Patent Application
20230099218
The present invention relates to an insulated wire in which a thickness of an insulating coating can be changed as desired to increase a partial discharge (corona discharge) starting voltage, a coil that uses the insulated wire, a variable-thickness insulating tape used in manufacture of the insulated wire, and a manufacturing method of the same.
Insulated wires are used in various products. In a case in which an insulated wire is used as a winding for a coil or the like of a rotating electrical device such as a motor, the insulated wire is used with high voltage applied. At this time, a severe partial discharge (corona discharge) may occur on an insulation-coated surface. Such partial discharge is a phenomenon caused by accelerated deterioration of the insulating coating due to local temperature rise and generation of ozone and ions. The occurrence of partial discharge creates the problem of shortening the life of the device in which the component is used.
In recent years, with increasing demand for compact and high-power motors, coils that can increase the applied voltage are in need. However, when the applied voltage is increased, the voltage applied to the coil increases and partial discharge is more likely to occur. In response to such problems, it is desirable to increase the voltage at which partial discharge occurs (referred to as partial discharge starting voltage), and thus, to increase the partial discharge starting voltage, various measures have been taken, such as thickening the insulating coating of an enameled wire, thickening the insulating coating by resin extrusion, and lowering the dielectric constant of the insulating coating by foaming. However, each of these methods result in a decrease in coil winding occupancy and a decrease in film strength, and are thus limited in causing an increase in partial discharge starting voltage.
Partial discharge tends to occur when high voltage is applied to a “crossing part” connecting a stator slot conductor part of the motor (slot conductor part refers to a mode in which wires are arranged in a slot). To solve such problems, Patent Documents 1 and 2, for example, describe the suppression of partial discharge and the like by changing a thickness and a material of the insulating material in the slot conductor part and the crossing part of the insulated wire.
Specifically, Patent Document 1 describes a method of winding and thus forming the conductor in a coil shape, subsequently forming an insulating layer in each portion that becomes the slot conductor part and the crossing part, and changing a thickness of each insulating layer. Further, Patent Document 2 describes a method of making a relative dielectric constant of a portion serving as the crossing part in a length direction of the insulated wire lower than a relative dielectric constant of the portion serving as the slot conductor part by adjusting a total volume of bubbles in the resin forming the insulating layer, and the like.
Patent Document 1: Japanese Laid-Open Patent Application Publication No. 2008-236924
Patent Document 2: Japanese Laid-Open Patent Application Publication No. 2015-138678
Nevertheless, to manufacture an insulated wire including an insulating layer that can exhibit insulation performance such as required at the time of coil design, the method of manufacturing the insulated wire such as mentioned above requires significant man-hours and complex processes. Further, it is difficult to manufacture, by enamel baking means or by resin extrusion, an insulated wire including an insulating coating of varying thickness so that insulation performance can be exhibited as required at the time of coil design.
The present invention has been made to solve the above-described problems, and an object thereof is to provide an insulated wire that can be manufactured without significant man-hours or complex processes, increase a partial discharge starting voltage, prevent deterioration of an insulator, and not cause worsening of an occupancy ratio, a coil that uses the insulated wire, a variable-thickness insulating tape used in manufacture of the insulated wire, and a manufacturing method of the same.
(1) An insulated wire according to the present invention is an insulated wire comprising a conductor, and an insulating coating provided on an outer periphery of the conductor, and is constituted by a thick insulating coating and a thin insulating coating, and the thick insulating coating and the thin insulating coating are repeatedly provided at desired intervals.
According to this invention, the thick insulating coating and the thin insulating coating are repeatedly provided at desired intervals, and thus, for example, the insulating coating can be thickened in an area where partial discharge readily occurs and in an area where high withstand voltage is required. As a result, for example, it is possible to increase the partial discharge starting voltage at a crossing part, or increase the withstand voltage in an area where high withstand voltage is required. Further, for example, the insulating coating can be thinned in a slot conductor part and in an area where the withstand voltage does not need to be so high, making it possible to improve and not worsen the occupancy ratio. These areas are repeatedly provided at desired intervals, and thus, for example, in a case in which the coil is preferably applied as a coil for a three-phase induction motor, the thin insulating coating can be set in the slot conductor part of the motor, and the thick insulating coating can be set in an area where high voltage of the crossing part connecting the slot conductor part of the motor is applied.
In the insulated wire according to the present invention, the thick insulating coating and the thin insulating coating are formed by an insulating tape including a thick region and a thin region at predetermined intervals (hereinafter referred to as “variable-thickness insulating tape”) being wound on the outer periphery of the conductor. According to this invention, the above-described variable-thickness insulating tape is wound on the outer periphery of the conductor, thereby making it possible to create an insulated wire in which a thick insulating coating and a thin insulating coating are repeatedly provided at desired intervals.
In the insulated wire according to the present invention, the thick insulating coating and the thin insulating coating are configured to have different visibilities. According to this invention, by making the visibilities different depending on the thickness of the insulating coating, it is possible to distinguish the thick insulating coating from the thin insulating coating. This makes it possible for a worker, a discrimination sensor, or the like to discriminate between the thin insulating coating and the thick insulating coating during coil fabrication, and thus make the coil manufacturing process easier.
In the insulated wire according to the present invention, the variable-thickness insulating tape is constituted by a base material tape and a bonding tape bonded onto one main surface of the base material tape, or is constituted by a base material tape, a bonding tape bonded onto one main surface of the base material tape, and a cover tape further bonded onto the bonding tape so as to cover the bonding tape. According to this invention, the variable-thickness insulating tape can have a simple structure constituted by the base material tape and the bonding tape, or a so-called sandwich structure constituted by the base material tape, the bonding tape, and the cover tape.
In the insulated wire according to the present invention, the variable-thickness insulating tape further includes an adhesive layer formed on the one main surface of the base material tape and on the bonding tape or on the other main surface of the base material tape. The variable-thickness insulating tape initially wound on the outer periphery of the conductor is wound with the adhesive layer being on the conductor side serving as an inside or on an outside, and another variable-thickness insulating tape further provided thereon is wound with the bonding tape surface side being on the inside and the adhesive layer being on the inside. According to this invention, the other main surface on the flat surface side of the base material tape can be firmly adhered to the conductor. It should be noted that, in the case of further winding in layers, another variable-thickness insulating tape further provided on the variable-thickness insulating tape is wound with the bonding tape surface side being on the inside and the adhesive layer also being on the inside, thereby making it possible to make an appearance of the insulating coating uniform and smooth. This has the effect of preventing the insulated wire from snagging on a jig used during processing, such as in a case of manufacturing a coil with an insulated wire, thereby making it possible to suppress the occurrence of scratches during processing. Further, easy peeling of the insulating coating can be realized by winding the variable-thickness insulating tape initially wound on the outer periphery of the conductor with the adhesive layer being on the outside.
In the insulated wire according to the present invention, the variable-thickness insulating tape is wound on the outer periphery of the conductor, another variable-thickness insulating tape or a constant-thickness insulating tape is further wound on an outer periphery of the variable-thickness insulating tape, and the thick insulating coating and the thin insulating coating are repeated. According to this invention, it is possible to obtain an insulated wire in which a plurality of the variable-thickness insulating tapes are wound to further thicken the thick insulating coating and increase the withstand voltage, or an insulated wire in which the constant-thickness insulating tape is further wound to thicken the thin insulating coating and adjust the occupancy ratio.
In the insulated wire according to the present invention, in a case in which the variable-thickness insulating tape is wound and then another variable-thickness insulating tape is further wound thereon, the other variable-thickness insulating tape is wound in a layer so that a thick region thereof overlaps the thick insulating coating already formed. According to this invention, the other variable-thickness insulating tape is wound in a layer so that the thick region thereof overlaps the thick insulating coating already formed, thereby making it possible to further thicken the thick insulating coating.
In the insulated wire according to the present invention, in a case in which the variable-thickness insulating tape is wound and then another variable-thickness insulating tape or a constant-thickness insulating tape is further wound in a layer thereon, the other variable-thickness insulating tape or the constant-thickness insulating tape is wound in a layer in a winding direction different from that of the variable-thickness insulating tape. According to this invention, in a case in which a plurality of insulating tapes are wound in layers, these insulating tapes are wound in layers in different winding directions, thereby making it possible to make the insulating coating thickness uniform and the surface smooth. This has the effect of preventing the insulated wire from snagging on a jig used during processing, such as in a case of manufacturing a coil with an insulated wire, thereby making it possible to suppress the occurrence of scratches during processing.
In the insulated wire according to the present invention, the thick insulating coating has a tapered part at both end parts thereof. According to this invention, the tapered part of the thick insulating coating can smoothly change the thick insulating coating to the thin insulating coating, resulting in the effect of preventing the insulated wire from snagging on a jig used during processing, such as in a case of manufacturing a coil with an insulated wire, thereby making it possible to suppress the occurrence of scratches during processing.
In the insulated wire according to the present invention, preferably the tapered part has a taper ratio from 0.5/1000 to 150/1000. By keeping the taper ratio within this range, it is possible to obtain an appropriate insulation thickness and exhibit favorable insulation characteristics.
In this case, the thick insulating coating and the thin insulating coating are formed by the variable-thickness insulating tape, including the thick region and the thin region at a predetermined interval, being wound on the outer periphery of the conductor, and the variable-thickness insulating tape has a boundary line between the thick region and the thin region obliquely formed with respect to a longitudinal direction of the variable-thickness insulating tape. According to this invention, it is possible to reduce abrupt changes in an outer diameter of the insulated wire around which the boundary line portion of the variable-thickness insulating tape is wound. As a result, the amount of change in the outer diameter is reduced, thereby making it possible to smoothen the surface. This has the effect of preventing the insulated wire from snagging on a jig used during processing, such as in a case of manufacturing a coil with an insulated wire, thereby making it possible to suppress the occurrence of scratches during processing.
In the insulated wire according to the present invention, given θ1 as a winding angle of the variable-thickness insulating tape with respect to a longitudinal direction of the conductor, θ2 as an angle of the boundary line between the thick region and the thin region with respect to the longitudinal direction of the variable-thickness insulating tape, and θ3 as an angle between the boundary line of the variable-thickness insulating tape and the longitudinal direction of the conductor, the θ1 is within a range from 10° to 60°, the θ2 is within a range from 10° to 90°, and the variable-thickness insulating tape is wound in a direction in which the θ2 is greater than the θ3. In particular, preferably the θ3 is 0°.
In the insulated wire according to the present invention, an extruded resin layer is further provided as an insulating outer coating.
(2) A coil according to the present invention is a coil obtained by winding the insulated wire according to the above-described present invention. The insulated wire includes a portion provided with the thick insulating coating, and a portion provided with the thin insulating coating. The thick insulating coating and the thin insulating coating are repeatedly provided at desired intervals.
According to this invention, a coil is obtained by winding the insulated wire repeatedly provided with the thick insulating coating and the thin insulating coating at desired intervals, thereby making it possible to use an insulated wire in which the insulating coating is thickened in an area where partial discharge readily occurs and in an area where high withstand voltage is required, for example. As a result, for example, it is possible to obtain a coil that increases the partial discharge starting voltage at a crossing part, or increases the withstand voltage in an area where high withstand voltage is required. Further, for example, it is possible to use the insulated wire obtained by thinning the insulating coating in a slot conductor part and in an area where the withstand voltage does not need to be so high, for example, and thus improve without worsen the occupancy ratio.
In this coil, preferably the insulating coating of the insulated wire in an area where voltage increases and partial discharge readily occurs is a thick insulating coating, and the insulating coating of the insulated wire in an area where voltage does not increase and partial discharge does not readily occur is a thin insulating coating. According to this invention, the insulating coating of the insulated wire in an area where partial discharge readily occurs is thick, thereby making it possible to, for example, increase the partial discharge starting voltage at the crossing part, and the insulating coating in an area where partial discharge does not readily occur is thin, thereby making it possible to improve without worsen the occupancy ratio. These areas are repeatedly provided at desired intervals, and thus, for example, in a case in which the coil is preferably applied as a coil for a three-phase induction motor, the thin insulating coating can be set in the slot conductor part of the motor, and the thick insulating coating can be set in an area where high voltage of the crossing part connecting the slot conductor part of the motor is applied.
(3) A variable-thickness insulating tape according to the present invention comprises an insulator, and a thin portion and a thick portion are repeated. According to this invention, by winding such a variable-thickness insulating tape on the outer periphery of the conductor, it is possible to form an insulating coating composed of a thick portion and a thin portion on the outer periphery of the conductor.
In the variable-thickness insulating tape according to the present invention, a thickness of the thick portion is 1.5 times to 8 times a thickness of the thin portion. According to this invention, the thickness of the thick portion of the variable-thickness insulating tape is within the above-described range, thereby making it possible to obtain an insulating coating that has high work efficiency when the variable-thickness insulating tape is wound on the outer periphery of the conductor, and has a sufficient difference in thickness.
In the variable-thickness insulating tape according to the present invention, the thick portion is colored. According to this invention, the thick portion can be easily recognized during tasks such as wrapping the variable-thickness insulating tape. Further, when the variable-thickness insulating tape is wound on the outer periphery of the conductor, the thick portion of the insulating coating formed on the outer periphery of the conductor may be a colored portion.
In the variable-thickness insulating tape according to the present invention, the thin portion is constituted by a base material tape, and the thick portion is constituted by the base material tape and a bonding tape bonded onto one main surface of the base material tape. According to this invention, it is possible to adopt a simple structure that does not require complex processes.
In the variable-thickness insulating tape according to the present invention, the thin portion is configured by layering a base material tape and a cover tape, and the thick portion is constituted by a bonding tape interposed between the base material tape and the cover tape and bonded onto one main surface of the base material tape. According to this invention, it is possible to adopt a simple structure that does not require complex processes and, furthermore, with use of the cover tape, improve a wrappability when winding on the outer periphery of the conductor.
In the variable-thickness insulating tape according to the present invention, the bonding tape is colored. According to this invention, it is possible to color the thick portion of the variable-thickness insulating tape with a simple structure that does not require complex processes.
In the variable-thickness insulating tape according to the present invention, the base material tape and the bonding tape are constituted by insulating materials having heat-resistant temperatures of the same level. According to this invention, it is possible to make the heat-resistant temperature of the variable-thickness insulating tape uniform, which is preferable in terms of heat resistance of an entire wire in a case of use as the insulating coating of an insulated wire.
In the variable-thickness insulating tape according to the present invention, a boundary line between the thick portion and the thin portion is obliquely formed with respect to a longitudinal direction of the variable-thickness insulating tape. According to this invention, when the variable-thickness insulating tape is wrapped around a conductor, it is possible to reduce the abrupt change in the outer diameter of the insulated wire in which a boundary portion in which the thickness of the variable-thickness insulating tape changes is wound. As a result, the amount of change in the outer diameter is reduced, thereby making it possible to smoothen the surface.
The variable-thickness insulating tape according to the present invention functions as an insulating coating provided on an outer periphery of a conductor constituting an insulated wire.
(4) A method of manufacturing a variable-thickness insulating tape according to the present invention is a method of manufacturing a variable-thickness insulating tape including an insulator and a thin portion and a thick portion repeatedly provided thereto, and is any one of the following (a) to (d): (a) a method of temporarily adhering a bonding base tape serving as the thick portion on a base material tape serving as the thin portion, removing the bonding base tape in a predetermined shape, and then using a remaining portion of the bonding base tape as the thick portion; (b) a method of bonding a bonding tape serving as the thick portion formed into a predetermined shape to a base material tape serving as the thin portion; (c) a method of bonding the bonding tape serving as the thick portion slit to a predetermined width to a base material tape serving as the thin portion and cutting the bonding tape thus bonded, or simultaneously cutting the bonding tape with a heating press that performs bonding; and (d) a method of temporarily adhering a bonding base tape serving as the thick portion on a process tape, removing the bonding base tape in a predetermined shape, using a remaining portion of the bonding base tape as the thick portion, bonding a base material tape serving as the thin portion onto the second tape serving as the thick portion, and lastly removing the process tape.
According to this invention, it is possible to manufacture a variable-thickness insulating tape including a base material tape composed of a thin portion and a bonding tape composed of a thick portion bonded on one main surface of the base material tape via an adhesive layer.
The method of manufacturing a variable-thickness insulating tape according to the present invention further comprises a process of bonding a cover tape onto the bonding tape. According to this invention, it is possible to adopt a sandwich structure including a cover tape that covers the bonding tape in its entirety via an adhesive layer on the bonding tape.
According to the present invention, it is possible to provide an insulated wire that can increase a partial discharge starting voltage, prevent deterioration of an insulator, and not cause worsening of an occupancy ratio, and a coil for a motor fabricated with the insulated wire. Further, according to the present invention, it is possible to provide a variable-thickness insulating tape used in the fabrication of an insulated wire constituted by a thick insulating coating and a thin insulating coating, and a manufacturing method of the same.
An insulated wire, a coil, a variable-thickness insulating tape, and a manufacturing method thereof according to the present invention will now be described with reference to the drawings. It should be noted that the present invention can be modified in various ways as long as the technical features set forth herein are present, and is not limited to forms of the descriptions and drawings below.
An insulated wire 10 according to the present invention, as illustrated in
In the insulated wire 10 according to the present invention, the insulating coating 3 of the insulated wire in an area where partial discharge readily occurs is thick, thereby making it possible to, for example, increase the partial discharge starting voltage at a crossing part, and the insulating coating 2 of the insulated wire in an area where partial discharge does not readily occur is thin, thereby making it possible to improve without worsen an occupancy ratio. These areas are repeatedly provided at desired intervals, and thus, for example, in a case in which the coil is preferably applied as the coil 40 for a three-phase induction motor, the thin insulating coating 2 can be set in a slot conductor part of the motor, and the thick insulating coating 3 can be set in an area where high voltage of the crossing part connecting the slot conductor part of the motor is applied. As a result, it is possible to provide an insulated wire that can increase a partial discharge starting voltage, prevent deterioration of an insulator, and not cause worsening of an occupancy ratio, and a coil for a motor fabricated with the insulated wire.
In the following, each component will be described.
The conductor 1 is not particularly limited as long as applied as a center conductor of the insulated wire 10, especially for a coil, and may be any type of conductor, regardless of material and twist configuration. For example, the conductor 1 may be constituted by a single strand extending in a longitudinal direction, may be constituted by several strands twisted together, or may be configured as a litz wire. The type of strand is not particularly limited as long as a good conductive metal, but preferable examples include a metal conductor having favorable conductivity, such as copper wire, copper alloy wire, aluminum wire, aluminum alloy wire, copper-aluminum composite wire, or any of these wires with a plating layer on a surface thereof. Copper wire and copper alloy wire are particularly preferred from the standpoint of coil use. As the plating layer, a solder plating layer, a tin plating layer, a gold plating layer, a silver plating layer, a nickel plating layer, or the like is preferred. Furthermore, a “conductor” or a “strand” covered with an enamel layer or the like for insulation, oxidation prevention, or the like are also included as a conductor and a strand in the present invention. A cross-sectional shape of the strand is also not particularly limited and, in the wire material thereof, may be a circular or substantially circular shape or may be a rectangular shape.
A cross-sectional shape of the conductor 1 is also not particularly limited, and may be a circular shape (including elliptical shape) or may be a rectangular shape or the like. A cross-sectional size of the conductor 1 is desirably as large as possible so that an electric resistance (alternating-current resistance, conductor resistance) is reduced to such an extent that the conductor 1 can be preferably used for coils, and examples thereof include an outer diameter of a circular strand of about 0.05 to 4 mm. Further, in the case of a rectangular strand, examples include a short side of about 0.3 to 5 mm and a long side of about 0.5 to 10 mm. A cross-sectional size of these conductors 1 is selected as appropriate depending on the application in which the coil is used, but the smaller this cross-sectional size, the higher the adhesion and the positioning accuracy required in the insulating coatings 2, 3 described below.
The insulating coatings 2, 3, as illustrated in
Materials of the insulating coatings 2, 3 are not particularly limited, and, for example, materials used in insulating tapes, such as polyethylene resin, polyester resin (polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and the like), polyimide resin, polyamide resin, polyamide-imide resin, polystyrene resin, polyphenylene sulfide resin, and polyether ether ketone (PEEK) can be preferably applied. Further, materials having conductivity such as aluminum foil, copper foil, or metal foil obtained by plating these with tin, nickel, gold, or other plating may be used. Furthermore, the material may be, among these resin materials as well, a fluorine-based resin with a low dielectric constant, such as perfluoroalkoxy alkane (PFA), ethylene tetrafluoro ethylene (ETFE), or fluorinated ethylene propylene (FEP) used as a dielectric material, or may be polyphenylene ether resin, polyolefin resin such as polypropylene, polyester resin, polyacrylic resin, or the like.
The thin insulating coating 2 preferably has a thickness within a range from 2 to 500 μm, and the thick insulating coating 3 preferably has a thickness thicker than that of the thin insulating coating 2 and within a range from 4 to 1000 μm. The respective thicknesses are set in correspondence with the characteristics of the coil in which the insulated wire 10 is to be used. Desirably, the thin insulating coating 2 has at least a thickness that satisfies the required withstand voltage, and normally preferably has a thickness of 2 μm or greater. On the other hand, desirably, the thick insulating coating 3 has at least a thickness that satisfies a withstand voltage to a level capable of increasing the required partial discharge starting voltage, and normally preferably has a thickness of 4 μm or greater. It should be noted that the thickness of the thick insulating coating 3 is 1.5 times to 8 times, preferably from 2 times to 7 times, the thickness of the thin insulating coating 2.
The insulating coatings 2, 3 preferably have visibilities different from each other. Specifically, the visibilities can be made different by changing a color, a pattern, an unevenness, or the like of each of the insulating coatings 2, 3. By making the insulating coatings 2, 3 have different visibilities from each other, it is possible to distinguish the thick insulating coating 3 from the thin insulating coating 2. This makes it possible for a worker, a discrimination sensor, or the like to discriminate between the thin insulating coating 2 and the thick insulating coating 3 during coil fabrication, and thus make the coil manufacturing process easier. It should be noted 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 preferred in terms of easiness of the manufacturing process in a case of using a variable-thickness insulating tape 20 described below.
Between the thin insulating coating 2 and a main body part 3b of the thick insulating coating 3 is a tapered part 3a, as illustrated in
It should be noted that the form illustrated in
The tapered part 3a has a taper ratio (“difference in taper diameter/length of tapered portion in axial direction”) preferably within a range from 0.5/1000 to 150/1000. In a case in which the taper ratio is less than 0.5/1000, the length of the tapered part 3a in the axial direction may be too long, making it difficult to obtain an appropriate insulation thickness. Further, in a case in which the taper ratio is greater 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 in insulation characteristics. The taper ratio is more preferably 1.0/1000 to 100/1000.
As illustrated in
The lengths of the thick portions 22 in the longitudinal direction and/or the intervals between the thick portions 22, as illustrated in
Such a variable-thickness insulating tape 20 is wound on the outer periphery of the conductor 1 illustrated in
As for thickness, a thickness of the tape part 22 serving as the thick region A is preferably 1.5 times to 8 times a thickness of the tape part 21 serving as the thin region B. In a case in which the thickness of the tape part 22 is less than 1.5 times the thickness of the tape part 21, the thickness of the thick insulating coating 3 formed by the tape part 22 being wound on the outer periphery of the conductor 1 may not be thick enough to the thin insulating coating 2 formed by the tape part 21 being wound on the outer periphery of the conductor 1. Further, in a case in which the thickness of the tape part 22 exceeds 8 times the thickness of the tape part 21, the variable-thickness insulating tape 20 is likely to fold or wrinkle when the tape part 22 is wound on the outer periphery of the conductor 1, resulting in an uneven appearance when fully wound. It should be noted that the thickness of the tape part 22 serving as the thick region A is preferably 2 times to 7 times the thickness of the tape part 21 serving as the thin region B.
A distance between the tape part 21 serving as the thin region B and the tape part 22 serving as the thick region A is, in a case in which a coil is fabricated with the insulated wire 10 obtained by winding the variable-thickness insulating tape 20 on the outer periphery of the conductor 1, designed in accordance with the degree of interval required between the thin insulating coating 2 and the thick insulating coating 3. This distance is designed taking into consideration a width, a winding pitch, a wrap, and the like of the variable-thickness insulating tape 20, and examples include, as illustrated in
As illustrated in
The base material tape 23 constitutes the tape part 21 serving as the thin region B, and the base material tape 23 and the bonding tape 24 constitute the tape part 22 serving as the thick region A. The variable-thickness insulating tape 20 is wound on the outer periphery of the conductor 1, thereby forming the insulating coating 2 in which a portion wound by the tape part 21 is thin, and forming the insulating coating 3 in which a portion wound by the tape part 22 is thick. The adhesive layer is not provided on the other main surface F2 of the base material tape 23.
On the other hand, an adhesive layer 26 is provided on the bonding tape 24. Further, the adhesive layer 26 is also provided on the one main surface F1 of the base material tape 23, which is the bonding tape surface side of the tape part 21 to which the bonding tape 24 is not bonded. The adhesive layer 26 is provided on the one main surface F1 of the base material tape 23, which is the bonding tape surface side of the tape part 21, and on the bonding tape 24, and thus this variable-thickness insulating tape 20 is wound on the outer periphery of the conductor 1 with the adhesive layer 26 side on the conductor side (inside).
It should be noted that, although not illustrated, the variable-thickness insulating tape may have a form in which the adhesive layer 26 is provided on the other main surface F2, which is a flat surface side of the base material tape 23, and not provided on the bonding tape 24 on a surface side S1 of the bonding tape. In this case, the variable-thickness insulating tape is wound around the conductor with a flat surface side S2 of the base material tape 23, that is, the other main surface F2 of the base material tape 23, being on the conductor side.
As illustrated in
The base material tape 23 and the cover tape 27 constitute the tape part 21 serving as the thin region B, and the base material tape 23, the bonding tape 24, and the cover tape 27 constitute the tape part 22 serving as the thick region A. The adhesive layer 26 is provided on the other main surface F2 of the base material tape 23 on the flat surface side S2. On the other hand, the adhesive layer is not provided on the cover tape 27. The adhesive layer 26 is provided on the other main surface F2 of the base material tape 23 on the flat surface side S2, and thus this variable-thickness insulating tape 20 is wound on the outer periphery of the conductor 1 with the adhesive layer 26 side on the conductor side (inside). It should be noted that, although not illustrated, the variable-thickness insulating tape may have a form in which the adhesive layer 26 is provided on the cover tape 27 and not provided on the flat surface side S2 of the base material tape 23, that is, the other main surface F2 of the base material tape 23. In this case, the variable-thickness insulating tape is wound around the conductor with the surface side S1 of the bonding tape being on the conductor side.
As illustrated in such
Further, the variable-thickness insulating tape 20 can be wound with the adhesive layer 26 being on an outside opposite to the conductor side. In this case, the tape is not firmly adhered to the conductor 1, making it easier to peel the insulating coatings 2, 3 of the variable-thickness insulating tape 20 during end part processing.
Materials of the base material tape 23 and the bonding tape 24 are preferably insulating materials having heat-resistant temperatures of the same level. With the heat-resistant temperatures of the base material tape 23 and the bonding tape 24 being the same level, heat resistances of the insulating coatings 2, 3 are also the same. In this way, the heat-resistant temperature of the variable-thickness insulating tape 20 is made uniform, and thus the heat-resistant temperatures of the insulating coatings 2, 3 are the same or substantially the same, which is preferable in terms of the heat resistance of the entire insulated wire. It should be noted that the heat-resistant temperatures being the same level refers to “Appended Table 11: Upper limits of operating temperatures of insulators used in electrical appliances and materials” stipulated in the Electrical Appliances and Material Safety Act specified by the Ministry of Economy, Trade, and Industry in Japan being the same.
Preferable examples of the adhesive layers 25, 26 include layers composed of thermoplastic resins such as acrylic, polyester, urethane, polyimide, polyvinyl chloride (PVC), or ethylene-vinyl acetate (EVA), or thermosetting resins such as an epoxy or bismaleimide. The thicknesses of the adhesive layers 25, 26 are, for example, desirably within a range from 0.2 μm to 50 μm, and preferably within a range from 0.5 μm to 40 μm, in particular.
The adhesive layers 25, 26 are adhesive layers that can be obtained by applying an adhesive coating obtained by dissolving these resins in an organic solvent to a predetermined thickness (2 μm, for example) by using a coating device for gravure printing or the like, for example. It should be noted that such an adhesive layer may be provided not only (as the adhesive layer 25) between the base material tape 23 and the bonding tape 24, but also (as the adhesive layer 25a) between the base material tape 23 and the cover tape 27 or as the adhesive layer 26 on one surface side (S1 or S2) of the variable-thickness insulating tape 20.
Thicknesses of the thin insulating coating 2 and the thick insulating coating 3 are designed as desired, depending on a degree of overlap (wrap) of the tape part 21 and the tape part 22 wound on the outer periphery of the conductor 1, the thickness of the tape further wound on outsides of the tape part 21 and the tape part 22, and the like. For example, in a case in which the tape part 21 is wound by ½ wrap, the tape part 21 has a two-layered structure as illustrated in
The tape part 22 is also wound on the outer periphery of the conductor 1, and thus the thickness of tape part 22 is the sum of the thickness of the base material tape 23, the thickness of the bonding tape 24, and the thickness of the adhesive layer 25 provided therebetween, and is designed in correspondence with the degree of overlap of tape part 22. For example, in a case in which the tape part 22 is wound by ½ wrap, the tape part 22 has a two-layered structure as illustrated in
It should be noted that, in a case in which the adhesive layer 26 is provided on either the surface side S1 of the bonding tape 24 or the one surface side (flat surface side S2) of the base material tape 23 to constitute the tape part 22, the thickness including the adhesive layer 26 is the thickness of the tape part 22, and thus the thickness of the tape part 22, that is, the thickness of the base material tape 23, the thickness of the bonding tape 24, and the thickness of the adhesive layer 25 provided therebetween are designed taking into account the thickness of the adhesive layer 26.
The adhesive layer 26 is preferably provided on one surface (S1 or S2) of the variable-thickness insulating tape 20. In a case in which the adhesive layer 26 is provided on the other main surface F2 serving as the flat surface side S2 of the base material tape, the surface side S2 can be adhered to the outer periphery of the conductor 1. In a case in which the adhesive layer 26 is provided on the bonding tape surface side S1, the surface side S1 can be adhered to the outer periphery of the conductor 1. Although whether the surface S1 or S2 is to be wound on the conductor side can be selected as desired, preferably the variable-thickness insulating tape 20 initially wound is provided with the adhesive layer 26 on the other main surface F2 serving as the flat surface side S2 of the base material tape to wind the flat surface side S2 of that base material tape on the conductor side, and the variable-thickness insulating tape 20 wound in a layer thereon is provided with the adhesive layer 26 on the bonding tape surface side S1 to wind the bonding tape surface side S1 on the conductor side, as illustrated in
It should be noted that the variable-thickness insulating tape 20 can be wound with the adhesive layer 26 being on an outside opposite to the conductor side. In this case, the variable-thickness insulating tape 20 is not firmly adhered to the conductor 1, making it easier to peel the insulating coatings 2, 3 of the variable-thickness insulating tape 20 during end part processing.
The variable-thickness insulating tape 20 is preferably set at a predetermined width corresponding to the diameter of the conductor 1 so as to facilitate being wound around the conductor 1. The width is not particularly limited, but may be about 2 to 15 times the diameter of conductor 1. Large-area sheets fabricated for the variable-thickness insulating tape can be slit and formed to a predetermined width. This makes it possible to obtain the variable-thickness insulating tape 20 for an easy-to-wrap wire especially suitable for the insulated wire 10 for a coil.
The variable-thickness insulating tape 20 can be fabricated by various methods exemplified in
Here, a configuration for making the visibilities of each of the insulating coatings 2, 3 different by changing the respective colors will be described.
The thin insulating coating 2 is mainly constituted by the tape part 21 serving as the thin region B in
With the tape part 22 serving as the thick region A being colored, the thick insulating coating 3 mainly constituted by the tape part 22 can be colored. Specifically, to color the tape part 22 with a simple structure that does not require a complex process, either or both the adhesive layer 25 or/and the bonding tape 24 need only be colored. To color the adhesive layer 25 and the bonding tape 24, a colorant such as red, blue, green, yellow, or orange may be used, but red is preferred in a case in which discrimination is to be improved. The colorant may be any pigment or dye. It should be noted that, at this time, the tape part 21 serving as the thin region B is not colored, and thus the thin insulating coating 2 mainly constituted by the tape part 21 is in a non-colored state.
As mentioned above, by making the colors of the tape part 21 and the tape part 22 different, it is possible to make the visibilities of the insulating coatings 2, 3 provided on the outer periphery of the conductor 1 different, as illustrated in
The constant-thickness insulating tape 30 is a tape having a constant thickness that, as illustrated in
A material of the constant-thickness insulating tape 30 is preferably the same as that of the base material tape 23 constituting the variable-thickness insulating tape 20 described above. A thickness of the constant-thickness insulating tape 30 is not particularly limited as long as, after being wound, the tape part 21 and tape part 22 are thick enough to ensure the required withstand voltage. For example, the thickness may be about 0.002 to 0.1 mm.
The adhesive layer constituting the constant-thickness insulating tape 30 is provided on one surface of the constant-thickness insulating tape 30. A material of the adhesive layer may 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 provided by being transversely wound with the adhesive layer side being on the inside (side of the variable-thickness insulating tape), and immediately or subsequently adhered by being heated or the like. In this way, the constant-thickness insulating tape 30 can be adhered to the variable-thickness insulating tape 20 positioned therebelow. The thickness of the adhesive layer is also not particularly limited, but may be, for example, about 0.001 to 0.05 mm. It should be noted that, in a case in which the tape part 21 and the tape part 22 differ in color, the constant-thickness insulating tape 30 used is preferably transparent or translucent without coloration.
Next, a winding angle and a winding form will be described with reference to
In a case in which the angle θ2 is a right angle, as illustrated in
In the examples illustrated in
It should be noted that, as illustrated in
An insulated wire 10A of a first embodiment illustrated in
The tape part 21 and tape part 22 of the variable-thickness insulating tape 20 are wound around the conductor 1, thereby constituting the thin insulating coating 2 and the thick insulating coating 3. At this time, a slight step occurs in a portion where an edge portion of the variable-thickness insulating tape 20 switches as illustrated in
In such a configuration, by coloring the tape part 22 constituting the thick insulating coating 3, it is possible to color the portion of the insulating coating 3 and not color the portion of insulating coating 2 in
An insulated wire 10B of a second embodiment illustrated in
The constant-thickness insulating tape 30 is wound on the outer periphery of the variable-thickness insulating tape 20, thereby constituting the thin insulating coating 2 and the thick insulating coating 3. At this time, as illustrated in
An insulated wire 10C of a third embodiment illustrated in
It should be noted that the thick insulating coating 3 is mainly constituted by the tape part 22 of the variable-thickness insulating tape 20, but may be partially constituted by the tape part 21 of the variable-thickness insulating tape 20 (20B) as in an a portion illustrated in
An insulated wire 10D of a fourth embodiment illustrated in
The outermost periphery of the insulated wire 10 may be provided with an insulating outer coating (not illustrated) made of extruded resin, as necessary. This insulating outer coating is provided on the outer periphery of the insulated wire 10 illustrated in
In such a coil 40, the insulating coating 3 of the insulated wire in the area where partial discharge readily occurs is thick, thereby making it possible to, for example, increase the partial discharge starting voltage at a crossing part, and the insulating coating 2 of the insulated wire in the area where partial discharge does not readily occur is thin, thereby making it possible to improve and not worsen the occupancy ratio. These areas are repeatedly provided at a desired interval, and thus, for example, in a case in which the coil is preferably applied as a coil for a three-phase induction motor, the thin insulating coating 2 can be set in the slot conductor part of the motor, and the thick insulating coating 3 can be set in an area where high voltage of the crossing part connecting the slot conductor part of the motor is applied.
In this way, the occupancy ratio of the coil winding can be increased by setting the thin insulating coating 2, which can withstand application of phase voltages, for the insulated wire disposed in the stator slot conductor part. Further, in the case of a three-phase induction motor, because each phase voltage is applied to the stator slot conductor part, the crossing part connecting the stator slot conductor part is brought close to or in contact with the crossing part of another phase, and an interphase voltage, specifically a line voltage (√3 times the phase voltage) of the other phase is applied to the crossing part. As a result, although partial discharge is likely to occur at the crossing part, by setting the thick insulating coating 3 for the crossing part connecting the stator slot conductor part to which line voltage is applied, it is possible to increase the partial discharge starting voltage at the crossing part.
At this time, the thin insulating coating 2 of the insulated wire 10 and the thick insulating coating 3 of insulated wire 10 are configured with different visibilities so as to support each arrangement, thereby making it possible to clearly distinguish the insulating coatings 2, 3 from each other, improving arrangement workability.
A method of manufacturing the variable-thickness insulating tape 20 according to the present invention is a method of manufacturing a tape repeatedly provided with the thin portion 21 and the thick portion 22 and, while not particularly limited, examples thereof include the methods illustrated in
(a) The method illustrated in
First, as illustrated in
In a case in which the adhesive is a tacky adhesive, temporary adherence is performed by applying pressure and, in a case in which the adhesive is a thermal adhesive, performed by heating along with applying pressure. Further, when both tapes are bonded, an adhesive may be supplied so as to flow between the tapes. Lamination is performed by heat lamination and, for example, temporary adherence can be performed by applying pressure with a heat roll while applying heat.
After temporary adherence, all but the bonding tape 24 is removed, as illustrated in
It should be noted that, when the thin base material tape 23 and the bonding base tape 24′ are temporarily adhered, the base material tape 23 and the bonding base tape 24′ are preferably bonded by temporary adherence as mentioned above. This temporary adherence makes it possible to, after the thin base material tape 23 and the bonding base tape 24′ are bonded overlapping, easily peel the tape by adjusting the pressure and/or heating temperature applied. Further, after the bonding tape 24 is fabricated by temporary adherence, the thin base material tape 23 and the bonding tape 24 can be fully adhered by applying pressure and/or heating.
(b) The method illustrated in
(c) The method illustrated in
(d) The method illustrated in
In this method, first, as illustrated in
Next, as illustrated in
Next, as illustrated in
Lastly, as illustrated in
It should be noted that, in each of the above-described manufacturing methods (a) to (d), a process of bonding the cover tape 27 onto the bonding tape 24 serving as the thick portion 22 via the adhesive layer 25a may be included. In this way, as illustrated in
As described above, the variable-thickness insulating tape 20 according to the present invention can fluctuate in tape thickness in a repetitive mode, and thus is preferably applicable to components and the like in which different characteristics are required at intervals. The variable-thickness insulating tape 20 manufactured by the above-described methods (a) to (d) or the like can be bonded to parts and members, for example, the strength or insulation of the thick portion 22 can be increased compared to the thin portion 21, and usage in various applications can be expected. Moreover, this method has an effect of not requiring man-hours or complex tasks. The manufactured tape can be distributed and sold as a rolled tape roll.
The present invention will now be described in further detail through 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.
The insulated wire of Example 1 is the insulated wire 10A of the first embodiment illustrated in
The variable-thickness insulating tape 20 is a tape obtained by bonding the bonding tape 24 having a thickness of 25 μm and a length of 65 mm to the base material tape 23 having a thickness of 12 μm at an interval of 40 mm via the colored adhesive layer 25 having a thickness of 2 μm. The adhesive layer 26 is provided on the main surface F1 of the variable-thickness insulating tape 20 on the bonding tape surface side S1. The variable-thickness insulating tape 20 is wrapped around the conductor 1 by a half wrap (½ wrap) with the bonding tape surface side S1 being on the conductor 1 side.
In the obtained insulated wire 10A, the tape part 21 serving as the thin insulating coating 2 has a total average thickness of 23 μm including the adhesive layer 26, and the colored tape part 22 serving as the thick insulating coating 3 has a total average thickness of 62 μm including the colored adhesive layer 25 and the adhesive layer 26. The obtained insulated wire 10A has an average diameter of 1.12 mm in a portion in which the insulating coating is thick, and an average diameter of 1.05 mm in a portion in which the insulating coating is thin. The thicknesses and the average diameters are shown in Table 1. By being wound around the conductor 1 with a protruding portion of the bonding tape surface side S1 being on the inside, a surface of the insulated wire 10A becomes a smooth surface, and this is more preferable in a case of use with the insulating coating wrapped around a coil. At this time, an average diameter difference between the portion of the thick insulating coating 3 and the portion of the thin insulating coating 2 of the insulated wire 10A is 0.07 mm and thus, although identification of the insulating coatings 2, 3 is visibly difficult, the thick insulating coating 3 is colored as in this example, thereby making it possible to easily identify the portion of the thick insulating coating 3 and the portion of the thin insulating coating 2 by the different visibilities of the insulating coatings 2, 3.
The insulated wire of Example 2 is the insulated wire 10B of the second embodiment illustrated in
The variable-thickness insulating tape 20 is a tape obtained by bonding the colored bonding tape 24 having a thickness of 25 μm and a length of 65 mm to the base material tape 23 having a thickness of 12 μm at an interval of 40 mm via the colored adhesive layer 25 having a thickness of 2 μm. The adhesive layer 26 is provided on the main surface F2 of the variable-thickness insulating tape 20 on the flat surface side S2 of the base material tape. The variable-thickness insulating tape 20 is wrapped in two layers around the conductor 1 by a half wrap (½ wrap) with the bonding tape surface side S1 being on the conductor 1 side. The constant-thickness insulating tape 30 is a transparent tape provided with an adhesive layer having a thickness of 2 μm on a tape having a thickness of 9 μm. This constant-thickness insulating tape 30 is wrapped in a winding direction opposite to that of the variable-thickness insulating tape 20 by ⅓ wrap with the side of the adhesive layer being on the inside.
In the obtained insulated wire 10B, the tape part 21 serving as the thin insulating coating 2 has a total average thickness of 40 μm including the adhesive layer 26, and the tape part 22 serving as the colored thick insulating coating 3 has a total average thickness of 78 μm including the colored adhesive layer. The obtained insulated wire 10B has an average diameter of 1.16 mm in a portion in which the insulating coating is thick, and an average diameter of 1.08 mm in a portion in which the insulating coating is thin. The thicknesses and the average diameters are shown in Table 1. At this time, the color of the colored tape part 22 serving as the thick insulating coating 3 can be identified through the transparent constant-thickness insulating tape 30. With the thick insulating coating 3 being colored, the insulating coatings 2, 3 have different visibilities, thereby making it possible to easily identify the portion of the thick insulating coating 3 and the portion of the thin insulating coating 2.
The insulated wire of Example 3 is the insulated wire 10C of the third embodiment illustrated in
The variable-thickness insulating tape 20 is a tape obtained by bonding the colored bonding tape 24 having a thickness of 25 μm and a length of 65 mm to the base material tape 23 having a thickness of 12 μm at an interval of 40 mm via the colored adhesive layer 25 having a thickness of 2μm. In the variable-thickness insulating tape 20A initially wound, the adhesive layer 26 is provided on the flat surface side S2 of the base material tape. In the variable-thickness insulating tape 20B wound thereon, the adhesive layer 26 is provided on the bonding tape surface side S1. The variable-thickness insulating tape 20A is wrapped in two layers around the conductor 1 by a half wrap (½ wrap) with the base material tape 23 side being on the conductor 1 side. The variable-thickness insulating tape 20B wound in the opposite direction thereon is wrapped around the conductor 1 by winding in a winding direction opposite to that of the variable-thickness insulating tape 20A by ⅓ wrap with the bonding tape surface side S1 being on the conductor 1 side.
In the obtained insulated wire 10C, the tape part 21 serving as the thin insulating coating 2 has a total average thickness of 43 μm including the adhesive layer, and the colored tape part 22 serving as the thick insulating coating 3 has a total average thickness of 113 μm including the adhesive layer. The obtained insulated wire 10C has an average diameter of 1.23 mm in a portion in which the insulating coating is thick, and an average diameter of 1.09 mm in a portion in which the insulating coating is thin. The thicknesses and the average diameters are shown in Table 1. At this time, the tape part 22 is colored, thereby making it possible to identify the thick insulating coating 3 portion, and easily identify the portion of the thick insulating coating 3 and the portion of the thin insulating coating 2.
The insulated wire 10D of Example 4 is the insulated wire 10D of the fourth embodiment illustrated in
The variable-thickness insulating tape 20 is a tape obtained by bonding the colored bonding tape 24 having a thickness of 25 μm and a length of 65 mm to the base material tape 23 having a thickness of 12 μm at an interval of 40 mm via the colored adhesive layer 25 having a thickness of 2 μm. The adhesive layer 26 is provided on the flat surface side S2 of the base material tape of the variable-thickness insulating tape 20. The variable-thickness insulating tape 20 is wrapped in three layers around the conductor 1 by ⅔ wrap with the base material tape 23 side being on the conductor 1 side. The constant-thickness insulating tape 30 is a tape provided with an adhesive layer having a thickness of 2 μm on a tape having a thickness of 9 μm. This constant-thickness insulating tape 30 is wrapped in a winding direction opposite to that of the variable-thickness insulating tape 20 by ⅓ wrap with the side of the adhesive layer being on the inside.
In the obtained insulated wire 10D, the tape part 21 serving as the thin insulating coating 2 has a total average thickness of 61 μm including the adhesive layer, and the colored tape part 22 serving as the thick insulating coating 3 has a total average thickness of 133 μm including the adhesive layer. The obtained insulated wire 10D has an average diameter of 1.27 mm in a portion in which the insulating coating is thick, and an average diameter of 1.12 mm in a portion in which the insulating coating is thin. The thicknesses and the average diameters are shown in Table 1. At this time, it possible to identify the colored tape part 22 serving as the thick insulating coating 3 through the transparent constant-thickness insulating tape 30, and easily identify the portion of the thick insulating coating 3 and the portion of the thin insulating coating 2.
An insulated wire of Example 5 is the same as the insulated wire 10C of the third embodiment illustrated in
An insulated wire of Example 6 is, after fabrication of the insulated wire 10A of the first embodiment illustrated in
An insulated wire of Example 7 is the insulated wire 10B of the second embodiment illustrated in
The variable-thickness insulating tape 20 having this sandwich structure is constituted by the base material tape 23 having a thickness of 6 μm, the colored bonding tape 24 having a thickness of 25 μm bonded onto the base material tape 23 via the colored adhesive layer 25 having a thickness of 2 μm, and the cover tape 27 having a thickness of 6 μm covering the bonding tape 24 in its entirety via the adhesive layer 25a having a thickness of 2 μm. The constant-thickness insulating tape 30 is a transparent tape provided with an adhesive layer having a thickness of 2 μm on a tape having a thickness of 9 μm. This constant-thickness insulating tape 30 is wrapped in a winding direction opposite to that of the variable-thickness insulating tape 20 by ⅓ wrap with the side of the adhesive layer being on the inside.
This insulated wire has a total average thickness of 43 μm in the thin portion and a total average thickness of 81 μm in the thick portion. The thicknesses and the average diameters are shown in Table 1. At this time, the color of the colored tape part 22 serving as the thick insulating coating 3 can be identified through the transparent constant-thickness insulating tape 30. Thus, the portion of the thick insulating coating 3 and the portion of the thin insulating coating 2 can be easily identified.
Comparative Example 1 is an enameled wire with a baked film of varnish having an insulating coating thickness of 0.04 mm. Comparative Example 2 is two pieces of the same constant-thickness insulating tape 30 as that used in Example 2, each wound by ½ wrap in opposite directions. The thicknesses and the outer diameters are shown in Table 1.
The partial discharge voltages of each insulated wire in Examples 1 to 7 and Comparative Examples 1 and 2 were measured. Each sample was formed into the two-piece twisted shape of JIS C3216-5, and the partial discharge voltage was measured by an XT-350PB39b manufactured by Adphox Co., Ltd, in accordance with IEC60034-18. The results are shown in Table 1.
In the insulated wire of Example 1, the thin portion of the insulating coating is thinner than the coatings of the insulated wires of Comparative Examples 1 and 2, the thick portion of the insulating coating is approximately 1.5 times that of the coatings of the insulated wires of Comparative Examples 1 and 2, and the partial discharge starting voltage increased by 35% with respect to that of Comparative Example 1. In the insulated wire of Example 2, the thin portion of the insulating coating is the same as those of the coatings of the insulated wires of Comparative Examples 1 and 2, the thick portion of the insulating coating is approximately 2 times those of the coatings of the insulated wires of Comparative Examples 1 and 2, and the partial discharge starting voltage increased by 53% with respect to that of Comparative Example 1. In the insulated wire of Example 3, the thin portion of the insulating coating is substantially the same as those of the coatings of the insulated wire of Comparative Examples 1 and 2, the thick portion of the insulating coating is approximately 2.8 times those of the coatings of the insulated wires of Comparative Examples 1 and 2, and the partial discharge starting voltage increased by 87% with respect to that of Comparative Example 1. In the insulated wire of Example 4, the thin portion of the insulating coating is approximately 1.5 times those of the coatings of the insulated wire of Comparative Examples 1 and 2, the thick portion of the insulating coating is approximately 3.3 times those of the coatings of the insulated wire of Comparative Examples 1 and 2, and the partial discharge starting voltage increased by 135% with respect to that of Comparative Example 1. In the insulated wire of Example 5, the thin portion of the insulating coating is approximately 0.87 times those of the coatings of the insulated wires of Comparative Examples 1 and 2, the thick portion of the insulating coating is approximately 1.5 times those of the insulated wires of Comparative Examples 1 and 2, and the partial discharge starting voltage increased by 35% with respect to that of Comparative Example 1. In the insulated wire of Example 6, the thin portion of the insulating coating is approximately 1.8 times those of the coatings of the insulated wire of Comparative Examples 1 and 2, the thick portion of the insulating coating is approximately 2.5 times those of the coatings of the insulated wires of Comparative Examples 1 and 2, and the partial discharge starting voltage increased by 73% with respect to that of Comparative Example 1. In the insulated wire of Example 7, the thin portion of the insulating coating is substantially the same as those of the coatings of the insulated wires of Comparative Examples 1 and 2, the thick portion of the insulating coating is approximately 2 times those of the coatings of the insulated wires of Comparative Examples 1 and 2, and the partial discharge starting voltage increased by 54% with respect to that of Comparative Example 1.
On the other hand, the coating thickness of the insulated wire of Comparative Example 2 is substantially the same as that of the enameled wire with a baked film of varnish having a thickness of about 0.04 mm, which is typical tape-wound insulated wire and the insulated wire of Comparative Example 1. The insulated wire of Comparative Example 2 had about a 20% increase in partial discharge starting voltage compared to the insulated wire of Comparative Example 1.
As described above, it can be seen that the partial discharge starting voltage of the thick portion of the insulating coating is improved in Examples 1 to 7 compared to in Comparative Examples 1 and 2. This thick portion is adopted, for example, in the “crossing part” connecting the stator slot conductor part of the motor, thereby making it possible to increase the partial discharge starting voltage. In particular, for a coil using a fine wire with a conductor having a cross-sectional size of about 1.0 mm φ as in the examples, it is necessary to increase the adhesion of the insulating coating with respect to the conductor and the positioning accuracy of the thick portion of the insulating coating to accommodate the crossing part of the coil. In such a case, the insulated wire of the present invention, with different thicknesses of the insulating coating being repeatedly formed at predetermined intervals, can simplify processes during coil fabrication.
1 Conductor
2 Thin insulating coating
3 Thick insulating coating
3
a Tapered part
3
b Main body part
10, 10A to 10D Insulated wire
19 Boundary line between thick region and thin region
20, 20A, 20B Variable-thickness insulating tape
21 Tape part (Thin portion)
22, 22a, 22b, 22c Tape part (Thick portion)
23 Base material tape
24 Bonding tape
24′ Bonding base tape
24″ Slit bonding tape
25 Adhesive layer
25
a Adhesive layer
26 Adhesive layer
27 Cover tape
30 Constant-thickness insulating tape
31 Overwrapped part
32 Non-overwrapped part
A Thick region
B Thin region
F1 One main surface of base material tape
F2 Other main surface of base material tape
S1 Surface side of bonding tape
S2 Flat surface side of base material tape
L1, L2, L3 Length of thick portion in longitudinal direction
P1, P2, P3 Interval between thick portions
θ1 Winding angle of variable-thickness insulating tape with respect to longitudinal direction of conductor
θ2 Angle of boundary line between thick region and thin region with respect to longitudinal direction of variable-thickness insulating tape
θ3 Angle between boundary line of variable-thickness insulating tape and longitudinal direction of conductor
40 Coil configuration
E1 to E9 Circumferential conductive wire part
PS1 to PS10 Linear conductive wire part
E1M to E9M Circumferential conductive wire front part
KA1 to KA9 Non-step-formation part
E1N to E9N Circumferential conductive wire rear part
SS1, SS2 Bent end part
51 Process tape
52 Adhesive layer (Pressure-sensitive adhesive layer)
53 Cut
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-035619 | Mar 2020 | JP | national |
| 2020-124158 | Jul 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/048544 | 12/24/2020 | WO |
