阅读说明：本技术 传感器线缆以及测量装置 (Sensor cable and measuring device ) 是由 戈斯·塞巴斯蒂安 英特曼·谢尔盖 温泽尔·约尔格 于 2019-03-13 设计创作，主要内容包括：本发明提出一种传感器线缆,其构造用于检测环境变量,并且沿纵向从第一端部延伸至第二端部并且具有线芯以及若干沿纵向相互间隔的、具有各自电阻值的电阻元件,其中所述电阻值与所述环境变量的值相关地发生变化。此外,提出一种具有这样的传感器线缆的测量装置。(The invention relates to a sensor cable which is designed to detect an environmental variable and which extends in a longitudinal direction from a first end to a second end and has a core and a plurality of resistance elements which are spaced apart from one another in the longitudinal direction and have respective resistance values, wherein the resistance values change in dependence on the value of the environmental variable. Furthermore, a measuring device with such a sensor cable is proposed.)

1. A sensor cable extending longitudinally from a first end to a second end and configured for sensing an environmental variable, and having:

-a wire core,

-a plurality of longitudinally spaced resistive elements having respective resistance values which vary in relation to the value of the environmental variable, wherein

Each resistive element defining a measurement section,

along the wire core, each resistance element leads a conductor, and the conductor has several turns in the respective measuring section in order to form the respective resistance element.

2. The sensor cable according to claim 1,

wherein the wire turns are meander-shaped.

3. The sensor cable according to claim 1,

wherein the number of turns is configured as a wire wound turn wound around the wire core.

4. The sensor cable according to any one of claims 1 to 3,

wherein the individual conductors and the turns are constructed from wire applied to a carrier.

5. The sensor cable according to claim 4,

wherein the carrier is applied on the wire core.

6. The sensor cable according to claim 4 or 5,

the carrier is designed as a common carrier, on which a plurality of conductors with the resistor elements are applied.

7. The sensor cable according to any one of claims 1 to 3,

wherein the conductor is configured as an enameled wire.

8. The sensor cable according to any one of claims 1 to 7,

wherein the resistive element is electrically connected at the first end in an end assembled state of the sensor cable.

9. The sensor cable according to any one of claims 1 to 8,

wherein a loop conductor is further arranged along the wire core, which loop conductor is electrically connected with the mutually connected resistive elements at the first end in an end-assembled state of the sensor cable.

10. The sensor cable according to any one of claims 1 to 9,

wherein the wire core and the resistive element are collectively surrounded by a protective jacket.

11. The sensor cable of any one of claims 1 to 10, integrated into an electrical cable to be monitored.

12. The sensor cable according to claim 11,

the cable to be monitored is designed as a charging cable, in particular as a charging cable for a motor vehicle.

13. A measuring device for detecting environmental variables has

A sensor cable extending in a longitudinal direction from a first end to a second end and for detecting an environmental variable, and having:

-a core

-a plurality of longitudinally spaced resistive elements having respective resistance values which vary in relation to the value of the environmental variable, wherein

-each resistance element defining a measurement section,

along the wire core, each resistance element leads a conductor, and the conductor has several turns in the respective measuring section in order to form the respective resistance element, and

an evaluation unit, to which the individual resistance elements are connected and which is designed to detect and evaluate the resistance values of the resistance elements.

14. The measuring device according to claim 13, which is designed to assign the individual measuring sections to a region of the sensor cable.

Technical Field

The present invention relates to a sensor cable for detecting an environmental variable. The invention also relates to a measuring device with such a sensor cable.

Background

The detection of environmental variables, in particular the detection of temperature, is well known in the art, for example for monitoring machines or also for monitoring cables. For this purpose, special sensor cables are used locally.

In particular in the case of charging lines for motor vehicles driven by electric motors, it is desirable to monitor the temperature with respect to a plurality of aspects, for example during charging. Such an aspect is, for example, the maximum charging current at which the charging cable is warmed up, in order to ensure "contact safety" of the cable or to avoid overheating and thus damage to the cable. In this case, it is particularly expedient to provide temperature detection along the entire length of the charging cable.

Furthermore, it is expedient to detect the local temperature, in particular in the region of the charging cable for a motor vehicle, for example at a defined point, a so-called "hot spot", for example in order to be able to ascertain the location of the occurring damage point.

Disclosure of Invention

Starting from this, the object of the invention is to provide a sensor cable and a measuring device, by means of which an environmental variable along the cable can be detected in a simple manner.

The object of the sensor cable is achieved according to the invention by a sensor cable and a wire core designed for detecting an environmental variable, and a plurality of resistance elements spaced apart from one another in the longitudinal direction and having respective resistance values. The resistance value varies in relation to the value of the environmental variable.

The wire core is used, for example, for mechanical stabilization of the sensor cable, for example, as a tension relief. For this purpose, the wire core preferably has a plastic part, for example, aramid-based or Polyethylene (PE) -based. In particular, the wire core is a (solid) plastic rope.

Alternatively, the wire core is designed as one or more electrical or optical transmission elements, which are surrounded by a common sheath, for example. The wire core is in this case configured, for example, as a sheath cable.

The sensor cable extends from a first end to a second end. In this case, each resistance element defines a measuring section along the sensor cable. For example, the resistance elements are arranged at regular intervals from each other along the sensor cable. In other words: the measuring section defines a section selected along the sensor cable, in which section an environmental variable, in particular a change in the environmental variable, can be detected in relation to the section, so that in the measuring section the (change in the) environmental variable, in particular the temperature, is detected during operation in relation to the measuring section, so that the location/position along the sensor cable at which the change in the environmental variable occurs is known.

For this purpose, each resistance element leads a conductor along the sensor cable, in particular along the wire core. In order to form the individual resistance elements, the individual conductors in the individual measuring sections have several turns.

Due to the turns in the measuring section, the specific conductor length (length of conductor per unit length) in the measuring section is particularly significantly increased compared to sections of the conductor outside the measuring section. Preferably, the specific conductor length in the measuring section is at least 10 times, preferably 100 times or 1000 times greater than the length section outside the measuring section.

Several turns are to be understood to mean, in particular, at least two turns, so that, by the winding configuration of the conductor, at least two conductor sections run next to one another, i.e., next to one another. However, it is preferred that significantly more conductor sections are arranged next to one another, for example at least 10, at least 20, at least 50 or also at least 100 conductor sections are arranged next to one another. In the region of the measuring section in the longitudinal direction, the free distance between the two conductor sections is preferably in the range of less than 5mm and in particular in the range of less than 2mm or may also in particular be in the range of less than 1 mm. The more compactly the conductor sections are arranged, the longer the particular conductor length.

By means of the higher specific conductor length, the conductor has a higher specific resistance in the measuring section than in the remaining region. If the particular conductor length is significantly longer in the region of the measurement section, the contribution of the remaining region to the overall resistance value of the conductor can be ignored. The change in the resistance value due to a local temperature increase in a zone outside the measurement zone can be at least neglected. In contrast, in the region of the measuring section, changes in the value of the environmental variable to be measured have a significant influence on the overall resistance value of the conductor. Overall, this results in that only the resistance value of the resistance element is taken into account for the detection of the environmental variable.

Thus, by means of the plurality of measuring sections distributed over the sensor cable in the longitudinal direction, local changes in the environmental variables can be detected and the position determined in a simple manner. In this case, for the determination of the position, the position of the individual measuring sections along the sensor cable is known.

According to a first preferred solution, the turns extend in a zigzag shape. The conductor therefore runs within the measuring section on the surface of the core correspondingly between the direction change points according to the type of the wavy line. The respective measuring section, at least one respective conductor section between the two direction change points, is therefore guided, in particular, only in a partial region of the circumferential surface of the conductor core, and does not run around the entire circumferential surface.

Wherein the individual conductors and the conductor turns are formed by a conductor applied to the carrier, in particular stamped on the carrier. According to a first solution, the carrier relates to the sheath of the wire core itself. That is, the wire is applied directly to the sheath. For this, known methods of applying the electrically conductive material are used, for example thermal spraying.

Preferably, however, a separate carrier is applied to the wire core. The separate carrier is preferably a film carrier, for example a film, or also a strip of a suitable (insulating) material. The carrier is fastened to the wire core, for example by gluing, and is applied, for example, parallel to the longitudinal direction. Alternatively, the carrier is wound around the wire core, depending on the manner of coating. The conductor lines are in particular imprinted by printing methods, as are known, for example, from the production of printed circuit boards (films).

In this case, a plurality of conductors with respective measuring sections, i.e. resistance elements, are expediently applied to a common carrier. Preferably, all resistance elements of the sensor cable are arranged on a common carrier.

According to a second preferred embodiment, the turns are formed by wire turns. At least in the measuring section, the conductor is therefore wound around the core and has a predetermined measuring pitch (turn pitch) there. In the region outside the measuring section, the conductor either extends parallel to the longitudinal direction or is also wound around the core, but with a larger lay length, which is referred to below as the predetermined lay length.

In the measuring section, the conductor usually has a further resistance, in particular a higher specific resistance, than outside the measuring section. The predetermined lay length is used in particular only for guiding the individual conductors along the sensor cable. Thus, the value of the measured lay length is preferably more than 10 times smaller than the value of the predetermined lay length, in particular more than 100 times smaller or more than 1000 times smaller. That is, the measured lay length is preferably at least 10 times smaller than the predetermined lay length, in particular more than 100 times smaller or even more than 1000 times smaller. The lay length is to be understood in particular as the distance between adjacent wire turns, viewed in the longitudinal direction. In other words: the individual conductors are wound "more compactly" around the core in the measuring section than around the rest of the core.

In the simplest case, the conductor is a (single strand) bare metal wire or a bare stranded wire. Preferably, the conductor relates to an insulated wire or a stranded wire.

Preferably, the environmental variable is temperature. In this case, it is advantageous, in particular in the case of temperature-dependent resistor elements, that the configuration of the sensor cable by means of the resistor elements has proven to be suitable for detecting the temperature or the temperature change. Thus, a sensor cable based on a simple measurement principle is thereby realized.

The detection of the environmental variable is preferably based on detecting a resistance value which changes in relation to said environmental variable and then deducing the value of said environmental variable. This solution is based on the idea that a corresponding resistance value occurs at a certain value of the environment variable. This feature is exploited to derive the value of the environmental variable from the detected resistance value. For example, the resistance value is gradually associated with a change in the environmental variable. That is, as the value of the environmental variable increases, the resistance value increases. By the configuration of the measuring sections realized by the wire turns, it is possible to detect the environmental variable, in particular the change of the environmental variable, in each measuring section individually.

Furthermore, due to the construction of the resistive element realized by means of the conductor, the sensor cable is insensitive with respect to mechanical strains, such as bending or torsion. Thus, a reliable detection of the environmental variable itself is ensured at or after the time of mechanical strain of the sensor cable.

Preferably, the resistance elements have respective different resistance values. In particular, the respective resistance values in the case of the end-assembled sensor cable decrease continuously in the longitudinal direction, i.e. correspondingly with a uniform resistance value. An end-mounted sensor cable is to be understood to mean, in particular, a sensor cable that is cut to length, is connected to an evaluation unit for evaluating the detected environmental variables, and is integrated into a component to be monitored, for example, an electrical cable.

The different resistance values are preferably achieved in that the resistive elements each have a different number of turns. That is, the number of turns of the resistive element is proportionally related to the resistance value belonging thereto. In the preceding example, it was explained that, in the case of a reduced resistance value, the corresponding resistive element also has a reduced number of turns.

Alternatively, the resistance value of each resistance element continuously increases from the first end portion toward the second end portion.

The advantage of this solution is that the individual resistance elements have a unique resistance value at constant temperature. Therefore, each resistance element can be identified even when the temperature is constant. This further simplifies the distribution of the individual measurement sections along the sensor cable.

In order to achieve a uniform length of the resistive elements and thus of the measuring sections, in a suitable further development the resistive elements each have a different spacing, which is the distance between the respective longitudinally adjacent turn or conductor sections. In the case of wire-wound turns, the resistive elements therefore have different measuring pitches. For example, the distance between adjacent turn sections of the resistive element increases as the resistance value becomes smaller. That is to say that the number of turns which is reduced for each resistance element (for forming different resistance values) is coordinated with the increase in the corresponding distance, i.e. for example with the increase in the corresponding measuring lay length, so that the resistance elements have the same geometric length relative to one another. This further achieves a simple and regular division of the sensor cable in which the individual measuring sections are implemented.

According to a suitable embodiment, the respective measuring section has a length which has a value of more than 1cm, in particular more than 5cm, and is for example in the range of 5cm and 10 cm. In each measuring section, the resistance element is thus designed with a resistance value which is advantageous with regard to the sensitivity and/or accuracy with which the environmental variable is detected. This solution is based on the idea that a longer length of the conductor, and therefore also "more" material, in particular temperature-dependent material, in the measuring section is influenced by the environmental variables, in particular by the temperature, and thus an accurate detection thereof is achieved. At the same time, the limitation of the length allows the detection of a position resolution of the environment variable. In principle, depending on the application, significantly longer measuring sections, for example measuring sections longer than 10cm, for example in the range from 20cm to 100cm, can also be achieved.

According to a preferred embodiment, in particular with wound wire turns, the conductor is designed as an enameled wire. Enamelled wires, which are constructed as electrical resistance elements, have proven to be advantageous in particular with regard to their material and dimensional properties.

It is also preferable that the enamel wire has a diameter of which a value is in a range of 0.04mm to 0.06 mm. Thereby achieving a sensor cable with a smaller diameter. The availability of the sensor cable is thereby increased. Such an enameled wire can also be wound very compactly around the core.

Preferably, the resistive element has a temperature coefficient of more than 3.5K, independently of the respective configuration of the wire turns or independently of the meander-shaped turns^-1In particular greater than 5K^-1The material of (1). Such material is for example copper or steel. The above-mentioned values of the temperature coefficient relate to numerical data under preferably standardized conditions, i.e. for example at 20 ℃. Furthermore, the temperature coefficient is preferably linear over a desired temperature range, for example between 40 ℃ and 100 ℃, which is advantageous for changes in the resistance value when the temperature changes. The temperature coefficient is to be understood broadly, in particular, as a coefficient which describes the relative change in a physical quantity, in particular the resistance, when the temperature changes relative to a predetermined reference temperature.

According to a suitable solution, in the assembled state of the ends of the sensor cable, the resistive element and the first end are electrically connected to each other. In other words: each conductor configured as a single resistive element is shorted at a first end of the end-assembled sensor cable. It can be seen that the advantage of the described solution consists in a simple analysis of the detection of the environmental variables. For this purpose, the sensor cable can be connected, for example, at both ends to an evaluation unit, by means of which the resistance value of the circuit formed by the short circuit at the first end is detected, in particular measured, during operation.

In a suitable further development, a return conductor is also arranged along the core. The loop conductors are, for example, applied together on a common carrier or wound around a wire core. Preferably, the loop conductor is electrically connected at a first end to the mutually connected resistance elements.

In this case, the advantage of the further development is that the individual resistance elements can be measured independently and individually in order to determine the resistance values and thus also the values of the ambient variables. In order to form the loop, the evaluation unit is connected to the loop conductor at the second end only, for example, by one connection and is connected alternately to the respective conductor to be measured by another connection. In the case of a predetermined current and an impressed current in the circuit, the resistance value of the resistance element can be deduced by the voltage drop occurring across the resistance element formed by the conductor.

According to a suitable solution, the wire core and the resistance element are jointly surrounded by a preferably transparent protective sheath. In particular, the resistor element formed from the conductor is thus protected from mechanical influences, such as, for example, friction or impacts. Due to the transparency of the protective sleeve, the position of the individual measurement sections can be determined.

In a preferred solution, the sensor cable is integrated into the cable to be monitored. The sensor cable is integrated into the cable structure, for example, together with other cable elements, for example, power supply lines, and is surrounded by a common protective jacket, for example, together with the other cable elements. Alternatively or additionally, the core of the sensor cable is designed as an electrical cable. In this case, the measuring section of the sensor cable, which is formed by the conductor, then surrounds the cable to be monitored. Furthermore, the sensor cable preferably extends along the total length of the cable to be monitored.

According to a preferred further development, the cable to be monitored is designed as a charging cable, in particular as a charging cable for a motor vehicle driven by an electric motor. A charging cable is to be understood here to mean, in particular, a cable for charging a battery of a motor vehicle driven by an electric motor, which battery supplies the electric traction motor. For this purpose, the charging cable is preferably designed to conduct a current with a value of more than 10A, and often even more than 100A, and for connection to a motor vehicle, the charging cable usually has a standardized charging plug, for example a type 1 plug or a type 2 plug.

By integrating the sensor cable in such a charging cable, a detection of "hot spots" along the charging cable is achieved in particular by the arrangement of the measuring sections along the sensor cable as described above.

The object is achieved according to the invention for a measuring device for detecting an environmental variable, which measuring device has the aforementioned sensor cable and an evaluation unit, to which the individual resistance elements of the sensor cable are connected. The evaluation unit is also designed to detect and evaluate the resistance value of the resistance element.

According to a preferred embodiment of the evaluation unit, the resistive elements are electrically connected to one another at a first end of the sensor cable, as is mentioned, for example, in the description of the sensor cable.

Preferably, the measuring device is designed to assign the individual measuring sections to a region of the sensor cable. In other words: the measuring device is designed to assign the position of the individual measuring sections along the sensor cable, so that, in particular, a position-resolved detection of the environment variable is possible.

The evaluation unit has suitable components in particular for detecting and evaluating the resistance value of the resistance element and thus the value of the environmental variable. For example, a voltage divider circuit is realized by means of the component, by means of which a single resistance value can be detected in a simple manner. Alternatively, the resistance value is determined by means of a wheatstone bridge measurement. In principle, the detection and the method of the resistance value are known and are therefore not deep within the scope of the present application. In principle, all known methods for detecting the resistance value can be implemented with the aid of an evaluation unit.

According to the solution, for manufacturing the sensor cable, different methods are provided.

In the case of solutions with a carrier, as is customary with coatings, the carrier is applied around the wire core in accordance with a coating method. Alternatively, the carrier is connected to the wire core in a materially bonded manner, for example by gluing.

In the case of solutions with wire-wound turns or even with a coated carrier, for example, a plurality of winding devices equipped with conductors and arranged laterally in the line direction are connected one behind the other in the line direction, for example, depending on the type of tangential coating machine. The wire core is guided through a winding device. In this case, the winding device rotates around the wire core.

In the case of the wire-wound turns, the conductor is wound around the core with a predetermined lay length. In order to form the resistor element, for example, the rotational speed of the winding device is increased at predetermined points, and the lay length of the individual conductors is therefore shortened. In the case of the wound turns, a winding device is preferably provided for each measuring section. In other words: at the location of the sensor cable, where at least one measuring section is to be formed, the rotational speed of at least one winding device is increased, so that the thus shortened lay length forms at least one measuring section. Preferably, the method for manufacturing a sensor cable is implemented according to the type of continuous process. In this case, the sensor cable is first of all unassembled, that is to say not wound up in a predetermined length, for example on a cable reel.

Preferably, in the case of the method, a prescribed number of different resistance elements are repeatedly formed periodically. Here, the resistance value of the resistance element decreases or increases continuously in the longitudinal direction. To produce an end-assembled sensor cable, the unassembled sensor cable is cut to length in a predetermined length, wherein the end-assembled sensor cable has a number of resistive elements which is less than a defined number of resistive element-s. In other words: if the unassembled sensor cable has, for example, 11 different resistive elements which repeat periodically when there is no cut-to-length state, the sensor cable cut to length from the unassembled sensor cable has a maximum of 10 resistive elements. The sensor cable with 10 resistive elements is at the same time a "as long as possible" sensor cable, which can be made of an unassembled sensor cable with 11 resistive elements.

In order to achieve a defined assignment of the individual resistance elements along the sensor cable in the case of an end assembly of the sensor cable, a so-called zero point measurement is preferably carried out. In this case, the sensor cable has preferably more resistance elements and therefore more measuring sections in the unassembled state, as described above, than the number of measuring sections required in the end-assembled state. If, for example, for the purpose of application, 10 measuring sections are required for the sensor cable assembled along the end, then in the case of the production of the unassembled sensor cable, preferably at least 11 measuring sections are arranged on the wire core. This has the result that, after the sensor cable has been cut to length, one of the 11 measuring sections is no longer present, and therefore a resistance value is no longer present when the individual measuring sections of the cut to length sensor cable are measured from end to end. What is achieved with the precondition that the sensor cable is end-assembled for the correct end is that the resistance value following the missing resistance value can be regarded as the first resistance value and thus as the first measurement region of the sensor cable. In other words: such interruptions, i.e. the missing measurement sections, "mark" the separation sites.

In the case of end assembly of the sensor cable, the aforementioned zero point measurement is carried out, for example, before the first use. The individual conductors are short-circuited at a first end and connected at a second end, for example, to a test circuit which measures the individual resistance elements formed by the conductors from end to end and determines the position of the measurement region on the basis of the measurements. Alternatively or additionally, the zero point measurement can also be performed by the evaluation unit. It should be noted in particular here that the sensor cable is subjected to a constant temperature during the zero-point measurement in order not to adversely affect the zero-point measurement.

In view of the advantages mentioned for the sensor cable and the preferred solution should also be applicable to the measuring device and vice versa.

Drawings

Embodiments of the invention are further elucidated in the following on the basis of the drawing. The described embodiments of the invention are partly shown in a very simplified illustration.

FIG. 1 shows a cross-sectional view of a sensor cable;

FIG. 2 shows a side view of an end-assembled sensor cable having two measurement sections;

FIG. 3 shows a partial view of a carrier on which conductors and resistive elements are mounted;

FIG. 4 shows a schematic block diagram of a sensor cable to be assembled; and

fig. 5 shows a schematic representation of the charging of a motor vehicle connected to a charging post by means of a charging wire.

In the figures, components with the same function are indicated with the same reference numerals.

Detailed Description

The sensor cable 2, which is shown diagrammatically in a cross-sectional representation in fig. 1, extends in the longitudinal direction L from a first end 4 (see fig. 2) to a second end 6 (see fig. 2) and is configured for detecting an environmental variable, which in the exemplary embodiment is a temperature.

Furthermore, the sensor cable 2 has a core 8. In the present embodiment, the wire core 8 has an aramid-based plastic cord and is formed in particular from such a plastic cord. The core 8 is used for mechanical stabilization of the sensor cable 2.

The sensor cable 2 also has a plurality (more than 2), in the exemplary embodiment according to fig. 1 17, of resistance elements 10 (see fig. 2) which are spaced apart from one another in the longitudinal direction L. The resistance elements 10 each have a resistance value that changes in relation to the value of the environmental variable. Each resistive element 10 defines a measurement zone 12 (see fig. 2).

In order to form the resistor elements 10, each resistor element 10 leads a conductor 14 along the wire core 8, wherein the conductor 14 has a plurality of turns 16 in the region of the measuring section 12. The turns 16 are configured in the embodiment of fig. 1 and 2 as wire-wound turns, in which case the conductor 14 is wound around the wire core 8.

In an alternative embodiment, the turns 16 are designed as meander-shaped turns 16, which are designed in particular as wires mounted on a carrier 17, as is shown in fig. 3.

In the case of this alternative solution, the carrier 17 is preferably mounted around the wire core 8, in particular in a cladding-like manner.

In the exemplary embodiment according to fig. 1 and 2, the resistance element 10 is formed by a conductor 14, for example a lacquered wire, which is arranged circumferentially around the wire core 8 (see fig. 2). Here, only one end of each conductor 14 can be seen in fig. 1. The conductor 14 has a diameter D in this embodiment, which has a value in the range of 0.04mm to 0.06 mm.

Thereby a very thin sensor cable 2 can be further achieved. Said very thin is to be understood in particular as meaning that the diameter of the sensor cable 2 has a value in the range from 1mm to 5 mm.

In the present embodiment, the wire core 8 and the resistive element 10 are jointly surrounded by a protective sheath 15 in order to achieve mechanical protection of the sensor cable 2. The protective sleeve 15 is preferably also constructed in the alternative by a carrier 17.

Independently of the embodiment variant, the conductor 14 has a temperature-dependent resistance, which is used for simple and cost-effective detection of the environmental variable, in particular the temperature. In the present exemplary embodiment, the conductor 14 is made of copper or steel, for example, and in particular is formed of copper or steel.

The end-assembled sensor cable 2 shown in fig. 2 serves to understand the construction of the resistive element 10 in detail by means of the respective conductor 14.

Each resistance element 10 leads a conductor 14 along the sensor cable 2, i.e. in the longitudinal direction L. In the present embodiment with a wound conductor 14, the conductor is in particular at a predetermined lay length λ_VWound around the core 8. In order to form the individual resistance elements 10, the conductor 14 measures the lay length λ in each measuring section 12 by means of a plurality of turns 16 formed as wire turns_MWound around the core 8. That is, to construct the resistance element 10, the individual conductors 14 are wound "more compactly" around the wire core 8 within the measuring section 12 than around other portions of the wire core 8. In fig. 2, this is shown by way of example in terms of two mutually spaced measuring sections 12.

In general, by means of the winding 16, whether wound or meandering, a specific conductor length and thus a specific resistance (resistance per unit length of the sensor cable 2) in the measuring section 12 is increased in particular markedly in comparison with sections of the conductor 14 outside the measuring section 12.

By means of this solution, it is possible to detect the environmental variable and in particular the change of the environmental variable within the measuring section 12. That is, if the environmental variable within the measurement section 12 changes, the resistance value of the resistive element 10 constructed from the conductor 14 also changes. The changed resistance value is detectable and in this way the (changed) environmental variable can be deduced back.

Each measuring section 12 has a length I, the value of which is greater than 1cm, in particular greater than 2cm, and in particular between 2cm and 5 cm. By combining the length I with the larger, specific conductor length formed by the turns 16 in the measuring section 12, an accurate and sensitive detection of the environmental variable is achieved in the measuring section 12, since "more" material is present in the measuring section 12, which is influenced by the environmental variable.

Furthermore, a return conductor 18, which is shown in fig. 2 only in the region of the second end 6, is arranged. The return conductor 18 likewise extends along the core 8. In the present embodiment with the turns 16 embodied as wire turns, the return conductor is wound around the core 8 similarly to the conductor 14, however, for example, only with a predetermined pitch λ_VAnd (4) winding. The return conductor 18 does not typically form the resistive element 10.

In the variant shown in fig. 3, a plurality of conductors 14 are applied, in particular stamped, on a carrier 17, in particular depending on the type of conductor. The carrier 17 is a film carrier 17. The individual conductors 17 extend outside the measuring section 12 in a straight line and in particular parallel to the longitudinal direction L1 of the carrier 17. In the region of the measuring section 12, the individual wires run in a number of individual turns 16 of a meander or wave shape. In this case, the turns 16 are to be understood as meaning regions of the conductor which run in alternating directions. In the present exemplary embodiment, each resistance element 10/measuring section 12 shows 12 wire turns. The measuring section 12 preferably has the aforementioned length I.

Preferably, all the resistive elements 10 of the sensor cable 12 are arranged on a common carrier 17. Furthermore, a return conductor 18, which extends in particular in a straight line, is preferably likewise applied to the carrier.

The carrier 17 is preferably wound around the wire core 8 according to a coating.

A schematic illustration of the sensor cable 2 to be assembled is shown in fig. 4. For assembling the sensor cable 2, the sensor cable originating from the unassembled "continuous manufacturing" is cut to length at the first end 4 and the second end 6. "continuously produced" is to be understood in particular to mean that the sensor cable 2 is produced according to the type of continuous process in such a way that it has a defined number (11 according to fig. 4) of resistor elements 10, which have a correspondingly defined resistance value, repeatedly in a periodic manner. In the present exemplary embodiment, the 11 resistor elements 10 are shown virtually by a number with a frame.

The resistive elements 10, which are constructed from conductors 14, are connected to the first end 4 of the sensor cable 2 in an electrically interconnected manner. At the second end 6 of the sensor cable 2, the single conductor 14 is guided into the plug 24. By means of this assembly, the connectability of the sensor cable 2 can be achieved, for example, by means of an evaluation unit 22, which determines the individual resistance elements 10 and allocates their position along the sensor cable, in particular before the sensor cable 2 is used for the first time, for example after the zero point measurement method described.

As is evident in the exemplary embodiment according to fig. 4, the resistance value of the resistance element 10 numbered 5 is missing in the sensor cable 2 after the cut-to-length operation. Therefore, when the resistance value gradually decreases between the successive resistance elements 10, the resistance element numbered 6 has the next lower resistance value. Thus, in accordance with the principle of zero point measurement, the evaluation unit 22 "knows" that the resistance element 10 with the reference number 6 is the first resistance element 10 of the sensor cable 2 (viewed from the plug side). Based on the above information, it is possible, for example, to assign the individual resistance elements 10 and thus the individual measuring sections 12 to positions along the sensor cable 2, starting from the evaluation unit 22. This enables, in particular, the position-resolved detection of the environment variable, i.e., the temperature detection. The advantage of this solution is that the detection of "hot spots" is achieved in a simple manner.

Fig. 5 shows a schematic illustration of the charging of a motor vehicle 40 connected to a charging post 38 by means of a cable 36 configured as a charging cable. The motor vehicle 40 relates to an electric motor driven motor vehicle 40.

The sensor cable 2 is integrated in the cable 36 in the exemplary embodiment according to fig. 5. That is to say, the sensor cable 2 is arranged in a charging cable, apart from several not shown supply lines (conducting the charging current LS), and is surrounded, for example, together with said supply lines, by a common outer jacket. Alternatively, the core 8 has a power supply line, so that the charging cable and the sensor cable are configured as a single cable 36.

The evaluation unit 22 is in the present exemplary embodiment integrated in the charging column 36 and is configured to communicate with a control unit 42 which controls the charging current LS.

The sensor cable 2 is used to monitor the temperature within the cable 36 during charging. If this temperature exceeds the temperature in the cable 36 caused by the charging current LS flowing through it, for example by a predetermined value, this is detected by the evaluation unit 22 and communicated to the control unit 42, for example in the form of a signal S. The control unit 42 then reduces the value of the charging current LS or completely stops the charging process. Thereby preventing thermal overheating and consequent damage to the cable 36.

The present invention is not limited to the foregoing embodiments. On the contrary, other variants of the invention may be derived therefrom by those skilled in the art without going against the subject of the invention. Furthermore, in particular, all individual features described in connection with the above embodiments can also be combined with one another in other ways, and do not depart from the subject matter of the invention.