Electromagnetic shield structure and method for manufacturing the electromagnetic shield structure

Abstract

To provide an electromagnetic shield structure which has good connection workability, and also has excellent wiring workability thereafter.SOLUTION: In an electromagnetic shield pipe 1, a resin inner layer 3 is formed on the innermost layer, a metal layer 5 is formed on the outer periphery of the inner layer 3, and a resin outer layer 7 is formed on the outer periphery of the metal layer 5. In the electromagnetic shield pipe 1, the outer layer 7 is removed from the end by a predetermined length. Specifically, the metal layer 5 is exposed only in a predetermined range to the end of the electromagnetic shield pipe 1. The end of the electromagnetic shield pipe 1 is inserted to the end of a braided wire 13. The electromagnetic shield pipe 1 and the braided wire 13 are joined to each other by a weld part 11.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an electromagnetic shield structure having electric wires routed therein and used, for example, in an electric vehicle. [Background technology]

[0002] Conventionally, metal pipes such as steel pipes and aluminum pipes, or corrugated plastic pipes have been used as protective tubes for cables. In these cases, problems can arise with noise generated by the cables housed in the protective tubes, or the effect of external noise on the cables inside. For example, in hybrid vehicles, a protective tube is installed under the vehicle body to fit the shape of the vehicle body to protect the cables that supply three-phase AC output from the inverter device to the drive motor. In this case, shielding measures are necessary to prevent noise generated by the cables from affecting radios and other devices.

[0003] Such an electromagnetic shielding structure uses a metal electromagnetic shielding tube, and the end of the electromagnetic shielding tube is covered with and connected to a flexible conductor such as a braided wire. In this state, by tightening a ring-shaped member from the outer periphery, electrical continuity between the metal layer and the flexible conductor can be established and the flexible conductor can be connected to the metal layer (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-120917 Summary of the Invention [Problem to be solved by the invention]

[0005] As in Patent Document 1, by using a flexible conductor, the electric wires inserted inside the electromagnetic shielding tube and the connection parts with other electrical equipment can be covered with the conductor, thereby ensuring the shielding properties of the connection parts.

[0006] However, because a crimping ring must be used to connect the electromagnetic shielding tube and the flexible conductor, the number of parts increases. Furthermore, because the crimping ring must be pre-inserted, forgetting to do so requires going back through the process. Furthermore, in Patent Document 1, the crimping ring is a so-called ear clamp, and the ear portion protrudes beyond the outer diameter of the electromagnetic shielding tube after clamping. Therefore, there is a risk that the ear portion may get in the way of routing the cable in a vehicle or the like.

[0007] The present invention has been made in view of the above problems, and has as its object to provide an electromagnetic shield structure and the like which has good connection workability and is also excellent in subsequent wiring workability. [Means for solving the problem]

[0008] To achieve the above-mentioned objectives, 1st The invention relates to an electromagnetic shielding structure in which an electric wire can be inserted therein and in which an electromagnetic shielding tube and a braided wire are connected, the electromagnetic shielding tube having a metal layer and a resin outer layer formed on the outer periphery of the metal layer, the outer layer being removed at the end of the electromagnetic shielding tube to expose the metal layer, and the end of the electromagnetic shielding tube is inserted into the end of the braided wire, so that the metal layer and the braided wire are connected. , by spot welding by resistance welding, ultrasonic welding or laser welding. Characterized by being bonded and It is an electromagnetic shielding structure. The metal layer and the braided wire are preferably welded by resistance welding, ultrasonic welding, or laser welding. According to the first aspect of the present invention, the metal layer and the braided wire are joined by spot welding using a laser or the like, thereby suppressing the thermal effects during joining.

[0009] It is desirable that the inner diameter of the electromagnetic shielding tube at the joint between the metal layer and the braided wire is substantially the same as the inner diameter of the electromagnetic shielding tube at other locations.

[0010] A second invention is a method for manufacturing an electromagnetic shielding structure in which an electromagnetic shielding tube and a braided wire are connected, the electromagnetic shielding tube having a metal layer and a resin outer layer formed on the outer periphery of the metal layer, the method comprising removing the outer layer at an end of the electromagnetic shielding tube to expose the metal layer, inserting the metal layer at the end of the electromagnetic shielding tube into the braided wire, arranging an excess portion of the braided wire on the outer periphery of the outer layer, folding back the excess portion, and then welding from the outer periphery of the folded-back portion to join the metal layer and the braided wire. According to the second invention, folding back the excess portion and welding can improve the weldability and shielding properties of the joint. The metal layer and the braided wire may be joined by spot welding using resistance welding, ultrasonic welding, or laser welding.

[0011] According to the present invention, the braided wire and the metal layer are joined by welding, so there is no need to use any other member, and no need for a leading-through operation.

[0012] Furthermore, unlike ear clamps, there are no protruding parts, making subsequent installation easier. For example, because there are no protruding parts on the outer periphery of the shield structure, installation in a vehicle can be done in a space-saving manner.

[0013] Furthermore, if the inner diameter of the electromagnetic shielding tube at the joint between the metal layer and the braided wire is approximately the same as the inner diameter of the electromagnetic shielding tube at other locations, there is no hindrance when inserting an electric wire into the inside. For example, in conventional crimping methods, the diameter of the electromagnetic shielding tube is reduced at the connection portion, and the diameter of the electric wire that can be inserted is determined taking into account the inner diameter of this reduced diameter portion. As a result, unnecessary gaps are formed between the electric wire and the electromagnetic shielding tube at locations other than the connection portion. However, if there is no reduced diameter portion, an electromagnetic shielding tube of an appropriate size for the diameter of the electric wire inside can be used even at locations other than the connection portion, allowing for more space-saving installation in a vehicle. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide an electromagnetic shield structure and the like that has good connection workability and is also excellent in subsequent wiring workability. [Brief explanation of the drawings]

[0015] [Figure 1] 1A is a perspective view showing the electromagnetic shielding tube 1, and FIG. 1B is a cross-sectional view taken along line AA in FIG. [Figure 2] 2 is a longitudinal cross-sectional view of the electromagnetic shielding tube 1, taken along line BB in FIG. 1(a). [Figure 3] 4(a) and 4(b) are diagrams showing a process of connecting a braided wire to an electromagnetic shielding tube 1. FIG. [Figure 4] 1 is a diagram showing an electromagnetic shielding structure 10. FIG. [Figure 5] 1A and 1B are diagrams showing the electromagnetic shield structure 10 in use. DETAILED DESCRIPTION OF THE INVENTION

[0016] An electromagnetic shielding tube 1 according to an embodiment of the present invention will be described below. Fig. 1(a) is a perspective view of the electromagnetic shielding tube 1, and Fig. 1(b) is a cross-sectional view perpendicular to the longitudinal direction of the electromagnetic shielding tube 1, taken along line AA in Fig. 1(a). Fig. 2 is a cross-sectional view of the electromagnetic shielding tube 1 in the longitudinal direction, taken along line BB in Fig. 1.

[0017] The electromagnetic shielding tube 1 has an inner layer 3 made of resin formed as the innermost layer, a metal layer 5 formed on the outer periphery of the inner layer 3, and an outer layer 7 made of resin formed on the outer periphery of the metal layer 5. In other words, the metal layer 5 made of metal is formed between the inner layer 3 and the outer layer 7. Note that the inner layer 3 is not necessarily required. If the inner layer 3 is provided, an adhesive layer is provided at the interface between the inner layer 3 and the metal layer 5. Since the inner layer 3 is significantly affected by distortion due to the difference in linear expansion coefficient between it and the metal layer 5, it is preferable to interpose an adhesive layer or the like between the inner layer 3 and the metal layer 5.

[0018] On the other hand, it is preferable that no adhesive layer is formed at the interface between the metal layer 5 and the outer layer 7. This allows the outer layer 7 alone to be easily peeled off, and prevents the metal layer 5 from peeling off and breaking along with the outer layer 7 when the outer layer 7 is peeled off. Therefore, the outer layer 7 at the end of the electromagnetic shielding tube 1 can be easily peeled off.

[0019] The outer layer 7 of the electromagnetic shielding tube 1 is removed by a predetermined length from the end. That is, a predetermined range of the metal layer 5 is exposed at the end of the electromagnetic shielding tube 1. The exposed metal layer 5 is the portion to which a braided wire, which is a flexible conductor, is connected. The shielding structure to which the braided wire is connected will be described later.

[0020] The resins constituting the inner layer 3 and the outer layer 7 may be the same or different. The resin may be crosslinked or modified. For example, the resin may be crosslinked to improve heat resistance, or may be modified with maleic acid to improve adhesion. A flame retardant such as a halogen-based, phosphorus-based, or metal hydrate may be added, or titanium oxide or the like may be added to improve weather resistance.

[0021] Such flame retardants and additives for improving weather resistance may be added only to the resin constituting the outer layer 7. In other words, they do not need to be added to the resin of the inner layer 3, which does not require flame retardancy or weather resistance.

[0022] Metal layer 5 may be made of copper or iron as long as it can provide a shielding effect, but it is preferable to use aluminum (including aluminum alloys) in consideration of weight reduction and bendability.

[0023] The metal layer 5 is formed, for example, by forming a thin metal plate (including a metal sheet) as a strip-shaped member using a forming machine, feeding the thin metal plate (including a metal sheet) onto the outer periphery of the resin pipe of the inner layer 3 so that the ends butt together, forming a cylindrical shape, and then welding the butt joint of the strip-shaped member with a welding machine. By manufacturing in this manner, a joint 9 is formed in a part of the metal layer 5, as shown in Fig. 1(b). Therefore, in the cross section shown in the figure, no gaps are formed in the metal layer 5 that forms the shielding layer.

[0024] Next, we will explain a method for manufacturing an electromagnetic shield structure using the electromagnetic shield tube 1 of the present invention. First, as shown in Figure 3(a), the end of the electromagnetic shield tube 1 (metal layer 5) is inserted into the end of the tubular braided wire 13.

[0025] In this state, the overlapping portion of the electromagnetic shielding tube 1 and the braided wire 13 is welded from the outside, as shown in Fig. 3(b). Note that before welding, the excess length of the braided wire 13 may be placed around the outer periphery of the outer layer 7 and temporarily fixed with a temporary fixing ring or band. In this way, the metal layer 5 and the braided wire 13 are joined by the welded portion 11.

[0026] As a welding method, for example, laser welding can be used. Laser welding allows for localized heating in a short time. This can suppress, for example, deterioration and thermal distortion caused by cracking of the outer layer 7. Furthermore, because the heat source is light, there is little influence from current, voltage, magnetic force, etc.

[0027] It is not necessary to form welds 11 over the entire overlapping area between metal layer 5 and braided wire 13. For example, welds 11 may be formed in spots at multiple locations as long as sufficient electrical continuity between braided wire 13 and metal layer 5 is ensured. This can further reduce the thermal effects.

[0028] The welding method is not limited to laser welding, and other methods may be used. For example, resistance welding or ultrasonic welding can provide a good appearance after welding and can reduce the thickness of the welded portion.

[0029] The outer diameter (D in the figure) at the joint between the metal layer 5 and the braided wire 13 is smaller than the outer diameter (C in the figure) of the outer layer 7. Therefore, there is no protrusion to the outside, and it does not get in the way during wiring work, etc.

[0030] Furthermore, the electromagnetic shielding tube 1 is not reduced in diameter at any position. That is, the inner diameter of the electromagnetic shielding tube 1 at the joint between the metal layer 5 and the braided wire 13 (i.e., the inner diameter of the inner layer 3) is substantially the same as the inner diameter of the electromagnetic shielding tube 1 at other positions. Therefore, there is no need to consider the reduced diameter portion when determining the diameter of the electric wire to be inserted inside, and the diameter of the electric wire that can be inserted relative to the cross-sectional area of ​​the electromagnetic shielding tube 1 can be made larger than in the case where there is a reduced diameter portion. Furthermore, because there is no reduction in diameter (deformation of the metal layer 5), damage to the adhesive layer between the inner layer 3 and the metal layer 5 can be suppressed.

[0031] Finally, as shown in Fig. 4, the excess braided wire 13 on the outer periphery of the outer layer 7 is folded back onto the outer periphery of the metal layer 5. As a result, an electric wire can be inserted inside, and an electromagnetic shielding structure 10 can be obtained in which the electromagnetic shielding tube 1 and the braided wire 13 are connected. Alternatively, the braided wire 13 may be placed over the metal layer 5, the excess length at the end folded back, and then welding may be performed from the outer periphery of the folded back portion.

[0032] Next, an example of use of the electromagnetic shielding structure 10 will be described. Fig. 5 is a partial cross-sectional view showing the electromagnetic shielding structure 10. An electric wire 21 is inserted inside the electromagnetic shielding tube 1. A terminal 23 is connected to the end of the electric wire 21, which is a covered wire. Note that the number of electric wires 21 is not limited to the example shown in the figure.

[0033] An electric wire 21 is drawn out from the end of the electromagnetic shielding tube 1. A terminal 23 of the electric wire 21 is connected to a connection device 25 that is the connection target. The connection device 25 is disposed, for example, inside a housing 19. The housing 19 is made of, for example, metal and has shielding properties.

[0034] One end of the braided wire 13 is placed over the outer periphery of the exposed portion of the metal layer 5 at the end of the electromagnetic shielding tube 1 and is connected to the metal layer 5 by welding. As described above, the braided wire 13 has shielding properties.

[0035] The other end of the braided wire 13 is connected to the housing 19. The braided wire 13 provides electrical continuity between the metal layer 5 and the housing 19. If necessary, a resin outer casing 17 is disposed so as to cover the electromagnetic shielding tube 1 and the braided wire 13.

[0036] In the illustrated electromagnetic shield structure 10, an example is shown in which one braided wire 13 is used to cover the electromagnetic shielding tube 1 (metal layer 5), but the present invention is not limited to this. For example, if the electric wire 21 is branched into multiple branches, a braided wire 13 can be used to cover each electric wire 21 and the connection target, and the multiple braided wires 13 can be overlapped and joined to the metal layer 5.

[0037] Furthermore, a member for ensuring watertightness may be disposed at the end of the exterior body 17 or the outer layer 7, for example.

[0038] As described above, according to this embodiment, there is no need to pre-pass the crimping member, which prevents the need to redo the work due to forgetting to pass the member through. Furthermore, unlike the crimping member, there is no protruding part to the outside, so it does not get in the way when attaching the exterior body 17 or when routing the wires in a vehicle. Furthermore, because the electromagnetic shielding tube 1 is not reduced in diameter, an electromagnetic shielding tube 1 of an appropriate size can be used for the diameter of the electric wire 21 inside.

[0039] Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical scope of the present invention is not limited to the above-described embodiments. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the technical ideas described in the claims, and it is understood that these modifications and alterations also fall within the technical scope of the present invention. [Explanation of symbols]

[0040] 1...Electromagnetic shielding tube 3...Inner layer 5……metal layer 7……Outer layer 9……Joint part 10...Electromagnetic shielding structure 11...Welded section 13……braided wire 17....Exterior body 19....Case 21……Electric wire 23...Terminal 25...Connected device

Claims

1. An electromagnetic shield structure in which an electric wire can be inserted inside and an electromagnetic shield tube and a braided wire are connected, the electromagnetic shielding tube has a metal layer and a resin outer layer formed on the outer periphery of the metal layer, an electromagnetic shielding structure, characterized in that the end of the electromagnetic shielding tube has the outer layer removed to expose the metal layer, the end of the electromagnetic shielding tube is inserted into the end of the braided wire, and the metal layer and the braided wire are joined by spot welding using resistance welding, ultrasonic welding, or laser welding.

2. 2. The electromagnetic shield structure according to claim 1, wherein the inner diameter of the electromagnetic shield tube at the joint between the metal layer and the braided wire is substantially the same as the inner diameter of the electromagnetic shield tube at other portions.

3. A method for manufacturing an electromagnetic shield structure in which an electromagnetic shield tube and a braided wire are connected, comprising: the electromagnetic shielding tube has a metal layer and a resin outer layer formed on the outer periphery of the metal layer, removing the outer layer at the end of the electromagnetic shielding tube to expose the metal layer; the metal layer at the end of the electromagnetic shielding tube is inserted into the braided wire, and an excess length of the braided wire is disposed around the outer periphery of the outer layer; a welding step of welding the metal layer and the braided wire from the outer periphery of the folded portion after folding back the excess length, thereby joining the metal layer and the braided wire together;

4. A method for manufacturing an electromagnetic shielding structure as described in claim 3, characterized in that the metal layer and the braided wire are joined by spot welding using resistance welding, ultrasonic welding or laser welding.

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