Wire harness

Abstract

Provided is a wire harness in which an electric wire group including a plurality of electric wires for communication is fixed to a shared base material, wherein noise shielding is applied to each electric wire for communication with a simple structure, while enabling space saving.　A wire harness 1 comprises: an electric wire group 2 that includes a plurality of electric wires 20 for communication; a ground wire 3 that is provided with a conductor wire 31 and an insulating coating 32 which coats the conductor wire 31, and that can be connected to a ground potential; a base material 4; and a sheet-shaped shielding material 5 that is provided with a metal layer 51. Each electric wire constituting the electric wire group 2 is fixed to the base material 4. The shielding material 5 covers the surface of the electric wire group 2 and is fixed to the base material 4. The conductor wire 31 of the ground wire 3 is electrically connected to the metal layer 51 of the shielding material 5.

Description

Wire harness

[0001] The present disclosure relates to a wire harness.

[0002] In some cases, a wire harness is constructed by fixing electric wires to the surface of a sheet material made of a resin sheet or a nonwoven fabric in order to assemble a plurality of electric wires while maintaining a space-saving effect in the vertical direction. For example, Patent Document 1 discloses a form in which a wire harness in which electric wires are fixed to a sheet material by sewing or welding is arranged along a plate-like member included in an interior member of a vehicle. Among various electric wires, it is also considered that communication electric wires may be fixed to a sheet material and incorporated into a wire harness.

[0003] Japanese Patent Application Laid-Open No. 2018-196174

[0004] When a communication wire is included in a wire harness in which a plurality of electric wires are fixed to a sheet material as described in Patent Document 1, it is desirable to provide noise shielding for the communication wire. In particular, when the communication wire is configured as a parallel wire in which a pair of insulated electric wires are arranged side by side, noise shielding becomes important because the influence of common noise tends to be large, unlike in the case of a twisted wire in which a pair of insulated electric wires are twisted together.

[0005] When a wire harness includes multiple communication wires, providing noise shielding for each individual communication wire increases the labor and cost required for noise shielding. Furthermore, even if space savings are achieved by arranging the wires in a way that is ingenious, such as by fixing them to a common sheet material, providing noise shielding to multiple communication wires means that the overall volume of the shielding material becomes large, which may prevent the space-saving effect from being fully utilized.

[0006] Therefore, an object of the present invention is to provide a wire harness in which a group of electric wires including a plurality of electric wires for communication are fixed to a common substrate, and which has a simple structure, ensures space saving, and provides noise shielding for each electric wire for communication.

[0007] The wire harness of the present disclosure includes an electric wire group including a plurality of communication electric wires, a ground wire that includes conductor wires and an insulating coating that covers the conductor wires and can be connected to a ground potential, a substrate, and a sheet-like shielding material that includes a metal layer, wherein each electric wire constituting the electric wire group is fixed to the substrate, the shielding material covers a surface of the electric wire group and is fixed to the substrate, and the conductor wire of the ground wire is electrically connected to the metal layer of the shielding material.

[0008] The wire harness according to the present disclosure is a wire harness in which a group of electric wires including a plurality of communication electric wires is fixed to a common substrate, and is a wire harness that has a simple structure, ensures space saving, and provides noise shielding for each communication electric wire.

[0009] Fig. 1 is a plan view showing a wire harness according to an embodiment of the present disclosure. Components are gradually removed from the end portion to show the wire harness. Fig. 2 is a cross-sectional view showing the structure near the end portion of the wire harness. Fig. 3 is a plan view schematically showing the connection state of the wire harness. Fig. 4 is a cross-sectional view showing the structure of a shielding material constituting the wire harness. Figs. 5A and 5B are views showing a wire harness according to a modified embodiment in which the shielding material is divided into multiple pieces. Fig. 5A is a plan view schematically showing the wire harness and its connection state, and Fig. 5B is a cross-sectional view showing the joint between the divided shielding materials.

[0010] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described. A wire harness according to an embodiment of the present disclosure has the following configuration.

[0011] [1] A wire harness according to the present disclosure includes a wire group including a plurality of communication wires, a ground wire including conductor wires and an insulating coating covering the conductor wires and connectable to a ground potential, a substrate, and a sheet-like shielding material including a metal layer, wherein each wire constituting the wire group is fixed to the substrate, the shielding material covers a surface of the wire group and is fixed to the substrate, and the conductor wire of the ground wire is electrically connected to the metal layer of the shielding material.

[0012] In the above-described wire harness, a group of electric wires including a plurality of communication electric wires is fixed to a substrate and then covered with a shielding material. This shielding material serves as noise shielding for each of the communication electric wires included in the group of electric wires. Current generated in the metal layer of the shielding material by noise shielding is conducted to ground potential by the ground wire. By covering the group of electric wires with a common shielding material and fixing the shielding material to the substrate, noise shielding can be performed collectively for the plurality of communication electric wires included in the group of electric wires, thereby enabling noise shielding for each communication electric wire with a simple structure. Furthermore, the increase in the height and width dimensions of the wire harness due to noise shielding is limited to the dimensions required to cover the group of electric wires with the sheet-like shielding material, ensuring high space-saving properties.

[0013] [2] In the aspect [1] above, the communication electric wire may be configured as a parallel electric wire in which a pair of insulated electric wires are arranged with their axes aligned. Compared to a twisted electric wire in which a pair of insulated electric wires are twisted together, a parallel electric wire can be used to configure this type of wire harness in which a group of electric wires is fixed to a substrate because the electric wire height can be kept small, the parallel electric wire can be easily fixed to a substrate, and the cost required for twisting can be eliminated. On the other hand, while a parallel electric wire is more likely to generate common-mode noise than a twisted electric wire, covering the parallel electric wire with a shielding material can effectively reduce the common-mode noise.

[0014] [3] In the above aspect [1] or [2], the shielding material may further have a resin film, and the metal layer may be provided on a surface of the resin film. By having the resin film in the shielding material, the mechanical strength and handleability of the shielding material are improved.

[0015] [4] In the aspect [3] above, the shielding material may further include an adhesive layer made of an adhesive on the surface of the resin film opposite the metal layer, and the shielding material may cover the group of electric wires with the surface on which the adhesive layer is provided facing inward, and may be fixed to the substrate and the group of electric wires by the adhesive layer. In this case, the adhesive layer may be used to easily fix the shielding material to the substrate without using a fixing member or applying a separate adhesive. Furthermore, the shielding material may be fixed in close contact with the group of electric wires, thereby enhancing the noise shielding effect for the group of electric wires.

[0016] [5] In any one of the above aspects [1] to [4], the ground wire may be provided only in a partial region along the axial direction of the group of electric wires. As long as the ground wire is electrically connected to the metal layer of the shielding material at at least one point, it can fulfill the role of directing the current generated during noise shielding to ground potential. Therefore, even if the wire harness has a long group of electric wires or shielding material, it is sufficient to provide the ground wire only in a partial region along the axial direction of the group of electric wires. By configuring the ground wire to be short, the space-saving and lightweight nature of the wire harness can be improved, and material costs can be kept low.

[0017] [6] In the above aspect [5], the ground wire may be provided in a region that includes at least one end of the shielding material along the axial direction of the group of electric wires. This allows the ground wire to be short, while providing high convenience in attaching the ground wire to the shielding material and connecting it to a ground potential.

[0018] [7] In any one of the above aspects [1] to [6], the ground wire may be disposed outside the space in which the shielding material covers the group of electric wires. This simplifies the structure of the wire harness, saves space, and makes it easier to attach the ground wire to the shielding material.

[0019] [8] In any one of the above aspects [1] to [7], the electrical connection between the conductor wire of the ground line and the metal layer of the shielding material may be formed by piercing a piercing terminal connected to the ground line into the metal layer. This makes it possible to easily form an electrical connection having low contact resistance between the conductor wire of the ground line and the metal layer of the shielding material and to maintain it stably.

[0020] [9] In any one of the above aspects [1] to [8], the thickness of the metal layer may be 10 μm or more, so that the shielding material exhibits high noise shielding performance.

[0021]

[10] In any one of the above aspects [1] to [9], the contact resistance at the electrical connection between the conductor wire of the ground line and the metal layer of the shielding material may be 60 Ω or less. This makes it easier for current generated by noise shielding to flow to ground potential via the electrical connection between the conductor wire of the ground line and the metal layer of the shielding material, thereby enabling effective noise shielding by the shielding material.

[0022]

[11] In any one of the above aspects [1] to

[10] , the shielding material may cover 60% or more of the surface area of ​​the group of electric wires, excluding an area necessary for connecting the electric wires constituting the group of electric wires to an external member. In this way, the shielding material can effectively provide noise shielding for the communication electric wires included in the group of electric wires.

[0023]

[12] In any one of the above aspects [1] to

[11] , the shielding material may be divided into a plurality of segmented shielding materials that cover the surface of the group of electric wires, and at least some of the segmented shielding materials may be ground-connecting shielding materials whose metal layers are electrically connected to the conductor wires of the ground line, and the proportion of the area of ​​the ground-connecting shielding materials to the total area of ​​the plurality of segmented shielding materials may be 35% or more. By dividing the shielding material into a plurality of segmented shielding materials, even if the group of electric wires and the substrate have various shapes, the segmented shielding materials can be combined to cover the surface of the group of electric wires with just the right amount of shielding material, making it easier to provide noise shielding. If the proportion of the total area of ​​the ground-connecting shielding materials is 35% or more, current generated by noise shielding can be sufficiently passed to ground potential via the ground line, thereby achieving high noise shielding performance.

[0024]

[13] In any one of the above aspects [1] to

[12] , the group of electric wires may include six or more communication electric wires (six sets). When the group of electric wires includes six or more communication electric wires (six sets), if noise shielding is applied individually to each communication electric wire, space saving is reduced and the labor and cost required for noise shielding increase. However, by collectively shielding all communication electric wires with a common sheet-like shielding material, these problems can be alleviated.

[0025] [Details of Embodiments of the Present Disclosure] Wire harnesses according to embodiments of the present disclosure will be described in detail below with reference to the drawings. In this specification, terms such as "parallel" that indicate the shape or arrangement of members include not only a strict geometrical concept but also errors within a generally acceptable range for wire harnesses, such as approximately ±15% in length or approximately ±15° in angle.

[0026] <Overall Configuration of Wire Harness> First, the overall structure of a wire harness according to an embodiment of the present disclosure will be described. Fig. 1 shows a plan view of a wire harness 1 according to an embodiment of the present disclosure, and Fig. 2 shows a cross section of the wire harness 1 taken perpendicular to the axial direction near an end portion. In this specification, directions such as the up-down direction and the lateral direction (width direction) correspond to the directions shown in Fig. 2.

[0027] The wire harness 1 according to this embodiment includes an electric wire group 2, ground wires 3, a substrate 4, and a shielding material 5. In Fig. 1, the insulating coatings of the electric wires constituting the electric wire group 2 and the shielding material 5 are shown removed in stages at the end.

[0028] The electric wire group 2 constituting the wire harness 1 includes a plurality of communication electric wires 20. The type of the communication electric wires 20 is not particularly limited, but at least one, and preferably all, of the plurality of communication electric wires 20 included in the electric wire group 2 are preferably configured as parallel electric wires. A parallel electric wire is a communication electric wire in which a pair of insulated electric wires 21, each having an insulating coating 21b formed on the outer periphery of a conductor 21a, are arranged with their axes aligned horizontally. The number of communication electric wires 20 included in the electric wire group 2 is not particularly limited, but is preferably six or more (six pairs). The electric wire group 2 may be composed of only a plurality of communication electric wires 20, or may include other types of electric wires in addition to the communication electric wires 20. In the illustrated embodiment, the electric wire group 2 is composed of two (two pairs) of communication electric wires 20, and each of the two communication electric wires 20 is configured as a parallel electric wire. It is preferable that each of the communication electric wires 20 constituting the electric wire group 2 does not have a noise shielding member such as a metal member surrounding the outer periphery of the signal wire.

[0029] The ground wire 3 is an electric wire that can be connected to an external ground potential. In the wire harness 1 according to the present embodiment, the ground wire 3 is configured as an insulated electric wire including a conductor wire 31 and an insulating coating 32. The detailed configuration of the ground wire 3 is not particularly limited, and a conventional insulated electric wire can be used as the ground wire 3. For example, an insulated electric wire may be used in which the conductor wire 31 is configured as a stranded wire in which a plurality of wires made of a metal such as copper or a copper alloy, or aluminum or an aluminum alloy, are twisted together, and the insulating coating 32 made of a resin composition containing a chlorine-based resin such as polyvinyl chloride (PVC) or a polyolefin-based resin such as polypropylene (PP) is formed around the conductor wire 31.

[0030] Each electric wire constituting the electric wire group 2 is fixed to the base material 4. That is, each electric wire is arranged horizontally with its axial direction aligned parallel to one another, and each is fixed to the surface of the base material 4. The base material 4 not only serves to bundle the plurality of electric wires constituting the electric wire group 2 together, but also functions as a buffer member that suppresses damage to each electric wire constituting the electric wire group 2 when the electric wire group 2 is subjected to physical stimuli such as contact with components on which the wire harness 1 is installed, such as metal components that constitute an automobile.

[0031] The base material 4 is not particularly limited in type as long as it has a surface on which the communication wires 20 and other electric wires constituting the electric wire group 2 can be aligned and fixed. However, from the viewpoint of ensuring the routing of the wire harness 1, it is preferable that the base material 4 be a sheet body, i.e., a flexible planar member. Examples of the sheet body that can be used include fabrics such as woven fabrics, nonwoven fabrics, and knitted fabrics, and resin sheets. The method of fixing the electric wire group 2 to the base material 4 is not particularly limited, and examples include fusion bonding, sewing, bonding using an adhesive or pressure-sensitive adhesive, and fixing using a fixing member such as a fastener. Among these, from the viewpoints of secure fixation, space-saving, and the number of parts required for fixation, it is preferable to fix the electric wires constituting the electric wire group 2 to the base material 4 by fusion bonding. Using a nonwoven fabric as the base material 4 makes it easy to fix the electric wires firmly and easily using fusion bonding. Furthermore, a high cushioning effect is obtained. The material of the base material 4 is not particularly limited, and various resin materials can be suitably used, such as polyethylene resins such as polyethylene terephthalate (PET), chlorine-based resins such as PVC, and polyolefin resins such as PP. The base material 4 may be made of a combination of multiple materials.

[0032] The shielding material 5 is configured as a sheet body including a metal layer 51. The configuration of the shielding material 5 will be described in detail later, but the shielding material 5 is arranged in the wire harness 1 so as to cover the surface of the electric wire group 2, i.e., the surface (top surface) of the assembly of all the electric wires that make up the electric wire group 2. The shielding material 5 is fixed to the base material 4 on both sides in the width direction of the electric wire group 2. In the illustrated embodiment, the shielding material 5 has the metal layer 51, the resin film 52, and the adhesive layer 53 in this order, and the shielding material 5 is arranged with the surface of the adhesive layer 53 facing inward, i.e., toward where the electric wire group 2 is arranged.

[0033] In the wire harness 1, the conductor wires 31 of the ground wires 3 are electrically connected by an electrical connection portion 6 to a metal layer 51 of a shielding material 5 that covers the electric wire group 2. The position of the ground wires 3 relative to the electric wire group 2 and the shielding material 5 and the structure of the electrical connection portion 6 between the metal layer 51 of the shielding material 5 and the conductor wires 31 of the ground wires 3 are not particularly limited, but in the illustrated embodiment, the ground wires 3 are provided outside the shielding material 5, that is, outside the space in which the shielding material 5 covers the electric wire group 2. The ground wires 3 are provided along the axial direction of the electric wire group 2 (the left-right direction in FIG. 1 ) so as to overlap a partial region of the end of the shielding material 5 and extend to the outside of the wire harness 1. Note that FIG. 2 shows a cross section of the region of the entire length of the wire harness 1 where the ground wires 3 are provided near the end.

[0034] At the end of the ground wire 3, the insulating coating 32 is removed to expose the conductor wire 31, and an electrical connection 6 is formed at the exposed location of the conductor wire 31. At the electrical connection 6, the exposed conductor wire 31 of the ground wire 3 directly contacts the metal layer 51 of the shielding material 5 or indirectly contacts the metal layer 51 via a conductive member, thereby establishing and maintaining an electrical connection between the conductor wire 31 and the metal layer 51. The electrical connection 6 may be configured or mechanism-based to establish or maintain the electrical connection between the conductor wire 31 and the metal layer 51, and examples of such methods include terminal connection, welding, soldering, and fixing with conductive or insulating adhesive tape. The embodiment shown in FIG. 1 assumes a configuration in which a connection terminal, particularly a piercing terminal, is used for the electrical connection 6. The piercing terminal has a claw-shaped piercing portion at its tip, and the piercing portion of the piercing terminal to which the ground wire 3 is connected is pierced into the metal layer 51 of the shielding material 5 to electrically connect the ground wire 3 and the metal layer 51.

[0035] 3 is a schematic plan view showing the connection state of the wire harness 1 according to this embodiment. The ground wire 3 is connected to an external ground potential (GND) at an end opposite the electrical connection portion 6, extending outside the wire harness 1. In the wire harness 1, the ground wire 3 may be installed and connected to a ground potential at at least one end along the axial direction of the electric wire group 2. However, as shown in the figure, it is preferable to install the ground wire 3 at both ends and connect each ground wire 3 to a common ground potential. Although not shown, each electric wire constituting the electric wire group 2 is connected to a predetermined device or electric component, such as a communication device, in the automobile via an electrical connection member such as a connection terminal, as appropriate.

[0036] In the wire harness 1 according to the present embodiment, the plurality of electric wires constituting the electric wire group 2 are arranged side by side and fixed to the base material 4, resulting in a wire harness 1 that is highly space-saving in the height direction. Furthermore, the surface of the electric wire group 2 is covered with the shielding material 5 having the metal layer 51, so that the shielding material 5 serves as a noise shield for the plurality of communication electric wires 20 included in the electric wire group 2. That is, the shielding material 5 shields electromagnetic waves originating from outside the wire harness 1, suppressing noise generation in the communication electric wires 20, and also shields electromagnetic waves emitted from the communication electric wires 20 to the outside, suppressing the emitted electromagnetic waves from causing noise outside. Since the conductor wires 31 of the ground wires 3 are electrically connected to the metal layer 51 constituting the shielding material 5, if the ground wires 3 are connected to an external ground potential (GND), a current generated by noise shielding flows to the ground potential via the ground wires 3, thereby demonstrating high noise shielding performance.

[0037] In this embodiment, noise shielding can be collectively performed on the multiple communication electric wires 20 included in the electric wire group 2 using the common sheet-like shielding material 5. Therefore, the increase in the height and width dimensions of the wire harness 1 due to noise shielding is limited to the dimensions necessary to arrange the sheet of shielding material 5. Therefore, compared to a case in which a noise shielding member is individually provided for each communication electric wire 20, the space-saving nature of the wire harness 1 can be maintained at a high level. Furthermore, the labor and cost required for noise shielding can be reduced. In particular, when the communication electric wires 20 are parallel electric wires, the wire harness 1 is more space-saving in the height direction than when a twisted electric wire is formed by twisting a pair of insulated electric wires 21 together, and fixing to the substrate 4 by fusion or the like can be easily performed. The cost required for twisting the insulated electric wires 21 can also be reduced. On the other hand, parallel electric wires are prone to common noise because they do not have a twisted structure like twisted electric wires. However, the presence of the shielding material 5 in the wire harness 1 reduces the influence of common noise in the parallel electric wires, making the wire harness 1 suitable for use in electrical communications in automobiles, etc. The greater the number of electric wires included in the electric wire group 2, including the communication electric wires 20, the greater the space-saving effect and labor- and cost-reducing effect achieved by using the sheet-like shielding material 5. For example, particularly effective results can be achieved when the electric wire group 2 includes six or more communication electric wires 20, such as parallel electric wires (six sets), or even eight or more communication electric wires (eight sets). When the wire harness 1 includes the communication electric wires 20 and other types of electric wires, the other types of electric wires may be disposed inside or outside the space covered by the shielding material 5. However, disposing the other types of electric wires outside the space can enhance the noise shielding effect for the communication electric wires 20 covered by the shielding material 5.

[0038] Providing a ground wire 3 in the wire harness 1 and dissipating eddy currents generated in the metal layer 51 of the shielding material 5 due to noise shielding to ground potential via the ground wire 3 is important for maintaining high noise shielding performance over the long term. The ground wire 3 fulfills its function as long as it can be electrically connected to the metal layer 51 of the shielding material 5 at at least one location. Therefore, even if the wire harness 1 has a long structure, it is sufficient to provide the ground wire 3 only in a partial region along the axial direction of the electric wire group 2. Keeping the length of the ground wire 3 overlapping the shielding material 5 short contributes to space-saving and lightweighting of the wire harness 1. Furthermore, the material costs required for manufacturing the wire harness 1 can be reduced. In particular, providing the ground wire 3 in a region including at least one end of the shielding material 5 along the axial direction of the electric wire group 2, as in the configurations shown in FIGS. 1 and 3 , provides high convenience in forming the electrical connection 6 and connecting to the ground potential. When providing the ground wires 3 at both end portions, as shown in the figure, it is preferable to separate the ground wires 3 on both sides from each other and to provide a region in the middle along the axial direction of the electric wire group 2 where no ground wires 3 are arranged. The ground wires 3 may be provided inside the space in which the electric wire group 2 is covered by the shielding material 5, but providing them on the outside as shown in the figure is preferable in terms of the simplicity and space-saving properties of the structure of the wire harness 1, and the convenience of forming the electrical connection portion 6.

[0039] <Configuration of Shielding Material> Next, a description will be given of details of the shielding material 5 that constitutes the wire harness 1. As described above, in the wire harness 1, the shielding material 5 covers the electric wire group 2 and plays a role of noise shielding for the communication electric wires 20 included in the electric wire group 2.

[0040] The details of the configuration of the shielding material 5 are not particularly limited as long as it has the metal layer 51. However, as shown in the cross-sectional view of Fig. 4, it is preferable that the shielding material 5 includes a resin film 52 in addition to the metal layer 51, with the metal layer 51 provided on the surface of the resin film 52. By including the resin film 52 in the shielding material 5, the mechanical strength of the shielding material 5 is increased and the handleability of the shielding material 5 is also improved compared to when the shielding material 5 is configured from an independent metal foil. The metal layer 51 may be formed by adhering it to one surface of the resin film 52 by vapor deposition, plating, adhesion, or the like.

[0041] Furthermore, the shielding material 5 preferably has an adhesive layer 53 on the surface that faces inward when covering the electric wire group 2. The adhesive layer 53 is configured as a layer of adhesive, i.e., a pressure-sensitive adhesive. When the shielding material 5 has a resin film 52, as shown in FIG. 4 , the adhesive layer 53 is provided on the surface of the resin film 52 opposite to the surface on which the metal layer 51 is provided, and the shielding material 5 may be incorporated into the wire harness 1 with the surface on which the adhesive layer 53 is provided facing inward and the surface on which the metal layer 51 is provided facing outward. When the shielding material 5 is configured with an independent metal layer 51 (metal foil) and does not have a resin film 52, the adhesive layer 53 may be provided directly on the surface of the metal layer 51. By using the adhesive layer 53, the shielding material 5 covering the electric wire group 2 can be easily fixed to the substrate 4. Furthermore, by using the adhesive layer 53 to closely adhere and fix the shielding material 5 to the electric wire group 2, high noise shielding performance for the electric wire group 2 can be achieved. The area on the surface of the shielding material 5 where the adhesive layer 53 is provided is not particularly limited, and the adhesive layer 53 may be provided over the entire surface of the shielding material 5, or the adhesive layer 53 may be provided only in a partial area of ​​the surface, such as by arranging the adhesive in a predetermined pattern.

[0042] In the shielding material 5, the specific constituent materials of the metal layer 51, resin film 52, and adhesive layer 53 are not particularly limited. Examples of metals that can be used for the metal layer 51 include copper, copper alloys, aluminum, aluminum alloys, silver, silver alloys, and materials in which the surfaces of these metals are plated with tin, nickel, silver, gold, or the like. Among these, aluminum or aluminum alloys are preferred. Suitable constituent materials for the resin film 52 include various resin materials, such as polyethylene-based resins such as polyethylene terephthalate (PET), chlorine-based resins such as polyvinyl chloride (PVC), and polyolefin-based resins such as polypropylene (PP). Suitable adhesives for the adhesive layer 53 include acrylic-based adhesives, silicone-based adhesives, and urethane-based adhesives.

[0043] The thickness of each layer of the metal layer 51, resin film 52, and adhesive layer 53 in the shielding material 5 is not particularly limited. The thickness of the metal layer 51 is preferably 10 μm or more, and even 15 μm or more. This makes it easier to obtain high noise shielding performance in the shielding material 5. On the other hand, the thickness of the metal layer 51 is preferably limited to 1 mm or less, and even 100 μm or less. This reduces the rigidity of the shielding material 5 and ensures high flexibility in the shielding material 5, which is advantageous for covering the surface of the wire group 2 and bending the wire harness 1. Suitable examples of the thickness of the resin film 52 include a range of 10 μm or more, even 15 μm or more, and 1 mm or less. Suitable examples of the thickness of the adhesive layer 53 include a range of 20 μm or more, even 50 μm or more, and 1 mm or less.

[0044] As described above, the metal layer 51 of the shielding material 5 is electrically connected to the conductor wire 31 of the ground line 3 at the electrical connection portion 6. Preferably, the contact resistance between the metal layer 51 and the conductor wire 31 at the electrical connection portion 6 is kept to 60 Ω or less, more preferably 10 Ω or less, or even 2 Ω or less. By keeping the contact resistance at the electrical connection portion 6 low, current generated in the metal layer 51 during noise shielding is more likely to flow to the ground potential through the conductor wire 31, thereby achieving high noise shielding performance. The lower the contact resistance, the more preferable it is, and no lower limit is specifically set. The contact resistance depends on the type of electrical connection portion 6, the specific structure of the electrical connection portion 6, the connection strength, and the like. When using terminal connection using a piercing terminal or the like, welding, soldering, or fixation with conductive adhesive tape, as exemplified above, the contact resistance can be easily kept low. In particular, when using a piercing terminal, the electrical connection between the metal layer 51 and the conductor wire 31 can be easily formed and the formed electrical connection can be maintained with excellent stability. On the other hand, if fixing is performed using insulating adhesive tape, the contact resistance tends to be high.

[0045] In the wire harness 1, the coverage of the shielding material 5 on the surface of the electric wire group 2 is preferably 60% or more, and even 80% or more. Here, the coverage of the shielding material 5 refers to the proportion of the area of ​​the surface of the electric wire group 2 that is covered by the shielding material 5, and refers to the proportion of the area of ​​the area covered by the shielding material 5 to the area occupied by the electric wire group 2 when the wire harness 1 is viewed from above. However, the coverage is evaluated excluding areas necessary for connecting each electric wire constituting the electric wire group 2 to an external member. For example, the coverage may be evaluated excluding areas 80 mm long from both ends of each electric wire of the electric wire group 2. When the coverage of the shielding material 5 is 60% or more, and even 90% or more, the noise shielding effect of the metal layer 51 can be sufficiently exerted on the communication electric wires 20 included in the electric wire group 2. There is no upper limit to the coverage, and 100% is most preferred.

[0046] 1 to 3 and described above, the entire shielding material 5 provided in the wire harness 1 is integrally continuous. However, the present invention is not limited to such an embodiment, and the shielding material 5 may be provided in a form divided into a plurality of parts.

[0047] 5A is a schematic plan view showing a wire harness 1' according to a modified embodiment of the present disclosure, in which the shielding material is divided into a plurality of divided shielding materials 5'. In the wire harness 1' according to this modified embodiment, a plurality of divided shielding materials 5' cover the surface of the group of electric wires 2, rather than a single continuous shielding material. In the illustrated embodiment, three divided shielding materials 5' are installed. The configuration of each divided shielding material 5', including the stacking configuration, is the same as the configuration of the shielding material 5 described in detail above, and only the area is different.

[0048] The arrangement pattern of the divided shielding materials 5' is not particularly limited, and examples include a form in which a plurality of divided shielding materials 5' are provided in the width direction of the electric wire group 2 in which a plurality of electric wires are arranged, or a form in which a plurality of divided shielding materials 5' are provided along the axial direction of the electric wire group 2 as shown in Fig. 5A. In particular, when the width of the area to be covered with the shielding material changes along the axial direction of the electric wire group 2 or when the electric wire group 2 branches at an intermediate location, by arranging a plurality of divided shielding materials 5' of different widths side by side along the axial direction of the electric wire group 2, each area can be covered with the divided shielding materials 5' without excess or deficiency.

[0049] When multiple divided shielding materials 5' are provided, from the viewpoint of increasing noise shielding efficiency, it is preferable to leave no gaps between adjacent divided shielding materials 5' and to have the ends of two divided shielding materials 5' overlap each other. However, when the divided shielding materials 5' have a resin film 52 and an adhesive layer 53, in the area where the two divided shielding materials 5' overlap, as shown in Figure 5B, the resin film 52 and the adhesive layer 53 are interposed between the metal layer 51 of one divided shielding material 5' and the metal layer 51 of the other divided shielding material 5'. In this case, because the resin film 52 and the adhesive layer 53 are normally insulating, no conduction occurs between the metal layers 51 of two adjacent divided shielding materials 5'. As shown in Figure 5A, even if ground wires 3 are attached to the divided shielding materials 5' (a, c) at both ends of multiple divided shielding materials 5' arranged side by side and connected to ground potential via the ground wires 3, the divided shielding materials 5' other than the divided shielding materials 5' at both ends (ground-connected shielding materials), namely the central divided shielding material 5' (b) in the illustrated form, will remain unconnected to ground potential.

[0050] Even if some of the divided shielding materials 5' are not connected to ground potential, the wire harness 1' can still achieve a certain level of noise shielding performance. However, keeping the proportion of divided shielding materials 5' not connected to ground potential low will result in higher noise shielding performance. For example, if the divided shielding materials 5' whose metal layers 51 are electrically connected to the conductor wires 31 of the ground wires 3 are used as ground-connected shielding materials, and the proportion of the area of ​​the ground-connected shielding materials to the total area of ​​all divided shielding materials 5' (ground connection area ratio) is set to 35% or more, or even 50% or more, good noise shielding performance can be achieved. A higher ground connection area ratio is preferable, with 100% being most preferable. The ground connection area ratio can vary depending on the division and arrangement pattern of the divided shielding materials 5' and the structure of the areas adjacent to the divided shielding materials 5'.

[0051] <Other Embodiments> In the embodiment described above, the ground wire 3 is configured as an insulated wire, and the conductor wire 31 of the ground wire 3 is electrically connected to the metal layer 51 of the shielding material 5 (or divided shielding material 5′; the same applies below) at the electrical connection portion 6, thereby connecting the metal layer 51 to the ground potential via the ground wire 3. However, the method for ensuring electrical contact between the ground wire 3 and the metal layer 51 of the shielding material 5 is not limited to this embodiment. For example, the ground wire 3 may be configured as a drain wire made of a bare conductor wire 31, and the drain wire may be brought into contact with the metal layer 51 of the shielding material 5 directly or via a conductive material such as a conductive adhesive, thereby establishing electrical contact between the drain wire and the metal layer 51. In this case, it is preferable to arrange the drain wire parallel to the group of electric wires 2, and to cover the surface of the assembly of the group of electric wires 2 and the drain wire with the shielding material 5 with the surface of the metal layer 51 facing inward. The adhesive layer 53 may be formed partially on the surface of the metal layer 51 or may be formed using a conductive adhesive.

[0052] Furthermore, although the above description has mainly focused on a configuration in which the adhesive layer 53 is provided on the shielding material 5, the adhesive layer 53 may be omitted. In that case, however, it becomes necessary to fix the shielding material 5 to the base material 4 by applying an adhesive (including a pressure-sensitive adhesive) or using a fixing member such as a pin at the locations where the shielding material 5 contacts the base material 4 on both sides in the width direction of the electric wire group 2. In this case, it will require labor and cost to apply the adhesive and install the fixing member.

[0053] It is also possible to provide noise shielding by sandwiching the group of electric wires 2, which includes a plurality of horizontally arranged electric wires, from both above and below using a sheet-like shielding material 5 having a metal layer 51 used in the wire harness 1 (1') according to the embodiment of the present disclosure, or by surrounding the outer periphery of the group of electric wires 2 with a similar shielding material 5. However, in these configurations, two metal layers 51 are arranged vertically, and anti-phase eddy currents may be generated between the two metal layers 51. Anti-phase eddy currents interfere with noise shielding by the metal layers 51. Therefore, these configurations are not preferred. For the same reason, a configuration in which metal layers 51 are formed on both sides of a resin film 52 in a single shielding material is also not preferred. As described above, a configuration in which a shielding material 5 having a metal layer 51 formed only on one side of a resin film 52 is arranged only above the group of electric wires 2 is preferred.

[0054] Examples are shown below. However, the present invention is not limited to these examples. Here, the relationship between the configuration of a wire harness and noise shielding performance was investigated.

[0055] <Test Method> As shown in each figure, a group of eight communication wires (eight sets) each configured as parallel wires was fixed to a substrate, the surface of the group of wires was covered, a sheet-like shielding material was placed, and the group was fixed to the substrate on both sides in the width direction. Furthermore, as shown in Figure 3, ground wires were attached near both ends of the shielding material, and an electrical connection was formed between the conductor wire of the ground wire and the metal layer of the shielding material. Here, the insulated wires constituting each parallel wire had a conductor cross-sectional area of ​​0.5 mm ２ The ground wire used was a conductor with a cross-sectional area of ​​0.5 mm, made of stranded aluminum alloy wires. ２ The insulated wire used was an insulated wire with an outer diameter of 0.85 mm, with a PVC layer formed around the conductor wire as an insulating coating. The base material was a PVC laminated nonwoven fabric. The electrical connection between the conductor wire of the ground line and the metal layer of the shielding material was made by terminal connection using a piercing terminal, soldering, or fixing with conductive or insulating adhesive tape, depending on the desired contact resistance.

[0056] As shown in Figure 4, the shielding material used was a PET film as a resin film, with an aluminum layer as a metal layer on one surface and an adhesive layer on the other surface. An acrylic adhesive was used as the adhesive that constituted the adhesive layer. The shielding material was fixed to the substrate, with the adhesive layer facing inward, to cover the group of electric wires.

[0057] As shown in Table 1 below, the thickness of each layer in the shielding material, the contact resistance between the metal layer of the shielding material and the conductor wire of the ground line, the coverage rate of the shielding material in the wire harness, and the ground connection area rate of the divided shielding material were varied for multiple samples. The contact resistance was varied depending on whether the electrical connection between the conductor wire and the metal layer was achieved by terminal connection using piercing terminals, soldering, fixing with conductive adhesive tape, or fixing with insulating adhesive tape. Furthermore, when conductive adhesive tape was used, the contact resistance was finely varied by changing the number of sheets of conductive adhesive tape applied. The coverage rate of the shielding material was adjusted by providing an area at the end of the wire harness that was not covered by the shielding material and changing the length of that area. The coverage rates in Table 1 were evaluated for an area excluding 80 mm long areas from both ends of the wire group. For the ground connection area rate, a single continuous sheet of shielding material was used to obtain a 100% value. On the other hand, when the ground connection area ratio is set to less than 100%, multiple divided shielding materials are arranged in the axial direction of the group of electric wires, and divided shielding materials other than those at both ends are not connected to the ground potential, as shown in Fig. 5A. Furthermore, the area of ​​the divided shielding materials that are not connected to the ground potential is adjusted to change the ground connection area ratio.

[0058] The noise shielding performance of the shielding material was evaluated for each wire harness fabricated as described above. The evaluation was performed by measuring radiated emissions using the antenna irradiation method (ALSE method) in accordance with the CISPR25 standard of the International Special Committee on Radio Interference (CISPR). Specifically, a wire harness was prepared as a sample, with eight (eight pairs) communication wires arranged as parallel wires, each with a length of 1.2 m. At both ends of each section, a 5.4 m section was formed in which a pair of insulated wires constituting each communication wire was twisted together. The sample was placed in an anechoic chamber, and a rod antenna was installed 1.0 m to the side of the center of the parallel wire section. An electrical signal with a frequency of 0.53 to 1.8 MHz was then input to each communication wire constituting the wire harness, and the noise radiation level was measured using the rod antenna. The twisted insulated wire section barely contributed to noise radiation.

[0059] The noise radiation level was measured using peak values ​​from eight (eight sets) of communication cables. In other words, the maximum peak value in the frequency range of 0.53 to 1.8 MHz was recorded as the noise radiation level. The smaller the noise radiation level, the higher the noise shielding performance of the shielding material. When the noise radiation level exceeded 56 dBμV / m, the limit corresponding to Class 3 of the CISPR25 MW band (frequency 0.53 to 1.8 MHz), the noise shielding performance was rated as low (B). On the other hand, when the noise radiation level was 56 dBμV / m or less, the noise shielding performance was rated as high (A). Furthermore, when the noise radiation level was 48 dBμV / m or less, the limit corresponding to Class 4 of CISPR25, the noise shielding performance was rated as particularly high (A+).

[0060] <Test Results> Table 1 below shows the structure of the shielding material, the amount of noise radiation measured for each sample, and the evaluation results of noise shielding performance.

[0061]

[0062] According to Table 1, Sample 25, which does not have a shielding material in the wire harness, has a noise radiation level exceeding 56 dBμV / m. In contrast, Samples 1 to 24, which are equipped with a shielding material having a metal layer, all have noise radiation levels of 56 dBμV / m or less, achieving high noise shielding performance. This confirms that by providing noise shielding by covering multiple communication electric wires, each configured as parallel electric wires, collectively with a sheet-like shielding material, it is possible to achieve sufficiently high noise shielding performance for each communication electric wire.

[0063] Among Samples 1 to 24, the set of Samples 1 to 3 and the set of Samples 7 and 12 each have similar contact resistance, shielding material coverage, and ground connection area ratio, but differ from each other in the thickness of the metal layer. In each set, a tendency is observed for the noise radiation level to decrease as the metal layer thickness increases. Furthermore, Samples 3 to 11 have similar metal layer thicknesses, shielding material coverage, and ground connection area ratios, but differ from each other in the contact resistance between the metal layer of the shielding material and the conductor wire of the ground line. In these samples, a tendency is observed for the noise radiation level to decrease as the contact resistance decreases. Samples 13 to 16 have similar metal layer thicknesses, contact resistance, and ground connection area ratios, but differ from each other in the coverage of the shielding material. In these samples, a tendency is observed for the noise radiation level to decrease as the coverage of the shielding material increases. Samples 4 and 17 to 24 have similar metal layer thicknesses, contact resistance, and shielding material coverage, but differ from each other in the ground connection area ratio. In these samples, a tendency is observed for the noise radiation level to decrease as the ground connection area ratio increases.

[0064] In particular, samples 1 to 10, 13 to 15, and 17 to 23, which had a metal layer thickness of 10 μm or more, a contact resistance of 60 Ω or less, a shielding material coverage rate of 60% or more, and a ground connection area rate of 35% or more, suppressed noise radiation to 48 dBμV / m or less, achieving particularly high noise shielding performance rated A+. The adhesive layer and resin film do not contribute to noise shielding by the metal layer, and the thickness of the adhesive layer and the resin film have almost no effect on noise shielding performance. This is also indicated by the fact that the correlations between the metal layer thickness, contact resistance, shielding material coverage rate, and ground connection area rate and the noise radiation amount hold regardless of the differences in the thickness of the adhesive layer and the resin film.

[0065] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the present invention.

[0066] REFERENCE SIGNS LIST 1, 1' Wire harness 2 Group of electric wires 20 Communication electric wire 21 Insulated electric wire 21a Conductor 21b Insulating coating 3 Ground wire 31 Conductor wire 32 Insulating coating 4 Base material 5 Shielding material 5' Divided shielding material 51 Metal layer 52 Resin film 53 Adhesive layer 6 Electrical connection portion

Claims

1. A wire harness comprising: an electric wire group including a plurality of communication electric wires; a ground wire comprising a conductor wire and an insulating coating covering the conductor wire, and connectable to a ground potential; a substrate; and a sheet-like shielding material having a metal layer, wherein each of the electric wires constituting the electric wire group is fixed to the substrate, the shielding material covers a surface of the electric wire group and is fixed to the substrate, and the conductor wire of the ground wire is electrically connected to the metal layer of the shielding material.

2. The wire harness according to claim 1, wherein the communication electric wire is configured as a pair of parallel electric wires insulated with their axes aligned.

3. The wire harness according to claim 1 or 2, wherein the shielding material further has a resin film, and the metal layer is provided on a surface of the resin film.

4. The wire harness according to claim 3, wherein the shielding material further has an adhesive layer made of an adhesive on a surface of the resin film opposite to the surface on which the metal layer is provided, the shielding material covers the group of electric wires with the surface on which the adhesive layer is provided facing inward, and the shielding material is fixed to the substrate and the group of electric wires by the adhesive layer.

5. The wire harness according to claim 1 or 2, wherein the ground wire is provided only in a partial area along the axial direction of the group of electric wires.

6. The wire harness according to claim 5, wherein the ground wire is provided in a region including at least one end of the shielding material along the axial direction of the group of electric wires.

7. The wire harness according to claim 1 or 2, wherein the ground wire is disposed outside a space in which the shielding material covers the group of electric wires.

8. A wire harness as described in claim 1 or 2, wherein an electrical connection between the conductor wire of the ground wire and the metal layer of the shielding material is formed by piercing a piercing terminal to which the ground wire is connected into the metal layer.

9. The wire harness according to claim 1 or 2, wherein the thickness of the metal layer is 10 μm or more.

10. The wire harness according to claim 1 or 2, wherein a contact resistance at an electrical connection between the conductor wire of the ground wire and the metal layer of the shielding material is 60 Ω or less.

11. A wire harness as described in claim 1 or 2, wherein the shielding material covers 60% or more of the surface area of ​​the group of electric wires, excluding an area required for connecting the electric wires constituting the group of electric wires to an external member.

12. A wire harness as described in claim 1 or 2, wherein the shielding material is divided into a plurality of divided shielding materials and covers a surface of the group of electric wires, at least some of the plurality of divided shielding materials are ground-connecting shielding materials having a metal layer electrically connected to the conductor wire of the ground line, and the proportion of the area of ​​the ground-connecting shielding materials to the total area of ​​the plurality of divided shielding materials is 35% or more.

13. The wire harness according to claim 1 or 2, wherein the group of electric wires includes six or more of the communication electric wires.

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