CN115398565A - Insulated wire and method for manufacturing same - Google Patents
Insulated wire and method for manufacturing same Download PDFInfo
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- CN115398565A CN115398565A CN202180027223.5A CN202180027223A CN115398565A CN 115398565 A CN115398565 A CN 115398565A CN 202180027223 A CN202180027223 A CN 202180027223A CN 115398565 A CN115398565 A CN 115398565A
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- conductor
- insulating layer
- insulated wire
- insulating
- covering
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
- H01B13/06—Insulating conductors or cables
- H01B13/16—Insulating conductors or cables by passing through or dipping in a liquid bath; by spraying
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B7/00—Insulated conductors or cables characterised by their form
- H01B7/02—Disposition of insulation
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F5/00—Coils
- H01F5/06—Insulation of windings
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- Manufacturing & Machinery (AREA)
- Power Engineering (AREA)
- Processes Specially Adapted For Manufacturing Cables (AREA)
- Insulated Conductors (AREA)
Abstract
The insulated wire includes: a linear conductor having a first surface, a second surface facing the first surface, a third surface, and a fourth surface facing the third surface; and an insulating layer covering the conductor, wherein the insulating layer has: a first insulating layer directly contacting the conductor; and one or more upper insulating layers covering the first insulating layer, the first insulating layer having a first covering portion covering the first surface, a second covering portion covering the second surface, a third covering portion covering the third surface, and a fourth covering portion covering the fourth surface, wherein in a cross section perpendicular to the longitudinal direction of the insulated wire, when a layer thickness of the first covering portion is represented by Ta, a layer thickness of the second covering portion is represented by Ta, a layer thickness of the third covering portion is represented by Tb, and a layer thickness of the fourth covering portion is represented by Tb, ratios represented by Ta/Ta and Tb/Tb are each 1.6 or less.
Description
Technical Field
The present disclosure relates to an insulated wire and a method of manufacturing an insulated wire. The present application claims priority from Japanese application No. 2020-073067, which was filed on behalf of the applicant on day 15/4 in 2020, and the entire contents of the disclosure in said Japanese application are incorporated herein by reference.
Background
Insulated electric wires including a linear conductor and an insulating layer covering the conductor are known. The insulated wire is suitable for use as, for example, a coil of a motor, a transformer, or the like. International publication No. 2013/073397 discloses that the adhesion between a conductor and an insulating layer is improved by suppressing unevenness in the thickness of the insulating layer in the insulated electric wire.
Documents of the prior art
Patent document
Patent document 1: international publication No. 2013/073397
Patent document 2: japanese patent laid-open No. 2008-097888
Disclosure of Invention
The insulated wire of the present disclosure includes: a linear conductor having a first surface, a second surface facing the first surface, a third surface, and a fourth surface facing the third surface; and an insulating layer covering the conductor, wherein the insulating layer has: a first insulating layer directly contacting the conductor; and one or more upper insulating layers covering the first insulating layer, the first insulating layer having a first covering portion covering the first surface, a second covering portion covering the second surface, a third covering portion covering the third surface, and a fourth covering portion covering the fourth surface, wherein in a cross section of the insulated wire perpendicular to the longitudinal direction, when a layer thickness of the first covering portion is represented by Ta, a layer thickness of the second covering portion is represented by Ta, a layer thickness of the third covering portion is represented by Tb, and a layer thickness of the fourth covering portion is represented by Tb, ratios represented by Ta/Ta and Tb/Tb are each 1.6 or less.
The method for manufacturing an insulated wire according to the present disclosure is a method for manufacturing an insulated wire including a linear conductor having a first surface, a second surface facing the first surface, a third surface, and a fourth surface facing the third surface, and an insulating layer covering the conductor, the method for manufacturing an insulated wire including: preparing the conductor and the insulating varnish; coating the conductor with the first insulating layer; and a step of laminating the upper insulating layer on the first insulating layer, the coating step including: applying the insulating varnish to the conductor; adjusting the thickness of the insulating varnish applied to the conductor; and a step of baking the insulating varnish to the conductor, wherein the step of adjusting the thickness is performed by allowing the conductor coated with the insulating varnish to pass through an opening of a coating die so that a distance between an inner wall of the opening and the conductor is 0.040mm or less.
Drawings
Fig. 1 is a perspective view showing a longitudinal direction of an insulated wire according to the present embodiment.
Fig. 2 is a diagram schematically illustrating a cross section perpendicular to the longitudinal direction of the insulated wire according to the present embodiment.
Fig. 3 is a process diagram of the method for manufacturing an insulated wire according to the present embodiment.
Detailed Description
[ problems to be solved by the present disclosure ]
With the demand for downsizing of coils, it is sometimes required to wind insulated wires around a small iron core at high density and high speed. In this case, it is necessary to further strengthen the adhesion force between the conductor and the insulating layer so that the insulating layer covering the outer peripheral surface of the conductor is maintained without being damaged even if a large stress is applied to the insulated wire at the time of winding. Therefore, in view of the recent strict requirements for performance, development of an insulated wire having further enhanced adhesion between a conductor and an insulating layer is strongly desired.
An object of the present disclosure is to provide an insulated wire having improved adhesion force between a conductor and an insulating layer, and a method for manufacturing the same.
[ Effect of the present disclosure ]
According to the present disclosure, an insulated wire in which the adhesion force between the conductor and the insulating layer is improved and a method for manufacturing the same can be provided.
[ description of embodiments of the present disclosure ]
The present inventors have made intensive studies to solve the problems, and as a result, the present disclosure has been completed. Specifically, attention is paid to suppressing variation in the layer thickness of the first insulating layer directly contacting the conductor in the insulating layer covering the linear conductor in the insulated electric wire. As a result, the present inventors have found that an insulated wire in which the thickness of the first insulating layer is uniform has improved adhesion force between a conductor and an insulating layer as compared with a conventional insulated wire, and have reached the present disclosure.
First, embodiments of the present disclosure are exemplified for explanation.
[1] An insulated wire according to an aspect of the present disclosure includes: a linear conductor having a first surface, a second surface facing the first surface, a third surface, and a fourth surface facing the third surface; and an insulating layer covering the conductor, wherein the insulating layer has: a first insulating layer directly contacting the conductor; and one or more upper insulating layers covering the first insulating layer, the first insulating layer having a first covering portion covering the first surface, a second covering portion covering the second surface, a third covering portion covering the third surface, and a fourth covering portion covering the fourth surface, wherein in a cross section perpendicular to the longitudinal direction of the insulated wire, when a layer thickness of the first covering portion is represented by Ta, a layer thickness of the second covering portion is represented by Ta, a layer thickness of the third covering portion is represented by Tb, and a layer thickness of the fourth covering portion is represented by Tb, ratios represented by Ta/Ta and Tb/Tb are each 1.6 or less. In the insulated wire having such a feature, since variation in the thickness of the first insulating layer is suppressed, the adhesion between the conductor and the insulating layer can be improved.
[2] Either one of the ratios represented by the Ta/Ta or Tb/Tb may be 1.4 or less. This improves the adhesion between the conductor and the insulating layer.
[3] The ratio represented by Ta/Ta and Tb/Tb may be 1.4 or less. This can further improve the adhesion force between the conductor and the insulating layer.
[4] The cross-sectional shape of the conductor in the cross section may be flat. Thus, the insulated wires can be wound around the core at high density.
[5] A method for manufacturing an insulated wire according to an aspect of the present disclosure is a method for manufacturing an insulated wire including a linear conductor having a first surface, a second surface facing the first surface, a third surface, and a fourth surface facing the third surface, and an insulating layer covering the conductor, the method for manufacturing the insulated wire including: preparing the conductor and the insulating varnish; coating the conductor with the first insulating layer; and a step of laminating the upper insulating layer on the first insulating layer, the coating step including: applying the insulating varnish to the conductor; adjusting the thickness of the insulating varnish applied to the conductor; and a step of baking the insulating varnish to the conductor, wherein the step of adjusting the thickness is performed by allowing the conductor coated with the insulating varnish to pass through an opening of a coating die so that a distance between an inner wall of the opening and the conductor is 0.040mm or less. In the method for manufacturing an insulated wire having such a feature, since the first insulating layer in which the variation in layer thickness is suppressed can be coated on the conductor, an insulated wire in which the adhesion force between the conductor and the insulating layer is improved can be manufactured.
[ details of embodiments of the present disclosure ]
Hereinafter, embodiments of the present disclosure (hereinafter, also referred to as "the present embodiments") will be described in further detail. In the drawings used in the description of the present embodiment, the same reference numerals are used for the same or corresponding portions. In the drawings, the scale of each component is appropriately adjusted to facilitate understanding of each component, and the scale of each component shown in the drawings does not necessarily coincide with the scale of the actual component.
In the present disclosure, the expression of the form "a to B" refers to the upper and lower limits of the range (i.e., a to B), and when a unit is not described in a but only B is described, the unit of a is the same as the unit of B.
[ insulated wire ]
Hereinafter, an insulated wire according to the present embodiment will be described with reference to fig. 1 and 2.
Fig. 1 is a perspective view showing a longitudinal direction of an insulated wire according to the present embodiment.
Fig. 2 is a diagram schematically illustrating a cross section perpendicular to the longitudinal direction of the insulated wire according to the present embodiment. As shown in fig. 1 and 2, the present embodiment is an insulated wire 1 including a linear conductor 11 and an insulating layer 20 covering the conductor 11. The insulating layer 20 has: a first insulating layer 21 directly contacting the conductor 11; and one or more upper insulating layers 22 disposed on the first insulating layer 21. In the description of the present embodiment, as shown in fig. 1 and 2, a case where the cross-sectional shape of the conductor 11 in the cross section of the insulated wire 1 is flat is exemplified.
In the insulated wire according to the present embodiment, the first insulating layer has a first covering portion, a second covering portion, a third covering portion, and a fourth covering portion as portions covering the two pairs of opposed surfaces of the conductor. The first insulating layer has first facing surfaces of a first covering part and a second covering part, and second facing surfaces of a third covering part and a fourth covering part as portions covering the two pairs of facing surfaces of the conductor. In the insulated wire, when the layer thickness of the first coating portion is represented by Ta, the layer thickness of the second coating portion is represented by Ta, the layer thickness of the third coating portion is represented by Tb, and the layer thickness of the fourth coating portion is represented by Tb in a cross section perpendicular to the longitudinal direction of the insulated wire, the ratio represented by Ta/Ta and Tb/Tb is 1.6 or less.
Either one of the ratios represented by Ta/Ta or Tb/Tb may be 1.4 or less. In the insulated wire 1 having such a feature, since variation in the thickness of the first insulating layer 21 is suppressed, the adhesion force between the conductor 11 and the insulating layer 20 can be improved.
The ratio represented by Ta/Ta and Tb/Tb may be 1.4 or less. The adhesion force between the conductor 11 and the insulating layer 20 can be further improved. The reason for the improvement of the adhesion force between the conductor 11 and the insulating layer 20 in the insulated wire 1 will be described later.
< conductor >
As described above, the insulated wire 1 of the present embodiment includes the linear conductor 11. The conductor 11 is an electrical conductor. As a material of the conductor 11, a metal having high electrical conductivity and high mechanical strength is preferable. Specific examples thereof include copper, copper alloy, aluminum alloy, nickel, silver, soft iron, steel, and stainless steel. The conductor 11 may be a wire rod formed by forming these metals into a wire shape, a coated wire formed by coating the surface of a wire rod with another metal, or a stranded wire formed by stranding a plurality of wire rods. Examples of the coated wire include, but are not limited to, a nickel-coated copper wire, a silver-coated aluminum wire, and a copper-coated steel wire.
The shape of the conductor 11 may be appropriately selected according to the use application, electrical characteristics, and the like of the insulated wire 1.
In the present embodiment, the cross-sectional shape of the conductor 11 is flat in order to wind the insulated wire 1 around the core at high density.
The diameter, the length of the outer periphery, and the like of the conductor 11 are not particularly limited, and may be appropriately selected according to the use application, the electrical characteristics, and the like of the insulated wire 1.
Here, in the present disclosure, "flat" as one of the sectional shapes of the conductor 11 includes rectangles and squares, and four corners including these rectangles and squares are chamfered or have a shape of a circular arc shape (R shape).
The lower limit of the sectional area of the conductor 11 may be 0.01mm 2 . The cross-sectional area of the conductor 11 is less than 0.01mm 2 In the case of (2), the ratio of the volume of the insulating layer 20 to the volume of the conductor 11 is increased, and the volume efficiency of the coil formed using the insulated wire 1 may be reduced. The upper limit value of the sectional area of the conductor 11 may be 20mm 2 . The cross-sectional area of the conductor 11 exceeds 20mm 2 In the case of (2), in order to sufficiently improve the insulation of the insulated wire 1, the insulating layer 20 needs to be thick, and as a result, the diameter of the insulated wire 1 becomes large, and it tends to be difficult to wind the insulated wire around the core at a high density.
The lower limit of the cross-sectional area of the conductor 11 may be 0.1mm 2 . The cross-sectional area of the conductor 11 is less than 0.1mm 2 In the case of (2), the conductor resistance at the time of energization is increased, and heat generation loss may occur. The upper limit of the cross-sectional area of the conductor 11 may be 10mm 2 . The cross-sectional area of the conductor 11 exceeds 10mm 2 In this case, the bending of the coil formed by using the insulated wire 1 may be difficult.
< insulating layer >
As described above, the insulated wire 1 of the present embodiment includes the insulating layer 20 covering the conductor 11. The insulating layer 20 has: a first insulating layer 21 directly contacting the conductor 11; and one or more upper insulating layers 22 disposed on the first insulating layer 21.
Examples of the resin constituting the insulating layer 20 include thermosetting resins such as polyvinyl formal resin, polyurethane resin, alkyl resin, epoxy resin, phenoxy resin, polyester imide resin, polyester amide imide resin, polyamide imide resin, and polyimide resin, and thermoplastic resins such as polyetherimide resin, polyether ether ketone resin, polyether sulfone resin, and polyimide resin. These resins are used alone or in combination of two or more.
May be a thermosetting polyimide resin. The strength and heat resistance of the insulating layer 20 can be improved.
The first insulating layer 21 and the upper insulating layer 22 constituting the insulating layer 20 may be formed by selecting the same resin from the various resins described above, or may be formed by selecting different resins from the various resins described above.
The lower limit of the thickness of the insulating layer 20 (the total thickness of the first insulating layer 21 and the upper insulating layer 22) may be 5 μm. If the thickness of the insulating layer 20 is less than 5 μm, the insulating layer 20 tends to be easily broken, and the insulation of the conductor 11 may become insufficient.
The upper limit of the thickness of the insulating layer 20 may be 200 μm. If the thickness of the insulating layer 20 exceeds 200 μm, the volume efficiency of a coil or the like formed using the insulated wire 1 tends to be low.
The thickness of the insulating layer 20 is an average value of the thicknesses of the insulating layers 20 coated on the two pairs of facing surfaces (upper surface, lower surface, left surface, and right surface) of the conductor 11. Specifically, the insulated wire 1 is cut on a plane perpendicular to the longitudinal direction thereof to form a cross section, and the cross section is polished to form a surface to be measured. Then, the measurement target surface was photographed by using a digital microscope VHX-7000 (manufactured by KEYENCE corporation), thereby obtaining an image. Finally, as the thickness of the insulating layer 20 covering the two pairs of facing surfaces of the conductor 11 in the image, for example, 1 point may be selected from each of the upper surface, the lower surface, the left surface, and the right surface of the conductor 11, and an average value may be calculated from values obtained by measuring the thicknesses of the insulating layers 20 at the total of 4 points, and the average value may be taken as the thickness of the insulating layer 20.
(first insulating layer)
The first insulating layer 21 is an insulating layer directly contacting the conductor 11. In the present disclosure, the first insulating layer 21 refers to an insulating layer formed by baking based on an insulating varnish applied in direct contact with the conductor 11 as described below. The first insulating layer 21 has a first coating portion, a second coating portion, a third coating portion, and a fourth coating portion as portions that coat the two pairs of facing surfaces of the conductor 11. The first insulating layer has first facing surfaces of a first covering part and a second covering part, and second facing surfaces of a third covering part and a fourth covering part as portions covering the two pairs of facing surfaces of the conductor.
Layer thickness (Ta, ta, tb, tb) of first insulating layer
In the present embodiment, in a cross section perpendicular to the longitudinal direction of the insulated wire 1, when the layer thickness of the first coating portion of the first insulating layer 21 is denoted by Ta, the layer thickness of the second coating portion of the first insulating layer 21 is denoted by Ta, the layer thickness of the third coating portion of the first insulating layer 21 is denoted by Tb, and the layer thickness of the fourth coating portion of the first insulating layer 21 is denoted by Tb, the ratios denoted by Ta/Ta and Tb/Tb are each 1.6 or less. For example, in fig. 2, ta represents the thickness of the first insulating layer 21 covering the lower surface of the conductor 11, ta represents the thickness of the first insulating layer 21 covering the upper surface of the conductor 11, tb represents the thickness of the first insulating layer 21 covering the left surface of the conductor 11, and Tb represents the thickness of the first insulating layer 21 covering the right surface of the conductor 11.
In the present disclosure, ta is larger than Ta or equal to Ta (layer thickness) (Ta ≧ Ta), and Tb is larger than Tb or equal to Tb (layer thickness) (Tb ≧ Tb). That is, of the two pairs of opposed surfaces (first opposed surface and second opposed surface), the first opposed surface has a thicker layer as the first coated portion and the second opposed surface has a thinner layer as the second coated portion. In the second facing surface, the side having the larger layer thickness is defined as a third covered portion, and the side having the smaller layer thickness is defined as a fourth covered portion.
In this case, in the present embodiment, the ratios represented by Ta/Ta and Tb/Tb are both 1.6 or less.
The ratios represented by the above Ta/Ta and Tb/Tb may be both 1.4 or less, or both 1.1 or less. Desirably, the ratios represented by Ta/Ta and Tb/Tb are each 1.0. In these cases, the adhesion force between the conductor and the insulating layer can be further improved.
The first insulating layer 21 in which the ratios represented by Ta/Ta and Tb/Tb are both 1.6 or less can be obtained, for example, by allowing the conductor 11 coated with the insulating varnish to pass through the opening of the coating die so that the distance between the inner wall of the opening of the coating die and the conductor becomes 0.040mm or less, as described later.
In the field of insulated wire technology, there has been no idea of suppressing variation in the layer thickness of an insulating layer (first insulating layer) directly contacting a conductor. On the other hand, in the case where the ratios represented by the Ta/Ta and the Tb/Tb of the first insulating layer 21 of the insulated wire 1 in the present disclosure are both 1.6 or less, the adhesion force between the conductor 11 and the insulating layer 20 is more excellent than that of the conventional insulated wire. The reason for this is not clear in detail, but it is considered as follows.
In the insulating layer (first insulating layer) directly contacting the conductor, for example, there may be a portion (hereinafter, also referred to as "thickened portion") having a thickness larger than the thickness of the first facing surface and the thickness of the second facing surface. In this case, the adhesion force with the conductor tends to decrease in the thickened portion. This is because, in the thickened portion, it is presumed that the heat input is insufficient when baking the insulating varnish, or the solvent of the insulating varnish is difficult to volatilize and dissipate, and therefore, there is a possibility that sufficient baking cannot be performed. Therefore, in order to obtain sufficient adhesion between the conductor and the insulating layer, it is assumed that it is important to make the thickened portion not exist in the first insulating layer 21 directly contacting the conductor 11.
As described above, it is considered that when the thickness variation of the first insulating layer 21 is suppressed so that the above-described thickened portion does not exist and the ratios indicated by Ta/Ta and Tb/Tb are both 1.6 or less, excellent adhesion force can be provided between the conductor 11 and the insulating layer 20.
Method for measuring layer thickness (Ta, ta, tb, tb) of first insulating layer
The layer thickness (Ta, tb) of the first insulating layer can be measured by the same method as the method for measuring the thickness of the insulating layer 20 described above. First, an image is obtained in the same manner as the method for measuring the thickness of the insulating layer 20. Next, the thickness of the first insulating layer 21, i.e., the thicknesses Ta, tb, and Tb of the first, second, third, and fourth coatings, at 4 points in total, can be determined by selecting 1 point from each of the upper, lower, left, and right surfaces of the conductor 11 in the image.
(Upper insulating layer)
The upper insulating layer 22 is one or more insulating layers disposed on the first insulating layer 21. The upper insulating layer 22 may be laminated on the first insulating layer 21 by a conventionally known method as described below. The specific number of the upper insulating layers 22 disposed on the first insulating layer 21 may be appropriately selected depending on the use application, electrical characteristics, and the like of the insulated wire 1, but generally 1 to 100 upper insulating layers 22 may be disposed on the first insulating layer 21.
The thickness of the upper insulating layer 22 can be determined as the difference between the thickness of the insulating layer 20 and the thickness of the first insulating layer 21 obtained by the above-described measurement method. When the insulated wire 1 is observed using a fluorescence microscope for measuring the thickness of the insulating layer 20, the interface between the upper insulating layer 22 and the first insulating layer 21 can be clearly defined in the cross section perpendicular to the longitudinal direction of the insulated wire 1. In addition, when the upper insulating layer 22 is a plurality of layers, the interface between the plurality of layers can also be clearly defined.
< adhesion force between conductor and insulating layer >
Here, in the insulated wire 1 of the present embodiment, the adhesion force between the conductor 11 and the insulating layer 20 can be evaluated by the following method. First, an insulated wire 1 is obtained by a manufacturing method described later. Next, two opposing cuts are cut out in the insulating layer 20 of the insulated wire 1 parallel to the longitudinal direction of the insulated wire 1 so as to reach the conductor 11 using a cutting blade. Here, the interval between the two incisions is set to 1.0mm.
Then, one end side in the longitudinal direction of the two slits was pulled up with tweezers, and the pulled-up portion was set at a predetermined position in a tensile testing machine (5 kg load cell, manufactured by shimadzu corporation). Then, the peelable portion was stretched at a stretching speed of 100 mm/min to determine peel (peel) strength. The peel strength (in N/mm) obtained in this way can be evaluated as the adhesion force between the conductor 11 and the insulating layer 20. As a result, the larger the value of the peel strength, the more excellent the adhesion force between the conductor 11 and the insulating layer 20 can be evaluated.
[ method for producing insulated wire ]
Hereinafter, a method for manufacturing an insulated wire according to the present embodiment will be described with reference to fig. 3.
For example, from the viewpoint of high-yield manufacturing, the insulated wire 1 of the present embodiment can be obtained by using the following method for manufacturing an insulated wire. That is, the method of manufacturing the insulated wire 1 according to the present embodiment is a method of manufacturing an insulated wire 1 including a linear conductor 11 and an insulating layer 20 covering the conductor 11, in which the insulating layer 20 includes: a first insulating layer 21 directly contacting the conductor 11; and one or more upper insulating layers 22 disposed on the first insulating layer 21. The method for manufacturing the insulated wire 1 includes: a step (first step) of preparing the conductor 11 and the insulating varnish; a step (second step) of coating the conductor 11 with the first insulating layer 21; and a step (third step) of laminating an upper insulating layer 22 on the first insulating layer 21.
The coating step (second step) includes: a step (a) of applying an insulating varnish to the conductor 11; a step (B) of adjusting the thickness of the insulating varnish applied to the conductor 11; and a step (C step) of baking the insulating varnish to the conductor 11. The step (B) of adjusting the thickness is performed by passing the conductor 11 coated with the insulating varnish through the opening of the coating die so that the distance between the inner wall of the opening and the conductor 11 becomes 0.040mm or less. In the method of manufacturing the insulated wire 1 having such a feature, the first insulating layer 21 in which the variation in layer thickness is suppressed can be coated on the conductor 11, and therefore, the insulated wire 1 in which the adhesion force between the conductor 11 and the insulating layer 20 is improved can be manufactured. Hereinafter, each step included in the method for manufacturing the insulated wire 1 according to the present embodiment will be described in detail.
< first Process step >
The first step is a step of preparing the conductor 11 and the insulating varnish (S11). The conductor 11 can be prepared by, for example, obtaining a commercially available product. Alternatively, the conductor 11 may be prepared by casting the metal, drawing the metal into a wire, and softening the wire. The insulating varnish may be prepared by diluting the above resin or a resin precursor of the resin, which is a material of the insulating layer 20, with a solvent. The concentration of the resin solid content in the insulating varnish may be a conventional concentration known for the purpose of producing such an insulated wire.
The lower limit of the resin solid content concentration in the insulating varnish may be 15 mass%. If the resin solid content is less than 15 mass%, the thickness of each layer after baking may be reduced, and productivity may be reduced.
The upper limit of the resin solid content concentration in the insulating varnish may be 50 mass%. When the resin solid content concentration exceeds 50 mass%, the insulating varnish after coating becomes thick, and the coating film may foam during baking.
When the insulating varnish contains a resin precursor, the resin solid content concentration refers to the concentration of the resin precursor.
Here, the insulating varnish may contain a curing agent, a filler, various additives, and the like in addition to the above-described solvent, resin, or resin precursor of the resin.
As the solvent, a known organic solvent can be used. Specifically, there may be mentioned: polar organic solvents such as N-methyl-2-pyrrolidone, N-dimethylacetamide, N-dimethylformamide, dimethyl sulfoxide, tetramethylurea, hexaethylphosphoric triamide, and γ -butyrolactone; ketone organic solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester-based organic solvents such as methyl acetate, ethyl acetate, butyl acetate, and diethyl oxalate; ether-based organic solvents such as diethyl ether, ethylene glycol dimethyl ether, diethylene glycol monomethyl ether, ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol dimethyl ether, and tetrahydrofuran; hydrocarbon-based organic solvents such as hexane, heptane, benzene, toluene, and xylene; halogen-based organic solvents such as methylene chloride and chlorobenzene; phenol organic solvents such as cresol and chlorophenol; amine-based organic solvents such as pyridine. These organic solvents may be used alone or in combination of two or more.
As the curing agent, a curing agent having a function of curing the resin in the step B described later or a function of accelerating polymerization of the resin precursor can be used. Specific examples thereof include alicyclic acid anhydrides such as methyltetrahydrophthalic anhydride, aliphatic acid anhydrides, aromatic acid anhydride imidazole, triethylamine, titanium compounds, isocyanate compounds, blocked isocyanate, urea, melamine compounds, and acetylene derivatives. These curing agents are appropriately selected depending on the kind of the resin or the resin precursor in the insulating varnish.
Examples of the titanium-based compound include tetrapropyl titanate, tetraisopropyl titanate, tetramethyl titanate, tetrabutyl titanate, and tetrahexyl titanate. Examples of the isocyanate compound include: aromatic diisocyanates such as Toluene Diisocyanate (TDI), diphenylmethane diisocyanate (MDI), p-phenylene diisocyanate, and naphthalene diisocyanate; aliphatic diisocyanates having 3 to 12 carbon atoms such as Hexamethylene Diisocyanate (HDI), 2, 4-trimethylhexane diisocyanate, lysine diisocyanate, etc.; alicyclic isocyanates having 5 to 18 carbon atoms such as 1, 4-Cyclohexane Diisocyanate (CDI), isophorone diisocyanate (IPDI), 4 '-dicyclohexylmethane diisocyanate (hydrogenated MDI), methylcyclohexane diisocyanate, isopropylidene dicyclohexyl-4, 4' -diisocyanate, 1, 3-diisocyanatomethylcyclohexane (hydrogenated XDI), hydrogenated TDI, 2, 5-bis (isocyanatomethyl) -bicyclo [2, 1] heptane, 2, 6-bis (isocyanatomethyl) -bicyclo [2, 1] heptane and the like; aliphatic diisocyanates having an aromatic ring such as Xylylene Diisocyanate (XDI) and tetramethylxylylene diisocyanate (TMXDI); modified products thereof, and the like.
Examples of the blocked isocyanate include diphenylmethane-4, 4 '-diisocyanate (MDI), diphenylmethane-3, 3' -diisocyanate, diphenylmethane-3, 4 '-diisocyanate, diphenyl ether-4, 4' -diisocyanate, benzophenone-4, 4 '-diisocyanate, diphenylsulfone-4, 4' -diisocyanate, toluene-2, 4-diisocyanate, toluene-2, 6-diisocyanate, naphthalene-1, 5-diisocyanate, m-xylylene diisocyanate, and p-xylylene diisocyanate. Examples of the melamine compound include methylated melamine, butylated melamine, hydroxymethylated melamine, and hydroxybutylated melamine. Examples of the acetylene derivative include ethynylaniline and ethynylphthalic anhydride.
< second step >
The second step is a step of coating the conductor 11 with the first insulating layer 21 (S12). The second step includes: a step (a) of applying an insulating varnish to the conductor 11; a step (B) of adjusting the thickness of the insulating varnish applied to the conductor 11; and a step (step C) of baking the insulating varnish to the conductor 11.
(Process A)
The step a is a step of applying the insulating varnish prepared in the first step to the conductor 11.
(step B)
The step B is a step of adjusting the thickness of the insulating varnish applied to the conductor 11. The step B is performed by passing the conductor 11 coated with the insulating varnish through the opening of the coating die so that the distance between the inner wall of the opening and the conductor 11 becomes 0.040mm or less.
That is, in the step B, the thickness of the insulating varnish applied to the conductor 11 is adjusted by using an application die having an opening.
(step C)
The step C is a step of baking the insulating varnish to the conductor 11. In the step C, the first insulating layer 21 directly contacting the conductor 11 is formed by baking. Specifically, the conductor 11 coated with the insulating varnish through the steps a and B is placed in a baking oven, and the insulating varnish is baked until the conductor 11. As a result, the resin is solidified by vaporization of the solvent in the insulating varnish, and the first insulating layer 21 directly contacting the conductor 11 can be formed. In this case, since the insulating varnish is applied to the conductor 11 in a uniform thickness through the step a, the first insulating layer 21 formed in direct contact with the conductor 11 also has a uniform layer thickness, and variation in the layer thickness can be suppressed.
The baking temperature and time of the insulating varnish in the baking oven may be appropriately selected from temperature conditions and time conditions known in the case of the purpose of manufacturing such an insulated wire, depending on the kind of resin in the insulating varnish.
< third Process step >
The third step is a step of laminating the upper insulating layer 22 on the first insulating layer 21 (S13). In the third step, the application of the insulating varnish and the baking of the insulating varnish are repeated until the insulating layer 20 has a predetermined thickness, whereby one or more upper insulating layers 22 are stacked on the first insulating layer 21. The insulating varnish can be applied by a conventionally known method and can be baked. By performing the application of the insulating varnish and the baking of the insulating varnish in the above-described steps a and B, a desired number of upper insulating layers 22 can be stacked on the first insulating layer 21.
In the present disclosure, an insulating layer obtained by performing the application of the insulating varnish and the baking of the insulating varnish once is referred to as a "one-layer" insulating layer, and an insulating layer obtained by performing the application of the insulating varnish and the baking of the insulating varnish a plurality of times is referred to as a "multi-layer" insulating layer.
In the present disclosure, an insulating layer obtained by coating an insulating varnish once and baking once is referred to as "one-layer" insulating layer. An insulating layer obtained by repeating a process of applying an insulating varnish once and baking once a plurality of times is referred to as a "multilayer" insulating layer.
< effect >
In summary, it is possible to manufacture an insulated wire 1 including a linear conductor 11 and an insulating layer 20 covering the conductor 11, wherein the insulating layer 20 has: a first insulating layer 21 directly contacting the conductor 11; and one or more upper insulating layers 22 disposed on the first insulating layer 21. In the insulated wire 1 manufactured by the above-described manufacturing method, variation in the layer thickness of the first insulating layer 21 is suppressed.
In the insulated wire 1, the first insulating layer 21 has a first covering portion, a second covering portion, a third covering portion, and a fourth covering portion as portions covering the two pairs of opposed surfaces of the conductor 11. The first insulating layer 21 has first facing surfaces of a first covering part and a second covering part, and second facing surfaces of a third covering part and a fourth covering part as portions covering the two pairs of facing surfaces of the conductor. In a cross section perpendicular to the longitudinal direction of the insulated wire 1, when the layer thickness of the first coating portion is represented by Ta, the layer thickness of the second coating portion is represented by Ta, the layer thickness of the third coating portion is represented by Tb, and the layer thickness of the fourth coating portion is represented by Tb, the ratios represented by Ta/Ta and Tb/Tb are each 1.6 or less. This can provide the insulated wire 1 in which the adhesion force between the conductor 11 and the insulating layer 20 is improved.
Examples
The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited thereto.
[ measurement evaluation method ]
First, the measurement method and the evaluation method performed in the present example will be described.
< measurement of layer thickness of first insulating layer (Ta, ta, tb, tb) >)
The thicknesses of the first, second, third, and fourth covers of the first insulating layer were measured according to the above-described method for measuring the thicknesses of the first insulating layer layers (Ta, tb), and Tb, and values (in μm) of Ta and Ta, and Tb, respectively, were obtained.
< measurement of adhesion force between conductor and insulating layer and evaluation thereof >
The adhesion force between the conductor and the insulating layer was determined by the above-described method for measuring the adhesion force between the conductor and the insulating layer. Next, the adhesion force was evaluated based on the following criteria.
A: the peel strength is 1.0N/mm or more.
B: the peel strength is 0.5N/mm or more and less than 1.0N/mm.
C: the peel strength value is less than 0.5N/mm.
< measurement of proportion of unevenness in thickness of insulating layer and evaluation thereof >
First, each sample (insulated wire) described later was cut at 50cm intervals in the longitudinal direction on a plane perpendicular to the longitudinal direction, and 30 cross sections were obtained. Further, 4 points (1 point on each of the upper surface, the lower surface, the left surface, and the right surface) were selected at equal intervals on the outer peripheral surface of the conductor appearing on each cross section, and the layer thickness of the insulating layer and the average layer thickness thereof at the 4 points (4 points × 30 cross section =120 points average layer thickness) were obtained. Next, the average layer thickness is substituted into the following equation, and the ratio of the thickness unevenness of the insulating layer is obtained. In the following equations, σ represents a standard deviation. In the following equation, even if the average layer thickness is about the same, when the value of the deviation (4 σ) is large, the variation in the layer thickness is large.
Unevenness ratio (%) = (4 σ/average film thickness) × 100.
Next, the proportion of variation in the thickness of the insulating layer of each sample obtained based on the above equation was evaluated based on the following criteria. When the unevenness ratio exceeds 20%, the uniformity of the layer thickness of the insulating layer is low, and the adhesion force between the conductor and the insulating layer is considered to be insufficient.
OK: the proportion of unevenness in the insulating layer is 20% or less.
NG: the unevenness ratio of the insulating layer exceeds 20%.
[ production of insulated electric wire ]
< sample No. 1 >
The insulated wire of the present disclosure was manufactured by trial production according to the following procedure.
(first step)
First, a polyamic acid (polyamide precursor) having a weight-average molecular weight of 37500 was diluted with N-methyl-2-pyrrolidone (solvent), thereby preparing insulationAnd (3) varnish. In the insulating varnish, the content of the polyamic acid in the solvent is the same as that in the conventional one. Further, by casting, drawing and softening copper, a shape having a cross section formed by cutting on a plane perpendicular to the longitudinal direction and having a flat shape (cross section area: 5 mm) as shown in FIG. 2 was produced 2 ) The linear conductor 11.
(second Process)
Next, the conductor 11 is immersed in the insulating varnish to apply the insulating varnish to the conductor 11 (step a), and the conductor 11 coated with the insulating varnish is passed through an opening of a coating die having a shape similar to the cross-sectional shape of the conductor 11 (step B). At this time, the maximum distance between the conductor 11 and the inner wall of the opening of the coating die was 0.027mm. Further, the conductor coated with the insulating varnish through the steps a and B is subjected to baking treatment in a baking oven (step C). The baking temperature of the insulating varnish in the baking furnace is 450 ℃, and the baking time is 30 seconds. Thereby forming a first insulating layer 21 in direct contact with the conductor 11.
(third step)
Next, the application of the insulating varnish and the baking of the insulating varnish described above are repeated on the first insulating layer 21, whereby the upper insulating layer 22 is laminated on the first insulating layer 21. Specifically, the insulating varnish is applied to the first insulating layer 21, and the first layer of the upper insulating layer 22 is formed on the first insulating layer 21 by passing the insulating varnish through an opening of a coating die having a shape similar to the cross-sectional shape of the conductor 11. Next, the insulating varnish is applied to the first layer of the upper insulating layer 22, and the baking treatment is further performed, thereby forming a second layer of the upper insulating layer 22, and this operation is repeated a plurality of times. As described above, the insulated wire 1 was obtained by forming the insulating layer 20 having 25 layers in total of the first insulating layer 21 and the upper insulating layer 22 on the conductor 11.
< sample 2 to sample 4 >
Insulated wires were produced in the same manner as in sample 1, except that the conductor was produced so that the maximum distance between the conductor and the inner wall of the opening of the coating die when the conductor passed through the opening of the coating die was as shown in table 1.
[ evaluation of insulated electric wire ]
For the insulated wires of samples 1 to 4, ratios represented by Ta/Ta and Tb/Tb obtained from the layer thicknesses (Ta, tb) of the first insulating layer 21, adhesion force between the conductor and the insulating layer, and a ratio of variation in the thickness of the insulating layer 20 were obtained. The results are shown in Table 1. Table 1 also shows the maximum distance between the conductor and the inner wall of the opening of the coating die when the conductor is passed through the opening of the coating die in step a in the second step. Samples 1 to 3 are insulated wires of examples, and sample 4 is an insulated wire of a comparative example.
[ Table 1]
< investigation >
In samples 1 to 3, the ratios represented by Ta/Ta and Tb/Tb are all 1.6 or less. In this case, samples 1 to 3 are superior in the adhesion force between the conductor and the insulating layer to sample 4 in which any of the ratios represented by Ta/Ta and Tb/Tb exceeds 1.6. All of samples 1 to 4 showed OK evaluation (20% or less) in the ratio of variation in the thickness of the insulating layer.
The embodiments and examples disclosed herein are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the embodiments and examples described but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.
Description of the reference numerals
1: insulated wire
11: conductor for electric device
20: insulating layer
21: a first insulating layer
22: upper insulating layer
Ta: thickness of the first coating part
ta: thickness of the second coating part
Tb: thickness of the third coating portion
tb: the thickness of the fourth coating portion.
Claims (5)
1. An insulated wire comprising: a linear conductor having a first surface, a second surface facing the first surface, a third surface, and a fourth surface facing the third surface; and an insulating layer covering the conductor, wherein,
the insulating layer has: a first insulating layer directly contacting the conductor; and one or more upper insulating layers covering the first insulating layer,
the first insulating layer has a first coating portion covering the first surface, a second coating portion covering the second surface, a third coating portion covering the third surface, and a fourth coating portion covering the fourth surface,
in a cross section of the insulated wire perpendicular to the longitudinal direction, when the layer thickness of the first coating portion is represented by Ta, the layer thickness of the second coating portion is represented by Ta, the layer thickness of the third coating portion is represented by Tb, and the layer thickness of the fourth coating portion is represented by Tb, the ratios represented by Ta/Ta and Tb/Tb are each 1.6 or less.
2. The insulated wire according to claim 1,
either one of the ratios represented by the Ta/Ta or Tb/Tb is 1.4 or less.
3. The insulated wire according to claim 1,
the ratio represented by the Ta/Ta and Tb/Tb is 1.4 or less.
4. The insulated electric wire according to any one of claims 1 to 3,
the cross-sectional shape of the conductor in the cross-section is flat.
5. A method of manufacturing an insulated wire, the insulated wire comprising: a linear conductor having a first surface, a second surface facing the first surface, a third surface, and a fourth surface facing the third surface; and an insulating layer covering the conductor,
the method for manufacturing the insulated wire comprises the following steps:
a step of preparing the conductor and the insulating varnish;
coating the conductor with the first insulating layer; and
a step of laminating the upper insulating layer on the first insulating layer,
the coating step includes:
applying the insulating varnish to the conductor;
adjusting the thickness of the insulating varnish applied to the conductor; and
a step of baking the insulating varnish to the conductor,
the step of adjusting the thickness is performed by passing the conductor coated with the insulating varnish through an opening of a coating die so that a distance between an inner wall of the opening and the conductor is 0.040mm or less.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2020073067 | 2020-04-15 | ||
| JP2020-073067 | 2020-04-15 | ||
| PCT/JP2021/010963 WO2021210336A1 (en) | 2020-04-15 | 2021-03-18 | Insulated wire and method for manufacturing same |
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| Publication Number | Publication Date |
|---|---|
| CN115398565A true CN115398565A (en) | 2022-11-25 |
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| CN202180027223.5A Pending CN115398565A (en) | 2020-04-15 | 2021-03-18 | Insulated wire and method for manufacturing same |
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| JP (1) | JPWO2021210336A1 (en) |
| CN (1) | CN115398565A (en) |
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| JP5561830B2 (en) * | 2010-08-25 | 2014-07-30 | 住友電工ウインテック株式会社 | Coating die and method for manufacturing insulated wire |
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2021
- 2021-03-18 JP JP2022515260A patent/JPWO2021210336A1/ja active Pending
- 2021-03-18 WO PCT/JP2021/010963 patent/WO2021210336A1/en active Application Filing
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| JPWO2021210336A1 (en) | 2021-10-21 |
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