Tape winding insulation electric wire and coil

Abstract

To provide a tape winding insulation electric wire and a coil, capable of equalizing or increasing an insulation breakdown voltage even if a diameter of an insulation electric wire is fined by reducing a thickness of an insulation coating.SOLUTION: An insulation electric wire 10 has a conductor 1 and an insulation coating 2 provided to an outer periphery of the conductor 1, and the insulation coating 2 is constructed by a plurality of insulation layers (2a, 2b, 2c,...) overlapped and wound by two to five insulation tapes (11, 12, 13,...). In the case where an individual insulation layer obtained by being overlapped and wound by each insulation tape is a two-layer or a three-layer, a sum of winding numbers of each insulation layer is a sum obtained by adding one to a sum of an integral part of the winding number of each insulation layer or less. In the case where each insulation layer obtained by being overlapped and wound by each insulation tape is a four-layer or a five-layer, a sum of the number of winding of each insulation layer is a total number obtained by adding two to the sum of the integral part of the winding number of each insulation layer or less.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a tape-wound insulated wire and a coil used for a coil of an electronic component such as a power transformer, and more specifically, even if the thickness of the insulating coating is the same, the breakdown voltage can be made equal to or higher, or even if the thickness of the insulating coating is reduced to make the insulated wire thinner, the breakdown voltage can be made equal to or higher. The present invention relates to a tape-wound insulated wire and a coil formed of the tape-wound insulated wire.

Background Art

[0002] In electronic components such as transformers, inductors, and choke coils, in order to increase the occupation ratio, a triple-insulated wire that is reinforced insulation in safety standards such as IEC may be used (for example, Patent Document 1).

[0003] Patent Document 1 provides a multi-layer insulated wire in which the insulating layer is formed of three extruded coating layers, and even if the thickness of the insulating layer is reduced, the solderability, heat resistance, interlayer peeling property, and electrical insulation property satisfy the IEC standards. Since the first insulating layer of this multi-layer insulated wire is formed of a polyamide resin having high mechanical strength and softening temperature, the phenomenon of collapse of the insulating layer caused by the winding tension during coil processing or the conductor heat generation during coil use does not spread to the conductor surface. Therefore, even if the total thickness of the three extruded coating layers is 100 μm or less, when used as a coil winding, the occupation ratio of the coil can be increased.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, there has been a demand for higher efficiency and miniaturization through further improvement of the occupation ratio of the coil winding of transformers. However, for the conventional three-layer extrusion coating layer described above, the limit of the coating thickness of one layer is about 30 μm, and it has been difficult to reduce the coating thickness to increase the occupation ratio. On the other hand, tape-wound insulation coating with an insulating tape instead of the extrusion coating layer has also been carried out, but due to the coating strength and thickness depending on the tape material, the limit of the tape thickness is about 10 μm. However, with a thin tape, the insulation performance could not be sufficiently satisfied. In such conventional insulated wires for coil windings, it has been difficult to reduce the thickness while ensuring a high breakdown voltage, and the miniaturization of the coil with an increased occupation ratio of the coil has not been fully realized.

[0006] The present invention has been made to solve the above problems, and an object thereof is to provide a tape-wound insulated wire capable of making the breakdown voltage equal to or higher even when the thickness of the insulation coating is the same, or capable of making the breakdown voltage equal to or higher even when the thickness of the insulation coating is reduced to make the insulated wire thinner, and a coil formed of the tape-wound insulated wire.

Means for Solving the Problems

[0007] (1) The tape-wound insulated wire according to the present invention is an insulated wire having a conductor and an insulation coating on the outer periphery of the conductor, and the insulation coating is composed of a plurality of insulation layers wound around with two to five insulating tapes. When the insulation coating is composed of two or three individual insulation layers wound around with each of the insulating tapes, the total number of winding turns of the individual insulation layers is less than or equal to the total of the integer parts of the winding turns of the individual insulation layers plus 1, or when the individual insulation layers wound around with each of the insulating tapes are four or five layers, the total number of winding turns of the individual insulation layers is less than or equal to the total of the integer parts of the winding turns of the individual insulation layers plus 2, and in any case where the individual insulation layers are two to five layers, the integer part of the number of winding turns is in the range of 1 to 4. This is a feature.

[0008] According to the present invention, an insulating coating composed of a plurality of insulating layers wound around the outer periphery of a conductor with two to five insulating tapes, and when the number of layers of each insulating layer is two or three, the total number of turns of each insulating layer is less than or equal to the total of the integer parts (in the range of 1 to 4) of the number of turns of each insulating layer plus one, and when the number of layers of each insulating layer is four or five, the total is less than or equal to the total of the integer parts (in the range of 1 to 4) of the number of turns of each insulating layer plus two. Therefore, the sum of the fractional parts that are the fractional parts of the integer parts of the circumferential overlaps when winding with individual insulating tapes can be 1.0 or less or 2.0 or less. By doing so, the total thickness of the insulating coating can be reduced, and the obtained insulated wire can be made thinner. As a result, the space factor when manufacturing a coil can be improved.

[0009] Also, when the sum of the above-mentioned fractional parts is 1 or less or 2 or less, the number of turns of the integer part of the circumferential overlap when winding with individual insulating tapes can be sufficiently ensured. As a result, even if the thickness of the insulating coating is the same as that of a conventional insulated wire, the dielectric breakdown voltage can be made equal to or higher, or even if the thickness of the insulating coating is reduced and the insulated wire is made thinner, the dielectric breakdown voltage can be made equal to or higher. In addition, although it is advantageous for thinning when the fractional part is 1.0 or less or 2.0 or less, from the viewpoint of the substantial number of turns (hereinafter referred to as "minimum number of turns") consisting of the sum of the integer parts, the minimum number of turns can be increased by one or two, and the dielectric breakdown voltage can be increased. Since the dielectric breakdown voltage can be increased, if the dielectric breakdown voltage is at an equivalent level and sufficient, the insulating coating can be made thinner to contribute to the thinning of the insulated wire and the improvement of the space factor of the coil.

[0010] With such a tape-wound insulated wire, the dielectric breakdown voltage can be made equal to or improved, it is flexible, has excellent coil winding linearity, can increase the space factor and miniaturize the coil. Also, since the insulating coating can be made thinner, the thermal resistance of the insulated wire can be reduced, the heat dissipation performance can be improved, and the temperature of the insulated wire can be lowered.

[0011] (2) In the tape-wound insulated wire according to the present invention of (1) described above, when the insulating coatings are individual insulating layers wound one over another with each of the insulating tapes, and the number of layers of the insulating coatings is two or three, if the number of turns with the first insulating tape is represented as s.α multiple winding, the number of turns with the second insulating tape is represented as t.β multiple winding, and the number of turns with the third insulating tape is represented as u.γ multiple winding, then the sum of the integer parts is s + t when the number of insulating layers is two, and s + t + u when the number of insulating layers is three; the sum of the fractional parts is α + β when the number of insulating layers is two, and α + β + γ when the number of insulating layers is three, and the sum of the fractional parts is 1.0 or less. In this case, when the number of individual insulating layers is two, the third insulating tape described above is not used.

[0012] (3) In the tape-wound insulated wire according to the present invention of (2) described above, when there are two insulating tapes, the sum of the integer parts is from 2 to 8, the sum of the fractional parts is 1.0 or less, and the total sum is from 2.0 to 9.0; when there are three insulating tapes, the sum of the integer parts is from 3 to 12, the sum of the fractional parts is 1.0 or less, and the total sum is from 3.0 to 13.0.

[0013] (4) In the tape-wound insulated wire according to the present invention of (1) described above, when the insulating coatings are individual insulating layers wound one over another with each of the insulating tapes, and the number of layers of the insulating coatings is four or five, if the number of turns with the first insulating tape is represented as s.α multiple winding, the number of turns with the second insulating tape is represented as t.β multiple winding, the number of turns with the third insulating tape is represented as u.γ multiple winding, the number of turns with the fourth insulating tape is represented as v.δ multiple winding, and the number of turns with the fifth insulating tape is represented as w.ε multiple winding, then the sum of the integer parts is s + t + u + v when the number of insulating layers is four, and s + t + u + v + w when the number of insulating layers is five; the sum of the fractional parts is α + β + γ + δ when the number of insulating layers is four, and α + β + γ + δ + ε when the number of insulating layers is five, and the sum of the fractional parts is 2.0 or less. In this case, when the number of individual insulating layers is four, the fifth insulating tape described above is not used.

[0014] (5) In the tape-wound insulated wire according to the present invention described above in (4), the sum of the integer parts is 4 to 16, the sum of the decimal parts is 2.0 or less, the total sum is 4.0 to 18.0, and when there are 5 insulating tapes, the sum of the integer parts is 5 to 20, the sum of the decimal parts is 2.0 or less, and the total sum is 5.0 to 22.0.

[0015] (6) In the tape-wound insulated wire according to the present invention described above in (1) to (5), any one or two or more of the two to five insulating tapes may be provided with an adhesive layer.

[0016] (7) In the tape-wound insulated wire according to the present invention described above in (1) to (5), it is preferable that the insulating tape wound last among the plurality of insulating tapes is provided with a fusion layer on the outward-facing surface.

[0017] (8) The coil according to the present invention is characterized in that it is obtained by winding the tape-wound insulated wire according to the present invention described above in (1) to (5).

[0018] (9) The coil according to the present invention is characterized in that it is obtained by winding the tape-wound insulated wire according to the present invention described above in (6).

[0019] (10) The coil according to the present invention is characterized in that it is obtained by winding the tape-wound insulated wire according to the present invention described above in (7).

Advantages of the Invention

[0020] According to the tape-wound insulated wire of the present invention, the total thickness of the insulation coating can be reduced, and the obtained insulated wire can be made thinner. As a result, the space factor when manufacturing a coil can be improved. Further, even if the thickness of the insulation coating is the same, the breakdown voltage can be made equal to or higher, or even if the thickness of the insulation coating is reduced and the insulated wire is made thinner, the breakdown voltage can be made equal to or higher. As a result, the breakdown voltage can be made equal to or improved, the wire is flexible, has excellent coil winding linearity, and the space factor can be increased to miniaturize the coil. Also, since the insulation coating can be made thinner, the thermal resistance of the insulated wire is reduced, the heat dissipation property is increased, and the temperature of the insulated wire can be lowered.

[0021] According to the coil of the present invention, since it is wound with the above-described tape-wound insulated wire, it is possible to obtain a small coil with an equivalent or improved breakdown voltage, high productivity, and a high space factor.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0023] Hereinafter, the tape-wound insulated wire and coil according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to the illustrated embodiments.

[0024] [Tape-Wound Insulated Wire] The tape-wound insulated wire 10 according to the present invention (hereinafter sometimes simply referred to as "insulated wire 10") is an insulated wire 10 having a conductor 1 and an insulating coating 2 on the outer periphery of the conductor 1. As shown in FIGS. 1 to 3, the insulating coating 2 is composed of a plurality of insulating layers (2a, 2b, 2c, 2d, 2e) wound around each other with two to five insulating tapes (11, 12, 13, 14, 15). In this insulated wire 10, when each of the insulating layers wound with each insulating tape is two or three layers, the total number of turns of each insulating layer is less than or equal to the total number obtained by adding 1 to the sum of the integer parts of the number of turns of each insulating layer. Or, (2) when each of the insulating layers wound with each insulating tape is four or five layers, the total number of turns of each insulating layer is less than or equal to the total number obtained by adding 2 to the sum of the integer parts of the number of turns of each insulating layer. In any case where each insulating layer is two to five layers, the integer part of the number of turns is in the range of 1 to 4, which is a characteristic.

[0025] According to such a tape-wound insulated wire 10, the total thickness of the insulation coating 2 can be reduced, and the obtained insulated wire 10 can be made thinner. As a result, the space factor when manufacturing a coil can be improved. Also, even if the thickness of the insulation coating 2 is the same, the breakdown voltage can be made equal to or higher, or even if the thickness of the insulation coating 2 is reduced and the insulated wire 10 is made thinner, the breakdown voltage can be made equal to or higher. As a result, the breakdown voltage can be made equal to or improved, it is flexible, has excellent coil winding linearity, and the space factor can be increased to miniaturize the coil. Also, since the insulation coating 2 can be made thinner, the thermal resistance of the insulated wire is reduced, the heat dissipation property is increased, and the temperature of the insulated wire 10 can be lowered.

[0026] Hereinafter, each component will be described.

[0027] <Conductor> The conductor 1 is not particularly limited as long as it is applied as the central conductor of the insulated wire 10, particularly the insulated wire 10 for a coil, as shown in FIGS. 1 to 3, and any type of conductor may be used regardless of the material or the stranded configuration. For example, it may be composed of a single strand extending in the longitudinal direction, may be composed of a plurality of strands twisted together, or may be configured as a litz wire. The strand is not particularly limited as long as it is a highly conductive metal, but examples thereof preferably include highly conductive metal conductors such as copper wire, copper alloy wire, aluminum wire, aluminum alloy wire, copper-aluminum composite wire, or those having a plating layer on their surfaces. From the viewpoint of a coil, copper wire and copper alloy wire are particularly preferable. As the plating layer, a solder plating layer, a tin plating layer, a gold plating layer, a silver plating layer, a nickel plating layer, etc. are preferable. Further, the "conductor" and the "strand" also include those covered with an enamel layer or the like for insulation and oxidation prevention, etc., within the meaning of the conductor and the strand referred to in the present invention. The cross-sectional shape of the strand is not particularly limited, but it may be a wire having a circular or substantially circular cross-sectional shape, or may be a rectangular shape.

[0028] The cross-sectional shape of the conductor 1 is not particularly limited, and it may be circular (including elliptical) or rectangular or the like. It is desirable that the cross-sectional size of the conductor 1 be as large as possible so that the electrical resistance (AC resistance, conductor resistance) is small for favorable use as a coil. For example, the outer diameter of the circular strand can be about 0.05 to 5 mm. Also, in the case of a rectangular strand, the short side can be about 0.3 to 2 mm and the long side can be about 0.5 to 5 mm. These cross-sectional sizes of the conductor 1 are appropriately selected according to the application where the coil is used. However, the smaller the cross-sectional size, the higher the need to improve the adhesion and positioning accuracy of the insulation coating 2 described later.

[0029] <Insulation coating> The insulation coating 2 is formed by winding two to five insulation tapes in layers, and is composed of a plurality of insulation layers (two to five insulation layers) corresponding to the respective insulation tapes. Specifically, as shown in FIGS. 1 to 3, the insulation coating 2 is composed of two insulation layers (2a, 2b) wound around the outer periphery of the conductor 1 with two insulation tapes (11, 12), three insulation layers (2a, 2b, 2c) wound with three insulation tapes (11, 12, 13), four insulation layers (2a, 2b, 2c, 2d) wound with four insulation tapes (11, 12, 13, 14), or five insulation layers (2a, 2b, 2c, 2d, 2e) wound with five insulation tapes (11, 12, 13, 14, 15). The insulation coating 2 needs to have a thickness that ensures a specified dielectric breakdown voltage, but it is desirable to make it as thin as possible as long as the specified dielectric breakdown voltage can be ensured. If the insulation coating 2 can be made thin, there are advantages that the insulated wire 10 can be made thinner and the space factor of the coil can be increased. The present invention has been completed by paying attention to such points.

[0030] (Number of layers of insulation coating) When the insulating coating 2 is composed of two or three individual insulating layers each formed by overlapping two or three insulating tapes respectively (for example, when using two insulating tapes 11 and 12, they are the first insulating layer 2a and the second insulating layer 2b, and when using three insulating tapes 11, 12, and 13, they are the first insulating layer 2a to the third insulating layer 2c), the total number of turns of each individual insulating layer is configured to be not more than the total number obtained by adding 1 to the sum of the integer parts of the number of turns of each individual insulating layer.

[0031] When the insulating coating 2 is composed of four or five individual insulating layers each formed by overlapping four or five insulating tapes respectively (for example, when using four insulating tapes 11, 12, 13, and 14, they are the first insulating layer 2a to the fourth insulating layer 2d, and when using five insulating tapes 11, 12, 13, 14, and 15, they are the first insulating layer 2a to the fifth insulating layer 2e), the total number of turns of each individual insulating layer is configured to be not more than the total number obtained by adding 2 to the sum of the integer parts of the number of turns of each individual insulating layer.

[0032] The reason for treating the fractional part differently between the cases of two or three layers and four or five layers is that from the perspective of reducing the total thickness of the insulating coating to make the insulated wire thinner and ensuring that the breakdown voltage of the insulating coating is equal to or higher even when the thickness of the insulating coating is made thinner or the same, it is divided into the cases of two or three layers and four or five layers because it does not make the manufacturing complicated and is in line with the actual situation. In addition, in either case where each individual insulating layer has two or three layers or four or five layers, it is preferable that the integer part of the number of turns of each individual insulating layer is in the range of 1 to 4. The reason for setting the integer part to 1 or more is that if the minimum number of turns of each insulating layer is less than 1.0 and the integer part is not 1 or more, the minimum breakdown voltage cannot be ensured. Also, the reason for setting the integer part to 4 or less is that if the number of turns of each insulating layer exceeds 5.0, the number of turns increases, making it difficult to count the integer part and the fractional part, and the complexity in the manufacturing process increases.

[0033] In this tape-wound insulated wire 10, since the sum of the fractional parts, which are the remainders of the circumferential overlapping parts (integer parts) when the individual insulating tapes are wound around each other, is 0.0 or more and 1.0 or less or 2.0 or less, the total thickness of the insulating coating 2 can be reduced, and the resulting insulated wire 10 can be made thinner. As a result, the space factor when manufacturing a coil can be improved.

[0034] Also, even if the thickness of the insulating coating 2 is the same as that of a conventional insulated wire, since the sum of the above-mentioned fractional parts is 0.0 or more and 1.0 or less or 2.0 or less, the integer part of the circumferential overlap when the individual insulating tapes are wound around each other can be sufficiently ensured. As a result, even if the thickness of the insulating coating 2 is the same as that of a conventional insulated wire, the dielectric breakdown voltage can be made equal to or higher. Also, even if the insulated wire 10 is made thinner by reducing the thickness of the insulating coating 2 compared to a conventional insulated wire, the integer part of the circumferential overlap when the individual insulating tapes are wound around each other can be sufficiently ensured. As a result, the dielectric breakdown voltage can be made equal to or higher. Also, setting the sum of the fractional parts to 0.0 or more and 1.0 or less or 2.0 or less acts advantageously on thinning, but from the viewpoint of the minimum number of windings, the minimum number of windings can be increased by 1 or 2. As a result, the dielectric breakdown voltage can be increased. Since the dielectric breakdown voltage can be increased, if the dielectric breakdown voltage at an equivalent level is sufficient, the insulating coating 2 can be made thinner to contribute to thinning of the insulated wire 10 and improvement of the space factor of the coil.

[0035] (Conventional overlapping winding pattern) Here, a conventional tape-wound insulated wire before developing the tape-wound insulated wire 10 according to the present invention will be described. For an insulated wire tape-wound around a round conductor like a conventional tape-wound insulated wire, since it is required to be nearly circular and have a smooth surface, overlapping winding with many overlapping portions has usually been performed. In order to make the surface smooth, it has been considered desirable to increase the overlap of the tape, for example, to wind the tape so that the overlapping portion is 50% or more. Specifically, the tape has been wound in a multi-layer manner such as 1.5 to 2.0 layers, 2.5 to 3.0 layers, 3.5 to 4.0 layers, with the decimal part set to a large value so that the step generated at the tape end is less noticeable. Note that "1.5-layer winding" means that the tape is further wound on one layer and 50% of the two-layer part is wound, and "two-layer winding" means that the tape is further wound on one layer and 100% of the two-layer part is wound. Conventionally, such overlapping winding has formed a plurality of insulating layers (for example, the first to third insulating layers, or the first to fourth insulating layers). On the other hand, conventionally, overlapping windings such as 2.1-layer winding or 2.2-layer winding that slightly exceed integer winding are likely to form a step between the other two-layer parts because the tape end, which is the decimal part, becomes a slight three-layer part. If such a stepped portion is narrow, the surface of the insulated wire becomes non-smooth, so overlapping winding that slightly exceeds integer winding has not been preferred.

[0036] However, as described in the section on the above problems, in order to meet the requirement for reducing the diameter of the insulated wire, the inventor considered that the total thickness of the insulating layer could be reduced and the diameter of the insulated wire could also be reduced by making the decimal part small, such as 0.5 or less, by reducing the number of windings of the insulating tape wound around the conductor to 1.0 to 1.5 layers, 2.0 to 2.5 layers, 3.0 to 3.5 layers, 4.0 to 4.5 layers, which have a narrower (smaller) overlapping portion than the 1.5 to 2.0 layers, 2.5 to 3.0 layers, 3.5 to 4.0 layers with a wide (large) overlapping portion like the conventional insulating layers. Furthermore, since the insulating coating 2 is composed of a plurality of insulating layers, the inventor considered that it might be possible to reduce the diameter by taking into account the number of windings of the plurality of layers.

[0037] (Aspect of overlapping winding in the present invention) The winding mode of the insulating tape of the present invention based on the above-described background was described in the column of (the number of layers of the insulating coating) above. More specifically, the present invention is an insulating coating 2 formed by winding two to five insulating tapes. When (1) each of the insulating layers wound with the insulating tapes has two or three layers, the total number of turns of each insulating layer is less than or equal to the total of the integer parts of the number of turns of each insulating layer plus one. Or, (2) when each of the insulating layers wound with the insulating tapes has four or five layers, the total number of turns of each insulating layer is less than or equal to the total of the integer parts of the number of turns of each insulating layer plus two. This is the characteristic point.

[0038] First, the case where the insulating layer has two or three layers in (1) will be described. When the insulating coating 2 has two or three layers of each insulating layer wound with the insulating tapes, as described in the examples below, the first insulating layer 2a is represented as s.α turns wound with the first insulating tape 11, the second insulating layer 2b is represented as t.β turns wound with the second insulating tape 12, and the third insulating layer 2c is represented as u.γ turns wound with the third insulating tape 13. The sum of the integers s, t, and u is s + t in the case of two layers and s + t + u in the case of three layers. Also, the sum of the decimal parts α, β, and γ is α + β in the case of two layers and α + β + γ in the case of three layers. And it is configured such that the sum of the decimal parts is 1.0 or less. This relationship is that when the insulating layer has two or three layers, by making the sum of the decimal parts 1.0 or less, the sum of the number of turns of the decimal part that does not contribute to the minimum number of turns (the substantial number of turns consisting of the sum of the integer parts) is reduced to 1.0 or less, so that the diameter of the tape-wound insulated wire 10 can be reduced. Note that the minimum number of turns is the sum of the integer parts on which the breakdown voltage of the tape-wound insulated wire depends. Note that "1.0 or less" of the sum of the number of turns of the decimal part includes 0.0.

[0039] In this case, when there are two insulating tapes, the sum of the integer parts is from 2 to 8, the sum of the decimal parts is 0.0 or more and 1.0 or less, and the total of these sums is from 2.0 to 9.0. When there are three insulating tapes, the sum of the integer parts is from 3 to 12, the sum of the decimal parts is 0.0 or more and 1.0 or less, and the total of these sums is from 3.0 to 13.0.

[0040] Next, the case where the insulating layer has four or five layers in (2) will be described. Also in this aspect, as will be described in the examples below, in the case where the individual insulating layers formed by winding the insulating coating 2 with the respective insulating tapes have four or five layers, similar to the case of the two or three layers described above, the number of turns of the first insulating layer 2a with the first insulating tape 11 is represented as s.α multiple winding, the number of turns of the second insulating layer 2b with the second insulating tape 12 is represented as t.β multiple winding, the number of turns of the third insulating layer 2c with the third insulating tape 13 is represented as u.γ multiple winding, the number of turns of the fourth insulating layer with the fourth insulating tape is represented as v.δ multiple winding, and the number of turns of the fifth insulating layer with the fifth insulating tape is represented as w.ε multiple winding. When this is the case, the sum of s, t, u, v, w which are the integer parts is s + t + u + v in the case of four layers and s + t + u + v + w in the case of five layers. Also, the sum of α, β, γ, δ, ε which are the decimal parts is α + β + γ + δ in the case of four layers and α + β + γ + δ + ε in the case of five layers. And it is configured such that the sum of the decimal parts is 2.0 or less. This relationship is such that in the case where the insulating layer has four or five layers, by making the sum of the decimal parts 2.0 or less, the sum of the number of turns of the decimal parts that do not contribute to the substantial number of turns (so-called minimum number of turns) is made small to 2.0 or less, and the tape-wound insulated wire 10 can be made thinner. Note that "2.0 or less" for the sum of the number of turns of the decimal parts includes 0.0.

[0041] In this case, when there are four insulating tapes, the sum of the integer parts is from 4 to 16, the sum of the decimal parts is 0.0 or more and 2.0 or less, and the total of these sums is from 4.0 to 18.0. When there are five insulating tapes, the sum of the integer parts is from 5 to 20, the sum of the decimal parts is 0.0 or more and 2.0 or less, and the total of these sums is from 5.0 to 22.0.

[0042] The tape-wound insulated wire 10 having such an insulating coating 2 can equal or improve the breakdown voltage, is flexible, has excellent coil winding linearity, can increase the space factor, and miniaturize the coil. Also, since the insulating coating 2 can be made thin, the thermal resistance of the insulated wire is reduced, the heat dissipation property is increased, and the temperature of the insulated wire 10 can be lowered.

[0043] (Insulating tape) The insulating tape is wound around the outer periphery of the conductor 1 in multiple layers. In the present invention, "multiple" means 2 to 5. The reason for setting the number of insulating tapes in the range of 2 to 5 is that it is easy to ensure the required breakdown voltage by using at least 2 insulating tapes. Also, the reason for setting the number of insulating tapes to 5 or less is that if there are 6 or more, the complexity in the manufacturing process increases, the manufacturing cost becomes high, and it is difficult to further improve the effect. Therefore, in the present invention, the mode of winding 2 to 5 insulating tapes is described.

[0044] The material of the insulating tape is not particularly limited. For example, insulating resin materials such as polyethylene resin, polyester resin (PET, PEN, etc.), polyimide resin, polyamide resin, polyamideimide resin, polyphenylene sulfide resin, and PEEK (polyetheretherketone) can be preferably applied. Also, among these resin materials, fluorine-based resins with a low dielectric constant such as PFA, ETFE, and FEP used as dielectric materials may be used, or resins such as polyphenylene ether resin, polyolefin resins such as polypropylene, and polyester resin may be used.

[0045] The thickness of the insulating tape is not particularly limited as long as the insulating coating 2 after winding a plurality (2 to 5) of insulating tapes on top of each other can ensure the required dielectric withstand voltage. The thickness of each individual insulating tape can be, for example, about 0.002 to 0.1 mm. However, it is preferable to select the thickness of the insulating tape to be used and the number of winding layers according to the number of insulating tapes to be used and the number of times of winding, considering the final thickness of the insulating coating 2 formed by winding the insulating tapes on top of each other. When the adhesive layer 5 or the fusion layer 6 described later is provided on the insulating tape, the thickness including the thickness of the adhesive layer 5 or the fusion layer 6 is the thickness of the insulating tape. The width of the insulating tape is not particularly limited either, as long as it can be wound on the outer circumference of the conductor 1 or on top of the insulating tape already wound. For example, it is preferably a width that is 2 to 12 times the diameter of the conductor 1. Usually, the width of the insulating tape is preferably in the range of 0.4 to 50 mm. The 2 to 5 insulating tapes to be used may have the same thickness and width, or different ones may be used. The winding pitch during winding will be such that the winding form described later can be realized. The winding direction of each insulating tape is not particularly limited, but it is preferably wound in the opposite direction to the adjacent insulating tape.

[0046] (Adhesive layer) As shown in Fig. 4(A), the adhesive layer 5 can be provided on any one or two or more of the first to fifth insulating tapes as required. "As required" means that the adhesive layer 5 may or may not be provided, and it is optional.

[0047] As the insulating tape provided with the adhesive layer 5, a resin tape 4 with an adhesive layer in which the adhesive layer 5 is provided on the resin tape 4 made of the material described in the material description column of the above insulating tape is preferably used. The thickness of the adhesive layer 5 is not particularly limited, but if it is too thick, the overall thickness will become thick, so it is preferably 5 μm or less. The lower limit of the thickness of the adhesive layer is not particularly limited either, but it can be, for example, 0.5 μm.

[0048] The subsequent layer 5 may be provided on one side or both sides of the insulating tape, and is not particularly limited, but it is preferably provided on one side. The insulating tape may be wound with the side of the adhesive layer 5 provided on one side facing inward (conductor side) or outward. In the first insulating tape 11 that is wound first among the plurality of insulating tapes, winding with the side of the adhesive layer 5 provided on one side facing inward (conductor side) has the advantage of closely adhering the insulating coating 2 to the conductor 1. On the other hand, in the first insulating tape 11 that is wound first, it is also possible to wind with the side of the adhesive layer 5 provided on one side facing outward (opposite side of the conductor), which has the advantage of making it easy to peel off the insulating coating 2.

[0049] As another method, in order to make it easier to peel off the insulating coating 2, the first insulating tape 11 without an adhesive layer on the inside can be wound. In that case, there may be an adhesive layer 5 on the outside of the first insulating tape 11 and the inside of the second insulating tape 12, or there may be an adhesive layer 5 on either the outside of the first insulating tape 11 or the inside of the second insulating tape 12. The third insulating tape 13 provided with an adhesive layer 5 on one side is wound on the second insulating layer 2b so that the adhesive layer 5 is on the inside. Also in the fourth insulating tape 14 and the fifth insulating tape 15 provided with an adhesive layer 5 on one side, they are wound so that the adhesive layer 5 is on the inside.

[0050] In order to reduce the outer diameter of the insulated wire 10, an insulating tape without an adhesive layer can be used for any one of the two to five insulating tapes excluding the fifth insulating tape. For example, when there is no adhesive layer 5 on the first insulating tape 11, the second to fifth insulating tapes are wound with the adhesive layer on the inside. When there is no adhesive layer 5 on the second insulating tape 12, the first insulating tape 11 is wound with the adhesive layer 5 on the outside, and the third to fifth insulating tapes are wound with the adhesive layer 5 on the inside. Similarly, when there is no adhesive layer 5 on the third insulating tape 13 or the fourth insulating tape 14, the insulating tape inside the insulating layer without the adhesive layer 5 is wound with the adhesive layer 5 on the outside, and the insulating tape outside the insulating layer without the adhesive layer 5 is wound with the adhesive layer 5 on the inside. In this way, a strong insulating coating 2 can be formed.

[0051] In order to further reduce the outer diameter of the insulated wire 10 and maintain the shape of the insulating layer, an insulating tape provided with an adhesive layer 5 inside the outermost insulating tape can be used. As a result, the adhesive layer of the insulating tape of other insulating layers (layers other than the outermost layer, for example, in the case of a 5-layer winding, it means that an adhesive layer is provided in the fifth layer and no adhesive layer is provided in the first to fourth layers.) can be eliminated to form a flexible insulating coating.

[0052] The material of the adhesive layer 5 is preferably selected from thermoplastic resins such as acrylic, polyester, urethane, polyimide, PVC, EVA, and thermosetting resins such as epoxy and bismaleimide. The adhesive layer 5 can be formed by applying an adhesive paint in which these resins are dissolved in an organic solvent to a predetermined thickness using a coating device such as gravure printing. Note that the adhesive layer 5 can be adhered by heating or the like when the insulating tape is wound around the conductor 1 or after winding.

[0053] (Fusion layer) As shown in FIG. 4(B), the fusion layer 6 can be provided as needed on any one or two or more of the two to five insulating tapes. The fusion layer 6 may be provided in place of the adhesive layer 5 described above. Usually, a resin tape 4 with a fusion layer 6 provided thereon, which is made of the material described in the description column of the material of the insulating tape above, can be adopted. The fusion layer 6 is preferably provided outwardly on the insulating tape wound last among the plurality of insulating tapes. By doing so, when a coil is made of the obtained tape-wound insulated wire 10, the fusion layer 6 can be melted to fix the insulated wires to each other.

[0054] The material of the fusion layer 6 is preferably a thermoplastic resin composition or a resin composition mainly composed of a thermoplastic resin, which can temporarily bond the insulating tapes while maintaining thermoplasticity at a certain temperature, for example, a temperature of 80 to 130 °C, and has the property that a crosslinking reaction occurs at a temperature above a specific temperature, for example, a temperature of 160 to 200 °C, to self-fuse and bond the insulating wires 10, 10 to each other. When the fusion layer 6 has such properties, the insulating tapes can be temporarily bonded to maintain the shape as a self-fusing tape-wound insulating wire, and after the coil winding during the manufacture of the coil, the crosslinking reaction can occur by raising the temperature above a specific temperature to bond the self-fusing insulating wires to each other, and the coil shape after winding can be maintained.

[0055] Examples of the material of the fusion layer 6 include thermosetting resins such as polyurethane resin, polyamide resin, polyester resin, and polyesterimide resin. Among these, polyurethane resin and polyester resin are preferred. The resin composition for forming the fusion layer 6 that forms the fusion layer 6 contains a crosslinking agent and a solvent. Further, various additives are contained as required. These crosslinking agents, solvents, and additives are not particularly limited, and various crosslinking agents, solvents, and additives corresponding to the types of polyurethane resin, polyester resin, polyesterimide resin, etc. and their required properties (the above properties) are used as required. The thickness of the fusion layer 6 is not particularly limited, but if it is too thick, the outer diameter of the insulating wire 10 will increase, so it is preferably in the range of 1 to 15 μm, for example.

[0056] [Coil] As shown in Fig. 5, the coil 20 according to the present invention is a transformer coil using the above-described insulated wire 10 according to the present invention, and can be obtained by winding the insulated wire 10 around a transformer bobbin 21. The coil 20 thus obtained is wound with the above-described tape-wound insulated wire 10, so that the breakdown voltage is equivalent or improved, the productivity is high, and a small-sized coil with a high space factor can be obtained. Further, a high-voltage-resistant transformer that satisfies the standard of IEC62368 can be manufactured without winding an interlayer paper between the primary winding and the secondary winding as in the prior art. As a result, it can be preferably used as a coil for a transformer with high insulation, a winding component such as a high-frequency coil, a circuit board provided with a winding component such as a high-frequency coil, etc.

Example

[0057] The present invention will be described more specifically with reference to Examples and Comparative Examples. The present invention is not limited to the following examples, and those skilled in the art can make various changes, modifications, and alterations within the scope of the present invention. In addition, in FIGS. 6 to 9 for explaining the forms of the Examples and Comparative Examples, coordinates are attached vertically and horizontally to make it easier to understand the position of the end of the insulating tape. It is represented as (x, y) in those coordinates, where "x" is the numerical value of the horizontal coordinate and "y" is the numerical value of the vertical coordinate.

[0058] [Example 1] The tape-wound insulated wire 10 of Example 1 will be described with reference to Fig. 6. A copper conductor with a diameter of 1.00 mm was used as the conductor 1, and an insulating coating 2 was provided on its outer periphery. The insulating coating 2 was composed of three insulating layers (2a, 2b, 2c) formed by overlapping three insulating tapes (11, 12, 13) of the first to the third. The first insulating layer 2a closest to the conductor 1 was formed by overlapping the first insulating tape 11, the second insulating layer 2b outside thereof was formed by overlapping the second insulating tape 12, and the third insulating layer 2c outside thereof was formed by overlapping the third insulating tape 13.

[0059] A first insulating tape 11 made of polyimide resin with a thickness of 7.5 μm (total thickness 9.5 μm) and a tape width of 7.0 mm, provided with an adhesive layer with a thickness of 2 μm, was wound 2.3 times on conductor 1 with the adhesive layer facing outward so that it does not adhere to conductor 1, and a first insulating layer 2a was provided. From the coordinates in Fig. 6, the coordinates of the ends of the first insulating tape 11 forming the first insulating layer 2a are (10, 3) and (32, 1), the coordinates of the ends of the first insulating tape 11 when wound half a turn are (15, -3) and (37, -1), and the coordinates of the ends of the first insulating tape 11 when wound another half turn are (20, 3) and (42, 1). Since the first insulating layer 2a is a 2.3 - wound layer, on the upper side of conductor 1 shown in Fig. 6, at x - coordinates 1 - 2, 10 - 12, 20 - 22, 30 - 32, 40 - 42, it is wound three - times, and at other locations it is wound two - times. On the lower side of conductor 1, at x - coordinates 5 - 7, 15 - 17, 25 - 27, 35 - 37, 45 - 46, it is wound three - times, and at other locations it is wound two - times.

[0060] Next, a second insulating tape 12 made of polyimide resin with a thickness of 7.5 μm (total thickness 9.5 μm) and a tape width of 7.0 mm, provided with an adhesive layer with a thickness of 2 μm, was placed with its adhesive layer facing inward so that it adheres to the first insulating layer 2a, and was wound 2.2 times on the first insulating layer 2a in a winding direction different from that of the first insulating tape 11, and a second insulating layer 2b was provided. In Fig. 6, a state where the second insulating tape 12 is along the end of the first insulating layer 2a can be seen. The coordinates of the ends of the second insulating tape 12 forming the second insulating layer 2b are (8, 5) and (29, 3), the coordinates of the ends of the second insulating tape 12 when wound half a turn are (13, -5) and (34, -3), and the coordinates of the ends of the second insulating tape 12 when wound another half turn are (18, 5) and (39, 3). Since the second insulating layer 2b is a 2.2 - wound layer, on the upper side of conductor 1 shown in Fig. 6, at x - coordinates 8 - 9, 18 - 19, 28 - 29, 38 - 39, it is wound three - times, and at other locations it is wound two - times. On the lower side of conductor 1, at x - coordinates 3 - 4, 13 - 14, 23 - 24, 33 - 34, 43 - 44, it is wound three - times, and at other locations it is wound two - times.

[0061] Next, a third insulating tape 13 made of polyimide resin with a thickness of 7.5 μm (total thickness 9.5 μm) and a tape width of 7.0 mm, provided with an adhesive layer having a thickness of 2 μm, was placed inside with its adhesive layer adhered to the second insulating layer 2b. The winding direction was changed from that of the second insulating tape 12, and it was wound 2.3 times on the second insulating layer 2b to form a third insulating layer 2c. In FIG. 6, it can be seen that the third insulating tape 13 is along the edge of the second insulating layer 2b. The coordinates of the ends of the third insulating tape 13 forming the third insulating layer 2c are (5,7) and (27,5). The coordinates of the ends of the third insulating tape 13 when wound half a turn are (10, -7) and (32, -5). The coordinates of the ends of the third insulating tape 13 when wound another half turn are (15,7) and (37,5). Since the third insulating layer 2c is wound 2.3 times, on the upper side of the conductor 1 shown in FIG. 6, at x coordinates 5 - 7, 15 - 17, 25 - 27, 35 - 37, 45 - 46, it is wound three times, and the other parts are wound twice. On the lower side of the conductor 1, at x coordinates 1 - 2, 10 - 12, 20 - 22, 30 - 32, 40 - 42, it is wound three times, and the other parts are wound twice. Thus, the tape-wound insulated wire of Example 1 was obtained.

[0062] In the obtained tape-wound insulated wire, the average thickness at each part in the longitudinal direction T of the insulation coating 2 having the first insulating layer 2a, the second insulating layer 2b, and the third insulating layer 2c was 64 μm. The total (minimum number of turns) of the integer parts of the number of turns of the first insulating layer 2a, the second insulating layer 2b, and the third insulating layer 2c was 2 + 2 + 2 = 6. The number of turns of the fractional parts was all 0.5 or less, and the total of the fractional parts was 0.8 which was 1.0 or less. The total number of turns obtained by adding them up was 6.8, which was 7 or less when 1 was added to the total of the integer parts. The number of turns of each insulating layer can be understood from FIG. 2(B). The symbol 1 is the conductor, and the first insulating tape 11 is wound 2.3 times clockwise around it. The second insulating tape 12 is wound 2.2 times counterclockwise outside it, and the third insulating tape 13 is wound 2.3 times clockwise outside it.

[0063] [Comparative Example 1] The tape-wound insulated wire 10 of Comparative Example 1 will be described with reference to FIG. 7. A copper wire with a diameter of 1.00 mm was used as the conductor 1, and the insulating coating 2 provided on the outer periphery thereof was composed of three insulating layers (2a, 2b, 2c) formed by winding three insulating tapes (11, 12, 13) of the first to the third. The first insulating tape 11 made of polyimide resin with a thickness of 7.5 μm (total thickness of 9.5 μm) and a tape width of 8.5 mm provided with an adhesive layer with a thickness of 2 μm was wound 2.8 times on the conductor 1 with the outer side such that the adhesive layer did not adhere to the conductor 1, thereby providing the first insulating layer 2a. Next, the second insulating tape 12 made of polyimide resin with a thickness of 7.5 μm (total thickness of 9.5 μm) and a tape width of 7.5 mm provided with an adhesive layer with a thickness of 2 μm was placed inside such that the adhesive adhered to the first insulating layer 2a, and was wound 2.3 times on the first insulating layer 2a with a winding direction different from that of the first insulating tape 11, thereby providing the second insulating layer 2b. Next, the third insulating tape 13 made of polyimide resin with a thickness of 7.5 μm (total thickness of 9.5 μm) and a tape width of 6.0 mm provided with an adhesive layer with a thickness of 2 μm was placed inside such that the adhesive layer adhered to the second insulating layer 2b, and was wound 1.8 times on the second insulating layer 2b with a winding direction different from that of the second insulating tape 12, thereby providing the third insulating layer 2c. Thus, the tape-wound insulated wire of Comparative Example 1 was obtained.

[0064] In the obtained tape-wound insulated wire, the average thickness at each part in the longitudinal direction T of the insulating coating 2 having the first insulating layer 2a, the second insulating layer 2b, and the third insulating layer 2c was 64 μm. The sum of the integer part of the number of windings (minimum number of windings) of the first insulating layer 2a, the second insulating layer 2b, and the third insulating layer 2c was 2 + 2 + 1 = 5, and the sum of the number of windings of the fractional part exceeded 1.0 and was 1.9. The total number of windings obtained by adding these together was 6.9, which exceeded 6, the total obtained by adding 1 to the sum of the integer parts.

[0065] [Example 2] The tape-wound insulated wire 10 of Example 2 will be described with reference to FIG. 8. A copper conductor with a diameter of 0.55 mm was used as the conductor 1, and the insulating coating 2 provided on the outer periphery thereof was composed of two insulating layers (2a, 2b) formed by winding the first insulating tape 11 and the second insulating tape 12 in layers. The first insulating tape 11 made of polyimide resin with a thickness of 7.5 μm (total thickness of 9.5 μm) and a tape width of 5.5 mm provided with an adhesive layer having a thickness of 2 μm was wound 3.2 times on the conductor 1 with the adhesive layer facing outward so as not to adhere to the conductor 1, thereby providing the first insulating layer 2a. Next, the second insulating tape 12 made of polyimide resin with a thickness of 7.5 μm (total thickness of 9.5 μm) and a tape width of 4.0 mm provided with an adhesive layer having a thickness of 2 μm was wound 2.1 times on the first insulating layer 2a with the adhesive facing inward so as to adhere to the first insulating layer 2a, and the winding direction was changed from that of the first insulating tape 11, thereby providing the second insulating layer 2b. The third insulating layer was not provided. Thus, the tape-wound insulated wire of Example 2 was obtained.

[0066] In the obtained tape-wound insulated wire, the average thickness at each part in the longitudinal direction T of the insulating coating 2 having the first insulating layer 2a and the second insulating layer 2b was 48 μm. The sum of the integer parts of the number of windings (minimum number of windings) of the first insulating layer 2a and the second insulating layer 2b was 3 + 2 = 5, the number of windings in the fractional part was 0.5 or less for each, and the total of the fractional parts was 0.3 which was 1.0 or less. The total number of windings obtained by adding them up was 5.3, which was 6 or less, the total of the integer parts plus 1.

[0067] [Comparative Example 2] The tape-wound insulated wire 10 of Comparative Example 2 will be described with reference to FIG. 9. A copper wire with a diameter of 0.55 mm was used as the conductor 1, and the insulating coating 2 provided on the outer periphery thereof was composed of three insulating layers (2a, 2b, 2c) obtained by winding three insulating tapes (11, 12, 13) of the first to third layers. The first insulating tape 11 made of polyimide resin with a thickness of 7.5 μm (total thickness of 9.5 μm) and a tape width of 3.0 mm provided with an adhesive layer with a thickness of 2 μm was wound 1.9 times on the conductor 1 with the outer side such that the adhesive layer did not adhere to the conductor 1, thereby providing the first insulating layer 2a. Next, the second insulating tape 12 made of polyimide resin with a thickness of 7.5 μm (total thickness of 9.5 μm) and a tape width of 5.0 mm provided with an adhesive layer with a thickness of 2 μm was placed on the inner side such that the adhesive adhered to the first insulating layer 2a, and was wound 2.7 times on the first insulating layer 2a in a winding direction different from that of the first insulating tape 11, thereby providing the second insulating layer 2b. Next, the third insulating tape 13 made of polyimide resin with a thickness of 7.5 μm (total thickness of 9.5 μm) and a tape width of 3.5 mm provided with an adhesive layer with a thickness of 2 μm was placed on the inner side such that the adhesive layer adhered to the second insulating layer 2b, and was wound 1.8 times on the second insulating layer 2b in a winding direction different from that of the second insulating tape 12, thereby providing the third insulating layer 2c. Thus, the tape-wound insulated wire of Comparative Example 2 was obtained.

[0068] In the obtained tape-wound insulated wire, the average thickness at each part in the longitudinal direction T of the insulating coating 2 having the first insulating layer 2a, the second insulating layer 2b, and the third insulating layer 2c was 57 μm. The sum of the integral parts of the number of windings (minimum number of windings) of the first insulating layer 2a, the second insulating layer 2b, and the third insulating layer 2c was 1 + 2 + 1 = 4, the number of windings in the fractional part of each exceeded 0.5, and the sum of the fractional parts was 2.4 exceeding 1.0. The total number of windings obtained by adding up these was 6.4, exceeding 5 which is the total number obtained by adding 1 to the sum of the integral parts.

[0069] [Example 3] As the conductor 1, a litz wire formed by twisting 33 copper wires with a diameter of 0.1 mm was used. As the insulating coating 2 provided on the outer periphery thereof, it was composed of two insulating layers (2a, 2b) obtained by overlapping and winding a first insulating tape 11 and a second insulating tape 12. The first insulating tape 11 made of polyimide resin with a thickness of 7.5 μm (total thickness of 9.5 μm) and a tape width of 6.5 mm, provided with an adhesive layer having a thickness of 2 μm, was wound 3.2 times on the conductor 1 with the adhesive layer facing outward so as not to adhere to the conductor 1, thereby providing the first insulating layer 2a. Next, the second insulating tape 12 made of polyimide resin with a thickness of 7.5 μm (total thickness of 9.5 μm) and a tape width of 7.0 mm, provided with an adhesive layer having a thickness of 2 μm, was placed with the adhesive facing inward so as to adhere to the first insulating layer 2a, and was wound 3.1 times on the first insulating layer 2a in a winding direction different from that of the first insulating tape 11, thereby providing the second insulating layer 2b. A third insulating layer was not provided. Thus, the tape-wound insulated wire of Example 3 was obtained.

[0070] In the obtained tape-wound insulated wire, the average thickness at each part in the longitudinal direction T of the insulating coating 2 having the first insulating layer 2a and the second insulating layer 2b was 63 μm. The sum (minimum number of turns) of the integer parts of the number of turns of the first insulating layer 2a and the second insulating layer 2b was 3 + 3 = 6, and the number of turns of the fractional parts was all 0.5 or less, and the total was 0.3 which was 1.0 or less. The total number of turns obtained by adding these together was 6.3, which was 7 or less when 1 was added to the sum of the integer parts.

[0071] [Example 4] A copper wire with a diameter of 0.45 mm was used as the conductor 1, and the insulation coating 2 provided on its outer periphery was composed of two insulation layers (2a, 2b) formed by winding the first insulation tape 11 and the second insulation tape 12 in layers. The first insulation tape 11 made of polyimide resin with a thickness of 5.0 μm (total thickness of 7.5 μm) and a tape width of 4.8 mm, on which an adhesive layer with a thickness of 2.5 μm was provided, was wound 3.4 times on the conductor 1 with the adhesive layer facing outward so as not to adhere to the conductor 1, thereby providing the first insulation layer 2a. Next, the second insulation tape 12 made of polyimide resin with a thickness of 5.0 μm (total thickness of 7.5 μm) and a tape width of 4.8 mm, on which an adhesive layer with a thickness of 2.5 μm was provided, was wound 3.1 times on the first insulation layer 2a with the adhesive facing inward so as to adhere to the first insulation layer 2a, and the winding direction was changed from that of the first insulation tape 11, thereby providing the second insulation layer 2b. The third insulation layer was not provided. Thus, the tape-wound insulated wire of Example 4 was obtained.

[0072] In the obtained tape-wound insulated wire, the average thickness at each part in the longitudinal direction T of the insulation coating 2 having the first insulation layer 2a and the second insulation layer 2b was 51 μm. The sum of the integral number of winding turns (minimum number of winding turns) of the first insulation layer 2a and the second insulation layer 2b was 3 + 3 = 6, and the fractional number of winding turns of each was 0.5 or less, and the total was 0.5 or less than 1.0. The total number of winding turns obtained by adding these together was 6.5, which was 7 or less than the total of the integral part plus 1.

[0073] [Inter-wire withstand voltage test] For Examples 1 to 4 and Comparative Examples 1 and 2, samples were prepared by twisting two tape-wound insulated wires. After applying 8 kV for 1 minute as specified in the reinforced insulation test, the test voltage was applied between the conductors at a voltage increase rate of 500 V / s, and the breakdown voltage was measured. The measurement was performed using a withstand voltage tester (manufactured by Tokyo Seiden Co., Ltd.) based on JIS C 3216 (Winding Test Method). The results are shown in Table 1. In Table 1, "tape thickness" is the thickness of the insulating tape excluding the thickness of the adhesive layer, "total tape thickness" is the total thickness of the insulating tape including the thickness of the adhesive layer, "integer" is the sum of the integer parts (minimum number of turns) in each insulating layer, "decimal" is the sum of the decimal parts in each insulating layer, "total number" is the sum of "integer" and "decimal", and "coating thickness" is the total thickness of the insulation coating including the first to third layers.

[0074]

Table 1

[0075] The breakdown voltage in Example 1 was 16.95 kV, which was 1.38 kV higher than 15.57 kV in Comparative Example 1. Both have the same first to third insulating layers (2a, 2b, 2c) for the insulating coating 2, the same thickness of the insulating coating 2, and the same total number (sum of the integer part and the decimal part). However, in Example 1, the decimal part is 0.8 which is 1.0 or less, while in Comparative Example 1, the decimal part is 1.9 which exceeds 1.0. Since the sum of the integer parts (minimum number of turns) on which the breakdown voltage depends is larger in Example 1, it can be said that the breakdown voltage in Example 1 is higher than that in Comparative Example 1. From the results of Example 2 and Comparative Example 2, it can be seen that even when the coating thickness and the total number (sum of the integer part and the decimal part) are the same, a high breakdown voltage can be obtained by setting the sum of the decimal parts to 1.0 or less and increasing the sum of the integer parts.

[0076] The breakdown voltage was 21.30 kV in Example 2, which was 4.99 kV higher than 16.31 kV in Comparative Example 2. The thickness of the insulation coating 2 was 48 μm in Example 2 and 57 μm in Comparative Example 2. Despite the fact that Example 2 was 9 μm thinner than Comparative Example 2, the breakdown voltage was 4.99 kV higher. This is because the sum of the integer parts (minimum number of windings) on which the breakdown voltage of Example 2 depends is 5, which is larger than 4 in Comparative Example 2. From the results of Example 2 and Comparative Example 2, it can be seen that if the sum of the decimal parts is set to 1.0 or less and the sum of the integer parts is increased, a sufficient breakdown voltage can be obtained even with a thinner coating thickness.

[0077] The breakdown voltage was 21.5 kV in Example 3 and 22.86 kV in Example 4. These are both cases where the sum of the decimal parts is 1.0 or less and the sum of the integer parts is increased, indicating that a sufficient breakdown voltage can be obtained. Furthermore, in Example 4, the thickness of the insulating tape was reduced to decrease the total thickness of the insulation coating 2 for a smaller diameter. Even in this case, it can be seen that a sufficient breakdown voltage can be obtained by setting the sum of the decimal parts to 1.0 or less and increasing the sum of the integer parts.

[0078] [Examples 5 to 11] Two to five of the same insulating tapes as the first insulating tape 11 in Example 1 were arbitrarily used, and the number of windings of each insulating layer wound with each insulating tape was changed. Otherwise, in the same manner as in Example 1, the insulated electric wires 10 of Examples 5 to 11 in the forms shown in FIGS. 2 and 3 were produced. The number of windings of each insulating layer is shown in Table 2. In Table 2, the "integer part" is the sum of the integer parts in each insulating layer, the "decimal part" is the sum of the decimal parts in each insulating layer, and the "total number" is the sum of the sum of the integer parts and the sum of the decimal parts.

[0079] The insulated electric wire 10 of Example 5 was formed by winding the first insulating tape 11 4.3 times to form the first insulating layer 2a, and then winding the second insulating tape 12 4.2 times on top of it to form the second insulating layer 2b. The sum of the integer parts was 8, the sum of the decimal parts was 0.5, and the total number, which is their sum, was 8.5.

[0080] The insulated wire 10 of Example 6 is formed by winding the first insulating tape 11 1.5 times to form the first insulating layer 2a, and then winding the second insulating tape 12 1.4 times thereon to form the second insulating layer 2b. The sum of the integer parts is 2, the sum of the decimal parts is 0.9, and the total sum is 2.9.

[0081] The insulated wire 10 of Example 7 is formed by winding the first insulating tape 11 3.3 times to form the first insulating layer 2a, winding the second insulating tape 12 3.2 times thereon to form the second insulating layer 2b, and then winding the third insulating tape 13 3.3 times thereon to form the third insulating layer 2c. The sum of the integer parts is 9, the sum of the decimal parts is 0.8, and the total sum is 9.8.

[0082] The insulated wire 10 of Example 8 is formed by winding the first insulating tape 11 4.2 times to form the first insulating layer 2a, winding the second insulating tape 12 4.4 times thereon to form the second insulating layer 2b, winding the third insulating tape 13 3.3 times thereon to form the third insulating layer 2c, and then winding the fourth insulating tape 14 3.4 times thereon to form the fourth insulating layer 2d. The sum of the integer parts is 14, the sum of the decimal parts is 1.3, and the total sum is 15.3.

[0083] The insulated wire 10 of Example 9 is formed by winding the first insulating tape 11 2.3 times to form the first insulating layer 2a, winding the second insulating tape 12 2.4 times thereon to form the second insulating layer 2b, winding the third insulating tape 13 1.3 times thereon to form the third insulating layer 2c, and then winding the fourth insulating tape 14 1.4 times thereon to form the fourth insulating layer 2d. The sum of the integer parts is 6, the sum of the decimal parts is 1.4, and the total sum is 7.4.

[0084] The insulated wire 10 of Example 10 is formed by winding the first insulating tape 11 two and three-tenths times to form the first insulating layer 2a, winding the second insulating tape 12 two and two-tenths times thereon to form the second insulating layer 2b, winding the third insulating tape 13 two and three-tenths times thereon to form the third insulating layer 2c, winding the fourth insulating tape 14 two and four-tenths times thereon to form the fourth insulating layer 2d, and winding the fifth insulating tape 15 two and two-tenths times thereon to form the fifth insulating layer 2e. The sum of the integer parts is 10, the sum of the decimal parts is 1.4, and the total number, which is their sum, is 11.4.

[0085] The insulated wire 10 of Example 11 is formed by winding the first insulating tape 11 two and three-tenths times to form the first insulating layer 2a, winding the second insulating tape 12 one and three-tenths times thereon to form the second insulating layer 2b, winding the third insulating tape 13 one and three-tenths times thereon to form the third insulating layer 2c, winding the fourth insulating tape 14 one and four-tenths times thereon to form the fourth insulating layer 2d, and winding the fifth insulating tape 15 two and three-tenths times thereon to form the fifth insulating layer 2e. The sum of the integer parts is 7, the sum of the decimal parts is 1.7, and the total number, which is their sum, is 8.7.

[0086]

Table 2

[0087] From the results in Table 2, two to five insulating tapes can be arbitrarily adopted, and the number of windings of each insulating tape wound on top of each other can be arbitrarily designed to constitute the insulating tape according to the present invention. By doing so, the effects of the present invention described above can be realized with a high degree of design freedom.

Explanation of Reference Numerals

[0088] 1 Conductor 2 Insulation Coating 2a First Insulating Layer 2b Second Insulating Layer 2c Third Insulating Layer 2d Fourth Insulating Layer 2e Fifth Insulating Layer 4 Resin Tape 5 Adhesive Layer 6 Fused Layer 10 Tape-wound insulated wire 11 First insulating tape 12 Second insulating tape 13 Third insulating tape 14 Fourth insulating tape 15 Fifth insulating tape 20 Coil 21 Transformer bobbin T Longitudinal direction

Claims

1. An insulated wire having a conductor and an insulating coating on the outer periphery of the conductor, wherein the insulating coating is composed of a plurality of insulating layers wound with 2 to 5 insulating tapes, When the insulating coating has 2 or 3 individual insulating layers wound with each insulating tape, the total number of turns of the individual insulating layers is less than or equal to the total of the integer parts of the number of turns of the individual insulating layers plus 1; or when the insulating coating has 4 or 5 individual insulating layers wound with each insulating tape, the total number of turns of the individual insulating layers is less than or equal to the total of the integer parts of the number of turns of the individual insulating layers plus 2, and in any case where the individual insulating layers are 2 to 5 layers, the integer part of the number of turns is in the range of 1 to 4. A tape-wound insulated wire characterized by this.

2. When the insulating coating has 2 or 3 individual insulating layers wound with each insulating tape, the number of turns with the first insulating tape is represented as s.α double winding, the number of turns with the second insulating tape is represented as t.β double winding, and the number of turns with the third insulating tape is represented as u.γ double winding. When this is the case, the total of the integer parts is s + t when the insulating layer is 2 layers, and s + t + u when the insulating layer is 3 layers. The total of the decimal parts is α + β when the insulating layer is 2 layers, and α + β + γ when the insulating layer is 3 layers, and the total of the decimal parts is 1.0 or less. The tape-wound insulated wire according to Claim 1.

3. When there are 2 insulating tapes, the total of the integer parts is 2 to 8, the total of the decimal parts is 1.0 or less, and the total number is 2.0 to 9.

0. When there are 3 insulating tapes, the total of the integer parts is 3 to 12, the total of the decimal parts is 1.0 or less, and the total number is 3.0 to 13.

0. The tape-wound insulated wire according to Claim 2.

4. When the individual insulating layers obtained by winding the insulating coating with each of the insulating tapes are four or five layers, the number of turns with the first insulating tape is represented as s.α multiple winding, the number of turns with the second insulating tape is represented as t.β multiple winding, the number of turns with the third insulating tape is represented as u.γ multiple winding, the number of turns with the fourth insulating tape is represented as v.δ multiple winding, and the number of turns with the fifth insulating tape is represented as w.ε multiple winding, the sum of the integer parts is s + t + u + v when the insulating layer is four layers, and s + t + u + v + w when the insulating layer is five layers. The sum of the fractional parts is α + β + γ + δ when the insulating layer is four layers, and α + β + γ + δ + ε when the insulating layer is five layers. The sum of the fractional parts is 2.0 or less. The tape-wound insulated wire according to claim 1.

5. When there are four insulating tapes, the sum of the integer parts is 4 to 16, the sum of the fractional parts is 2.0 or less, and the total sum is 4.0 to 18.

0. When there are five insulating tapes, the sum of the integer parts is 5 to 20, the sum of the fractional parts is 2.0 or less, and the total sum is 5.0 to 22.

0. The tape-wound insulated wire according to claim 4.

6. For any one or two or more of the two to five insulating tapes, an adhesive layer is provided on one side. The tape-wound insulated wire according to any one of claims 1 to 5.

7. For the insulating tape wound last among the plurality of insulating tapes, a fusion layer is provided on the outward-facing surface. The tape-wound insulated wire according to any one of claims 1 to 5.

8. A coil obtained by winding the tape-wound insulated wire according to any one of claims 1 to 5.

9. A coil obtained by winding the tape-wound insulated wire according to claim 6.

10. A coil obtained by winding the tape-wound insulated wire according to claim 7.

Images