DATA CABLE AND METHOD FOR PRODUCING SUCH A DATA CABLE

Abstract

A data cable has a specially arranged and embodied shielding foil. The shielding foil surrounds an insulated conductor and has multiple layers, including a conductive layer and at least one carrier layer on which the conductive layer is applied. The shielding foil is folded and has a fold around which the conductive layer is guided so that the conductive layer forms an upper face and a lower face. The shielding foil is wound around the insulated conductor. The shielding foil has multiple sequential windings that overlap in an overlap region in which the upper face in one of the multiple sequential windings makes contact with the lower face of a following one of the multiple sequential windings so as to form a continuous shielding configuration.

Claims

1. A data cable, comprising: at least one insulated conductor; and a shielding foil surrounding said insulated conductor and having multiple layers, including a conductive layer and at least one carrier layer on which said conductive layer is applied, said shielding foil being folded and having a fold around which said conductive layer being guided so that said conductive layer forms an upper face and a lower face, said shielding foil being wound around said insulated conductor, and said shielding foil having multiple sequential windings that overlap in an overlap region in which said upper face in one of said multiple sequential windings makes contact with said lower face of a following one of said multiple sequential windings so as to form a continuous shielding configuration.

2. The data cable according to claim 1, wherein said conductive layer is an outermost layer of said shielding foil.

3. The data cable according to claim 1, wherein said shielding foil is folded in a middle.

4. The data cable according to claim 1, wherein said carrier layer has an entire width and said conductive layer extends over said entire width.

5. The data cable according to claim 1, wherein said carrier layer has an entire width and said conductive layer extends over less than said entire width and more than half of said entire width.

6. The data cable according to claim 1, wherein said conductive layer extends completely over one of said upper and lower faces and on the other one of said upper and lower faces only in said overlap region.

7. The data cable according to claim 1, wherein said shielding foil is folded such that said carrier layer lies within said conductive layer.

8. The data cable according to claim 1, further comprising a wire shield disposed around said shielded foil and making contact with said conductive layer.

9. The data cable according to claim 1, wherein: the data cable is a coaxial cable; and said conductor is an inner conductor and said continuous shielding configuration is an outer conductor.

10. The data cable according to claim 1, wherein: the data cable contains multiple wires; and said shielded foil is wound around said wires so as to form a shielded wire bunch.

11. The data cable according to claim 1, wherein said conductive layer is an outermost layer; wherein said shielding foil is wound directly around said insulated conductor; and further comprising a wire shield directly surrounding said shielding foil.

12. The data cable according to claim 8, wherein said wire shield is a braided shield or a spiral wire shield.

13. The data cable according to claim 1, wherein the data cable contains exactly one wire pair having two wires.

14. The data cable according to claim 1, wherein the data cable is configured for use in high speed data transmission.

15. A method for producing a data cable, which comprises the steps of: surrounding at least one insulated conductor with a shielding foil that is embodied from multiple layers including a conductive layer and at least one carrier layer to which the conductive layer is applied, the surrounding step including the following substeps: folding the shielding foil which forms a fold around which the conductive layer is guided so that an upper face and a lower face of the conductive layer are defined; winding the shielding foil around the insulated conductor; and forming multiple sequential windings of the shielding foil that overlap in an overlap region in which the upper face in one of the sequential windings makes contact with the lower face of a following one of the sequential windings so that a continuous shielding configuration is formed.

16. The method according to claim 15, which further comprises guiding the fold of the shielding foil over a roller and compressing the fold.

17. The method according to claim 15, which further comprises performing the folding step and the winding step in separate steps.

18. The method according to claim 15, which further comprises folding the shielded foil during the winding step.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0037] FIGS. 1 to 3 are diagrammatic, sectional views of an exemplary embodiment of a data cable along a longitudinal direction according to the invention; and

[0038] FIG. 4 is a cross-sectional view of the data cable in a transverse direction with respect to the longitudinal direction.

DETAILED DESCRIPTION OF THE INVENTION

[0039] Referring now to the figures of the drawings in detail and first, particularly to FIGS. 1-3 thereof, there is shown in each case a sectional view of an exemplary embodiment of a data cable 2 along a longitudinal direction L thereof. FIG. 4 illustrates a cross-sectional view of the data cable 2 in a transverse direction with respect to the longitudinal direction L. In the case of the data cable 2, in general a folded shielding foil 4 is wound around an insulated conductor 6 in order to form a continuous shielding arrangement.

[0040] In the exemplary embodiments illustrated in FIGS. 1 to 3, the data cable is embodied as a coaxial cable for use in high speed data transmission, wherein the conductor 6 is an inner conductor that is surrounded by an insulation 8 that is used as a dielectric. The shielding foil 4 that is used in the exemplary embodiment as an outer conductor of the coaxial cable is wound directly around the dielectric. In addition, the shielding foil 4 is surrounded by a braided shield 10 around which an outer cover 12 of the data cable 2 is arranged. The braided shield 10 is in this case a wire braid and the outer cover 12 is produced from an insulating material. In an alternative, not illustrated, a spiral wire shield or in general a wire shield is arranged in lieu of the braided shield 10.

[0041] Particular importance is awarded to the special arrangement and embodiment of the shielding foil 4 that is illustrated in the three FIGS. 1 to 3 in three different variants. Differences arise in this case essentially in the type of fold produced and the precise embodiment of the shielding foil 4, as explained hereinunder.

[0042] In FIG. 1, the shielding foil 4 is a once-laminated foil that contains an insulating layer 14 and a conductive layer 16 that is applied thereto. The insulating layer 14 is embodied from an insulating material, preferably a synthetic material, and the conductive layer 16 is embodied from a conductive material, preferably from a metal. The shielding foil 4 is then in particular a metal-laminated synthetic material film. As a result of the folding procedure, a fold 18 is produced around which the conductive layer 16 is guided. In FIG. 1, the fold 18 is formed at half the entire width G of the shielding foil 4. As a consequence, a shielding foil 4 that is folded in the middle is produced, on which two layers 20, 22 are formed, the layers lying one on top of the other, namely an upper also outer layer 20 that is facing away from the conductor 6, and a lower also inner layer 22 that is facing towards the conductor 6. As a result of the middle fold, the layers 20, 22 contain in each case a width B1, B2 that corresponds to half the entire width G. By virtue of the middle fold, the shielding foil 4 is particularly simple to process and during the winding procedure produces a particularly uniform shielding arrangement.

[0043] An essential aspect that is achieved in all exemplary embodiments is the continuous shielding arrangement as a result of folding the shielding foil 4 in combination with the winding arrangement in lieu of the longitudinal fold. By virtue of the winding arrangement, multiple windings 24 are formed in the longitudinal direction L, wherein two sequential windings 24 overlap in the overlap region 26. In order to combine the mechanical flexibility of a wound shielding foil 4 with the advantageous electrical characteristics of a longitudinally folded shielding foil 4, the conductive layer 16 now contacts itself in the overlap region 26. This is achieved by virtue of the special folding arrangement in which the conductive layer 16 is guided around the fold 18 and is guided from the lower layer 22 into the upper layer 20. The conductive layer 16 thus contains an upper face 28 and a lower face 30. Where contact is made in overlapping windings, the upper face 28 of the conductive layer 16 makes contact in one of the windings 24 with the lower face 30 of the same conductive layer 16 in the following winding 24, and in fact exactly in the overlap region 26. As a consequence, eddy currents can dissipate in the longitudinal direction L even in the case of the wound shielding foil 4, as in the case of a longitudinally folded shielding foil 4 but now in an advantageous manner in combination with the improved mechanical flexibility of the wound arrangement.

[0044] In FIG. 1, the conductive layer 16 is formed over the total entire width G so that the folded insulating layer 14 is surrounded and encompassed by the conductive layer 16. As a consequence, the insulating layer 14 is shielded from the primary electrical field of the conductor 6 and contributes at the most in an insignificant manner to its transmission characteristics. Moreover, the conductive layer 16 is directly contacted by the braided shield 10. As a result of the folded embodiment, the amount of frictional wear on the conductive layer 16 of the upper layer 20 caused by the braided shield 10 is not critical since a continuous and effective shielding arrangement is still ensured by virtue of the conductive layer 16 in the lower layer 22.

[0045] FIG. 2 illustrates a variant of the data cable 2, wherein the upper face 28 of the conductive layer 16 contains a width B1 that is reduced in comparison to the example in FIG. 1. The conductive layer 16 is thus applied only in part over the entire width G to the insulating layer 14 but is applied to more than half the entire width G so that in the overlap region 26 it is ensured that overlapping windings can make contact in the conductive layer 16. FIG. 2 illustrates the upper face 28 exactly on the overlap region 26 so that the wound shielding foil 4 is insulated towards the outside and the conductive layer 16 is not contacted by the braided shield 10. In an alternative, not illustrated, the braided shield 10 is omitted. Fundamentally, as an alternative, it is also feasible to reverse the arrangement in such a manner that the conductive layer 16 faces outwards and the insulating layer 16 lies inwards on the insulation 8.

[0046] In the case of the variant illustrated in FIG. 3, a shielding foil 4 that is modified in two respects is used. On the one hand, the shielded foil 4 is laminated twice, in other words a conductive layer 16 is applied in each case to both sides of an individual insulating layer 14, wherein these two conductive layers 16 are not automatically connected to one another and also not automatically connected in an electrical manner to one another. On the other hand, the shielding foil 4 is not folded in the middle but merely folded in such a manner that one of the layers 20, 22, in this case the upper layer 20, is exactly as wide as the overlap region 26.

[0047] In all the illustrated exemplary embodiments, the conductive layer 16 is an outermost layer of the folded shielded foil 4, in other words the shielded foil is folded in such a manner that the conductive layer 16 faces outwards and the insulating layer 14 wraps around at least in part.

[0048] The different concepts that are described above with reference to exemplary embodiments with respect to the shielding foil 4, in other words in particular the widths B1, B2 of the layers 20, 22, the position of the fold 18, the in part or complete embodiment of the conductive layer 16, the arrangement and number of the layers and their orientation inwards or outwards are not limited to the three illustrated variants but rather can also be combined with one another in order to obtain further advantageous embodiments. It is thus possible, for example in FIGS. 1 and 2, to also use a double-laminated shielding foil 4 that contains two conductive layers 16.

[0049] In addition, the special embodiment and arrangement of the shielding foil 4 is not limited to use as an outer conductor in a coaxial cable. By way of example, FIG. 4 illustrates in a sectional view in a transverse manner with respect to the longitudinal direction L a data cable 2 that is embodied as a shielded wire pair having two wires 32 that are surrounded jointly by the folded shielding foil 4. The wires 32 can be either twisted around one another or alternatively guided in parallel with one another and not twisted. Variants that comprise more than two wires are also feasible.