Method for manufacturing a cable with a shield

Abstract

The present invention relates to a method for manufacturing a cable (1) with a shield (2), wherein the cable (1) has a core (4) with at least one inner conductor (5) and a shield (2) arranged around the core (4), wherein the core (4) is provided first. The method is characterized in that, to manufacture the shield (2), in a first step, a first conductor (3) is wound around the core (4), and subsequently, in a second step, at least a second conductor (3) is wound around the core (4).

Description

The present invention relates to a method for producing a cable having a shield, wherein the cable has a core having at least one inner conductor and a shield arranged around the core, wherein the core is first provided.It is known that electrical cables are used in a wide variety of applications and are often sensitive to external electromagnetic influences. A signal transmission or the conduction of electric current takes place in this case in one or more inner conductors which are arranged in the core of the cable, the so-called core. The core also typically comprises an insulator of non-conductive material. The inner conductors can also be individually insulated. In order to ensure the integrity of the signal transmission and to reduce or eliminate interference from external electromagnetic fields, cables are often provided with a shield. This shielding may also help minimize the electromagnetic radiation generated by the cable itself, so as to prevent interference with other nearby electronic devices or systems. As is known, the shielding is realized by a layer of conductive material which is designed in the form of a foil or a wire or a plurality of wires. The shield is usually arranged coaxially to the core and in particular on the insulation of the core.The shield in the form of a plurality of wires may be braided around the cable core, for example. In the manufacture of this type of shielding, slow-acting braiding machines are used. Braid shielding remains relatively stable during cable separation during subsequent cutting, but braid shielding may interfere with cable flexibility.Alternatively, a twist or helical shield may be provided in which one or more wires are wound over the entire surface of the core. In order to achieve the desired coverage, the production speeds are also rather low here. A cable with a twist shield tends to be more flexible than a cable with a braid shield. However, it is disadvantageous that the swirl screen easily fiberizes when the cable is cut to size and can only be connected with difficulty, for example, to connectors or other components.It is therefore an object of the present invention to propose an improved manufacturing method for a cable with a shield. In particular, a production speed is to be improved and the disadvantages of the known shields are to be eliminated.The object is achieved by a method having the features of the independent claim.In the method according to the invention for producing a cable having a shield, in which the cable has a core having at least one inner conductor and a shield arranged around the core, the core is first provided. The method is characterized in that, in order to produce the shielding, in a first working step, a first conductor is initially wound around the core and subsequently, in a second working step, at least one second conductor is wound around the core. By dividing the covering of the core with the conductors into several steps, each individual conductor can be wound around the core with a higher lay length, in contrast to the known swirl shields. The cable can thus be guided through the corresponding machine at a higher speed. The individual steps can be carried out, for example, with a plurality of series-connected machines, which results overall in a substantially higher production speed. In this case, the lay length for the conductors can be selected, for example, in accordance with the desired coverage of the core and thus the desired shielding properties. The individual conductors can stabilize each other, thus avoiding the excessive fiberization of the insulation during the cutting of the cable.The core of the cable may be provided by any known method. For example, a plurality of inner conductors are stranded by a stranding machine and are coated with a plastic insulation. However, an individual inner conductor can also be provided with a shield by the method according to the invention. The cable thus produced can then be stranded into a cable having a plurality of conductors.It is also very advantageous if, in a third working step following the second working step, a third conductor is wound around the core and, if appropriate, further working steps of this type follow further conductors. In this way, the construction of the shielding can be distributed over any number of working steps. The aim is, after a certain number of working steps, to achieve a shielding with certain desired properties, such as, for example, a desired surface covering of the core or a desired layer thickness. Each further conductor can stabilize the previous conductors, for example by crossing the previous conductors or at least partially being placed over the previous conductors. Thus, a possible fiberization of the shield during the later cutting of the cable is further reduced. In addition, the shielding thereby becomes more resistant to damage, for example when the cable is moved.It is likewise advantageous if the first conductor, the second conductor and, if appropriate, the further conductors each comprise one or more individual wires. The number of individual wires can influence the flexibility of the cable produced, the shielding properties of the shielding and the necessary number of working steps in the production of the cable. When a plurality of individual wires are used, high-frequency signals, for example, can be shielded better. In the present production method, a similar shielding can possibly be produced when using bundles of individual wires with few working steps as when using individual wires in many individual steps. The balance required here depends on the desired production speed and the desired properties of the shielding.It is also very advantageous if a number of individual wires in the first, second and optionally further conductors are different. This allows screens with very individual properties to be produced. Certain areas of the cable may be provided with a stronger shield in this way. The flexibility of the cable can also be influenced by the number of individual wires. The strength of the shield can also be specifically influenced in this way, in order, for example, to further reduce the already repeatedly mentioned fibrousing of the shield during the cutting of the cable.It is likewise advantageous if the first conductor is wound around the core in a first rotational direction in the first working step and the second conductor is wound around the core in a second rotational direction in the second working step, wherein in subsequent further working steps, in particular, the first rotational direction and the second rotational direction are alternated. In this way, the first conductor is stabilized by the second conductor. Accordingly, all the conductors wound in the former processes are stabilized by the conductors wound in the latter processes. In this way, a strong and stable shielding is produced which, depending on the number of individual working steps, has similar properties to a braid shielding. The first direction of rotation can run clockwise, for example, in a plan view of the cable cross section, and the second direction of rotation can run counter-clockwise or vice versa.It is particularly advantageous if a lay length of the first, second and / or optionally of the further conductors is different. This allows individual patterns of shielding to be created. By targeted manipulation of the lay length, a cable can be created which has regions of different properties with regard to flexibility and shielding along its length. For cables which are moved repeatedly at similar locations in robots, for example, this can be an advantage. These locations can be designed to be more flexible in a targeted manner, for example, by manipulating the lay length and / or the number of individual wires in the respective conductor.It is advantageous if the first working step is carried out by a first winding device, the second working step is carried out by a second winding device and further working steps are optionally carried out by further winding devices. As already described, the method according to the invention can be carried out particularly efficiently if the individual working steps are carried out by machines arranged one behind the other. This allows the core to be passed through the individual winding devices at high speed and the shield to be built up step by step. The individual winding devices here operate, for example, spatially one behind the other but in parallel over time. The term winding device has been chosen here for the purpose of winding a conductor around the core. The winding devices can also be designed as stranding machines or in a similar manner to stranding machines.In this context, it is particularly advantageous if the first winding device, the second winding device and / or the further winding devices comprise the following:a rotatably mounted receiving device for a reel,a striker for pulling a conductor from the coil, the striker being rotatably mounted such that it encircles the coil for pulling the conductor,a frame on which the receiving device and the striker are arranged, wherein the frame comprises a first frame part and a second frame part, whereinthe winding device has a passage for passing the core and / or the conductor through the winding device, which passage is arranged concentrically with a common rotational axis of the receiving device and the striker, wherein the passage has a plurality of separate guide regions for the core and the conductor, and / orthe receiving device is arranged between the first frame part and the second frame part, wherein the first frame part and / or the second frame part are configured to be movable axially along the frame.Such a winding device is described in the German patent application with the file reference 10 2022 134 610.2, unpublished at the filing date, under the term unwinding device. It has been found that this machine, due to its high speed of operation and high modularity, is particularly suitable for producing a cable with a shield according to the present method. In particular, it is possible with comparatively little space outlay to operate a plurality of such machines coaxially one behind the other. This is achieved, for example, by the passage described, through which the core is passed in each case. For this purpose, in particular one of the guide regions can lie exactly centrally on the common axis of rotation. Further guide regions can be arranged concentrically around the axis of rotation with the same radius. The conductor on the coil can comprise one or more individual wires, as already described.The movable frame parts allow the spool to be changed quickly and easily, as a result of which the winding device has a high efficiency with low downtime. In particular, this is made possible by a relative movement between the first frame part and the second frame part. On the other hand, the winding device can be adapted to coils of different widths. Depending on the distance of the striker bar from the receiving device, coils of different diameters can also be used in the winding device. The receiving device is in particular designed as a shaft, onto which a coil can be plugged and with which the coil can be braced for transmitting a torque. During the axial movement of a frame part, in particular, a relative movement between the receiving device and at least one of the frame parts likewise takes place. In this context, the axial direction is a direction substantially parallel to the common axis of rotation of the receiving device of the striker bar.The striker comprises, for example, a roller which serves for deflecting the conductors after the removal from a reel. When the device is used as intended, the roller is arranged, for example, substantially centrally with respect to the receiving device. The striker bar, when used as intended, in particular engages around the coil to be wound, wherein a part of the striker bar serves for deflecting the conductors. A further part of the striker can comprise a counterweight, which avoids uneven centrifugal forces or imbalance of the striker. The striker is often also referred to in technical usage by the English term flyer.If the winding device is formed with the passage, the conductors are laid around the core only at one end of the passage, for example. The construction of the shielding in the individual working steps is then in particular carried out similarly to stranding, wherein the passage with the separate guide regions behaves similarly to a stranding disc.It is also advantageous if the receiving device is hollow, wherein the passage leads through the receiving device. As a result, the conductor can be guided close to the axis of rotation of the receiving device and of the striker bar. On the one hand, this prevents unnecessary stresses on the conductors due to additional deflections. On the other hand, a plurality of winding devices arranged one behind the other, as already described above, can be arranged in a space-saving manner at least in terms of width. Also, a reverse rotation of the conductors can be more easily achieved by a guide close to the axis of rotation, whereby a shielding without torsional stresses is produced. The conductors guided by the receiving device in the separate guide regions are rotated about the axis of rotation of the coil in particular at the speed of rotation of the coil.It is also very advantageous if at least a subset of the guide regions is arranged radially spaced apart from the common axis of rotation. For example, a guide region is arranged exactly on the common axis of rotation, through which the core is guided. At least one further guide region is arranged radially spaced apart. The conductor is passed through the latter and wound around the core at the latest at one end of the passage.It is also advantageous if the receiving device is connected axially fixedly to the first frame part or the second frame part. A fixed bearing point is simpler to construct and gives the receiving device increased stability. During the change of the package, the package can be removed at the free end of the receiving device opposite the fixed bearing point. In particular, the receiving device is firmly connected to the first frame part, wherein the second frame part is designed to be axially movable. Of course, the receiving device can likewise be fixedly connected to the second frame part, wherein the first frame part is designed to be axially movable.It is also very advantageous if the receiving device is connected to a first drive for rotating the receiving device. The receiving device can thus be driven by a separate drive of the winding device. A spool which is to be unwound from the winding device is connected in a torque-transmitting manner to the receiving device and is likewise set in rotation by the rotation of the receiving device. An individual speed or speed of the receiving device can be set, for example, depending on the mass and the winding state of the received coil. The drive can be designed in particular as an electric motor. The receiving device can be connected to the drive, for example, via a belt. In this case, it is conceivable to provide a transmission between the drive and the receiving device.It is advantageous if the striker comprises a braking device for a specific deceleration. The striker can be driven, for example, solely by the conductor drawn from the spool. In this case, the striker is not connected to a drive. The brake device nevertheless allows the striker to rotate at a well-defined rotational speed and be synchronized, for example, with other rotating components.It is particularly advantageous if the striker is connected to the first drive for rotating the striker during a winding process of the winding device. The receiving device and the striker can thus be driven by a common drive. In particular, the receiving device and the striker hereby run at the same speed during the unwinding operation. The striker and the receiving device are connected in particular to a torque-transmitting transmission element. This gear element can be designed, for example, to be releasable in the case of a movable first frame part and / or second frame part.It is also advantageous if the striker is connected to a second drive for rotating the striker. As a result, a rotation of the striker can take place completely independently of a rotation of the receiving element or of the spool. A torque-transmitting connection between the receiving element and the striker is not necessary in this case. The rotation of the receiving element and the striker can be controlled independently of each other. In particular, a rotation of the striker bar of a winding device can in this case be easily synchronized with the rotation of the striker bar of a further winding device. The rotation of the tuck-off bar can also be synchronized with the rotation of a stranding disk or with the rotation of a tuck-off bar of a winding device.Further advantages of the invention are described in the following exemplary embodiments. They show, in each case schematically: FIG. 1 shows a cable after working steps of the method according to the invention, in which in each case a single wire is wound around a core of the cable, FIG. 2 shows a cable after working steps of the method according to the invention, in which in each case a plurality of individual wires are wound around a core of the cable, FIG. 3 shows a winding device for carrying out the method in a side view, FIG. 4 shows a winding device for carrying out the method in a front view, and FIG. 5 shows a plurality of winding devices during the execution of the method.In the following description of the figures, the same reference numerals are used for features that are identical and / or at least comparable in each case in the different figures. The individual features, their configuration and / or mode of action are usually explained in detail only when first mentioned. If individual features are not explained in detail again, their configuration and / or mode of action corresponds to the configuration and mode of action of the features that already have the same effect or are similar to those already described.FIG. 1 shows a cable 1 after various working steps of the method according to the invention, in which a shield 2 of the cable 1 is gradually built up. In the cable sections shown below, a respective working step was carried out in which a conductor 3 was wound around a core 4 of the cable 1. The newly added conductor 3 is shown in each case in dashed lines. The only exception is the cut-out shown at the bottom, which shows the cable 1 with the finished shield 2.In the top illustration, in a first working step, a first conductor 3 was wound around the core 4 of the cable 1. Likewise indicated in this illustration is an inner conductor 5 of the core 4 of the cable 1. The first conductor 3 is wound around the core 4 with a specific lay length 6, wherein the lay length 6 indicates a distance along the cable 1 in which the conductor 3 once completely surrounds an outer surface of the core 4. The lay length 6 is the same for all conductors 3 in this example. As described above, however, it can also vary for the different conductors 3.In the illustration arranged underneath, a second conductor 3 was wound around the core 4 in a second working step. In the present case, each conductor 3 comprises, for example, exactly one single wire 7. In the two following representations, a third conductor 3 was wound around the core 4 in a third working step and a fourth conductor 3 was wound around the core in a fourth working step. The individual conductors 3 are displaced here, for example, along the cable 1 in order to gradually result in the complete possible covering of the core 4. As already described, the bottom view shows the completed shield 2 after further working steps.In the first working step, the first conductor 3 is wound around the core 4 in a first rotational direction and in the second working step, the second conductor 3 is wound around the core 4 in a second rotational direction. In the further working steps, the direction of rotation is in each case alternated. In this way, the conductors 3 are fixed and stabilized in each further working step. This results in a solid shielding 2 which has similar properties to a braid shielding, but can be produced much more quickly if the working steps are carried out locally offset as described above but parallel over time.FIG. 2 shows a further variant of the method in which, in a first working step in the upper illustration, a first conductor 3 has been wound around the core 4. In contrast to the previous example, the first conductor 3 here consists of five individual wires 7. The second conductor 3 also comprises five individual wires 7. the directions of rotation in which the conductors 3 were wound around the core 4 in the individual working steps differ, for example, as before. By a suitable selection of the number of individual wires 7 in the conductors 3 and the respective lay length 6, in this case even after two working steps a complete shielding 2 with the desired properties can be obtained.FIG. 3 shows a schematic side view of a winding device 8 which can be used for carrying out the method according to the invention. The conductor 3 is drawn off from a coil 9. The spool 9 is arranged on a rotatably mounted receiving device 10. For removing the conductor 3 from the coil 9, the unwinding device has a striker 11, wherein the striker 11 is mounted in such a way that it encircles the coil 9 for removing the conductor 3. The winding device 8 comprises a frame 12, on which the receiving device 10 and the striker 11 are arranged. The frame 12 in turn comprises a first frame part 13 and a second frame part 14. A passage 15 through the winding device 8 for passing through, for example, the core 4, is illustrated as dashed lines, which passage is arranged concentrically with respect to a common axis of rotation 16 of the receiving device 10 and of the striker 11.The passage 15 comprises a plurality of separate guide regions 17, for example for the conductor 3 and the core 4 (see FIG. 4 ). In this example, it is shown how the conductor 3 is guided from the coil 9 via the striker 11 to the passage 15. For this purpose, the striker 11 has a guide 18, which is also shown in dashed lines. The conductor 3 is then brought out of the winding device 8 close to the common axis of rotation 16 and then or directly wound around the core 4. In order to set the spool 9 in rotation, the winding device 8 comprises a first drive 19 for rotating the take-up device 10. In addition, in this example, the striker 11 is driven solely by the conductor 3 drawn from the spool 9. For a specific control of the rotation and in particular of the rotational speed, the striker 11 in this case comprises a brake device 21. In the present illustrations, a spool 9 with the maximum possible diameter is inserted into the winding device 8. However, smaller diameter coils 9 may of course also be used. Of course, the winding device 8 can also be designed for larger coil diameters by a different configuration of the striker 11.In this example, the receiving device 10 is arranged on the first frame part 13, wherein it is in particular axially fixedly connected to the first frame part 13. The striker 11 is arranged here on the second frame part 14. The receiving device 10 is arranged between the first frame part 13 and the second frame part 14, wherein the first frame part 13 and the second frame part 14 each have a bearing point 22 for the receiving device 10. The receiving device 10 is hollow and is in particular designed as a hollow shaft. The passage 15 passes through the receiving device 10. One or both of the frame members 13, 14 may be formed to be axially movable along the frame 12 to enable the spool 9 to be changed easily. Alternatively or additionally to the brake device 21, the striker 11 can also be connected to its own second drive 23. This allows an even more accurate setting and synchronization of the rotational speed of the striker 11.FIG. 4 shows a schematic front view of the winding device 8 from FIG. 3, the view of the passage 15 is additionally shown enlarged. The separate guide regions 17 of the passage 15 are clearly shown here. a larger guide region 17 is arranged exactly on the common axis of rotation 16 of the receiving device 10 and of the striker 11. However, a subset of the guide regions 17 is likewise arranged at a distance from the common axis of rotation 16. In the present case, guide regions 17 are arranged at different distances from the common axis of rotation 16. In principle, a guide region 17 spaced apart from the axis of rotation 16, into which the conductor 3 is introduced after being pulled off the coil 9, can be sufficient for the present application. The guide region 17 arranged on the axis of rotation 16 is suitable, for example, for guiding the core 4 through. By means of a plurality of guide regions 17, in principle at least a part of the shield 2 can be produced on a winding device 8 and stranding with further cables or cable components can be carried out.During operation of the winding device 8, the guide regions 17 arranged at a distance from the axis of rotation 16 rotate about the common axis of rotation 16 at the speed of rotation of the receiving device 10 and / or the speed of rotation of the striker 11.FIG. 5 shows three winding devices 8 arranged one behind the other, each of which carries out a working step of the method according to the invention. The core 4 of the cable 1 to be produced runs from right to left through the winding devices 8 in this case. the core 4 is guided in this case by one of the separate guide regions 17 of the passages 15 of the winding devices 8. After each winding device 8, a schematic enlargement of the core 4 is shown with the corresponding representations from FIG. 1. the first winding device 8 arranged on the right wraps around the core 4 with a first conductor 3 in a first working step. the centrally arranged second winding device 8 wraps around the core 4 with a second conductor 3 in a second working step. the third winding device 8 arranged on the left wraps around the core 4 with a third conductor 3 in a third working step.The working steps take place spatially offset. The winding devices 8 can however operate in parallel over time and thus achieve a high production speed. As before, the directions of rotation in which the conductors 3 are wound around the core 4 are alternated. In principle, any number of the winding devices 8 can be arranged one behind the other in order to produce a cable 1 with a desired shielding 2.The production speed can even tend to be increased with more winding devices 8 used, since each individual winding device 8 can then operate with a higher lay length 6.List of reference characters1 Cable 2 Shield 3 Conductor 4 Core 5 Inner conductor 6 Lay length 7 Single wire 8 Winding device 9 Coil 10 Receiving device 11 Striker 12 Frame 13 First frame part 14 Second frame part 15 Passage 16 Axis of rotation 17 Guide region 18 Guide 19 First drive 20 Belt 21 Braking device 22 Bearing point 23 Second drive

Claims

Method for producing a cable (1) having a shield (2), wherein the cable (1) has a core (4) having at least one inner conductor (5) and a shield (2) arranged around the core (4), wherein the core (4) is first provided, characterized in that, in order to produce the shield (2), in a first working step, a first conductor (3) is initially wound around the core (4) and subsequently, in a second working step, at least one second conductor (3) is wound around the core (4).Method according to the preceding claim, characterized in that, in a third working step following the second working step, a third conductor (3) is wound around the core (4) and, if appropriate, further working steps of this type with further conductors (3) follow.Method according to one of the preceding claims, characterized in that the first conductor (3), the second conductor (3) and optionally the further conductors (3) each comprise one or more individual wires (7).Method according to the preceding claim, characterized in that a number of individual wires (7) in the first, second and optionally further conductors (3) are different.Method according to one of the preceding claims, characterized in that the first conductor (3) is wound in a first rotational direction around the core (4) in the first working step and the second conductor (3) is wound in a second rotational direction around the core (4) in the second working step, wherein in subsequent further working steps, in particular, alternation is made between the first rotational direction and the second rotational direction.Method according to one of the preceding claims, characterized in that a lay length (6) of the first, second and / or optionally of the further conductors (3) is different.Method according to one of the preceding claims, characterized in that the first working step is carried out by a first winding device (8), the second working step is carried out by a second winding device (8) and further working steps are optionally carried out by further winding devices (8).Method according to the preceding claim, characterized in that the first winding device (8), the second winding device (8) and / or the further winding devices (8) comprise: - a rotatably mounted receiving device (10) for a coil (9), - a turn-off bracket (11) for pulling a conductor (3) from the coil (9), the turn-off bracket (11) being rotatably mounted in such a way that it encircles the coil (9) for pulling off the conductor (3), - a frame (12) on which the receiving device (10) and the turn-off bracket (11) are arranged, the frame (12) comprising a first frame part (13) and a second frame part (14), - the winding device (8) having a passage (15) for passing the core (4) and / or the conductor (3) through the winding device (8), which is arranged concentrically to a common axis of rotation (16) of the receiving device (10) and the striker bar (11), wherein the passage (15) has a plurality of separate guide regions (17) for the core (4) and the conductor (3), and / or - the receiving device (10) is arranged between the first frame part (13) and the second frame part (14), wherein the first frame part (13) and / or the second frame part (14) are configured to be movable axially along the frame (12).Method according to the preceding claim, characterized in that the receiving device (10) is of hollow design, the passage (15) leading through the receiving device (10).Method according to either of Claims 8 and 9, characterized in that at least a subset of the guide regions (17) is arranged at a radial distance from the common axis of rotation (16).Method according to one of Claims 8 to 10, characterized in that the receiving device (10) is connected axially fixedly to the first frame part (13) or the second frame part (14).Method according to one of Claims 8 to 11, characterized in that the receiving device (10) is connected to a first drive (19) for rotating the receiving device (10).Method according to one of Claims 8 to 12, characterized in that the striker (11) comprises a braking device (21) for a specific deceleration.Method according to one of Claims 8 to 13, characterized in that the striker (11) is connected to the first drive (19) for rotating the striker (11) during a winding process of the winding device (8).Method according to one of Claims 8 to 14, characterized in that the striker (11) is connected to a second drive (23) for rotating the striker (11).

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