown strength in 200 kV/mm<2> or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed coil for an actuator, and more particularly to a method of improving a thrust and a torque of an actuator by improving an insulating layer.

[0002]

2. Description of the Related Art As actuators, particularly motors, have become thinner, printed coils using photolithography technology have been widely used from coil windings.
For example, as shown in FIG. 4, the actuator makes use of the feature that the print coil is thin, and the gap between the magnet 5 and the yoke 7 arranged with the coil 6 interposed therebetween can be made very narrow. Further, as shown in FIG. 5, since the coil arranged in a plane is a spiral coil 8, the central part of the spiral is connected to the back surface by a through hole 9, and is drawn out of the spiral while drawing the spiral again. In addition, through-holes are used to prevent the leading lines connecting the coils from interfering with other patterns.

On the other hand, compared with an actuator using a conventional winding, the magnetic field at the position of the coil can be extremely increased by reducing the gap between the magnet and the yoke and using a strong magnet. is there. In particular, even if the gap is reduced by several tens of μm, the characteristics are greatly improved. Therefore, it is important how the print coil can be made thin.

[0004]

In order to reduce the thickness of the insulating layer, Japanese Unexamined Utility Model Publication No. 29526/1992 discloses that an adhesive for holding a conductor wiring pattern is caused to flow by heat, insulation between layers is secured by a film, and By eliminating the adhesive between the conductor and the film, the interlayer thickness of the conductor wiring is reduced to the film thickness. FIG. 3 is a schematic view showing the cross section.

[0005] However, since the film and the adhesive are lost due to the flow of the film and the adhesive, the resin is held only in the side surface by the resin filled in the surface direction of the conductor. In such a case, the ratio of the area held and adhered to the conductor area is very small, resulting in insufficient strength. Further, the insulating base material is made of a slight adhesive material between the film and the side surface of the conductor, and becomes extremely weak as the coil itself, and undergoes a reaction force for rotating the rotor of the motor, causing deformation and vibration.

[0006] On the other hand, although the purpose is different, Japanese Patent Publication No. 2-3187
In Japanese Patent Application Laid-Open No. 5 (1993) -1993, in order to ensure reliability between conductor layers, a technique is used in which the conductor lamination surface and the space between the conductors are filled with a first insulating material, and in particular, bonded to another substrate with a second insulating material without another insulating material. It has been disclosed. FIG. 2 is a schematic diagram showing the cross section. Here, in order to prevent foreign substances and contaminants from being involved in bonding to another substrate, a method of covering the substrate with a first insulating material in advance is adopted.

According to this method, there is no problem in the case of a printed circuit board whose thickness is loosely limited. However, although the insulation reliability between the laminations is improved, the lamination between the first insulating material and the second insulating material becomes extremely thick. . When this method is applied to an actuator coil, the following problems arise. In order to reduce the thickness while maintaining the cross-sectional space factor of the conductor, which is the most important characteristic of the printed coil for an actuator, there is in principle a method only by reducing the thickness with an insulating material.

Therefore, if the first insulating material is made thinner at the top of the conductor, it becomes difficult to fill the space between the conductors. Therefore, it is easier to make the second insulating base thin. However, when the second insulating material is bonded and cured on the first cured insulating material, a sufficient bonding strength cannot be obtained unless some surface treatment is performed. Further, since the second insulating material is thin, the stability of the adhesive cannot be secured due to the slight unevenness of the first insulating material, and the insulating property of the material itself is hardly reached due to the influence of the unevenness of the base.

As described above, since the insulating base material is composed of the two layers of the first insulating material and the second insulating material, there are many difficulties in thinning the insulating layer and stabilizing the adhesion. Accordingly, the present invention provides a structure in which the thickness of the insulating layer is small, the adhesive strength between the conductor and the insulating layer is secured, and the strength as a printed coil is maintained, and a method of manufacturing the same.

[0010]

A printed coil for an actuator according to the present invention has at least one conductive wiring pattern, and a first insulating material existing between the conductive wiring patterns, and the conductive wiring pattern and the first insulating material. A second insulating material for directly joining a portion facing the insulating base material, and a printed coil for an actuator in which the insulating base material corresponding to the conductor wiring pattern is composed of one or more layers, wherein the first insulating material is at least The gap between the conductors of the conductor wiring pattern is filled with 以上 or more of the conductor thickness, and the second insulating material has a thickness of 1 to 20 μm.

If the thickness of the first insulating material is less than 1/2 of the thickness of the conductor, there is a problem that it is difficult to secure insulation reliability between wires, and that voids of the second insulating material at the time of bonding increase sharply. . Naturally, it is more preferable to fill the same thickness as the conductor thickness, that is, to fill all the spaces between the lines. If the thickness of the second insulating material directly joined is less than 1 μm, the cause is not well understood,
The bonding strength is extremely reduced and only the same strength can be obtained without the bonding layer. When the thickness of the second insulating material exceeds 20 μm, the thickness is accumulated in each layer in the multilayer structure,
The print coil as a whole becomes sharply thicker, and the distance between the magnet and the yoke must be increased in forming a motor or the like. As a result, the magnetic field at the coil position is weak,
The motor output will drop. Preferably 1 to 10 μm
It is.

The second insulating material serves as an adhesive layer, and the resin used may be any resin as long as the insulating property and the adhesiveness to copper / resin can be ensured. In general, epoxy resin, polyester resin, acrylic resin and the like are used. You. The method for forming the adhesive layer is not particularly limited, but roller coating, dip coating, screen printing and the like are used. In the case of multi-layer lamination, if the thickness is 10 μm, the thickness will be 20 μm if it is two layers.
It becomes 0 μm thick and causes a significant decrease in the magnetic field. Therefore, the present invention exerts its effect particularly with a coil having two or more layers.

[0013] The insulating base material is in the form of a film, and preferably has a thickness of 20 µm or less. Furthermore, it is preferable that the tensile modulus is 250 kg / mm ² or more and the dielectric breakdown voltage is 200 Kv / mm or more.
If the tensile modulus is less than 250 kg / mm ² , the printed coil is too thin to bend, and thus becomes weak against bending. This causes unnecessary vibration of the coil and increases the noise of the entire set. As for the dielectric breakdown voltage, if the thickness of the resin portion between the conductor layers is reduced, it is difficult to maintain the interlayer insulation as a coil, and the insulation characteristics as an insulation layer in a later-formed conductor pattern such as an adhesive layer. It is difficult to maintain the uniformity of the film, and it is important to secure the insulating properties in the film layer. Therefore, the dielectric breakdown voltage of the film used must be 200 Kv / mm or more. Further, in the present invention, it is preferable that the insulating base material contains an aromatic polyamide.

The present invention is characterized in that the joint surface of the conductor wiring pattern directly joined to the second insulating material has been subjected to a physical polishing treatment. Here, the physical polishing treatment may be any polishing as long as it is performed by a mechanical method, and general buff polishing, polishing using a belt sander or a grindstone using sandpaper, or the like is preferably used. The method of manufacturing a printed coil according to the present invention includes a step of applying an insulating material to the substrate on which the conductor wiring pattern is formed, and polishing the surface on which the insulating material is applied to partially remove the insulating material on the surface of the conductor. And bonding the substrate on which the conductive wiring pattern is formed to an insulating film with an adhesive.

In particular, the effect of reducing the overall thickness by applying an insulating base material first and then polishing it, of course, the effect that the thickness unevenness in the substrate is flattened by polishing, and the more remarkable effect is the underlying copper layer Can be bonded directly to an adhesive to be used later, or the surface of the insulating layer formed first can be roughened by polishing, which strengthens the joint and withstands the stress of cutting performed by the mold later. Structure.

As described above, the present invention provides an insulating layer (first insulating layer) for directly joining a plurality of conductor wiring pattern layers to the conductors and filling between the conductors, and a film for securing insulation between layers and mechanical strength. For the first time, it was possible to secure a thin insulating layer, a stable insulating property, and a holding property of a conductive pattern by only including the layer and an adhesive layer (second insulating layer) for directly bonding the film and the conductor.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to examples and comparative examples, but is not limited to the examples. Here, an example of a brushless motor coil will be described as an actuator coil.

[0018]

Embodiment 1 A resist pattern is formed on an aluminum foil, which is a conductive substrate, except where it becomes a conductor, and then electrolytic copper plating is performed so as to deposit a necessary amount of copper. Thereby, the conductor pattern portion has a conductor thickness of 35 μm, and the conductor interval is 2 mm in the coil portion.
It was 0 μm. Therefore, an insulating varnish (WI-640 manufactured by Hitachi Chemical Co., Ltd.), which is the first insulating material, is applied to the conductor gap (width 20).
.mu.m, depth 35 .mu.m). Thereafter, the varnish was cured at 130 degrees for 60 minutes.
Next, the side of the board where the conductor pattern is located is WX # made by Kakuda Brush.
Polishing was performed with a 320 buff until the varnish at the highest point of the plated conductor was removed.

Thereafter, 7 g of an epoxy adhesive EP-170 manufactured by Cemedine Co. was applied to the polished surface by screen printing. After heating at 120 ° C. for 7 minutes after the application, 4.5 μm of an aromatic polyamide film (trade name: Aramica) manufactured by Asahi Kasei Kogyo Co., Ltd., which is an insulating base material, was pressed.
Aramica used has a tensile modulus of 1500 kg / m
m ² and the dielectric breakdown voltage is 230 KV / mm.

The press is operated at an initial heating rate of 2 degrees / minute and a pressure of 1
Pressing was performed at 0 kg / cm ² . 60 at 135 ° C
After the minute pressing, the pressure was released after the substrate temperature was lowered to 60 degrees. Next, the aluminum substrate was removed by etching with hydrochloric acid 8% for 30 minutes. The obtained substrate was punched into a coil shape for a brushless motor using a mold. As a result, out of the 500 obtained coils, the number of the adhesive layers peeled off after punching was 0. Further, 20 pieces were randomly sampled, the cross section was cut, and the distance between the conductors sandwiching the film was measured. The result was 14.5 μm on average. As shown in FIG. 1, about 5 μm of the adhesive layer 3 was present on both sides of the 4.5 μm film 4.

Further, 20 samples are sampled and 20 mm
As a result of measuring the displacement at the center when the center was bent by 100 g at the center with the distant points as two supporting points, the average was 1.2.
mm. Further, the above-described substrate was manufactured in the same process until punching out with a mold, and two obtained substrates were laminated to obtain a four-layer substrate. In this step, after etching the aluminum substrate, the surface is polished once again with a WX # 320 buff manufactured by Kakuda Brush, and the polished surface is coated with an epoxy adhesive EP- manufactured by Cemedine.
170 was applied by 7 g screen printing. 120 after application
After heating at a temperature of 7 minutes, 4.5 μm of an aromatic polyamide film (trade name: Aramica) manufactured by Asahi Kasei Corporation
Then, the two etched substrates were pressed.
As a result, a substrate having four conductor layers was obtained. The obtained substrate was similarly punched with a mold, but among the 500 obtained coils, none of the coils had the adhesive layer peeled off after punching. When the thickness of 100 pieces was measured, it was 184 μm on average.

The coil has a magnetic flux density Br = 11000 Ga.
When mounted on a motor having a uss magnet, the yoke distance can be set to 0.5 mm from the coil thickness, and the torque constant is 48.
Performance of 1 gcm / A was obtained.

[0023]

Example 2 A substrate was prepared in exactly the same manner as in Example 1 except that aramica having a thickness of 12 μm was used. The obtained substrate was punched into a coil shape for a brushless motor using a mold. After punching out of 500 of the resulting coils, no adhesive layer was peeled off. Moreover, 20 pieces were randomly sampled, the cross section was cut, and the distance between the conductors sandwiching the film was measured. The result was 22.2 μm on average. As shown in FIG. 1, each 5.1 μm adhesive layer 3 was present on both sides of the 12 μm film 4.

Further, 20 samples were sampled and 20 mm
As a result of measuring the displacement of the central part when the center was bent 100 g at the center with the distant points as two fulcrums, the average was 1.0.
mm.

[0025]

Example 3 12 μm polyimide film (trade name: Kapton) manufactured by Toray Dupont Co., Ltd.
A substrate was prepared in exactly the same manner as in Example 1 except that the substrate was used.
Kapton used has a tensile modulus of elasticity of 300 kg / mm
² , and the dielectric breakdown voltage is 280 KV / mm.

The obtained substrate was punched out by a mold into a coil shape for a brushless motor. As a result, the obtained coil 5
After punching out of 00 pieces, the adhesive layer was peeled off.
Was individual. In addition, 20 samples are randomly sampled,
The cross section was cut, and the distance between the conductors sandwiching the film was measured. The result was 22.5 μm on average. As shown in FIG.
The adhesive layer 3 of about 5.25 μm was present on both sides of the 12 μm film 4.

Further, 20 samples were sampled and 20 mm
As a result of measuring the displacement at the center when the center was bent by 100 g at the center with the distant points as two supporting points, the average was 1.2.
mm.

[0028]

Example 4 A polyimide film (trade name: Kapton) manufactured by Toray Dupont Co., Ltd.
A substrate was prepared in exactly the same manner as in Example 1 except that m was used. The Kapton used has a tensile modulus of elasticity of 300 kg /
mm ² and the dielectric breakdown voltage is 280 KV / mm.

The obtained substrate was punched into a coil shape for a brushless motor using a mold. The resulting coil 50
After punching out of 0 pieces, there were 0 pieces where the adhesive layer was peeled off. In addition, 20 samples were randomly sampled, the cross section was cut, and the distance between the conductors sandwiching the film was measured. The result was 36.1 μm on average. As shown in FIG.
about 5.55 μm of adhesive layer 3 on both sides of a μm film 4
Existed.

Further, 20 samples were sampled and 20 mm
As a result of measuring the displacement at the center when the center was bent at 100 g at the center with the distant points as two fulcrums, the average was 1.1.
mm.

[0031]

COMPARATIVE EXAMPLE 1 A resist pattern is formed on an aluminum foil as a conductive substrate except where it becomes a conductor, and then electrolytic copper plating is performed so as to deposit a required amount of copper. As a result, the conductor pattern portion has a conductor thickness of 35 μm, and the conductor interval is 2
It was 0 μm. Next, insulating varnish (WI-6 manufactured by Hitachi Chemical)
40) was applied by dip coating so as to fill the preceding conductor interval (width 20 μm, depth 35 μm). Thereafter, the varnish was cured at 130 degrees for 60 minutes.

Thereafter, 3.5 g of an epoxy adhesive EP-170 manufactured by Cemedine Co. was applied to the varnish surface by screen printing. After heating at 120 ° C. for 7 minutes after the application, a polyimide film (trade name: Kapton, manufactured by Toray DuPont Co., Ltd.) of 25 μm was pressed therebetween during the pressing. The Kapton used has a tensile modulus of 300 kg / mm ² and a dielectric breakdown voltage of 280 KV / mm.

The press was initially heated at a rate of 2 ° C./min.
Pressing was performed at 0 kg / cm ² . 60 at 135 ° C
After the minute press, pressurization was continued until the substrate temperature reached 60 degrees. The aluminum substrate was removed by etching with 8% hydrochloric acid for 30 minutes. The obtained substrate was punched into a coil shape for a brushless motor using a mold. The resulting coil 50
After punching out of 0 pieces, 27
There were zero. Moreover, 20 pieces were randomly sampled, the cross section was cut, and the distance between the conductors sandwiching the film was measured. The result was 49.7 μm on average. As shown in FIG.
Adhesive layer 3 on both sides of 25 μm film 4 is 2.35 μm
And 10 μm of varnish 2 was present thereon.

Further, 20 samples were sampled and 20 mm
As a result of measuring the displacement of the central part when it was bent at 100 g at the center with two fulcrums as the fulcrum, the average was 3.5 m.
m. Further, the above-described substrate was manufactured in the same process until punching out with a mold, and two obtained substrates were laminated to obtain a four-layer substrate.

In the process, after etching the aluminum substrate, 3.5 g of epoxy adhesive EP-170 manufactured by Cemedine Co., Ltd. was applied to the surface.
Coated by screen printing. After heating at 120 ° C. for 7 minutes after the application, two etched substrates were pressed with 4.5 μm of an aromatic polyamide film (trade name: Aramica) manufactured by Asahi Kasei Corporation. As a result, a substrate having four conductor layers was obtained. The obtained substrate was similarly punched with a die, but among the 500 obtained coils, 372 had the adhesive layer peeled off after punching.
When the thickness of 100 pieces was measured, the average was 289 μm.
In comparison with Example 1, the thickness was 105 μm thick, and about 1.
6 times. This is different from the first embodiment in that the magnet (magnetic flux density Br = 11000 Gauss) of the motor mounting this coil is used.
It was necessary to increase the distance between the s) and the yoke by 0.5 mm by about 0.1 mm, and the magnetic field intensity decreased by 22%, so that the torque constant also decreased by 22% to 37.5 gcm / A.

[0036]

COMPARATIVE EXAMPLE 2 A resist pattern is formed on a conductive substrate, for example, an aluminum foil, except where it becomes a conductor, and then electrolytic copper plating is performed so as to deposit a required amount of copper. As a result, the conductor pattern portion had a conductor thickness of 35 μm, and the conductor interval was 20 μm in the coil portion. Thereafter, 7 g of an epoxy adhesive EP-170 manufactured by Cemedine Co. was applied to the polished surface by screen printing. After heating at 120 ° C. for 7 minutes after application, a polyimide film (trade name: Kapton) 25 μm manufactured by Toray DuPont was pressed between them. The Kapton used has a tensile modulus of 300 kg / mm ² and a dielectric breakdown voltage of 280 KV / mm.

The press was initially heated at a rate of 2 ° C./min.
Pressing was performed at 0 kg / cm ² . 60 at 135 ° C
Pressing was continued until the substrate temperature reached 60 ° C. after the minute pressing.
The aluminum substrate was removed by etching with 8% hydrochloric acid for 30 minutes. The obtained substrate was punched into a coil shape for a brushless motor using a mold. Of the 500 coils obtained as a result, 345 in which the adhesive layer was peeled off after punching was used.
Was individual. Moreover, 20 pieces were randomly sampled, the cross section was cut, and the distance between the conductors sandwiching the film was measured. The result was 25.2 μm on average. As shown in FIG.
A 0.1 μm adhesive layer 3 on each side of a 5 μm film 4
Existed.

Further, 20 samples were sampled and 20 mm
As a result of measuring the displacement at the center when the center was bent 100 g at the center with two fulcrums as the fulcrum, the average was 4.2.
mm.

[0039]

According to the present invention, an insulating layer that directly joins a plurality of conductor wiring pattern layers to the conductor and fills the gap between the conductors;
A film layer to ensure insulation between layers and mechanical strength,
By comprising the film and the adhesive layer for directly bonding the conductor, it is possible to secure a thin insulating layer, stable insulating properties, and holding properties of the conductor pattern.

Therefore, when the coil is used for the actuator, the thrust and the torque can be greatly improved.

[0041]

[Brief description of the drawings]

[0042]

FIG. 1 is a schematic view showing a cross section of a printed coil of the present invention.

[0043]

FIG. 2 is a schematic view showing a cross section of a print coil according to the related art.

[0044]

FIG. 3 is a schematic view showing a cross section of a print coil according to another conventional technique.

[0045]

FIG. 4 is a diagram illustrating an example of a motor using a printed coil.

[0046]

FIG. 5 is a plan view showing an example of a print coil.

[0047]

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductor pattern 2 Varnish 3 Adhesive layer 4 Film 5 Rotor 6 Print coil 7 Yoke plate 8 Spiral coil 9 Through hole

Claims (6)

[Claims] A first insulating material having at least one layer of a conductive wiring pattern, wherein a first insulating material existing between the conductive wiring patterns is directly joined to a portion of the conductive wiring pattern and the first insulating material facing the insulating base material; An actuator print coil, comprising an insulating material and an insulating base material corresponding to the conductor wiring pattern in one or more layers, wherein the first insulating material forms at least half of the conductor thickness between conductors of the conductor wiring pattern. The printed coil for an actuator, wherein the second insulating material has a thickness of 1 to 20 μm. 2. The printed coil for an actuator according to claim 1, wherein the insulating base is in the form of a film and has a thickness of 20 μm or less. 3. The actuator print according to claim 2, wherein the insulating base material is in the form of a film, the tensile elastic modulus is 250 kg / mm ² or more, and the dielectric breakdown voltage is 200 KV / mm or more. coil. 4. The printed coil for an actuator according to claim 3, wherein the insulating base material contains an aromatic polyamide. 5. The printed coil for an actuator according to claim 1, wherein a joining surface of the conductor wiring pattern directly joined to the second insulating material is subjected to a physical polishing treatment. 6. A step of applying an insulating material to the substrate on which the conductor wiring pattern is formed, a step of polishing the surface on which the insulating material is applied, and partially removing the insulating material on the surface of the conductor.
Bonding the substrate on which the conductor wiring pattern is formed to an insulating film with an adhesive.