Electric wire with shielding part

Abstract

The present disclosure provides a shielded electric wire having excellent vibration resistance. An electric wire with a shield includes: an inner conductor; an insulator disposed outside the inner conductor; a shield conductor disposed outside the insulator; and a sheath disposed outside the shield conductor, the cross-sectional area of the inner conductor being 3 mm2 or more and 160 mm2 or less, the insulator containing a polyolefin as a resin, and the sheath containing a polyurethane as a resin.

Description

Technical Field

[0001] The present disclosure relates to an electric wire with a shielding portion. Background Art

[0002] Patent Document 1 discloses a cable in which the outer periphery of a conductor is coated with an insulating resin containing a flame retardant, and further discloses that a shield conductor is disposed on the outer periphery of the insulating resin and the outer periphery of the shield conductor is coated with the insulating resin.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2014-139932

[0006] Since vibrations are continuously applied to automobiles while they are running, electric wires mounted in automobiles are required to have vibration resistance that can suppress abrasion of the outer covering and a decrease in withstand voltage characteristics when vibrations are repeatedly applied. Summary of the invention

[0007] An object of the present disclosure is to provide an electric wire with a shield portion having excellent vibration resistance.

[0008] The shielded wire of the present disclosure comprises: an inner conductor; an insulator disposed outside the inner conductor; a shield conductor disposed outside the insulator; and an outer sheath disposed outside the shield conductor, wherein the cross-sectional area of ​​the inner conductor is 3 mm 2 Above and 160mm 2 Hereinafter, the insulator contains polyolefin as the resin, and the sheath contains polyurethane as the resin.

[0009] Effects of the Invention

[0010] According to the present disclosure, it is possible to provide an electric wire with a shield portion that is excellent in vibration resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a cross-sectional view of a shielded electric wire according to one embodiment of the present disclosure, taken along a plane perpendicular to the longitudinal direction.

[0012] Description of Reference Numerals

[0013] 10: Electric wire (electric wire with shielding part)

[0014] 11: Inner conductor

[0015] 12: Insulator

[0016] 12A: Outer periphery of insulator

[0017] 13: Shielded conductor

[0018] 14: Skin

[0019] 14A: Outer periphery of the skin

[0020] D11: The outer diameter of the inner conductor

[0021] D12: The outer diameter of the insulator

[0022] T12: Thickness of the insulation. DETAILED DESCRIPTION

[0023] Hereinafter, specific implementation methods will be described.

[0024] [Description of Embodiments of the Present Disclosure]

[0025] First, the embodiments of the present disclosure will be described by way of example. In the following description, the same reference numerals are given to the same or corresponding elements, and the same description thereof will not be repeated.

[0026] (1) An electric wire with a shield according to one embodiment of the present disclosure comprises: an inner conductor; an insulator disposed outside the inner conductor; a shield conductor disposed outside the insulator; and an outer sheath disposed outside the shield conductor, wherein the cross-sectional area of ​​the inner conductor is 3 mm 2 Above and 160mm 2 Hereinafter, the insulator contains polyolefin as the resin, and the sheath contains polyurethane as the resin.

[0027] By setting the cross-sectional area of ​​the inner conductor to 3mm 2 As described above, the resistance of the internal conductor can be suppressed, and a high current can be supplied.

[0028] By setting the cross-sectional area of ​​the inner conductor to 160mm 2 As a result, the flexibility of the internal conductor and the electric wire with a shield including the internal conductor (hereinafter, also simply described as “electric wire”) can be improved, and the weight of the electric wire can be reduced.

[0029] The insulator contains polyolefin as the resin, thereby improving the flexibility of the electric wire.

[0030] The outer sheath contains polyurethane as the resin, thereby improving the vibration resistance of the electric wire.

[0031] (2) In the above (1), the outer cover and the insulator may contain a flame retardant.

[0032] The sheath and the insulation contain a flame retardant, thereby improving the flame retardancy of the electric wire.

[0033] (3) In the above (1) or (2), the polyurethane of the outer skin may be cross-linked.

[0034] The polyurethane of the sheath is cross-linked, thereby improving the heat resistance of the sheath and the electric wire.

[0035] (4) In any one of the above (1) to (3), the polyolefin of the insulator may be cross-linked.

[0036] The polyolefin of the insulation is cross-linked, thereby improving the heat resistance of the insulation and the electric wire.

[0037] (5) In any one of the above (1) to (4), in a cross section perpendicular to the longitudinal direction, the outer periphery of the insulator and the outer periphery of the outer skin may be arranged to form concentric circles.

[0038] In a cross section perpendicular to the longitudinal direction, the outer periphery of the insulator and the outer periphery of the sheath are arranged to form concentric circles, whereby the shielded electric wire according to one aspect of the present disclosure can be suitable for use with a rated voltage of several hundred volts.

[0039] (6) In any one of the above (1) to (5), the thickness of the insulator may be 0.4 mm or more.

[0040] By setting the thickness of the insulator to 0.4 mm or more, the withstand voltage characteristics of the shielded electric wire can be improved.

[0041] [Details of the embodiments of the present disclosure]

[0042] Hereinafter, a specific example of an electric wire with a shield portion according to an embodiment of the present disclosure (hereinafter referred to as "this embodiment") will be described with reference to the accompanying drawings. It should be noted that the present invention is not limited to these examples, but is indicated by the claims, and is intended to include all changes within the meaning and scope equivalent to the claims.

[0043] [Shielded electric wire]

[0044] Figure 1 2 shows an example of a cross-section perpendicular to the longitudinal direction of the electric wire with a shield according to the present embodiment. Figure 1 In FIG. 1 , the length direction of the wire 10 is along the Z axis, which is the axis perpendicular to the paper. Figure 1 , a cross section at an XY plane perpendicular to the Z axis is shown.

[0045] like Figure 1 As shown, the electric wire 10 of the present embodiment includes an inner conductor 11 , an insulator 12 disposed outside the inner conductor 11 , a shield conductor 13 disposed outside the insulator 12 , and a sheath 14 disposed outside the shield conductor 13 .

[0046] (1) About the components included in the electric wire

[0047] Each member included in the electric wire of this embodiment will be described.

[0048] (1-1) Internal conductor

[0049] Figure 1 This is a schematic diagram, and thus the internal conductor 11 is represented by a circle, but the present invention is not limited to this form.

[0050] The inner conductor 11 may include a single conductor wire or a plurality of conductor wires.

[0051] The cross-sectional shape of the internal conductor 11 is not particularly limited, and for example, a plane perpendicular to the longitudinal direction may be a circle such as a perfect circle or an ellipse, or may be a polygon such as a quadrilateral.

[0052] From the viewpoint of improving the handling property during wiring, etc., the electric wire 10 may be required to be flexible, which is a property that can be easily bent. When the electric wire 10 is required to be flexible, the internal conductor 11 may be a stranded wire formed by twisting a plurality of conductor wires. When the internal conductor 11 includes a stranded wire formed by twisting a plurality of conductor wires, the number of conductor wires included in the internal conductor 11 and the conditions for twisting are not particularly limited and can be selected according to the conductor cross-sectional area required for the internal conductor 11.

[0053] The material of the internal conductor 11 is not particularly limited, and for example, one or more conductor materials selected from copper alloy, copper, silver-plated annealed copper, and tin-plated annealed copper can be used. For example, annealed copper can be used as copper.

[0054] The cross-sectional area of ​​the internal conductor 11 is not particularly limited, and the cross-sectional area of ​​the internal conductor 11 can be set to 3 mm 2 Above, can also be set to 8mm 2 By setting the cross-sectional area of ​​the internal conductor 11 to 3 mm 2 As described above, the resistance of the internal conductor 11 can be suppressed, and a high current can be supplied.

[0055] The upper limit of the cross-sectional area of ​​the internal conductor 11 is not particularly limited, and the cross-sectional area of ​​the internal conductor 11 may be 160 mm 2 By setting the cross-sectional area of ​​the internal conductor 11 to 160 mm 2 As a result, the flexibility of the internal conductor 11 and the electric wire 10 including the internal conductor 11 can be improved, and the weight of the electric wire 10 can be reduced.

[0056] As mentioned above, the cross-sectional area of ​​the inner conductor 11 can be set to 3 mm 2 Above and 160mm 2 Below, 8mm is also possible 2 Above and 160mm 2the following.

[0057] When the internal conductor 11 is a stranded wire, the cross-sectional area of ​​the internal conductor 11 can be evaluated by the following procedure.

[0058] First, the wire diameter of the conductor wire included in the internal conductor 11 is measured. Then, the cross-sectional area of ​​the conductor wire obtained from the wire diameter is multiplied by the number of conductor wires included in the internal conductor 11 to obtain the cross-sectional area of ​​the internal conductor 11.

[0059] When the internal conductor 11 is a single wire, the cross-sectional area of ​​the internal conductor 11 is obtained from the measured outer diameter D11 of the internal conductor 11 .

[0060] In any cross section perpendicular to the length direction of the conductor wire, two orthogonal diameters are measured and the two measured diameters are averaged to obtain the wire diameter. When the internal conductor 11 is a single wire, the outer diameter D11 of the internal conductor 11 is obtained by the same process as the wire diameter except that the internal conductor 11 is used as the measurement object.

[0061] (1-2) Insulator

[0062] like Figure 1 As shown, the insulator 12 may cover the outer surface of the inner conductor 11. The insulator 12 may include a resin.

[0063] (1-2-1) Resin

[0064] The insulator 12 may contain polyolefin as the resin. When the insulator 12 contains polyolefin as the resin, the flexibility of the electric wire 10 can be improved.

[0065] For example, as the polyolefin, one or more copolymers selected from homopolymers such as low-density polyethylene (LDPE), linear low-density polyethylene (L-LDPE), and ultra-low-density polyethylene (VLDPE), and copolymers such as ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), and ethylene-vinyl acetate copolymer (EVA) introduced with other polar monomers other than α-olefin to impart flexibility to the resin can be used.

[0066] As described above, the insulator 12 may use EEA as a polyolefin, for example. EEA has a low crystallinity due to the ethyl acrylate (EA) contained therein, and has high flexibility. In addition, the thermal decomposition start temperature of EEA is as high as 300°C. Among polyolefins, EEA has high long-term heat aging resistance and can be used for a long time as an electric wire that generates heat when powered. In addition, EEA easily forms a carbonized layer when burning, and the carbonized layer isolates oxygen to hinder combustion, thereby reducing the amount of flame retardant added, making it easy to achieve high flame retardancy with a low specific gravity.

[0067] The content of the comonomer in the resin can be set to, for example, 23% by weight or more, thereby suppressing the crystallinity and improving the flexibility of the insulator 12 and the wire 10. The resin contained in the insulator 12 may be a copolymer of an olefin and a polar comonomer or a mixture of the copolymer and an olefin and an α-olefin copolymer.

[0068] (1-2-2) Flame retardant

[0069] The insulator 12 may contain a flame retardant. When the insulator 12 contains a flame retardant, the flame retardancy of the insulator 12 and the electric wire 10 can be improved.

[0070] As the flame retardant, one or more selected from non-halogen flame retardants and halogen flame retardants can be used.

[0071] Examples of the non-halogen flame retardant include metal hydroxides (magnesium hydroxide, etc.), nitrogen flame retardants (melamine cyanurate, etc.), antimony trioxide, and phosphorus flame retardants (red phosphorus, phosphate esters, etc.).

[0072] Examples of halogen-based flame retardants include bromine-based flame retardants.

[0073] In this specification, flame retardancy can be evaluated by the 45-degree inclined flame retardancy test of ISO196472 standard. As the process of the 45-degree inclined flame retardancy test, first, a wire cut into 600mm is used as a sample, and the sample is fixed at an angle of 45 degrees relative to the horizontal plane. Then, the flame of a gas burner is contacted at a position 500mm from the upper end of the above-mentioned sample, and the flame contact is terminated after the conductor is exposed or after 30 seconds. Then, the time from the end of the flame contact to the sample self-extinguishing is measured, and the situation that the self-extinguishing within 70 seconds and the insulator has more than 50mm remaining from the upper end of the sample is set as qualified, and it can be judged that it has flame retardancy. The situation that the self-extinguishing is not within 70 seconds or the situation that the insulator does not have more than 50mm remaining from the upper end of the sample is set as unqualified, and it can be judged that it does not have flame retardancy.

[0074] (1-2-3) Other added ingredients

[0075] In addition to resin and flame retardant, the insulator 12 may contain one or more additive components selected from antioxidants, anti-degradation agents, acid absorbers, colorants, crosslinking agents, crosslinking aids, processing aids, fillers, lubricants, and the like.

[0076] The insulator 12 can be formed by adding a flame retardant or other additives to a resin as necessary and performing extrusion molding on the outer periphery of the internal conductor 11 .

[0077] The polyolefin of the insulator 12 may be cross-linked by irradiation with ionizing radiation (gamma rays, electron beams, etc.), peroxide cross-linking, silane cross-linking, or other chemical cross-linking after being coated on the outer surface of the internal conductor 11 .

[0078] The polyolefin of the insulator 12 may or may not be crosslinked. When the polyolefin of the insulator 12 is crosslinked, the heat resistance of the insulator 12 and the electric wire 10 can be improved.

[0079] The thickness T12 of the insulator 12 is not particularly limited, and may be, for example, 0.32 mm or more, or 0.4 mm or more.

[0080] By setting the thickness T12 of the insulator 12 to be 0.32 mm or more, and particularly to be 0.4 mm or more, the withstand voltage characteristics of the shielded electric wire can be improved.

[0081] The upper limit of the thickness T12 of the insulator 12 is not particularly limited, and can be set to 1.6 mm or less, for example. By setting the thickness T12 of the insulator 12 to 1.6 mm or less, the shielded wire can be made lighter and the shielded wire can be easily bent. Therefore, the handling of the shielded wire can be improved. The thickness T12 of the insulator 12 can be selected according to the cross-sectional area of ​​the internal conductor 11. For example, when the cross-sectional area of ​​the internal conductor 11 is 160 mm, the thickness T12 of the insulator 12 can be set to 1.6 mm or less. 2 In this case, the thickness T12 of the insulator 12 can be set to 1.6 mm.

[0082] Therefore, the thickness T12 of the insulator 12 may be, for example, not less than 0.32 mm and not more than 1.6 mm, or not less than 0.4 mm and not more than 1.6 mm.

[0083] The thickness T12 of the insulator 12 is obtained by subtracting the outer diameter D11 of the internal conductor 11 from the outer diameter D12 of the insulator 12 and dividing the result by 2. The outer diameter D12 of the insulator 12 and the outer diameter D11 of the internal conductor 11 are obtained by the same process as that of the wire diameter described in the section on the internal conductor, except that the measurement objects are the insulator 12 and the internal conductor 11, and therefore the description thereof is omitted.

[0084] (1-3) Shielded conductor

[0085] The electric wire 10 of the present embodiment may include a shield conductor 13 disposed outside the insulator 12 .

[0086] The shield conductor 13 may include a conductive material.

[0087] The shield conductor 13 may be formed by spirally winding a conductive tape including a conductive layer along the longitudinal direction of the inner conductor 11 , for example.

[0088] In this case, the conductive tape may include a base member and a conductive layer disposed on at least one of the upper surface and the lower surface of the base member. The conductive tape may also include a conductive layer on both the upper surface and the lower surface of the base member. In addition, the conductive tape may not include a base member but may be composed only of a conductive layer.

[0089] The material of the conductive layer is not particularly limited, and may include metal, such as metal foil. When the conductive layer includes metal, the material of the metal is not particularly limited, and for example, copper, copper alloy, aluminum, aluminum alloy, etc. may be used.

[0090] The material of the base member is not particularly limited, and may include, for example, insulating materials such as organic polymer materials and nonwoven fabrics. Examples of organic polymer materials include polyester resins such as polyethylene terephthalate (PET), polyolefin resins such as polypropylene, and vinyl resins such as polyvinyl chloride. The base member may include a base member including an insulating material or a base member consisting only of an insulating material.

[0091] The shield conductor 13 may also be formed by a metal wire. In this case, the shield conductor 13 may be formed by winding the metal wire laterally, or by weaving the metal wire. Copper, aluminum, copper alloy, etc. may be used as the material of the metal wire. The surface of the metal wire may be plated with silver or tin. Therefore, for example, a silver-plated copper alloy, a tin-plated copper alloy, etc. may be used as the metal wire.

[0092] Since the shield conductor 13 is formed by braiding metal wires, the flexibility of the electric wire 10 can be improved.

[0093] The shield conductor 13 may have not only one layer but also multiple layers. When the shield conductor 13 has multiple layers, for example, it may have a first shield conductor obtained by spirally winding a conductive tape along the length direction of the inner conductor 11 and a second shield conductor obtained by horizontally winding a metal wire or braiding a metal wire. It should be noted that the first and second of the first shield conductor and the second shield conductor are given for distinguishing the components and do not indicate priority, arrangement, etc.

[0094] The electric wire 10 includes the shield conductor 13 , thereby making it possible to suppress leakage of signals from the electric wire 10 to the outside and intrusion of radio waves such as signals transmitted from the outside to the electric wire 10 .

[0095] (1-4) Skin

[0096] The outer sheath 14 may be disposed outside the shield conductor 13 .

[0097] The electric wire 10 has a sheath 14, thereby protecting the internal conductor 11 and the shield conductor 13. The sheath 14 may contain a resin.

[0098] (1-4-1) Resin

[0099] The outer skin 14 may contain polyurethane as the resin.

[0100] The polyurethane is not particularly limited, and for example, an ether-based polyurethane elastomer can be used. The properties of the polyurethane are also not particularly limited, and for example, a polyurethane having a Shore A hardness of 80 or more and 95 or less can be used. In particular, from the viewpoint of improving strength and properties at low temperatures, a polyurethane having a Shore A hardness of about 85, for example, 83 or more and 87 or less can be used.

[0101] Conventional shielded electric wires generally use polyolefin as the resin in the outer sheath. Shielded electric wires using polyolefin as the resin in the outer sheath may also have sufficient vibration resistance to meet the standards for shielded electric wires. However, in consideration of the wear of the outer sheath caused by long-term use, shielded electric wires using polyolefin as the resin in the outer sheath are mostly arranged in a tubular protective member for use. When the shielded electric wire is arranged in a tubular protective member, space for the protective member is required when the shielded electric wire is installed. With the development of electrification of automobiles, it is also required to reduce the space for installing electric wires. Therefore, shielded electric wires with further improved vibration resistance are required.

[0102] Therefore, the inventors of the present invention have studied and found that, compared with a shielded electric wire using polyolefin as a resin in the outer sheath, the vibration resistance of the electric wire 10 can be improved by including polyurethane as a resin in the outer sheath 14. In addition, by including polyurethane as a resin in the outer sheath 14, the outer sheath 14 can be made thinner, and the outer diameter of the electric wire 10 can be suppressed, so that the electric wire 10 can be made lighter and more flexible.

[0103] In this specification, the vibration resistance can be measured by testing the vibration frequency at 10 Hz and acceleration at 4.5 G (44.13 m / s) in an environment with a temperature of 60°C. 2 ) and three hours conditions for conducting a vibration test (sine wave constant vibration test) on the shielded wire for evaluation.

[0104] The appearance of the shielded electric wire after the vibration test was visually checked, and a withstand voltage test of 3 kV for one minute was performed. The withstand voltage test can be performed in water at 3 kVAC for one minute according to the method in accordance with 4.6 (withstand voltage) of JIS C 3005 (2014).

[0105] If the result of the appearance test shows that the shielded electric wire after the vibration test completely covers the shielded conductor and passes the withstand voltage test, the shielded electric wire can be evaluated as having excellent vibration resistance.

[0106] If the shielded electric wire after the vibration test shows that part of the outer covering is broken and the shield conductor is exposed as a result of the appearance test or fails the withstand voltage test, it can be evaluated that the shielded electric wire has insufficient vibration resistance.

[0107] (1-4-2) Flame retardant

[0108] The outer sheath 14 may contain a flame retardant. When the outer sheath 14 contains a flame retardant, the flame retardancy of the outer sheath 14 and the electric wire 10 can be improved.

[0109] As the flame retardant, the same material as that described in the insulator 12 can be used, and thus the description thereof will be omitted.

[0110] (1-4-3) Other added ingredients

[0111] The outer cover 14 may contain, in addition to the resin and the flame retardant, an antioxidant, an anti-degradation agent, an acid absorbent, a colorant, a crosslinking agent, a crosslinking aid, a processing aid, a filler, a lubricant and other additives.

[0112] The outer sheath 14 can be formed by adding a flame retardant or other additives to a resin as necessary and performing extrusion molding on the outer periphery of the shield conductor 13 .

[0113] The polyurethane of the sheath 14 may be cross-linked by irradiation with ionizing radiation (gamma rays, electron beams, etc.), chemical cross-linking such as peroxide cross-linking and silane cross-linking after being coated on the outer surface of the shield conductor 13 .

[0114] It should be noted that the polyurethane of the outer sheath 14 may or may not be crosslinked. When the polyolefin of the outer sheath 14 is crosslinked, the heat resistance of the outer sheath 14 and the electric wire 10 can be improved.

[0115] (2) Cross-sectional structure of shielded electric wire

[0116] like Figure 1As shown, in a cross section perpendicular to the longitudinal direction of the electric wire 10 , the outer periphery 12A of the insulator 12 and the outer periphery 14A of the sheath 14 may be arranged to form concentric circles. That is, the insulator 12 and the sheath 14 may be arranged to surround one inner conductor 11 .

[0117] The above arrangement to form concentric circles does not have a strict geometrical meaning, but includes, for example, the following situation: the center of the outer periphery 12A of the insulator 12 and the center of the outer periphery 14A of the outer skin 14 are offset within the range of an error allowed in manufacturing. It should be noted that, regarding the outer periphery 12A of the insulator 12 and the outer periphery 14A of the outer skin 14, when including unevenness, the minimum inclusion circle of the outer periphery 12A of the insulator 12 and the minimum inclusion circle of the outer periphery 14A of the outer skin 14 can be arranged to form concentric circles.

[0118] In a cross section perpendicular to the longitudinal direction of the electric wire 10 , outer periphery 12A of the insulator 12 and outer periphery 14A of the sheath 14 are arranged to form concentric circles, whereby the electric wire 10 of the present embodiment is suitable for use with a rated voltage of several hundred volts.

[0119] [Example]

[0120] Hereinafter, specific examples will be given for description, but the present invention is not limited to these examples.

[0121] (Evaluation method)

[0122] First, a method for evaluating electric wires produced in the following experimental examples will be described.

[0123] (1) Vibration resistance

[0124] The test method for vibration resistance has been described above, so the description of the test method is omitted.

[0125] Regarding the shielded electric wire after the vibration test, if the result of the appearance test showed that the shielded conductor was completely covered by the outer sheath and the withstand voltage test was passed, the shielded electric wire was considered to have excellent vibration resistance and was evaluated as A.

[0126] If the shielded electric wire after the vibration test showed that part of the outer covering was broken and the shielded conductor was exposed or failed the withstand voltage test, the shielded electric wire was considered to have insufficient vibration resistance and was rated as B.

[0127] (2) Flame retardancy test

[0128] The test method of the flame retardancy test has been described above, so the description of the test method is omitted.

[0129] When the flame retardancy test showed that the flame extinguished itself within 70 seconds and the insulation remained 50 mm or more from the upper end of the sample, the shielded electric wire was considered to have flame retardancy and was rated A.

[0130] If the flame retardancy test result showed that the flame did not extinguish itself within 70 seconds or the insulation did not remain 50 mm or more from the upper end of the sample, the shielded electric wire was considered to have insufficient flame retardancy and was rated as B.

[0131] (3) Bending resistance test

[0132] In the bending resistance test, the test method specified in ISO19642-2 was used to investigate the number of times the shielded wire could be bent until it broke. The diameter of the mandrel was 5 times the outer diameter of the shielded wire. The load per cross-sectional area of ​​the internal conductor was 1 kg / mm 2 , the maximum load is set to 12kg. For example, when the cross-sectional area of ​​the internal conductor is 3mm 2 The load is 3 kg. The case where the number of bends before breaking is less than one thousand times is set as C, the case where the number of bends before breaking is greater than or equal to one thousand times and less than five thousand times is set as B, and the case where the number of bends before breaking is greater than or equal to five thousand times is set as A.

[0133] (Electric wire manufacturing conditions)

[0134] Hereinafter, the electric wires in the respective experimental examples will be described. Experimental example 1 is a comparative example, and Experimental examples 2, 3, 4, 5, 6, 7, and 8 are examples.

[0135] [Experimental Examples 1 to 8]

[0136] Production with Figure 1 The evaluation results are shown in Table 1.

[0137] Note that the expression "37 / 65 / 0.26" in the column "Constitution" of the internal conductor shown in Table 1 means that 65 conductor wires having a wire diameter of 0.26 mm are twisted together, and 37 of the twisted wires are further twisted together to form the internal conductor.

[0138] In any of the experimental examples, the insulator 12 includes a resin in which EEA (ethylene-ethyl acrylate copolymer) and PE (polyethylene) are mixed at the same mass ratio as a main component, and further contains a flame retardant. In addition, the resin of the insulator 12 is cross-linked.

[0139] In any of the experimental examples, the shield conductor 13 disposed between the insulator 12 and the outer sheath 14 has a structure in which tinned annealed copper wires are braided.

[0140] In Experimental Example 1, the same resin was used for the insulator 12 and the sheath 14 .

[0141] [Table 1]

[0142]

[0143] As shown in Table 1, it was confirmed that the electric wires of Experimental Examples 2, 3, 4, 5, 6, 7, and 8, in which the outer sheath contained polyurethane as the resin, had excellent vibration resistance regardless of the cross-sectional area of ​​the internal conductor 11. In addition, it was confirmed that the electric wires of Experimental Examples 7 and 8, in which the internal conductor 11 was formed of a copper alloy, had particularly excellent bending resistance.

Claims

1. An electric wire with a shielding portion, comprising: Internal conductor; an insulator, disposed outside the inner conductor; A shielding conductor is arranged outside the insulator; as well as An outer sheath is arranged outside the shielding conductor, The cross-sectional area of ​​the inner conductor is 3 mm 2 Above and 160mm 2 the following, The insulator contains polyolefin as resin, The outer skin contains polyurethane as resin.

2. The shielded electric wire according to claim 1, wherein: The sheath and the insulation contain a flame retardant.

3. The shielded electric wire according to claim 1 or 2, wherein: The polyurethane of the sheath is cross-linked.

4. The shielded electric wire according to claim 1 or 2, wherein: The polyolefin of the insulation is cross-linked.

5. The shielded electric wire according to claim 1 or 2, wherein: In a cross section perpendicular to the longitudinal direction, an outer periphery of the insulator and an outer periphery of the outer skin are arranged to form concentric circles.

6. The shielded electric wire according to claim 1 or 2, wherein: The thickness of the insulator is greater than 0.4 mm.

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