Shielding and wiring harness

Abstract

Provided are a shield without a metal foil and a wire harness provided with such a shield. The shield (1) has a porous resin (10) in which a skeleton (11) made of a resin material forms a three-dimensional network structure, and a metal layer (12) that covers the surface of the skeleton (11) of the porous resin (10). Further, the wire harness has a wire group including at least one communication wire, and the shield (1) that covers at least a part of the surface of the wire group.

Description

Technical Field

[0001] This disclosure relates to shielding components and wiring harnesses. Background Technology

[0002] In communication wires used in fields such as automobiles, sheet-like shielding devices containing metal foil, i.e., continuous metal layers in a planar manner, are sometimes used as shielding devices to reduce noise intrusion and radiation from the outside. Such shielding devices are typically made of metal foil, such as the metal foil shielding device for shielded wires disclosed in Patent Document 1, and are composed of metal foil made of Cu, Al, or alloys containing these metals. Alternatively, shielding devices made by bonding a substrate sheet made of a resin material such as polyethylene terephthalate (PET) to a metal foil can also be used.

[0003] When sheet-like shielding is used for noise shielding of communication cables, as exemplified in Patent Document 1, in addition to arranging the shielding around the outer periphery of the core wire constituting a single communication cable, the following arrangement is also possible: in a wire harness containing multiple wires, the shielding is arranged to cover the outer side of the wire assembly. For example, as disclosed in Patent Document 2, it is known that wire harnesses containing multiple wires are fixed to the surface of a sheet made of resin or non-woven fabric by sewing or welding for purposes such as converging multiple wires in the vertical direction to ensure space-saving in the vertical direction. Patent Document 2 does not describe the assembly of shielding for wire harnesses, but when the multiple wires constituting the wire harness include communication cables, it is desirable to provide noise shielding for those communication cables. Existing technical documents Patent documents

[0004] Patent Document 1: Japanese Patent Application Publication No. 2009-146850 Patent Document 2: Japanese Patent Application Publication No. 2018-196174. Summary of the Invention The problem that the invention aims to solve

[0005] As disclosed in Patent Document 1, when a shielding element with metal foil is placed on a communication wire or harness, the metal foil is constructed as a continuous metal, which makes it difficult to use the shielding element conveniently. For example, the inclusion of metal foil increases the weight of the shielding element; and the need to connect the metal foil to grounding complicates the structure and processing of the wire or harness. It is desirable to develop a shielding element that does not contain metal foil.

[0006] Therefore, the objective of this invention is to provide a shielding element that does not contain metal foil and a wire harness having such a shielding element. Methods for solving problems

[0007] The shielding element disclosed herein comprises: a porous resin, a framework of resin material forming a three-dimensional network structure; and a metal layer covering the surface of the framework of the porous resin.

[0008] In addition, the wire harness disclosed herein has: a wire assembly including at least one communication wire; and a shielding member covering at least a portion of the surface of the wire assembly. Invention Effects

[0009] The shielding component and wire harness disclosed herein are shielding components without metal foil and wire harnesses having such shielding components. Attached Figure Description

[0010] Figure 1 This is a cross-sectional view illustrating the structure of a shielding member according to an embodiment of the present disclosure. Figure 2 It is shown Figure 1 Enlarged view of the part represented by the ellipse in the image. Figure 3 This is a plan view illustrating a wire harness according to an embodiment of the present disclosure, with the constituent components removed in a stepped manner at the ends. Figure 4 These are electron microscope images obtained by actually observing the cross-section of the shielding component. Detailed Implementation

[0011] [Description of embodiments of this disclosure] First, embodiments of this disclosure are listed and described. The shielding components and wiring harnesses involved in the embodiments of this disclosure have the following structures.

[0012] [1] The shielding component disclosed herein comprises: a porous resin, wherein a skeleton made of resin material forms a three-dimensional network structure; and a metal layer covering the surface of the skeleton of the porous resin.

[0013] The aforementioned shielding component, comprising a metal layer, functions as a shield to block electrical noise in components such as communication wires and harnesses. This metal layer is not a continuous planar metal foil, but rather a surface covering a porous resin framework with a three-dimensional network structure, with the metal layer itself also forming a three-dimensional network structure. This shielding component has a structure in which multiple metal layers overlap along the thickness direction, separated by the resin framework or air layers between the frameworks. Within each of these metal layers, electromagnetic waves are attenuated due to multiple reflections and the generation of eddy currents, thereby achieving high noise shielding performance. Because the metal layers in this shielding component are formed as a porous resin framework, their specific gravity is easily reduced compared to shielding components containing metal foil. Furthermore, due to the high noise shielding performance, sufficient noise shielding performance can be maintained even without connecting the shielding component to ground potential, eliminating the need for connection structures required for grounding.

[0014] [2] In the above-mentioned [1] scheme, the porous resin is preferably composed of foamed resin. In the foamed resin, a continuous skeleton forms a highly isotropic three-dimensional network structure. Therefore, by using foamed resin to construct a shielding component, in which a highly isotropic network of interconnected metal layers is formed, high noise shielding performance is exhibited against electromagnetic waves incident in all directions, starting with the thickness direction.

[0015] [3] In the above-mentioned [2] scheme, the porous resin is preferably composed of foamed polyurethane resin. Foamed polyurethane resin can form a three-dimensional network structure with high isotropy and stability. Therefore, particularly high noise shielding performance and structural stability can be obtained in the shielding component.

[0016] [4] In any of the embodiments [1] to [3] above, the metal layer preferably covers more than 50% of the surface area of ​​the porous resin skeleton. Thus, the amount of metal contained in the shielding component can be sufficiently ensured, giving the shielding component particularly high noise shielding performance.

[0017] [5] In any of the embodiments [1] to [4] above, preferably, the metal layer is arranged in two or more layers along the thickness direction of the shielding component. Thus, at various points in the shielding component, multiple metal layers are overlapped with each other separated by a resin skeleton or air layer, and electromagnetic waves are attenuated in these metal layers, thereby achieving particularly high noise shielding performance in the shielding component.

[0018] [6] In any of the embodiments [1] to [5] above, the metal layer preferably has a thickness of 3 μm or more. Thus, electromagnetic wave attenuation is effectively generated in the metal layer, thereby achieving high noise shielding performance in the shielding component.

[0019] [7] The wire harness disclosed herein has: a wire assembly comprising at least one communication wire; and a shielding element as described in any one of [1] to [6] above, covering at least a portion of the surface of the wire assembly.

[0020] As described above, the shielding member disclosed herein has a structure in which a surface of a porous resin skeleton with a three-dimensional network structure is covered by a metal layer, thereby achieving high noise shielding performance without the need for a continuous metal foil. By using this shielding member to cover a wire assembly to form a wire harness, high noise shielding performance is achieved for the communication wires included in the wire assembly. Even when the wire assembly includes multiple communication wires, noise shielding can be implemented for all of these communication wires simultaneously. Since the porous resin, formed into a sheet or the like, functions as a matrix in the shielding member, the shielding member is highly easy to operate when covering the wire assembly, and the structure of the wire assembly covered by the shielding member can be stably maintained.

[0021] [8] In the above-described [7] embodiment, preferably, the wire harness further comprises a substrate, each wire constituting the wire group is fixed to the substrate, and the shielding member is fixed to the substrate covering the surface of the wire group. In this case, the wire harness has a structure in which each wire constituting the wire group is fixed to the substrate and the surface of the wire group is covered by the shielding member, thereby achieving high space-saving performance as a whole. In addition, when the wire group includes multiple communication wires, noise shielding can be easily implemented for all of these multiple communication wires together.

[0022] [9] In the embodiments of [7] or [8] above, preferably, the wire harness does not have a grounding wire that connects the metal layer of the shielding member to the ground potential. As described above, the shielding member of this disclosure has high noise shielding performance, and can maintain high noise shielding performance even without connecting the metal layer to the ground potential. By omitting the connection to the ground potential, the overall structure of the wire harness can be simplified, and the components and processing steps necessary for connecting to the ground potential can be eliminated.

[0023] [Details of the embodiments disclosed herein] Hereinafter, with the aid of accompanying drawings, a shielding member and a wiring harness according to embodiments of the present disclosure will be described in detail. As an example of a component including the shielding member according to embodiments of the present disclosure, a wiring harness according to embodiments of the present disclosure is provided.

[0024] <Shielding components> First, the shielding component 1 according to one embodiment of the present disclosure will be described. Figure 1 , Figure 2 The schematic diagram shows the cross-sectional state of the shielding member 1 according to one embodiment of the present disclosure. Figure 1 Showing a wide range of states, Figure 2 Enlarged to show Figure 1 The part enclosed by the ellipse in the middle.

[0025] The shielding member 1 according to this embodiment has a porous resin 10 and a metal layer 12. In the porous resin 10, a framework 11 made of resin material forms a three-dimensional network structure. That is, the framework 11 made of resin material forms a network and extends three-dimensionally, and an air layer A is formed between the framework 11 as a space (bubble) containing air.

[0026] The porous resin 10 is not specifically limited to any type, as long as it has a three-dimensional network structure, that is, a structure in three dimensions comprising a framework 11 made of resin material and an air layer A surrounded by the framework 11. Examples of porous resins 10 include foamed resins and resin nonwoven fabrics. Foamed resins are formed by containing air bubbles in a three-dimensionally connected network structure of resin material. On the other hand, resin nonwoven fabrics are formed by aggregating many discontinuous resin fibers, with air contained between the resin fibers. Among these, a foamed resin is particularly preferred for the porous resin 10. Figure 1 , Figure 2 It is also hypothetically represented as foaming resin.

[0027] Figure 1 , Figure 2 The framework 11 of the porous resin 10 is schematically shown as a continuous hexagonal structure, but the specific structure of the framework 11 is not particularly limited. However, as... Figure 4 The electron microscope image shown is a cross-sectional image of the shielding component actually formed using foamed resin. The actual skeleton 11 also has a structure that is similar to a continuous hexagon or a polygon similar to it.

[0028] The type of resin constituting the porous resin 10 is not particularly limited, and examples include polyethylene resins such as polyethylene terephthalate (PET), chlorine resins such as polyvinyl chloride (PVC), polyolefin resins such as polyethylene (PE) and polypropylene (PP), melamine resins, polyimide resins, and polyurethane resins. When the porous resin 10 is a foamed resin, it is preferable to form the porous resin 10 from polyethylene resins or polyurethane resins. In particular, foamed polyurethane resins are preferred because of their excellent foaming properties, and therefore are preferred in terms of easily forming a highly isotropic and stable three-dimensional network structure. In addition to organic polymers, the resin material constituting the skeleton of the porous resin 10 may also appropriately contain additives. In the porous resin 10, the thickness of the skeleton 11, that is, along the thickness direction of the entire shielding member 1, is the thickness of each skeleton 11 disposed in each part (…). Figure 2 In the process, the thickness of the upper skeleton a and the lower skeleton b is not particularly limited, but preferably 10 μm or more and 100 μm or less is exemplified. Furthermore, preferably, the pore size in the skeleton 11 is 100 μm or more and 800 μm or less, and the porosity is 90% or more and 98% or less. The porous resin 10 functions as a matrix defining the overall shape of the shielding member 1, and the overall shape of the porous resin 10 can be arbitrarily set according to the intended use of the shielding member 1. In cases such as when the shielding member 1 is used in a wire harness (described later), if the porous resin 10 is configured as a sheet, high convenience can be obtained when covering the component to be shielded with the shielding member 1.

[0029] In shielding component 1, the metal layer 12 is configured as a layer that covers the metal on the surface of the skeleton 11 constituting the porous resin 10. That is, the metal layer 12 is formed on the outer peripheral surface of the mesh skeleton 11 of the porous resin 10, corresponding to the edge surrounding the air layer A, covering at least a portion of that outer peripheral surface. The metal layer 12 may be formed only at a local location on the outer peripheral surface of the skeleton 11 of the porous resin 10, but... Figure 1 As shown, the most preferred method is to form the metal layer 12 over the entire area of ​​the outer periphery of the skeleton 11, except for the areas where the metal layer 12 is unavoidably not formed.

[0030] The type of metal constituting the metal layer 12 is not particularly limited. Preferred examples of the type of metal constituting the metal layer 12 include Ni, Cu, Al, Fe, and alloys of these metals. From the perspective of high noise shielding performance and ease of forming the metal layer 12, it is preferable to form the metal layer 12 with Ni or Ni-based alloys, or Cu or Cu-based alloys. The metal layer 12 is preferably composed of a single layer of metal, but it can also be composed of layers of multiple metals stacked together. The metal layer 12 can directly cover the surface of the framework 11 of the porous resin 10, but other types of layers can also be formed between the surface of the metal layer 12 and the framework 11, primarily using a conductive layer composed of conductive carbon or the like. In addition, the shielding member 1 preferably does not have other types of layers such as metal foil or resin film as part of the outer side of the structure described above after the metal layer 12 covers the surface of the framework 11 of the porous resin 10.

[0031] In the shielding component 1 of this embodiment, a metal layer 12 is formed on the surface of the skeleton 11 of the porous resin 10, such as... Figure 2 As shown in the enlarged view, multiple metal layers 12 are stacked in a state where they are separated by a framework 11 made of dielectric or an air layer A. Figure 2 In the area shown, of the two skeletons 11 represented by the two layers, the two metal layers 12 (c, d) covering the top and bottom of the upper skeleton 11 (a) and the two metal layers 12 (e, f) covering the top and bottom of the lower skeleton 11 (b) overlap along the thickness direction. That is, in Figure 2 In the region shown, an overlapping structure is formed from top to bottom in the following order: air layer A → metal layer 12 → skeleton 11 → metal layer 12 → air layer A → metal layer 12 → skeleton 11 → metal layer 12 → air layer A. These overlapping metal layers 12, located at different positions in the thickness direction, are integrally connected to each other via regions extending in the thickness direction within the skeleton 11 coated with porous resin 10, and are also electrically continuous. That is, the network structure of the metal layers 12 has three-dimensional conductivity in all directions, including the planar direction and the thickness direction of the shielding member 1.

[0032] The shielding member 1 according to this embodiment exhibits noise shielding properties by including a metal layer 12. That is, when the shielding member 1 covers a component such as a wire, it functions as follows: by attenuating electromagnetic waves that penetrate the component from the outside, it suppresses the generation of noise in the component; and by attenuating electromagnetic waves radiated from the component to the outside, it suppresses the radiated electromagnetic waves from becoming a source of noise externally. The attenuation of electromagnetic waves occurs along with multiple reflections of electromagnetic waves and the generation of eddy currents in the metal layer 12. Here, as explained above, the shielding member 1 has a structure in which multiple metal layers 12 are overlapped by a framework 11 made of resin material or an air layer A, so that the attenuation of electromagnetic waves associated with multiple reflections and the generation of eddy currents can occur in each of these overlapping metal layers 12. Therefore, electromagnetic waves are significantly attenuated along the thickness direction of the shielding member 1, and the shielding member 1 as a whole can efficiently suppress the transmission of electromagnetic waves, achieving high noise shielding performance.

[0033] Thus, the shielding member 1 according to this embodiment, having a structure in which the surface of the skeleton 11 covered with a metal layer 12 is a porous resin 10, can exhibit high noise shielding performance even without a metal continuous body such as a metal foil that is uniformly continuous in both the planar and thickness directions. Conversely, as described above, the multiple metal layers 12, each separated by a dielectric skeleton 11 or an air layer A, contribute to the attenuation of electromagnetic waves caused by multiple reflections and eddy currents, thereby achieving higher noise shielding performance compared to the case of using a metal foil. Therefore, to achieve the desired noise shielding performance, the total amount of metal used in constructing the shielding member 1 can be reduced compared to the case of using a metal foil. Besides using a porous resin 10 with a specific gravity less than that of the metal layer 12 as a matrix to construct the shielding member 1, the shielding member 1 can be constructed with a small amount of metal, making it easy to reduce the specific gravity in the shielding member 1 according to this embodiment. Furthermore, since it does not possess a metal continuous body such as a metal foil, the shielding member 1 has high flexibility. Furthermore, even when using the same amount of metal as in the case of using metal foil to construct the shielding element 1, the surface area of ​​the metal layer 12 is increased due to the use of porous resin 10 as the matrix. The overall thickness of the shielding element 1 can also be increased. These increases in surface area and thickness also contribute to improving the noise shielding performance of the shielding element 1.

[0034] Furthermore, the shielding member 1 according to this embodiment exhibits excellent noise shielding performance, thus maintaining a high level of noise shielding performance even without connecting the shielding member 1 to the ground potential. By not connecting the shielding member 1 to the ground, the components and processing steps required for grounding connections can be eliminated, reducing component and processing costs. Conventionally, when a shielding member with a metal foil is placed on components such as wires and harnesses, a grounding wire is installed on the metal foil via a terminal or other connecting component, and this grounding wire is connected to the ground potential. However, this not only incurs costs for the grounding wire and connecting components, but also requires labor during installation, and the use of sharp components poses safety concerns. In the shielding member 1 according to this embodiment, these factors are eliminated by omitting the grounding connection. Even when a grounding connection is made, the structure of the connecting components and its installation process can be simplified.

[0035] In the shielding member 1 of this embodiment, the thickness of the metal layer 12 and the area of ​​the porous resin 10 covered by the metal layer 12 are not particularly limited. However, the thickness of the metal layer 12 covering each part of the skeleton 11 of the porous resin 10 is not particularly limited. Figure 2 In the shielding element 1, the thicknesses of the metal layers c, d, e, and f formed on the surfaces of the upper skeleton a and the lower skeleton b are preferably 3 μm or more, more preferably 5 μm or more and 10 μm or more. This allows for particularly high noise shielding performance. The upper limit of the thickness of the metal layer 12 is not specifically set, but from the perspective of avoiding excessive metal usage and improving the flexibility of the shielding element 1, it is preferably 30 μm or less. The thickness of the metal layer 12 can be evaluated by observing a cross-section of the shielding element 1 using an electron microscope and averaging the thickness of the metal layer 12 formed in each part of the observed image. When averaging, it is not necessary to consider the areas on the surface of the porous resin 10 skeleton 11 where no metal layer 12 is formed, i.e., the areas where the thickness of the metal layer 12 is zero. Furthermore, when the shielding element 1 is formed in a sheet shape, the overall thickness of the shielding element 1 is not particularly limited, but for example, from the perspective of balancing high noise shielding performance and flexibility, a range of 100 μm or more and 2000 μm or less can be used.

[0036] The area of ​​the porous resin 10 covered by the metal layer 12 can be defined using the metal layer area ratio. Here, the metal layer area ratio refers to the proportion of the area covered by the metal layer 12 to the surface area of ​​the skeleton 11 constituting the porous resin 10. In the shielding member 1 according to this embodiment, the metal layer area ratio is preferably 50% or more, more preferably 60% or more, or 70% or more. Thus, the shielding member 1 contains a sufficient amount of metal, thereby exhibiting particularly high noise shielding performance. A larger metal layer area ratio is preferred, and no upper limit is specifically specified. The metal layer area ratio is calculated as follows: in the observation image obtained by observing the cross-section of the shielding member 1 with an electron microscope, the total length (skeleton length) of the skeleton 11 of the porous resin 10 connected in a mesh is measured, and the total length (coverage length) of the area covered by the metal layer 12 in the skeleton 11 is measured, and the ratio of the coverage length to the skeleton length is calculated. If the area ratio of the metal layer is less than 100%, a portion of the surface of the skeleton 11 of the porous resin 10 will have areas not covered by the metal layer 12. However, from the perspective of preventing electromagnetic wave leakage, it is preferable that, except in unavoidable locations, areas where the metal layer 12 is not formed at any position along the thickness direction of the shielding member 1 are not formed at any position in the in-plane direction. That is, preferably, the metal layer 12 is formed at a certain position in the thickness direction within the entire in-plane region of the shielding member 1.

[0037] As described above, in the shielding member 1 of this embodiment, multiple metal layers 12 overlap with the skeleton 11 or air layer A in between, thereby improving noise shielding performance; however, from the perspective of fully obtaining this effect, the number of metal layers 12 arranged in such an overlapping manner along the thickness direction of the shielding member 1 is preferably two or more, and more preferably four or more, or eight or more. As explained above, Figure 2 In the area shown, the number of metal layers 12 is four. While no upper limit is specifically set for the number of metal layers 12, it is preferable to control it to 16 layers or less from the perspective of avoiding excessive use of metal and improving the flexibility of the shielding component 1. The number of metal layers 12 is determined as follows: in the observation image obtained by observing the cross-section of the shielding component 1 with an electron microscope, the number of overlapping metal layers 12 in the thickness direction is counted, and this number is averaged across all parts in the surface direction. The number of skeleton 11 and air layer A is not specifically specified, but in order to effectively utilize electromagnetic wave attenuation based on multiple reflections, skeleton 11 must have two or more layers, and air layer A must have three or more layers (including air layers existing on the outer side of the shielding component's overall thickness direction). Furthermore, when counting the number of air layers A, air layers existing on the outer side of the shielding component's overall thickness direction are also included in the count.

[0038] In the shielding member 1 of this embodiment, the metal layer 12 contributes to noise shielding, while the porous resin 10 does not directly participate in noise shielding. However, the porous resin 10 functions as the matrix of the shielding member 1 as a whole, improving the stability of the overall shape maintenance of the shielding member 1 and the ease of operation. Furthermore, in components containing the shielding member 1, such as wire harnesses, which will be described later, it helps to stably maintain the structure in which the shielding member 1 is disposed. In addition, as described above, the porous resin 10 stably maintains the fine structure of the multiple metal layers 12 overlapping with the skeleton 11 or air layer A. From this perspective, the shielding member 1 of this embodiment tends to exhibit higher noise shielding performance compared to a metal porous body that forms a three-dimensional network structure solely from metal.

[0039] As described above, the porous resin 10 can be a resin nonwoven fabric or a foamed resin, but a foamed resin is preferred. The reason is as follows: the resin material of the foamed resin branches in a short period and forms a three-dimensional, continuous network structure. Therefore, the metal layer 12 formed on the surface of the resin skeleton 11 also constitutes a network structure that is highly isotropically connected in all directions, including the planar direction and the thickness direction, exhibiting high conductivity in all directions. Thus, regardless of the incident direction of the electromagnetic wave, the metal layer 12 can provide high noise shielding performance. In contrast, the resin nonwoven fabric only contains linear fibers, and sometimes the connection of the three-dimensional skeleton 11 is not sufficiently achieved. In the case of sheet-like resin nonwoven fabric, the connection of the skeleton 11 is stronger in the in-plane direction, while the connection of the skeleton 11 in the thickness direction tends to weaken. That is, the isotropy of the resin skeleton 11 is lower, and the three-dimensional isotropy of the metal layer 12 formed on the surface of the skeleton 11 is also lower, making the conductivity in the thickness direction lower than that in the planar direction. Therefore, noise shielding performance will also exhibit anisotropy, and it is sometimes difficult to obtain high shielding performance for electromagnetic waves that pass through in the thickness direction.

[0040] The shielding member 1 according to this embodiment can be manufactured by forming a metal layer 12 on the surface of the framework 11 of the porous resin 10. For example, the metal layer 12 can be formed on the surface of the framework 11 of the porous resin 10 by plating. Plating can be performed by electrolytic plating or by chemical plating, but from the perspective of manufacturing efficiency, electrolytic plating is preferred. In this case, before forming the metal layer 12, a conductive layer containing a conductive material such as conductive carbon can be formed on the surface of the framework 11 of the porous resin 10 by coating, impregnation, etc., and then electrolytic plating can be performed.

[0041] The application of the shielding member 1 in this embodiment is not particularly limited, and it can be used to cover various components and devices that require noise shielding. As a preferred application, it can be used in signal transmission components such as communication wires and wire harnesses. When used in communication wires, the sheet-like shielding member 1 can be configured to surround the outer periphery of the core wire containing one or more insulated wires that carries signal transmission. Regarding its use in wire harnesses, a detailed description will be given below. When using the shielding member 1 of this embodiment in various applications, since the shielding member 1 of this embodiment can achieve high noise shielding performance when used alone, it is preferable to use it as a noise shielding component alone, without the need to use it in conjunction with other types of noise shielding bodies such as those with metal foil or metal filament braids. In addition, the shielding member 1 can also be used by connecting it to the ground potential, but as explained above, the shielding member 1 can maintain high noise shielding performance even if it is not connected to the ground potential, so it is preferable to use it without connecting it to the ground potential.

[0042] <Wire Harness> Next, as an example of a component assembled with the shielding member 1 described above, a wiring harness according to an embodiment of the present disclosure will be described. Figure 3 A plan view of a wire harness 5 according to one embodiment of the present disclosure is shown.

[0043] One embodiment of this disclosure relates to a wire harness 5 having a wire assembly 2 comprising at least one communication wire, and a shielding member 1, as described in this disclosure, covering at least a portion of the surface of the wire assembly 2. The arrangement of the wires in the wire assembly 2 and the manner in which the shielding member 1 covers the wire assembly 2 are not particularly limited; for example, the shielding member 1 can be arranged to cover the entire outer periphery of the wire assembly 2 after multiple wires are bundled together. However, here, as a preferred embodiment of the wire harness 5 structure, [the following is a more detailed description of the preferred embodiment]. Figure 3 The method shown is to cover the surface of the wire group 2, in which multiple wires are arranged side by side, with the shield 1.

[0044] Figure 3 The wire harness 5 shown has a wire assembly 2, a shielding member 1 according to the embodiments of this disclosure, and further has a substrate 3. Figure 3 As shown, at the end of the wire harness 5, the shield 1 and the insulating covering layer 21b of the insulating wire 21 constituting the wire assembly 2 are removed in a stepped manner.

[0045] The wire group 2 constituting the wire harness 5 includes at least one communication wire 20. The wire group 2 may consist solely of the communication wire 20, or it may include other types of wires in addition to the communication wire 20; however, it is preferable that the wire group 2 includes multiple communication wires 20, and even more preferably, all the wires constituting the wire group 2 are communication wires 20. The type of communication wire 20 is not particularly limited, but at least one, preferably all, of the communication wires 20 included in the wire group 2 is configured as parallel wires. Parallel wires are communication wires in which a pair of insulated wires 21, with an insulating sheath 21b formed on the outer periphery of the conductor 21a, are arranged axially side-by-side. In the illustrated embodiment, the wire group 2 is constituted by two (two groups) communication wires 20, each of which is configured as a parallel wire. Preferably, each communication wire 20 constituting the wire group 2 does not individually possess noise shielding components such as metal members surrounding the outer periphery of the signal wire (core wire).

[0046] Each wire constituting the wire assembly 2 is fixed to the substrate 3. That is, each wire is aligned horizontally side by side with its axis parallel and is fixed to the surface of the substrate 3. The substrate 3 serves to gather the multiple wires constituting the wire assembly 2 into one and also functions as a buffer member to prevent damage to the individual wires constituting the wire assembly 2 due to physical stimulation such as contact between the wire assembly 2 and components such as metal components constituting the automobile, which are the objects to which the wire harness 5 is installed.

[0047] The substrate 3 is any component that has a surface for attaching and fixing the individual wires of the wire assembly 2, with the communication wire 20 as the first component. There is no particular limitation on its type; however, from the perspective of ensuring the wiring integrity of the wire harness 5, it is preferable to be a sheet-like component with a flexible surface. As the sheet, woven fabric, non-woven fabric, braided fabric, resin sheets, etc., can be used. There is no particular limitation on the method of fixing the wire assembly 2 to the substrate 3; examples include welding, sewing, bonding using adhesives or glues, and fixing using fasteners or other fixing components. Among these, from the perspective of fixing reliability, space saving, and requiring fewer fixing components, welding is preferred to fix the individual wires constituting the wire assembly 2 to the substrate 3. If non-woven fabric is used as the substrate 3, it is easy to firmly and easily fix the individual wires using welding. Furthermore, a high cushioning effect can be obtained. There is no particular limitation on the constituent material of the substrate 3; various resin materials such as polyethylene resin, chlorinated resin, and polyolefin resin are preferred. Multiple materials can also be combined to form the substrate 3.

[0048] In the wire harness 5, the sheet-like shielding member 1 according to the embodiments of this disclosure is arranged to cover the surface of the wire assembly 2, that is, the surface (upper surface) of all the wires constituting the wire assembly 2. Furthermore, the shielding member 1 is located on both sides of the wire assembly 2 in the width direction ( Figure 3The shield 1 is fixed to the substrate 3 in the vertical direction. The shield 1 can be fixed to the substrate 3 by bonding with adhesive tape or adhesive strips, adhesives, or other similar methods. Alternatively, the shield 1 can be fixed by sewing, welding at the exposed position of the porous resin 10, etc. The shield 1 does not need to be distinguished by its front and back sides; when it is arranged to cover the wire assembly 2 in the wire harness 5, the orientation of its face is not specifically specified. In the wire harness 5 according to this embodiment, a grounding wire for connecting the metal layer 12 of the shield 1 to the ground potential and a connecting member for installing the grounding wire to the shield 1 can be provided, but it is preferable to have a structure without these components.

[0049] In the wire harness 5 of this embodiment, multiple wires constituting the wire assembly 2 are arranged side by side and each is fixed to the substrate 3, thereby creating a wire harness with excellent space-saving performance in the height direction (the direction in which the substrate 3, wire assembly 2, and shielding member 1 are stacked). Furthermore, the surface of the wire assembly 2 is covered by the shielding member 1, thereby providing noise shielding for the communication wire 20 included in the wire assembly 2. That is, it shields electromagnetic waves from outside the wire harness 5, suppressing noise generated by the communication wire 20; and it shields electromagnetic waves radiated from the communication wire 20 to the outside, suppressing the radiated electromagnetic waves from becoming noise externally. As described above, the shielding member 1 has a structure in which a metal layer 12 is provided on the surface of the skeleton 11 covered with porous resin 10, thus exhibiting high noise shielding performance. Moreover, its high noise shielding performance can be maintained even if the shielding member 1 is not connected to the ground potential.

[0050] In this embodiment, even though the wire assembly 2 includes multiple communication wires 20, noise shielding can be implemented on all of these multiple communication wires 20 together by a common sheet-like shield 1. Therefore, the increase in the height and width dimensions of the wire harness 5 based on noise shielding is suppressed to the size required only for the sheet with the shield 1. Therefore, compared with the case where noise shielding members are provided separately for each communication wire 20, the space-saving characteristics of the wire harness 5 can be maintained at a higher level. In addition, the labor and cost required for noise shielding can be reduced. In particular, when the communication wires 20 are parallel wires, the space-saving performance in the height direction of the wire harness 5 is higher than that of the case where a pair of insulated wires are twisted together, and fixation to the substrate 3 based on fusion splicing can be easily performed. The cost required for twisting the insulated wires 21 can also be eliminated. On the other hand, parallel wires do not have the twisting structure of twisted wires and are prone to common-mode noise, but the wire harness 5 has the shield 1, thereby reducing the impact of common-mode noise in the parallel wires, and the wire harness 5 can be preferably used for electrical communication in automobiles, etc. The more wires included in the wire group 2, starting with the communication wire 20, the greater the space-saving effect, labor and cost reduction effect brought about by the use of the sheet-like shield 1. For example, when the wire group 2 includes 6 or more (6 groups) or more parallel wires of the communication wire 20, a particularly high effect can be obtained. Example

[0051] Examples are shown below. However, the invention is not limited to these examples. Here, the relationship between the structure of the shielding element and the noise shielding performance in a wire harness is investigated.

[0052] <Sample Preparation> First, shielding components are prepared. Specifically, a sheet-shaped polyurethane foam is impregnated with a conductive coating containing carbon black, forming a conductive layer on the surface of the resin skeleton. Then, a metal layer composed of Ni or Cu is formed on this surface by electroplating. At this time, by varying the pore size and porosity of the polyurethane foam, the type of metal, and the plating conditions during electroplating (metal concentration of the plating solution, current density, temperature, current supply method, etc.), several shielding components with different structures are prepared as samples 1 to 12. In addition, for comparison, shielding components formed by bonding metal foils composed of Cu and Al, respectively, to a PET sheet equivalent to the resin skeleton are prepared as samples 21 and 22.

[0053] Next, use the shielding components prepared above to make the wiring harness. For example... Figure 3As shown, a wire assembly consisting of eight (eight groups) of communication wires, each configured as a parallel wire, is fixed to a substrate. One of the prepared shielding members is then disposed over the surface of these wire assemblies and fixed to the substrate on both sides in the width direction. Here, insulated wires constituting each parallel wire are used, with a conductor cross-sectional area of ​​0.5 mm². 2 The wire has a conductor outer diameter of 0.85 mm and an wire outer diameter of 1.25 mm. A PVC and non-woven fabric laminated together was used as the substrate. No grounding wire connecting the shield to ground potential was included in the wire harness. Correspondingly, a wire harness without shielding was also prepared as sample 23.

[0054] <Evaluation Methods> The structures of the shielding components for samples 1-12 were evaluated. Specifically, each shielding component was cut along its thickness direction, and the cross-section was observed using a scanning electron microscope (SEM). The thickness of the porous resin skeleton, the thickness of the metal layer, the metal layer area ratio, and the number of overlapping layers were evaluated by analyzing the obtained SEM images. The thickness of the skeleton and the metal layer were evaluated as follows: the thickness of the resin skeleton and the thickness of the metal layer formed on the surface of the resin skeleton were measured at each part of the SEM image, and the measured values ​​at each part were averaged. When evaluating the thickness of the metal layer, the areas on the surface of the porous resin skeleton where no metal layer has formed were not considered; only the areas where a metal layer has formed were averaged. Regarding the metal layer area ratio, the total length of the porous resin skeleton (skeleton length) and the total length of the area covered by the metal layer in the skeleton (coverage length) were measured in the SEM image, and the metal layer area ratio was calculated as the ratio of the coverage length to the skeleton length. To determine the number of layers, the number of overlapping air layers, skeleton layers, and metal layers in the thickness direction is counted in the SEM image, and the number of each layer obtained in the surface direction is averaged. Regarding air layers, air layers existing on the outer side of the overall shielding structure in the thickness direction are also included in the in-body count.

[0055] Furthermore, the noise shielding performance based on the shielding components was evaluated for the wire harnesses constructed using various shielding components. The evaluation was conducted by measuring radiated emissions using the Antenna Irradiation Method (ALSE method) conforming to the International Special Committee on Radio Interference (CISPR) standard CISPR 25. Specifically, the aforementioned wire harness was prepared as a sample with a section of 1.2 m in length containing 8 (8 groups) of communication wires arranged as parallel wires. At each end of this section, a 5.4 m section was formed, consisting of a pair of insulated wires that constitute each communication wire. The sample was placed in an anechoic chamber, and a rod antenna was positioned 1.0 m laterally offset from the center of the section consisting of parallel wires. An electrical signal with a frequency of 0.53–1.8 MHz was input to each communication wire constituting the wire harness, and the noise radiation was measured using the rod antenna. It was found that the section containing the insulated wires provided almost no contribution to noise radiation.

[0056] The noise radiation level was determined using the peak values ​​of measurements taken from eight (eight groups) of communication wires. Specifically, the maximum value among the peak values ​​in the 0.53–1.8 MHz range was recorded as the noise radiation level. Lower noise radiation levels indicate higher noise shielding performance. Noise shielding performance was considered low (B) when the noise radiation level exceeded the limit of 56 dBμV / m corresponding to Level 3 of the CISPR 25 MW band (0.53–1.8 MHz). Conversely, noise shielding performance was considered high (A) when the noise radiation level was below 56 dBμV / m; and exceptionally high (A+) when the noise radiation level was below the limit of 48 dBμV / m corresponding to Level 4 of the CISPR 25.

[0057] <Experimental Results> Figure 4 As a representative example, a cross-sectional SEM image of sample 1 is shown. Furthermore, Table 1 below shows the shielding structure obtained from SEM image analysis for samples 1-12, and presents the noise radiation levels and noise shielding performance evaluation results measured for samples 1-12 and 21-23. Regarding the thickness of the porous resin skeleton constituting the shielding, it is 50 μm in all samples 1-12. Moreover, the overall thickness of the sheet-like shielding is 800 μm in all samples 1-12.

[0058]

[0059] according to Figure 4 The SEM images confirm the shape of the porous resin skeleton that forms the network structure. Furthermore, the gray lines in the images indicate the areas where the metal layer is formed, showing that the metal layer forms along the porous resin skeleton. The metal layer also reflects the network structure of the porous resin, thus constituting a three-dimensional network structure.

[0060] According to Table 1, the noise radiation in sample 23, where the wire harness lacks shielding, exceeds 56 dBμV / m. In contrast, samples 1 to 12, equipped with shielding components having a metal layer on the surface of the porous resin skeleton, all exhibit noise radiation levels below 56 dBμV / m, achieving high noise shielding performance. This confirms that by covering multiple communication wires configured as parallel wires with shielding components having a metal layer on the surface of the porous resin skeleton for noise shielding, sufficiently high noise shielding performance can be achieved in each communication wire.

[0061] Here, comparing samples 1-12, which use shielding elements with a metal layer on the surface of a porous resin framework, with samples 21 and 22, which use shielding elements with a continuous metal foil, the former achieves noise shielding performance equal to or higher than the latter. Specifically, in samples 11 and 21, Cu is used as the metal, and the total thickness of the Cu layer is 8 μm (2 μm × 4 layers) in sample 11 and 9 μm in sample 21, which are close, but sample 11 is slightly thinner. Comparing the noise radiation levels in samples 11 and 21, sample 11 exhibits lower noise radiation and higher shielding performance. In other words, compared to shielding elements with a metal foil, using a shielding element with a metal layer structure formed on the surface of a porous resin framework achieves higher noise shielding performance with the same or less metal content.

[0062] Here, among the samples 1-12 using shielding components with a metal layer on the surface of a porous resin skeleton, Ni was used as the metal constituting the metal layer (samples 1-6) and Cu was used (samples 7-12). However, regardless of the metal used, as long as the thickness, area ratio, and number of metal layers were similar, the same level of noise radiation could be obtained. For example, the relationship between sample 2 and sample 8 is as follows. From these results, it can be seen that high noise shielding performance can be obtained by using either Ni or Cu as the metal layer.

[0063] In samples 3 and 5, the metal layer area ratio and the number of layers are basically the same, but the thickness of the metal layers differs. Comparing the noise shielding performance of these samples, sample 3, with its thicker metal layer, exhibits lower noise radiation. Similarly, samples 2 and 6 have similar metal layer thicknesses, but their metal layer area ratios and the number of metal layers differ. Samples 8 and 12 show the same relationship. Comparing the noise shielding performance among these groups, samples 2 and 8, with larger metal layer area ratios and more metal layers, exhibit lower noise radiation compared to samples 6 and 12, with smaller metal layer area ratios and more metal layers. In particular, samples 1–4 and 7–10, with metal layer thicknesses of 3 μm or more, metal layer area ratios of 50% or more, and more than two metal layers, achieve noise radiation suppression to below 48 dBμV / m, obtaining a particularly high noise shielding performance rated A+.

[0064] 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

[0065] 1 Shielding component 10 Porous Resins 11 (Porous resin) skeleton 12 metal layers 2 wire sets 20. Communication wires 21 Insulated wires 21a Conductor 21b Insulation Covering 3. Substrate 5. Wiring harness A. Air layer The layers of skeletons a and b c to f are the various metal layers.

Claims

1. A shielding component, comprising: Porous resins, with a three-dimensional network structure formed by a framework of resin materials; and A metal layer that covers the surface of the skeleton of the porous resin.

2. The shielding component according to claim 1, wherein, The porous resin is composed of foaming resin.

3. The shielding component according to claim 2, wherein, The porous resin is composed of foamed polyurethane resin.

4. The shielding component according to claim 1, wherein, The metal layer covers more than 50% of the surface area of ​​the porous resin skeleton.

5. The shielding component according to claim 1, wherein, Along the thickness direction of the shielding component, the metal layer is provided in two or more layers.

6. The shielding component according to claim 1, wherein, The metal layer has a thickness of 3 μm or more.

7. A wire harness, comprising: A wire bundle containing at least one communication wire; and A shielding element according to any one of claims 1 to 6 that covers at least a portion of the surface of the wire assembly.

8. The wire harness according to claim 7, wherein, The wire harness also has a substrate. Each wire constituting the wire assembly is fixed to the substrate. The shielding element is fixed to the substrate, covering the surface of the wire assembly.

9. The wire harness according to claim 7, wherein, The wiring harness does not have a grounding wire that connects the metal layer of the shield to a ground potential.

Images