EP1077451A2 - Electrical cable or electrical line with a braided shield - Google Patents

Abstract

The cable or lead has a core consisting of electrical conductors and insulation and an electrically conducting screen with a mesh (GE) of groups of wires (FRE1-FRE12) wound in opposite directions with equal pitch angle and an enveloping cable sleeve. The number of first groups of wires (DR11-DR91;DL1-DL91) in one winding direction in the screen mesh is greater than in the opposite direction.

Description

The invention relates to an electrical cable or an electrical Line with one of dielectric conductors and insulation existing core and an applied over it electrically conductive shield made of a braid, its in opposite directions Spiral directions summarized in specializations Wires under the same but opposite directions Helix angles are coiled, as well as with a surrounding one Cable sheath.

For shielding electrical cables or electrical Lines are generally braids made of electrically conductive Wires used in opposite spiral directions the core of a cable or a line is applied, the structure of the braid is symmetrical. there the wires alternate in opposite directions above or below one another led, with the smallest possible area coverage should come about. However, this has the consequence that at such a construction with high torsion or bending Material wear, i.e. high abrasion on the individual wires occurs. However, this wear also turns up with regard to the shielding, a reduction in the shielding effect on. Such electrical cables or electric lines are for example from the German published application DE 24 43 973 known in which a screen made of metal wires or metal strips are applied to the core.

From German publication 1 640 958 there is an electrical one Insulated wire known, in which the metallic Shielding from a between insulation and sheath of the cable arranged, gap-forming braid consists of wires.

The present invention is based on the object to create electrical cable or an electrical line where possible material wear on the shield is excluded, whereby the design guarantees constant shielding values under torsion and bending stress are and still a highly flexible torsion and bending behavior is guaranteed. The task is with a cable or an electrical line of the above Art solved in that the number of braids the first folds wound in one direction with the wires running parallel in it is larger than the number of coils wound in the opposite direction Sockets with the wires running in parallel.

When designing the shield for cables or electrical Lines according to the invention are now several in technical terms summarized electrically conductive wires as closely as possible and running parallel under one for good flexibility especially suitable and adapted pitch angle on the core the cable or the line coiled. In this way a particularly high area coverage can now be achieved. However, the torsional behavior of this shield would not be satisfactory; because torsion in one direction would be too an unacceptable necking during a torsion in the opposite direction to an uncontrolled one Would loosen the wrapping. For this reason in the prior art used a braid that includes the same number of wires in each spiral direction and at which the change of performance and underpass, i.e. the change of location, each includes only one subject. This leads to significant mechanical wear, as already described above has been. In the construction according to the invention Problem of wear solved in that in a spiral direction essentially those used for shielding in several Folds summarized wires wound tightly are few while in the opposite direction wires grouped into compartments are applied, wherein in addition, the cycle of changing the up and down of the individual Fachungs extends over several crossing points. This ensures that the torsion and Bending behavior or the line is significantly improved. This arrangement of the wires according to the invention in this braid construction causes the torsional and flexural strength almost a single-layer wire wrapping (all Wires running in one direction) is given, however mechanical stability and electromagnetic The shielding effect is almost the same as with a normal braid stay. It is also advantageous that the mutual abrasion of the individual wires and thereby the destruction in a row significantly reduced by reducing the number of braiding changes becomes.

Figur 1 zeigt eine prinzipielle Darstellung eines in mehreren Fachungen ausgeführten Geflechtes.

Figur 2 zeigt den Ausschnitt eines Normalgeflechtes.

Figur 3 zeigt ein Ausführungsbeispiel nach der Erfindung.

The invention will now be explained in more detail with reference to three figures, the prior art being shown in FIGS. 1 and 2 in order to emphasize the difference from the exemplary embodiment of the invention shown in FIG.

Figure 1 shows a basic representation of a braid executed in several folds.

Figure 2 shows the section of a normal braid.

Figure 3 shows an embodiment according to the invention.

Figure 1 shows a cable K in cross section with a cable core KK and an applied braid that consists of two opposing Layers each with several - here 7 - folds FL11 to F17 or F21 to F27 is formed. So are the spiral directions the one running in parallel in the individual disciplines Wires D in one layer run counter to those in the second Location, so that a network through up and underpass of the individual folds formed in the crossing points becomes. In general, standard braids with 2x6, 2x8, 2x12 or 2x18 folds used. Figure 1 shows as Example of a braid structure with 2x7-folds, each Fachung 5 wires D includes.

As can now be seen from FIG. 2, the common Braids GN at every intersection KPN too a change of position or braiding between the right-handers Fachungen FR and the left-handed Fachungen FL take place, see above that mechanically there is a very strict coupling. The disadvantage, however, is that the torsion and bending ability is inhibited, and that this also means strong mechanical Set signs of wear, through which the goodness the shielding is reduced over time. Also revealed the constant change of positions increases openings, so that the degree of coverage by the screen and thereby the shielding values are impaired. The representation this figure 2 is greatly simplified and merely indicates that in the individual compartments FR and FL several wires DR or DL are included running in parallel.

Figure 3 now shows the structure of a mesh GE according to the Invention in which high flexibility, high area coverage and good torsion and bending properties are guaranteed. So are in one direction - here, for example, in the right turn - several specializations - here 12 specializations FRE1 to FRE12 - running in parallel under a suitable one Helix angle of preferably 45 ° applied, each Sizing FRE1 to FRE12 for example 9 individual wires - e.g. DR11 to DR91 in the subject FRE1 - contains. In the opposite However, the direction of the spiral is the number of Folds much lower; here are e.g. only two Sockets FLE1 and FLE2, each with several individual wires arranged so that a much larger distance between given the parallel courses FLE1 and FLE2 is. This leads to a mechanically loose, but electromechanical much denser mesh form, which makes the Shielding values can be improved. Because of this loose network but also the torsion and bending ability improved, since there is no longer such a close mechanical connection is given, as with braids according to the state of the Technology. In addition, the opposite folds also a change of location instead, so that thereby also the mechanical wear on the individual wires is reduced. The structure of this network according to the invention thus fulfills all the requirements underlying the task, so that the training Also suitable for special applications where high Shielding quality and flexible properties required like this e.g. for bus signal lines with high frequencies and high transmission rates must be the case. In addition is beneficial if the shield is still through a flexible nonwoven film spun onto the core was added is, this nonwoven film consisting of plastic threads is preferably metallized, e.g. with aluminum. About that the braid described above is then applied, in which preferably tinned copper wires are used.

Claims (7)

Electrical cable or electrical line with a core consisting of electrical conductors and insulation and an electrically conductive shield made of a braid applied thereon, the wires of which, in opposite spiral directions, are wound up in compartments at the same, but oppositely directed pitch angles, and with a surrounding cable sheath,
characterized,
that with the braid (GE), the number of the first sheaves (FRE1 to FRE12) wound in the one spiral direction with the wires running parallel therein (DR11 to DR91) is greater than the number of the second sheaves (FLE1, FLE2 ) with the parallel wires (DL11 to DL91). An electrical cable or line according to claim 1,
characterized,
that a metallized, preferably aluminum-coated, nonwoven film is spun between the core (KK) and the braid (GE). Electrical cable or electrical line according to one of the preceding claims,
characterized,
that tinned copper wires are used as wires (DR .., DL ..) in the individual compartments (FRE .., FLE ..). Electrical cable or electrical line according to one of the preceding claims,
characterized,
that the change of position of the second folds (FL ..) extends over two or more crossing points. Electrical cable or electrical line according to one of the preceding claims,
characterized,
that twelve folds (FRE1 to FRE12) run in one spiral direction and two folds (FLE1, FLE2) run in the opposite spiral direction. Electrical cable or electrical line according to one of the preceding claims,
characterized,
that in each subject (FR .., FL ..) there is more than one wire (DR .., DL ..); preferably run nine wires. Electrical cable or electrical line according to one of the preceding claims,
characterized,
that the wires (DR .., DL ..) are wound at a pitch angle of preferably 45 °.

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