Insulated wire, electrical and electronic equipment, method for manufacturing insulated wire, and method for manufacturing electrical and electronic equipment.

Abstract

To provide an insulated wire capable of sufficiently improving adhesiveness of a conductor exposed part and an insulation coating layer when ends are welded to each other and next the insulation coating layer is provided in a periphery of the conductor exposed part, the insulated wire including the ends in which a conductor is exposed by substantially removing only an end coating, and a manufacturing method of the insulated wire.SOLUTION: An insulated wire 1 comprises a conductor 10 and an insulation coating A covering a periphery of the conductor 10. The insulated wire 1 includes an end 11 in which the conductor 10 is exposed. A value (S2 / S1) of a ratio of a conductor cross-sectional area (S2) of the end 11 where the conductor 10 is exposed with respect to a conductor cross-sectional area (S1) other than the end 11 where the conductor 10 is exposed is 0.95 or more, and an arithmetic average height Sa of a conductor surface in the end 11 where the conductor 10 is exposed ranges from 1.0 to 5.0 μm. The present invention relates to the insulated wire 1, a manufacturing method of the insulated wire 1, an electric / electronic apparatus using the insulated wire 1, and a manufacturing method of the electric / electronic apparatus.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to insulated wires, electrical and electronic equipment, methods for manufacturing insulated wires, and methods for manufacturing electrical and electronic equipment. [Background technology]

[0002] Insulated wires have traditionally been used in electrical and electronic equipment. For example, insulated wires are known in which a single or multi-layer enamel layer is formed around a conductor by applying and baking a varnish containing polyamide-imide, polyimide, heat-resistant polyester, or polyester-imide to the conductor. Insulated wires are also known in which an insulating film is formed by extruding a thermoplastic resin around the conductor. Furthermore, insulated wires are also known in which an enamel layer is formed around the conductor, and then a thermoplastic resin is extruded around this enamel layer to form an insulating film consisting of an enamel layer and an extruded coating layer. In electrical and electronic equipment such as motors and transformers, for example, insulated wires are processed into hairpin shapes to form segment coils, which are then pushed into slots in a stator core. The ends of the segment coils (insulated wires) protruding from the stator core are then welded together to create an electrical connection. The area around the welded joint is then treated with an insulating coating such as powder coating or varnish to form an insulating coating layer. To perform this welding, it is necessary to remove the insulating film (end coating) covering the ends of the segment coils to expose the conductors at those ends. A known method for removing this end coating is to mechanically cut it off by pressing. However, this cutting method has the problem of removing not only the insulating film but also a large portion of the conductor surface, thus reducing the conductor cross-sectional area. Furthermore, it requires the disposal of metal conductor shavings and causes wear on the molds used in pressing, leading to problems in terms of manufacturing efficiency. Instead of mechanically removing the end coating, a technique has been proposed to remove the end coating by burning it using laser light. For example, Patent Document 1 describes that when manufacturing a rotating electric machine in which an insulated wire is wound around an insulated armature, by incorporating particles of transition metal oxide that absorb laser light and generate heat into the insulating coating of the insulated wire, the insulating coating at the end of the insulated wire can be easily removed by laser irradiation. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2010-15907 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] As described above, after welding the exposed conductors together at the ends of the segment coils protruding from the stator core, an insulating coating layer is formed on the exposed conductor portion (exposed conductor portion) by insulating paint. The inventors have investigated the adhesion between this exposed conductor portion and the insulating coating layer and have found that while removing the end coating using laser light allows for the removal of substantially only the end coating without removing the conductor, there are limitations in improving the adhesion between the exposed conductor portion and the insulating coating layer. If the adhesion between the exposed conductor portion and the insulating coating layer is insufficient, current may flow between wires, between wires and surrounding components, potentially causing motor damage.

[0005] The present invention aims to provide an insulated wire having an end where substantially only the end coating has been removed, exposing the conductor, and when the ends are welded together and an insulating coating layer is then provided around the exposed conductor, the adhesion between the exposed conductor and the insulating coating layer can be sufficiently improved, as well as a method for manufacturing this insulated wire. Furthermore, the present invention aims to provide electrical and electronic equipment using this insulated wire, and a method for manufacturing this electrical and electronic equipment. Furthermore, the phrase "substantially only the end coating is removed" means that the ratio of the conductor cross-sectional area (S2) at the end to the conductor cross-sectional area (S1) at the part of the conductor other than the end where the conductor is exposed (S2 / S1) is 0.95 or greater.

[0006] In view of the above problems, the inventors of this invention conducted extensive research. As a result, they found that when substantially removing only the end coating of an insulated wire by laser irradiation, thereby exposing the conductor at the end of the insulated wire, the conductor surface beneath the end coating can also be unevenly and finely scraped by the laser irradiation, and that this allows the conductor surface at the end to be controlled to a specific arithmetic mean height. Furthermore, they found that by controlling the arithmetic mean height of the conductor surface at the end, when an insulating coating layer is formed around the exposed conductor after welding the ends of the exposed conductors, the adhesion between the exposed conductor and the insulating coating layer is effectively enhanced. This invention was completed after further research based on these findings. [Means for solving the problem]

[0007] The present inventor's above-mentioned problems are solved by the following means. [1] An insulated wire having a conductor and an insulating coating covering the conductor, The insulated wire has an end with an exposed conductor, The ratio (S2 / S1) of the conductor cross-sectional area (S2) at the exposed end of the conductor to the conductor cross-sectional area (S1) at the other end of the conductor is 0.95 or greater. An insulated wire having an arithmetic mean height Sa of the conductor surface at the exposed end of the aforementioned conductor being 1.0 to 5.0 μm. [2] The insulated wire according to [1], wherein the aspect ratio Str of the surface shape of the conductor surface is 0.0 to 0.5. [3] The insulated wire according to [1] or [2], wherein the end of the conductor that is exposed is formed by removing the coating of the end of the insulated wire by laser irradiation. [4] The insulated wire according to any one of [1] to [3], wherein the insulated wire is segmented into a size of 150 to 700 mm in length. [5] The insulated wire according to any one of [1] to [4], wherein the insulated wire is a segmented coil. [6] An electric or electronic device using the insulated wire according to any one of [1] to [5]. [7] The electric or electronic device according to [6], wherein the electric or electronic device is a transformer. [8] An end processing step of irradiating a laser beam onto an end portion of an insulated wire having a conductor and an insulating film covering the periphery of the conductor to remove the insulating film at the end portion and making the arithmetic mean height Sa of the surface of the exposed conductor 1.0 to 5.0 μm, and a method for manufacturing an insulated wire including the same. [9] The method for manufacturing an insulated wire according to [8], wherein in the end processing step, the aspect ratio Str of the surface shape of the exposed conductor is 0.0 to 0.5.

[10] An end processing step of irradiating a laser beam onto an end portion of a segmented insulated wire to remove the insulating film at the end portion and making the arithmetic mean height Sa of the surface of the exposed conductor 1.0 to 5.0 μm, An incorporation step of processing the segmented insulated wire that has undergone the end processing step into a coil shape to form a segmented coil and incorporating the same into a slot of a stator core, A welding step of welding and electrically connecting the conductors at the ends of the segmented coil after the incorporation step, An insulation coating step of providing an insulation coating layer around the exposed conductor portion by insulatingly coating the exposed conductor portion after the welding step and a method for manufacturing an electric or electronic device including the same.

[11] The method for manufacturing an electric or electronic device according to

[10] , wherein in the end processing step, the aspect ratio Str of the surface shape of the exposed conductor is 0.0 to 0.5.

[0008] In the present invention and this specification, a numerical range represented by "~" means a range including the numerical values described before and after "~" as a lower limit value and an upper limit value. For example, when described as "A~B", the numerical range is "A or more and B or less".

Advantages of the Invention

[0009] The insulated wire of the present invention has an end portion where substantially only the end film is removed and the conductor is exposed, and the end portions are welded to each other. Then, when an insulating coating layer is provided around the conductor exposed portion, the adhesion between the exposed conductor portion and the insulating coating layer is sufficiently enhanced. Therefore, an electric / electronic device using the insulated wire of the present invention can maintain its performance for a long period in the usage environment. Further, according to the manufacturing method of the insulated wire of the present invention, the insulated wire of the present invention can be obtained. Further, according to the manufacturing method of the electric / electronic device of the present invention, the electric / electronic device of the present invention can be obtained.

Brief Description of the Drawings

[0010] [Figure 1] It is a cross-sectional view schematically showing a configuration example of an insulated wire according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view taken along line a-a of FIG. 1. [Figure 3] It is a cross-sectional view schematically showing a configuration example of an insulated wire according to another embodiment of the present invention. [Figure 4] It is a schematic perspective view showing a preferred form of a stator used in the electric / electronic device of the present invention. [Figure 5] It is a schematic perspective view showing a preferred form of a stator used in the electric / electronic device of the present invention. [Figure 6] It is an explanatory view schematically showing one form of the manufacturing method of the electric / electronic device of the present invention.

Modes for Carrying Out the Invention

[0011] [Insulated Wire] The insulated wire of the present invention is an insulated wire having a conductor and an insulating film covering the conductor, wherein the insulated wire has an end where the conductor is exposed, the ratio of the conductor cross-sectional area (S2) of the conductor end where the conductor is exposed (S2 / S1) to the conductor cross-sectional area (S1) of the conductors other than the exposed end where the conductor is exposed (S2 / S1) is 0.95 or more, and the arithmetic mean height Sa of the conductor surface of the exposed end where the conductor is exposed is 1.0 to 5.0 μm.

[0012] Preferred embodiments of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the embodiments shown below, except as specified herein. Furthermore, the description with reference to the drawings below is not limited to the forms shown in the drawings, but applies as a description of the structure or inventive features of the present invention.

[0013] Figure 1 is a schematic cross-sectional view showing an example of the configuration of an insulated wire 1 according to one embodiment of the present invention, and Figure 2 is a cross-sectional view of line aa in Figure 1. The insulated wire 1 is an insulated wire that has been segmented (shortened) to a predetermined size. The longitudinal length L1 of the insulated wire 1 can be, for example, 150 to 700 mm. The X, Y, and Z axes shown in Figure 1 are three mutually orthogonal axes and are common to all figures in this specification. The X axis is an axis parallel to the longitudinal direction of the insulated wire 1, and the Y axis is an axis parallel to the short direction of the insulated wire 1. The Z axis is an axis parallel to the thickness direction (short direction perpendicular to the Y axis) of the insulated wire 1.

[0014] As shown in Figure 1, the insulated wire 1 has a rectangular conductor 10, an insulating coating A, and an end 11. The insulating coating A is in contact with the conductor 10 and covers the periphery of the conductor 10. The insulating coating A may be a single-layer structure or a multi-layer structure. The insulated wire 1 of this embodiment will be described below, starting with the conductor 10.

[0015] The conductor 10 can be a wide range of conductors commonly used in insulated wires, and is usually a metal conductor. The metal conductor preferably contains copper or aluminum, and copper wire or aluminum wire is preferably used. If the conductor 10 is a copper wire, its material is, for example, low-oxygen copper, tough pitch copper, or oxygen-free copper. If the conductor 10 is an aluminum wire, its material is, for example, A1070. In order to suppress partial discharge from the corners, the rectangular conductor 10 is preferably provided with R-chamfers (radius of curvature r) at all four corners, as shown in Figure 2. 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) 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 aspect ratio value (D2 / D1) of the width (D2) to the thickness (D1) of the conductor 10 is preferably 2 to 5.

[0016] The insulating film A may be an enamel layer formed by applying a resin varnish containing an insulating resin (insulating polymer) to the conductor 10 and baking it, or an extruded coating layer formed by extruding a thermoplastic resin, or a layer formed by a combination of these. When the insulating film A includes an enamel layer, a thermosetting resin or a thermoplastic resin can be used to form this enamel layer, and an enamel layer formed by curing a thermosetting resin is preferred. Examples of resins used to form the enamel layer include thermosetting resins having imide bonds such as polyimide (PI), polyamideimide (PAI), polyetherimide (PEI), and polyesterimide (PEsI), polyurethane (PU), thermosetting polyester (PEst), H-type polyester (HPE), polyimide hydantoin-modified polyester, polyhydantoin, polybenzimidazole, melamine resin, epoxy resin, etc., and one or more of these can be used.

[0017] When insulating film A includes an extruded coating layer, a wide range of thermoplastic resins commonly used as insulating resin layers for insulated wires can be used as the thermoplastic resin forming material for the extruded coating layer. 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 can be used, as well as polysulfone (PSF), polyethersulfone (PES), polyphenylene sulfide (PPS), polyarylate (U polymer), polyether ketone (PEK), polyaryl ether ketone (PAEK), tetrafluoroethylene-ethylene copolymer (ETFE), polyether ether ketone (PEEK) (modified polyether ether ketone (modified Examples of super engineering plastics include polyether ether ketone (PEEK), tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), thermoplastic polyimide resin (TPI), polyamide-imide (PAI), and liquid crystal polyester. Furthermore, polymer alloys containing the aforementioned engineering plastics include polymer alloys based on polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), ABS / polycarbonate, nylon 6,6, aromatic polyamide resin (aromatic PA), polyphenylene ether / nylon 6,6, polyphenylene ether / polystyrene, and polybutylene terephthalate / polycarbonate. These resins may be used individually or mixed together. Preferably, the thermoplastic resin contains at least one of polyether ether ketone (PEEK), polyphenylene sulfide (PPS), polyethylene terephthalate (PET), and nylon 6,6 (nylon 66, PA66).

[0018] The thickness of insulating film A is preferably 200 μm or less, more preferably 180 μm or less. Furthermore, the thickness of insulating film A is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more. The preferred range for the thickness of insulating film A is 10 to 200 μm, more preferably 20 to 200 μm, and even more preferably 30 to 180 μm.

[0019] The end portion 11 is a conductor 10 that protrudes from the insulating film A in the longitudinal direction of the insulated wire 1, and is formed by removing the insulating film A and exposing the conductor 10. The longitudinal dimension L2 of the end portion 11 is preferably 1 to 50 mm, more preferably 1 to 20 mm, and even more preferably 1 to 15 mm.

[0020] The ratio (S2 / S1) of the conductor cross-sectional area (S2) of the exposed end 11 of the conductor 10 to the conductor cross-sectional area (S1) of the portion 12 covered with the insulating film A of the conductor 10 is 0.95 or greater (Nominal 1), preferably 0.96 to 1.00, more preferably 0.97 to 1.00, and even more preferably 0.98 to 1.00. It is also preferable that S2 / S1 be 0.99 or less. Note that the above "conductor cross-sectional area" is the cross-sectional area along a plane perpendicular to the longitudinal direction of the insulated wire 1 and parallel to the short direction. That is, it is the cross-sectional area of ​​the conductor 10 when viewed in the longitudinal direction of the insulated wire 1.

[0021] The surface of the end portion 11 (the circumferential surface of the end portion 11 around the X-axis) has the insulating film A removed and is further processed to a predetermined surface roughness. The arithmetic mean height Sa of the surface is 1.0 to 5.0 (Nominal 2), preferably 1.2 to 4.5, and more preferably 1.3 to 4.4. The arithmetic mean height Sa is a value measured in accordance with JIS B 0601 (2001). The method for measuring the arithmetic mean height Sa is described in detail in the [Examples] section below. Furthermore, the aspect ratio Str of the surface shape of the end portion 11 is preferably 0.0 to 0.5, more preferably 0.1 to 0.5, and even more preferably 0.2 to 0.4. By having the aspect ratio Str of the surface shape within the range of 0.0 to 0.5, the formation of voids (gaps) in the welded joint after the end portions 11 are welded together can be further suppressed. Therefore, the electrical and mechanical reliability of the welded joint can be maintained over a longer period of time. The surface aspect ratio Str is a value measured in accordance with ISO 25178 surface shape (surface roughness measurement). The surface aspect ratio Str is calculated from five non-overlapping locations on the surface of the edge 11 (area of ​​each location is 1 mm²). 2 ) is the average of five values ​​obtained by measuring each of them at a magnification of 400x using a laser microscope. The method for measuring the aspect ratio Str of the surface shape will be described in detail in the [Examples] section below.

[0022] The means for forming the end portion 11 on the insulated wire 1 is not particularly limited as long as the above provisions 1 and 2 are satisfied, and typically a method of removing the insulating coating A by laser irradiation is employed. Laser irradiation will be described later.

[0023] Figure 3 is a schematic cross-sectional view showing an example of the configuration of an insulated wire 2 according to another embodiment of the present invention. The insulated wire 2 has a conductor 20 with a circular cross-section and an insulating film A that is in contact with the conductor 20 and covers the outer surface of the conductor 20. The diameter of the conductor 20 is preferably 0.3 to 3.0 mm, and more preferably 0.4 to 2.7 mm. The conductor 20 is the same as the conductor 10 described in the embodiments of Figures 1 and 2, except that its cross-sectional shape is circular, and the preferred embodiment is also the same. The insulating coating A of the insulated wire 2 is the same as the insulating coating A described in the embodiments of Figures 1 and 2, except that it covers the conductor 20 with a circular cross-sectional shape, and the preferred embodiment is also the same.

[0024] [Manufacturing method for insulated electric wires] The present invention's method for manufacturing an insulated wire preferably includes an end processing step in which a laser beam is irradiated onto the end of an insulated wire having a conductor and an insulating coating covering the conductor, thereby removing the insulating coating at the end and setting the arithmetic mean height Sa of the exposed conductor surface to 1.0 to 5.0 μm.

[0025] In the aforementioned end processing step, the insulating coating at the end of the insulated wire is removed by laser irradiation to expose the conductor, and the arithmetic mean height Sa of the exposed conductor surface is controlled to 1.0 to 5.0 μm by this laser irradiation or by other means. Other methods include sandblasting and press working, but from the viewpoint of manufacturing efficiency, it is preferable to use the same laser irradiation used to remove the insulating coating to control the arithmetic mean height Sa of the conductor surface. Furthermore, it is preferable to control the aspect ratio Str of the surface shape of the exposed conductor surface to 0.0 to 0.5. The method for controlling the aspect ratio Str of the surface shape can be by laser irradiation or by other methods described above. In particular, it is preferable to use laser irradiation directly to control the aspect ratio Str of the surface shape. For example, by scanning and irradiating with laser light in a certain direction, a desired anisotropy can be imparted to the surface shape of the exposed end conductor, and as a result, the aspect ratio Str of the surface shape can be controlled to a desired range. These specific methods are described in the [Examples] section below. The method of using laser irradiation to remove insulating coatings is itself widely known in the field of insulated wire technology. Furthermore, the arithmetic mean height Sa of the conductor surface and the aspect ratio Str of the surface shape can be controlled by, for example, controlling the irradiation conditions of the laser (e.g., laser frequency, wavelength, and output), or by controlling the irradiation angle and scanning conditions.

[0026] The insulated wire subjected to the end processing step described above can have a length of, for example, 150 to 700 mm. In other words, it is preferable to use a segmented (shortened) insulated wire. By using a segmented insulated wire, an insulated wire suitable for forming a segment coil can be obtained. In the method for manufacturing an insulated wire of the present invention, if the insulated wire, which has a conductor and an insulating coating covering the conductor, is not segmented, it is preferable to segment (shorten) the insulated wire as described above before the end processing step. This makes it possible to obtain an insulated wire of a suitable length for use as a segment coil.

[0027] [Applications of insulated wires] The insulated wire of the present invention can preferably be processed into a segment coil and used in various electrical and electronic equipment, and other fields requiring high voltage resistance and heat resistance. That is, the insulated wire of the present invention may be in the form of a segment coil. The electrical and electronic equipment using this coil is not particularly limited. One preferred embodiment of such electrical and electronic equipment is a transformer. Another example is a rotating electric machine equipped with a stator 30 as shown in Figure 4 (for example, a drive motor for a hybrid or electric vehicle). This rotating electric machine can have the same configuration as a normal rotating electric machine, except that it is equipped with a stator 30. The stator 30 can have the same configuration as a normal stator, except that it uses a segment coil 1, which is one embodiment of the insulated wire of the present invention. That is, the stator 30 has a stator core 31 and a coil 33 in which the segment coil 1 is assembled into a slot 32 of the stator core 31, as shown in Figure 5, and the ends 11 are electrically connected. Here, the segment coil 1 may be assembled into the slot 32 as a single unit, but preferably it is assembled as a pair of two, as shown in Figure 5. In this stator 30, the coil 33, which is formed by connecting the two ends 11 of the bent segment coil 1 as described above in an alternating manner, is housed in the slot 32 of the stator core 31. At this time, the ends 11 of the segment coil 1 may be connected before being housed in the slot 32, or the ends 11 of the segment coil 1 may be bent and connected after being housed in the slot 32.

[0028] [Manufacturing methods for electrical and electronic equipment] The method for manufacturing electrical and electronic equipment of the present invention preferably includes the following steps.

[0029] End processing step: By irradiating the ends of segmented insulated wires with laser light, the insulating coating at the ends is removed, and the arithmetic mean height Sa of the exposed conductor surface is set to 1.0 to 5.0 μm. The segmented insulated wires that have undergone the end processing step are processed into a coil shape to form a segment coil, and then assembled into the slots of the stator core in the assembly process. After the assembly process, a welding process is performed to electrically connect the conductors at the ends of the segment coils by welding them together, and An insulating coating step, which follows the welding step, is performed to provide an insulating coating layer around the exposed conductor portion by insulating coating the exposed conductor portion.

[0030] The length of the segmented insulated wire can be, for example, 150 to 700 mm, as explained above. The end processing step described above is the same as the end processing step described in the method for manufacturing an insulated electric wire of the present invention. The aforementioned assembly process and insulation coating process are known processes, and conventional methods can be applied as appropriate.

[0031] Preferred embodiments of methods for manufacturing electrical and electronic equipment will be described in more detail with reference to the drawings. Figure 6 is a schematic diagram illustrating one embodiment of the manufacturing method for electrical and electronic equipment of the present invention, using the manufacturing of a rotating electric machine as an example. The manufacturing method for electrical and electronic equipment of the present invention is not limited to the following embodiments, except as specified in the present invention.

[0032] Figure 6 shows the process starting from the segmentation process, where a long wound insulated wire is shortened. The insulated wire of a predetermined length obtained in the shortening process is subjected to the end processing process, and then the rotating electric machine is manufactured through the assembly process, the welding process, and the insulating coating process. Each of these processes will be described below.

[0033] <Shortening process> In the shortening process, the insulated wire wrapped around the roller R is cut at predetermined intervals. This results in an insulated wire shortened to the desired length as described above.

[0034] <Edge processing process> In the end processing step, the insulating coating at the end of the shortened insulated wire is removed by burning (thermal decomposition) using laser irradiation, exposing the conductor 10 at that end. Simultaneously, the surface of the exposed conductor 10 is processed by this laser irradiation to a state that satisfies the above specifications 1 and 2 (if necessary, a state in which the aspect ratio Str of the surface shape of the end 11 satisfies 0.0 to 0.5). In this way, an insulated wire 1 is obtained.

[0035] The scanning trajectory of the laser beam irradiation can be, for example, long and parallel, or it may be five-pointed, but it is preferably long and parallel. "Long and parallel scanning trajectory" means that multiple grooves extending in the longitudinal direction of the insulated wire 1 are formed on the surface of the end 11 in the short direction at a predetermined pitch width. "Five-pointed scanning trajectory" means that multiple grooves extending in the longitudinal direction of the insulated wire 1 are formed on the surface of the end 11 in the short direction at a predetermined pitch width, and furthermore, multiple grooves extending in the short direction of the insulated wire 1 are formed in the longitudinal direction at a predetermined pitch width. The above pitch width is preferably 20 to 30 μm.

[0036] Examples of lasers used for laser irradiation include fiber lasers, CO2 lasers, and YAG lasers, and the irradiation may be continuous wave (CW) or pulsed. Methods for removing insulating films by laser irradiation are disclosed, for example, in Japanese Patent Publication No. 6-38330, Japanese Patent Publication No. 2001-309521, and Japanese Patent Publication No. 2005-285755. Examples of specific irradiation conditions for laser light irradiation according to the present invention are described in the [Examples] section below.

[0037] <Assembly Process> In the assembly process, an insulated wire 1, from which the insulating coating at the end has been removed, is bent into a hairpin shape to create a segment coil 1. Next, the segment coil 1 is inserted into a slot 32 of the stator core 31, and the segment coil 1 protruding from the surface of the stator core 31 is twisted.

[0038] <Welding Process> In the welding process, the end 11 of one segment coil 1 and the end 11 of the other segment coil 1 are welded together to create an electrical connection. Examples of welding methods include arc welding, laser welding, electron beam welding, and resistance welding. This welding process is performed to substantially maintain the surface condition (arithmetic mean height Sa and aspect ratio Str of the surface shape) formed in the end processing process for the conductive portion that forms the surface to be insulated.

[0039] <Insulation coating process> After the welding process described above, the exposed conductor portion is coated with, for example, an insulating powder coating, and the exposed conductor portion is coated with an insulating material to form an insulating coating layer 34. In this embodiment, by satisfying the above requirements 1 and 2, the adhesion between the exposed conductor portion and the insulating coating layer 34 is sufficiently enhanced.

[0040] Through the above steps, the desired electrical and electronic equipment can be obtained. [Examples]

[0041] The present invention will be described in more detail based on examples, but the present invention is not limited to the following examples.

[0042] [Manufacturing of insulated wires] <Example 1> In Example 1, an insulated wire 1 (before end processing, the same applies hereafter) as shown in Figures 1 and 2 was manufactured. Conductor 10 is a copper wire (material: oxygen-free copper, cross-sectional shape: rectangular, cross-sectional area: 3 mm 2 (Aspect ratio: 5) was used. To form the insulating film A, a die similar in shape to the insulating film A formed on the conductor 10 was used. A thermosetting resin varnish (manufactured by Unitika, product name: U-imide, resin type: polyimide) was coated onto the conductor 10 using the die, and the conductor was passed through a hot air circulating furnace with a length of 8m and a furnace temperature of 400-650°C at a speed that resulted in a passage time of 10-90 seconds. This process was repeated 16-35 times to form an insulating film A (enamel layer) with a thickness of 50 μm.

[0043] <Example 2> In Example 2, the insulated wire 2 shown in Figure 3 was fabricated. The conductor 20 consists of copper wire (material: oxygen-free copper, cross-sectional shape: circular, cross-sectional area: 3 mm²). 2 ) was used. For the formation of insulating film A, a 30mm full-flight extruder screw with an L / D ratio of 25 and a compression ratio of 3 was used. Using thermoplastic resin (Victrex Japan Co., Ltd., product name: 450G, resin type: PEEK), the extrusion coating was performed at 390°C (extrusion die temperature) using an extrusion die so that the cross-sectional shape of insulating film A would be similar to the shape of the conductor 20, thereby forming insulating film A (extruded coating layer) with a thickness of 50 μm.

[0044] <Example 3> In Example 3, the insulated wire 1 shown in Figures 1 and 2 was fabricated. The conductor 10 consists of copper wire (material: oxygen-free copper, cross-sectional shape: flat rectangular, cross-sectional area: 6 mm²). 2 Aspect ratio: 2) was used. In forming insulating film A, an insulating film A (enamel layer) with a thickness of 100 μm was formed in the same manner as in Example 1.

[0045] <Example 4> In Example 4, the insulated wire 1 shown in Figures 1 and 2 was fabricated. The conductor 10 consists of copper wire (material: oxygen-free copper, cross-sectional shape: flat rectangular, cross-sectional area: 6 mm²). 2 (Aspect ratio: 5) was used. In forming the insulating film A, an insulating film A (extruded coating layer) with a thickness of 100 μm was formed in the same manner as in Example 2.

[0046] <Example 5> In Example 5, the insulated wire 1 shown in Figures 1 and 2 was fabricated. The conductor 10 consists of copper wire (material: oxygen-free copper, cross-sectional shape: flat rectangular, cross-sectional area: 9 mm²). 2 (Aspect ratio: 5) was used. In forming insulating film A, an insulating film A (enamel layer) with a thickness of 170 μm was formed in the same manner as in Example 1.

[0047] <Example 6> In Example 6, the insulated wire 2 shown in Figure 3 was fabricated. The conductor 20 is made of copper wire (material: oxygen-free copper, cross-sectional shape: circular, cross-sectional area: 9 mm²). 2) was used. In the formation of the insulating film A, an insulating film A (enamel layer) with a thickness of 170 μm was formed in the same manner as in Example 1.

[0048] <Example 7> In Example 7, the insulated wire 1 shown in FIGS. 1 and 2 was produced. For the conductor 10, a copper wire (material: tough pitch copper, cross-sectional shape: rectangular, cross-sectional area: 3 mm 2 , aspect ratio: 5) was used. In the formation of the insulating film A, an insulating film A (enamel layer) with a thickness of 50 μm was formed in the same manner as in Example 1.

[0049] <Example 8> In Example 8, the insulated wire 1 shown in FIGS. 1 and 2 was produced. For the conductor 10, a copper wire (material: tough pitch copper, cross-sectional shape: rectangular, cross-sectional area: 6 mm 2 , aspect ratio: 2) was used. In the formation of the insulating film A, an insulating film A (enamel layer) with a thickness of 100 μm was formed in the same manner as in Example 1.

[0050] <Example 9> In Example 9, the insulated wire 1 shown in FIGS. 1 and 2 was produced. For the conductor 20, a copper wire (material: tough pitch copper, cross-sectional shape: rectangular, cross-sectional area: 6 mm 2 , aspect ratio: 5) was used. In the formation of the insulating film A, an enamel layer with a thickness of 50 μm was formed in the same manner as in Example 1, and then, in the same manner as in Example 2, an extrusion coating layer with a thickness of 120 μm was formed outside the enamel layer. In Example 9, the thickness of the insulating film A was 170 μm.

[0051] <Example 10> In Example 10, the insulated wire 1 shown in FIGS. 1 and 2 was produced. For the conductor 10, an aluminum wire (material: A1070, cross-sectional shape: rectangular, cross-sectional area: 3 mm 2 , aspect ratio: 5) was used. In forming insulating film A, an insulating film A (extruded coating layer) with a thickness of 50 μm was formed in the same manner as in Example 2.

[0052] <Example 11> In Example 11, the insulated wire 1 shown in Figures 1 and 2 was fabricated. The conductor 10 is made of aluminum wire (material: A1070, cross-sectional shape: flat rectangular, cross-sectional area: 6 mm²). 2 Aspect ratio: 2) was used. In forming the insulating film A, an insulating film A (extruded coating layer) with a thickness of 100 μm was formed in the same manner as in Example 2.

[0053] <Comparative Example 1> In Comparative Example 1, the insulated wire 1 shown in Figures 1 and 2 was fabricated. The conductor 10 consists of copper wire (material: oxygen-free copper, cross-sectional shape: flat rectangular, cross-sectional area: 6 mm²). 2 Aspect ratio: 2) was used. In forming insulating film A, an insulating film A (enamel layer) with a thickness of 100 μm was formed in the same manner as in Example 1.

[0054] <Comparative Example 2> In Comparative Example 2, the insulated wire 2 shown in Figure 3 was fabricated. The conductor 20 consists of copper wire (material: tough pitch copper, cross-sectional shape: circular, cross-sectional area: 6 mm²). 2 ) was used. In forming the insulating film A, an insulating film A (extruded coating layer) with a thickness of 100 μm was formed in the same manner as in Example 2.

[0055] <Comparative Example 3> In Comparative Example 3, the insulated wire 1 shown in Figures 1 and 2 was fabricated. The conductor 10 consists of copper wire (material: oxygen-free copper, cross-sectional shape: flat rectangular, cross-sectional area: 6 mm²). 2 Aspect ratio: 2) was used. In forming insulating film A, an insulating film A (enamel layer) with a thickness of 100 μm was formed in the same manner as in Example 1.

[0056] <Comparative Example 4> In Comparative Example 4, the insulated wire 1 shown in Figures 1 and 2 was fabricated. The conductor 10 consists of copper wire (material: oxygen-free copper, cross-sectional shape: flat rectangular, cross-sectional area: 6 mm²). 2 (Aspect ratio: 5) was used. In forming the insulating film A, an insulating film A (extruded coating layer) with a thickness of 100 μm was formed in the same manner as in Example 2.

[0057] [Laser peel test (edge ​​processing)] The insulated wires in the examples and comparative examples were segmented into 500 mm long segments. The insulating coating covering one end of each segment was removed by laser irradiation, while the exposed conductor surface was finely abraded by the same laser irradiation to control surface roughness. The laser irradiation conditions were as shown in [Table 1] below. CW stands for Constant Wave. In each example and comparative example, the ratio (S2 / S1) of the conductor cross-sectional area of ​​the exposed end (S2) to the conductor cross-sectional area of ​​the other end (S1) was within the range of 0.95 to 1.00.

[0058] [Table 1]

[0059] [Surface roughness measurement] Next, the arithmetic mean height Sa and the aspect ratio Str of the surface shape were measured in the segments of the insulated wires according to the examples and comparative examples in which the laser peeling test was performed. Specifically, the arithmetic mean height Sa and the aspect ratio Str of the surface shape were measured in five different regions (area of ​​each region = 1 mm²) of the conductor surface exposed by laser irradiation. 2For each of the above, the average of five values ​​obtained by measuring at 400x magnification using a laser microscope (Keyence Corporation, product name: VK-X250) was used. If impregnating varnish or other materials were attached to the wire, the surface roughness was measured after dissolving and removing them with chemicals such as an insulating coating stripper (Meiwa Chemical Industry Co., Ltd., product name: Solcoat). In the case of powder coating, the powder coating was mechanically peeled off and removed because it is a brittle material. The measurement results for the arithmetic mean height Sa are shown in Table 2, and the measurement results for the aspect ratio Str of the surface shape are shown in Table 3.

[0060] [Shear strength test] Two segments of insulated wires were prepared according to the examples and comparative examples in which the laser peeling test described above was performed. The two segments were placed in parallel, with the exposed conductor ends facing each other (simulating welding as shown in Figure 6), and the exposed conductor ends were welded together using a fiber laser. Next, the exposed conductor portions were immersed at high temperature in a powder bath containing a mixed powder of epoxy resin and filler to apply an insulating powder coating and form an insulating coating layer. The shear strength of the insulating coating layer corresponding to the laser beam scanning surface in the laser peeling test described above (adhesion force between the portion where the insulating coating was peeled off for welding and the insulating coating layer, N / mm²) 2 The material was measured using a sample cut to a diameter of 1 mm, and evaluated according to the following criteria. The results are shown in Table 2. (Criteria for evaluating shear strength tests) ◎: Shear strength is 1.0 N / mm 2 That's all. ○: Shear strength is 0.7 N / mm 2 More than 1.0N / mm 2 less than △: Shear strength is 0.5 N / mm 2 Above 0.7 N / mm 2 less than ×: Shear strength is 0.5 N / mm 2 less than

[0061] [Table 2]

[0062] As shown in Table 2, the insulated wires in Comparative Examples 1 to 4 exhibited poor paint adhesion (adhesion between the portion where the insulating coating was removed for welding and the insulating coating layer). In contrast, the insulated wires in Examples 1 to 11 were found to have excellent paint adhesion.

[0063] [Void Area Ratio Measurement] For welded joints with an insulating coating layer formed by the powder coating described above, the void area ratio (%) in the observation field was determined by wet polishing the cross section along the short direction of the electric wire (cross section along the direction perpendicular to the long direction of the electric wire) and then observing the cross section. Specifically, the wet-polished cross section of the welded joint was photographed at 50x magnification using an optical microscope, and the obtained image was binarized using image processing software (ImageJ). Then, the ratio of the void area (E2) to the conductor area (E1) in the image ((E2 / E1) × 100) was calculated. In the same manner, the ratio of E2 to E1 was calculated for a total of three welded joint cross sections. The average of the calculated values ​​for the three cross sections (three calculated values) was taken as the void area ratio (%). The results are shown in Table 3. TIFF0007862290000003.tif182152

[0064] As shown in Table 3, in the insulated wires of Comparative Examples 1 and 2, where the aspect ratio Str of the surface shape is in the range of 0.0 to 0.5, the formation of voids in the weld area was suppressed. However, in the insulated wires of Comparative Examples 3 and 4, where the aspect ratio Str of the surface shape is greater than 0.5, a larger amount of voids were formed in the weld area than in Comparative Examples 1 and 2. Similarly, in the insulated wires according to Examples 1 to 11, where the aspect ratio Str of the surface shape is in the range of 0.0 to 0.5, it was confirmed that the formation of voids in the welded area was significantly suppressed compared to the insulated wires according to Comparative Examples 3 and 4. From these results, it was found that when the aspect ratio Str of the surface shape is within the range of 0.0 to 0.5, the formation of voids in the weld area is effectively suppressed. [Explanation of Symbols]

[0065] 1,2...Insulated wire, 10,20...Conductor, 11...End, 34...Insulating coating layer, A...Insulating film.

Claims

1. An insulated wire having a conductor and an insulating coating covering the conductor, The insulated wire has an end with an exposed conductor, The ratio (S2 / S1) of the conductor cross-sectional area (S2) at the exposed end of the conductor to the conductor cross-sectional area (S1) at the other end of the conductor is 0.95 or greater. The arithmetic mean height Sa of the conductor surface at the exposed end of the aforementioned conductor is 1.0 to 5.0 μm, and the aspect ratio Str of the surface shape of the aforementioned conductor surface is 0.0 to 0.

5. An insulated wire for use as a component of electrical and electronic equipment, comprising welding the exposed ends of the conductors together and then providing an insulating coating layer around the exposed conductor portion.

2. The insulated wire according to claim 1, wherein the insulated wire is an insulated wire segmented into lengths of 150 to 700 mm.

3. The insulated wire according to claim 2, wherein the insulated wire is a segment coil.

4. Electrical and electronic equipment using an insulated wire as described in any one of claims 1 to 3.

5. The electrical and electronic equipment according to claim 4, wherein the electrical and electronic equipment is a transformer.

6. A method for manufacturing an insulated wire, comprising an end processing step in which a laser beam is irradiated onto the end of an insulated wire having a conductor and an insulating coating covering the conductor, thereby removing the insulating coating at the end and making the arithmetic mean height Sa of the surface of the exposed conductor 1.0 to 5.0 μm and the aspect ratio Str of the surface shape 0.0 to 0.5, A method for manufacturing an insulated wire, wherein the insulated wire obtained by the above manufacturing method is used as a component of electrical and electronic equipment by welding together the ends where the conductors are exposed by the end processing step, and then providing an insulating coating layer around the exposed conductor portion.

7. An end processing step is performed by irradiating the ends of segmented insulated wires with laser light to remove the insulating coating at the ends, and to set the arithmetic mean height Sa of the exposed conductor surface to 1.0 to 5.0 μm and the aspect ratio Str of the surface shape to 0.0 to 0.

5. The segmented insulated wires, having undergone the aforementioned end processing step, are processed into a coil shape to form a segment coil, and then assembled into the slots of the stator core in an assembly step. After the assembly process, a welding process is performed in which the conductors at the ends of the segment coils are welded together to electrically connect them. After the welding process, an insulating coating process is performed to provide an insulating coating layer around the exposed conductor portion by insulating coating the exposed conductor portion. A method for manufacturing electrical and electronic equipment, including [specific details omitted].

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