HOSE COMBINATION WITH ELECTROMAGNETIC SHIELDING, HOSE WITH ELECTROMAGNETIC SHIELDING AND USE OF SUCH A HOSE COMBINATION OR HOSE

Description

[0001] The invention relates to a hose combination with electromagnetic shielding according to the preamble of claim 1.

[0002] Such hose combinations are known per se from the prior art. They are used, for example, to protect electrical cables from the influence of electromagnetic interference or to shield current-carrying conductors from the environment. In addition to electromagnetic shielding, at least one other property is often desired, in particular the provision of protection against mechanical influences, for example abrasion resistance and / or impact resistance, heat resistance and the like. When using a hose combination, one hose can be designed with electromagnetic shielding in mind, while the other hose can be designed to achieve the at least one other property. However, this does not preclude both hoses from being designed with the other property in mind.

[0003] One area of ​​application for these hose combinations is automotive engineering, particularly the wiring of motor vehicles and, even more specifically, the wiring in the engine compartment of motor vehicles. These hose combinations are particularly advantageous in the latter case, as the available installation space is notoriously limited, and thus electromagnetic interference sources can have a significant impact on the environment. Furthermore, modern vehicles with electric or hybrid drives are increasingly installing so-called high-voltage electrical systems, which must be shielded from the environment.

[0004] At this point, it should be noted that the above-mentioned properties of the known hose combinations also apply to the hose combinations according to the invention.

[0005] Document US 2015 / 237770 A1 discloses a multilayer cable comprising an inner, a middle, and an outer layer. The inner and outer layers are formed from a resin, and the middle layer is formed from metal. Reference is also made to document WO 2012 / 036320 A1.

[0006] It is an object of the present invention to provide a hose combination of the type mentioned at the outset, which is particularly suitable for installation in confined spaces, for example for installation in the engine compartment of motor vehicles.

[0007] This object is achieved according to the invention by a hose combination according to claim 1.

[0008] With known hose combinations, the problem often arose that, due to the interlocking arrangement of the radially outer hose and the radially inner hose, the hose combination was difficult to bend in order to give it the shape required for arrangement in confined spaces. According to the invention, this problem is overcome by the radially inner hose being arranged loosely within the radially outer hose, or in such a way that it easily detaches from the radially outer hose when bent. According to the invention, the radially inner hose and the radially outer hose therefore have no connection to one another at all or, at most, adhere to one another slightly.

[0009] To ensure the electromagnetic shielding properties of the hose combination, a further development of the invention proposes that at least the radially inner hose has at least one electrically conductive layer. In this way, the radially inner hose responsible for the electromagnetic shielding is protected from damage by external influences solely by the presence of the radially outer hose, regardless of its precise design.

[0010] To achieve adequate electromagnetic shielding, it is advantageous if the electrically conductive layer is made of a material whose specific conductivity at a temperature of approximately 25°C is at least 30 MS / m. Advantageously, the electrically conductive layer can be made of copper and / or gold and / or silver. Furthermore, it is advantageous if the thickness of the electrically conductive layer is at least 20 µm. The electrically conductive layer can thus be formed, for example, from a foil of one of the aforementioned metals.

[0011] Since metal foils of this thickness are highly susceptible to damage, particularly tearing, it is advantageous if the electrically conductive layer is bonded to a stabilizing layer. In addition to mechanically stabilizing the electrically conductive layer, the stabilizing layer can also protect the electrically conductive layer from corrosion. In principle, it is conceivable to sandwich the electrically conductive layer between two such stabilizing layers. In this case, however, the problem of electrically contacting the electrically conductive layer arises, for example, to connect it to a connector, in particular the connector housing, and / or to the vehicle's ground.Therefore, it is also conceivable to alternatively provide the electrically conductive layer with an additional metal layer on the side facing away from the stabilizing layer, which ensures both corrosion resistance and electrical contactability of the electrically conductive layer. For example, a copper layer can be tinned, silvered, or gold-plated, for example by vapor deposition.

[0012] The stabilizing layer and the electrically conductive layer can be bonded together using an adhesion promoter or adhesive or by a thermal process. InIn a further development of the invention, it is proposed that the stabilizing layer be laminated onto the electrically conductive layer. For example, the stabilizing layer can be made of plastic, such as polyester or polyethylene terephthalate. Furthermore, the stabilizing layer and / or the adhesion promoter or adhesive can be colored, particularly in a signal color, such as orange.

[0013] Alternatively, however, it is also conceivable for the stabilizing layer to be formed as a carrier layer onto which the electrically conductive layer is, for example, vapor-deposited. For example, the carrier layer can be formed from a nonwoven fabric, preferably made of polyester fibers, in particular a spunbonded fabric, whose basis weight is preferably at most 100 g / m². One of the aforementioned metals can then be applied to this nonwoven fabric, for example by means of a vacuum process, in particular by means of thermal evaporation or sputtering. The nonwoven fabric can be single-layered or multi-layered.

[0014] If the stabilizing layer is arranged radially outside the electrically conductive layer, the stabilizing layer can protect the electrically conductive layer from damage by the radially outer hose, for example when the radially inner hose and the radially outer hose move relative to each other due to their loose arrangement when the hose combination is laid.

[0015] In In practice, it has proven advantageous if the ratio of the radial thickness of the electrically conductive layer to the radial thickness of the stabilizing layer is between approximately 0.75 and approximately 1.25. For example, the radial thickness of the stabilizing layer or carrier layer can be approximately 23 µm, which, with a radial thickness of the electrically conductive layer of 20 µm, results in a ratio value of approximately 0.87.

[0016] To ensure good deformability of the hose comprising the electrically conductive layer, it is further proposed that the radial thickness of the hose comprising the electrically conductive layer be at most 250 µm, preferably at most 100 µm, and even more preferably at most 50 µm. By selecting a radial thickness within the range specified above, the hose comprising the electrically conductive layer also contributes only slightly to the overall weight of the hose combination.

[0017] In order to be able to produce the hose having the electrically conductive layer in a simple manner, the invention proposes that it be formed from a flat material by folding. Such a manufacturing method is described, for example, in DE 10 2011 086 191 A1 by the applicant, the relevant disclosure of which is hereby incorporated by reference into this disclosure. To increase the mechanical stability of the connection between the two lateral edges of the flat material, it is provided that these are arranged so as to overlap one another. The overlap can, for example, amount to 10-15% of the circumferential length of the hose having the electrically conductive layer.

[0018] In general, but not according to the invention, it is also possible to produce the hose from the flat material by winding the flat material in a helical manner, for example by placing it in a helical manner around the cable to be protected. The same layer structure can be used for winding as for the folding described above. To retain the shielding properties, the flat material should overlap by approximately one-third of its width. To improve the shielding properties during winding, contact between the conductive layers can be ensured, for example, by folding the flat material lengthwise, for example around its longitudinal centerline. To be able to fix the flat material, it can also be provided with a conductive adhesive.

[0019] In order to electrically connect the electrically conductive layers of the two lateral edges, it is further proposed that one of the lateral edges of the sheet material be folded back, preferably folded back once. For example, if the electrically conductive layer forms the radially inner layer, this folding back—i.e., the folding of the sheet material onto itself—positions it radially outward, so that when the radially inner electrically conductive layer of the other lateral edge overlaps the respective edge in question, it comes into contact with the edge in question and is thus electrically connected.

[0020] To connect the two lateral edges, an adhesive tape can be used, for example, an adhesive tape arranged between the two overlapping lateral edges of the sheet material, or an adhesive tape covering the freely accessible lateral edge. If the electrical contact between the lateral edges of the sheet material is enabled by folding back one of the lateral edges, it is advantageous if the adhesive tape comprises at least one electrically conductive material.

[0021] Alternatively, or in addition to using such an adhesive tape, the two lateral edges can also be soldered or welded together, particularly using a laser welding process. In this case, the overlap could also be omitted, thereby achieving a more homogeneous structure of the hose with the electrically conductive layer.

[0022] Alternatively or additionally, the connection between the two overlapping lateral edges of the flat material can be reinforced by embossing. If the stabilizing or carrier layer and the electrically conductive layer are pierced at least at certain points during the embossing process, this can also create an electrical connection between the two lateral edges.

[0023] To enable variation in the diameter of the hose containing the electrically conductive layer, the invention provides for a predetermined circumferential section of the hose to be folded over or into the remaining circumferential section. The advantage of this folding lies in the expandability of the hose diameter if necessary. This need may arise, for example, if the hose needs to be pulled over a connector plug at one of its ends.

[0024] If the diameter of the hose containing the electrically conductive layer is expanded as described above, it can be secured, for example, simply by using a heat-shrink tube or shrink fabric as the radially outer hose, e.g., on the connector. If the hose has been expanded along its entire length, the diameter can be reduced again along the remaining length. This ensures clean installation, especially for use in the engine compartments of motor vehicles.

[0025] In automotive construction (e.g., in the engine compartment, body), so-called round-oval corrugated pipes are increasingly being used. These pipes have a cross-sectional area that is either round or oval in sections. In this case, the cross-sectional shape, but not the cross-sectional area of ​​the outer sheath, is changed, allowing the cables to be laid even in confined spaces. Due to its thin wall thickness, the hose combination according to the invention is very well suited for such applications.

[0026] The cable harnesses installed in motor vehicles are often more than 5 m long and extend through various sections of the vehicle, such as the engine compartment, the passenger compartment, the trunk, and so on. Different requirements for the protection of the cable harness lines may exist in these different sections. For example, heat protection is required in the engine compartment, while increased fire protection requirements may apply in the passenger compartment. In some cases, the passenger compartment also has pre-prepared ducts for the cable harness, meaning that additional protection may not be necessary here either. Therefore, it is advantageous if the properties of the hoses in the hose combination vary from section to section.

[0027] In a further development of the invention, it can be further provided that a layer made of a noise-damping material is arranged between the radially inner tube and the radially outer tube. The noise-damping material can be selected solely with a view to preventing the generation of noise and / or with a view to preventing the transmission of noise that has already occurred. For example, the noise-damping material can be a nonwoven, in particular a spunbond, preferably made of polyester fibers.

[0028] The radially outer hose is formed from a braid, knit, woven or warp-knitted fabric, preferably made of plastic fibers. Alternatively, the radially outer hose comprises an extruded plastic corrugated pipe. Furthermore, the radially outer hose can be made of multiple layers. As already mentioned, the radially outer hose can have impact protection properties and can therefore be made of aramid, for example. However, it can also serve as abrasion protection or UV protection and can therefore be made of polyurethane, for example. Other potentially desirable protective properties include fire protection, heat protection, vibration protection and bite protection, e.g. against marten bites.

[0029] In a further development of the invention, the hose combination, and in particular the radially inner hose of the hose combination, can be dimensioned such that the hose combination can be used as a so-called "combined shield." In such a combined shield, several current-carrying lines are typically protected by a common EMC shield (EMC - electromagnetic compatibility).

[0030] According to a further aspect, the invention relates to the use of a hose combination according to the invention for protecting electrical cables from the influence of electromagnetic interference sources and / or for shielding current-carrying conductors, particularly in the engine compartments of motor vehicles. Regarding the advantages achievable with these further aspects, reference is made to the above discussion of the hose combination according to the invention.

[0031] The invention will be explained in more detail below using an exemplary embodiment with reference to the accompanying drawing. Figure 1 shows a cross-sectional view of a first embodiment of a hose combination according to the invention; Figures 2a and 2b show schematic representations to explain the ability to change the diameter by folding or folding a hose; Figure 3 shows a schematic representation to explain the production of the radially inner hose of the hose combination according to the invention from an elongated strip material by folding it around its longitudinal axis; Figure 4 shows a cross-sectional view similar to Figure 1 a second embodiment of a hose combination according to the invention; Figure 5 shows a schematic representation of a measuring setup for determining the shielding attenuation of the radially inner hose of the Figure 1 and 4shown hose combinations; Figures 6 and 7 show the results of the shielding effectiveness measurement on the radially inner hose of the Figure 1 shown hose combination using the hose Figure 5 shown measurement setup.

[0032] In Figure 1 A first embodiment of a hose combination according to the invention is generally designated 100. The hose combination 100 comprises a radially outer hose 102 and a radially inner hose 104.

[0033] In the illustrated embodiment, the radially outer hose 102 is designed as a corrugated tube. For example, the corrugated tube can be made of polyurethane to provide abrasion protection for the radially inner hose 104.

[0034] In the illustrated embodiment, the radially inner tube 104 is formed as a multi-layer foil comprising an inner layer 106 and an outer layer 108. The inner layer 106 is formed from a copper foil, while the outer layer 108 is formed from a plastic film, for example, a polyester film, which is laminated onto the copper foil. The thickness d1 of the copper foil can be, for example, 20 µm, while the thickness d2 of the plastic film can be approximately 23 µm. The plastic film 108 protects the copper foil 106 not only from tearing but also from damage caused by contact with the radially outer tube 102.As a further protective measure, a further protective layer 110 can, if desired, also be provided between the radially outer tube 102 and the radially inner tube 104, which in the illustrated embodiment is only shown roughly schematically in dashed lines and can be formed, for example, by a nonwoven, in particular a nonwoven with the properties explained at the outset.

[0035] As in Figure 1 As shown, the radially inner tube 104 is not formed with a continuous closed surface. Rather, it is made from a flat strip material 112 by folding it around its longitudinal axis A, as shown schematically in Figure 3 The two lateral edge regions 112a and 112b overlap by a circumferential angle α (see Figure 1), which can be up to 50° or more. This overlap has the advantage of improving the electromagnetic shielding properties of the copper foil 106.

[0036] In order to further improve the electromagnetic shielding properties of the copper foil 106, it is advantageous if the two lateral edge regions 106a and 106b of the copper foil 106 abut one another in such a way that they are in electrically conductive contact with one another. For this purpose, one of the two edge regions, edge region 106a in the illustrated embodiment, can be folded over, i.e., folded back on itself, whereby the copper foil 106 is brought from radially inward to radially outward in the area of ​​the foldback. It is thus in electrically conductive contact in the overlap region α with the copper foil of the edge region 106b lying directly on it.

[0037] In order to mechanically connect the two edge regions 112a and 112b of the strip material 112 from which the radially inner tube 104 is formed, an adhesive tape 114 is also provided. Additionally or alternatively, however, it is also conceivable to connect the two edge regions 112a and 112b by soldering or welding. Furthermore, it is conceivable to arrange an electrically conductive, double-sided adhesive tape between the edge regions 106a and 106b of the copper foil 106.

[0038] In order to be able to change the diameter of the radially inner tube 104 if necessary, as shown in Figure 2a As shown, a predetermined circumferential section 104a of the tube 104 can be folded over onto the remaining circumferential section. Alternatively, however, it is also conceivable to fold the predetermined circumferential section 104b into the remaining tube 104 (see Figure 2b ).

[0039] In Figure 4a simplified second embodiment of a hose combination according to the invention is shown, which essentially corresponds to the first embodiment according to Figure 1 speaks. Therefore, in Figure 4 analogous parts are provided with the same reference numerals as in Figure 1 , but increased by the number 100. In addition, the hose combination 200 of the Figure 4 are described below only insofar as they differ from the hose combination 100 according to Figure 1 to whose description express reference is hereby made.

[0040] For hose combination 200 according to Figure 4The radially outer tube 202 is formed from a knitted fabric, which can be made, for example, from aramid fibers, in order to provide impact protection for the radially inner tube 204. In addition, the radially inner tube 204 comprises a fleece 208, which is vapor-deposited with a copper layer 206. The radially inner tube 204 of the embodiment according to Figure 4 can be done using the Figure 3 be made from a strip material 212 using the method shown. However, the edge regions 212a and 212b of the strip material 212 abut one another without overlapping and are mechanically connected to one another by means of an adhesive tape 214.

[0041] The shielding capacity of the radially inner tube 104 or 204 can be described by the so-called shielding attenuation. This shielding attenuation is the ratio of the interference power in the room to the maximum power generated within the line / cable surrounded by the tube. More precisely, the shielding attenuation is the ratio of the electric field strength outside the tube to the electric field strength inside the tube. It is expressed in "dB."

[0042] The shielding attenuation can be determined using the so-called parallel wire method according to VG 95214-6 with the Figure 5The test specimen 305 was the inner conductor of a coaxial cable whose shielding had previously been removed and replaced by the radially inner tube 104 or 204 according to the invention. The test specimen 305 was connected to two measuring fixtures 304 and 306, which in the specific test setup were formed by two brass plates with soldered N-type sockets. The inner conductor of the coaxial cable ran through the N-type sockets, while the tube was electrically connected to the N-type sockets by means of screw clamps. A parallel wire 308 serving as an interference source also ran between the measurement recordings 304 and 306. The interference power was applied to the parallel wire 308 by a network analyzer 301 (RF generator from Rohde & Schwarz, type SMA100C, identification no. 2.81.01, calibrated 06 / 2012; and a test receiver from Rohde & Schwarz, type ESU8, identification no. 2.70.05, calibrated 09 / 2011) via a power divider 302 and the measuring pickup 306. In addition, the parallel wire 308 was connected to the measuring pickup 304 with a terminating impedance 310 (Spinner, type 50Ω / 25W, identification no. 5.10.01, calibrated 10 / 2012). The test object 305 was connected to the measurement fixture 306 via a shielding tube 307 to a shielding housing 309 equipped with a terminating impedance (Rosenberger, type 50 Ω / 0.25 W, identification no. 5.10.16, calibrated 10 / 2012). At the measurement fixture 304, the test object 305 was connected via another shielding tube 307 to a shielding housing 303, through which the signal induced in the test object 305 was fed to the network analyzer 301. If necessary, a power amplifier a could also be provided between the shielding housing 303 and the network analyzer. The measurements were performed on a wooden table in a shielded test booth. The shielding attenuation was measured in the frequency range from 10 kHz to 300 MHz.The measurement was carried out in a state of the radially inner tube 104 or 204 according to the invention in which it had a diameter of 20 mm.

[0043] The measurement result for the radially inner tube 104 according to Figure 1 is in Figure 6 while the measurement result for the radially inner tube 204 is shown according to Figure 4 in Figure 7 Although both tubes 104 and 204 exhibit excellent attenuation of better than -70 dB over the entire frequency range from 10 kHz to 300 MHz, it can be seen that tube 104 according to Figure 1 due to the overlap and the electrical contacting of the two edge regions 106a and 106b of the copper foil 106, it has better shielding properties in the high frequency range than the tube 204 according to Figure 4 .

Claims

1. Hose combination (100) with electromagnetic shielding, comprising: a radially inner hose (104) and a radially outer hose (102), wherein the radially inner hose (104) has at least one electrically conductive layer (106), wherein the radially inner hose (104) is loosely or detachably received in the radially outer hose (102) in such a way that it readily detaches from the radially outer hose when bent, and wherein the radially outer hose (102) is formed by a braided, knitted, woven or warp-knitted fabric, preferably formed from plastic fibers, or wherein the radially outer hose (102) comprises an extruded corrugated plastic tube, wherein the radially inner hose (104) comprising the at least one electrically conductive layer (106) is formed from a flat material (112) by folding, and wherein the two lateral edges (112a, 112b) of the flat material (112) are arranged to overlap one another, characterised in that a predetermined circumferential section (104a, 104b) of the radially inner hose (104) is folded over onto or folded into the remaining circumferential section.

2. Hose combination according to claim 1, characterised in that at least the radially inner hose (104) has the at least one electrically conductive layer (106).

3. Hose combination according to claim 1 or 2, characterised in that the electrically conductive layer (106) is made of a material whose specific conductivity at a temperature of about 25°C is at least 30 MS / m.

4. Hose combination according to any one of claims 1 to 3, characterised in that the thickness (d1) of the electrically conductive layer (106) is at least 20 µm.

5. Hose combination according to any one of claims 1 to 4, characterised in that the electrically conductive layer (106) is connected to a stabilising layer (108), wherein the stabilising layer (108) is, for example, laminated onto the electrically conductive layer (106) or formed as a carrier layer.

6. Hose combination according to claim 5, characterised in that the stabilising layer (108) is arranged radially outside the electrically conductive layer (106).

7. Hose combination according to claim 5 or 6, characterised in that the ratio (d1 / d2) of the radial thickness (d1) of the electrically conductive layer (106) to the radial thickness (d2) of the stabilising layer (108) is between about 0.75 and about 1.25.

8. Hose combination according to any one of claims 1 to 7, characterised in that one of the lateral edges (112a, 112b) of the flat material (112) is folded back.

9. Hose combination according to any one of claims 1 to 8, characterised in that the radially outer hose (102) is formed in several layers.

10. Use of a hose combination (100) according to any one of claims 1 to 9 for protecting electrical lines from the influence of electromagnetic interference sources and / or for shielding current-carrying conductors, in particular in engine compartments of motor vehicles.