Apparatus and method for manufacturing enameled copper wire

Abstract

To provide an apparatus and a method for manufacturing an enameled copper wire capable of suppressing the occurrence of an appearance abnormal part.SOLUTION: An apparatus for manufacturing an enameled copper wire includes a paint application unit configured to apply a paint to a surface of a traveling conductor, and a baking unit configured to bake the conductor to which the paint is applied. The apparatus for manufacturing enameled copper wires may further include a dehumidifier configured to adjust an absolute humidity of a space in which the apparatus is installed to be equal to or lower than 18g / m3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an apparatus for manufacturing an enameled copper wire and a method for manufacturing an enameled copper wire. [Background technology]

[0002] An enameled copper wire comprises a conductor and an enamel coating. The conductor is mainly made of copper. The enamel coating covers the surface of the conductor. Patent Document 1 describes a method for manufacturing an enameled copper wire. In this method, an enamel paint is applied to the surface of the conductor to form a coating. The enamel coating is then formed by baking. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-3913 Summary of the Invention [Problem to be solved by the invention]

[0004] In some cases, the produced enameled copper wire may have a visual defect. In one aspect of the present disclosure, it is preferable to provide an apparatus for producing an enameled copper wire and a method for producing an enameled copper wire that can suppress the occurrence of the visual defect. [Means for solving the problem]

[0005] One aspect of the present disclosure is an apparatus for manufacturing an enameled copper wire, the apparatus comprising: a paint application unit configured to apply paint to a surface of a running conductor; and a baking unit configured to bake the conductor to which the paint has been applied, the apparatus being configured to maintain an absolute humidity of 18 g / m in a space in which the apparatus is installed. 3 The enameled copper wire manufacturing apparatus further includes a dehumidifying unit configured as follows: The enameled copper wire manufacturing apparatus according to one aspect of the present disclosure can suppress the occurrence of visual defects in the manufactured enameled copper wire.

[0006] Another aspect of the present disclosure is a method for producing an enameled copper wire, which comprises applying paint to a surface of a running conductor and baking the conductor to which the paint has been applied, and wherein the absolute humidity of the space in which the method for producing the enameled copper wire is carried out is set to 18 g / m 3 The method for producing an enameled copper wire according to another aspect of the present disclosure can suppress the occurrence of visual defects in the produced enameled copper wire. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an explanatory diagram showing the configuration of a manufacturing device for a rectangular enameled copper wire. [Figure 2] FIG. 2 is a cross-sectional view showing the cross-sectional shape of a rectangular copper wire. [Figure 3] FIG. 2 is a cross-sectional view showing the cross-sectional shape of a drawn rectangular copper wire. [Figure 4] 1A and 1B are schematic diagrams illustrating a mechanism by which a visually abnormal portion occurs. [Figure 5] 1 is a graph showing the relationship between the temperature and relative humidity of a space and the likelihood of occurrence of a visual abnormality. [Figure 6] Fig. 6A is an explanatory diagram showing a single visually abnormal portion, and Fig. 6B is an explanatory diagram showing a continuous visually abnormal portion. [Figure 7] 1 is a graph showing the relationship between the absolute humidity of the space and the proportion of products in which the visual abnormality was not suppressed. DETAILED DESCRIPTION OF THE INVENTION

[0008] Exemplary embodiments of the present disclosure will now be described with reference to the drawings. First Embodiment 1. Configuration of the manufacturing device 1 and manufacturing method for rectangular enameled copper wire A method for manufacturing a rectangular enameled copper wire will be described with reference to Figures 1 to 3. The method for manufacturing a rectangular enameled copper wire uses a manufacturing apparatus 1 for rectangular enameled copper wire shown in Figure 1. The manufacturing apparatus 1 for rectangular enameled copper wire includes a dance ring or bobbin 3, a round wire drawing machine 5, a rectangular rolling mill 7, an annealing furnace 9, a rectangular wire drawing machine 11, an annealing furnace 13, a paint applicator 15, a baking furnace 17, a winder 19, and a dehumidifier 20. The dehumidifier 20 corresponds to the dehumidifying section. The paint applicator 15 corresponds to the paint application section. The baking furnace 17 corresponds to the baking section. The manufacturing apparatus 1 for rectangular enameled copper wire is a horizontal type with a production line extending horizontally.

[0009] A linear conductor 23 is wound around the dance wheel or bobbin 3. The conductor 23 is drawn out from the dance wheel or bobbin 3, travels along a route that passes through a round wire drawing machine 5, a flat rolling mill 7, an annealing furnace 9, a flat wire drawing machine 11, an annealing furnace 13, a coating machine 15, and a baking furnace 17 in this order, and is then wound onto a winder 19. However, the processed conductor 23, i.e., a flat copper drawn wire material 23B (described later), passes through the section that includes the coating machine 15 and the baking furnace 17 multiple times.

[0010] The conductor 23 is made of copper or a copper alloy. The cross-sectional shape of the conductor 23 is circular until it is subjected to flat-rolling, which will be described later. The cross-section of the conductor 23 is a cross section perpendicular to the longitudinal direction of the conductor 23.

[0011] The round wire drawing machine 5 draws the conductor 23, which has a circular cross-sectional shape. The flat rolling machine 7 performs flat rolling on the traveling conductor 23. The conductor 23 that has undergone flat rolling is called a flat copper wire 23A. As shown in FIG. 2, the cross-sectional shape of the flat copper wire 23A is a shape consisting of two parallel sides 24A, 24B and two arc-shaped end faces 26A, 26B. In the cross-section, the sides 24A, 24B are straight. In the cross-section, the length of the sides 24A, 24B is greater than the length of the end faces 26A, 26B. The annealing furnace 9 anneals the flat copper wire 23A.

[0012] The flat wire drawing machine 11 performs flat wire drawing on the running flat copper wire 23A. Flat wire drawing is a process of continuously cold drawing the flat copper wire 23A using a flat wire drawing die. The conductor 23 that has undergone flat wire drawing is referred to as a flat copper wire material 23B.

[0013] The cross-sectional shape of the drawn rectangular copper wire material 23B is a rounded rectangle, as shown in Fig. 3. The long sides of the rounded rectangle are sides 24A and 24B. The short sides 22A and 22B of the rounded rectangle are sides that originate from end faces 26A and 26B of the rectangular copper wire 23A.

[0014] As shown in FIG. 1, the direction in which the conductor 23 travels in the rectangular wire drawing machine 11 is referred to as the traveling direction TR. The opposite direction to the traveling direction TR is referred to as the upstream direction US. The annealing furnace 13 anneals the rectangular copper wire drawn material 23B. The paint applicator 15 applies enamel paint to the surface of the rectangular copper wire drawn material 23B to form an enamel paint film of a predetermined thickness on the surface of the rectangular copper wire drawn material 23B. The wire speed of the rectangular copper wire drawn material 23B when the paint applicator 15 applies the enamel paint is preferably 14 m / min or more, and more preferably 20 m / min or more.

[0015] In the baking furnace 17, a coating of enamel paint of a predetermined thickness is applied to the traveling drawn rectangular copper wire material 23B, on which a coating of enamel paint of a predetermined thickness has been formed by the coating applicator 15, and the baking furnace 17 applies heat to bake the wire material to form an enamel coating. As shown in FIG. 1, the application of enamel paint by the coating applicator 15 and the formation of the enamel coating by the baking furnace 17 are repeated. For example, the coating and baking are repeated 40 times. As a result, a rectangular enameled copper wire 25 having a predetermined coating thickness is produced. The rectangular enameled copper wire 25 is wound onto the winder 19.

[0016] The method for forming the enamel coating is, for example, as follows: An enamel paint is applied to the surface of the rectangular copper drawn wire material 23B. The enamel paint is, for example, a paint containing a resin and a solvent. Next, the solvent in the enamel paint applied to the surface of the rectangular copper drawn wire material 23B is evaporated, and the resin in the enamel paint is hardened. After the solvent has evaporated and the resin has hardened, a rectangular enameled copper wire 25 is formed. The rectangular enameled copper wire 25 corresponds to an enameled copper wire.

[0017] The dehumidifier 20 dehumidifies the space 31 in which the manufacturing apparatus 1 is installed, thereby reducing the absolute humidity in the space 31. The space 31 is a space in which the rectangular enameled copper wire 25 is manufactured. The dehumidifier 20 reduces the absolute humidity in the space 31 to 18 g / m 3 For example, a control unit (not shown) or an operator determines that the absolute humidity in the space 31 is 18 g / m or less based on the measured value of the absolute humidity in the space 31. 3 The dehumidifier 20 is controlled as follows: The higher the absolute humidity in the space 31, the stronger the dehumidifying capacity of the dehumidifier 20 is.

[0018] 2. Effects of the manufacturing device 1 and manufacturing method for rectangular enameled copper wire The manufacturing apparatus 1 and manufacturing method for rectangular enameled copper wire can suppress the occurrence of visually abnormal portions 51 in the rectangular enameled copper wire 25. The reason for this is presumably as follows. S1 in FIG. 4 shows a state in which an enamel coating 33 is formed on a rectangular drawn copper wire material 23B, and a coating film 35 is formed on top of that. The enamel coating 33 is a film formed by applying and baking an enamel paint. The coating film 35 is a film formed by applying an enamel paint. The coating film 35 contains a large amount of solvent and is an uncured film. While the enamel paint remains in the tank of the paint applicator 15, the enamel paint absorbs moisture from its surface. When the absolute humidity becomes high, areas 37 with high moisture content are locally formed in the coating film 35.

[0019] S2 is the state in which the coating film 35 is heated after the state in S1. When the absolute humidity in the space is high, a high-viscosity layer 39 forms on the surface of the coating film 35. The high-viscosity layer 39 is the part where the coating film 35 absorbs moisture from the space 31 and becomes more viscous. The moisture and solvent contained in the high-moisture part 37 cannot volatilize due to the presence of the high-viscosity layer 39. As a result, bubbles form in the high-moisture part 37, and an appearance abnormality 51 occurs. S3 is the state in which the coating film 35 with the appearance abnormality 51 formed after the state in S2 becomes an enamel coating 33, and an enamel coating 33 is further layered on top of that.

[0020] The manufacturing apparatus 1 and manufacturing method for rectangular enameled copper wire are configured to set the absolute humidity of the space 31 at 18 g / m 3 % or less, it is difficult for the high-viscosity layer 39 to occur. Therefore, the moisture contained in the moisture-rich portion 37 is easily evaporated, and foaming is difficult to occur. As a result, the appearance abnormality portion 51 is difficult to occur.

[0021] Example 1 The rectangular enameled copper wire 25 was manufactured using the manufacturing apparatus 1 while varying the temperature and relative humidity of the space 31. All manufacturing conditions except the temperature and relative humidity of the space 31 were kept constant. Visual defects 51 were detected in the manufactured rectangular enameled copper wire 25. The relationship between the temperature and relative humidity of the space 31 and the likelihood of the visual defects 51 occurring is shown in Figure 5.

[0022] The horizontal axis of FIG. 5 is temperature. The vertical axis of FIG. 5 is relative humidity. On the boundary line L shown in FIG. 5, the absolute humidity of the space 31 is 18 g / m 3 The area X shown in FIG. 5 is the area where the absolute humidity of the space 31 is 18 g / m 3 The area Y shown in FIG. 5 is an area where the absolute humidity of the space 31 is 18 g / m 3 In region X, the appearance defect 51 was unlikely to occur in the rectangular enameled copper wire 25. In region Y, the appearance defect 51 was likely to occur in the rectangular enameled copper wire 25. From these results, it can be seen that the absolute humidity of the space 31 is 18 g / m 3 It has been confirmed that if the temperature is below this, the appearance defect 51 is unlikely to occur in the rectangular enameled copper wire 25.

[0023] <Example 2> 1. Manufacturing of rectangular enamelled copper wire 25 The rectangular enameled copper wire 25 was produced using the production apparatus 1 while varying the absolute humidity of the space 31. The production conditions were kept constant except for the absolute humidity of the space 31. The production conditions were as follows:

[0024] The cross-sectional size of the drawn rectangular copper wire 23B is: the length of sides 24A and 24B is 3 mm. The length of sides 22A and 22B is 2 mm. Enamel paint composition: This paint is composed of an imide polymer and a solvent. Examples of imide polymers include polyimide, polyamic acid, polyamideimide, and polyesterimide. Examples of solvents include, but are not limited to, N-methyl-2-pyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide. Furthermore, other solvents and additives may be mixed. The wire speed of the rectangular copper wire 23B when the paint applicator 15 applies the enamel paint: 20 m / min Amount of enamel paint applied per application: 4μm Baking temperature in baking furnace 17: 700 to 750°C Number of times enamel paint is applied: 40 times Total thickness of enamel coating: 160 μm

[0025] 2: Evaluation of rectangular enameled copper wire 25 The number of visually abnormal portions 51 was counted in the manufactured rectangular enameled copper wire 25. The method for counting the number of visually abnormal portions 51 was as follows. First, the surface of the rectangular enameled copper wire 25 was photographed with a camera. If one visually abnormal portion 51 is present in the camera image and is sufficiently separated from other visually abnormal portions 51, as shown in FIG. 6A, it is determined that one visually abnormal portion 51 is present. For example, if only one visually abnormal portion 51 is present within the field of view of the camera image, it is determined that one visually abnormal portion 51 is present.

[0026] As shown in Figure 6B, if multiple visually abnormal portions 51 are lined up along one direction D and both of the following conditions J1 and J2 are satisfied, the multiple visually abnormal portions 51 are determined to be one continuous abnormal portion 53.

[0027] (J1) The width W is 0.5 mm or more. (J2) The aspect ratio A is 4 or more. The width W is the overall width of the plurality of visually abnormal portions 51 in a direction perpendicular to the direction D. The aspect ratio A is the value obtained by dividing the length P by the width W. The length P is the overall length of the plurality of visually abnormal portions 51 in the direction D.

[0028] When one continuous abnormal portion 53 exists, it is determined that there are n visually abnormal portions 51 represented by the following formula (1). Equation (1) n=f(P / P0) In formula (1), P / P0 is the value obtained by dividing P by P0. P0 is a fixed value, for example, 32 mm. P0 is, for example, the width of the field of view in an image obtained by photographing the surface of rectangular enameled copper wire 25 with a camera. In formula (1), f(P / P0) is the smallest integer greater than P / P0. For example, if P / P0 is 0.5, f(P / P0) is 1. For example, if P / P0 is 1.5, f(P / P0) is 2.

[0029] The produced rectangular enameled copper wires 25 were classified into products with suppressed visual defects and products without suppressed visual defects based on the number of visual defects 51. Products with suppressed visual defects are rectangular enameled copper wires 25 in which the number of visual defects 51 per 3200 m is less than 30. Products without suppressed visual defects are rectangular enameled copper wires 25 in which the number of visual defects 51 per 3200 m is 30 or more.

[0030] Next, the percentage of products with unsuppressed visual abnormalities was calculated for each absolute humidity value in the space 31. The results are shown in Figure 7. The horizontal axis of Figure 7 is absolute humidity, and the vertical axis is the percentage of products with unsuppressed visual abnormalities. The absolute humidity in the space 31 was measured both at the dance wheel or bobbin 3 and at the paint applicator 15. Figure 7 shows the absolute humidity at both locations.

[0031] As shown in FIG. 7, the absolute humidity of the space 31 is 18 g / m 3 If it is less than 18g / m 3 The proportion of products with unsuppressed visual abnormalities was significantly lower than when the ratio exceeded 100%.

[0032] <Other embodiments> Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be implemented in various modified forms.

[0033] (1) The enameled copper wire manufacturing apparatus 1 may manufacture an enameled copper wire other than a rectangular enameled copper wire, for example, a round enameled copper wire. (2) The function of one component in each of the above embodiments may be shared among multiple components, or the functions of multiple components may be performed by one component. Also, part of the configuration of each of the above embodiments may be omitted. Furthermore, at least part of the configuration of each of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

[0034] (3) In addition to the above-described rectangular enameled copper wire manufacturing apparatus 1, the present disclosure can also be realized in various forms, such as a system including the rectangular enameled copper wire manufacturing apparatus 1, a method for controlling absolute humidity, and the like. [Explanation of symbols]

[0035] 1...flat enameled copper wire manufacturing equipment, 3...dance ring or bobbin, 5...round wire drawing machine, 7...flat rolling mill, 9...annealing furnace, 11...flat wire drawing machine, 13...annealing furnace, 15...paint applicator, 17...baking furnace, 19...winder, 20...dehumidifier, 22A, 22B...short side, 23...conductor, 23A...flat copper wire, 23B...flat copper wire drawing material, 24A, 24B...side, 25...flat enameled copper wire, 26A, 26B...end face, 31...space, 33...enamel coating, 35...coating film, 39...high viscosity layer, 51...visual abnormality, 53...continuous abnormality

Claims

1. a paint application unit configured to apply paint to a surface of a running conductor; a baking unit configured to bake the conductor to which the paint has been applied; An apparatus for manufacturing an enameled copper wire, comprising: The absolute humidity of the space in which the manufacturing apparatus is installed is set to 18 g / m ３ Further comprising a dehumidifying unit configured to: Enamelled copper wire manufacturing equipment.

2. The enameled copper wire manufacturing apparatus according to claim 1, The linear speed of the conductor when the coating material is applied by the coating material application unit is 14 m / min or more. Enamelled copper wire manufacturing equipment.

3. Paint is applied to the surface of the running conductor, The conductor to which the paint has been applied is baked. A method for producing an enameled copper wire, comprising: The absolute humidity of the space in which the enameled copper wire manufacturing method is carried out is 18 g / m ３ To the following, Manufacturing method of enamelled copper wire.

4. A method for producing an enameled copper wire according to claim 3, The linear speed of the conductor when applying the paint is 14 m / min or more. Manufacturing method of enamelled copper wire.

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