Braided shield and shielded electric wire

Abstract

Provided are: a braided shield in which a decrease in shielding performance due to skipping stitch is suppressed; and a shielded electric wire provided with such a braided shield. The braided shield (3) is formed by braiding a plurality of stranded wires (31), the stranded wires (31) are formed by stranding a plurality of wire rods (30) made of conductive materials, and the stranding pitch of the wire rods (30) in the stranded wires (31) is more than 90 times the layer core diameter of the stranded wires (31). In addition, the shielded electric wire is provided with: an insulated electric wire having a conductor and an insulating layer covering the outer periphery of the conductor; and the braided shield (3) covering the outer periphery of the insulated wire.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a braided shield and a shielded electric wire. BACKGROUND

[0002] In an electric wire typified by a high-voltage electric wire and a communication electric wire, a shield is provided on the outer periphery of one or a plurality of insulated electric wires. The shield functions to block electromagnetic waves intruding from the outside into the electric wire, suppress generation of noise in the electric wire, and block electromagnetic waves released from the electric wire to the outside, thereby suppressing the released electromagnetic waves from causing noise outside. As such a shield, a braided shield composed of a braided body in which a plurality of wire materials are braided is often used. The braided shield is suitable as a shield provided to an electric wire because of its high flexibility and bending resistance. For example, a shielded electric wire provided with a braided shield is disclosed in Patent Literature 1. In addition to being used as a shield provided to the outer periphery of an insulated electric wire in an electric wire, a braided body composed of a metal material is sometimes used as a conductor for power transmission as disclosed in Patent Literature 2. PRIOR ART DOCUMENTS PATENT LITERATURE

[0003] Patent Literature 1: Japanese Patent Application Publication No. 2016-100048 Patent Literature 2: Japanese Patent Application Publication No. 2022-75607 SUMMARY PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] As described above, a braided shield is suitable as a shield for an electric wire because of its high bending resistance and flexibility. In a shielded electric wire in which a braided shield is provided on the outer periphery of an insulated electric wire, if the insulated electric wire is large in diameter, the braided shield also becomes large in size in conjunction therewith. That is, the diameter of the braided shield formed in a cylindrical shape becomes large, and the number of wire materials constituting the braided shield also increases. For example, in a motor vehicle such as an electric motor vehicle, a large-diameter insulated electric wire is used in conjunction with large current, but in conjunction therewith, a large-size braided shield is required.

[0005] A braided shield is generally manufactured in units of a wire bundle in which a plurality of wires are bundled together, by braiding a plurality of wire bundles together. In a braided structure, the number of wires that make up one wire bundle is the number of strands, and the number of wire bundles that are braided is the number of cores, and by increasing the number of strands and / or the number of cores, it is possible to make the braided shield larger. In the case where the number of strands is increased, when braiding the wire bundles to manufacture the braided shield, it is difficult to control the tension applied to each wire that makes up the wire bundle. For example, it is difficult to normally apply tension to some of the wires that make up the wire bundle. As a result, in the braided shield, it is easy for a needle to jump, that is, for a portion of the braided structure to not be properly formed. In detail, when manufacturing the braided shield, each wire bundle is wound on a winding machine, and the wire bundle is unwound from the winding machine while tension is applied to the wire bundle, and the wire bundle is braided using a braiding machine, and at this time, if the tension applied to each wire is not uniform, some of the wires will relax when being unwound, and when the wires are braided together with the other wires to form the wire bundle, it is easy for a needle to jump.

[0006] As a needle to jump, for example, as shown in a braided shield 3' of Figure 3 In the braided shield 3', some of the wires 30 that make up the wire bundle 39 sometimes relax and fly out of the braided structure at an intermediate portion (indicated by reference numeral Al in the drawing). In addition, at the portion where the wires fly out and the surrounding portion, the density of the loops in the braided structure sometimes decreases (indicated by reference numeral A2 in the drawing). In the braided shield, if a needle jumps, there is a possibility that the shielding performance will decrease due to electromagnetic waves passing through the portion where the needle jumped. In addition, if a needle jumps during the manufacture of the braided shield, there is a possibility that the manufacture of the braided structure will not proceed smoothly and that the wires will break due to the wires being caught in the manufacturing device or the like at the portion where the needle jumped. This breakage can also result in a decrease in the shielding performance of the braided shield.

[0007] In view of the above, an object of the present application is to provide a braided shield in which a decrease in shielding performance due to a needle jumping is suppressed, and a shielded electric wire provided with such a braided shield. Approach to solving the problem

[0008] The braided shield of the present disclosure is braided by braiding a plurality of strands, wherein the strands are twisted by twisting a plurality of wires made of an electrically conductive material, and the twist pitch of the wires in the strands is 90 times or more of the layer core diameter of the strands. Effects of the invention

[0009] The braided shield of the present disclosure and the shielded electric wire are a braided shield in which a decrease in shielding performance due to a needle jumping is suppressed, and a shielded electric wire provided with such a braided shield. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1Ais a perspective view showing a braided shield according to an embodiment of the present disclosure. Figure 1B is a side view showing the braided shield. Figure 2 is a perspective view showing a shielded electric wire according to an embodiment of the present disclosure. Figure 3 is a side view showing a configuration in which a needle jump has occurred in a conventional braided shield. DETAILED DESCRIPTION

[0011] [Explanation of Embodiments of the Present Disclosure] First, an embodiment of the present disclosure will be explained. The braided shield and the shielded electric wire of the present disclosure have the following structure.

[0012] [1] The braided shield of the present disclosure is formed by braiding a plurality of strands, wherein the strands are formed by twisting a plurality of wire materials composed of an electrically conductive material, and the twist pitch of the wire materials in the strands is 90 times or more of the layer core diameter of the strands.

[0013] In the above-described braided shield, the plurality of wire materials are not merely provided as a bundle, but are braided to form a braided configuration on the basis of the strands formed by twisting the wire materials. By twisting the wire materials, a needle jump is less likely to occur in the braided shield, and a braided shield in which loops are regularly formed can be formed. It is believed that this is because, when the strands are braided to form the braided configuration, a tension is uniformly applied to each of the wire materials that constitute the strands. On the other hand, by providing the twist pitch of the wire materials in the strands to be 90 times or more of the layer core diameter, the gaps formed between the plurality of strands in the braided configuration are reduced. It is believed that this is the effect of the wire materials that are untwisted due to the untwisting of the strands in the braided configuration occupying the gaps. As the effect of both the suppression of the needle jump and the reduction of the gaps described above, a high shielding performance can be obtained in the braided shield. Even in the case where the braided shield is upsized, by suppressing the needle jump, a reduction in the shielding performance can be suppressed, and the above-described braided shield can be appropriately applied to a large-diameter electric wire such as a large-current electric wire.

[0014] [2] In the above-described [1], the twist pitch of the wire materials in the strands can be 150 times or less of the layer core diameter of the strands. Thus, the effect of suppressing the needle jump that occurs when the braided configuration is formed on the basis of the strands formed by applying the twist to the wire materials is more highly obtained.

[0015] [3] In the manner described in [1] or [2] above, the strands can also be braided with other strands in units of single strands. Thus, by twisting the wire in a layer core diameter of 90 times or more to form a strand and braiding the strand, the effect of improving the shielding performance of the braided shield can be obtained particularly highly.

[0016] [4] The shielded electric wire of the present disclosure has an insulated electric wire having a conductor and an insulating layer covering the outer periphery of the conductor, and the braided shield of any one of [1] to [3] above covering the outer periphery of the insulated electric wire.

[0017] In the shielded electric wire described above, the braided shield provided to the outer periphery of the insulated electric wire is constituted by braiding strands twisted at a prescribed lay length. In the braided shield, the reduction in shielding performance due to the presence of skips and large voids is suppressed, so that noise blocking can be effectively achieved in the shielded electric wire. Even in the case where the braided shield is large, the effect of suppressing the reduction in shielding performance due to skips can be obtained, so that a high shielding performance can be obtained in the shielded electric wire in which the diameter of the insulated electric wire is large, the number of insulated electric wires is large, or the like, in which a large braided shield is required.

[0018] [Details of the Embodiments of the Present Disclosure] Hereinafter, the braided shield and the shielded electric wire of the embodiments of the present disclosure will be described in detail using the drawings. The shielded electric wire of the embodiments of the present disclosure is constituted by the braided shield of the embodiments of the present disclosure.

[0019] <Structure of Shielded Electric Wire> First, the shielded electric wire of one embodiment of the present disclosure will be described. In Figure 2 In the drawing, a shielded electric wire 1 of one embodiment of the present disclosure is represented by a perspective view.

[0020] The shielded electric wire 1 includes an insulated electric wire 2 having a conductor 21 and an insulating layer 22 covering the outer periphery of the conductor 21. Further, as a shield, a braided shield 3 of one embodiment of the present disclosure is provided so as to cover the outer periphery of the insulated electric wire 2.

[0021] The number of the insulated electric wires 2 is not particularly limited and can be one or plural. In the case where plural insulated electric wires 2 are included in the shielded electric wire 1, the braided shield 3 covers the outer periphery of the entire collection of the insulated electric wires 2. The plural insulated electric wires 2 can be constituted in parallel with each other or twisted with each other. In the illustrated form, two insulated electric wires 2 are arranged in parallel with each other.

[0022] Further, in the shielded electric wire 1, a sheath 4 made of an insulating material is optionally provided on the outer periphery of the braided shield 3. Further, the shielded electric wire 1 can have other kinds of shield other than the braided shield 3, optionally on the outer periphery of the insulated electric wire 2. As such a shield, a metal foil can be exemplified. However, as will be described later, the braided shield 3 of the embodiment of the present disclosure can exert a high sealing performance even alone, and can exert a sufficient shielding performance even if it is provided alone as a shield in the shielded electric wire 1.

[0023] The kind, composition, use, and the like of the insulated electric wire 2 are not particularly limited, and various kinds of insulated electric wires 2 can be applied. As a material constituting the conductor 21, various kinds of metal materials represented by copper, copper alloy, aluminum, and aluminum alloy can be used. The conductor 21 is preferably constituted by a stranded wire in which a plurality of wire materials are stranded. The insulating layer 22 is constituted by a material containing an organic polymer. The kind of the organic polymer is not particularly limited, and examples of the organic polymer include polyolefin, olefin-based copolymer, halogen-based polymer such as polyvinyl chloride, fluorine-based polymer, various engineering plastics, elastomer, rubber, and the like. In addition to the organic polymer, an additive can be appropriately contained in the insulating layer 22.

[0024] The size of the insulated electric wire 2 is also not particularly limited. However, as will be described later, even in the case where the braided shield 3 is large-sized, a decrease in the shielding performance is not easily caused, and thus the insulated electric wire 2 is more likely to effectively utilize the high shielding performance of the braided shield 3 in the shielded electric wire 1. For example, the conductor cross-sectional area of the insulated electric wire 2 can be appropriately exemplified as 5 mm 2 The above form. There is no particular upper limit to the conductor cross-sectional area, but it is suppressed to be approximately 200 mm 2 It is preferable that the conductor cross-sectional area be 5 mm

[0025] The sheath 4 functions to insulate the braided shield 3 from the outside and to physically protect the braided shield 3 and the insulated electric wire 2. The braided shield 3 is constituted by a material containing an organic polymer. As the organic polymer constituting the sheath 4, the materials exemplified as the specific examples of the organic polymer constituting the insulating layer 22 can be appropriately applied. In addition to the organic polymer, an additive can be appropriately contained.

[0026] <Structure of Braided Shield> Next, the braided shield 3 of the embodiment of the present disclosure will be described in detail. In the embodiment of the present disclosure, the braided shield 3 is constituted by a plurality of wire materials. The wire materials are not particularly limited, and various kinds of wire materials can be applied. As the wire material, a metal material such as copper, copper alloy, aluminum, and aluminum alloy can be exemplified. In addition to the metal material, a non-metal material such as a resin material can be appropriately contained. Figure 1A In the embodiment of the present disclosure, the braided shield 3 is constituted by a plurality of wire materials. The wire materials are not particularly limited, and various kinds of wire materials can be applied. As the wire material, a metal material such as copper, copper alloy, aluminum, and aluminum alloy can be exemplified. In addition to the metal material, a non-metal material such as a resin material can be appropriately contained. Figure 1BIn the present embodiment, the braided shield 3 is enlarged and represented using a side view. The use of the braided shield 3 is not particularly limited, and can be used as an electromagnetic wave shield in various electric / electronic devices, communication members, and the like, but as explained above, can be particularly suitable for use as a constituent member of the shielded electric wire 1. Hereinafter, the case where the braided shield 3 is used as a constituent member of the shielded electric wire 1 will be mainly assumed.

[0027] In the braided shield 3 of the present embodiment, a plurality of wire members 30 composed of an electrically conductive material are braided. That is, groups of wire members 30 extending in a direction close to the first direction D1 and groups of wire members 30 extending in a direction close to a second direction D2 different from the first direction D1 cross each other and are woven in a mesh shape. The shape of the entire braided shield 3 is not particularly limited, but in the case where the braided shield 3 constitutes the shielded electric wire 1, it is preferable to be braided in a hollow cylindrical shape.

[0028] The constituent material of the wire member 30 constituting the braided shield 3 is not particularly limited as long as it is an electrically conductive material. As the constituent material of the wire member 30, a metal material such as copper or a copper alloy, aluminum or an aluminum alloy, iron or an iron alloy, or a material obtained by plating the surface of these metal materials with tin or the like can be exemplified. The outer diameter of the wire member 30 is not particularly limited, but from the viewpoint of sufficiently improving the flexibility, bending resistance, and shielding performance of the braided shield 3, a range of 0.08 mm or more and 0.50 mm or less can be exemplified.

[0029] As described above, in the braided shield 3, a plurality of wire members 30 constitute groups, and are braided together in units of the groups. Here, in the braided shield 3 of the present embodiment, the wire members 30 constituting each group are not simply bundled, but are twisted together to become a twisted wire 31. That is, a plurality of twisted wires 31 are braided together to constitute the braided shield 3.

[0030] Further, in the braided shield 3 of the present embodiment, the twist pitch of the wire member 30 in the twisted wire 31 constituting the braided structure is 90 times or more the layer core diameter of the twisted wire 31. Here, the layer core diameter of the twisted wire 31 refers to the diameter of a circle passing through the centers of the wire members 30 located at the outermost peripheral portions in the twisted wire 31, and can be estimated as a value obtained by subtracting the outer diameter of one wire member 30 from the outer diameter of the twisted wire 31.

[0031] In the braided shield 3 of the present embodiment, the wire members 30 are not simply bundled, but are braided in a braided shape on the basis of the twisted wire 31, whereby in the braided shield 3, it is difficult to form a skip stitch. The skip stitch refers to a site where a normal braided structure in which loops (sites where the twisted wires 31 cross each other) are regularly formed in a braided body is partially destroyed, for example, a site where a part of the wire members 30 relaxes at an intermediate portion and flies out to the outside of the braided structure (in the case of a shielded electric wire, a site where the braided shield 3 is damaged and the electrically conductive wire 2 is exposed to the outside). Figure 3In the accompanying drawing, reference numeral A1 indicates a configuration where the wires are not twisted, and the coil density decreases at or around this location (in...). Figure 3 (Represented by reference numeral A2 in the accompanying drawings). In the braided shielding 3 of this embodiment, compared to the case where the wires 30 are not twisted, i.e. Figure 3 In the case where the braided shielding 3' shown is braided only as a bundle of wires 39, such skipped stitches are less likely to occur.

[0032] If skipped stitches occur in the braided shielding 3, localized areas of lower wire density will appear, potentially reducing the shielding performance of the braided shielding 3. However, in the braided shielding 3 of this embodiment, skipped stitches are suppressed by using stranded wires 31, thus minimizing such a reduction in shielding performance. By using stranded wires 31 for the wires 30, compared to simply bundling the wires 30 to form the braided structure, a high degree of uniform tension can be applied to each wire 30 during the formation of the braided structure. It is believed that one cause of skipped stitches is the lack of uniform tension application to a portion of the wires 30 during the manufacturing of the braided structure; by using stranded wires, the uniformity of tension is improved, thereby suppressing skipped stitches. In detail, the wires 30 are wound onto a winding machine in the state of being stranded 31, and while being wound out under tension, they are braided using a braiding machine. This allows the braided shielding member 3 of this embodiment to be manufactured. At this time, by applying high uniformity tension to each wire 30 constituting a stranded wire 31, a braided structure that suppresses skipped stitches and has a regular arrangement of coils can be obtained.

[0033] In conventional braided shielding 3', where the wire 30 is simply a bundle of wires 39 to form the braided structure, the larger the braided shielding 3' is, the more prone it is to skipped stitches. However, in the braided shielding 3' of this embodiment, by using stranded wires 31 for the wire 30, even with a larger braided shielding 3', the reduction in shielding performance caused by skipped stitches can be suppressed. By suppressing skipped stitches, the smoothness of the braided structure formation, such as the wire 30 getting stuck at skipped stitch locations, is less likely to be reduced during the manufacturing process of the braided shielding 3', thus maintaining high manufacturability of the braided structure. Consequently, wire breakage and the resulting reduction in shielding performance are also less likely to occur.

[0034] Furthermore, in the braided shielding 3 of this embodiment, as described above, the strand pitch of the wires 30 in the stranded wires 31 is more than 90 times the core diameter of the stranded wires 31. Therefore, the braided shielding 3 becomes a component that, in addition to the aforementioned effect of suppressing skipped stitches, also maintains excellent shielding performance. The reasons are as follows.

[0035] As described above, by forming the braided shield 3 by arranging the wire 30 in the form of the strand 31, occurrence of the needle jump can be suppressed, but if the lay of the wire 30 in the strand 31 is made too small, the shielding performance can not be effectively improved. Or more, the shielding performance can be lower than the case where the wire 30 is not arranged in the form of the strand 31. This is because, if the lay of the strand 31 is reduced and the twisting becomes too strong, the strand 31 as a whole behaves like a thick wire, and thus the gap between the strands 31, that is, the space surrounded by the pair of strands 31 extending in the first direction D1 and the pair of strands 31 extending in the second direction D2, which is not occupied by the strands 31, becomes large. If a large gap is formed in the braided shield 3, electromagnetic waves easily pass through the gap, resulting in a decrease in the shielding performance.

[0036] In contrast, in the braided shield 3 of the present embodiment, the lay of the wire 30 in the strand 31 is increased to 90 times or more of the layer core diameter, and the twisting is suppressed within a range where it does not become too strong. Thus, in the braided structure in which a plurality of strands 31 are braided, the twisted structure is somewhat relaxed, and the wire 30 whose twisting is relaxed occupies the gap between the strands 31. In this way, the gap between the strands 31 is made small by the wire 30 whose twisting is relaxed filling the gap. In the braided shield 3, if the total area of the gaps is reduced, it is difficult for electromagnetic waves to pass through the gaps, and the shielding performance of the braided shield 3, which blocks electromagnetic waves, is highly obtained. From the viewpoint of further improving this effect, it is more preferable that the lay of the wire 30 in the strand 31 be 95 times or more of the layer core diameter. There is no particular upper limit to the lay, but from the viewpoint of improving the effect of suppressing the needle jump by arranging the wire 30 in the form of the strand 31, it is good to suppress the lay to 150 times or less, and further 120 times or less, of the layer core diameter.

[0037] If the lay of the wire 30 in the strand 31 is thus made 90 times or more of the layer core diameter of the strand 31, there is no particular limitation on the length as an absolute value. However, in the case where the outer diameter of the wire 30 is within the appropriate range exemplified earlier, it is preferable to exemplify a way in which the lay of the wire 30 in the strand 31 is 50 mm or more, and further 70 mm or more. It is good to suppress the lay to substantially 120 mm or less.

[0038] In Patent Literature 2, the wires are twisted to form a braided body, but in the embodiment, the lay of the twisted structure is as small as at most 33 times. In Patent Literature 2, the braided body is not used as a shield for electromagnetic wave blocking, but is used as a conductor for power supply. Thus, the method of Patent Literature 2 does not need to suppress the passage of electromagnetic waves by reducing the gap between the strands.

[0039] In the braided shield 3, the details of the configuration and arrangement of the strands 31 are not particularly limited if the strands 31 are formed in a braided configuration by twisting the wire members 30 at a lay of 90 times or more the core diameter. As described above, in the present specification, the lay of the wire members 30 in the strands 31 indicates the period of the twisting of the wire members 30 in the twisted configuration of each strand 31. On the other hand, although the lay in the braided configuration is also mentioned in Patent Literature 1, in Patent Literature 1, the lay is defined as the distance that a bundle of wire members in which a plurality of wire members are arranged relative to each other advances along the length direction of the covered electric wire when the bundle of wire members spirally rotates one turn around the outer periphery of the covered electric wire, which is different from the meaning of the lay in the present specification. In the braided shield 3 of the embodiment of the present disclosure, the lay in the sense of Patent Literature 1, that is, the winding pitch of the configuration in which the strands 31 as a collective body of a plurality of wire members 30 are spirally wound around the outer periphery of the insulated electric wire 2 in the braided configuration, is not particularly limited.

[0040] In addition, in the braided shield 3 of the present embodiment, the twisted configuration and the twisting direction in the strands 31 are not particularly specified. As the twisted configuration, various twisted configurations such as bundle twisting in which all the wire members 30 are randomly concentrated and twisted in the same direction, concentric twisting in which a plurality of wire members 30 are twisted in a concentric manner, and compound twisting in which a plurality of sub-strands are twisted, can be adopted. Among them, from the viewpoint of improving the effect of improving the shielding performance due to the suppression of the skip and the reduction of the void, the bundle twisting is most preferably adopted. As the twisting direction, the twisting directions can be made different from each other between the strands 31 extending along the first direction D1 and the strands 31 extending along the second direction D2, but it is preferable that the twisting direction be made the same in all the strands 31. In addition, in the braided configuration, it is preferable that the strands 31 be braided together with other strands 31 in units of single strands. That is, the braided configuration is not formed in units of a wire group composed of a bundle of a plurality of strands 31, but is formed on the basis of one strand 31 in which all the wire members 30 constituting one wire group are twisted. Thereby, compared to the case where the wire members 30 constituting one wire group are divided into a plurality of strands 31, it is possible to improve the effect of improving the shielding performance by suppressing the skip and reducing the void.

[0041] Various parameters in the braiding of the strands 31, that is, the number of strands, the number of cores, the braiding angle, the braiding density, and the like are not particularly limited. However, from the viewpoint of improving the shielding performance, as well as the flexibility and the bending resistance, of the braided shield 3, the following ranges can be appropriately exemplified. Number of strands (number of wire members 30 included in each strand 31): 3 or more, 50 or less Number of cores (total number of strands 31 constituting the braided shield 3): 4 or more, 130 or less Braiding density (a proportion of an area occupied by the wire 30 on a face of the braided shield 3): 60% or more, 100% or less

[0042] The size of the entire braided shield 3 is appropriately set to be good in accordance with the diameter, the number of strands of the insulated electric wire 2 to be surrounded. In the currently common braided shield 3' in which the wire 30 is set in a bundle to form a braided structure, there is a tendency that the larger the braided shield 3' is made, the more the needle skipping is likely to occur. However, in the braided shield 3 of the present embodiment, the wire 30 is braided into the braided structure in the form of the strand 31, and thus even if the braided shield 3 is made large due to an increase in the number of strands or the like, it is possible to ensure a state in which the equality of the tension applied to each wire 30 at the time of formation of the braided structure is high, and to suppress the needle skipping, thereby obtaining an effect of improving the shielding performance. From the viewpoint of fully enjoying this effect, it is preferable that the braided shield 3 be a large member, and in the hollow cylindrical braided shield 3, for example, it is good that the inner diameter be 4.4 mm or more. There is no particular upper limit to the inner diameter of the braided shield 3, but it is good that it be substantially 26.0 mm or less. Example

[0043] An example is shown below. Here, in the braided shield, it was verified how the braiding shield manufacturing property, the characteristics vary depending on the presence or absence of twisting of the wire and the lay length.

[0044] <Production of Samples> As the samples Al to A3 and the samples Bl, B2, shielded electric wires were prepared. In each of the samples, a hollow cylindrical braided shield was disposed around the outer periphery of a member formed by arranging two insulated electric wires in parallel, each of which has a conductor with a conductor cross-sectional area of 95 mm 2 composed of a copper alloy strand. In each of the samples, the constituent material and the braiding structure of the braided shield, and the presence or absence of twisting and the lay length of the wire were as shown in Table 1. In the samples Al to A3, B2 in which the wire was twisted, the wires corresponding to the number of strands were twisted in a bundle at the lay length as described in Table 1. Also, the strands corresponding to the number of cores were all arranged in the same twisting direction to form a braided structure. In the sample Bl, the wires were not twisted, and only a braided structure was formed in a state in which the wires were set in a bundle. In each of the samples, the size of the braided shield was set to an inner diameter of 34.2 mm.

[0045] The braiding density of each of the samples was as follows. Sample Al: 74.6% Sample A2: 96.4% Sample A3: 97.3% Sample Bl: 74.6% (a portion in which wire breaking did not occur) Sample B2: 35.5%

[0046] <Evaluation method> (1) Presence or absence of needle skipping In each test sample, the presence or absence of needle skipping was evaluated by visually observing the surface of the braided shield. In a case where needle skipping was not found in a length region of 300 mm along the length direction of the braided shield, the evaluation was "no needle skipping (A)". On the other hand, in a case where needle skipping was found, the evaluation was "needle skipping (B)".

[0047] (2) Manufacturability In a case where the wire set was braided using a winding machine and a braiding machine to manufacture the braided shield, the manufacturability of the braided shield of each test sample was evaluated based on whether or not wire breakage occurred during formation of the braided shield for a length of 300 mm. In a case where no wire breakage occurred, the evaluation was "high manufacturability (A)", and in a case where wire breakage occurred, the evaluation was "low manufacturability (B)".

[0048] (3) Shielding performance The shielding performance of each shielded electric wire was evaluated by radiation emission evaluation based on the current probe method. Specifically, a current probe was attached to the outer periphery of the braided shield of each shielded electric wire, and an alternating current signal was input to the insulated electric wire surrounded by the braided shield. Then, the amount of noise radiation was measured using the current probe. The difference between the amount of noise radiation measured in a state where the braided shield was not provided and the amount of noise radiation measured in a state where the braided shield was provided was set as the noise blocking amount. In a region of 100 MHz or less, if the noise blocking amount was 20 dB or more, the evaluation was "high shielding performance (A)". On the other hand, in a case where the noise blocking amount was less than 20 dB, the evaluation was "low shielding performance (B)". In addition, regarding the test sample B1, a shielded electric wire capable of evaluating the shielding performance could not be obtained due to wire breakage during manufacture of the braided shield.

[0049] <Evaluation results> In Table 1 below, regarding the test samples A1 to A3 and the test samples B1 and B2, the structure of the braided shield formed is shown together with the results of each evaluation. In terms of the lay pitch, the lay pitch of the wire in the lay wire constituting the braided shield is expressed in terms of both the length in "mm" and the layer core diameter ratio (i.e., a multiple value based on the layer core diameter obtained by subtracting the outer diameter of one wire from the outer diameter of the lay wire).

[0050] [Table 1]

[0051] According to Table 1, in samples A1 to A3, the wires in the braided shielding were stranded, and the twist pitch of the stranded wires was more than 90 times the core diameter. In these samples, no skipping occurred in the braided shielding, and manufacturability was improved. Furthermore, high shielding performance was achieved. On the other hand, in sample B1, where the braided shielding was formed without twisting the wires, skipping occurred, and manufacturability decreased. In sample B2, although the wires were twisted in the braided shielding, the twist pitch was less than 90 times the core diameter. In sample B2, although skipping did not occur and high manufacturability was achieved, the shielding performance was lower.

[0052] Based on the comparison of the above evaluation results, in braided shielding, by forming a braided structure by twisting the wires to create strands, skipped stitches can be suppressed, resulting in highly manufacturable braided shielding. However, to achieve high shielding performance, the twist pitch of the wires in the stranded wires needs to be set to more than 90 times the core diameter. This should be explained as follows: by increasing the twist pitch of the wires to more than 90 times the core diameter, the gaps in the braided structure are filled by the loosely twisted wires, thereby improving the shielding performance.

[0053] This invention is not limited to the above-described embodiments and various changes can be made without departing from the spirit of this invention. Explanation of reference numerals in the attached figures

[0054] 1. Shielded wire 2. Insulated wires 21 conductors 22 Insulation layer 3,3' Braided Shielding 30 wire 31 stranded wire 39 Wire Bundles 40 Sheath The structures that cause skipped needles (A1, A2) D1 First Direction D2 Second Direction

Claims

1. A braided shielding element, which is formed by braiding together multiple strands of wire, wherein, The stranded wire is formed by twisting together multiple wires made of conductive material. The strand pitch of the wires in the stranded wire is more than 90 times the core diameter of the stranded wire.

2. The braided shielding component according to claim 1, wherein, The strand pitch of the wires in the stranded wire is less than 150 times the core diameter of the stranded wire.

3. The braided shielding component according to claim 1, wherein, The strands are braided together with each other on a single-strand basis.

4. A shielded wire, comprising: An insulated wire having a conductor and an insulating layer covering the outer periphery of the conductor; and The braided shielding member according to any one of claims 1 to 3, which covers the outer periphery of the insulated wire.

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