Insulated electric wire, coil, electric / electronic device, and method for manufacturing electric / electronic device

Abstract

To provide, regarding technology for burning and removing an end coating film with laser light instead of mechanical removal of the end coating film, an insulated electric wire that, without incorporating foreign substances such as transition metal oxide particles into an insulating coating film, enables, by laser light irradiation, sufficient removal of the insulating coating film from a conductor surface within a short time while suppressing soot or resin from remaining on the conductor surface, and to provide a coil using the insulated electric wire, an electric / electronic device including the coil, and a method for producing the electric / electronic device.SOLUTION: An insulated electric wire 1 comprises at least a conductor 10 and an insulating coating layer A including an insulating resin layer disposed in contact with the conductor 10, and, in the insulating coating layer A, the content of an organic solvent having a flash point of 0-50°C and a boiling point of less than 150°C is 500-20000 ppm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an insulated wire, a coil, an electric / electronic device, and a method for manufacturing an electric / electronic device. [Background technology]

[0002] Insulated wires have traditionally been used in electrical devices. In conventional insulated wires, an insulating coating is formed around a conductor by applying and baking a varnish containing, for example, polyamide-imide, polyimide, heat-resistant polyester, or polyester-imide to the conductor. In electrical and electronic devices such as motors and transformers, for example, insulated wires are processed into hairpin-shaped segment coils, which are then inserted into slots in a stator core. The ends of the segment coils (insulated wires) protruding from the stator core are then welded together to form an electrical connection. To perform this welding, the insulating coating (end coating) covering the ends of the segment coils must be removed to expose the conductor. Mechanical cutting methods, such as press working, are known for removing this end coating. However, this cutting method also removes the surface layer of the conductor, reducing the cross-sectional area of ​​the conductor. Furthermore, this method requires the disposal of metal conductor shavings and causes wear on the molds used in press working, resulting in problems with manufacturing efficiency. Instead of mechanically removing the end coating, a technology has been proposed in which the end coating is burned off and removed using a laser beam. For example, Patent Document 1 describes that, in manufacturing a rotating device in which an insulated electric wire is wound around an insulated armature, the insulating coating of the insulated electric wire contains transition metal oxide particles that absorb laser beams and generate heat, so that the insulating coating at the end of the insulated electric wire can be easily removed by irradiating it with a laser beam. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-15907 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology described in Patent Document 1 requires the preparation of a slurry in which a relatively large amount of transition metal oxide particles are uniformly dispersed in a resin varnish prior to the formation of the insulating coating, which limits the improvement of work efficiency. Furthermore, if a large amount of transition metal oxide particles with physical properties different from those of the insulating resin are contained in the insulating coating, there is a concern that the adhesion between the insulating coating and the conductor and the adhesion between the layers that make up the insulating coating may be reduced.

[0005] The present invention relates to a technology for burning and removing an end coating using a laser beam instead of mechanically removing the end coating, and aims to provide an insulated electric wire that enables sufficient removal of an insulating coating from the conductor surface in a short time by irradiation with a laser beam without incorporating foreign matter such as transition metal oxide particles into the insulating coating. Another aim of the present invention is to provide a coil using this insulated electric wire, an electric or electronic device having this coil, and a method for manufacturing this electric or electronic device. [Means for solving the problem]

[0006] The above-mentioned problems of the present inventors can be solved by the following means. [1] An insulated wire comprising at least a conductor and an insulating coating layer A including an insulating resin layer disposed in contact with the conductor, wherein the insulating coating layer A contains 500 to 20,000 ppm of an organic solvent having a flash point of 0 to 50°C and a boiling point of less than 150°C. [2] The insulated wire according to [1], further comprising an insulating coating layer B around the insulating coating layer A, the insulating coating layer B having an organic solvent content of less than 500 ppm. [3] The insulated wire according to [2], wherein the insulating coating layer B is an enamel layer and / or an extruded coating layer. [4] The insulated wire according to any one of [1] to [3], wherein the insulating coating layer A is an enamel layer. [5] The insulated wire according to any one of [1] to [4], wherein the insulating coating layer A has a thickness of 3 to 50 μm. [6] The insulated wire according to any one of [1] to [5], wherein the polymer constituting the insulating coating layer A has an oxygen atom content of 10 atomic % or more. [7] The insulated wire according to any one of [1] to [6], wherein the insulating coating layer A contains polyimide and / or polyamideimide. [8] The insulated wire according to any one of [1] to [7], wherein the conductor contains copper or aluminum. [9] A coil using the insulated wire according to any one of [1] to [8].

[10] [9] An electric or electronic device having the coil according to [9].

[11] The electrical or electronic device according to

[10] , wherein the electrical or electronic device is a transformer.

[12] a step of removing an end coating of the segment of the insulated wire according to any one of [1] to [8] by irradiating it with laser light; a step of processing the segment from which the end coating has been removed into a coil shape to form a segment coil and incorporating the segment coil into a slot of a stator core; a step of electrically connecting the ends of the segment coils by welding them together; and a method for manufacturing electrical and electronic equipment.

[13] [1] to [8], a process of processing a segment of the insulated wire according to any one of the above [1] to [8] into a coil shape to form a segment coil, and incorporating the segment coil into a slot of a stator core; removing an end coating of the segment coil incorporated in the slot of the stator core by irradiating it with laser light; a step of electrically connecting the ends of the segment coils by welding them together; and a method for manufacturing electrical and electronic equipment.

[0007] In the present invention and this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. For example, when it is written as "A to B," the numerical range is "not less than A and not more than B." In the present invention, "ppm" is based on mass.

[0008] In the present invention and this specification, the term "insulating resin layer" refers to a layer formed by a single layer formation process, and a layer formed by a single layer formation process is counted as one layer. For example, an enamel layer (I) formed by applying and baking a resin varnish once is a single insulating resin layer. If an enamel layer (II) is formed on this enamel layer (I) by applying and baking a varnish made of the same or a different resin once, a laminate structure of two insulating resin layers, enamel layers (I) and (II), is obtained. Furthermore, if an extrusion coating layer (III) is formed on the enamel layer (I) by extrusion coating a thermoplastic resin once instead of the enamel layer (II), a laminate structure of two insulating resin layers, enamel layer (I) and extrusion coating layer (III), is obtained. In addition, when a thermoplastic resin is extruded once onto the enamel layer (II) to form the extrusion coating layer (III), the resulting structure is a laminate of three insulating resin layers: the enamel layer (I), the enamel layer (II), and the extrusion coating layer (III). In the present invention and this specification, the term "insulating coating" refers to the entire insulating resin layer that constitutes an insulated wire. In addition, in the present invention and this specification, the term "insulating coating layer" refers to a layer unit consisting of one or more insulating resin layers that constitute the insulating coating. In the present invention and this specification, an "insulating coating" is composed of one or more (preferably two or more) "insulating coating layers," and an "insulating coating layer" is composed of one or more "insulating resin layers." [Effects of the Invention]

[0009] The insulated wire of the present invention allows the insulating coating to be sufficiently removed from the conductor surface by laser light irradiation in a short time, even without incorporating foreign matter such as transition metal oxide particles into the insulating coating. Therefore, coils or electrical / electronic devices using the insulated wire of the present invention have reduced conductor loss, excellent electrical connections, and improved performance. Furthermore, the manufacturing method for electrical / electronic devices of the present invention is a suitable method for manufacturing the above-mentioned electrical / electronic devices of the present invention. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view schematically illustrating an example of the configuration of an insulated wire according to an embodiment of the present invention. [Figure 2] FIG. 4 is a cross-sectional view schematically illustrating an example of the configuration of an insulated wire according to another embodiment of the present invention. [Figure 3] 1 is a schematic perspective view showing a preferred embodiment of a stator used in an electric / electronic device of the present invention. [Figure 4] 1 is a schematic perspective view showing a preferred embodiment of a stator used in an electric / electronic device of the present invention. [Figure 5] 1 is an explanatory diagram schematically illustrating one embodiment of a method for manufacturing an electric / electronic device according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Insulated wire] The insulated wire of the present invention includes at least a conductor and an insulating coating layer A including an insulating resin layer disposed in contact with the conductor. The insulating coating layer A contains an organic solvent having a flash point of 0 to 50°C and a boiling point of less than 150°C, and the content of the organic solvent in the insulating coating layer A is 500 to 20,000 ppm.

[0012] Preferred embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited to the following embodiments except as defined in the present invention. Furthermore, the descriptions of the conductor, resin varnish, insulating resin layer, insulating coating layer, organic solvent, etc., described with reference to the drawings below are not limited to the embodiments shown in the drawings, but are applied as descriptions of the configuration and specific matters of the present invention.

[0013] FIG. 1 is a cross-sectional view schematically illustrating an example of the configuration of an insulated wire 1 according to one embodiment of the present invention. The insulated wire 1 has a conductor 10 and an insulating coating layer A that contacts the conductor 10 and covers the circumferential surface of the conductor 10. The insulating coating layer A may have a single-layer structure consisting of a single insulating resin layer, or a multi-layer structure consisting of two or more insulating resin layers. In the embodiment of FIG. 1, the insulating coating layer A serves as an insulating coating. The insulated wire 1 of this embodiment will be described below, starting with the conductor 10.

[0014] <conductor> Conductor 10 can be a wide variety of conductors commonly used in insulated wires, and is typically a metal conductor. The metal conductor preferably contains copper or aluminum, and copper wire or aluminum wire is preferably used. While conductor 10 shown in FIG. 1 has a rectangular (flat) cross-sectional shape, the cross-sectional shape is not particularly limited and may be, for example, circular. In order to suppress partial discharge from the corners, the rectangular conductor 10 preferably has four chamfered corners (with a radius of curvature r) as shown in Fig. 1. The radius of curvature r is preferably 0.6 mm or less, and more preferably 0.2 to 0.4 mm. The size of the conductor 10 is not particularly limited. In the case of a rectangular conductor, the width (long side) of the rectangular cross-sectional shape is preferably 1 to 5 mm, more preferably 1.4 to 4.0 mm, and the thickness (short side) is preferably 0.4 to 3.0 mm, more preferably 0.5 to 2.5 mm. The ratio of the width (long side) to the thickness (short side) (thickness:width) is preferably 1:1 to 1:4. In the case of a conductor with a circular cross-sectional shape, the diameter is preferably 0.3 to 3.0 mm, more preferably 0.4 to 2.7 mm.

[0015] <Insulating coating layer A> The insulating coating layer A may be an enamel layer formed by applying a resin varnish containing an insulating resin (insulating polymer) onto the conductor 10 and baking it, or an extrusion coating layer formed by extrusion coating a thermoplastic resin, with the enamel layer being preferred. When the insulating coating layer A is an enamel layer, a thermoplastic resin such as a thermosetting resin or polyetherimide may be used to form the enamel layer, with the enamel layer being preferably formed by curing a thermosetting resin. Examples of thermosetting resins used to form the enamel layer include polyimide (PI), polyurethane, polyamideimide (PAI), thermosetting polyester (PEst), H-type polyester (HPE), polybenzimidazole, polyesterimide (PEsI), melamine resin, and epoxy resin, and one or more of these may be used. Among these, polyimide, polyamideimide, H-type polyester, and polyesterimide are preferred.

[0016] The polyimide is not particularly limited, and conventional polyimides such as wholly aromatic polyimides and thermosetting aromatic polyimides can be used. For example, commercially available products (trade name: U-imide (manufactured by Unitika Ltd.) and trade name: U-varnish (manufactured by Ube Industries, Ltd.)) can be used. Alternatively, a polyimide obtained by using a polyamic acid solution obtained by reacting an aromatic tetracarboxylic dianhydride with an aromatic diamine in a polar solvent in a conventional manner and imidizing it by heat treatment during baking during coating can be used.

[0017] The above-mentioned H-type polyester refers to an aromatic polyester in which the resin is modified by adding a phenolic resin or the like, and has a heat resistance class of H. An example of a commercially available H-type polyester is Isonel 200 (manufactured by Schenectady International, USA).

[0018] The organic solvent of the resin varnish used to form the insulating coating layer A, which is an enamel layer, can be any of a wide variety of organic solvents commonly used in this type of resin varnish. Examples include amide solvents such as N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), and N,N-dimethylformamide (DMF), as well as organic solvents with a boiling point of 150°C or higher, such as dimethyl sulfoxide (DMSO). From the perspective of varnish stability due to hydrogen bonding with the resin, the organic solvent preferably contains an aprotic solvent, and more preferably contains DMAc and / or NMP.

[0019] In the present invention, the resin varnish contains a desired amount of an organic solvent having a flash point of 0 to 50°C and a boiling point of less than 150°C (hereinafter referred to as organic solvent a). By forming the insulating coating layer A using such a resin varnish, the insulating coating layer A can contain organic solvent a at a content of 500 to 20,000 ppm. Note that organic solvent a is liquid at 25°C and 1 atmosphere. The flash point of organic solvent a is preferably 5 to 45°C, more preferably 10 to 40°C. The boiling point of organic solvent a is preferably 140°C or lower, more preferably 130°C or lower, and even more preferably 120°C or lower. One organic solvent a may be used alone, or two or more organic solvents a may be used in combination. The boiling point of organic solvent a is preferably 70°C or higher, more preferably 80°C or higher, more preferably 90°C or higher, and even preferably 100°C or higher. The boiling point range of organic solvent a is preferably 70 to 150°C, more preferably 80 to 140°C, more preferably 90 to 130°C, and even more preferably 100 to 120°C. The flash point is the flash point determined by the tag-closed method based on JIS K 2265-1 (2007). The boiling point is the boiling point at an external pressure of 0.1 MPa (1 atmosphere). Specific examples of the organic solvent a include lower alcohols such as methanol, ethanol, butanol, and pentanol, and aromatic hydrocarbons such as xylene and toluene, and one or more of these can be used. The organic solvent a is preferably an alcohol, and more preferably a monoalcohol. The content of the organic solvent a in the resin varnish for forming the insulating coating layer A is preferably 0.1 to 50 mass %, more preferably 0.5 to 20 mass %, and even more preferably 1 to 10 mass %.

[0020] The content of the organic solvent a in the insulating coating layer A is preferably 600 to 10,000 ppm, more preferably 650 to 8,000 ppm, even more preferably 700 to 6,000 ppm, still more preferably 750 to 4,000 ppm, and even more preferably 800 to 2,000 ppm.

[0021] The thickness of the insulating coating layer A is preferably 100 μm or less, more preferably 60 μm or less, even more preferably 50 μm or less, and even more preferably 40 μm or less. The thickness of the insulating coating layer A is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, and even more preferably 10 μm or more. The thickness of the insulating coating layer A is preferably in the range of 1 to 100 μm, more preferably 3 to 60 μm, more preferably 3 to 50 μm, even more preferably 5 to 40 μm, and also preferably 10 to 40 μm.

[0022] When the insulating coating layer A is an enamel layer and has a thickness of, for example, about 10 μm or more, the insulating coating layer A usually has a multi-layer structure of two or more layers. That is, it is a layer formed by applying and baking a resin varnish two or more times. In the present invention, the content of organic solvent a in the insulating coating layer A being 500 to 20,000 ppm means that the content of organic solvent a is 500 to 20,000 ppm in all insulating resin layers constituting the insulating coating layer A.

[0023] The insulating coating layer A contains the organic solvent a in the above-mentioned specific amount, which significantly improves the efficiency of insulating coating removal by laser light irradiation. Although the reason for this is unclear, one possible reason is that the organic solvent a has a low flash point of 0 to 50°C and a relatively low boiling point of less than 150°C, which, together with oxygen and other substances generated from the resin decomposed by the heat applied during laser light irradiation, promotes the spread of fire in the resin.

[0024] In addition to the organic solvent a, the insulating coating layer A usually contains other organic solvents contained in the varnish (organic solvents other than the organic solvent a, for example, organic solvents typically used in the above-mentioned resin varnishes). The content of the other organic solvents in the insulating coating layer A is preferably 1,000 to 20,000 ppm, more preferably 2,000 to 18,000 ppm, even more preferably 3,000 to 15,000 ppm, and still more preferably 4,000 to 13,000 ppm. In the insulating coating layer A, the total content of organic solvent a and organic solvents other than organic solvent a (total content of organic solvents in the insulating coating layer A) is preferably 2000 to 40000 ppm, more preferably 3000 to 30000 ppm, even more preferably 4000 to 20000 ppm, and still more preferably 5000 to 15000 ppm.

[0025] In the above description, the insulating coating layer A is an enamel layer, but the insulating coating layer A may be an extrusion coating layer. In this case, the insulating coating layer A can be formed by extrusion coating the conductor surface with an organic solvent containing at least organic solvent a in the thermoplastic resin to be extrusion coated. As the thermoplastic resin from which the extrusion coating layer is formed, a wide range of thermoplastic resins typically used as insulating resin layers for insulated wires can be used. For example, general-purpose engineering plastics such as polyamide (PA) (nylon), polyacetal (POM), polycarbonate (PC), polyphenylene ether (including modified polyphenylene ether), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and ultra-high molecular weight polyethylene, as well as polysulfone (PSF), polyethersulfone (PES), polyphenylene sulfide (PPS), polyarylate (U polymer), polyetherketone (PEK), polyaryletherketone (PAEK), tetrafluoroethylene-ethylene copolymer (ETFE), polyetheretherketone (PEEK) (modified polyether ether) Examples of suitable resins include super engineering plastics such as tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers (PFA), polytetrafluoroethylene (PTFE), thermoplastic polyimide resins (TPI), and liquid crystal polyesters; polymer alloys based on polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); and polymer alloys containing the above engineering plastics, such as ABS / polycarbonate, nylon 6,6, aromatic polyamide resins (aromatic PA), polyphenylene ether / nylon 6,6, polyphenylene ether / polystyrene, and polybutylene terephthalate / polycarbonate. These resins may be used alone or in combination. The thermoplastic resin preferably includes at least one of polyether ether ketone (PEEK), polyphenylene sulfide (PPS), polyethylene terephthalate (PET), and nylon 6,6 (66 nylon, PA66).

[0026] As the polyether ether ketone, for example, commercially available products such as trade name: KetaSpire KT-820 (manufactured by Solvay Specialty Polymers) and trade name: PEEK450G (manufactured by Victrex Japan) can be used.

[0027] The insulating coating layer A preferably has an oxygen atom content (the ratio of the number of oxygen atoms to the total number of constituent atoms of the polymer, also referred to as the oxygen atomic ratio) of 10 atomic % or more (preferably 10.5 atomic % or more) in the polymer constituting the insulating coating layer A. An oxygen atomic ratio of 10 atomic % or more promotes thermal decomposition of the insulating coating layer A by laser peeling, as described below, and reduces the likelihood of soot remaining. Many polyimides or polyamideimides have a structure with an oxygen atomic ratio of 10 atomic % or more, and are preferred as constituent materials for the insulating coating layer A. Therefore, the insulating coating layer A preferably contains polyimide and / or polyamideimide, and more preferably consists of polyimide and / or polyamideimide. The oxygen atom content in the polymer constituting the insulating coating layer A is usually 15 atomic % or less, and preferably 14 atomic % or less.

[0028] FIG. 2 is a cross-sectional view schematically illustrating an exemplary configuration of an insulated wire 2 according to another embodiment of the present invention. The insulated wire 2 includes a conductor 20, an insulating coating layer A that contacts the conductor 20 and coats the outer peripheral surface of the conductor 20, and an insulating coating layer B that coats the outer peripheral surface of the insulating coating layer A. The conductor 20 is the same as the conductor 10 described in the embodiment of FIG. 1, and the preferred embodiment is also the same. The insulating coating layer A is the same as the insulating resin layer A described in the embodiment of FIG. 1, and the preferred embodiment is also the same. The insulating coating layer B may have a single-layer structure like the insulating coating layer A, or may have a multi-layer structure in which two or more insulating resin layers are laminated. In the embodiment of FIG. 2, the insulating coating layer A and the insulating coating layer B together form an insulating coating. The insulating coating layer B, which is characteristic of this embodiment, will be described below.

[0029] <Insulating coating layer B> The insulating coating layer B is not particularly limited as long as the content of organic solvent a is less than 500 ppm, and may be an enamel layer, an extruded coating layer, or a combination of an enamel layer and an extruded coating layer. The content of organic solvent a in the insulating coating layer B is preferably 400 ppm or less, more preferably 300 ppm or less, even more preferably 200 ppm or less, and even preferably 100 ppm or less. It is also preferable that the insulating coating layer B does not contain organic solvent a. That is, while the insulating coating layer A is formed using a resin varnish or extruded coating material containing organic solvent a, the insulating coating layer B does not need to contain organic solvent a. Therefore, the organic solvent used in the resin varnish or the like used to form the insulating coating layer B can be the same as the organic solvent typically used in resin varnishes.

[0030] When the insulating coating layer B is an extruded coating layer, it can be formed by extruding a thermoplastic resin onto the outer peripheral surface of the insulating coating layer A, for example, using a co-extruder. The extruded coating layer may be formed using a thermoplastic resin and an organic solvent or the like. For example, the thermoplastic resin described for the extruded coating layer of the insulating coating layer A can be used as this thermoplastic resin.

[0031] The insulating coating layer B may be formed by applying and baking a resin varnish onto the insulating coating layer A. In this case, the insulating coating layer B may be an enamel layer made of a thermoplastic resin or an enamel layer formed by curing a thermosetting resin, preferably an enamel layer formed by curing a thermosetting resin. Examples of resins used to form the enamel layer include the resins described for the enamel layer of the insulating coating layer A.

[0032] The step of forming the insulating coating layer B itself can employ a general method for forming an insulating resin layer for an insulated wire.

[0033] The thickness of the insulating coating layer B is not particularly limited and can be, for example, 1 to 200 μm, or may be 3 to 150 μm, or preferably 5 to 120 μm. When the insulating coating layer B is an enamel layer, the thickness is preferably 5 to 50 μm, or preferably 5 to 40 μm, or preferably 10 to 30 μm.

[0034] Furthermore, the ratio (D2 / D1) of the thickness of the insulating coating layer A (D2) to the total thickness (D1) of the insulating coating layer A and the insulating coating layer B is preferably 0.01 to 0.7, more preferably 0.02 to 0.7, more preferably 0.1 to 0.7, more preferably 0.15 to 0.6, and even more preferably 0.2 to 0.5.

[0035] The resin varnish, insulating resin layer, and insulating coating layer used in the present invention may contain various additives, such as a bubble-nucleating agent, an antioxidant, an antistatic agent, an ultraviolet inhibitor, a light stabilizer, a fluorescent brightener, a pigment, a dye, a compatibilizer, a lubricant, a reinforcing agent, a flame retardant, a crosslinking agent, a crosslinking aid, a plasticizer, a thickener, a viscosity reducer, and an elastomer, to the extent that the additives do not affect the properties.

[0036] [Insulated wire manufacturing method] The insulated wire of the present invention can be produced by forming an insulating coating layer A on the outer periphery of a conductor and, if necessary, sequentially forming an insulating coating layer B. The method of forming an enamel layer by applying and baking a resin varnish and the method of forming an extrusion coating layer are themselves widely known in the technical field of insulated wires, and the insulated wire of the present invention can be obtained by appropriately applying a conventional method, except for forming the insulating coating layer A so as to leave a specific amount of organic solvent a remaining.

[0037] In the present invention, in order to allow a specific amount of organic solvent a to remain in the formed insulating coating layer A, the baking conditions of the resin varnish and the like can be adjusted as appropriate. For example, the content (residual amount) of organic solvent A increases when the passage time or the oven temperature is reduced among the baking conditions. Furthermore, by using a baking oven with a shorter oven length, the heating time is shortened even at the same set temperature, and the content of organic solvent A can be effectively adjusted to the desired amount. Such methods for controlling the residual solvent amount are widely known to those skilled in the art, and the target residual solvent amount can be controlled by appropriately adjusting the production conditions.

[0038] [Uses of insulated wire] The insulated wire of the present invention can be preferably processed into a coil and used in fields requiring voltage resistance and heat resistance, such as various electrical devices. The electrical and electronic devices using this coil are not particularly limited. A preferred embodiment of such an electrical and electronic device is a transformer. Another example is a rotating device equipped with a stator 30 shown in FIG. 3 (e.g., a drive motor for a hybrid or electric vehicle). This rotating device can have the same configuration as a typical rotating device, except that it is equipped with a stator 30. The stator 30 can have the same configuration as a normal stator, except that the wire segments 34 (segment coils 34) are formed from the insulated wire of the present invention. That is, the stator 30 has a stator core 31 (stator core 31) and, for example, as shown in FIG. 3 , wire segments 34 made from the insulated wire of the present invention are inserted into slots 32 of the stator core 31, and coils 33 formed by electrically connecting open ends 34 a. Here, the wire segments 34 may be inserted into the slots 32 individually, but preferably, as shown in FIG. 4 , a pair of wire segments 34 are inserted into the slots 32. In this stator 30, the coils 33 are formed by alternately connecting the open ends 34 a of the wire segments 34 bent as described above, and are inserted into the slots 32 of the stator core 31. At this time, the open ends 34 a of the wire segments 34 may be connected before insertion into the slots 32, or the open ends 34 a of the wire segments 34 may be bent and connected after insertion into the slots 32.

[0039] [Manufacturing methods for electrical and electronic equipment] The method for manufacturing electrical and electronic devices of the present invention includes the steps of segmenting the insulated wire of the present invention described above and removing the end coating of the segments by irradiating them with laser light, coiling the segments from which the end coating has been removed to form segment coils and fitting them into slots in a stator core, and welding the ends of the segment coils from which the coating has been removed to electrically connect them. An example of each of these steps, including the steps before and after, will be described with reference to the drawings.

[0040] 5 is an explanatory view schematically illustrating one embodiment of the method for manufacturing an electric / electronic device of the present invention. Note that the method for manufacturing an electric / electronic device of the present invention is not limited to the following embodiment except as defined in the present invention.

[0041] Figure 5 shows the insulated wire shortening process (segmenting process), the coating removal process for removing the coating from the ends of the resulting segment coils, the assembly process for fitting these segment coils into slots in the stator core, and the welding and powder coating process for welding the ends of the segment coils from which the coating has been removed and powder coating the welded joints (insulating coating). Each of these processes is explained below.

[0042] <Shortening process> In the shortening step, the insulated wire 1 wound around the roller R is cut at predetermined intervals, thereby obtaining an insulated wire 1 shortened to a predetermined dimension.

[0043] <Coating removal process> In the coating removal step, the insulating coating at the end of the shortened insulated wire 1 is burned (thermally decomposed) by irradiation with laser light and removed to expose the conductor 10 at the end. Methods for removing insulating coating by irradiation with laser light are disclosed in, for example, Japanese Patent Application Laid-Open Nos. 6-38330, 2001-309521, and 2005-285755. The coating removal step of the present invention may be performed using a laser device. This laser device may have, for example, a laser oscillator and be configured to be capable of outputting laser light with a power of several kW. Alternatively, for example, the laser device may have multiple semiconductor laser elements therein and be configured to be capable of outputting multimode laser light with a power of several kW as the total output of the multiple semiconductor laser elements. The laser device may have various laser light sources such as a fiber laser, a YAG (Yttrium Aluminum Garnet) laser, a disk laser, etc. The laser device may output a continuous wave of laser light or a pulse of laser light.

[0044] In the present invention, the insulating coating layer A of the insulated wire 1 contains 500 to 20,000 ppm of an organic solvent a having a flash point of 0 to 50°C and a boiling point of less than 150°C, which enables the insulating coating to be sufficiently removed from the surface of the conductor 10 in a short time. Furthermore, the reduction in the cross-sectional area of ​​the conductor 10 caused by excessive removal of the surface layer of the conductor 10, which has been a problem in conventional mechanical cutting methods, is suppressed. Furthermore, no shavings of the conductor 10 are generated, and there is no need to worry about wear on the mold used in press processing. Therefore, it is possible to effectively improve the performance and manufacturing efficiency of coils and electrical / electronic devices using the insulated wire.

[0045] <Assembly process> In the assembly process, the insulated wire 1, from which the insulating coating has been removed at the end, is bent into a hairpin shape to produce the segment coil 34. Next, the segment coil 34 is inserted into the slot 32 of the stator core 31, and the segment coil 34 protruding from the surface of the stator core 31 is twisted.

[0046] <Welding and powder coating process> In the welding and powder coating process, the open end 34a of one segment coil 34 is welded and electrically connected to the open end 34a of the other segment coil 34. Next, an insulating powder coating is applied to the welded area to coat the welded area with an insulating material.

[0047] Through the above steps, the desired electric / electronic device can be obtained. The order of the coating removal step and the assembly step may be reversed. That is, after the shortening step, the insulated wire segments may be processed into coils to form segment coils, which may then be assembled into slots in the stator core, and the coating on the end of the segment coil may then be removed by irradiating it with laser light. In relation to the above-described embodiments, the present invention provides the following method for manufacturing an electric / electronic device.

[0048] a step of removing a coating on an end of the segment of the insulated wire of the present invention by irradiating the segment with laser light; a step of processing the segment from which the end coating has been removed into a coil shape to form a segment coil and incorporating the segment coil into a slot of a stator core; a step of electrically connecting the ends of the segment coils by welding them together; and a method for manufacturing electrical and electronic equipment.

[0049] a step of processing the segment-shaped insulated wire of the present invention into a coil shape to form a segment coil and incorporating the segment coil into a slot of a stator core; removing an end coating of the segment coil incorporated in the slot of the stator core by irradiating it with laser light; a step of electrically connecting the ends of the segment coils by welding them together; and a method for manufacturing electrical and electronic equipment. [Example]

[0050] The present invention will be described in more detail based on examples, but the present invention is not limited to the following examples.

[0051] [Making insulated wire] Example 1 In Example 1, an insulated wire 2 shown in FIG. 2 was produced. The conductor 10 was a copper wire with a rectangular cross section. To form the insulating coating layer A, a die similar in shape to the shape of the insulating coating layer A to be formed on the conductor 10 was used. The surface of the conductor 10 was coated with polyimide resin varnish using the die, and the conductor was passed through a 10-m long hot air circulating furnace set at an internal temperature of 500°C at a speed that resulted in a passage time of 10 to 20 seconds. This process was repeated three times to form an insulating coating layer A with a thickness of 15 μm. To form insulating coating layer B, a die similar in shape to the insulating coating layer B to be formed on insulating coating layer A was used. Polyamide-imide resin varnish was coated onto the surface of insulating coating layer A using the die, and the layer was passed through a 10-m long hot air circulating furnace set at an internal temperature of 500°C at a speed that resulted in a passage time of 10 to 20 seconds. This process was repeated three times to form insulating coating layer B with a thickness of 15 μm. In Example 1, the polyimide resin varnish used to form the insulating coating layer A was based on a commercially available polyimide resin varnish (manufactured by Unitika Ltd., product name: U-imide), to which n-butanol was added as organic solvent a. The polyamideimide resin varnish used to form the insulating coating layer B was a commercially available polyamideimide resin varnish (manufactured by Showa Denko Materials KK, trade name: HI406). In Example 1, the ratio of the thickness (D2) of the insulating coating layer A to the total thickness (D1) of the insulating coating layer A and the insulating coating layer B (film thickness ratio, D2 / D1) was 0.50.

[0052] <Example 2> Insulated wire 2 was produced in the same manner as in Example 1, except that the total thickness (D1) of insulating coating layer A and insulating coating layer B was not changed, and the ratio (D2 / D1) of the thickness of insulating coating layer A (D2) to D1 was set to 0.20.

[0053] Example 3 An insulated wire 2 was produced in the same manner as in Example 2, except that the commercially available polyimide resin varnish used to form the insulating coating layer A was changed to the commercially available polyamideimide resin varnish, and the commercially available polyamideimide resin varnish used to form the insulating coating layer B was changed to the commercially available polyimide resin varnish. Note that n-butanol was mixed into the polyamideimide resin varnish as organic solvent a.

[0054] Example 4 Insulated wire 2 was produced in the same manner as in Example 3, except that the coating and baking process for forming insulating coating layer A was repeated six times to make the thickness of insulating coating layer A 30 μm, and insulating coating layer B was an extruded coating layer with a thickness of 100 μm. The ratio of the thickness (D2) of the insulating coating layer A to the total thickness (D1) of the insulating coating layer A and the insulating coating layer B (film thickness ratio, D2 / D1) was set to 0.23. The extrusion coating layer was formed using an extruder with a 30 mm full flight screw, L / D = 20, and a compression ratio of 3. Polyether ether ketone (PEEK) (manufactured by Solvay, product name: KT-800) was used as the thermoplastic resin, and extrusion coating was performed using an extrusion die at 370°C (extrusion die temperature) so that the outer shape of the cross section of the extrusion coating layer would be similar to the shape of the conductor 10, forming an insulating coating layer B with a thickness of 100 μm on the outside of insulating coating layer A.

[0055] <Example 5> An insulated wire 2 was produced in the same manner as in Example 4, except that the commercially available polyamideimide resin varnish was changed to a polyetherimide resin varnish and the thickness of the insulating coating layer A was set to 10 μm. The ratio (D2 / D1) of the thickness of the insulating coating layer A (D2) to the total thickness (D1) of the insulating coating layer A and the insulating coating layer B was set to 0.09. To form the insulating coating layer A, polyetherimide (PEI) (product name: Ultem 1010, manufactured by Sabic Innovative Plastics) was dissolved in N-methyl-2-pyrrolidone (NMP), and n-butanol was further added as organic solvent A to prepare a polyetherimide resin varnish. Next, this varnish was coated onto the surface of the conductor 10 using a die similar in shape to the conductor 10, and the conductor was passed through a baking furnace with a length of 10 m and an internal temperature of 500°C at a speed that resulted in a passage time of 15 seconds, forming an insulating coating layer A made of polyetherimide with a thickness of 10 μm.

[0056] <Comparative Example 1> An insulated wire was produced in the same manner as in Example 4, except that the insulating coating was simply an extruded PEEK coating layer (thickness: 100 μm).

[0057] <Comparative Example 2> An insulated wire was produced in the same manner as in Example 5, except that in forming the insulating coating layer A in Example 5, the organic solvent a was not mixed into the polyetherimide resin varnish.

[0058] <Comparative Example 3> An insulated wire was produced in the same manner as in Example 4, except that a commercially available polyamideimide resin varnish was used as is (without adding organic solvent a) to form the insulating coating layer A.

[0059] [Measurement of organic solvent content in insulating coating layer A] For the insulated wires according to the examples and comparative examples, insulating coating layer B was peeled off from insulating coating layer A using a blade, and then insulating coating layer A was peeled off from conductor 10 using the blade. 3 mg of the peeled insulating coating layer A was accurately measured and thermally decomposed at a pyrolysis temperature of 400°C. The evaporated organic solvents were measured by gas chromatography to determine the types of organic solvents and their contents. The results are shown in Table 1.

[0060] [Laser peeling test] The insulated wires of the examples and comparative examples were cut into 70 mm long segments, and the insulating coating covering the ends of the segments was removed by irradiating them with infrared laser light having a wavelength of 1070 nm (output: 300 W, speed: 1500 mm / s). The time required for the insulating coating to be completely removed from the end of the insulated wire to within 10 mm was measured. The results are shown in Table 1.

[0061] [Table 1]

[0062] (Note to Table 1) In Table 1, "PAI," "PI," "PEEK," and "PEI" mean "polyamideimide," "polyimide," "polyetheretherketone," and "polyetherimide," respectively. "Film thickness ratio" in Table 1 means the ratio (D2 / D1) of the thickness of the lower layer (D2) to the total thickness (D1) of the lower layer and upper layer.

[0063] As shown in Table 1, the time required to remove the insulating coating of the insulated wire according to the comparative example by laser light irradiation was 18 to 20 seconds, whereas the time required to remove the insulating coating of the insulated wire 2 according to the example by laser light irradiation was 0.5 to 1 second. This result shows that the time required to remove the insulating coating of the insulated wire 2 according to the example by laser light irradiation is significantly reduced.

[0064] [Measuring carbon atom concentration] Next, for the insulated wire segments according to the examples and comparative examples subjected to the laser peeling test, the carbon atom concentration (atomic %, at %) of the conductor surface peeled by laser light irradiation was measured. Specifically, the conductor surface was analyzed by energy dispersive X-ray spectroscopy (EDS), and the carbon atom concentration was calculated by converting the total number of carbon atoms, oxygen atoms, and copper atoms present on the conductor surface to 100%. The measurement results are shown in Table 2. (Criteria for determining carbon atom concentration) ◎: Carbon atom concentration is less than 25% ○: Carbon atom concentration is 25% or more and less than 50% △: Carbon atom concentration is 50% or more

[0065] [Welding strength test] For the insulated wires according to the examples and comparative examples that underwent the laser peeling test, the conductors at the exposed ends of two segments were welded together, and the weld strength was measured. The test results are shown in Table 2. The welding was performed by irradiating a laser beam. In measuring the welding strength, both ends of two welded insulated wires were gripped and pulled in opposite directions, and the load (N) was measured when the weld broke. (Weld strength test criteria) △: Weld strength is less than 500N 〇: Welding strength is 500N or more but less than 700N ◎: Welding strength is 700N or more

[0066] [Table 2]

[0067] As shown in Table 2, in the insulated wires 2 according to Examples 1 to 4, in which the oxygen atomic ratio of the resin constituting the insulating coating layer A is 10 atomic % or more and the insulating coating layer A contains a specific amount of organic solvent a, it was found that the soot generated by laser peeling was prevented from remaining on the conductor surface, and the welding strength was further increased. [Explanation of symbols]

[0068] 1, 2...insulated wire, 10, 20...conductor, A, B...insulating coating layer.

Claims

1. An insulated wire comprising at least a conductor and an insulating coating layer A including an insulating resin layer disposed in contact with the conductor, wherein the insulating coating layer A contains 500 to 20,000 ppm of an organic solvent having a flash point of 0 to 50°C and a boiling point of less than 150°C.

2. 2. The insulated wire according to claim 1, further comprising an insulating coating layer B around the insulating coating layer A, the insulating coating layer B having an organic solvent content of less than 500 ppm.

3. 3. The insulated wire according to claim 2, wherein the insulating coating layer B is an enamel layer and / or an extruded coating layer.

4. 4. The insulated wire according to claim 3, wherein the insulating coating layer A is an enamel layer.

5. 5. The insulated wire according to claim 4, wherein the insulating coating layer A has a thickness of 3 to 50 μm.

6. 6. The insulated wire according to claim 5, wherein the polymer constituting the insulating coating layer A has an oxygen atom content of 10 atomic % or more.

7. The insulated wire according to claim 6 , wherein the insulating coating layer A contains polyimide and / or polyamideimide.

8. 8. The insulated wire of claim 7, wherein the conductor comprises copper or aluminum.

9. A coil using the insulated wire according to any one of claims 1 to 8.

10. An electric or electronic device comprising the coil according to claim 9.

11. The electrical or electronic device according to claim 10, wherein the electrical or electronic device is a transformer.

12. a step of removing an end coating of the insulated electric wire segment according to any one of claims 1 to 8 by irradiating it with laser light; a step of processing the segment from which the end coating has been removed into a coil shape to form a segment coil and incorporating the segment coil into a slot of a stator core; a step of electrically connecting the ends of the segment coils by welding them together; A method for manufacturing electrical and electronic equipment, including

13. A step of processing the segment of the insulated wire according to any one of claims 1 to 8 into a coil shape to form a segment coil and incorporating it into a slot of a stator core; removing an end coating of the segment coil incorporated in the slot of the stator core by irradiating it with laser light; a step of electrically connecting the ends of the segment coils by welding them together; A method for manufacturing electrical and electronic equipment, including

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