Electromagnetic shielding structure, method for manufacturing electromagnetic shielding 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 an adhesive 11 arranged in an overlapping part of the electromagnetic shield pipe 1 and the braided wire 13.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an electromagnetic shield structure or the like in which an electric wire is routed inside and is used, for example, in an electric vehicle.

Background Art

[0002] Conventionally, as a protective pipe for a cable, a metal pipe such as a steel pipe or an aluminum pipe, or a resin corrugated pipe has been used. At this time, the influence of noise generated from the cable accommodated in the protective pipe and the influence of external noise on the internal cable may be a problem. For example, in a hybrid vehicle, in order to protect a cable that supplies a three-phase AC output from an inverter device to a drive motor, a protective pipe is piped in the lower part of the vehicle body or the like in accordance with the shape of the vehicle body. At this time, since noise enters a radio or the like due to noise generated from the cable, shielding measures are necessary.

[0003] As such an electromagnetic shield structure, a metal electromagnetic shield pipe is used, and at the end of the electromagnetic shield pipe, a flexible conductor such as a braided wire is covered and connected. In this state, by tightening with a ring-shaped member from the outer periphery, conduction between the metal layer and the flexible conductor can be achieved, 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

Summary of the Invention

Problems to be Solved by the Invention

[0005] By using a flexible conductor as in Patent Document 1, the connection portion between the electric wire inserted inside the electromagnetic shield pipe and other electric devices can be covered with a conductor, so that the shielding property of the connection portion can be ensured.

[0006] However, since caulking is required for connecting the electromagnetic shielding tube and the flexible conductor, there is a problem in that the number of components increases. Further, since caulking requires threading through, if the threading through is forgotten, it is necessary to go back in the process. Further, in Patent Document 1, since the caulking is a so-called ear clamp, the ear portion protrudes from the outer diameter of the electromagnetic shielding tube after clamping. For this reason, there is a risk that the ear portion may interfere with the layout when arranging it in a vehicle or the like.

[0007] The present invention has been made in view of such problems, and an object thereof is to provide an electromagnetic shielding structure or the like having good connection workability and excellent subsequent layout workability.

Means for Solving the Problems

[0008] In order to achieve the above-described object, a first invention is an electromagnetic shielding structure in which an electric wire can be inserted inside and an electromagnetic shielding tube and a braided wire are connected, wherein the electromagnetic shielding tube has a metal layer and a resin outer layer formed on the outer periphery of the metal layer, and at an end portion of the electromagnetic shielding tube, the outer layer is removed and the metal layer is exposed, and the end portion of the electromagnetic shielding tube is inserted into the end portion of the braided wire, and the metal layer and the braided wire are joined by a conductive adhesive and the outer surface of the metal layer at the joint with the braided wire is roughened, the adhesive has thermosetting or photocuring properties, and the heat resistance temperature is 120 °C or higher and is an electromagnetic shielding structure characterized by that.

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

[0010] The outer surface of the metal layer at the joint portion with the braided wire may be roughened.

[0011] According to the first invention, since the braided wire and the metal layer are connected by an adhesive, it is not necessary to use other members, and the threading through operation is also unnecessary.

[0012] In addition, since there is no protruding portion like an ear clamp, subsequent routing work is also easy. For example, since there is no protruding portion on the outer peripheral portion of the shield structure, it is possible to route it in a space-saving manner when routing it in a vehicle.

[0013] Also, if 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 parts, it will not hinder the insertion of the electric wire inside. For example, in the conventional caulking method, the electromagnetic shield tube at the connection part is reduced in diameter, so considering the inner diameter of this reduced-diameter part, the diameter of the electric wire that can be inserted is determined. Therefore, at parts other than the connection part, an unnecessary gap is formed between the electric wire and the electromagnetic shield tube. However, if there is no reduced-diameter part, an electromagnetic shield tube with an appropriate size can be used for the inner electric wire diameter even at parts other than the connection part, so it is possible to route it in a more space-saving manner when routing it in a vehicle.

[0014] Also, if the outer surface of the metal layer at the joint with the braided wire is roughened, the bonding strength between the braided wire and the metal layer by the adhesive can be increased.

[0015] The second invention is a method for manufacturing an electromagnetic shield structure capable of inserting an electric wire inside, comprising a step of removing the outer layer at the end of an electromagnetic shield tube having a metal layer and a resin outer layer formed on the outer periphery of the metal layer, a step of inserting the end of the electromagnetic shield tube into the end of a braided wire, and a step of connecting the electromagnetic shield tube and the braided wire with a conductive adhesive. and the adhesive has thermosetting or photocuring properties, the heat resistance temperature is 120 °C or higher, the outer surface of the metal layer at the joint with the braided wire is roughened, and by using a profile and injecting the adhesive into the interior of the profile, the metal layer and the braided wire are adhered It is a method for manufacturing an electromagnetic shield structure, characterized by the above.

[0016] When curing the adhesive, the braided wire may be held in a state of being pressed against the metal layer by an auxiliary member so that the metal layer does not deform.

[0017] According to the second invention, since it is not necessary to pre-pass the caulking member, the work is easy.

[0018] Also, when curing the adhesive, by holding the braided wire pressed against the metal layer by an auxiliary member so that the metal layer does not deform, the electrical connection between the braided wire and the metal layer can be surely maintained and they can be adhered together.

Advantages of the Invention

[0019] According to the present invention, an electromagnetic shield structure or the like with good connection workability and excellent subsequent routing workability can be provided.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0021] Hereinafter, the electromagnetic shield tube 1 according to the embodiment of the present invention will be described. FIG. 1(a) is a perspective view of the electromagnetic shield tube 1, and FIG. 1(b) is a cross-sectional view perpendicular to the longitudinal direction of the electromagnetic shield tube 1 and is a cross-sectional view taken along line A-A of FIG. 1(a). Also, FIG. 2 is a cross-sectional view in the longitudinal direction of the electromagnetic shield tube 1 and is a cross-sectional view taken along line B-B of FIG. 1.

[0022] The electromagnetic shielding tube 1 has an inner layer 3 made of resin formed on 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. That is, it is configured by forming a metal layer 5 made of metal between the inner layer 3 and the outer layer 7. Note that the inner layer 3 is not necessarily essential. When 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 greatly affected by the strain due to the difference in the linear expansion coefficient from 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.

[0023] 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. By doing so, only the outer layer 7 can be easily peeled off, and it is possible to prevent the metal layer 5 from being peeled off and broken together 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.

[0024] The outer layer 7 of the electromagnetic shielding tube 1 is removed by a predetermined length from the end. That is, at the end of the electromagnetic shielding tube 1, the metal layer 5 is exposed by a predetermined range. The exposed metal layer 5 becomes a part to which a braided wire, which is a flexible conductor, is connected. Note that, in order to increase the contact area with the braided wire and enhance the bonding strength with an adhesive to be described later, knurling, embossing, grooving, blasting, etching, plating treatment, etc. (collectively referred to as roughening treatment for forming some kind of unevenness on the surface) may be formed on the outer peripheral surface of the exposed portion of the metal layer 5. The shield structure to which the braided wire is connected will be described later.

[0025] The resins constituting the inner layer 3 and the outer layer 7 may be the same resin or different resins. Note that the resin may be crosslinked or modified. For example, it may be crosslinked to improve heat resistance, or may be maleic acid modified to improve adhesiveness. Further, 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.

[0026] In addition, such flame retardants, additives for improving weather resistance, etc. may be added only to the resin constituting the outer layer 7. That is, it is not necessary to add them to the resin of the inner layer 3 that does not require flame retardancy or weather resistance.

[0027] For the metal layer 5, if it is possible to obtain a shielding effect, copper or iron may be used. However, considering weight reduction, bendability, etc., it is desirable to make it of aluminum (including aluminum alloy).

[0028] For example, the metal layer 5 is formed by using a forming processing machine to form a metal thin plate (including a metal sheet) which is a strip-shaped member while feeding it around the outer circumference of the resin tube of the inner layer 3 in a cylindrical shape so that the ends are butted against each other, and the butting portion of the strip-shaped member is welded by a welding machine. By manufacturing in this way, as shown in FIG. 1(b), a joint portion 9 is formed in a part of the metal layer 5. Therefore, in the cross section shown in the figure, no gap is formed in the metal layer 5 forming the shielding layer.

[0029] Next, a method for manufacturing an electromagnetic shielding structure using the electromagnetic shielding tube 1 of the present invention will be described. First, as shown in FIG. 3(a), a conductive adhesive 11 is disposed on the outer circumference of the metal layer 5. When disposing the adhesive 11 in a predetermined range with a predetermined thickness, for example, a ring-shaped profile may be used. By disposing a profile having a space in the disposed portion of the adhesive 11 on the outer circumference of the metal layer 5 and injecting the adhesive 11 into the inside of the profile, the adhesive 11 can be disposed in a desired range. If the material of the profile has a release property with respect to the adhesive 11, the profile can be easily removed after the adhesive 11 is disposed.

[0030] Note that the material of the adhesive 11 is not particularly limited as long as it has conductivity, and it may be thermosetting or photocurable, for example, an epoxy resin. Also, an adhesive in the form of a powder may be arranged, heated to be melted, and then thermoset. However, in order to avoid contact failure due to siloxane, silicone-based adhesives are not desirable. Further, for example, for use in an engine room of a vehicle or the like, the heat-resistant temperature is desirably 120°C or higher. Note that the adhesive in the present invention includes adhesives.

[0031] As the adhesive 11, it can be arranged over the entire exposed metal layer 5. For example, unlike a caulking material, it is not necessary to arrange it at a position a predetermined distance away from the tip of the metal layer 5, and the adhesive 11 can be arranged in alignment with the tip of the metal layer 5. Therefore, it is easy to align the position of the adhesive 11, and it is also easy to automate the application of the adhesive 11.

[0032] Note that in order to suppress the outflow of the adhesive 11 and the excessive penetration into the braided wire 13, the adhesive 11 needs to have a certain degree of viscosity. For example, in the state where the adhesive 11 is applied, it is desirable to have a viscosity such that it does not flow down by its own weight from the application range.

[0033] Next, as shown in FIG. 3(b), the end portion (metal layer 5) of the electromagnetic shield tube 1 is inserted into the end portion of the tubular braided wire 13. That is, the adhesive 11 is arranged between the braided wire 13 and the metal layer 5.

[0034] In this state, as shown in FIG. 4(a), the overlapping portion of the electromagnetic shield tube 1 and the braided wire 13 is pressed from the outside by the auxiliary member 15, and the adhesive 11 is cured in a state where the braided wire 13 is pressed against the metal layer 5. The auxiliary member 15 is in a ring shape and is a member that holds the braided wire 13 pressed against the metal layer 5 with a pressing force such that the metal layer 5 does not deform when the adhesive 11 is cured.

[0035] When the adhesive 11 hardens, the metal layer 5 and the braided wire 13 are joined by the conductive adhesive 11. At this time, if the outer surface of the metal layer 5 at the joint with the braided wire 13 is previously roughened, the bonding strength at the time of bonding can be increased.

[0036] In addition, 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. For this reason, there is no protruding portion to the outside, and it does not get in the way in wiring work or the like.

[0037] Also, the electromagnetic shield tube 1 is not reduced in diameter at any position. That is, the inner diameter of the electromagnetic shield tube 1 (that is, the inner diameter of the inner layer 3) at the joint between the metal layer 5 and the braided wire 13 is substantially the same as the inner diameter of the electromagnetic shield tube 1 at other portions. For this reason, there is no need to consider a reduced diameter portion with respect to the diameter of the electric wire inserted inside, and the diameter of the electric wire that can be inserted with respect to the cross-sectional area of the electromagnetic shield tube 1 can be increased compared to the case where there is a reduced diameter portion. Further, since there is no diameter reduction (deformation of the metal layer 5), it is possible to suppress damage to the adhesion between the inner layer 3 and the metal layer 5.

[0038] Finally, as shown in FIG. 4(b), the excess braided wire 13 on the outer peripheral side of the outer layer 7 is folded back to the outer peripheral side of the metal layer 5. Thus, an electromagnetic shield structure 10 in which an electric wire can be inserted inside and the electromagnetic shield tube 1 and the braided wire 13 are connected can be obtained.

[0039] Note that the manufacturing method of the electromagnetic shield structure 10 is not limited to the above-described steps. FIG. 5(a) is a diagram showing another manufacturing method of the electromagnetic shield structure 10. In the present embodiment, the braided wire 13 is directly placed on the outer periphery of the metal layer 5 with the outer layer 7 at the tip removed and exposed.

[0040] Thereafter, an adhesive 11 is disposed on the outer periphery of the braided wire 13 that overlaps with the metal layer 5. Even in this case, the adhesive 11 may be applied to the tip position of the metal layer 5 using a profile. By injecting the adhesive 11 into the profile under a predetermined pressure, the adhesive 11 can penetrate into the braided wire 13 and ooze out to the surface side of the metal layer 5. Before applying the adhesive 11, the excess length portion of the braided wire 13 may be disposed on the outer periphery of the outer layer 7 and temporarily fixed with a temporary fixing ring or band.

[0041] In this state, by curing the adhesive 11 while pressing the braided wire 13 with the auxiliary member 15, the braided wire 13 and the metal layer 5 can be joined to obtain a shield structure. Note that the metal layer 5 may be covered with the braided wire 13, and after folding back the excess length at the end, the adhesive 11 may be disposed on the outer peripheral portion of the folded-back portion. For example, if the uncured adhesive 11 penetrates excessively in the axial direction of the braided wire 13, the amount of the adhesive may be insufficient and the adhesive strength may decrease. Also, when pressing with the auxiliary member 15, there is a risk of leakage from the application position of the adhesive 11. Therefore, instead of removing all of the outer layer 7 at the tip of the electromagnetic shield tube 1, a part of the outer layer 7 at the tip may be left and the outer layer 7 within a predetermined length range may be removed.

[0042] Next, an example of using the electromagnetic shield structure 10 will be described. FIG. 6 is a partial cross-sectional view showing the electromagnetic shield structure 10. Inside the electromagnetic shield tube 1, an electric wire 21 is inserted. 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 illustrated example.

[0043] The electric wire 21 is drawn out from the end of the electromagnetic shield tube 1. The terminal 23 of the electric wire 21 is connected to a connection device 25 which is a connection target. Note that the connection device 25 is disposed inside a housing 19, for example. The housing 19 is made of metal, for example, and has shielding properties.

[0044] One end of the braided wire 13 is covered on the outer periphery of the exposed portion of the metal layer 5 at the end of the electromagnetic shield tube 1 and is connected to the metal layer 5 by the adhesive 11. As described above, the braided wire 13 has shielding properties.

[0045] The other end of the braided wire 13 is connected to the housing 19. Through the braided wire 13, the metal layer 5 and the housing 19 are electrically connected. Further, if necessary, a resin exterior body 17 is arranged so as to cover the electromagnetic shielding tube 1 and the braided wire 13.

[0046] In the illustrated electromagnetic shielding structure 10, an example in which one braided wire 13 is used by covering the electromagnetic shielding tube 1 (metal layer 5) is shown, but the present invention is not limited to this. For example, when the electric wire 21 is branched into a plurality of wires, braided wires 13 that cover each electric wire 21 and the connection target can be used, and the plurality of braided wires 13 can be overlapped and joined to the metal layer 5.

[0047] Also, members for ensuring water stoppage may be arranged at the ends of the exterior body 17, the outer layer 7, etc.

[0048] As described above, according to the present embodiment, since the work of passing through the caulking member is not required, it is possible to prevent rework due to omission of passing through. Further, since there is no protruding portion to the outside like the caulking member, it does not get in the way when attaching the exterior body 17 or when arranging in a vehicle. Further, since the electromagnetic shielding tube 1 is not reduced in diameter, an electromagnetic shielding tube 1 having an appropriate size can be used with respect to the diameter of the internal electric wire 21.

[0049] As described above, the embodiments of the present invention have been described with reference to the accompanying drawings, but the technical scope of the present invention is not limited by the above-described embodiments. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope of the technical idea described in the claims, and it is naturally understood that those also belong to the technical scope of the present invention.

Explanation of Signs

[0050] 1...... Electromagnetic shielding tube 3...... Inner layer 5...... Metal layer 7...... Outer layer 9...... Joint part 10...... Electromagnetic shielding structure 11………Adhesive 13………Stranded wire 15………Auxiliary member 17………Outer package 19………Housing 21………Electric wire 23………Terminal 25………Connected device

Claims

1. An electromagnetic shielding structure that allows an electric wire to be inserted therein and in which an electromagnetic shielding tube and a braided wire are connected, wherein the electromagnetic shielding tube has a metal layer and a resin outer layer formed on the outer periphery of the metal layer, at the end of the electromagnetic shielding tube, the outer layer is 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 a conductive adhesive, the outer surface of the metal layer at the joint with the braided wire is roughened, and the adhesive has thermosetting or photocuring properties and a heat resistance temperature of 120° C. or higher. An electromagnetic shielding structure characterized by this.

2. The electromagnetic shielding structure according to claim 1, wherein 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 portions.

3. A method for manufacturing an electromagnetic shielding structure that allows an electric wire to be inserted therein, a step of removing the outer layer at the end of an electromagnetic shielding tube having a metal layer and a resin outer layer formed on the outer periphery of the metal layer, a step of inserting the end of the electromagnetic shielding tube into the end of a braided wire, a step of connecting the electromagnetic shielding tube and the braided wire with a conductive adhesive, comprising: the adhesive has thermosetting or photocuring properties and a heat resistance temperature of 120° C. or higher, the outer surface of the metal layer at the joint with the braided wire is roughened, and the metal layer and the braided wire are adhered by injecting the adhesive into the profile using the profile. A method for manufacturing an electromagnetic shielding structure characterized by this.

4. The method for manufacturing an electromagnetic shielding structure according to claim 3, wherein when the adhesive is cured, the braided wire is held in a state of being pressed against the metal layer by an auxiliary member so that the metal layer does not deform.

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