Stranded conductor and method for manufacturing the same

Abstract

To provide a lightly compressed stranded-wire conductor which can pass a plating test and can suppress an increase in conductor resistance, and to provide a method of producing the same.SOLUTION: A stranded-wire conductor 1 is composed of a plurality of lightly compressed metal element wires 2 each having plating on its surface. The metal element wires 2 has a plating thickness of 1.0 μm or less and is stranded in a multilayer structure of three or more layers. When the metal element wires 2 arranged in an outermost layer 3 are defined as outermost layer wires 21, the metal element wires 2 arranged in an inner layer 4 inside the outermost layer 3 by one layer are defined as inner layer wires 22, and the metal element wires 2 arranged inside the inner layer 4 are defined as center wires 23 in the multilayer structure, a plating test of JIS C3002 8(2) term is performed on the outermost layer wires 21, the inner layer wires 22, and the center wires 23, with a test result that the colors of the test liquids obtained in the plating test are all lighter than the color of the standard liquid in the plating test, and the color of the test liquid of the inner layer wires 22 is lighter than the color of the test liquid of the outermost layer wires 21.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a stranded conductor and a method for manufacturing the same.

Background Art

[0002] As an electric wire for railway vehicles and the like, a wire obtained by coating an insulator around a lightly compressed stranded conductor is used. The lightly compressed stranded conductor is formed, for example, by inserting a stranded conductor obtained by twisting a plurality of metal strands into a metal die having an opening hole at the center to lightly compress the outer surface of the stranded conductor.

[0003] Note that Patent Document 1 exists as prior art document information related to the invention of this application.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, as the metal strands used for the lightly compressed stranded conductor, plated wires having plating on the surface are used. And in the lightly compressed stranded conductor, in the state after light compression, it is required to pass a plating test and the conductor resistance is within the range of the standard value.

[0006] However, with lightly compressed stranded conductors, especially when the compression ratio is high (for example, ≥10%), friction between the metal strands can damage the plating, sometimes causing them to fail the plating test. To pass the plating test, one might consider increasing the thickness of the plating on the metal strands (for example, thicker than 1.0 μm), but in this case, depending on the size of the conductor and the type of plating, the conductor resistance may increase, potentially causing the conductor resistance to fall outside the standard value (= upper limit), or failing to achieve sufficient likelihood relative to the standard value.

[0007] Therefore, the present invention aims to provide a lightly compressed stranded conductor that can pass plating tests and suppress an increase in conductor resistance, as well as a method for manufacturing the same. [Means for solving the problem]

[0008] The present invention aims to solve the above problems and provides a stranded conductor in which a plurality of metal strands having a plating on their surface are lightly compressed, wherein the thickness of the plating on the plurality of metal strands is 1.0 μm or less and the strands are twisted together in a multilayer structure of three or more layers. The outer diameter of the aforementioned metal wire is 0.18 mm or more and 0.26 mm or less, and the compression ratio is 10% or more. In the multilayer structure described above, when the metal wires arranged in the outermost layer are designated as the outermost layer line, the metal wires arranged in the inner layer one layer inside the outermost layer are designated as the inner layer line, and the metal wires arranged inside the inner layer are designated as the center line, a plating test according to JISC3002 8(2) is performed on the outermost layer line, the inner layer line, and the center line, and the color of the test solution obtained in the plating test is lighter than the color of the standard solution in the plating test, and the color of the test solution for the inner layer line is lighter than the color of the test solution for the outermost layer line. Ku , The conductor resistance is 98% or less of the standard value (15.5 Ω / km) based on JRISJ1001. A stranded wire conductor is provided.

[0009] Furthermore, the present invention aims to solve the above problems and comprises a twisting step of twisting together a plurality of metal wires having a plating on their surface, and a light compression step of lightly compressing the twisted metal wires to form a stranded conductor, wherein the plurality of metal wires have a plating thickness of 1.0 μm or less and are twisted together in a multilayer structure of three or more layers. The outer diameter of the metal wire is 0.18 mm or more and 0.26 mm or less, and the compression ratio in the light compression process is 10% or more. In the multilayer structure described above, when the metal wires arranged in the outermost layer are called the outermost layer wires, the metal wires arranged in the inner layer one layer inside the outermost layer are called the inner layer wires, and the metal wires arranged inside the inner layer are called the center wire, the tension applied to the outermost layer wires and the inner layer wires in the twisting process is equal. Ku , The tension is determined within a range of 0.69 N (70 gf) to 1.47 N (150 gf) depending on the outer diameter of the metal wire, and the conductor resistance of the resulting stranded conductor is 98% or less of the standard value (15.5 Ω / km) based on JRISJ1001. The present invention provides a method for manufacturing stranded wire conductors. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a lightly compressed stranded conductor that can pass plating tests and suppress an increase in conductor resistance, as well as a method for manufacturing the same. [Brief explanation of the drawing]

[0011] [Figure 1] (a) is a cross-sectional view showing a cross-section perpendicular to the longitudinal direction of a stranded conductor according to one embodiment of the present invention, and (b) is a photograph showing the results of a plating test. [Figure 2] This is a flowchart of a method for manufacturing a stranded conductor according to one embodiment of the present invention. [Figure 3] (a) and (b) are photographs showing the results of a plating test of a comparative example that is comparable to the present invention. [Modes for carrying out the invention]

[0012] [Embodiment] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0013] (Stranded conductor 1) Figure 1(a) is a cross-sectional view showing a cross-section perpendicular to the longitudinal direction of the stranded conductor 1 according to this embodiment, and (b) is a photograph showing the results of the plating test.

[0014] As shown in Figure 1(a), the stranded conductor 1 is a lightly compressed stranded conductor made by twisting together multiple metal strands 2 that have been plated on their surfaces. The stranded conductor 1 is constructed by twisting together multiple metal strands 2 so that, in a cross section perpendicular to its longitudinal direction, it has a multilayer structure of three or more layers from the center outwards.

[0015] In this embodiment, metal strands 2 with an outer diameter of 0.18 mm in a plated state are used, and 50 metal strands 2 are twisted together so that 3, 9, 16, and 22 metal strands 2 are stacked in a cross section perpendicular to the longitudinal direction of the stranded conductor 1, from the center outwards, to form a four-layer stranded conductor 1. Hereinafter, the 22 metal strands 2 arranged in the outermost layer 3 of the stranded conductor 1 will be referred to as the outermost layer wires 21, the 16 metal strands 2 arranged in the inner layer 4 one layer inward (towards the center) from the outermost layer 3 will be referred to as the inner layer wires 22, and the 3 and 9 (total of 12) metal strands 2 arranged in the central layer 5, which is inward (towards the center) from the inner layer 4 will be referred to as the central wires 23. The central layer 5 includes all layers inside the inner layer 4 and may include multiple layers (22 layers in the example in Figure 1).

[0016] The number of metal strands 2 used in the stranded conductor 1 is not limited to the illustrated example. For example, a four-layer structure may be constructed by stacking 1, 6, 12, and 18 metal strands 2 in a cross section perpendicular to the longitudinal direction of the stranded conductor 1, from the center outwards. The number of layers of the stranded conductor 1 is also not limited to the illustrated example. A three-layer structure or a structure with five or more layers may be constructed. The outer diameter of the metal strands 2 is preferably between 0.15 mm and 0.30 mm (for example, 0.18 mm, 0.23 mm, or 0.26 mm). The outer diameter of the metal strands 2 is the outer diameter with the surface plated, and can be determined, for example, by a structural test method in accordance with JISC3002.

[0017] The metal wire 2 has plating on the surface of a core material made of copper or a copper alloy. In this embodiment, tin plating is used as the plating. The thickness of the plating of the metal wire 2 is set to 1.0 μm or less. The thickness of the plating of the metal wire 2 is more preferably 0.5 μm or more and 1.0 μm or less. In this embodiment, the thickness of the plating of the metal wire 2 is about 0.8 μm on average. Thereby, it is possible to suppress the conductor resistance of the stranded conductor 1 from increasing due to the influence of the plating, and it becomes possible to make the conductor resistance within the range of the standard value with sufficient likelihood. The standard value referred to here is, for example, the value of the conductor resistance defined by a standard such as JRIS J1001. The standard value of the stranded conductor 1 formed by stranding 50 metal wires 2 having an outer diameter of 0.18 mm with plating on the surface is 15.5 Ω / km. In this embodiment, when it is 98% (15.2 Ω / km) or less of the above standard value (15.5 Ω / km), it is determined that it is within the range of the standard value with likelihood.

[0018] (Results of plating test) Figure 1(b) is a photograph showing the results of a plating test performed using the ammonium persulfate method specified in JISC3002 section 8(2) on metal strands 2 arranged in each layer of a stranded conductor 1 that has been lightly compressed to a compressibility of 10% or more (12.5%), namely the outermost layer wire 21, the inner layer wire 22, and the center wire 23. In this plating test, a metal strand 2 with a length of 1667 mm is used as a test piece. After sealing both ends of the test piece so that the copper is not exposed, it is immersed in a specified test solution for a predetermined time and the change in color is observed. Then, the color of the test solution after the predetermined time has elapsed is visually compared to whether it is darker than the standard solution (colorimetric standard solution). The darker the color of the test solution, the greater the amount of copper on the surface of the test piece (higher concentration), and the greater the damage to the plating. Therefore, if the color of the test solution is lighter than the color of the standard solution, the plating test is passed, and if the color of the test solution is darker than the color of the standard solution, the plating test is failed. In the plating test shown in Figure 1(b), metal wires 2 with a plating thickness of 1.0 μm or less (average value of approximately 0.8 μm) were used. Figure 1(b) also shows the results of the plating test performed on each of the two test pieces taken from the stranded conductor 1 described above, with the upper row showing the results for the first test piece and the lower row showing the results for the second test piece.

[0019] As shown in Figure 1(b), in the stranded conductor 1 according to this embodiment, when a plating test was performed on the outermost layer wire 21, the inner layer wire 22, and the center wire 23, the color of the test solution obtained in the plating test was lighter than the color of the standard solution in all cases, indicating that the plating test was passed. Furthermore, the color of the test solution for the inner layer wire 22 was lighter than the color of the test solution for the outermost layer wire 21. Moreover, the color of the test solution became darker in the order of center wire 23, inner layer wire 22, and outermost layer wire 21.

[0020] From these results, it can be seen that the closer the stranded conductor 1 is to the conductor center, the less the plating damage. As can also be seen from Fig. 1(a), the closer to the conductor center, the smaller the degree of deformation of the metal strands 2 due to light compression, and it can be seen that the strands are in a state closer to a circular shape. That is, the closer to the conductor center, the smaller the influence of friction between the metal strands 2 due to light compression, the smaller the plating damage, and the smaller the copper concentration measured on the surface of the metal strands 2. In other words, in the stranded conductor 1 according to the present embodiment, the copper concentration measured on the surface of the metal strands 2 constituting the inner layer wire 22 is smaller than the copper concentration measured on the surface of the metal strands 2 constituting the outermost layer wire 21, and the copper concentration measured on the surface of the metal strands 2 constituting the center wire 23 is smaller than the copper concentration measured on the surface of the metal strands 2 constituting the inner layer wire 22. Thereby, in the stranded conductor 1 according to the present embodiment, even when lightly compressed at a compression rate of 10% or more, it can pass the plating test and suppress an increase in conductor resistance.

[0021] In the present embodiment, such a distribution of the degree of plating damage is realized by adjusting the tension applied to the metal strands 2 when twisting the metal strands 2. Details of this point will be described below.

[0022] (Manufacturing method of the stranded conductor 1) As shown in Fig. 2, when manufacturing the stranded conductor 1, first, a twisting process (step S1) of twisting a plurality of metal strands 2 plated on the surface is performed. At this time, the metal strands 2 are twisted while applying an appropriate tension. Then, a light compression process (step S2) is performed by passing the twisted metal strands 2 through a metal die having an inner diameter smaller than the standard outer diameter of the twisted metal strands 2 to perform light compression. Thereby, the stranded conductor 1 of Fig. 1 is obtained. The compression rate in the light compression process is, for example, 10% or more.

[0023] (Consideration for suppressing plating damage) During light compression, the stranded metal wires 2 rub against each other and against the die as they are passed through a narrow die, causing damage to the plating. The inventors conducted plating tests and found that in conventional stranded conductors, the inner layer wires 22 suffered the most significant damage to the plating.

[0024] Conventionally, in the twisting process, it was common practice to set the tension so that it gradually increased from the inner layer to the outer layer in the radial direction in order to stabilize the shape of the twisted conductor 1. However, with this method, the tension applied to the outermost layer wire 21 was too high, and it is thought that the inner layer wires 22 rubbed against the outermost layer wire 21, damaging the plating of the inner layer wires 22.

[0025] As an example, Comparative Example 1 was created using a structure similar to that of stranded conductor 1 shown in Figure 1(a), with tensions applied to the center wire 23 of the first layer at 80gf, the center wire 23 of the second layer at 100gf, the inner layer wire 22 at 120gf, and the outermost layer wire 21 at 140gf. The results of the plating test on the center wire 23, inner layer wire 22, and outermost layer wire 21 of Comparative Example 1 are shown in Figure 3(a). Figure 3(a) shows the results of the plating test performed on each of the three test pieces, with the top row showing the results for the first test piece, the middle row showing the results for the second test piece, and the bottom row showing the results for the third test piece. As shown in Figure 3(a), in Comparative Example 1, the color of the test solution for the inner layer wire 22 was the darkest, and was darker than the standard solution, so the plating test failed. In other words, in Comparative Example 1, the copper concentration measured on the surface of the metal wire 2 constituting the inner layer wire 22 is greater than the copper concentration measured on the surface of the metal wire 2 constituting the outermost layer wire 21.

[0026] Therefore, in this embodiment, the tension applied to the outermost layer wire 21 and the inner layer wire 22 during the twisting process was made equal. This suppresses friction between the inner layer wire 22 and the outermost layer wire 21, and significantly reduces damage to the plating on the inner layer wire 22. More specifically, the copper concentration measured on the surface of the inner layer wire 22 can be reduced to less than 20 mass%. The copper concentration on the surface of the inner layer wire 22 can be obtained by measuring the surface of the inner layer wire 22 using energy dispersive X-ray spectroscopy (EDX analysis).

[0027] To suppress friction between the metal strands 2, it is desirable to minimize the tension applied to the metal strands 2. In this embodiment, the tension applied to all metal strands 2, including the center wire 23, inner layer wires 22, and outermost layer wires 21, was made equal during the twisting process. In this specification, "equal tension" includes not only cases where the tension is perfectly equal, but also cases where there is an error that can be considered substantially equivalent (for example, an error of about ±10%).

[0028] Furthermore, if the tension applied to the metal strands 2 is too low, the metal strands 2 will wobble when fed from the feeding device, causing the outer shape of the stranded conductor 1 to become unstable, and conversely, the plating will be damaged more severely. Therefore, it is necessary to apply an appropriate tension that does not cause wobbling during feeding.

[0029] Here, we examine the specific values ​​of the tension applied to the metal strands 2 during the twisting process. In this embodiment, when forming a stranded conductor 1 with the structure shown in Figure 1(a) using 50 metal strands 2 with an outer diameter of 0.18 mm, the tension applied to the metal strands 2 was varied from 50 gf to 100 gf in 10 gf increments to create the stranded conductor 1, and a plating test was performed in the same manner as in Figure 1(b). As a result, the plating test failed when the tension was 60 gf or less, and when it was 100 gf or more. This is thought to be because the shape of the stranded conductor 1 became unstable when the tension was 60 gf or less, and because the friction between the metal strands 2 increased when the tension was 100 gf or more. Therefore, when forming a stranded conductor 1 with the structure shown in Figure 1(a) using 50 metal strands 2 with an outer diameter of 0.18 mm, the tension applied to the metal strands 2 should be between 70 gf (0.69 N) and 90 gf (0.88 N).

[0030] Furthermore, when 37 metal wires 2 with an outer diameter of 0.26 mm were used and arranged in four layers of 1, 6, 12, and 18 wires, it was found that the plating test was passed when the tension applied to the metal wires 2 was 150 gf (1.47 N). From these results, it can be concluded that when the outer diameter of the metal wires 2 is between 0.18 mm and 0.26 mm, it is possible to pass the plating test by adjusting the tension applied to the metal wires 2 within the range of 70 gf (0.69 N) to 150 gf (1.47 N) while suppressing damage to the plating.

[0031] From these results, when the outer diameter of the metal wire 2 is 0.18 mm or more and 0.26 mm or less, the tension applied to the outermost layer wire 21 and the inner layer wire 22 in the stranding process should be determined to be equal within the range of 0.69 N (70 gf) or more and 1.47 N (150 f) or less, depending on the outer diameter of the metal wire 2 that make up the outermost layer wire 21 and the inner layer wire 22. The tension applied to the metal wire 2 can be measured in the stranding process using a tension meter installed in a stranding machine or the like used to twist multiple metal wires 2 together.

[0032] The case where the plating thickness exceeds 1.0 μm was also investigated. A stranded conductor of Comparative Example 2 was created with the same structure as stranded conductor 1 shown in Figure 1(a), but with a plating thickness of approximately 1.2 μm (average value), and a plating test was performed. The tension applied to the metal wires 2 in each layer was kept constant at 80 gf. The results of the plating test are shown in Figure 3(b). Figure 3(b) shows the results of the plating test performed on each of the three test pieces, with the top row showing the results for the first test piece, the middle row showing the results for the second test piece, and the bottom row showing the results for the third test piece. As shown in Figure 3(b), the results of the plating test showed that the center wire 23, inner layer wires 22, and outermost layer wires 21 were all thinner than the standard solution and passed. However, the conductor resistance of the stranded conductor of Comparative Example 2 was high, exceeding 99.3% of the upper limit of the standard, 15.5 Ω / km, and a sufficient likelihood was not obtained for the standard value.

[0033] (Operation and Effects of the Embodiment) As described above, in the stranded conductor 1 according to this embodiment, the metal strands 2 have a plating thickness of 1.0 μm or less and are twisted together in a multilayer structure of three or more layers. The outermost layer wire 21, the inner layer wire 22, and the center wire 23 are subjected to a plating test according to JISC3002 8(2), and the color of the test solution obtained in the plating test is lighter than the color of the standard solution in the plating test, and the color of the test solution for the inner layer wire 22 is lighter than the color of the test solution for the outermost layer wire 21.

[0034] As a result, even when the plating thickness of the metal wire 2 is reduced to 1.0 μm or less and the compression ratio is 10% or more, damage to the plating can be suppressed and the plating test can be passed. Consequently, it becomes possible to pass the plating test while suppressing an increase in conductor resistance.

[0035] (Summary of the embodiments) Next, the technical concept understood from the embodiments described above will be described using the reference numerals and other symbols from the embodiments. However, the reference numerals and other symbols in the following description are not limited to the components in the claims that are specifically shown in the embodiments.

[0036] [1] A stranded conductor (1) in which a plurality of metal strands (2) having a plating on their surface are lightly compressed, wherein the thickness of the plating on the plurality of metal strands (2) is 1.0 μm or less, and the strands are twisted together in a multilayer structure of three or more layers, and in the multilayer structure, when the metal strands (2) arranged in the outermost layer (3) are called the outermost layer wires (21), the metal strands (2) arranged in the inner layer (4) one layer inside the outermost layer (3) are called the inner layer wires (22), and the metal strands (2) arranged inside the inner layer (4) are called the center wires (23), the outermost layer wires (21), the inner layer wires (22), and the center wires (23) are governed by JISC3002 A stranded conductor (1) is subjected to the plating test described in item 8(2), wherein the color of the test solution obtained in the plating test is lighter than the color of the standard solution in the plating test, and the color of the test solution for the inner layer wire (22) is lighter than the color of the test solution for the outermost layer wire (21).

[0037] [2] The stranded conductor (1) according to [1], wherein the color of the test solution becomes progressively darker along the center line (23), the inner layer line (22), and the outermost layer line (21).

[0038] [3] The stranded conductor (1) according to [1], wherein the copper concentration measured on the surface of the inner layer wire (22) is less than 20 mass%.

[0039] [4] The stranded conductor (1) according to [1], wherein the copper concentration measured on the surface of the metal strand (2) constituting the inner layer wire (22) is less than the copper concentration measured on the surface of the metal strand (2) constituting the outermost layer wire (21), and the copper concentration measured on the surface of the metal strand (2) constituting the center wire (23) is less than the copper concentration measured on the surface of the metal strand (2) constituting the inner layer wire (22).

[0040] [5] A method for manufacturing a stranded conductor, comprising: a twisting step of twisting together a plurality of metal strands (2) having a plating on their surface; and a light compression step of lightly compressing the twisted metal strands (2) to form a stranded conductor (1), wherein the plurality of metal strands (2) have a plating thickness of 1.0 μm or less and are twisted together in a multilayer structure of three or more layers, and in the multilayer structure, when the metal strands (2) arranged in the outermost layer (3) are called the outermost layer wires (21), the metal strands (2) arranged in an inner layer (4) one layer inside the outermost layer (3) are called the inner layer wires (22), and the metal strands (2) arranged inside the inner layer (4) are called the center wire (23), the tension applied to the outermost layer wires (21) and the inner layer wires (22) in the twisting step is equal.

[0041] [6] The method for manufacturing a stranded conductor according to [5], wherein the tension applied to the outermost layer wire (21), the inner layer wire (22), and the center wire (23) in the twisting step is equal.

[0042] [7] The method for manufacturing a stranded conductor according to [5], wherein the outer diameter of the metal strand (2) is 0.18 mm or more and 0.26 mm or less, and the tension is determined in the range of 0.69 N (70 gf) or more and 1.47 N (150 f) or less depending on the outer diameter of the metal strand.

[0043] Although embodiments of the present invention have been described above, the embodiments described above do not limit the invention as defined in the claims. Furthermore, it should be noted that not all combinations of features described in the embodiments are necessarily essential for solving the problem of the invention. In addition, the present invention can be implemented with appropriate modifications without departing from its spirit. [Explanation of Symbols]

[0044] 1… Stranded conductor 2… Metal wire 21…Outermost layer line 22…Inner layer lines 23…Center line 3…Outermost layer 4…Inner layer 5…Central layer

Claims

1. A stranded conductor in which multiple metal strands having a plated surface are lightly compressed, The aforementioned plurality of metal wires have a plating thickness of 1.0 μm or less and are twisted together in a multilayer structure of three or more layers. The outer diameter of the aforementioned metal wire is 0.18 mm or more and 0.26 mm or less. The compression ratio is 10% or more. In the aforementioned multilayer structure, when the metal wire arranged in the outermost layer is defined as the outermost layer line, the metal wire arranged in an inner layer one layer inside the outermost layer is defined as the inner layer line, and the metal wire arranged inside the inner layer is defined as the center line, A plating test according to JIS C3002 Section 8(2) is performed on the outermost layer line, the inner layer line, and the center line, and the color of the test solution obtained in the plating test is lighter than the color of the standard solution in the plating test, and the color of the test solution for the inner layer line is lighter than the color of the test solution for the outermost layer line. The conductor resistance is 98% or less of the standard value (15.5 Ω / km) based on JRIS J1001. Stranded wire conductor.

2. The color of the test solution becomes progressively darker along the center line, the inner layer line, and the outermost layer line. The stranded conductor according to claim 1.

3. The copper concentration measured on the surface of the inner layer line is less than 20 mass%, The stranded conductor according to claim 1.

4. The copper concentration measured on the surface of the metal wire constituting the inner layer is smaller than the copper concentration measured on the surface of the metal wire constituting the outermost layer. The concentration of copper measured on the surface of the metal wire constituting the center line is smaller than the concentration of copper measured on the surface of the metal wire constituting the inner layer line. The stranded conductor according to claim 1.

5. A twisting process in which multiple metal wires having a plated surface are twisted together, The process includes a light compression step of lightly compressing the twisted metal strands to form a stranded conductor, The aforementioned plurality of metal wires have a plating thickness of 1.0 μm or less and are twisted together in a multilayer structure of three or more layers. The outer diameter of the aforementioned metal wire is 0.18 mm or more and 0.26 mm or less. The compression ratio in the aforementioned light compression process is 10% or more. In the aforementioned multilayer structure, when the metal wire arranged in the outermost layer is defined as the outermost layer line, the metal wire arranged in an inner layer one layer inside the outermost layer is defined as the inner layer line, and the metal wire arranged inside the inner layer is defined as the center line, In the aforementioned twisting process, the tension applied to the outermost layer wire and the inner layer wire are equal. The tension is determined in a range of 0.69 N (70 gf) or more and 1.47 N (150 gf) or less, depending on the outer diameter of the metal wire. The conductor resistance of the formed stranded conductor is 98% or less of the standard value (15.5 Ω / km) based on JRIS J1001. A method for manufacturing stranded conductors.

6. In the twisting process, the tension applied to the outermost layer wire, the inner layer wire, and the center wire is equal. The method for manufacturing a stranded conductor according to claim 5.

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