EP3224838B1 - Cable comprising braided pairs of strands - Google Patents

Description

The invention relates to a cable with at least two wire pairs, each of which is set up to transmit a differential data signal. In particular, the invention relates to a USB cable such as a USB 3.0 cable or a USB 3.1 cable.

The transmission of USB signals is required for a wide variety of technical applications. For example, a USB socket for plugging in USB terminals may be desired in a rear part of a vehicle, so that a USB cable has to be led through the vehicle from the front to the rear. USB sockets or USB connections may also be required at different locations (offices, public facilities, means of transport, etc.) for connecting USB terminals, with USB cables having to be laid for this purpose.

Conventional USB2 interfaces (e.g. USB 2.0 interfaces) have only one signal wire pair (D + and D-) and one wire pair for power supply (GND, VBUS). The data is transmitted symmetrically via the signal wire pair, the data signal ("signal part") being transmitted through one wire of the signal wire pair and the respective inverted data signal ("reference part") being transmitted through the other wire. For this purpose, a cable for the transmission of USB2 signals has two twisted and shielded wires as a signal conductor pair in order to avoid transmission interference as far as possible. The signal receiver determines the differential voltage of the data signal differentially transmitted via the signal wire pair, so that interference acting on both wires of the signal wire pair is eliminated to the same extent.

The USB3 standard was introduced a few years ago. USB3 interfaces (e.g. USB3.0 interfaces) have at least two additional signal wire pairs (SSTX + and SSTX-; SSRX + and SSRX-) in addition to the connections explained above (D +, D-, GND, VBUS). A differential data signal is transmitted via each of these two signal wire pairs. Overall, this achieves higher data rates than with the conventional USB2 standard.

A conventional USB 3.0 cable is in Fig. 1 shown. Shown are three twisted pairs (112, 114, 116), each of which is set up to transmit a differential data signal. A ground conductor in the form of a drain wire 115 can each be provided adjacent to the twisted wire pairs. There are also two (not twisted) wires 122, 124 for power supply. The individual wire pairs are each surrounded by a foil shield, and all wires are surrounded by a common shield 130 and a protective sheath 150. In addition, filling elements 140 can be provided in order to ensure a cable that is round in section.

It has been found that with such a conventional wire arrangement, depending on the course and distance between the wire pairs in the cable, crosstalk of different strengths can occur between the individual wire pairs. Furthermore, a conventional USB 3.0 cable is comparatively thick, which makes simple and space-saving installation difficult.

From the WO 2013/033950 A1 and US 6,452,107 B1 cables with at least two pairs of wires for transmitting a differential data signal are known, the at least two pairs of wires running helically around a common stranding center in the longitudinal direction of the cable.

The US 2014/318859 A1 discloses a cable having a core wire, a first pair of differential wires and a second pair of differential wires. The cable also has six further wires, three of which are arranged on opposite sides of the core wire.

The JP 2008 016400 A describes a cable with a central arrangement and with four pairs of differential wires. The central arrangement has four wires and a spacer. The pairs of differential wires are arranged separately from one another by the spacer.

In view of the problems described, it is the object of the present invention to make a cable described at the beginning more compact and at the same time to ensure satisfactory protection against external interference and interference from adjacent wire pairs.

This object is achieved according to the invention by a cable according to claim 1. Advantageous further developments of the invention are described in the dependent claims.

In the case of a cable of the above-mentioned type, it is provided according to the invention that at least one further wire pair does not have its own shielding, the wires of the further wire pair being arranged at a distance from one another on opposite sides of the stranding center.

In the cable according to the invention, the at least two pairs of wires run in the longitudinal direction of the cable in a helical manner around a common stranding center. In other words, the individual wires of a wire pair are not twisted with one another, but rather the wire pairs are stranded with one another around a common stranding center. Furthermore, the mutual course of the individual wire pairs and the distance to the respectively adjacent wire pairs along the cable are predetermined by the stranding, so that a predictable, constant crosstalk strength per unit cable length can be expected. Incidentally, due to the orderly course of the individual wire pairs around the stranding center, the cable can be designed to be more compact and thus also thinner and more space-saving than conventional cables, whereby the installation effort and the transport costs can be reduced.

According to the invention, at least two pairs of wires in the cable, in the case of a USB-3 cable, the two super-speed pairs, have their own shielding, but at least one The third wire pair of the cable, in the case of a USB-3 cable, the high-speed pair D +, D-, does not have its own shielding. In this case, it is provided according to the invention that the wires of the third wire pair in the cable are arranged at a great distance from one another on opposite sides of the stranding center. The two wires of the third wire pair are arranged adjacent to the common shield ("sum shield") that runs around all wire pairs, so that maximum coupling of these wires to the grounded sum shield is ensured. One can speak of a "quasi-mass-related transmission" via the third pair of wires, with good decoupling from the live wire running centrally in the cable. The electric field emanating from the wires of the third wire pair is oriented towards the nearby summation shield, but not in the direction of the middle of the cable in which the current-carrying wire runs.

Compared to conventional cables with comparable inner conductor or core cross-sections such as a USB 3.x cable, as shown in Fig. 1 is shown, a reduction in the cable diameter by about 20% to about 40%, in particular by about 30%, is possible through the arrangement of the wire pairs according to the invention. Conventional USB-3 cables with comparable wire cross-sections have a cable diameter between 7 mm and 8 mm. In contrast, a USB-3 cable according to the invention has a cable diameter between 5 and 6 mm, in particular approximately 5.5 mm.

The cable according to the invention preferably has exactly three wire pairs running helically around the common stranding center. If the cable is a USB 3.x cable, the three wire pairs represent the wire pairs SSTX + and SSTX- described at the beginning; SSRX + and SSRX-; D + and D- represent. Alternatively, four or more wire pairs, each set up for the transmission of a differential signal, are also possible.

With regard to a particularly compact design of the cable, it has proven to be advantageous that the common stranding center has a further wire preferably running in the middle of the cable, in particular the current-carrying wire (VBUS) of the USB cable. By a stranding center running along the middle of the cable in the form of another wire, which is helical from the wire pairs is circulated, a desired roundness of the cable can also be ensured in a simple manner without numerous filling elements are required.

The further wire preferably has a conductor with a larger cross-sectional area than the conductors of the differential wire pairs. In this way, on the one hand, the manufacture of the stranding around the further core can be simplified. For example, the further wire can have a larger cross-sectional area the more wire pairs are to be stranded around it. Furthermore, higher currents or higher electrical powers can be transmitted via a core with a larger conductor cross-section. The conductor diameter of the individual wires of the wire pairs are preferably less than half as large as the conductor diameter of the other wire.

With regard to possibly required high currents of 2 A and more, which are required, for example, for fast charging of mobile devices via the USB port, it has proven to be useful that the cross-sectional area of the conductor of the further wire is greater than 0, 5 mm ² and smaller than 1.5 mm ² , in particular about 0.75 mm ² . Particularly when the cable according to the invention is used in the automotive sector, it is possible in this case to dispense with laying further power cables in addition to the USB cable, since high electrical powers can already be transmitted via the cable according to the invention.

The conductor of the further wire preferably has ten or more, in particular 15 or more copper wires, each with a diameter of less than 0.5 mm, in particular less than 0.25 mm. The insulation of the further wire can consist of a "bad" material from an HF-technical point of view, that is to say of a material with a high loss factor or high attenuation. For example, the insulation of the further wire is a PVC insulation. In this way, the propagation of interference within the cable, which, for example, can lead to increased coupling of the SSTX / SSRX wire pairs to one another, can also be attenuated.

USB cables regularly have a shield, for example in the form of a braided shield. In the case of the cable according to the invention, too, such a common screen is provided which encircles all wire pairs. This shield is grounded and particularly preferably forms the ground conductor (GND) of the cable. This means that the at conventional USB cables in the form of a further wire existing ground conductor (reference number 124 in Fig. 1 ) in the cable can be omitted. In other words, the screen, which is already present, forms the ground conductor, as a result of which the compactness of the cable can be further improved while at the same time maintaining the screening effect. In particular, it is possible in this case to design the stranding center in the form of a single wire, namely the current-carrying wire of the USB cable, which makes the production of the stranded cable easier, since there are no other interfering wires.

With regard to an effective suppression of external disturbances, it has proven to be expedient that the lay length of the helical course of the individual wire pairs is greater than 40 mm and less than 120 mm, preferably greater than 60 mm and less than 100 mm, in particular is about 80 mm. The lay length is the length of the route in the longitudinal direction of the cable that a wire pair needs for a 360 ° turn around the stranding center.

At the same time, preferably in (all) cross-sectional planes running through the cable, the distance between the wires of a wire pair is smaller than the distance between adjacent wire pairs. In particular, the two wires of at least two pairs of wires are in direct contact with one another, while they each maintain a distance from the next adjacent wire of the next pair of wires. For this purpose, spacer elements can be provided between the individual wire pairs, wherein the spacer elements can be stranded together with the wire pairs around the common stranding center. As a result, the individual pairs of wires run through the cable in a particularly orderly and compact manner.

According to the invention, the two wires of at least two wire pairs are each arranged adjacent to one another, while the two wires of at least one third wire pair are arranged at a distance from one another. The two wires of the third wire pair are arranged on opposite sides of the stranding center and are preferably each offset by approximately 90 ° with respect to the other two wire pairs. The third wire pair is preferably the high-speed wire pair (D + and D-) of the USB cable, and the others Both wire pairs are the super-speed wire pairs (SSTX + and SSTX-; SSRX + and SSRX-) of the USB cable. It is important here that the wires of the at least one third wire pair are also stranded around the common stranding center.

In a particularly preferred embodiment of the invention, the shields surrounding the wire pairs, such as the foil shields, each electrically contact the above-explained common shield of the cable which surrounds all wire pairs ("sum shield"). If the summation shield is grounded, the individual wire pair shields are also grounded or at a common electrical level. It has been found to be expedient if there are gaps in the foil screens that are due to the manufacturing process and each point radially outwards and thus face the sum screen. Furthermore, in this case it is possible to dispense with ground conductors such as drain wires, which in conventional cables are regularly provided in addition to the two wires of the wire pair within the foil shields.

Furthermore, it has been found to be expedient that in (all) cross-sectional planes running through the cable, the individual wires of the wire pairs each have essentially the same distance from the stranding center. In other words, the centers of the individual wires of the wire pairs each lie on a circle around the stranding center.

An envisaged distance between the individual pairs of wires can be ensured by filling elements which run like a rope in the longitudinal direction of the cable and which, together with the pairs of wires, can run helically around the common stranding center. As an alternative or in addition, the filling elements can be arranged in the cable in such a way that an essentially circular cable cross section results overall.

In a preferred embodiment, in addition to the wire pairs and the centrally arranged further wire, further conductors also run in the cable. These further conductors can be used to transmit data signals, control signals, electrical currents or the like as required. be provided. The other conductors do not necessarily run helically around the common stranding center, rather, they can also have a linear course, depending on requirements. Alternatively or additionally, the additional conductors can be provided instead of the above-mentioned rope-like filling elements and can assume their position in the cable.

Preferably, in each cross-sectional plane of the cable, each pair of cores can be assigned a straight line running through the stranding center and between the cores of the pair, which straight line does not intersect the cores of the pair.

In a preferred embodiment, a filling element runs like a rope in the longitudinal direction of the cable, which runs helically around the common stranding center together with the wire pairs, ensures a provided distance between the wire pairs, and which is molded onto the stranding center. This allows filling elements in the form of separate components, such as separate filling elements, to be dispensed with, and thus simplifies the manufacture of the cable and the logistics outlay for manufacture. The molded-on filling element can be formed from the material of the insulation that encases the core of the stranding center. The stranding center can thus be designed in one piece with the molded-on filling element and forms grooves or depressions into which the wires and / or wire pairs partially dip.

In a preferred embodiment, two electrical conductors of a pair of wires are sheathed with a common, electrically insulating sheath. This simplifies the production of such a wire pair.

In a preferred embodiment, an electrical conductor of a single core is covered with an electrically insulating sheath with an elliptical cross section. The single wire can be one of two wires in another wire pair. This also allows filling elements to be dispensed with and thus simplifies the manufacture of the cable.

Fig. 1

eine Schnittansicht eines herkömmlichen USB-3.0-Kabels,

Fig. 2

eine Schnittansicht einer ersten Ausführungsform eines erfindungsgemäßen Kabels,

Fig. 3a

eine Schnittansicht einer zweiten Ausführungsform eines erfindungsgemäßen Kabels,

Fig. 3b

eine Schnittansicht einer weiteren Ausführungsform eines Aderpaares eines erfindungsgemäßen Kabels, und

Fig. 4

eine Schnittansicht einer dritten Ausführungsform eines erfindungsgemäßen Kabels.

In the description that follows, the invention is described with reference to the accompanying drawings, which show details of the invention that are essential to the invention and are not explained in greater detail in the description. Show:

Fig. 1

a sectional view of a conventional USB 3.0 cable,

Fig. 2

a sectional view of a first embodiment of a cable according to the invention,

Fig. 3a

a sectional view of a second embodiment of a cable according to the invention,

Figure 3b

a sectional view of a further embodiment of a wire pair of a cable according to the invention, and

Fig. 4

a sectional view of a third embodiment of a cable according to the invention.

In Fig. 2 a first embodiment of a USB 3.x cable 10 "according to the invention is shown in cross section. This cable 10" has two pairs of wires 112, 114 (the two super-speed pairs of the USB cable), each of which has its own foil shield 15 are surrounded, which electrically contacts a summation screen 30. These two wire pairs 112, 114 are arranged on opposite sides of a central current-carrying wire 22 and run helically around a common stranding center 20 which is formed by the wire 22. The two wires of a third wire pair 116 (of the high-speed pair D +, D-) are provided at a distance from one another in the cable, namely on opposite sides of the central current-carrying wire 22 offset by 90 ° to the two wire pairs 112, 114. The wires of the third wire pair 116 also run stranded around the stranding center 20, so that the cable - apart from a twist around the stranding center 20 - has the same arrangement of strands in any cross-sectional planes. The two wires of the third wire pair 116 are arranged directly adjacent to the grounded summation shield 30, so that a quasi-mass-related transmission results practically without coupling in the direction of the central current-carrying wire 22.

Overall, the result is an essentially four-fold, rotationally symmetrical arrangement of the wires around the stranding center 20, on the one hand there being two wire pairs 112, 114 and, on the other hand, two individual wires of a third wire pair 116 in the cable 10 ″ are opposite one another.

Furthermore, the Fig. 2 that between the stranding center 20 and the two pairs of wires 112, 114 and the third pair of wires 116 in this embodiment, four filling elements 40 are arranged.

It should also be noted that the summation screen 30 has a mesh of electrically conductive threads or wires or an electrically conductive film.

In Fig. 3a a second embodiment of a USB 3.x cable 10 '"according to the invention is shown in cross section, which differs from the first embodiment in that the stranding center 20 has a molded-on filling element 40a. In the present embodiment, the molded-on filling element 40a is from the Material of the insulation is formed which encases the core 22. Thus, in the second embodiment, the stranding center 20 is formed in one piece with the molded-on filling element 40a. Furthermore, the stranding center 20 with the molded-on filling element 40a forms grooves or depressions into which the two pairs of wires 112, 114 and at least partially immerse the third wire pair 116.

For the rest, reference is made to the above-described features of the first embodiment of the invention, which can also be provided in the second embodiment.

In Figure 3b a further embodiment of the two wire pairs 112, 114 is shown, which differs from the second embodiment in that the two electrical conductors of the two wire pairs 112, 114 are surrounded by a common, electrically insulating sheath 200.

In Fig. 4 a third embodiment of a USB 3.x cable 10 "" according to the invention is shown in cross section, which differs from the second embodiment in that sheaths 202a, 202b, which each surround the two electrical conductors of the third wire pair 116, have an elliptical cross section exhibit.

In this embodiment, the stranding center 20 can have a circular cross-section as in the case of FIG Fig. 2 Have shown first embodiment. Alternatively, however, the stranding center 20 can also have molded-on filler elements 40a in a manner analogous to the second embodiment. Furthermore, this third embodiment can be implemented in FIGS Fig. 2 and 3a The embodiment shown of the two wire pairs 112, 114 or the in Figure 3b The embodiment shown of the two wire pairs 112, 114 have.
The invention is not restricted to the embodiments described. In particular, the cable according to the invention is not necessarily a USB cable. Furthermore, the cable according to the invention can also have more than three stranded wire pairs. To ensure a rotationally symmetrical structure, more than one pair of wires can be replaced by a pair of filling elements. According to the invention, the stranding of the wire pairs around a common stranding center is particularly important, the stranding center preferably being formed by the centrally arranged, current-carrying wire of a USB cable.

Claims (15)

1. Cable (10"; 10"'; 10"") having at least two wire pairs (112, 114), which are each configured for the transmission of a differential data signal, wherein the at least two wire pairs (112, 114) run helically around a common stranding center (20) in the longitudinal direction of the cable, and having at least one further wire pair (116), wherein the wires of the further wire pair (116) are arranged at a distance from one another on opposite sides of the stranding center (20), characterized in that the further wire pair (116) does not have its own shielding, wherein the wires of the further wire pair (116) adjoin a common grounded shielding (30) which surrounds all wire pairs (112, 114, 116).
2. Cable (10"; 10"'; 10"") according to claim 1, characterized by three wire pairs (112, 114, 116) running helically around the common stranding center (20).
3. Cable (10"; 10'"; 10"") according to claim 1 or 2, characterized in that the cable (10"; 10"'; 10"") is a USB cable.
4. Cable (10"; 10'"; 10"") according to claim 3, characterized in that the common stranding center (20) comprises a further wire (22) that preferably runs in the middle of the cable, in particular the current-carrying wire of the USB cable.
5. Cable according to claim 4, characterized in that the further wire (22) comprises a conductor with a larger cross-sectional area than the conductors of the wire pairs (112, 114, 116).
6. Cable according to claim 4 or 5, characterized in that the cross-sectional area of the conductor of the further wire (22) is greater than 0.5 mm² and less than 1 mm².
7. Cable (10"; 10"'; 10"") according to one of claims 3 to 6, characterized in that the common grounded shielding (30) forms the ground conductor of the USB cable.
8. Cable according to one of the preceding claims, characterized in that the lay length of the helical course of the wire pairs (112, 114, 116) is greater than 40 mm and less than 120 mm.
9. Cable (10"; 10'"; 10"") according to at least one of the preceding claims, characterized in that the distance between the wires of a wire pair (112, 114) in cross-sectional planes running through the cable is smaller than the distance between adjacent wire pairs (112, 114).
10. Cable (10") according to claim 1, characterized in that two wire pairs (112, 114) on the one hand and the two wires of the further wire pair (116) on the other hand are arranged on opposite sides of the stranding center (20).
11. Cable (10"; 10"'; 10"") according to at least one of the preceding claims, characterized in that the individual wires of the wire pairs (112, 114, 116) in cross-sectional planes running through the cable each have substantially the same distance from the stranding center (20).
12. Cable (10") according to at least one of the preceding claims, characterized by filling elements (40) running like a rope in the longitudinal direction of the cable, which helically run, together with the wire pairs (112, 114, 116), around the common stranding center (20) and ensure an intended distance between the wire pairs (112, 114, 116).
13. Cable (10"') according to at least one of the preceding claims, characterized by a filling element (40a) which runs like a rope in the longitudinal direction of the cable and which, together with the wire pairs (112, 114, 116), runs helically around the common stranding center (20), which ensures an intended distance between the wire pairs (112, 114, 116), and which is molded onto the stranding center (20).
14. Cable according to at least one of the preceding claims, characterized by two electrical conductors of a wire pair (112, 114), which are sheathed with a common, electrically insulating sheath.
15. Cable according to at least one of the preceding claims, characterized by an electrical conductor of a single wire (116), which is sheathed with an electrically insulating sheath having an elliptical cross section.

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