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 and in which noise blocking is applied to each electric wire for communication with a simple structure and while ensuring space saving.　A wire harness 1 has: an electric wire group 2 including a plurality of electric wires 20 for communication; a ground wire 3 that is provided with a conductor wire and can be connected to a ground potential; a base material 4; and a sheet-form shielding material 5 having 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 of the ground wire 3 is in electrical contact with 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 a wire group including a plurality of communication wires, a ground wire having a conductor wire and connectable to a ground potential, a base material, and a sheet-like shielding material having a metal layer, wherein each wire constituting the wire group is fixed to the base material, the shielding material covers a surface of the wire group and is fixed to the base material, and the conductor wire of the ground wire is in electrical contact with 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, in which components are gradually removed from an end portion. Fig. 2 is a cross-sectional view showing the wire harness. Fig. 3 is a plan view schematically showing a connection state of the wire harness. Fig. 4 is a cross-sectional view showing a structure of a shielding material constituting the wire harness. Fig. 5 is a cross-sectional view showing a configuration in which a plurality of wire harnesses are stacked and arranged.

[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 an electric wire group including a plurality of communication electric wires, a ground wire including a conductor wire and connectable to a ground potential, a base material, and a sheet-like shielding material including a metal layer, wherein each electric wire constituting the electric wire group is fixed to the base material, the shielding material covers a surface of the electric wire group and is fixed to the base material, and the conductor wire of the ground wire is in electrical contact with 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 of [1] above, the ground wire may be configured as a drain wire with the conductor wire exposed, and may be covered by the shielding material together with the group of electric wires. The ground wire may be electrically connected to the metal layer of the shielding material directly or via a conductive layer. This allows the drain wire to be simply connected to the shielding material directly or via a conductive layer, and the metal layer of the shielding material to be easily connected to ground potential via the drain wire, thereby achieving high noise shielding performance. An example of the conductive layer is the conductive adhesive layer described below.

[0014] [3] In the aspect [2] above, the shielding material may further have a resin film, the metal layer may be provided on a surface of the resin film, and the surface on which the metal layer is provided may be facing inward to cover the group of electric wires and the drain wire. By having the resin film in the shielding material, the mechanical strength and handleability of the shielding material are improved.

[0015] [4] In the above-mentioned aspects [2] or [3], the shielding material may further have an adhesive layer made of an adhesive on the surface of the metal layer, and the shielding material may be fixed to the substrate, the group of electric wires, and the drain wire by the adhesive layer. In this case, the adhesive layer makes it possible to easily fix the shielding material to the substrate without using a fixing member or applying a separate adhesive. Furthermore, the shielding material can be fixed in close contact with the group of electric wires and the drain wire, thereby enhancing the noise shielding effect for the group of electric wires and maintaining stable contact between the drain wire and the shielding material.

[0016] [5] In the aspect [4] above, the adhesive layer may be insulating, and the metal layer may have an exposed area where the adhesive layer is not formed on the surface at least in a portion covering the drain wire, and the exposed area may be in direct contact with the drain wire, thereby making electrical contact with the drain wire. In this case, it is possible to easily achieve both fixation between the drain wire and the metal layer by the adhesive layer and ensuring electrical contact by contact between the drain wire and the metal layer.

[0017] [6] In the aspect of [5] above, the adhesive layer may be formed in a regular pattern on the surface of the metal layer. In this case, a structure is reliably formed on the surface of the metal layer in which an area where the adhesive layer is formed and an exposed area where the metal layer is exposed without being covered by the adhesive layer coexist, and each area can be used to fix the shielding material to various members (substrate, electric wire group, drain wire) and to establish electrical conduction between the drain wire and the metal layer.

[0018] [7] In the above aspect [6], the pattern may be a stripe pattern, which makes it easier to achieve a good balance between fixing the shielding material to various components and electrical continuity between the drain wire and the metal layer.

[0019] [8] In any one of the above aspects [5] to [7], the area ratio of the region on the surface of the metal layer where the adhesive layer is formed may be 40% or more and 70% or less. In this case, the adhesive strength of the adhesive layer can firmly fix the shielding material to each component, and electrical continuity due to contact between the metal layer and the drain wire can be easily ensured.

[0020] [9] In any one of the above aspects [5] to [8], the thickness of the metal layer may be 15 μm or more. In this case, the shielding material exhibits high noise shielding performance.

[0021]

[10] In any one of the above aspects [5] to [9], the thickness of the adhesive layer may be 20 μm or less. In this case, at the portion where the shielding material covers the drain wire, the difference in height between the portion where the drain wire contacts the adhesive layer and the portion where the drain wire directly contacts the metal layer is kept small. Therefore, the drain wire contacts the metal layer over a large contact area, ensuring electrical continuity between the drain wire and the metal layer and making it easier to achieve high noise shielding performance.

[0022]

[11] Alternatively, in the above aspect [4], the adhesive layer may be electrically conductive. In this case, even if the drain wire does not directly contact the metal layer of the shielding material but contacts it via the adhesive layer, electrical continuity between the metal layer and the drain wire can be ensured. Therefore, even if the adhesive layer is provided over a wide area of ​​the surface of the metal layer, high noise shielding performance can be ensured by the shielding material, making it easier to achieve both strong fixation of the shielding material to various components and high noise shielding performance.

[0023]

[12] In the aspect of

[11] above, the thickness of the metal layer may be 10 μm or more. In this case, the shielding material exhibits high noise shielding performance. Because the adhesive layer is conductive, high noise shielding performance can be obtained even if the metal layer is thin, compared to when an insulating adhesive layer is used.

[0024]

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

[12] , 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.

[0025]

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

[13] , 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 advantageously 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, being covered with a shielding material can effectively reduce the common-mode noise.

[0026]

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

[14] , 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.

[0027]

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

[15] , the wire harness may be stacked in two or more layers. In this case, a large number of electric wires can be densely packed while providing noise shielding. Furthermore, the shielding material constituting each layer of the stacked wire harness contributes to noise shielding, thereby achieving high noise shielding performance. Furthermore, even if some of the shielding materials of the stacked wire harnesses are damaged by external injury or the like, the noise shielding effect can be maintained by the shielding materials of the other wire harnesses.

[0028] [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.

[0029] <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 cut perpendicular to the axial direction. In this specification, directions such as the up-down direction and the lateral direction (width direction) correspond to the directions shown in Fig. 2.

[0030] 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.

[0031] 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.

[0032] The ground wire 3 is an electric wire that includes a conductor wire and 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 a drain wire in which the conductor wire is exposed without being covered with an insulating coating. The configuration of the drain wire is not particularly limited, but a suitable example is a stranded wire in which a plurality of copper or copper alloy wires or wires with tin plating on the outer periphery thereof are twisted together.

[0033] 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 due to physical stimulation such as contact between the electric wire group 2 and a member on which the wire harness 1 is to be installed, such as a metal member (body structural member 9) that constitutes an automobile.

[0034] 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 polyvinyl chloride (PVC), and polyolefin resins such as polypropylene (PP). The base material 4 may be made of a combination of multiple materials.

[0035] In the wire harness 1, the drain wire 3 may be disposed in any positional relationship with respect to the electric wire group 2. For example, as shown in the figure, the electric wires constituting the electric wire group 2 are arranged horizontally and fixed to the base material 4, and the drain wire 3 may be arranged next to these electric wires with its axis parallel to those electric wires. The drain wire 3 may be fixed to the base material 4 like the electric wire group 2, or may be simply placed on the surface of the base material 4 without being fixed. In this configuration, it is possible to particularly improve space saving in the height direction of the wire harness 1. Alternatively, a configuration in which the drain wire 3 is placed on the electric wire group 2 in which the electric wires are arranged horizontally is also suitable. In this configuration, it is easy to ensure a large contact area between the drain wire 3 and the shielding material 5.

[0036] 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 surfaces of the electric wire group 2 and the drain wires 3, i.e., the surface (top surface) of the assembly made up of all the electric wires constituting the electric wire group 2 and the drain wires 3. 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 and the resin film 52, and the shielding material 5 is arranged with the surface of the metal layer 51 facing inward, i.e., toward the side where the assembly of the electric wire group 2 and the drain wires 3 is arranged, and the drain wires 3 are in contact with the metal layer 51.

[0037] Fig. 3 is a schematic plan view showing the connection state of the wire harness 1 according to this embodiment. At least one end of the drain wire 3, preferably both ends as shown, are connected to an external ground potential (GND). Although not shown, each of the electric wires constituting the electric wire group 2 is connected to a predetermined device or electrical component, such as a communication device, in the automobile via an electrical connection member such as a connection terminal as appropriate. When the wire harness 1 is mounted in an automobile, for example, as shown in Fig. 2, the underside of the base material 4 (the surface opposite to the surface to which the electric wire group 2 is fixed) may be placed along the surface of a vehicle body structural member 9, and the base material 4 may be fixed to the vehicle body structural member 9 as appropriate.

[0038] In the wire harness 1 according to this embodiment, the plurality of electric wires constituting the electric wire group 2 are arranged side by side and each is fixed to the base material 4, resulting in a wire harness 1 that is excellent in 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. When the drain wire 3 formed as a bare conductor wire comes into contact with the metal layer 51 constituting the shielding material 5, conduction is established between the drain wire 3 and the metal layer 51. Therefore, if the drain wire 3 is connected to an external ground potential (GND), a current generated by noise shielding flows to the ground potential, thereby exhibiting high noise shielding performance.

[0039] 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.

[0040] <Configuration of Shielding Material> Next, a description will be given of the details of the shielding material 5 that constitutes the wire harness 1. As described above, the shielding material 5 covers the assembly of the electric wire group 2 and the drain wires 3 in the wire harness 1, and plays a role of noise shielding for the communication electric wires 20 included in the electric wire group 2.

[0041] 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 , the shielding material 5 preferably 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 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, bonding, or the like. The thickness of the resin film 52 is not particularly limited, but a suitable example is a thickness in the range of 10 μm or more and 1 mm or less. When the shielding material 5 includes the resin film 52, the shielding material 5 is incorporated into the wire harness 1 with the surface of the resin film 52 facing outward and the surface of the metal layer 51 facing inward, as shown in FIG. 2 .

[0042] The type of metal constituting the metal layer 51 of the shielding material 5 is not particularly limited, and examples thereof include copper, copper alloy, aluminum, aluminum alloy, silver, silver alloy, and materials in which the surface of these metals is plated with tin, nickel, silver, gold, etc. Among these, aluminum or an aluminum alloy is preferably used. When the resin film 52 is used, the material constituting the resin film 52 is also not particularly limited, and various resin materials can be preferably used, such as polyethylene resins such as PET, chlorine-based resins such as PVC, and polyolefin resins such as PP.

[0043] As shown in FIG. 4 , the shielding material 5 preferably has an adhesive layer 53 on the surface of the metal layer 51 (not shown in FIGS. 2 and 5 ). 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, the adhesive layer 53 is provided on the surface of the metal layer 51 opposite the surface that contacts the resin film 52. By using the adhesive layer 53, the shielding material 5 covering the group of electric wires 2 and the drain wire 3 can be easily fixed to the substrate 4. Furthermore, by using the adhesive layer 53 to fix the shielding material 5 in close contact with the group of electric wires 2, high noise shielding performance for the group of electric wires 2 can be achieved. Furthermore, by fixing the drain wire 3 to the shielding material 5 with the adhesive layer 53, the drain wire 3 can be stably maintained in contact with the surface of the shielding material 5.

[0044] Since the shielding material 5 ensures noise shielding performance by electrical contact between the drain wire 3, which is configured as a bare conductor wire, and the metal layer 51, the drain wire 3 must be in contact with the metal layer 51 of the shielding material 5 directly or via a conductive layer, thereby providing electrical continuity between the drain wire 3 and the metal layer 51. As a configuration for achieving this, when the adhesive layer 53 is insulating, as shown in Fig. 4, an example of a configuration in which an exposed area 5a is provided as a region where the adhesive layer 53 is not formed on the surface of the metal layer 51, at least in a portion that covers the drain wire 3. Alternatively, an example of a configuration in which the adhesive layer 53 is configured to be conductive.

[0045] When an insulating adhesive is used, adhesive regions 5b where adhesive layer 53 is formed and exposed regions 5a where adhesive layer 53 is not formed and metal layer 51 is exposed coexist in at least the region of the surface of shielding material 5 that covers drain wire 3. This allows drain wire 3 to be fixed to shielding material 5 in adhesive regions 5b while drain wire 3 is in direct contact with metal layer 51 in exposed regions 5a, ensuring conduction between drain wire 3 and metal layer 51. Conduction between drain wire 3 and metal layer 51 in a state where drain wire 3 is fixed to shielding material 5 can be maintained stably. Suitable insulating adhesives include acrylic adhesives, silicone adhesives, and urethane adhesives.

[0046] When an insulating adhesive is used, the adhesive layer 53 is preferably formed in a regular pattern on the surface of the metal layer 51. This ensures that a structure in which the adhesive regions 5b and the exposed regions 5a are mixed can be formed in various portions of the surface of the metal layer 51. Specific examples of the pattern include continuous patterns such as stripes and lattices, and isolated island patterns such as dots and squares. Among these, a stripe pattern is preferably used from the viewpoint of pattern simplicity. The direction of the stripes is not particularly limited, but it is preferable that the stripes are provided at an angle along the axial direction of the wire harness 1 in order to ensure that both the adhesive regions 5b and the exposed regions 5a appear alternately along the axial direction of the drain wire 3.

[0047] When an insulating adhesive layer 53 is used to provide exposed regions 5a and adhesive regions 5b on the surface of the metal layer 51, it is preferable that the area ratio of the adhesive regions 5b on the surface of the metal layer 51 (the proportion of the area of ​​the surface of the metal layer 51 that is occupied by the adhesive regions 5b) is 40% or more, and even 50% or more. This ensures sufficient adhesion on the surface of the metal layer 51, making it easier to firmly fix the shielding material 5 to the wire group 2, the drain wire 3, and the substrate 4. On the other hand, it is preferable that the area ratio of the adhesive regions 5b is 70% or less, and even 60% or less. This increases the area ratio of the exposed regions 5a where the metal layer 51 can come into contact with the drain wire 3, making it easier to ensure conduction between the metal layer 51 and the drain wire 3 over a large area, and therefore the shielding material 5 has high noise shielding performance. The size of the area continuously occupied by the exposed area 5a and the adhesive area 5b is not particularly limited, but from the viewpoint of ensuring both high noise shielding performance due to conductivity and high adhesiveness in each part of the surface of the shielding material 5, it is preferable that the length of the area continuously occupied by the adhesive area 5b along the axial direction of the drain wire 3 be 1 mm or more and 10 mm or less.

[0048] Furthermore, in a configuration in which an insulating adhesive is used, the thickness of the metal layer 51 is preferably 15 μm or more, and more preferably 20 μm or more. This makes it easier to obtain high noise shielding performance in the shielding material 5. On the other hand, it is preferable to keep the thickness of the metal layer 51 to 1 mm or less, and even more preferably 100 μm or less. This reduces the rigidity of the shielding material 5, and ensures high flexibility in the shielding material 5, which is favorable for covering the surfaces of the electric wire group 2 and the drain wire 3 and for bending the wire harness 1.

[0049] The thickness of the insulating adhesive layer 53 is preferably 1 μm or more, and even more preferably 5 μm or more. This facilitates achieving high adhesiveness. On the other hand, the thickness of the adhesive layer 53 is preferably 20 μm or less, and even more preferably 10 μm or less. This minimizes the height difference between the adhesive region 5 b and the exposed region 5 a on the surface of the metal layer 51. When the drain wire 3 is fixed to the shielding material 5 in the adhesive region 5 b, the metal layer 51 comes into contact with the drain wire 3 over a large contact area in the exposed region 5 a, making it easier to ensure sufficient conductivity. By achieving both high levels of fixation of the drain wire 3 to the shielding material 5 and conductivity between the metal layer 51 and the drain wire 3, the effect of stably maintaining conductivity between the metal layer 51 and the drain wire 3 is enhanced, even in situations where external force is applied.

[0050] On the other hand, if the adhesive layer 53 is configured to be conductive, electrical continuity can be ensured between the metal layer 51 and the drain wire 3 not only at the location where the metal layer 51 and the drain wire 3 are in direct contact with each other, but also at the location where they are in contact with each other via the adhesive layer 53. The conductive adhesive layer 53 can be formed from a material in which a conductive additive such as metal powder is added to an insulating adhesive. Alternatively, the adhesive may be formed using a conductive polymer.

[0051] When the adhesive layer 53 is conductive, electrical continuity can be ensured between the metal layer 51 and the drain wire 3 via the adhesive layer 53. Therefore, compared to when the adhesive layer 53 is insulating, high adhesiveness can be ensured even if the area of ​​the region occupied by the adhesive layer 53 on the surface of the metal layer 51 is increased. In the largest case, the area ratio of the adhesive region 5b on the surface of the metal layer 51 may be 100%. In other words, the adhesive layer 53 can be formed over the entire surface of the metal layer 51. When the adhesive layer 53 is formed over the entire surface, it is not necessary to separately form the adhesive region 5b and the exposed region 5a, and therefore the structure of the shielding material 5 can be simplified.

[0052] Even when the adhesive layer 53 is conductive, the thicker the metal layer 51 constituting the shielding material 5, the better the noise shielding performance. However, since the adhesive layer 53 is conductive, the adhesive layer 53 also exhibits a noise shielding effect. Therefore, compared to when the adhesive layer 53 is insulating, a high noise shielding effect can be obtained even with a smaller thickness of the metal layer 51. For example, the thickness of the metal layer 51 is preferably 10 μm or more, or even 20 μm or more. On the other hand, as in the case where an insulating adhesive layer 53 is provided, the thickness of the metal layer 51 is preferably limited to 1 mm or less, or even 100 μm or less. The thickness of the adhesive layer 53 is not particularly limited, and to obtain sufficient adhesion, it is preferable to set it to, for example, 1 μm or more, or even 5 μm or more. It is also preferable to set it to 100 μm or less. Unlike when the adhesive layer 53 is insulating, it is not necessary to keep the height difference between the adhesive region 5b and the exposed region 5a small, so the thickness of the adhesive layer 53 may be greater than 20 μm.

[0053] Whether the adhesive layer 53 is conductive or insulating, the coverage of the shielding material 5 on the surface of the electric wire group 2 is preferably 60% or more, and even 90% 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 the area necessary for connecting each electric wire constituting the electric wire group 2 to an external member. For example, it may be evaluated by 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.

[0054] <Other Embodiments> In the embodiment described above, the ground wire 3 is configured as a drain wire in which the conductor wire is exposed without being covered with an insulating coating, and the drain wire is in contact with the metal layer 51 of the shielding material 5 facing inward, either directly or via a conductive layer, thereby ensuring electrical contact between the drain wire and the metal layer 51. 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 a coated wire with an insulating coating, rather than a drain wire made of a bare conductor wire. However, in this case, conductivity between the ground wire 3 and the metal layer 51 cannot be ensured by simple contact with the metal layer 51. For example, the conductor wire must be exposed at the end of the ground wire 3, and electrical contact must be established between the conductor wire and the metal layer 51 by terminal connection, welding, soldering, tape fastening, or the like. In this case, it is not necessary to arrange the shielding material 5 with the metal layer 51 facing inward; the shielding material 5 may be arranged with the metal layer 51 facing outward. Furthermore, the ground wire 3 does not need to be arranged inside the area covered by the shielding material 5, running parallel to the group of electric wires 2, but may be arranged outside the shielding material 5. Furthermore, the ground wire 3 does not need to be arranged parallel to the entire group of electric wires 2; it is sufficient to arrange the ground wire 3 in a partial area, such as an end area, along the axial direction of the wire harness 1. However, if the ground wire 3 is configured as an insulated wire, processing is required to form electrical contact with the metal layer 51 of the shielding material 5, which requires labor and cost. Furthermore, it may be difficult to ensure sufficient mechanical strength at the formed electrical contact. The configuration using the drain wire described above is superior in terms of structural simplicity and mechanical strength of the electrical contact point with the metal layer 51 of the shielding material 5.

[0055] Furthermore, although the above description has mainly focused on a configuration in which the adhesive layer 53 is provided on the surface of the metal layer 51 of 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.

[0056] In the embodiment shown in FIG. 1 , a single continuous sheet of shielding material 5 is disposed over the entire area of ​​the wire harness 1. However, the shielding material 5 may be configured to be divided into a plurality of pieces. By dividing the shielding material 5 into a plurality of pieces, noise shielding using the sheet-like shielding material 5 can be applied to wire harnesses 1 of various shapes. For example, the shielding material 5 may be divided into a plurality of pieces in the width direction of the electric wire group 2 in which a plurality of electric wires are arranged, or the shielding material 5 may be divided into a plurality of pieces along the axial direction of the electric wire group 2. In particular, when the width of the area to be covered with the shielding material 5 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 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 shielding material 5 without excess or deficiency. Even if the shielding material 5 is divided into multiple pieces, the conductivity between the multiple shielding materials 5 is also guaranteed as long as each of the divided shielding materials 5 ensures conductivity with the drain wire 3, for example, by contact between the metal layer 51 and the drain wire 3.

[0057] As illustrated in Fig. 5, the wire harness 1 may be arranged by stacking two or more layers. For example, the wire harness 1 as the bottom layer may be attached along the vehicle body structural member 9, and the wire harness 1 as the top layer may be stacked above the bottom wire harness 1 (outside the surface of the resin film 52 of the shielding material 5). The number of layers is not particularly limited, and a group of wire harnesses 1 each having the required number of layers stacked thereon may be appropriately fixed to each other using clips or the like. An adhesive layer may be appropriately provided between the layers to assist in fixing the layers. When stacking multiple wire harnesses 1, the multiple wire harnesses 1 may have the same configuration of the electric wire groups 2 and the same configuration of the shielding material 5, or may have different configurations of the electric wire groups 2 and / or the shielding material 5.

[0058] In this way, by stacking and arranging multiple wire harnesses 1, it is possible to integrate a large number of electric wires, including communication electric wires 20, at high density while ensuring noise shielding properties. In addition, the multiple shielding materials 5 constituting the multiple-layer wire harness 1 function as noise shields for the entire laminate, thereby achieving high noise shielding performance for the laminate. Furthermore, even if the shielding materials 5 constituting some layers of the wire harness 1 are damaged, such as broken, by external injury or the like, and their noise shielding performance is reduced, the shielding materials 5 constituting the other layers of the wire harness 1 make it easy to maintain sufficient noise shielding performance for the entire laminate.

[0059] Furthermore, the stacking arrangement of multiple wire harnesses is not limited to the stacking arrangement of multiple layers of only the wire harness 1 according to the embodiment of the present disclosure, which includes multiple communication wires 20 in the electric wire group 2, as shown in FIG. 5 . Alternatively, one or multiple layers of the wire harness 1 according to the embodiment of the present disclosure may be stacked with other-type electric wires and / or other-type wire harnesses. When using a different-type wire harness that includes other-type electric wires such as power transmission electric wires, it is preferable to place the wire harness 1 according to the embodiment of the present disclosure including the communication wires 20 in the lower layer and the other-type wire harness in the upper layers, such as the top layer. For example, a plurality of other-type electric wires may be arranged and fixed to the surface of the substrate 4, and then incorporated into the laminate as the other-type wire harness. The other-type wire harness does not need to be provided with a shielding material 5.

[0060] Furthermore, among the layers of the wire harness stacked in multiple layers, the wire harness in the top layer may be arranged upside down, that is, with the substrate 4 facing upward. If the wire harness 1 has a shielding material 5 as the top layer, the direction in which the shielding material 5 is arranged faces downward. In this case, the top surface of the entire laminate is covered with the substrate 4, and the effect of the substrate 4 can suppress external damage to the shielding material 5 in the laminate, suppress a decrease in noise shielding performance, and also hide the electric wires from the outside.

[0061] It is also conceivable to provide noise shielding by arranging shielding materials 5 on both the top and bottom of the electric wire group 2, such as by sandwiching the electric wire group 2, which is made up of a plurality of horizontally arranged electric wires, from both the top and bottom with sheet-like shielding materials 5 having a metal layer 51 used in the wire harness 1 according to the embodiment of the present disclosure, or by surrounding the outer periphery of the electric wire group 2 with similar shielding materials 5. In this case, the shielding materials 5 on both the top and bottom of the electric wire group 2 may contribute to noise shielding, resulting in a high noise shielding effect. In such a case, it is also preferable to arrange shielding materials 5 on both the top and bottom of the electric wire group 2. If the vehicle body structural member 9 along which the wire harness 1 is placed is made of metal, the vehicle body structural member 9 can also function as a shielding material arranged below the electric wire group 2. Furthermore, when multiple wire harnesses 1 are stacked as shown in FIG. 5 , the shielding materials 5 constituting the upper and lower wire harnesses 1 can function as shielding materials 5 arranged on both the top and bottom of the electric wire group 2 arranged between them.

[0062] On the other hand, in a configuration in which the shielding material 5 is disposed on both the upper and lower sides of the electric wire group 2, two metal layers 51 are disposed side by side, and anti-phase eddy currents may be generated between the two metal layers 51. Anti-phase eddy currents may interfere with noise shielding by the metal layers 51. In such cases where the influence of anti-phase eddy currents is significant, it is better not to employ a configuration in which the shielding material 5 is disposed on both the upper and lower sides of the electric wire group 2. Whether or not to employ a configuration in which the shielding material 5 is disposed on both the upper and lower sides of the electric wire group 2 can be determined based on the specific configuration and usage environment of the wire harness 1, taking into consideration the magnitude of the noise shielding effect and the influence of anti-phase eddy currents. Note that interference with noise shielding due to anti-phase eddy currents may also occur, by a similar mechanism, in a configuration in which metal layers 51 are formed on both sides of a resin film 52 in a single shielding material. In such a case, as described above, it is particularly preferable to employ a shielding material 5 in which a metal layer 51 is formed on only one side of the resin film 52, and which is disposed only on the upper side of the electric wire group 2.

[0063] 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.

[0064] <Test method> As shown in Figures 1 and 2, a group of eight communication wires (eight sets) each configured as parallel wires was fixed to a substrate, and drain wires were arranged on the substrate alongside the group of wires. Furthermore, the surfaces of the assembly of the group of wires and drain wires were covered with a sheet-like shielding material, which was then fixed to the substrate on both sides in the width direction. Here, the insulated wires constituting each parallel wire were made of a conductor with a cross-sectional area of ​​0.5 mm. ２ The drain wire used was a conductor with a cross-sectional area of ​​0.22 mm, made of twisted tin-plated annealed copper wires. ２ The substrate was a material made by bonding PVC and nonwoven fabric together.

[0065] As shown in Figure 4, the shielding material was made by providing an aluminum layer as a metal layer on one side of a resin film (a 12 μm-thick PET film), and then forming an adhesive layer on the surface of the metal layer. An acrylic adhesive was used as an insulating adhesive, and an acrylic adhesive with Ni powder added was used as a conductive adhesive. The shielding material was fixed to the substrate with the adhesive layer facing inward, covering the group of electric wires and the drain wire.

[0066] As shown in Table 1 below, the shielding material was tested for a number of samples, with different thicknesses, adhesive area ratios, metal layer thicknesses, and shielding material coverage ratios in the wire harnesses. When the adhesive area ratio was less than 100%, the adhesive layer was arranged in stripes on the surface of the metal layer. The angle of the stripes was 45° relative to the axial direction of the wire harness. The adhesive layer stripe width was fixed at 5 mm, and the adhesive area ratio was changed by varying the exposed width of the metal layer. The shielding material coverage ratio was adjusted by providing an area at the terminal of the wire harness that was not covered with the shielding material and varying the length of that area. The coverage ratios in Table 1 are values ​​evaluated for areas excluding 80 mm long areas from both ends of the wire group.

[0067] 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.

[0068] 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+).

[0069] <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.

[0070]

[0071] According to Table 1, Sample 22, 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 21, 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.

[0072] Among samples 1 to 13, in which the shielding material has an insulating adhesive layer, samples 1 to 4 differ from one another in the thickness of the adhesive layer, and a tendency is observed for the noise radiation to decrease as the adhesive layer thickness decreases. Samples 1 and 5 to 8 also differ from one another in the area ratio of the adhesive region, and a tendency is observed for the noise radiation to decrease as the area ratio of the adhesive region decreases. Samples 1 and 9 differ from one another in the thickness of the metal layer, and sample 1, which has a thicker metal layer, has a smaller noise radiation. Samples 1 and 10 to 13 differ from one another in the coverage rate of the shielding material, and a tendency is observed for the noise radiation to decrease as the coverage rate of the shielding material increases. In particular, among the samples in which the shielding material has an insulating adhesive layer, samples 1, 2, 5, 6, and 10 to 12, in which the thickness of the adhesive layer is 20 μm or less, the area ratio of the adhesive region is 70% or less, the thickness of the metal layer is 15 μm or more, and the coverage rate of the shielding material is 60% or more, have noise radiation levels suppressed to 48 dBμV / m or less, and have achieved particularly high noise shielding performance rated as A+.

[0073] In Samples 14 to 21, whose shielding material has a conductive adhesive layer, the adhesive area ratio is 100% or 50%. In the 100% case, the entire surface of the metal layer is covered by the adhesive layer, and all samples exhibit high noise shielding performance. Among these, Samples 14 to 16 differ from one another in the thickness of the metal layer, and a tendency is observed in which the thicker the metal layer, the lower the noise radiation. This tendency is similar to that observed in the case of the insulating adhesive layer described above. However, when comparing the noise radiation levels between Samples 9 and 14, which have the same metal layer thickness and the same shielding material coverage, and between Samples 1 to 4 and 15, whose shielding material has the same shielding material coverage ratio, Samples 14 and 15, whose shielding material has a conductive adhesive layer, exhibit lower noise radiation levels than Samples 9 and 1 to 4, whose shielding material has an insulating adhesive layer. In other words, using a conductive adhesive layer can reduce the thickness of the metal layer required to ensure a desired noise shielding performance. Samples 14 and 17 to 19 differ from one another in the coverage of the shielding material, and as with the case where the adhesive layer is insulating, there is a tendency for the noise radiation amount to decrease as the coverage of the shielding material increases. In particular, among the samples in which the shielding material has a conductive adhesive layer, Samples 14 to 19, in which the metal layer is 10 μm or thick and the coverage of the shielding material is 60% or more, suppress the noise radiation amount to 48 dBμV / m or less, and obtain particularly high noise shielding performance rated as A+.

[0074] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the present invention.

[0075] REFERENCE SIGNS LIST 1 Wire harness 2 Electric wire group 20 Communication electric wire 21 Insulated electric wire 21a Conductor 21b Insulating coating 3 Drain wire (ground wire) 4 Base material 5 Shielding material 51 Metal layer 52 Resin film 53 Adhesive layer 5a Exposed area 5b Adhesive area 9 Vehicle body structural member

Claims

1. A wire harness comprising: an electric wire group including a plurality of communication electric wires; a ground wire having a conductor wire and connectable to a ground potential; a substrate; and a sheet-like shielding material having 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 in electrical contact with the metal layer of the shielding material.

2. The wire harness as described in claim 1, wherein the ground wire is configured as a drain wire with the conductor wire exposed, and is covered by the shielding material together with the group of electric wires, and is in electrical contact with the metal layer of the shielding material directly or through a conductive layer.

3. The wire harness according to claim 2, wherein the shielding material further has a resin film, the metal layer is provided on a surface of the resin film, and the surface on which the metal layer is provided faces inward to cover the group of electric wires and the drain wire.

4. The wire harness as described in claim 3, wherein the shielding material further has an adhesive layer made of an adhesive on a surface of the metal layer, and the shielding material is fixed to each of the base material, the group of electric wires and the drain wire by the adhesive layer.

5. The wire harness according to claim 4, wherein the adhesive layer is insulating, and the metal layer has an exposed area where the adhesive layer is not formed on the surface at least in a portion covering the drain wire, and is in direct contact with the drain wire in the exposed area, thereby making electrical contact with the drain wire.

6. The wire harness according to claim 5, wherein the adhesive layer is formed in a regular pattern on the surface of the metal layer.

7. The wire harness according to claim 6, wherein the pattern is a striped pattern.

8. The wire harness according to claim 5, wherein an area ratio of the region where the adhesive layer is formed on the surface of the metal layer is 40% or more and 70% or less.

9. The wire harness according to claim 5, wherein the metal layer has a thickness of 15 μm or more.

10. The wire harness according to claim 5, wherein the thickness of the adhesive layer is 20 μm or less.

11. The wire harness according to claim 4, wherein the adhesive layer is conductive.

12. The wire harness according to claim 11, wherein the metal layer has a thickness of 10 μm or more.

13. A wire harness as claimed in any one of claims 1 to 12, 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.

14. A wire harness according to any one of claims 1 to 12, wherein the communication electric wire is configured as a parallel electric wire in which a pair of insulated electric wires are arranged with their axes aligned.

15. A wire harness according to any one of claims 1 to 12, wherein the group of electric wires includes six or more of the communication electric wires.

16. The wire harness according to any one of claims 1 to 12, which is arranged in two or more layers.

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