Power transmission line, core wire, and method for manufacturing power transmission line

Abstract

To avoid breakage of a core wire.SOLUTION: A power transmission line includes a central part having a core wire, and an outer twisted wire layer disposed by twisting a plurality of outer wires so as to surround an outer periphery of the central part. The core wire includes a plurality of carbon fibers, a matrix resin covering the plurality of carbon fibers, and a plurality of elastic particles which is disposed between the plurality of carbon fibers in the matrix resin and which is more flexible than the matrix resin.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an electric power transmission line, a core wire, and a method for manufacturing an electric power transmission line. [Background technology]

[0002] In recent years, development of so-called low-loss conductors, high-capacity conductors, or low-sag conductors has been underway as overhead transmission conductors (hereinafter also referred to as transmission conductors). As a transmission conductor that meets these requirements, a transmission conductor having a carbon composite in the center (hereinafter also referred to as a composite core conductor) has been considered (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-225835 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to avoid breakage of the core wire. [Means for solving the problem]

[0005] According to one aspect of the present disclosure, A power transmission line, a central portion having a core wire; an outer stranded wire layer provided by stranding a plurality of outer wires so as to surround an outer periphery of the central portion; Equipped with The core wire is A plurality of carbon fibers; A matrix resin covering the plurality of carbon fibers; a plurality of elastic particles dispersed among the plurality of carbon fibers in the matrix resin and being softer than the matrix resin; Equipped A power line is provided. Effect of the Invention

[0006] According to the present disclosure, breakage of the core wire can be avoided. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic cross-sectional view perpendicular to the axial direction of a power transmission line according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a schematic cross-sectional view taken along an axial direction of a core wire according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [Description of the embodiments of the present disclosure] <Inventor's findings> The above-mentioned composite core electric wire includes, for example, a core wire having a plurality of carbon fibers and a matrix resin covering the plurality of carbon fibers at the center.

[0009] Here, in the core wire of the composite core electric wire, multiple carbon fibers are solidified together by a matrix resin. Therefore, the neutral axis of the core wire coincides with the center axis of the core wire. The "neutral axis" here means the axis along which the stress becomes zero when bending stress is applied. When the core wire is bent, tensile stress is applied outside the neutral axis of the core wire, while compressive stress is applied inside the neutral axis of the core wire.

[0010] When such a composite core electric wire is bent to a certain bending radius, for example, the matrix resin may crack outside the neutral axis of the core wire, causing the carbon fibers to scatter. Specifically, when the carbon composite core electric wire is bent and the surface strain of the core wire reaches about 2%, which is the standard elongation value of carbon fibers, the core wire may break. For example, when the diameter of the core wire is 6.0 mm, the bending radius at which the core wire breaks is about 150 mm.

[0011] Therefore, as a result of extensive research, the inventors have found a configuration that makes it possible to avoid breakage in the above-mentioned composite core electric wire.

[0012] The present disclosure is based on the above findings of the inventors.

[0013] <Embodiments of the present disclosure> Next, embodiments of the present disclosure will be listed and described.

[0014] [1] A power transmission line according to one embodiment of the present disclosure, a central portion having a core wire; an outer stranded wire layer provided by stranding a plurality of outer wires so as to surround an outer periphery of the central portion; Equipped with The core wire is A plurality of carbon fibers; A matrix resin covering the plurality of carbon fibers; a plurality of elastic particles dispersed among the plurality of carbon fibers in the matrix resin and being softer than the matrix resin; Equipped with. With this configuration, breakage of the core wire can be avoided.

[0015] [2] In the power transmission line according to [1] above, The core wire is configured such that, when the power transmission line is bent, a neutral axis of the core wire shifts from a central axis of the core wire to a central axis of each of the plurality of carbon fibers. With this configuration, breakage of the core wire can be avoided.

[0016] [3] The power transmission line according to any one of [1] or [2] above, The material constituting the elastic particles has a lower Young's modulus than the matrix resin. According to this configuration, the elastic particles having a relatively low modulus of elasticity allow the core wire to bend.

[0017] [4] In the power transmission line according to any one of [1] to [3] above, The material constituting the plurality of elastic particles in 25 has a modulus of longitudinal elasticity of 1 MPa or more and 100 MPa or less. According to this configuration, by setting the modulus of elasticity of the elastic particles to 1 MPa or more, it is possible to suppress a decrease in the tensile strength of the core wire, while by setting the modulus of elasticity of the elastic particles to 100 MPa or less, it is possible to stably tolerate bending of the core wire.

[0018] [5] In the power transmission line according to any one of [1] to [4] above, The material constituting the elastic particles has a strain energy release rate higher than the strain energy release rate of the matrix resin. According to this configuration, the elastic particles having a relatively high strain energy release rate can allow bending of the core wire.

[0019] [6] In the power transmission line according to any one of [1] to [5] above, The material constituting the plurality of elastic particles has a strain energy release rate of 1500 J / m 2 More than 10000J / m 2 The following is the result. According to this configuration, the strain energy release rate of the elastic particles is set to 1500 J / m 2 By setting the elastic particle strain energy release rate at 10,000 J / m or more, the core wire can be stably tolerated when bent. 2 By setting the above to the above range, it is possible to suppress a decrease in the tensile strength of the core wire.

[0020] [7] The power transmission line according to any one of [1] to [6] above, Each of the plurality of elastic particles includes at least one of a thermosetting elastomer and a thermoplastic elastomer. According to this configuration, the elastic particles can satisfy the above-mentioned longitudinal elastic modulus or strain energy release rate.

[0021] [8] The power transmission line according to any one of [1] to [7] above, The volume average particle size of each of the plurality of elastic particles is not less than 10 μm and not more than 100 μm. According to this configuration, by setting the volume average particle diameter of the elastic particles to 10 μm or more, the flexibility of the elastic particles themselves in the matrix resin can be ensured, while by setting the volume average particle diameter of the elastic particles to 100 μm or less, a plurality of elastic particles can be stably dispersed in the matrix resin.

[0022] [9] The power transmission line according to any one of [1] to [8] above, The content of the elastic particles in the core wire is 5% by mass or more and 25% by mass or less. According to this configuration, by setting the content of the elastic particles to 5% by mass or more, it is possible to stably tolerate bending of the core wire, while by setting the content of the elastic particles to 25% by mass or less, it is possible to suppress deterioration of the mechanical properties of the power transmission cable caused by excess elastic particles.

[0023]

[10] The power transmission line according to any one of [1] to [9] above, The core wire satisfies the following formula (1). 0.8≦B / A≦1.2 (1) Where: When a cross section including the central axis of the core wire is observed, A is a ratio of a total area of ​​the plurality of elastic particles in the inner region to an area of ​​the inner region from the central axis of the core wire to a position of a diameter Φ / 2 in the cross section, B is a ratio of the total area of ​​the elastic particles in the outer region to the area of ​​the outer region located outside the inner region in the cross section, Φ is the overall diameter of the core wire. According to this configuration, since B / A≧0.8, it is possible to ensure bendability in the outer region of the core wire while suppressing excessive deterioration of mechanical properties in the inner region of the core wire, whereas since B / A≦1.2, it is possible to ensure bendability in the inner region of the core wire while suppressing excessive deterioration of mechanical properties in the outer region of the core wire.

[0024]

[11] The power transmission line according to any one of [1] to

[10] above, The central portion further has a coating layer that covers an outer periphery of the core wire and contains a metal. According to this configuration, the core wire can be protected by the covering layer.

[0025]

[12] A core wire according to another aspect of the present disclosure includes: It is used for a power transmission line according to any one of the above [1] to

[11] . With this configuration, breakage of the core wire can be avoided.

[0026]

[13] A method for manufacturing a power transmission line according to another aspect of the present disclosure includes: forming a core; forming an outer stranded layer by stranding a plurality of outer wires around an outer periphery of the central portion; Equipped with The step of forming the central portion includes the step of forming a core wire, The step of forming the core wire includes: Providing a plurality of carbon fibers; forming a matrix resin so as to cover the carbon fibers, and dispersing a plurality of elastic particles, which are softer than the matrix resin, among the carbon fibers in the matrix resin; Equipped with. With this configuration, breakage of the core wire can be avoided.

[0027] [Details of the embodiment of the present disclosure] Next, embodiments of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0028] (1) Power Lines With reference to FIG. 1, a power transmission line (overhead power transmission line) 10 according to an embodiment of the present disclosure will be described.

[0029] The power transmission cable 10 of this embodiment is configured as a so-called aluminum conductor composite core cable, and has, for example, a central portion 100 and an outer stranded wire layer 300.

[0030] In the following, the "axial direction" of the power transmission line 10 refers to the direction of the central axis of the power transmission line 10, and in some cases may be rephrased as the longitudinal direction of the power transmission line 10. The "radial direction" of the power transmission line 10 refers to the direction perpendicular to the axial direction of the power transmission line 10, and in some cases may be rephrased as the transverse direction of the power transmission line 10. The above terms related to the power transmission line 10 can also be used for other linear members (such as the core wire 120).

[0031] (center) The central portion 100 is configured to function as, for example, a tension member that bears the tension of the power transmission line 10 when the power transmission line 10 is strung. The central portion 100 is provided at the center of the power transmission line 10 in the radial direction and extends in the axial direction of the power transmission line 10.

[0032] In this embodiment, the central portion 100 includes, for example, a core wire 120 and a coating layer 140. Here, the central portion 100 includes, for example, one core wire 120.

[0033] The core wire 120 includes, for example, a carbon composite. The linear expansion coefficient of the carbon composite is lower than, for example, the linear expansion coefficient of an aluminum-clad steel wire used as a steel core of an aluminum-clad steel core aluminum stranded wire (ACSR / AC). The specific gravity of the carbon composite is lower than, for example, the specific gravity of an aluminum-clad steel wire. The tensile strength of the carbon composite is higher than, for example, the tensile strength of an aluminum-clad steel wire. This makes it possible to reduce the sag of the power transmission cable 10. Also, by increasing the cross-sectional area of ​​the outer stranded wire layer 300, it is possible to reduce the resistance of the outer stranded wire layer 300.

[0034] The core wire 120 of this embodiment will be described in detail later.

[0035] (external stranded wire layer) The outer stranded wire layer 300 is configured as a conductor portion through which current mainly flows during power transmission. The outer stranded wire layer 300 is provided by twisting together a plurality of outer element wires 320 so as to surround the outer periphery of the core portion 100.

[0036] The outer stranded wire layer 300 is made of, for example, aluminum (Al) or an Al alloy. In this embodiment, the outer stranded wire 320 is, for example, a heat-resistant aluminum alloy wire (TAL in Japan, AT1 in IEC 62004), a super heat-resistant aluminum alloy wire (ZTAL in Japan, AT3 in IEC 62004), or a soft aluminum wire. This allows the power transmission conductor 10 to be used in a high temperature range, and the current capacity of the power transmission conductor 10 can be increased.

[0037] The outer stranded wire layer 300 is, for example, a plurality of layers concentrically stacked around the central axis of the core 100. In the present embodiment, for example, two outer stranded wire layers 300 are provided. Specifically, the power transmission cable 10 has, for example, a first outer stranded wire layer 300a and a second outer stranded wire layer 300b from the core 100 side toward the outside.

[0038] In this embodiment, the cross-sectional shape of each of all the outer stranded wires 320 constituting the outer stranded wire layer 300 is, for example, a sector shape. This allows the cross-sectional area of ​​the outer stranded wire layer 300 to be increased.

[0039] (2) Core wire The core wire 120 of this embodiment will be described with reference to FIG.

[0040] As shown in FIG. 2, the core wire 120 of this embodiment includes, for example, a plurality of carbon fibers 122, a matrix resin 124, and a plurality of elastic particles 126.

[0041] (Carbon Fiber) The carbon fibers 122 are extremely fine fibers made of carbon. The multiple carbon fibers 122 are arranged (oriented) along the axial direction of the carbon fibers 122. The multiple carbon fibers 122 are scattered within the core wire 120. At least some of the carbon fibers 122 are separated from the other carbon fibers 122.

[0042] The carbon fiber 122 is produced, for example, by subjecting a raw material, organic polymer fiber, to flame-proofing treatment in the presence of oxygen and then carbonizing treatment. An example of the raw material for the carbon fiber 122 is polyacrylonitrile (PAN).

[0043] The carbon fiber 122 has the following characteristics, for example: Tensile strength: 3500MPa to 7000MPa Modulus of elasticity: 200GPa or more and 600GPa or less Elongation: 0.7% to 2.2% Density: 1.7g / cm 3 More than 1.95g / cm 3 below Diameter of a single fiber: 1 μm to 10 μm

[0044] (Matrix resin) The matrix resin 124, for example, covers the plurality of carbon fibers 122. That is, the matrix resin 124 is provided, for example, interposed between the plurality of carbon fibers 122, or provided so as to surround the outer periphery of an assembly of the plurality of carbon fibers 122. The plurality of carbon fibers 122 are bundled and solidified by such matrix resin 124.

[0045] The matrix resin 124 includes, for example, a thermosetting resin. Specifically, the matrix resin 124 is a thermosetting epoxy resin or the like.

[0046] (Elastic particles) The elastic particles 126 are, for example, dispersed among the carbon fibers 122 in the matrix resin 124. Each of the elastic particles 126 is configured to be more flexible than the matrix resin, for example.

[0047] In this embodiment, since the core wire 120 includes the above-mentioned multiple elastic particles 126, the core wire 120 is configured such that, for example, when the power transmission cable 10 is bent, the neutral axis of the core wire 120 shifts from the central axis CA of the core wire 120 to each central axis of the multiple carbon fibers 122. This allows the core wire 120 as a whole to bend while maintaining its shape.

[0048] In this embodiment, the Young's modulus of the material constituting the multiple elastic particles 126 is, for example, lower than the Young's modulus of the matrix resin 124. This allows the bending of the core wire 120 to be tolerated by the elastic particles 126 having a relatively low Young's modulus.

[0049] The "modulus of longitudinal elasticity" referred to here is measured, for example, in accordance with JIS K7161-1:2014.

[0050] Here, the longitudinal elastic modulus of the epoxy resin constituting the matrix resin 124 at 25° C. is, for example, not less than 2.6 GPa and not more than 3.0 GPa.

[0051] In contrast, the modulus of longitudinal elasticity of the material constituting the multiple elastic particles 126 at 25° C. may be, for example, 1 MPa or more and 100 MPa or less, or 1 MPa or more and 10 MPa or less. By setting the modulus of longitudinal elasticity of the elastic particles 126 to 1 MPa or more, it is possible to suppress a decrease in the tensile strength of the core wire 120. On the other hand, by setting the modulus of longitudinal elasticity of the elastic particles 126 to 100 MPa or less, or 10 MPa or less, it is possible to stably tolerate bending of the core wire 120.

[0052] In this embodiment, the strain energy release rate of the material constituting the multiple elastic particles 126 is higher than, for example, the strain energy release rate of the matrix resin 124. This allows the bending of the core wire 120 to be tolerated by the elastic particles 126 having a relatively high strain energy release rate.

[0053] The "strain energy release rate" referred to here is measured, for example, in accordance with ASTM D5045.

[0054] Specifically, a flat plate containing the resin to be measured is first prepared, and a notch is formed in the flat plate to prepare a test piece. The test piece is used to perform a compact tension test or a three-point bending test. In the test, the bending load and displacement are measured. In the obtained bending load-load line displacement diagram, a load P that satisfies the requirements described in 9.1.1 of ASTM D5045 is selected. Q The calculated load P Q The provisional fracture toughness value K is calculated according to the procedure in A1.4 or A2.5 of ASTM D5045, depending on the test method. Q Calculate.

[0055] Calculated provisional fracture toughness value K Q When the requirements of 7.1.2 of ASTM D5045 are met, the provisional fracture toughness value K Q "Linear elastic plane strain fracture toughness value K Ic " The obtained K Ic By substituting into the following equation (1), the strain energy release rate G Ic is required.

[0056]

number

[0057] In the above formula (1), E is the modulus of longitudinal elasticity, and ν is the Poisson's ratio.

[0058] Here, the strain energy release rate of the epoxy resin constituting the matrix resin 124 is, for example, 330 J / m 2 More than 800J / m 2 The following is the result.

[0059] In contrast, the strain energy release rate of the material constituting the multiple elastic particles 126 is, for example, 1500 J / m 2 More than 10000J / m 2 The strain energy release rate of the elastic particles 126 is 1500 J / m 2 By setting the elasticity to 10000 J / m or more, bending of the core wire 120 can be stably tolerated. 2 By setting the thickness of the core wire 120 to the above range, it is possible to prevent the tensile strength of the core wire 120 from decreasing.

[0060] In this embodiment, each of the elastic particles 126 contains at least one of a thermosetting elastomer (rubber) and a thermoplastic elastomer, for example. This allows the elastic particles 126 to satisfy the above-mentioned Young's modulus or strain energy release rate.

[0061] Examples of thermosetting elastomers (rubber) that make up the elastic particles 126 include natural rubber (NR), silicone rubber (SI), fluororubber (FKM), styrene rubber (SBR), butadiene rubber (BR), ethylene propylene rubber (EPM), ethylene propylene diene rubber (EPDM), urethane rubber (U), acrylic rubber (ACM), and butyl rubber (BR).

[0062] Examples of thermoplastic elastomers that make up the elastic particles 126 include olefin-based elastomers (TPO, TPV), styrene-based elastomers (TPS), urethane-based elastomers (TPU), ester-based elastomers (TPC, TPEE), polyvinyl chloride-based elastomers (TPVC), and amide-based elastomers (TPAE).

[0063] Among these materials, two or more kinds may be used in combination.

[0064] In this embodiment, the volume average particle size of each of the multiple elastic particles 126 is, for example, not less than 10 μm and not more than 100 μm.

[0065] The "volume average particle size (MV)" here refers to the particle size of the particles d i , the volume of the particle V i Then, it can be calculated by the following formula: MV = Σ(V i d i ) / ΣV i The volume average particle size is measured using a dynamic light scattering particle size / particle size distribution measuring device.

[0066] By setting the volume average particle diameter of the elastic particles 126 to 10 μm or more, it is possible to ensure the flexibility of the elastic particles 126 themselves in the matrix resin 124. On the other hand, by setting the volume average particle diameter of the elastic particles 126 to 100 μm or less, it is possible to stably disperse a plurality of elastic particles 126 in the matrix resin 124.

[0067] In this embodiment, the content of the multiple elastic particles 126 in the core wire 120 is, for example, 5% by mass or more and 25% by mass or less. The entire core wire 120 is taken as 100% by mass.

[0068] By setting the content of the elastic particles 126 to 5% by mass or more, it is possible to stably tolerate bending of the core wire 120. On the other hand, by setting the content of the elastic particles 126 to 25% by mass or less, it is possible to suppress deterioration of the mechanical properties of the power transmission cable 10 caused by excessive elastic particles 126.

[0069] In this embodiment, the multiple elastic particles 126 may be uniformly dispersed within the core wire 120 .

[0070] Specifically, the core wire 120 of the present embodiment satisfies, for example, the following formula (1). 0.8≦B / A≦1.2 (1)

[0071] 2, when a cross section including (along) the central axis CA of the core wire 120 is observed, A is the ratio of the total area of ​​the elastic particles 126 in the inner region to the area of ​​the inner region from the central axis CA of the core wire 120 to a position of diameter Φ / 2 in the cross section. B is the ratio of the total area of ​​the elastic particles 126 in the outer region to the area of ​​the outer region located outside the inner region in the cross section, where Φ is the overall diameter of the core wire 120.

[0072] When B / A≧0.8, it is possible to ensure bendability in the outer region of the core wire 120 while suppressing an excessive decrease in the mechanical properties in the inner region of the core wire 120. On the other hand, when B / A≦1.2, it is possible to ensure bendability in the inner region of the core wire 120 while suppressing an excessive decrease in the mechanical properties in the outer region of the core wire 120.

[0073] (covering layer) In this embodiment, the central portion 100 may have, for example, a coating layer 140. The coating layer 140 is provided, for example, so as to cover the outer periphery of the core wire 120. The coating layer 140 includes, for example, a metal. The coating layer 140 can protect the core wire 120.

[0074] An example of the metal constituting the coating layer 140 is aluminum (Al). This makes it possible to suppress electrolytic corrosion of the outer strand 320 caused by contact between the core wire 120 and the outer strand 320.

[0075] The coating layer 140 may be composed of multiple layers, for example. In this case, the coating layer 140 may have, for example, a first coating layer containing a metal and a second coating layer containing a resin, in that order from the center 100 toward the outside in the radial direction. Examples of the resin constituting the second coating layer include thermosetting epoxy resin.

[0076] (3) Manufacturing method of power transmission lines Next, a method for manufacturing the power transmission line 10 according to this embodiment will be described.

[0077] The method for manufacturing the power transmission cable 10 of the present embodiment includes, for example, a preparation step S10, a central portion forming step S20, and an outer stranded layer forming step S30.

[0078] (S10: Preparation process) First, the carbon fibers 122, matrix resin 124, and elastic particles 126 that constitute the central portion 100 are prepared.

[0079] Also, the outer strand 320 constituting the outer stranded wire layer 300 is prepared. Specifically, the outer strand 320 is formed by drawing a predetermined aluminum alloy material using a wire drawing machine equipped with a die having a sector-shaped opening.

[0080] (S20: Center forming process) Next, the central portion 100 is formed. The central portion forming step S20 of this embodiment includes, for example, a core wire forming step S22 and a coating layer forming step S24.

[0081] (S22: Core wire forming process) First, the core wire 120 is formed.

[0082] In this embodiment, a matrix resin 124 is formed so as to cover the multiple carbon fibers 122, while multiple elastic particles 126 that are softer than the matrix resin 124 are dispersed among the multiple carbon fibers 122 in the matrix resin 124. In this way, the core wire 120 including the multiple carbon fibers 122 is configured so that the neutral axis of the core wire 120 shifts from the central axis CA of the core wire 120 to each central axis of the multiple carbon fibers 122 when the power transmission cable 10 is bent.

[0083] Specifically, a resin tank is filled with matrix resin 124. At this time, elastic particles 126 are added to matrix resin 124. Next, carbon fibers 122 are impregnated into matrix resin 124 to which elastic particles 126 have been added in the resin tank. At this time, an ultrasonic vibrator provided in the resin tank vibrates matrix resin 124 so that elastic particles 126 are uniformly dispersed in matrix resin 124. After the vibration treatment of matrix resin 124, a mold is used to mold core wire 120 having a predetermined diameter. Then, core wire 120 is hardened in a hardening furnace. In this manner, the above-mentioned core wire 120 is formed.

[0084] (S24: Covering layer formation step) After the core wire forming step S22 is completed, a coating layer 140 containing a metal is formed so as to cover the outer circumference of the core wire 120. As the coating layer 140, a first coating layer containing a metal and a second coating layer containing a resin may be formed in this order from the center portion 100 toward the outside in the radial direction. The coating layer containing a metal layer (coating layer 140 or first coating layer) is formed, for example, by an extrusion process. The second coating layer containing a resin is formed, for example, by a pultrusion molding process.

[0085] (S30: External twisted wire layer formation process) Next, the outer stranded wire layer 300 is formed by a predetermined stranding machine.

[0086] Specifically, first, a first stranding machine is used to strand a plurality of outer strands 320 so as to surround the outer periphery of the core 100, thereby forming a first outer stranded wire layer 300a.

[0087] Next, a second stranding machine is used to strand a plurality of outer strands 320 so as to surround the outer periphery of first outer stranded wire layer 300a, thereby forming second outer stranded wire layer 300b.

[0088] In this manner, the power transmission line 10 according to the present embodiment is manufactured.

[0089] (4) Summary of this embodiment According to this embodiment, one or more of the following advantages are achieved.

[0090] (a) In this embodiment, a plurality of elastic particles 126 that are softer than the matrix resin 124 are dispersed among a plurality of carbon fibers 122 in the matrix resin 124 .

[0091] Since the core wire 120 includes the above-mentioned multiple elastic particles 126, when the power transmission cable 10 is bent, the core wire 120 can be elastically deformed (flexibly stretched and contracted) at each location including the elastic particles 126. This allows the core wire 120 to be configured such that, when the power transmission cable 10 is bent, the neutral axis of the core wire 120 shifts from the central axis CA of the core wire 120 to each central axis of the multiple carbon fibers 122. In other words, the neutral axis of the core wire 120 at which the stress is zero can be dispersed to the central axes of the multiple carbon fibers 122 scattered throughout the core wire 120.

[0092] By shifting the neutral axis of the core wire 120 as described above, it is possible to reduce the bending stress applied to the matrix resin 124 even at a position radially away from the central axis CA of the core wire 120, and to suppress the occurrence of cracks in the matrix resin 124. This allows bending of the core wire 120 as a whole while maintaining the shape of the core wire 120. Specifically, it is possible to reduce the bending radius at which the core wire 120 breaks to, for example, the bending radius at which each carbon fiber 122 breaks.

[0093] As a result, breakage of the power transmission line 10 can be avoided under various circumstances.

[0094] For example, when the power transmission line 10 is stringed, even when the power transmission line 10 is passed through a pulley having a diameter of several hundred mm to 1 m, breakage of the power transmission line 10 can be avoided. Alternatively, even if the power transmission line 10 is subjected to bending stress near accessories such as clamps, straight sleeves, and spacers due to galloping or heavy snow accumulation after the power transmission line 10 is stringed, breakage of the power transmission line 10 can be avoided.

[0095] (b) In this embodiment, the matrix resin 124 itself is not made flexible, but the flexible elastic particles 126 are dispersed in the matrix resin 124, thereby making it possible to sufficiently ensure the performance of the matrix resin 124 itself. This makes it possible to maintain the tensile strength, elastic modulus, and heat resistance of the core wire 120 at the same levels as when the core wire 120 does not have the elastic particles 126.

[0096] <Other embodiments of the present disclosure> Although the embodiments of the present disclosure have been specifically described above, the present disclosure is not limited to the above-described embodiments and can be modified in various ways without departing from the spirit and scope of the present disclosure.

[0097] In the above embodiment, the case where the central portion 100 has one core wire 120 has been described. However, the central portion 100 may have, for example, a plurality of core wires 120.

[0098] In the above embodiment, the case where two outer stranded wire layers 300 are provided has been described, but only one outer stranded wire layer 300 or three or more outer stranded wire layers 300 may be provided.

[0099] In the above embodiment, the outer stranded wire layer 300 has an outer stranded wire 320 with a sector-shaped cross section. However, at least a part of the outer stranded wires 320 may have a circular cross section. EXAMPLES

[0100] Next, examples according to the present disclosure will be described. These examples are merely examples of the present disclosure, and the present disclosure is not limited to these examples.

[0101] (1) Core wire manufacturing The following two core wires were manufactured:

[0102] (Sample A) A core wire was formed by the above-mentioned manufacturing method under the following conditions. Carbon fiber: elongation 2.1% Matrix resin: Thermosetting epoxy resin Elastic particle material: Ethylene propylene rubber Volume average particle size of elastic particles: Approximately 50 μm Elastic particle content: 15% by mass Core wire diameter: 6.00mm

[0103] (Sample B) A core wire was manufactured similarly to sample A, except that no elastic particles were added to the core wire.

[0104] (2) Evaluation The following evaluations were carried out on the two core wires mentioned above.

[0105] (Cross-section observation of the core wire of sample A) The core wire of sample A was cut along the central axis with a refine cutter. The cross section of the core wire was then observed with a scanning electron microscope. From this, the ratio B / A was calculated. Here, A is the ratio of the total area of ​​the multiple elastic particles in the inner region to the area of ​​the inner region from the central axis of the core wire to a position 3.0 mm in diameter in the cross section. B is the ratio of the total area of ​​the multiple elastic particles in the outer region to the area of ​​the outer region located outside the inner region in the cross section.

[0106] (Core wire bending test) A test was conducted in which each of the core wires of samples A and B was wound 180° around a cylindrical mandrel. The bending radius of the core wire was determined when at least a portion of the core wire was damaged (i.e., when it broke) by winding the core wire around the cylindrical mandrel.

[0107] (3) Results; (Cross-section observation of core wire of sample A) As a result of observing the cross section of the core wire of sample A, the ratio B / A of the elastic particles in the outer region of the core wire to the inner region of the core wire was 1.1. In other words, it was confirmed that the elastic particles were uniformly dispersed in the core wire of sample A.

[0108] (Core wire bending test results) A bending test was conducted on the core wire of Sample B, and the bending radius at which the core wire of Sample B broke was approximately 150 mm. After the bending test, cracks appeared in the matrix resin of the core wire of Sample B, and some of the carbon fibers were scattered from the core wire.

[0109] In Sample B, the neutral axis of the core wire coincided with the central axis of the core wire. Therefore, the bending stress applied to the matrix resin was large at a position away from the central axis of the core wire of Sample B. As a result, it is believed that the core wire of Sample B broke.

[0110] In contrast, a bending test of the core wire of sample A showed that the core wire did not break even when the bending radius of the core wire of sample A was approximately 1 mm.

[0111] In sample A, since the core wire contains the above-mentioned multiple elastic particles, when the core wire is bent, the neutral axis of the core wire can be shifted from the central axis of the core wire to the central axis of each of the multiple carbon fibers. As a result, it was confirmed that breakage of the core wire could be avoided in sample A. [Explanation of symbols]

[0112] 10. Power Lines 100 center 120 core wire 122 Carbon Fiber 124 Matrix Resin 126 Elastic Particles 140 Covering layer 300 external strand layer 300a 1st outer strand layer 300b 2nd outer strand layer 320 Outer wire CA center axis

Claims

1. A power transmission line, a central portion having a core wire; an outer stranded wire layer provided by stranding a plurality of outer wires so as to surround an outer periphery of the central portion; Equipped with The core wire is A plurality of carbon fibers; A matrix resin covering the plurality of carbon fibers; a plurality of elastic particles dispersed among the plurality of carbon fibers in the matrix resin and being softer than the matrix resin; Equipped Power line.

2. The core wire is configured such that, when the power transmission line is bent, a neutral axis of the core wire shifts from a central axis of the core wire to a central axis of each of the plurality of carbon fibers.

2. The power transmission line of claim 1.

3. The material constituting the elastic particles has a modulus of longitudinal elasticity lower than the modulus of longitudinal elasticity of the matrix resin. The power transmission line according to claim 1 or 2.

4. The material constituting the elastic particles has a modulus of longitudinal elasticity of 1 MPa or more and 100 MPa or less at 25°C. The power transmission line according to claim 1 or 2.

5. The strain energy release rate of the material constituting the plurality of elastic particles is higher than the strain energy release rate of the matrix resin. The power transmission line according to claim 1 or 2.

6. The strain energy release rate of the material constituting the plurality of elastic particles is 1500 J / m ２ More than 10000J / m ２ is less than or equal to The power transmission line according to claim 1 or 2.

7. Each of the plurality of elastic particles includes at least one of a thermosetting elastomer and a thermoplastic elastomer. The power transmission line according to claim 1 or 2.

8. The volume average particle size of each of the plurality of elastic particles is 10 μm or more and 100 μm or less. The power transmission line according to claim 1 or 2.

9. The content of the plurality of elastic particles in the core wire is 5% by mass or more and 25% by mass or less. The power transmission line according to claim 1 or 2.

10. The core wire satisfies the following formula (1): 0.8≦B / A≦1.2 (1) Where: When a cross section including the central axis of the core wire is observed, A is a ratio of a total area of ​​the plurality of elastic particles in the inner region to an area of ​​the inner region from the central axis of the core wire to a position of diameter Φ / 2 in the cross section, B is a ratio of the total area of ​​the elastic particles in the outer region to the area of ​​the outer region located outside the inner region in the cross section, Φ is the overall diameter of the core wire The power transmission line according to claim 1 or 2.

11. The central portion further includes a coating layer that covers the outer periphery of the core wire and contains a metal. The power transmission line according to claim 1 or 2.

12. The power transmission line according to claim 1 or 2 is used. Core wire.

13. A method for manufacturing a power transmission line, comprising: forming a core; forming an outer stranded layer by stranding a plurality of outer wires around an outer periphery of the central portion; Equipped with The step of forming the central portion includes the step of forming a core wire, The step of forming the core wire includes: Providing a plurality of carbon fibers; forming a matrix resin so as to cover the carbon fibers, and dispersing a plurality of elastic particles, which are softer than the matrix resin, among the carbon fibers in the matrix resin; Equipped Methods for manufacturing power lines.

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