Insulated wire, coil using said insulated wire, thickness-changing insulating tape used for manufacturing said insulated wire, and method for manufacturing said insulated wire

Abstract

[Problem] To provide: an insulated wire capable of increasing a partial discharge start voltage, preventing the deterioration of an insulating body, and not deteriorating a space factor; a coil using the insulated wire; a thickness changing insulating tape used in manufacturing the insulated wire; and a method for manufacturing the thickness changing insulating tape. [Solution] The above problem is solved by an insulated wire 10 for a coil, which has a conductor 1 and insulating coverings 2, 3 provided on the outer circumference of the conductor 1 and is constituted by the thick insulating covering 3 for a region where voltage increases and a partial discharge easily occurs when wound into a coil and the thin insulating covering 2 for a region where the voltage does not increase and the partial discharge hardly occurs, wherein the the thick insulating covering 3 and the thin insulating covering 2 are repeatedly provided at arbitrary intervals. The above problem is also solved by a coil 40 which is obtained by winding this insulated wire 10 and formed so that the insulating covering 3 of the insulated wire 10 in the region where the partial discharge easily occurs is thick and the insulating covering 2 of the insulated wire 10 in the region where the partial discharge hardly occurs is thin.

Description

[Technical field]

[0001] The present invention relates to an insulated electric wire in which the thickness of an insulating coating can be arbitrarily changed in order to increase the partial discharge (corona discharge) inception voltage, a coil using the insulated electric wire, a variable thickness insulating tape used in the manufacture of the insulated electric wire, and a manufacturing method thereof. [Background technology]

[0002] Insulated wires are used in a variety of products. When insulated wires are used as coil windings for rotating electrical equipment such as motors, they are used under high voltage. In such cases, intense partial discharges (corona discharges) can occur on the insulating surface. Such partial discharges occur when localized temperature increases and ozone and ions are generated, causing accelerated deterioration of the insulating coating. The occurrence of partial discharges poses the problem of shortening the life of the equipment in which the parts are used.

[0003] In recent years, with the increasing demand for small, high-power motors, there is a demand for coils that can be applied with a higher voltage. However, when the applied voltage is increased, the voltage applied to the coil increases, making partial discharges more likely to occur. To address this issue, it is desirable to increase the voltage at which partial discharges occur (called the partial discharge inception voltage), and in order to increase the partial discharge inception voltage, various methods have been used, such as thickening the insulation coating of enameled wires, thickening the insulation coating by resin extrusion, and lowering the dielectric constant of the insulation coating by foaming. However, each of these methods reduces the space factor of the coil winding or the strength of the coating, and there is a limit to how much the partial discharge inception voltage can be increased.

[0004] Partial discharges are likely to occur when a high voltage is applied to a "jump" that connects the stator slot conductors of a motor (a slot conductor refers to the arrangement of an electric wire in a slot.) To solve this problem, for example, Patent Documents 1 and 2 describe how partial discharges and the like can be suppressed by changing the thickness and material of the insulating material between the slot conductors and the jumpers of an insulated electric wire.

[0005] Specifically, Patent Document 1 describes a method in which a conductor is wound into a coil shape and then molded, and then insulating layers are formed in each of the portions that will become the slot conductor portions and the jumper portions, and the thickness of each insulating layer is changed. Patent Document 2 describes a method in which the relative dielectric constant of the portions that will become the jumper portions in the longitudinal direction of an insulated electric wire is made lower than the relative dielectric constant of the portions that will become the slot conductor portions by adjusting the total volume of the resin bubbles that form the insulating layer. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2008-236924 A [Patent Document 2] JP 2015-138678 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in order to manufacture an insulated electric wire having an insulating layer capable of exhibiting the insulating performance required at the time of coil design, the above-mentioned manufacturing method of the insulated electric wire requires many man-hours and complicated processes. Also, it is difficult to manufacture an insulated electric wire having an insulating coating of a variable thickness so as to exhibit the insulating performance required at the time of coil design by enamel baking means or resin extrusion means.

[0008] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an insulated electric wire that can be manufactured without many man-hours or complicated processes, that can increase the partial discharge inception voltage, that can prevent deterioration of the insulator, and that does not deteriorate the space factor, a coil using the insulated electric wire, a variable-thickness insulating tape used to manufacture the insulated electric wire, and a manufacturing method thereof. [Means for solving the problem]

[0009] (1) The insulated wire according to the present invention is an insulated wire having a conductor and an insulating coating provided around the conductor, characterized in that the insulated wire is made up of a thick insulating coating and a thin insulating coating, and the thick insulating coating and the thin insulating coating are provided repeatedly at any intervals.

[0010] According to the present invention, since the thick insulating coating and the thin insulating coating are repeatedly provided at an arbitrary interval, the insulating coating can be made thicker in the area where partial discharge is likely to occur or where a high dielectric strength voltage is required. As a result, for example, the partial discharge inception voltage at the jumper section can be increased, and the dielectric strength voltage at the area where a high dielectric strength voltage is required can be increased. In addition, the insulating coating can be made thinner in the slot conductor section or the area where a high dielectric strength voltage is not required, and the space factor can be increased without deteriorating. Since these areas are repeatedly provided at an arbitrary interval, for example, when the coil is preferably applied as a coil for a three-phase induction motor, the slot conductor section of the motor can have a thin insulating coating, and the jumper section connecting the slot conductor sections of the motor to which a high voltage is applied can have a thick insulating coating.

[0011] In the insulated wire according to the present invention, the thick insulating coating and the thin insulating coating are formed by winding an insulating tape having thick and thin regions at a predetermined interval (hereinafter referred to as a "varied thickness insulating tape") around the outer periphery of the conductor. According to this invention, by winding the variable thickness insulating tape around the outer periphery of the conductor, an insulated wire can be obtained in which thick and thin insulating coatings are provided repeatedly at any interval.

[0012] In the insulated wire according to the present invention, the thick insulating coating and the thin insulating coating are configured to have different visibility. According to this invention, by making the visibility different depending on the thickness of the insulating coating, it becomes possible to distinguish between the thin insulating coating and the thick insulating coating. As a result, the thin insulating coating and the thick insulating coating can be distinguished by an operator or a discrimination sensor during coil production, making the coil production process easier.

[0013] In the insulated wire according to the present invention, the variable thickness insulating tape is composed of a base tape and a laminating tape laminated on one main surface of the base tape, or is composed of a base tape, a laminating tape laminated on one main surface of the base tape, and a cover tape laminated on the laminating tape in a manner covering the laminating tape. According to this invention, the variable thickness insulating tape can be made to have a simple structure composed of a base tape and a laminating tape, or a so-called sandwich structure composed of a base tape, a laminating tape, and a cover tape.

[0014] In the insulated wire according to the present invention, the variable thickness insulating tape further has an adhesive layer formed on one main surface of the base tape and on the laminating tape or on the other main surface of the base tape, and the variable thickness insulating tape first wound around the outer circumference of the conductor is wound with the adhesive layer on the inner conductor side or on the outer side, and another variable thickness insulating tape provided on top of it is wound with the laminating tape side on the inner side and the adhesive layer on the inner side. According to this invention, the other main surface on the flat side of the base tape can be firmly attached to the conductor. In addition, when further overlapping winding is performed, the other variable thickness insulating tape further provided on the variable thickness insulating tape can be wound with the laminating tape side on the inner side and the adhesive layer on the inner side, thereby making the appearance of the insulating coating uniform and smooth. This has the effect of preventing the insulated wire from getting caught on a jig used during processing, such as when manufacturing a coil from the insulated wire, and suppresses the occurrence of scratches during processing. In order to facilitate stripping of the insulating coating, the variable thickness insulating tape that is first wrapped around the outer periphery of the conductor can be wrapped with the adhesive layer on the outside.

[0015] In the insulated wire according to the present invention, the variable thickness insulating tape is wound around the outer periphery of the conductor, and another variable thickness insulating tape or a constant thickness insulating tape is wound around the variable thickness insulating tape, so that the thick insulating coating and the thin insulating coating are repeated. According to the present invention, an insulated wire can be obtained in which a plurality of variable thickness insulating tapes are wound to make the thick insulating coating even thicker and thereby increase the dielectric strength voltage, or an insulated wire can be obtained in which a constant thickness insulating tape is further wound to make the thin insulating coating thicker and thereby adjust the space factor.

[0016] In the insulated wire according to the present invention, when another variable thickness insulating tape is wound on top of the variable thickness insulating tape, the thick region of the other variable thickness insulating tape is wound so as to overlap the already formed thick insulating coating. According to this invention, since the thick region of the other variable thickness insulating tape is wound so as to overlap the already formed thick insulating coating, the thick insulating coating can be made even thicker.

[0017] In the insulated wire according to the present invention, when another variable thickness insulating tape or a constant thickness insulating tape is wound on top of the variable thickness insulating tape, the other variable thickness insulating tape and the constant thickness insulating tape are wound in different winding directions from the variable thickness insulating tape. According to this invention, when a plurality of insulating tapes are wound in a layered manner, the insulating tapes are wound in different winding directions, so that the insulating coating thickness can be made uniform and the surface can be made smooth. This has the effect of preventing the insulated wire from getting caught on a jig used during processing, such as when manufacturing a coil from the insulated wire, and suppresses the occurrence of scratches during processing.

[0018] In the insulated wire according to the present invention, the thick insulating coating has tapered portions at both ends thereof, which can smoothly change the thick insulating coating into a thin insulating coating, and have the effect of preventing the insulated wire from getting caught on a jig used during processing, such as when manufacturing a coil from the insulated wire, and can suppress the occurrence of scratches during processing.

[0019] In the insulated wire according to the present invention, the tapered portion preferably has a taper ratio of 0.5 / 1000 to 150 / 1000. By setting the taper ratio within this range, an appropriate insulation thickness can be obtained, and good insulating properties can be exhibited.

[0020] In this case, the thick insulating coating and the thin insulating coating are formed by winding a variable thickness insulating tape having thick and thin regions at a predetermined interval around the outer periphery of the conductor, and the boundary between the thick and thin regions of the variable thickness insulating tape is formed obliquely with respect to the longitudinal direction of the variable thickness insulating tape. According to this invention, it is possible to reduce abrupt changes in the outer diameter of the insulated electric wire around which the boundary portion of the variable thickness insulating tape is wound. As a result, the amount of change in the outer diameter is reduced, and the surface can be made smooth. This has the effect of preventing the insulated electric wire from getting caught on a jig used during processing, such as when manufacturing a coil from the insulated electric wire, and suppresses the occurrence of scratches during processing.

[0021] In the insulated wire according to the present invention, when a winding angle of the variable thickness insulating tape with respect to the longitudinal direction of the conductor is θ1, an angle of a boundary line between the thick region and the thin region with respect to the longitudinal direction of the variable thickness insulating tape is θ2, and an angle between the boundary line of the variable thickness insulating tape and the longitudinal direction of the conductor is θ3, the variable thickness insulating tape is wound in a direction such that θ1 is in the range of 10° to 60°, θ2 is in the range of 10° to 90°, and θ2 is larger than θ3. It is particularly preferable that θ3 is 0°.

[0022] In the insulated wire according to the present invention, an extruded resin layer is further provided as an insulating outer covering.

[0023] (2) A coil according to the present invention is obtained by winding the insulated wire according to the present invention, and is characterized in that the insulated wire is composed of a portion provided with a thick insulating coating and a portion provided with a thin insulating coating, and the thick insulating coating and the thin insulating coating are provided repeatedly at any interval.

[0024] According to the present invention, since the insulated electric wire is obtained by winding the thick insulating coating and the thin insulating coating repeatedly provided at an arbitrary interval, it is possible to use an insulated electric wire with a thicker insulating coating in a portion where partial discharge is likely to occur or a portion where a high dielectric strength voltage is required. As a result, it is possible to increase the partial discharge inception voltage in a jumper portion, for example, or to obtain a coil with an increased dielectric strength voltage in a portion where a high dielectric strength voltage is required. Also, it is possible to use an insulated electric wire with a thinner insulating coating in a slot conductor portion or a portion where a high dielectric strength voltage is not required, for example, and it is possible to increase the space factor without deteriorating it.

[0025] In this coil, it is preferable that the insulating coating of the insulated electric wire is thick in the portion where the voltage is high and partial discharge is likely to occur, and is thin in the portion where the voltage is not high and partial discharge is unlikely to occur. According to this invention, since the insulating coating of the insulated electric wire is thick in the portion where partial discharge is likely to occur, it is possible to increase the partial discharge inception voltage, for example, at the jumper portion, and since the insulating coating of the portion where partial discharge is unlikely to occur is thin, it is possible to increase the space factor without deteriorating it. Since these portions are provided repeatedly at any interval, for example, when the coil is preferably applied as a coil for a three-phase induction motor, it is possible to use a thin insulating coating at the slot conductor portion of the motor and a thick insulating coating at the portion where a high voltage is applied to the jumper portion connecting the slot conductor portions of the motor.

[0026] (3) The variable thickness insulating tape according to the present invention is characterized in that it is made of an insulator and has repeated thin and thick portions. By wrapping the variable thickness insulating tape around the outer periphery of a conductor, it is possible to form an insulating coating consisting of thick and thin portions around the outer periphery of the conductor.

[0027] In the variable thickness insulating tape according to the present invention, the thickness of the thick portion is 1.5 to 8 times the thickness of the thin portion. Since the thickness of the thick portion of the variable thickness insulating tape is within the above range, the variable thickness insulating tape can be wound around the conductor with good work efficiency and can provide an insulating coating with a sufficient thickness difference.

[0028] In the variable thickness insulating tape according to the present invention, the thicker portion is colored. According to this invention, the thicker portion can be easily recognized when winding the variable thickness insulating tape. Furthermore, when the variable thickness insulating tape is wound around the outer periphery of a conductor, the thicker portion of the insulating coating formed around the outer periphery of the conductor can be made into a colored portion.

[0029] In the variable thickness insulating tape according to the present invention, the thin portion is made of a base tape, and the thick portion is made of the base tape and a lamination tape laminated onto one main surface of the base tape. According to this invention, a simple structure can be achieved that does not require complicated processes.

[0030] In the variable thickness insulating tape according to the present invention, the thin portion is formed by overlapping a base tape and a cover tape, and the thick portion is formed by a laminated tape sandwiched between the base tape and the cover tape and laminated onto one main surface of the base tape. According to this invention, a simple structure that does not require complicated processes can be obtained, and further, by using a cover tape, winding ability when winding the tape around the outer periphery of a conductor can be improved.

[0031] In the variable thickness insulating tape according to the present invention, the laminating tape is colored. According to this invention, the thick portion of the variable thickness insulating tape can be colored with a simple structure that does not require complicated processes.

[0032] In the variable thickness insulating tape according to the present invention, the base tape and the laminating tape are made of insulating materials having the same heat resistance temperature. According to this invention, the heat resistance temperature of the variable thickness insulating tape can be made uniform, which is preferable in terms of the heat resistance of the entire wire when used as an insulating coating for an insulated wire.

[0033] In the variable thickness insulating tape according to the present invention, the boundary between the thick and thin portions is formed obliquely with respect to the longitudinal direction of the variable thickness insulating tape. According to this invention, when the variable thickness insulating tape is wound around a conductor, it is possible to reduce abrupt changes in the outer diameter of the insulated electric wire around which the boundary portion where the thickness of the variable thickness insulating tape changes is wound. As a result, the amount of change in the outer diameter is reduced, and the surface can be made smooth.

[0034] The variable thickness insulating tape according to the present invention functions as an insulating coating provided around the outer periphery of a conductor that constitutes an insulated wire.

[0035] (4) The method for manufacturing a variable thickness insulating tape according to the present invention is a method for manufacturing a variable thickness insulating tape made of an insulator and having repeated thin and thick portions, and is characterized in that it is any one of the following (a) to (e). (A) A method in which a laminated base tape that will become the thick portion is temporarily adhered onto a base tape that will become the thin portion, and the laminated base tape is removed in a predetermined shape to form the remaining part of the laminated base tape into the thick portion; (A) a method of laminating a lamination tape formed into a predetermined shape to become the thick portion to a base tape to become the thin portion; (c) A method in which a bonding tape that is to become the thick portion and has been slit to a predetermined width is bonded to a base tape that is to become the thin portion and then cut, or a method in which the bonding tape is heat-pressed and cut at the same time; (E) A method in which a laminated base tape that will become the thick portion is temporarily adhered onto a process tape, the laminated base tape is removed in a predetermined shape to form the remaining portion of the laminated base tape into the thick portion, a base tape that will become the thin portion is laminated onto the second tape that will become the thick portion, and finally the process tape is removed.

[0036] According to this invention, it is possible to manufacture a variable thickness insulating tape that is composed of a base tape consisting of a thin portion and a laminated tape consisting of a thick portion that is laminated onto one main surface of the base tape via an adhesive layer.

[0037] The method for manufacturing a variable thickness insulating tape according to the present invention further includes a step of laminating a cover tape onto the laminating tape. According to this invention, a sandwich structure can be formed by having a cover tape covering the laminating tape with an adhesive layer interposed therebetween. Effect of the Invention

[0038] According to the present invention, it is possible to provide an insulated wire capable of increasing the partial discharge inception voltage, preventing deterioration of the insulator, and preventing a decrease in the space factor, and a motor coil made from the insulated wire. Also, according to the present invention, it is possible to provide a variable thickness insulating tape used for making an insulated wire composed of a thick insulating coating and a thin insulating coating, and a method for manufacturing the same. [Brief description of the drawings]

[0039] [Figure 1] FIG. 1 is a perspective view showing an example of an insulated wire according to the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing an example of a variable thickness insulating tape. [Diagram 3] 2 is a schematic diagram for explaining the structure of thick and thin regions that make up a variable thickness insulating tape. FIG. [Figure 4]These are examples of cross-sectional views of variable thickness insulating tapes, where (A) is a variable thickness insulating tape having a laminating tape provided on a base tape, and (B) is a variable thickness insulating tape having a laminating tape provided on a base tape and then a cover tape provided on top of that. [Diagram 5] 1 is a vertical cross-sectional view showing an insulating coating structure of a first embodiment. [Figure 6] FIG. 6 is a vertical cross-sectional view showing an insulating coating structure according to a second embodiment. [Figure 7] FIG. 11 is a vertical cross-sectional view showing an insulating coating structure according to a third embodiment. [Figure 8] FIG. 11 is a vertical cross-sectional view showing an insulating coating structure according to a fourth embodiment. [Figure 9] FIG. 1 is a diagram showing examples of insulating tape configurations, in which (A) is an example in which the boundary between the thick and thin regions is perpendicular to the longitudinal direction of the tape, and (B) is an example in which the boundary between the thick and thin regions is at a predetermined angle θ2 with respect to the longitudinal direction of the tape. [Figure 10] These are examples of the shape in which the tape shown in Figure 9(B) is wound around the conductor at a predetermined winding angle θ1, where (A) is an example of winding in a winding direction in which the angle θ3 between the boundary line of the tape and the longitudinal direction of the conductor is smaller than the boundary line angle θ2 of the tape, and (B) is an example of winding in a winding direction in which the angle θ3 between the boundary line of the tape and the longitudinal direction of the conductor is larger than the boundary line angle θ2 of the tape. [Figure 11] This is an example in which the tape shown in Figure 9(B) is wound around the conductor at a predetermined winding angle θ1, where the tape boundary angle θ2 is the same as the tape winding angle θ1, and the angle θ3 between the boundary line and the longitudinal direction of the conductor is 0°. [Figure 12] FIG. 1 shows external views of examples of lap winding configurations, where (A) is an example of half-lap winding of a variable thickness insulating tape, and (B) is an example of one-third lap winding of a variable thickness insulating tape that is overlap-wound. [Figure 13] FIG. 2 is a configuration development diagram of a coil for a three-phase induction motor. [Figure 14] FIG. 1 is a process diagram showing an example of a method for manufacturing a variable thickness insulating tape according to the present invention. [Figure 15]5A to 5C are process diagrams showing another example of a method for manufacturing a variable thickness insulating tape according to the present invention. [Figure 16] 5A to 5C are process diagrams showing yet another example of the method for manufacturing a variable thickness insulating tape according to the present invention. [Figure 17] 5A to 5C are process diagrams showing yet another example of the method for manufacturing a variable thickness insulating tape according to the present invention. [Figure 18] 5A to 5C are process diagrams showing yet another example of the method for manufacturing a variable thickness insulating tape according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] The insulated wire, coil, variable thickness insulating tape, and method of manufacturing the same according to the present invention will be described with reference to the drawings. Note that the present invention can be modified in various ways as long as it has the technical characteristics, and is not limited to the following description and the forms shown in the drawings.

[0041] [Insulated wire] 1 and 5 to 8, an insulated wire 10 according to the present invention is an insulated wire 10 having a conductor 1 and insulating coatings 2, 3 provided on the outer periphery of the conductor 1, and is characterized in that when wound into a coil, the insulated wire 10 is configured with a thick insulating coating 3 for a portion where the voltage becomes high and partial discharge is likely to occur, and a thin insulating coating 2 for a portion where the voltage does not become high and partial discharge is unlikely to occur, and the thick insulating coating 3 and the thin insulating coating 2 are provided repeatedly at arbitrary intervals. A coil 40 obtained by winding such an insulated wire 10 is configured such that the insulating coating 3 of the insulated wire 10 is thick in a portion where the voltage becomes high and partial discharge is likely to occur, and the insulating coating 2 of the insulated wire 10 is thin in a portion where the voltage does not become high and partial discharge is unlikely to occur, as shown in the developed coil configuration diagram of FIG.

[0042] In the insulated wire 10 according to the present invention, the insulating coating 3 of the insulated wire is thick in the portion where partial discharge is likely to occur, so that it is possible to increase the partial discharge inception voltage, for example, at the jumper portion, and the insulating coating 2 of the insulated wire is thin in the portion where partial discharge is unlikely to occur, so that it is possible to increase the space factor without deteriorating. Since these portions are provided repeatedly at arbitrary intervals, for example, when the insulated wire 10 is preferably applied as a coil 40 for a three-phase induction motor, it is possible to provide a thin insulating coating 2 at the slot conductor portion of the motor and a thick insulating coating 3 at the jumper portion where a high voltage is applied, which connects the slot conductor portions of the motor. As a result, it is possible to provide an insulated wire that can increase the partial discharge inception voltage, prevent deterioration of the insulator, and prevent a deterioration of the space factor, and a coil for a motor made from the insulated wire.

[0043] Each component will be described below.

[0044] (conductor) The conductor 1 is not particularly limited as long as it is applied as the central conductor of the insulated electric wire 10, particularly the insulated electric wire 10 for coils, and may be any type of conductor, regardless of the material or twisting configuration. For example, it may be composed of one element wire extending in the longitudinal direction, may be composed of several element wires twisted together, or may be composed as a Litz wire. The element wire is not particularly limited in type as long as it is a metal with good electrical conductivity, and preferred examples include metal conductors with good electrical conductivity such as copper wire, copper alloy wire, aluminum wire, aluminum alloy wire, and copper-aluminum composite wire, or those with a plating layer applied to the surface thereof. From the viewpoint of coil use, copper wire and copper alloy wire are particularly preferred. 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 preferred. Furthermore, the "conductor" and "element wire" in the present invention also include those covered with an enamel layer for insulation, oxidation prevention, etc. The cross-sectional shape of the element wire is not particularly limited, and the cross-sectional shape may be a wire material with a circular or approximately circular shape, or may be a rectangular shape.

[0045] The cross-sectional shape of the conductor 1 is not particularly limited, and may be circular (including elliptical) or rectangular. It is desirable that the cross-sectional size of the conductor 1 is as large as possible so that the electrical resistance (AC resistance, conductor resistance) is small so that the conductor can be preferably used for coils. For example, the outer diameter of a circular strand may be about 0.05 to 4 mm. In the case of a rectangular strand, the short side may be about 0.3 to 5 mm, and the long side may be about 0.5 to 10 mm. The cross-sectional size of the conductor 1 is appropriately selected depending on the application of the coil, but the smaller the cross-sectional size, the higher the adhesion and positioning accuracy of the insulating coatings 2 and 3 described below must be.

[0046] (insulation coating) As shown in Fig. 1, the insulating coatings 2 and 3 are provided on the outer circumference of the conductor 1. The insulating coating is composed of a thick insulating coating 3 for the portion where partial discharges are likely to occur due to high voltage when wound around a coil, and a thin insulating coating 2 for the portion where partial discharges are unlikely to occur because the voltage does not become high, and these are provided repeatedly at arbitrary intervals. The insulating coating 3 for the portion where partial discharges are likely to occur can increase the partial discharge inception voltage at, for example, a jumper portion, and the insulating coating 2 for the portion where partial discharges are unlikely to occur can be increased without deteriorating the space factor, for example.

[0047] The material of the insulating coatings 2 and 3 is not particularly limited, but for example, materials used in insulating tapes such as polyethylene resin, polyester resin (PET, PEN, etc.), polyimide resin, polyamide resin, polyamideimide resin, polystyrene resin, polyphenylene sulfide resin, PEEK (polyether ether ketone), etc. can be preferably used. Conductive materials such as aluminum foil, copper foil, or metal foils obtained by plating them with tin, nickel, gold, etc. may also be used. Among these resin materials, fluorine-based resins with low dielectric constants such as PFA, ETFE, FEP, etc., which are used as dielectric materials, or resins such as polyphenylene ether resin, polyolefin resin such as polypropylene, polyester resin, polyacrylic resin, etc. may also be used.

[0048] The thin insulating coating 2 preferably has a thickness in the range of 2 to 500 μm, and the thick insulating coating 3 is thicker than the thin insulating coating 2 and preferably has a thickness in the range of 4 to 1000 μm. The thicknesses of the thin insulating coating 2 and the thick insulating coating 3 are set according to the characteristics of the coil in which the insulated electric wire 10 is used. The thin insulating coating 2 is preferably thicker than the thin insulating coating 2 so that the thickness satisfies at least the required dielectric strength voltage, and is usually preferably 2 μm or more. On the other hand, the thick insulating coating 3 is preferably thicker than the thin insulating coating 2 so that the thickness satisfies at least the required dielectric strength voltage, and is usually preferably 4 μm or more. The thickness of the thick insulating coating 3 is 1.5 to 8 times, and preferably 2 to 7 times, the thickness of the thin insulating coating 2.

[0049] It is preferable that the insulating coatings 2 and 3 have different visibility from each other. Specifically, the visibility can be made different by changing the color, pattern, unevenness, etc. of the insulating coatings 2 and 3. By making the insulating coatings 2 and 3 have different visibility from each other, it becomes possible to distinguish the thin insulating coating 2 from the thick insulating coating 3. This allows an operator or a discrimination sensor to distinguish the thin insulating coating 2 from the thick insulating coating 3 during coil production, making the coil production process easier. Note that a form in which the color of the thick insulating coating 3 is darker than the color of the thin insulating coating 2, or a form in which the thick insulating coating 3 is colored and the thin insulating coating 2 is not colored, is preferable from the viewpoint of ease of the manufacturing process when using a thickness-changing insulating tape 20 described later.

[0050] As shown in Fig. 1 (A) and (B), the thin insulating coating 2 and the main body 3b of the thick insulating coating 3 have a tapered portion 3a between them. The tapered portion 3a is formed so that its thickness increases from the boundary with the thin insulating coating 2 to the boundary with the main body 3b. The thick insulating coating 3 has the main body 3b, and has tapered portions 3a at both ends of the main body 3b in the longitudinal direction of the insulated electric wire 10. The thick insulating coating 3 has the tapered portions 3a, which reduces the amount of change in the outer diameter of the insulated electric wire 10 and allows the insulating coating thickness to change smoothly. This has the effect of preventing the insulated electric wire 10 from getting caught on a jig used during processing, such as when manufacturing a coil using the insulated electric wire 10, and can suppress the occurrence of scratches during processing.

[0051] 1(B) is an insulated electric wire 10 in which the longitudinal length of tapered portion 3a is longer than that of the insulated electric wire 10 in the embodiment shown in Fig. 1(A). By forming tapered portion 3a longer in this manner, the amount of change in the outer diameter of insulated electric wire 10 can be reduced, and the thickness of the insulating coating can be changed more smoothly.

[0052] The taper ratio of the tapered portion 3a (difference in taper diameter / axial length of the tapered portion) is preferably in the range of 0.5 / 1000 to 150 / 1000. If the taper ratio is smaller than 0.5 / 1000, the axial length of the tapered portion 3a is too long, which may make it difficult to obtain an appropriate insulation thickness. If the taper ratio is larger than 150 / 1000, the amount of change in the outer diameter from the thin insulating coating 2 to the thick insulating coating 3 is large, which may cause problems with the insulation characteristics. The taper ratio is more preferably 1.0 / 1000 to 100 / 1000.

[0053] (Variable thickness insulating tape) As shown in FIG. 2, the variable thickness insulating tape 20 has a tape portion 21 (also called the thin portion 21) that becomes the thin region B and a tape portion 22 (also called the thick portion 22) that becomes the thick region A at a predetermined interval. In other words, the thin portion 21 and the thick portion 22 are repeated. Here, "repeated" means that the thin portion 21 and the thick portion 22 are alternated. "Alternate" may mean that they are repeated at a constant interval (pitch) as shown in FIG. 3, or may mean that they are repeated at an irregular interval that is not constant. The "predetermined interval" may be within a range of several mm to several m, and can be set arbitrarily depending on the use of the insulated wire.

[0054] FIG. 3 is a schematic diagram for explaining the structure of the thin portion 21 and the thick portion 22. As shown in FIG. 3, the repeating form is not particularly limited and can be various forms. For example, the example of FIG. 3(A) is an example in which the intervals P1, P2, P3 (also called distance) between the thick portions 22a, 22b, 22c are not constant, and the interval P1 between the thick portion 22a and the thick portion 22b may be set longer than the interval P2 between the thick portion 22b and the thick portion 22c and the interval P3 between the thick portion 22c and the thick portion 22a. In this case, the longitudinal lengths L1, L2, L3 of the thick portions 22a, 22b, 22c are constant. Moreover, the example of FIG. 3(B) is an example in which the longitudinal lengths of the thick portions 22a, 22b, 22c are not constant, and the longitudinal length L1 of the thick portion 22a may be set longer than the longitudinal length L2 of the other thick portions 22b. At this time, the distance P1 between the thick portion 22a and the thick portion 22b and the distance P2 between the thick portion 22b and the thick portion 22c are constant.

[0055] The length of the thick portion 22 in the longitudinal direction and / or the interval between the thick portions 22 can be set arbitrarily as shown in FIG. 3, and the interval P1 between the thick portion 22a and the thick portion 22b can be different from the interval P2 between the thick portion 22b and the thick portion 22c and / or the interval P3 between the thick portion 22c and the thick portion 22a, and further, the lengths L1, L2, and L3 in the longitudinal direction of the thick portions 22a, 22b, and 22c can also be different lengths. As a result, for example, it is possible to adjust the position where the insulating coating is thickened to increase the insulating property, and the degree of freedom in design can be improved. Note that the thick portion 2 may be provided as an oblique line shape as shown in FIG. 9(B), and in such a case, the intervals P1 and P2 can be the interval between the thick portions 22 in the longitudinal direction X of the tape.

[0056] By wrapping such a variable thickness insulating tape 20 around the conductor 1 shown in Fig. 1, insulating coatings 2 and 3 are formed around the conductor 1, resulting in an insulated wire 10 in which thin insulating coatings 2 and thick insulating coatings 3 are repeatedly provided at arbitrary intervals. In more detail, by wrapping a tape portion 21 shown in Fig. 2 around the conductor 1, the thin insulating coating 2 is formed, and by wrapping a tape portion 22 around the conductor 1, the thick insulating coating 3 is formed.

[0057] Regarding the thickness, the thickness of the tape portion 22 that becomes the thick region A is preferably 1.5 times or more and 8 times or less than the thickness of the tape portion 21 that becomes the thin region B. If the thickness of the tape portion 22 is less than 1.5 times the thickness of the tape portion 21, the thickness of the thick insulating coating 3 formed by winding the tape portion 22 around the outer circumference of the conductor 1 may not be thick enough for the thin insulating coating 2 formed by winding the tape portion 21 around the outer circumference of the conductor 1. If the thickness of the tape portion 22 is more than 8 times the thickness of the tape portion 21, the thickness-changing insulating tape 20 is likely to bend or wrinkle when the tape portion 22 is wound around the outer circumference of the conductor 1, and the appearance of the wound tape may be uneven. It is more preferable that the thickness of the tape portion 22 that becomes the thick region A is 2 times or more and 7 times or less than the thickness of the tape portion 21 that becomes the thin region B.

[0058] The distance between the tape portion 21 that will become the thin region B and the tape portion 22 that will become the thick region A is designed based on how far apart the thin insulating coating 2 and the thick insulating coating 3 must be when making a coil with the insulated wire 10 formed by winding the variable thickness insulating tape 20 around the outer periphery of the conductor 1. The design takes into consideration the width, winding pitch, laps, etc. of the variable thickness insulating tape 20, and an example is where the tape portions 22, for example, 60 to 80 mm long are spaced 40 to 60 mm apart in the longitudinal direction, as shown in FIG.

[0059] As shown in Figure 4(A), the variable thickness insulating tape 20 is composed of a base tape 23 having two main surfaces F1, F2, and a lamination tape 24 bonded to one of the main surfaces F1 of the base tape 23 via an adhesive layer 25, and has a simple structure that does not require complex processes.

[0060] The base tape 23 constitutes the tape portion 21 which becomes the thin region B, and the base tape 23 and the laminating tape 24 constitute the tape portion 22 which becomes the thick region A. By wrapping the variable thickness insulating tape 20 around the outer periphery of the conductor 1, the portion wrapped with the tape portion 21 forms the thin insulating coating 2, and the portion wrapped with the tape portion 22 forms the thick insulating coating 3. No adhesive layer is provided on the other main surface F2 of the base tape 23.

[0061] Meanwhile, an adhesive layer 26 is provided on the laminating tape 24. Also, an adhesive layer 26 is provided on one main surface F1 of the base tape 23, which is the laminating tape surface side of the tape portion 21 to which the laminating tape 24 is not attached. In this variable thickness insulating tape 20, the adhesive layer 26 is provided on one main surface F1 of the base tape 23, which is the laminating tape surface side of the tape portion 21, and on the laminating tape 24, so that the adhesive layer 26 side is wound around the outer periphery of the conductor 1 with the conductor side (inner side).

[0062] Although not shown, the adhesive layer 26 may be provided on the other main surface F2, which is the flat surface side of the base tape 23, and not provided on the surface side S1 of the laminating tape 24. In this case, the flat surface side S2 of the base tape 23, i.e., the other main surface F2 of the base tape 23, is wound around the conductor with the conductor side being the adhesive side.

[0063] 4(B), the variable thickness insulating tape 20 has a so-called sandwich structure that is made up of a base tape 23, a lamination tape 24 that is laminated onto one main surface F1 of the base tape 23 via an adhesive layer 25, and a cover tape 27 that covers the entire lamination tape 24 via an adhesive layer 25a. With this structure, the variable thickness insulating tape 20 can be produced with a simple structure that does not require complex processes, and further, the use of the cover tape 27 can improve the ease of winding the tape around the conductor 1.

[0064] The base tape 23 and the cover tape 27 form the tape portion 21 which is the thin region B, and the base tape 23, the laminating tape 24, and the cover tape 27 form the tape portion 22 which is the thick region A. An adhesive layer 26 is provided on the other main surface F2 of the flat surface side S2 of the base tape 23. On the other hand, no adhesive layer is provided on the cover tape 27. In this thickness-changing insulating tape 20, the adhesive layer 26 is provided on the other main surface F2 of the flat surface side S2 of the base tape 23, so that the adhesive layer 26 side is wound around the outer periphery of the conductor 1 as the conductor side (inner side). Although not shown, the adhesive layer 26 may be provided on the cover tape 27, and not provided on the flat surface side S2 of the base tape 23, that is, on the other main surface F2 of the base tape 23. In this case, the laminating tape is wound around the conductor as the surface side S1 of the laminating tape is the conductor side.

[0065] As shown in Fig. 4(A)(B), the adhesive layer 26 is provided on either the surface side S1 of the laminating tape or the flat side S2 of the base tape. The variable thickness insulating tape 20 that is first wrapped around the outer circumference of the conductor 1 is wound with the flat side S2 of the base tape facing inward (conductor side) or outward, and the adhesive layer 26 facing inward, and another variable thickness insulating tape 20 provided on top of it is wound with the surface side S1 of the laminating tape facing inward and the adhesive layer 26 facing inward. This allows the flat side S2 of the base tape to be firmly attached to the conductor. When further overlapping and winding, the other variable thickness insulating tape 20 provided on the variable thickness insulating tape 20 is wound with the surface side S1 of the laminating tape facing inward (conductor side) and the adhesive layer 26 provided on it facing inward, thereby making the appearance of the insulating coating uniform and smooth. This has the effect of preventing the insulated wire 10 from getting caught on a jig used during processing, such as when manufacturing a coil from the insulated wire 10, and makes it possible to suppress the occurrence of scratches during processing.

[0066] The variable thickness insulating tape 20 can also be wrapped with the adhesive layer 26 on the outside, opposite the conductor side. In this case, since it is not firmly attached to the conductor 1, the insulating coatings 2 and 3 of the variable thickness insulating tape 20 are easily peeled off during end processing.

[0067] The base tape 23 and the laminating tape 24 are preferably made of insulating materials with the same level of heat resistance. If the base tape 23 and the laminating tape 24 have the same level of heat resistance, the insulating coatings 2 and 3 also have the same heat resistance. This makes the heat resistance temperature of the variable thickness insulating tape 20 uniform, so that the heat resistance temperatures of the insulating coatings 2 and 3 are the same or nearly the same, which is preferable in terms of the heat resistance of the entire insulated wire. The same level of heat resistance refers to the same "Upper limit of operating temperature for insulation materials used in electrical appliances, Appendix 11" as stipulated in the Electrical Appliance and Material Safety Act established by the Ministry of Economy, Trade and Industry of Japan.

[0068] The adhesive layers 25, 26 are preferably made of a thermoplastic resin such as acrylic, polyester, urethane, polyimide, PVC, EVA, etc., or a thermosetting resin such as an epoxy resin, bismuth imide, etc. The thickness of the adhesive layers 25, 26 is preferably within a range of, for example, 0.2 μm or more and 50 μm or less, and more preferably within a range of 0.5 μm or more and 40 μm or less.

[0069] The adhesive layers 25 and 26 can be formed by dissolving the resin in an organic solvent and applying an adhesive paint to a predetermined thickness (e.g., 2 μm) using a coating device such as a gravure printer. Such an adhesive layer may be provided not only between the base tape 23 and the laminating tape 24 (adhesive layer 25), but also between the base tape 23 and the laminating tape 24 (adhesive layer 25a) and the cover tape 27, or on one side of the thickness-changing insulating tape 20 (S1 or S2) as adhesive layer 26.

[0070] The thicknesses of the thin insulating coating 2 and the thick insulating coating 3 are designed as desired depending on the degree of overlap (wrap) of each of the tape portion 21 and the tape portion 22 wound around the outer circumference of the conductor 1, and the thickness of the tape wound on the outside of the tape portion 21 and the tape portion 22. For example, when the tape portion 21 is wound with 1 / 2 wrap, the tape portion 21 has a double structure as shown in Figs. 5 to 7, so it is generally preferable that the thickness of the tape portion 21 is 1 / 2 of the thickness of the thin insulating coating 2 to be obtained. When the tape portion 21 is wound with 2 / 3 wrap, the tape portion 21 has a triple structure as shown in Fig. 8, so it is generally preferable that the thickness of the tape portion 21 is 1 / 3 of the thickness of the thin insulating coating 2 to be obtained. In addition, when the adhesive layer 26 is provided on the other main surface F2, which is one side (flat surface) S2 of the base tape 23, to form the tape portion 21, the thickness including the adhesive layer 26 is the thickness of the tape portion 21, so the thickness of the base tape 23 is designed taking into account the thickness of the adhesive layer 25. In addition, as shown in Figs. 6 to 8, when the constant thickness insulating tape 30 or the variable thickness insulating tape 20 is wound further outside the tape portion 21 and the tape portion 22, the thickness of the tape portion 21 that becomes the thin insulating coating 2 of the constant thickness insulating tape 30 or the variable thickness insulating tape 20 wound on the outside and the thickness of the adhesive layer that adheres the tape portion 21 that becomes the thin insulating coating 2 of the constant thickness insulating tape 30 or the variable thickness insulating tape 20 are added to the thickness of the tape portion 21 to determine the thickness of the thin insulating coating 2. In other words, when the constant thickness insulating tape 30 or the variable thickness insulating tape 20 is wound further outside the tape portion 21 and the tape portion 22, in the tape portion 21 which becomes the thin insulating coating 2, the thickness of the constant thickness insulating tape 30 or the variable thickness insulating tape 20 wound on the outside is added to the thickness of the adhesive layer that adheres the constant thickness insulating tape 30 or the variable thickness insulating tape 20 to the tape portion 21, which becomes the thin insulating coating 2, to become the thickness of the thin insulating coating 2.

[0071] Since the tape portion 22 is also wound around the outer circumference of the conductor 1, the thickness of the tape portion 22 is the sum of the thickness of the base tape 23, the thickness of the laminating tape 24, and the thickness of the adhesive layer 25 provided therebetween, and is designed according to the degree of overlap of the tape portion 22. For example, when the tape portion 22 is wound with 1 / 2 wrap, the tape portion 22 has a double structure as shown in Figs. 5 to 7, so it is generally preferable that the thickness of the tape portion 22 is 1 / 2 of the thickness of the thick insulating coating 3 to be obtained. Furthermore, when the tape portion 22 is wound with 2 / 3 wrap, the tape portion 22 has a triple structure as shown in Fig. 8, so it is generally preferable that the thickness of the tape portion 22 is 1 / 3 of the thickness of the thin insulating coating 3 to be obtained. 6 to 8, when the constant thickness insulating tape 30 or the variable thickness insulating tape 20 is wound further outside the tape portion 21 and the tape portion 22, the thickness of the tape portion 22 that becomes the thick insulating coating 3 of the constant thickness insulating tape 30 or the variable thickness insulating tape 20 wound on the outside and the thickness of the adhesive layer that adheres the tape portion 22 that becomes the thick insulating coating 3 of the constant thickness insulating tape 30 or the variable thickness insulating tape 20 are added to the thickness of the tape portion 22 to determine the thickness of the thick insulating coating 3. In other words, when the constant thickness insulating tape 30 or the variable thickness insulating tape 20 is wound further outside the tape portion 21 and the tape portion 22, the thickness of the constant thickness insulating tape 30 or the variable thickness insulating tape 20 that is wound on the outside of the tape portion 21 and the tape portion 22, in the tape portion 22 that becomes the thick insulating coating 3, the thickness of the constant thickness insulating tape 30 or the variable thickness insulating tape 20 that is wound on the outside and the thickness of the adhesive layer that adheres the constant thickness insulating tape 30 or the variable thickness insulating tape 20 are added to the thickness of the thick insulating coating 3.

[0072] In addition, when an adhesive layer 26 is provided on either the surface side S1 of the laminating tape 24 or one surface side (flat side S2) of the base tape 23 to form the tape portion 22, the thickness including the adhesive layer 26 becomes the thickness of the tape portion 22, so the thickness of the tape portion 22, i.e., the thickness of the base tape 23, the thickness of the laminating tape 24, and the thickness of the adhesive layer 25 provided between them, will be designed taking into account the thickness of the adhesive layer 26.

[0073] The adhesive layer 26 is preferably provided on one of the surfaces (S1 or S2) of the thickness varying insulating tape 20. When the adhesive layer 26 is provided on the other main surface F2, which is the flat side S2 of the base tape, the surface side S2 can be adhered to the outer periphery of the conductor 1. When the adhesive layer 26 is provided on the laminating tape surface side S1, the surface side S1 can be adhered to the outer periphery of the conductor 1. It is possible to arbitrarily select which surface S1 or S2 is wound on the conductor side, but it is preferable that, for example, as shown in FIG. 7, the thickness varying insulating tape 20 wound first has the adhesive layer 26 provided on the other main surface F2, which is the flat side S2 of the base tape, and is wound with the flat side S2 of the base tape on the conductor side, and the thickness varying insulating tape 20 wound on top of it has the adhesive layer 26 provided on the laminating tape surface side S1, and is wound with the laminating tape surface side S1 on the conductor side. By doing this, the flat side S2 of the base tape can be adhered to the conductor 1, and even when the tapes are overlapped and wound, each of the thickness-varying insulating tapes 20 can be adhered, and the appearance of the insulating coating can be made uniform and smooth.

[0074] The variable thickness insulating tape 20 may be wound with the adhesive layer 26 facing outward, away from the conductor. In this case, the variable thickness insulating tape 20 is not firmly attached to the conductor 1, so that the insulating coatings 2 and 3 of the variable thickness insulating tape 20 are easily peeled off during end processing.

[0075] The variable thickness insulating tape 20 preferably has a predetermined width according to the diameter of the conductor 1 so that it can be easily wound around the conductor 1. The width is not particularly limited, but can be about 2 to 15 times the diameter of the conductor 1. A large-area sheet prepared for the variable thickness insulating tape can be slit to the predetermined width. This makes it possible to obtain a variable thickness insulating tape 20 for electric wires that is easy to wind and is particularly suitable for the insulated electric wire 10 for coils.

[0076] The thickness-changing insulating tape 20 can be produced by various methods exemplified in Figs. 14 to 17 described later, and is not particularly limited. For example, (1) a tape of the same size may be laminated on a base tape 23, and then the tape in the portion to be the thin insulating coating 2 is removed, and the remaining portion may be produced as a laminated tape 24. The tape may be removed by making a cut in the tape and peeling it off from the cut. Alternatively, (2) a laminated tape 24 of a predetermined length may be laminated on a base tape 23. Alternatively, (3) a tape of the same size may be laminated on a release tape, and then the tape in the portion to be the thin insulating coating 2 is removed, and the remaining portion may be produced as the laminated tape 24, and the base tape 23 may be laminated on the laminated tape 24, and finally the release tape may be removed.

[0077] Here, a configuration for achieving different visibility by changing the colors of the insulating coatings 2 and 3 will be described.

[0078] The thin insulating coating 2 is mainly composed of tape portion 21 which corresponds to thin region B in Fig. 2, and the thick insulating coating 3 is mainly composed of tape portion 22 which corresponds to thick region A in Fig. 2. Therefore, the visibility of tape portion 22 which mainly constitutes thick insulating coating 3 may be made different from the visibility of tape portion 21 which mainly constitutes thin insulating coating 2. Here, an embodiment in which the color of thick insulating coating 3 is darker than the color of thin insulating coating 2, or thick insulating coating 3 is colored and thin insulating coating 2 is not colored, is exemplified.

[0079] By coloring the tape portion 22 that becomes the thick region A, it is possible to color the thick insulating coating 3 that is mainly constituted by the tape portion 22. Specifically, in order to color the tape portion 22 with a simple structure that does not require complicated processes, it is sufficient to color either the adhesive layer 25 or the laminating tape 24, or both. The adhesive layer 25 and the laminating tape 24 can be colored using coloring materials such as red, blue, green, yellow, and orange, and red is preferable to improve the distinguishability. The coloring material may be a pigment or a dye. At this time, the tape portion 21 that becomes the thin region B is not colored, so that the thin insulating coating 2 that is mainly constituted by the tape portion 21 is in an uncolored state.

[0080] As described above, by making the tape portion 21 and the tape portion 22 different in color, it is possible to make the visibility of the insulating coatings 2, 3 provided on the outer periphery of the conductor 1 different as shown in Figs. 5 to 7. Specifically, since the thick insulating coating 3 is mainly composed of the tape portion 22, the thick insulating coating 3 is colored by coloring the tape portion 22. Also, since the thin insulating coating 2 is mainly composed of the tape portion 21, the insulating coating 2 can be formed to have a different color from the insulating coating 3 by not coloring the tape portion 21. This makes it possible to distinguish the thin insulating coating 2 from the thick insulating coating 3, and the thin insulating coating 2 and the thick insulating coating 3 can be distinguished by an operator, a discrimination sensor, or the like during coil production, making the coil production process easier.

[0081] (Constant thickness insulating tape) 6 and 8, the constant thickness insulating tape 30 is a tape of constant thickness that is wound, preferably in the opposite direction, on top of the variable thickness insulating tape 20, and a so-called resin tape with an adhesive layer is used. By wrapping this constant thickness insulating tape 30 around the outer periphery of the variable thickness insulating tape 20, the appearance of the insulating coating is made uniform and smooth, and the variable thickness insulating tape 20 is covered and protected. The constant thickness insulating tape 30 is wound with the adhesive layer side facing the variable thickness insulating tape 20.

[0082] The material of the constant thickness insulating tape 30 is preferably the same as that of the base tape 23 constituting the variable thickness insulating tape 20 described above. The thickness of the constant thickness insulating tape 30 is not particularly limited as long as it is thick enough to ensure the necessary dielectric strength voltage for the tape portion 21 and the tape portion 22 after the tape is wound. For example, it may be about 0.002 to 0.1 mm.

[0083] The adhesive layer constituting the constant thickness insulating tape 30 is provided on one side of the constant thickness insulating tape 30. The material of the adhesive layer can be the same as that of the adhesive layers 25, 26 constituting the variable thickness insulating tape 20 described above. The constant thickness insulating tape 30 is wound horizontally with the adhesive layer side facing inward (the side of the variable thickness insulating tape), and is bonded by heating or the like during or after the tape is wound. In this way, the constant thickness insulating tape 30 can be bonded to the variable thickness insulating tape 20 located underneath. The thickness of the adhesive layer is not particularly limited, and can be, for example, about 0.001 to 0.05 mm. When the tape portion 21 and the tape portion 22 are made to have different colors, it is preferable to use a colorless transparent or semi-transparent constant thickness insulating tape 30.

[0084] (Wrapping angle and wrapping shape) Next, the winding angle and winding form will be described with reference to Figs. 9 to 11. Fig. 9 is a configuration diagram showing an example of a variable thickness insulating tape 20. Fig. 9(A) shows an example in which a boundary line 19 between the tape portion 22 that becomes the thick region A and the tape portion 21 that becomes the thin region B is perpendicular to the longitudinal direction X of the variable thickness insulating tape 20, and Fig. 9(B) shows an example in which the boundary line 19 between the tape portion 22 and the tape portion 21 forms a predetermined angle θ2 with respect to the longitudinal direction X of the variable thickness insulating tape 20. In this way, the angle θ2 may be a right angle with respect to the longitudinal direction X, or may be an angle smaller than this (i.e., an angle when the boundary line 19 between the tape portion 22 that becomes the thick region A and the tape portion 21 that becomes the thin region B is formed so as to be oblique with respect to the longitudinal direction X of the variable thickness insulating tape 20).

[0085] When the angle θ2 is a right angle, the portion where the thin insulating coating 2 changes to the thick insulating coating 3 becomes a short tapered portion 3a, as shown in Fig. 1(A), and a slight step in the change in diameter occurs. On the other hand, when the angle θ2 is less than 90°, the portion where the thin insulating coating 2 changes to the thick insulating coating 3 becomes a long tapered portion 3a, as shown in Fig. 1(B), and as the angle θ2 becomes smaller, the change in diameter becomes smaller, the taper becomes gentler, and the step is eliminated. Note that if the angle θ2 is too acute, it becomes difficult to manufacture the thickness-changing insulating tape 20 itself, so the angle θ2 is preferably in the range of about 10° to 90°, and more preferably in the range of 15° to 60°.

[0086] Fig. 10 shows an example in which the variable thickness insulating tape 20 shown in Fig. 9(B) is wound around the conductor 1 at a predetermined winding angle θ1. Fig. 10(A) shows an example in which the winding direction is such that the angle θ3 between the boundary line 19 of the variable thickness insulating tape 20 and the longitudinal direction X of the conductor 1 is smaller than the angle θ2 of the boundary line 19 of the variable thickness insulating tape 20. On the other hand, Fig. 10(B) shows an example in which the winding direction is such that the angle θ3 between the boundary line 19 of the variable thickness insulating tape 20 and the longitudinal direction X of the conductor 1 is larger than the angle θ2 of the boundary line 19 of the variable thickness insulating tape 20. Note that θ1 is the angle between the longitudinal direction X of the conductor 1 and the longitudinal direction of the variable thickness insulating tape 20.

[0087] In the example shown in FIG. 10, when the thickness varying insulating tape 20 is wound in a direction such that θ2>θ3 as shown in FIG. 10(A), the outer diameter of the insulated wire 10 around the boundary line 19 of the thickness varying insulating tape 20 can be reduced from abruptly changing, compared to when the thickness varying insulating tape 20 is wound in a direction such that θ2<θ3 as shown in FIG. 10(B). As a result, the amount of change in the outer diameter is reduced, and the change in the coating thickness can be smoothed. In particular, when the thickness varying insulating tape 20 having a large change in thickness is used, it is advantageous in that the sudden change in the outer diameter of the insulated wire 10 can be reduced. In the example shown in FIG. 10, for example, when θ1 is 20° and θ2 is 45°, θ3 is about 25° in FIG. 10(A), and θ3 is about 65° in FIG. 10(B). When θ3 is 25°, the thickness change in the longitudinal direction X changes more along the boundary line 19 than when θ3 is 65°, so that it can be changed gradually. As a result, the sudden change in the outer diameter can be reduced, and the change in the outer diameter can be smoothed. The winding angle θ1 is preferably in the range of 10° to 60°, and more preferably in the range of 15° to 40°.

[0088] As shown in FIG. 11, the angle θ3 is most preferably 0°. That is, when the thickness-changing insulating tape 20 shown in FIG. 9(B) is wound around the conductor 1 at a predetermined winding angle θ1, the angle θ2 of the boundary line 19 of the thickness-changing insulating tape 20 and the winding angle θ1 of the thickness-changing insulating tape 20 are made the same, so that the angle θ3 between the boundary line 19 and the longitudinal direction X of the conductor 1 can be made 0°. The thickness of the insulating coating of the insulated electric wire 10 after the thickness-changing insulating tape 20 is wound varies along the boundary line 19. This minimizes the change in the outer diameter of the insulated electric wire 10 in the longitudinal direction X, so that the step due to the change in the outer diameter can be reduced and the change in the outer diameter can be made smoother. Specifically, the form shown in FIG. 1(B) is more preferable than the form shown in FIG. 1(A). As shown in FIG. 10 and FIG. 11, when the tape shown in FIG. 9 is wound around the conductor, the tape width and / or angles θ1 to θ3 of the thickness-changing insulating tape 20 used can be adjusted to appropriately set the taper ratio.

[0089] (First embodiment) The insulated wire 10A of the first embodiment shown in Fig. 5 has a configuration in which a variable thickness insulating tape 20 is wound around the outer circumference of a conductor 1 in a 1 / 2 wrap, and a thin insulating coating 2 and a thick insulating coating 3 are alternately arranged. Fig. 12(A) is an external view of the insulated wire 10A in which the variable thickness insulating tape 20 is wound in a 1 / 2 wrap. In the figure, the solid lines indicate the edges of the variable thickness insulating tape 20, and the dotted lines indicate steps within the same tape of the variable thickness insulating tape 20.

[0090] Tape portion 21 and tape portion 22 of variable thickness insulating tape 20 are wound around conductor 1 to form thin insulating coating 2 and thick insulating coating 3. At this time, as shown in Figure 5, a slight step is generated where the edges of variable thickness insulating tape 20 change over.

[0091] In such a configuration, by coloring the tape portion 22 that constitutes the thick insulating coating 3, the portion of the insulating coating 3 in Figure 12 (A) can be colored and the portion of the insulating coating 2 can be left uncolored, which makes it possible to differentiate the visibility of the insulating coatings 2, 3 and makes it easy to distinguish between the portion of the thick insulating coating 3 and the portion of the thin insulating coating 2.

[0092] Second embodiment In the insulated wire 10B of the second embodiment shown in FIG. 6, a variable thickness insulating tape 20 is wound around the outer circumference of a conductor 1 with 1 / 2 lap, and a constant thickness insulating tape 30 is further wound around the outer circumference of the variable thickness insulating tape 20 with 1 / 3 lap, so that a thin insulating coating 2 and a thick insulating coating 3 are repeated. The winding direction of the variable thickness insulating tape 20 and the winding direction of the constant thickness insulating tape 30 may be the same or opposite, but opposite directions are preferable. When the winding directions are opposite, the insulating coating thickness can be made uniform and smooth. Note that reference numeral 31 denotes a lapped portion, and reference numeral 32 denotes a non-lapped portion. This has the effect of preventing the insulated wire from being caught on a jig used during processing, such as when manufacturing a coil from the insulated wire, and can suppress the occurrence of scratches during processing. Note that FIG. 12(B) is an external view of an insulated wire 10B in a form in which a constant thickness insulating tape 30 is wound around the outermost layer with 1 / 3 lap. In the figure, solid lines indicate edges of the uniform thickness insulating tape 30, and dotted lines indicate steps within the same uniform thickness insulating tape 30.

[0093] The constant thickness insulating tape 30 is wound around the outer circumference of the variable thickness insulating tape 20 to form the thin insulating coating 2 and the thick insulating coating 3. At this time, as shown in FIG. 6, the constant thickness insulating tape 30 is affected by the step between the tape portion 21 and the tape portion 22 of the variable thickness insulating tape 20 in the lower layer, and a step occurs between the lap portion 31 and the non-lap portion 32. In this configuration, by coloring the tape portion 22 constituting the thick insulating coating 3 and using a colorless transparent or semi-transparent constant thickness insulating tape 30, the insulating coating 3 portion in FIG. 12(B) can be colored and the insulating coating 2 portion can be uncolored. This allows the visibility of the insulating coatings 2 and 3 to be different, and the thick insulating coating 3 portion and the thin insulating coating 2 portion can be easily distinguished.

[0094] Third embodiment In the insulated wire 10C of the third embodiment shown in FIG. 7, a variable thickness insulating tape 20A is wound around the outer circumference of the conductor 1 with 1 / 2 wrap, and another variable thickness insulating tape 20B is wound around the outer circumference of the variable thickness insulating tape 20A with 1 / 3 wrap, so that the thick insulating coating 3 and the thin insulating coating 2 are repeated. In this case, as shown in FIG. 7, the thick region A of the other variable thickness insulating tape 20B is wound so as to overlap the already formed thick insulating coating 3. In this way, the thick insulating coating 3 can be made even thicker. As in the third embodiment, a plurality of variable thickness insulating tapes 20 (20A, 20B) are wound to make the thick insulating coating 3 even thicker, and an insulated wire 10 with an increased dielectric strength can be obtained.

[0095] Although the thick insulating coating 3 is mainly made up of the tape portion 22 of the variable thickness insulating tape 20, it may also be partially made up of the tape portion 21 of the variable thickness insulating tape 20 (20B), as in the portion α shown in Fig. 7. In other words, the thick insulating coating 3 does not have to be made up only of the tape portion 22 of the variable thickness insulating tape 20, and may also partially include the tape portion 21. Similarly, the thin insulating coating 2 does not have to be made up only of the tape portion 21 of the variable thickness insulating tape 20, and may also partially include the tape portion 22.

[0096] (Fourth embodiment) In the insulated wire 10D of the fourth embodiment shown in FIG. 8, the variable thickness insulating tape 20 is wound around the outer circumference of the conductor 1 with 2 / 3 laps, and the constant thickness insulating tape 30 is further wound around the outer circumference of the variable thickness insulating tape 20 with 1 / 3 laps, so that the thin insulating coating 2 and the thick insulating coating 3 are repeated. The variable thickness insulating tape 20 is wound with 2 / 3 laps, so that the insulating coating 3 is formed by overlapping and winding in three layers. In this way, a thicker insulating coating 3 can be formed. The overlapping winding can be increased to four layers or more, but it is preferable that the overlapping winding is three layers or less because it is possible to prevent loosening and misalignment caused by the thick insulating coating 3, particularly, if the overlapping winding is up to a maximum of 2 / 3 laps, and manufacturing can be performed stably. In addition, the 2 / 3 lap is performed by overlapping the variable thickness insulating tape 20 and / or the constant thickness insulating tape 3 by 2 / 3, so that the insulating coating 3 is ultimately three layers.

[0097] (Other configurations) An insulating sheath (not shown) made of extruded resin may be provided on the outermost circumference of the insulated electric wire 10 as necessary. This insulating sheath is provided on the outer circumference of the insulated electric wire 10 shown in FIG. 1, and the material is not particularly limited as long as it has insulating properties. As the constituent resin of the insulating sheath, various resins applied to resin extrusion can be used, for example, fluororesins such as PFA, ETFE, and FEP, vinyl chloride resins, polyolefin resins such as polyethylene, and polyester resins such as polyethylene terephthalate. The thickness of the insulating sheath can be within a range of, for example, about 0.05 to 1.0 mm. In addition, when the insulating coatings 2 and 3 are made to have different identifiability, it is preferable to use a non-colored transparent or translucent material for the extruded resin.

[0098] [coil] 13 is a development view of the configuration of a coil 40 according to the present invention. The coil 40 is obtained by winding the insulated electric wire 10 according to the present invention described above, and is characterized in that the insulating coating 3 of the insulated electric wire 10 is thick in a portion where the voltage is high and partial discharge is likely to occur, and the insulating coating 2 of the insulated electric wire 10 is thin in a portion where the voltage is not high and partial discharge is unlikely to occur.

[0099] In such a coil 40, the insulating coating 3 of the insulated electric wire is thick in the portion where partial discharge is likely to occur, so that it is possible to increase the partial discharge inception voltage, for example, at the jumper portion, and the insulating coating 2 of the insulated electric wire is thin in the portion where partial discharge is unlikely to occur, so that it is possible to increase the space factor without deteriorating it. Since these portions are provided repeatedly at arbitrary intervals, for example, when the coil is preferably applied as a coil for a three-phase induction motor, it is possible to use a thin insulating coating 2 at the slot conductor portion of the motor and a thick insulating coating 3 at the jumper portion where a high voltage is applied that connects the slot conductor portions of the motor.

[0100] 13 is a configuration development diagram of coil 40 when used for a three-phase induction motor. In the configuration development diagram, the coil is composed of circumferential conductor portions E1-E9, straight conductor portions PS1-PS10, front portions E1M-E9M, unformed step portions KA1-KA9, rear portions E1N-E9N, and bent ends SS1, SS2. In this case, the thin insulating coating 2 of insulated wire 10 is arranged on straight conductor portions PS1-PS10. On the other hand, the thick insulating coating 3 of insulated wire 10 is arranged on circumferential conductor portions E1-E9.

[0101] In this way, the insulated wire placed in the stator slot conductor section has a thin insulating coating 2 that can withstand the application of a phase voltage, thereby increasing the space factor of the coil winding. In addition, in the case of a three-phase induction motor, each phase voltage is applied to the stator slot conductor section, so the jumper section connecting the stator slot conductor sections approaches or comes into contact with the jumper sections of other phases, and the phase-to-phase voltage of the other phase, specifically the line voltage (√3 times the phase voltage), is applied to the jumper section. As a result, partial discharges are likely to occur at the jumper section, but by using a thick insulating coating 3 for the jumper section connecting the stator slot conductor section to which the line voltage is applied, the partial discharge inception voltage of the jumper section can be increased.

[0102] At this time, by configuring the thin insulating coating 2 of the insulated wire 10 and the thick insulating coating 3 of the insulated wire 10 to have different visibility to correspond to each arrangement, the insulating coatings 2, 3 can be clearly distinguished from each other, improving the ease of arrangement work.

[0103] [Manufacturing method of variable thickness insulating tape] The manufacturing method of variable thickness insulating tape 20 of the present invention is a manufacturing method of a tape in which thin portions 21 and thick portions 22 are repeatedly provided, and although the method is not particularly limited, examples of the method include the methods shown in Figures 14 to 16.

[0104] (a) The method shown in Figure 14 is a method in which a laminated base tape 24' is temporarily adhered onto a thin base material tape 23, and the laminated base tape 24' is then removed in a specified shape, and the remaining part of the laminated base tape 24' is used as the laminated tape 24 (thick part 22).

[0105] First, as shown in FIG. 14(A), a lamination base tape 24' of the same size is temporarily attached onto a thin base tape 23. The temporary attachment can be performed by various means, and is not particularly limited, but examples include a method of temporarily attaching them by bonding with an adhesive, and a method of temporarily attaching them by heat by lamination. The type and thickness of the adhesive are as described above. The adhesive may be provided on the base tape 23, may be provided on the lamination base tape 24', or may be provided on both tapes 23, 24. From the viewpoint of visibility, it is preferable to provide a colored adhesive on the lamination tape 24.

[0106] If the adhesive is tacky, it is temporarily bonded by applying pressure, but if the adhesive is thermally adhesive, it is temporarily bonded by applying pressure and heating. The adhesive may also be supplied by pouring it between the two tapes when they are bonded together. Lamination is performed by thermal lamination, and for example, temporary bonding can be achieved by applying pressure with a heated roll while applying heat.

[0107] After the temporary bonding, as shown in Figures 14(B) and (C), the laminating tape 24 is left and the rest is removed. The removal method involves inserting a blade from the laminating base tape 24' side to form a cut 53, and then peeling off and removing the outside of the portion surrounded by the cut 53. The length and shape of the portion to be removed can be determined by the size and shape of the cutting blade. By making successive cuts 53 with the cutting blade, the portion to be removed can be formed continuously.

[0108] When the thin base tape 23 and the laminated base tape 24' are temporarily bonded together, the base tape 23 and the laminated base tape 24' are preferably bonded together by temporary bonding as described above. This temporary bonding allows the thin base tape 23 and the laminated base tape 24' to be easily peeled off after being laminated together by adjusting the applied pressure and / or heating temperature. After the laminated tape 24 is produced by temporary bonding, the thin base tape 23 and the laminated tape 24 can be permanently bonded together by applying pressure and / or heating.

[0109] (A) The method shown in FIG. 15 is a method of laminating a laminating tape 24 that will become a thick portion 22 formed into a predetermined shape onto a thin base tape 23. First, as shown in FIG. 15(A), a base tape 23 is prepared. Next, as shown in FIG. 15(B), a plurality of laminating tapes 24 of a predetermined size are prepared, or a plurality of laminating tapes 24 are prepared by laminating them onto a process tape 51 with any light adhesive means. Note that the process tape 51 is shown with a dashed line, which means that the use of the process tape 51 is optional. Finally, as shown in FIG. 15(C), a plurality of laminating tapes 24 are directly laminated onto the base tape 23 at predetermined intervals with any adhesive means.

[0110] (c) The method shown in FIG. 16 is a method in which a slit laminating tape 24" which becomes the thick portion 22 slit to a specified width is laminated to a base tape 23 which becomes the thin portion and then cut, or a method in which cutting is performed simultaneously with the heat press for lamination. First, as shown in FIG. 16(A), a base tape 23 is prepared. Next, as shown in FIG. 16(B), a laminating tape 24" which is slit to a specified width is prepared, and with a specified length unrolled in the width direction of the base tape 23, the tape is laminated to a position matching the width of the base tape 23. Finally, as shown in FIG. 16(C), the slit laminating tape 24" is directly laminated onto the base tape 23 at a specified interval and then cut, or the tape is cut simultaneously with the heat press for lamination.

[0111] (E) The method shown in FIG. 17 is a method in which a laminated base tape 24' which will become the thick portion 22 is overlapped and laminated on a process tape 51, the laminated base tape 24' is removed in a specified shape to make the remaining portion of the laminated base tape 24' into the laminated tape 24 (thick portion 22), a thin base tape 23 is laminated on the laminated tape 24 which will become the thick portion 22, and finally the process tape 51 is removed.

[0112] In this method, first, as shown in FIG. 17(A), a process tape 51 is prepared, and a laminated base tape 24' is laminated thereon via an adhesive layer 52. The other side of the laminated base tape 24' is preferably provided with a colored adhesive layer 25 from the viewpoint of visibility. Therefore, the laminated base tape 24' is laminated to the process tape 51 in a manner that the adhesive layers 52, 25 are provided on both sides. The process tape 51 does not constitute the thickness-changing insulating tape 20 according to the present invention, and is only used in the manufacturing process, but may be provided as a protective release tape that is provided as it is and peeled off when used. The process tape 51 may be the same as the base tape 23, etc., or may be a resin tape other than the above. The thickness of the process tape 51 is not particularly limited as long as it does not interfere with the manufacturing process. As for the adhesive layers 52, 25, it is preferable that the adhesive layer 52 on the side of the process tape 51 that will eventually be peeled off has a weaker adhesive strength than the adhesive layer 25 on the side that will be laminated to the base tape 23. The type of adhesive is selected from this viewpoint.

[0113] Next, as shown in Figures 17(B) and (C), the laminated base tape 24' is removed in a predetermined shape after the temporary bonding in the same manner as in the temporary bonding method in Figure 14, and the remaining part of the laminated base tape 24' is made into the laminated tape 24 (thick part 22). As a means for this, as shown in Figure 17(B), a blade is inserted from the side of the laminated base tape 24' to form a cut 53, and as shown in Figure 17(C), the outside of the part surrounded by the cut 53 is peeled off and removed. The length and shape of the part to be removed can be determined by the size and shape of the cutting blade. By continuously inserting the cuts 53 with the cutting blade, the part to be removed can be formed continuously.

[0114] 17(D), the thin base tape 23 is laminated onto the laminating tape 24 that will become the thick portion 22. Since an adhesive layer 25 is provided on the laminating tape 24, the base tape 23 can be laminated from above and bonded by applying pressure and / or heat.

[0115] Finally, as shown in Fig. 17(E), the process tape 51 is removed. As described above, the process tape 51 may be provided as a protective release tape that is left as is and peeled off when used.

[0116] Each of the above manufacturing methods (A) to (D) may include a step of bonding a cover tape 27 via an adhesive layer 25a onto the bonding tape 24 that will become the thick portion 22. By doing so, as shown in Fig. 4(B) and Fig. 18, it is possible to obtain a so-called sandwich structure composed of the base tape 23, the bonding tape 24 bonded onto one main surface F1 of the base tape 23 via an adhesive layer 25, and the cover tape 27 that entirely covers the bonding tape 24 via the adhesive layer 25a.

[0117] As described above, the variable thickness insulating tape 20 according to the present invention can vary the tape thickness in a repeated manner, and is therefore suitable for use in components that require different properties at intervals. The variable thickness insulating tape 20 manufactured by the above methods (A) to (D) can be attached to components or members, and can increase the strength or insulation of the thick portion 22 compared to the thin portion 21, for example, and is expected to be used in a variety of applications. Moreover, this method has the advantage of not requiring many steps or complicated work. The manufactured tape can be distributed and sold as a wound tape roll. EXAMPLES

[0118] The present invention will be described in more detail with reference to examples. The present invention is not limited to the following examples, and those skilled in the art may make various changes, modifications and alterations within the scope of the present invention.

[0119] [Example 1] The insulated wire of Example 1 is the insulated wire 10A of the first embodiment shown in Fig. 5, which is an insulated wire 10A in which the variable thickness insulating tape 20 shown in Fig. 4(A) is wound around the outer periphery of a copper wire having a diameter of 1.0 mm. Here, the tape portion 22 of the insulated wire 10A is configured to be colored.

[0120] The variable thickness insulating tape 20 is formed by laminating tapes 24, each 25 μm thick and 65 mm long, at 40 mm intervals to a 12 μm thick base tape 23 via a 2 μm thick colored adhesive layer 25. An adhesive layer 26 is provided on the main surface F1 of the laminating tape surface side S1 of the variable thickness insulating tape 20. The variable thickness insulating tape 20 is wrapped around the conductor 1 in a half wrap (1 / 2 wrap) with the laminating tape surface side S1 facing the conductor 1.

[0121] In the obtained insulated wire 10A, the tape portion 21 which becomes the thin insulating coating 2 has a total average thickness including the adhesive layer 26 of 23 μm, and the colored tape portion 22 which becomes the thick insulating coating 3 has a total average thickness including the colored adhesive layer 25 and the adhesive layer 26 of 62 μm. In the obtained insulated wire 10A, the average diameter of the thick insulating coating portion is 1.12 mm, and the average diameter of the thin insulating coating portion is 1.05 mm. The thicknesses and average diameters are shown in Table 1. By winding the insulated wire 10A around the conductor 1 with the convex portion of the lamination tape surface side S1 facing inward, the surface of the insulated wire 10A becomes smooth, which is preferable when it is wound around a coil for use. In this case, since the difference in average diameter between the thick insulating coating 3 portion and the thin insulating coating 2 portion of the insulated wire 10A is 0.07 mm, it becomes difficult to visually distinguish between the insulating coatings 2, 3. However, by coloring the thick insulating coating 3 as in this embodiment, the visibility of the insulating coatings 2, 3 is made different, and therefore it becomes possible to easily distinguish between the thick insulating coating 3 portion and the thin insulating coating 2 portion.

[0122] [Example 2] The insulated wire of Example 2 is the insulated wire 10B of the second embodiment shown in Fig. 6, which is an insulated wire 10B in which the variable thickness insulating tape 20 and the constant thickness insulating tape 30 shown in Fig. 4(A) are wound around the outer periphery of a copper wire having a diameter of 1.0 mm. Here, the tape portion 22 of the insulated wire 10B is configured to be colored.

[0123] The variable thickness insulating tape 20 is formed by laminating a 25 μm thick, 65 mm long colored laminating tape 24 to a 12 μm thick base tape 23 at 40 mm intervals via a 2 μm thick colored adhesive layer 25. An adhesive layer 26 is provided on the main surface F2 of the flat side S2 of the base tape of the variable thickness insulating tape 20. The variable thickness insulating tape 20 is wrapped twice around the conductor 1 with a half wrap (1 / 2 wrap) with the laminating tape surface side S1 facing the conductor 1. The constant thickness insulating tape 30 is transparent and has a 2 μm thick adhesive layer on a 9 μm thick tape. The constant thickness insulating tape 30 is wrapped in the opposite direction to the variable thickness insulating tape 20 with a 1 / 3 wrap with the adhesive layer side on the inside.

[0124] In the obtained insulated wire 10B, the tape portion 21 which becomes the thin insulating coating 2 has a total average thickness of 40 μm including the adhesive layer 26, and the tape portion 22 which becomes the colored thick insulating coating 3 has a total average thickness of 78 μm including the colored adhesive layer. In the obtained insulated wire 10B, the average diameter of the thick insulating coating portion is 1.16 mm, and the average diameter of the thin insulating coating portion is 1.08 mm. The thickness and average diameter are shown in Table 1. At this time, the color of the colored tape portion 22 which becomes the thick insulating coating 3 can be identified through the transparent uniform thickness insulating tape 30. Since the visibility of the insulating coatings 2, 3 differs due to the coloring of the thick insulating coating 3, the thick insulating coating 3 portion and the thin insulating coating 2 portion can be easily identified.

[0125] [Example 3] The insulated wire of Example 3 is the insulated wire 10C of the third embodiment shown in Fig. 7, which is an insulated wire 10C in which the variable thickness insulating tape 20 shown in Fig. 4(A) is wound around the outer periphery of a copper wire having a diameter of 1.0 mm. Here, the tape portion 22 of the insulated wire 10C is configured to be colored.

[0126] The variable thickness insulating tape 20 is formed by laminating a 25 μm-thick, 65 mm-long colored laminating tape 24 to a 12 μm-thick base tape 23 at 40 mm intervals via a 2 μm-thick colored adhesive layer 25. The variable thickness insulating tape 20A that is wound first has an adhesive layer 26 on the flat side S2 of the base tape. The variable thickness insulating tape 20B that is wound on top of it has an adhesive layer 26 on the laminating tape surface side S1. The variable thickness insulating tape 20A is wound twice around the conductor 1 with a half wrap (1 / 2 wrap) with the base tape 23 side facing the conductor 1. The variable thickness insulating tape 20B that is wound on top of it in the opposite direction is wound around the conductor 1 with a 1 / 3 wrap in the opposite direction to the variable thickness insulating tape 20A with the laminating tape surface side S1 facing the conductor 1.

[0127] In the obtained insulated wire 10C, the tape portion 21 which becomes the thin insulating coating 2 has a total average thickness including the adhesive layer of 43 μm, and the colored tape portion 22 which becomes the thick insulating coating 3 has a total average thickness including the adhesive layer of 113 μm. In the obtained insulated wire 10C, the average diameter of the thick insulating coating portion is 1.23 mm, and the average diameter of the thin insulating coating portion is 1.09 mm. The thicknesses and average diameters are shown in Table 1. At this time, the thick insulating coating 3 portion can be identified because the tape portion 22 is colored, and the thick insulating coating 3 portion and the thin insulating coating 2 portion can be easily distinguished from each other.

[0128] [Example 4] The insulated wire 10D of Example 4 is the insulated wire 10D of the fourth embodiment shown in Fig. 8, and is an insulated wire 10D in which a variable thickness insulating tape 20 and a constant thickness insulating tape 30 are wound around the outer periphery of a copper wire having a diameter of 1.0 mm. Here, the tape portion 22 of the insulated wire 10D is configured to be colored.

[0129] The variable thickness insulating tape 20 is formed by laminating a 25 μm thick, 65 mm long, colored laminating tape 24 to a 12 μm thick base tape 23 at 40 mm intervals via a 2 μm thick colored adhesive layer 25. An adhesive layer 26 is provided on the flat side S2 of the base tape of the variable thickness insulating tape 20. The variable thickness insulating tape 20 is wound around the conductor 1 three times with 2 / 3 wrap, with the base tape 23 side facing the conductor 1. The constant thickness insulating tape 30 is formed by providing a 2 μm thick adhesive layer on a 9 μm thick tape. The constant thickness insulating tape 30 is wound in the opposite direction to the variable thickness insulating tape 20 with 1 / 3 wrap, with the adhesive layer side facing inward.

[0130] In the obtained insulated wire 10D, the tape portion 21 that becomes the thin insulating coating 2 has a total average thickness including the adhesive layer of 61 μm, and the colored tape portion 22 that becomes the thick insulating coating 3 has a total average thickness including the adhesive layer of 133 μm. In the obtained insulated wire 10D, the average diameter of the thick insulating coating portion is 1.27 mm, and the average diameter of the thin insulating coating portion is 1.12 mm. The thicknesses and average diameters are shown in Table 1. At this time, the colored tape portion 22 that becomes the thick insulating coating 3 can be identified through the transparent uniform-thickness insulating tape 30, and the thick insulating coating 3 portion and the thin insulating coating 2 portion can be easily identified.

[0131] [Example 5] The insulated wire of Example 5 is similar to the insulated wire 10C of the third embodiment shown in Fig. 7 as in Example 3, but the thickness-variable insulating tape 20 in Example 5 is thinner than that in Example 3. The average thickness and average diameter are shown in Table 1.

[0132] [Example 6] For the insulated wire of Example 6, the insulated wire 10A of the first embodiment shown in Fig. 5 was produced similarly to Example 1, and then an extruded resin layer made of ETFE resin was provided on the outer periphery of the insulated wire as an insulating outer sheath. The average thickness and average diameter are shown in Table 1.

[0133] [Example 7] The insulated wire of Example 7 is the insulated wire 10B of the second embodiment shown in Fig. 6 like Example 2, but the variable thickness insulating tape 20 used was a so-called sandwich-structure variable thickness insulating tape 20 shown in Fig. 4(B). Here, the tape portion 22 of the insulated wire 10B is configured to be colored.

[0134] The sandwich-structured variable thickness insulating tape 20 is composed of a 6 μm-thick base tape 23, a 25 μm-thick colored laminating tape 24 laminated onto the base tape 23 via a 2 μm-thick colored adhesive layer 25, and a 6 μm-thick cover tape 27 that covers the laminating tape 24 entirely via a 2 μm-thick adhesive layer 25a. The constant thickness insulating tape 30 is a transparent 9 μm-thick tape with a 2 μm-thick adhesive layer. The constant thickness insulating tape 30 is wound in the opposite direction to the variable thickness insulating tape 20, with the adhesive layer side facing inward, with 1 / 3 laps.

[0135] This insulated wire had a total average thickness of 43 μm in the thin parts and 81 μm in the thick parts. The thickness and average diameter are shown in Table 1. At this time, the color of the colored tape portion 22 that becomes the thick insulating coating 3 can be identified through the transparent uniform thickness insulating tape 30. This makes it easy to distinguish between the thick insulating coating 3 part and the thin insulating coating 2 part.

[0136] [Comparative Examples 1 and 2] Comparative Example 1 is an enameled wire with a baked-on varnish coating with an insulating coating thickness of 0.04 mm. Comparative Example 2 uses two of the same constant-thickness insulating tapes 30 as used in Example 2, each wrapped in 1 / 2 wrap in the opposite directions. The thickness and outer diameter are shown in Table 1.

[0137] [Measurement of partial discharge inception voltage] The partial discharge voltage was measured for the insulated wires of Examples 1 to 7 and Comparative Examples 1 and 2. The samples were in a two-ply twisted shape according to JIS C3216-5, and the partial discharge voltage was measured according to IEC60034-18 using XT-350PB39b manufactured by Adfox Co., Ltd. The results are shown in Table 1.

[0138] [Table 1]

[0139] [Evaluation Results] In the insulated wire of Example 1, the thin insulating coating portions were thinner than the coating of the insulated wires of Comparative Examples 1 and 2, and the thick insulating coating portions were about 1.5 times the coating of the insulated wires of Comparative Examples 1 and 2, and the partial discharge inception voltage was increased by 35% compared to Comparative Example 1. In the insulated wire of Example 2, the thin insulating coating portions were equivalent to the coating of the insulated wires of Comparative Examples 1 and 2, and the thick insulating coating portions were about twice the coating of the insulated wires of Comparative Examples 1 and 2, and the partial discharge inception voltage was increased by 53% compared to Comparative Example 1. In the insulated wire of Example 3, the thin insulating coating portions were approximately equivalent to the coating of the insulated wires of Comparative Examples 1 and 2, and the thick insulating coating portions were about 2.8 times the coating of the insulated wires of Comparative Examples 1 and 2, and the partial discharge inception voltage was increased by 87% compared to Comparative Example 1. In the insulated wire of Example 4, the thin insulating coating portion was about 1.5 times the coating of the insulated wire of Comparative Examples 1 and 2, and the thick insulating coating portion was about 3.3 times the coating of the insulated wire of Comparative Examples 1 and 2, and the partial discharge inception voltage was increased by 135% compared to Comparative Example 1. In the insulated wire of Example 5, the thin insulating coating portion was about 0.87 times the coating of the insulated wire of Comparative Examples 1 and 2, and the thick insulating coating portion was about 1.5 times the coating of the insulated wire of Comparative Examples 1 and 2, and the partial discharge inception voltage was increased by 35% compared to Comparative Example 1. In the insulated wire of Example 6, the thin insulating coating portion was about 1.8 times the coating of the insulated wire of Comparative Examples 1 and 2, and the thick insulating coating portion was about 2.5 times the coating of the insulated wire of Comparative Examples 1 and 2, and the partial discharge inception voltage was increased by 73% compared to Comparative Example 1. In the insulated wire of Example 7, the thin insulating coating was approximately equivalent to the coating of the insulated wires of Comparative Examples 1 and 2, and the thick insulating coating was approximately twice as thick as the coating of the insulated wires of Comparative Examples 1 and 2. The partial discharge inception voltage was increased by 54% compared to Comparative Example 1.

[0140] On the other hand, the coating thickness of the insulated wire of Comparative Example 2 is that of a typical tape-wrapped insulated wire, and is almost the same as that of the enameled wire with a baked varnish coating of about 0.04 mm, which is the insulated wire of Comparative Example 1. The partial discharge inception voltage of the insulated wire of Comparative Example 2 was increased by about 20% compared to that of the insulated wire of Comparative Example 1.

[0141] As described above, it is found that the partial discharge inception voltage of the thick insulating coating is improved in Examples 1 to 7 compared to Comparative Examples 1 and 2. By using this thick portion as, for example, a "bridge" that connects the stator slot conductor of a motor, the partial discharge inception voltage can be increased. In particular, in a coil using a thin wire with a conductor cross-sectional size of about 1.0 mmφ as in the examples, it is necessary to improve the adhesion of the insulating coating to the conductor and the positioning accuracy of the thick insulating coating so that it corresponds to the bridge of the coil. In such a case, since the insulated wire of the present invention has different thicknesses of the insulating coating repeatedly formed at predetermined intervals, the process of coil fabrication can be simplified. [Explanation of symbols]

[0142] 1 Conductor 2 Thin insulation 3. Thick insulation 3a Tapered section 3b Main body 10,10A~10D insulated wire 19 Boundary between thick and thin regions 20, 20A, 20B Thickness-variable insulating tape 21 Tape part (thin part) 22, 22a, 22b, 22c Tape section (thick part) 23 Base tape 24 Bonding Tape 24' Laminated Base Tape 24" Slit Laminating Tape 25 Adhesive layer 25a Adhesive layer 26 Adhesive layer 27 Cover Tape 30 Constant thickness insulating tape 31 Lap section 32 Non-wrapped section A Thick area B Thin area F1 One main surface of the base tape F2 The other main surface of the base tape S1 Surface side of adhesive tape S2 Flat side of base tape L1, L2, L3: Length of thick part in the longitudinal direction P1, P2, P3 Distance between thick parts θ1 Winding angle of the thickness-varying insulating tape relative to the longitudinal direction of the conductor θ2 Thickness change Angle of the boundary between the thick and thin areas with respect to the longitudinal direction of the insulating tape θ3 Angle between the boundary line of the thickness-varying insulating tape and the longitudinal direction of the conductor 40 Coil configuration E1~E9 Circumferential conductor section PS1~PS10 Straight conductor section E1M~E9M Front of the circular conductor KA1~KA9 Unformed step area E1N~E9N Circular conductor section rear SS1,SS2 bent ends 51 Process Tape 52 Adhesive layer (adhesive layer) 53 Cut

Claims

1. An insulated wire having a conductor and an insulating coating provided around the conductor, the insulated wire being composed of a thick insulating coating and a thin insulating coating, the thick insulating coating and the thin insulating coating being provided repeatedly at an arbitrary interval, and the thick insulating coating and the thin insulating coating being formed by wrapping a thickness-changing insulating tape having thick regions and thin regions at a predetermined interval around the conductor.

2. The insulated wire of claim 1 , wherein the thick insulating coating and the thin insulating coating are configured to have different visibility.

3. 3. The insulated electric wire as described in claim 1 or 2, wherein the thickness-changing insulating tape is composed of a base tape and a laminating tape laminated onto one of the main surfaces of the base tape, or is composed of a base tape, a laminating tape laminated onto one of the main surfaces of the base tape, and a cover tape further laminated onto the laminating tape in a manner covering the laminating tape.

4. The variable thickness insulating tape further has an adhesive layer formed on one main surface of the base tape and on the laminating tape, or on the other main surface of the base tape, 4. The insulated wire according to claim 3, wherein the thickness-changing insulating tape that is first wrapped around the outer circumference of the conductor is wrapped with the adhesive layer on the inside, i.e., the conductor side or the outside, and another thickness-changing insulating tape that is placed on top of it is wrapped with the adhesive layer on the inside and the laminating tape surface side on the inside.

5. 5. The insulated wire according to claim 1, wherein the variable thickness insulating tape is wound around the outer periphery of the conductor, and another variable thickness insulating tape or a constant thickness insulating tape is wound around the outer periphery of the variable thickness insulating tape, so that the thick insulating coating and the thin insulating coating are repeated.

6. 6. The insulated wire according to claim 5, wherein when another variable thickness insulating tape is wound on top of the variable thickness insulating tape, the thick region of the other variable thickness insulating tape is wound so as to overlap the already formed thick insulating coating.

7. 7. The insulated wire according to claim 4, wherein when the variable thickness insulating tape is wound and another variable thickness insulating tape or a constant thickness insulating tape is wound on top of the variable thickness insulating tape, the other variable thickness insulating tape and the constant thickness insulating tape are wound in different winding directions from the variable thickness insulating tape.

8. An insulated wire as described in any one of claims 1 to 7, further comprising an extruded resin layer as an insulating outer coating.

9. An insulated wire having a conductor and an insulating coating provided around the conductor, characterized in that the insulated wire is composed of a thick insulating coating and a thin insulating coating, the thick insulating coating and the thin insulating coating are repeatedly provided at any intervals, the thick insulating coating has tapered portions at both ends, and the tapered portions have a taper ratio of 0.5 / 1000 or more and 150 / 1000 or less.

10. 10. The insulated wire according to claim 9, wherein the thick insulating coating and the thin insulating coating are formed by wrapping a variable thickness insulating tape having thick and thin regions at predetermined intervals around the outer periphery of the conductor, and the variable thickness insulating tape has a boundary line between the thick and thin regions formed obliquely with respect to a longitudinal direction of the variable thickness insulating tape.

11. 11. The insulating coating of claim 10, wherein the insulating tape is wound in a direction such that θ1 is in the range of 10° to 60° and θ2 is in the range of 10° to 90°, where θ1 is the winding angle of the variable thickness insulating tape relative to the longitudinal direction of the conductor, θ2 is the angle of the boundary between the thick and thin regions relative to the longitudinal direction of the variable thickness insulating tape, and θ3 is the angle between the boundary of the variable thickness insulating tape and the longitudinal direction of the conductor.

12. The insulating coating according to claim 11, wherein θ3 is 0°.

13. The insulated wire according to any one of claims 9 to 12, further comprising an extruded resin layer as an insulating outer covering.

14. 14. A coil obtained by winding the insulated wire according to any one of claims 1 to 13, wherein the insulated wire is composed of a portion provided with a thick insulating coating and a portion provided with a thin insulating coating, and the thick insulating coating and the thin insulating coating are provided repeatedly at any interval.

15. A variable thickness insulating tape that functions as an insulating coating and is wound around the outer circumference of a conductor constituting an insulated electric wire to form a thick insulating coating and a thin insulating coating, A variable thickness insulating tape comprising an insulating material and having alternating thin and thick portions.

16. 16. The variable thickness insulating tape of claim 15, wherein the thickness of the thicker portion is between 1.5 and 8 times the thickness of the thinner portion.

17. 17. The variable thickness insulating tape of claim 15 or 16, wherein the thickened portion is colored.

18. A thickness varying insulating tape according to any one of claims 15 to 17, wherein the thin portion is composed of a base tape, and the thick portion is composed of the base tape and a bonding tape bonded onto one main surface of the base tape.

19. A thickness varying insulating tape as described in any one of claims 15 to 17, wherein the thin portion is constituted by an overlapping base tape and a cover tape, and the thick portion is constituted by a laminated tape sandwiched between the base tape and the cover tape and laminated onto one main surface of the base tape.

20. 20. The variable thickness insulating tape of claim 18 or 19, wherein the laminating tape is colored.

21. The variable thickness insulating tape according to any one of claims 18 to 20, wherein the base tape and the laminating tape are made of insulating materials having the same level of heat resistance.

22. 22. The variable thickness insulating tape according to claim 15, wherein a boundary line between the thick portion and the thin portion is formed obliquely with respect to a longitudinal direction of the variable thickness insulating tape.

23. The variable thickness insulating tape according to any one of claims 15 to 22, which functions as an insulating coating provided on the outer periphery of a conductor constituting an insulated electric wire.

24. The manufacturing method of a variable thickness insulating tape is made of an insulator and has repeated thin and thick sections, and is characterized by being any one of (a) to (d) below. (A) A method in which a laminated base tape that will become the thick portion is temporarily adhered to a base tape that will become the thin portion, and the laminated base tape is removed in a predetermined shape, so that the remaining part of the laminated base tape becomes the thick portion; (a) a method of laminating a lamination tape formed into a predetermined shape to become the thick portion to a base tape to become the thin portion; (c) A method in which a bonding tape that becomes the thick portion, which has been slit to a predetermined width, is bonded to a base tape that becomes the thin portion and then cut, or a method in which the bonding tape and base tape are heat-pressed and cut at the same time; (E) A method in which a laminated base tape that will become the thick portion is temporarily adhered onto a process tape, the laminated base tape is removed in a predetermined shape to make the remaining portion of the laminated base tape into the thick portion, a base tape that will become the thin portion is laminated onto a second tape that will become the thick portion, and finally the process tape is removed.

25. 25. The method of claim 24, further comprising laminating a cover tape onto the laminating tape.

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