Cable with abnormality detection function

Abstract

To provide a cable with an abnormality sigh detection function and an electric wire abnormality sign detection device which can detect a sign of disconnection of an electric wire without depending on a position in an axial direction of the electric wire, with similar sensitivity.SOLUTION: A cable 1 with an abnormality sign detection function has: one or a plurality of target electric wires 2A to 2D having electric wire conductors 21A to 21D, and an electric wire coating 22 coating outer peripheries of the electric wire conductors 21A to 21D; one or a plurality of detection wires 3A to 3C having detection wire conductors 31A to 31C and a detection wire coating 32 coating outer peripheries of the detection wire conductors 31A to 31C; and a sheath 5 coating outer periphery of an electric wire group G including the target electric wires 2A to 2D and the detection wires 3A to 3C, wherein the detection wire conductors 31A to 31C have bending resistance lower than those of the electric wire conductors 21A to 21D, and the sheath 5 is formed as an extrusion molding which is brought into direct contact with the outer periphery of the electric wire group G, or is brought into close contact with the outer periphery of the electric wire group G and is brought into close contact with the surface of an inner peripheral layer 4 coating the electric wire group G.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a cable with an abnormality sign detection function and an electric wire abnormality sign detection device. [Background technology]

[0002] Electric wires are installed and laid in various electrical and electronic devices, transportation equipment, buildings, public facilities, etc., and over time, they may suffer damage such as breakage. For example, repeated bending and vibration of an electric wire can cause metal fatigue, leading to breakage of the conductor that makes up the wire. It is preferable to detect damage such as breakage at a precursory stage, such as when metal fatigue is progressing, before it actually occurs. If damage to electric wires can be detected at a precursory stage, measures such as replacing the wire can be implemented, preventing malfunctions caused by the damage, such as the failure of equipment to which the wire is connected.

[0003] As a cable intended to detect signs of damage to electric wires, for example, Patent Document 1 discloses a cable with a wire breakage detection function that includes a detection wire having a conductor made of multiple strands twisted together and a detectable wire having a conductor made of multiple strands twisted together, where the twist pitch of the conductor of the detection wire is longer than the twist pitch of the conductor of the detectable wire.By making the twist pitch of the conductor of the detection wire longer than the twist pitch of the conductor of the detectable wire, the flex life of the detection wire is made shorter than the flex life of the detectable wire, thereby enabling prediction of wire breakage.

[0004] Furthermore, Patent Document 2 discloses a wire break detection device including an electric cable consisting of a plurality of electric wires, an electric shield layer covering the plurality of electric wires, and a sheath covering the electric shield layer, a wire break detection wire consisting of a conductor wire provided in the electric shield layer and an insulating layer surrounding the conductor wire, a voltage source electrically connected to the conductor wires, a first detector electrically connected to the conductor wires, and a second detector electrically connected to the electric shield layer. The flex life of the wire break detection wire is set shorter than the flex life of the electric wires. The document describes that a voltage is applied to the conductor wires of the wire break detection wire by the voltage source, and a wire break in the electric shield layer is predicted based on the detection signals of the first detector and the second detector. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-182716 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-305478 Summary of the Invention [Problem to be solved by the invention]

[0006] As described in Patent Documents 1 and 2, it is possible to detect signs of wire breakage in a target wire by providing a detection wire that is more likely to break when bent than the target wire and monitoring the breakage of the detection wire. However, simply providing a detection wire does not necessarily ensure high sensitivity in detecting wire breakage in the target wire. In Patent Document 1, the detection wire and multiple detectable wires are collectively covered by a sheath, while in Patent Document 2, multiple wires are covered by an electric shield layer with a wire breakage detection wire. Here, in the configurations of Patent Documents 1 and 2, there is a gap between the multiple target wires and the covering material that covers their outer periphery, i.e., the sheath and the electric shield layer, allowing the multiple target wires to move within the space surrounded by the covering material. If such movement of the target wires occurs while the target wires are repeatedly subjected to bending and vibration, the positional relationship between the target wires and the detection wire may change unevenly depending on their position along the cable axis. In other words, the target wire and the detection wire may have different relative positions depending on their positions along the axial direction.

[0007] As a result, the relationship between the load received by the target electric wire and the load received by the detection wire due to bending or vibration varies depending on the position along the axial direction. As a result, even if the same load is applied to the target electric wire due to bending or vibration, depending on the position along the axial direction where the load is applied, there may be cases where the detection wire breaks and a sign of a disconnection in the target electric wire can be detected, or cases where the detection wire does not break and a sign of a disconnection in the target electric wire cannot be detected. As such, there is a possibility that the sensitivity in detecting a sign of a disconnection in the target electric wire may vary depending on the position.

[0008] When detecting signs of damage such as a break in an electric wire, it is preferable to be able to detect the signs of damage with the same sensitivity regardless of the position along the axial direction where the signs of damage occur. In equipment such as automobiles, it is difficult to predict the position of the electric wire where damage will occur, but regardless of the position where the damage occurs, it may lead to malfunctions such as a malfunction of the equipment. Therefore, it is important to detect signs of electric wire damage regardless of the position and take measures such as replacing the electric wire. In particular, in places where the impact of electric wire damage is significant, such as automobile brake systems, it is desirable to detect signs of electric wire damage with high sensitivity.

[0009] In view of the above, the object of the present invention is to provide a cable with an abnormality sign detection function and an electric wire abnormality sign detection device that can detect signs of an electric wire breakage with the same sensitivity regardless of the position along the axial direction of the electric wire. [Means for solving the problem]

[0010] The cable with an abnormality detection function according to the present disclosure comprises one or more target electric wires each having a wire conductor and a wire coating covering the outer periphery of the wire conductor, one or more detection wires each having a detection wire conductor and a detection wire coating covering the outer periphery of the detection wire conductor, and a sheath covering the outer periphery of a group of electric wires including the target electric wires and the detection wire, wherein the detection wire conductor has lower bending resistance than the electric wire conductor, and the sheath is formed as an extrusion molded body that is either in direct contact with the outer periphery of the group of electric wires or in contact with the outer periphery of the group of electric wires and the surface of an inner layer that covers the group of electric wires.

[0011] The electric wire abnormality detection device according to the present disclosure comprises a measurement unit and a notification unit, wherein the measurement unit measures the characteristic impedance of the detection line conductor for the cable with abnormality detection function, and the notification unit notifies the outside that there are signs of a break in the target electric wire when the characteristic impedance of the detection line conductor measured by the measurement unit changes by more than a reference value. [Effects of the Invention]

[0012] The cable with abnormality sign detection function and the electric wire abnormality sign detection device according to the present disclosure can detect signs of an electric wire break with the same sensitivity regardless of the position along the axial direction of the electric wire. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view showing the configuration of a cable with an abnormality sign detection function according to a first embodiment of the present disclosure, in which an enlarged detection line is shown within a rectangle. [Figure 2] FIG. 2 is a schematic diagram illustrating the configuration of an electric wire abnormality sign detection device according to one embodiment of the present disclosure in a state where a break occurs in a detection line conductor. [Figure 3] 3A and 3B are diagrams illustrating the configuration of a cable with an abnormality sign detection function according to a second embodiment of the present disclosure. Fig. 3A is a perspective view, and Fig. 3B is a cross-sectional view. Fig. 3A illustrates a state in which the sheath has been removed. [Figure 4] 4A and 4B are diagrams illustrating the configuration of a cable with anomaly sign detection function according to a third embodiment of the present disclosure. Fig. 4A is a perspective view, and Fig. 4B is a cross-sectional view. Fig. 4A shows a state in which the sheath has been removed. Fig. 4C is a cross-sectional view illustrating the laminated structure of a laminated tape that constitutes the cable with anomaly sign detection function. DETAILED DESCRIPTION OF THE INVENTION

[0014] [Description of the embodiments of the present disclosure] First, an embodiment of the present disclosure will be described. A cable with an abnormality detection function according to an embodiment of the present disclosure comprises one or more target electric wires each having a wire conductor and a wire coating covering the outer periphery of the wire conductor, one or more detection wires each having a detection wire conductor and a detection wire coating covering the outer periphery of the detection wire conductor, and a sheath covering the outer periphery of a group of electric wires including the target electric wires and the detection wire, wherein the detection wire conductor has lower bending resistance than the electric wire conductor, and the sheath is formed as an extrusion molded body that is either in direct contact with the outer periphery of the group of electric wires or in contact with the outer periphery of the group of electric wires and the surface of an inner layer that covers the group of electric wires.

[0015] The cable with anomaly detection capability includes a detection wire having a detection wire conductor with lower bending resistance than the electric wire conductor. Therefore, when a load is repeatedly applied to the cable with anomaly detection capability due to bending or vibration, the detection wire breaks more quickly than the target electric wire. When a break occurs in the detection wire, the break can be detected through electrical measurements, such as characteristic impedance measurement, thereby detecting the occurrence of a break in the target electric wire before the target electric wire breaks. The sheath covering the outer periphery of the group of electric wires including the target electric wire and the detection wire is provided as an extrusion molded body that is in direct contact with the outer periphery of the group of electric wires or in contact with the inner circumferential layer that covers the group of electric wires. This makes it difficult for the positional relationship between each target electric wire and the detection wire to shift in the inner region of the sheath. Therefore, the target electric wires and the detection wire can maintain the same relative positional relationship at each position in the axial direction of the cable, and the relationship between the load applied to the target electric wire due to bending or the like and the load applied to the detection wire can also be maintained the same at each position in the axial direction. As a result, it is possible to detect with high sensitivity signs of a break in the target electric wire by detecting a break in the detection wire, regardless of the position along the axial direction of the cable.

[0016] Here, the cable with anomaly detection function may include a plurality of the detection wires, and the detection wire conductors constituting the plurality of detection wires may have different bending resistances. Among the plurality of detection wires, those with low bending resistance may break even when a small load is applied, so that when a break occurs, it is possible to detect signs of a wire breakage in the target electric wire at an early stage. On the other hand, those with high bending resistance may not break until a large load is applied, so that when a break occurs, it is possible to detect an increased possibility of a wire breakage in the target electric wire. Therefore, by distinguishing and detecting which detection wire conductor has broken, it is possible to detect signs of a wire breakage in the target electric wire in stages according to the urgency of the wire breakage.

[0017] In this case, the plurality of detection wires may include a first detection wire having a first detection wire conductor and a second detection wire having a second detection wire conductor, the first detection wire conductor being composed of strands of a first metallic material, and the second detection wire conductor being composed of strands of a second metallic material having higher flex resistance than the first metallic material. This allows the second detection wire conductor to have higher flex resistance than the first detection wire conductor, and two detection wire conductors with different flex resistances can be provided by utilizing the difference in flex resistance between metallic materials. These detection wire conductors enable the detection of signs of a wire breakage in a target electric wire in stages. When an alloy such as a copper alloy is used as the metallic material, flex resistance can be widely controlled by the type and amount of added elements and manufacturing method, making it possible to provide a variety of detection wires depending on the urgency of the signs of a wire breakage to be detected.

[0018] The plurality of detection wires may further include a third detection wire having a third detection wire conductor, the third detection wire conductor including both wires of the first metallic material and wires of the second metallic material, and having higher bending resistance than the first detection wire conductor and lower bending resistance than the second detection wire conductor. This allows for three or more stages of detection of signs of disconnection in a target electric wire with a simple configuration using only wires made of two types of metallic materials.

[0019] The cable with anomaly sign detection function may include a plurality of the target electric wires, and the plurality of target electric wires may be arranged surrounding the detection wire, so that even if a sign of a disconnection occurs in any of the plurality of target electric wires, the sign can be detected with high sensitivity by the common detection wire.

[0020] The cable with anomaly detection capability may further include an outer detection layer between the sheath and the group of electric wires, which is a layered member including a conductive material. In this case, damage to the conductive material included in the outer detection layer may occur when the cable with anomaly detection capability is subjected to a sudden impact or external damage. Detecting damage to the conductive material through electrical measurements, such as measuring characteristic impedance, can detect signs of damage to the target electric wires, such as breakage or external damage, due to the application of an impact or the formation of external damage. The detection wire included in the group of electric wires is suitable for detecting signs of breakage of the target electric wires due to metal fatigue caused by bending or vibration, while the outer detection layer arranged outside the group of electric wires is suitable for detecting signs of breakage of the target electric wires due to the application of a sudden impact or external damage due to contact or friction with an external object. A cable including both the detection wire and the outer detection layer enables highly sensitive detection of signs of multiple types of damage caused by different causes in the target electric wires.

[0021] In this case, the conductive member constituting the outer detection layer may be a metal layer having a thickness smaller than the diameter of the detection line conductor, so that the outer detection layer is easily damaged, such as broken, by the application of an impact or contact with an external object, and therefore it becomes possible to sensitively detect signs of damage to the target electric wire.

[0022] The outer detection layer may be made of conductive tape and may be disposed so as to surround the group of electric wires. Furthermore, the conductive tape may be spirally wound around the group of electric wires with gaps between turns. Alternatively, the outer detection layer may be made of laminated tape, which may have conductive coating layers formed on both sides of a substrate formed as a tape-shaped insulator or semiconductor, and may be disposed so as to surround the group of electric wires. Regardless of the form of the outer detection layer, the simple configuration of the outer detection layer allows for sensitive detection of signs of damage to the target electric wires due to the application of impact or external injury.

[0023] An electric wire abnormality detection device according to an embodiment of the present disclosure includes a measurement unit and a notification unit, wherein the measurement unit measures the characteristic impedance of the detection line conductor for the cable with abnormality detection function, and the notification unit notifies an external device that there are signs of a break in the target electric wire when the characteristic impedance of the detection line conductor measured by the measurement unit changes by more than a reference value.

[0024] In the above-mentioned electric wire abnormality detection device, by detecting a break in the detection conductor due to a change in the characteristic impedance of the detection conductor, it is possible to detect the occurrence of a sign of a disconnection in the target electric wire and notify the outside. Because the cable with abnormality detection function to be detected as the detection target has a sheath formed as an extrusion molded body with good adhesion, the relative positions of the target electric wires and the detection wire are unlikely to shift in the inner area of ​​the sheath, so it is possible to detect signs of a disconnection in the target electric wire with high sensitivity and notify the user, etc., regardless of the position along the axial direction of the cable.

[0025] Here, the measurement unit preferably measures the characteristic impedance of the detection line conductor and the characteristic impedance of the conductive member constituting the outer detection layer for the cable with anomaly detection function, which has an outer detection layer including a conductive member between the sheath and the group of electric wires, and the notification unit preferably notifies an external device that there is a sign of damage to the target electric wire when the characteristic impedance of the conductive member measured by the measurement unit changes by a reference value or more. In this way, it is possible to detect with high sensitivity not only signs of disconnection of the target electric wire due to metal fatigue caused by bending or vibration, but also signs of disconnection of the target electric wire due to the application of a sudden impact and signs of external injury due to contact or friction with an external object, and notify the user, etc.

[0026] [Details of the embodiments of the present disclosure] Hereinafter, a cable with an abnormality sign detection function and an electric wire abnormality sign detection device according to an embodiment of the present disclosure will be described in detail with reference to the drawings. The cable with an abnormality sign detection function according to an embodiment of the present disclosure is a cable capable of detecting signs of damage to a target electric wire included in the cable. Furthermore, the electric wire abnormality sign detection device according to an embodiment of the present disclosure is a detection device capable of detecting signs of damage to a target electric wire, using the cable with an abnormality sign detection function according to an embodiment of the present disclosure as a target.

[0027] First Embodiment (1) Configuration of cable with anomaly detection function First, a cable with anomaly sign detection function according to a first embodiment of the present disclosure (hereinafter, sometimes simply referred to as a cable) will be described. Fig. 1 shows the configuration of a cable with anomaly sign detection function 1 according to the first embodiment of the present disclosure in a cross-sectional view cut perpendicular to the axial direction. The cable with anomaly sign detection function 1 includes target electric wires 2 (2A to 2D), detection wires 3 (3A to 3C), tape layers 4, and a sheath 5. In Fig. 1, the area of ​​the detection wire 3 is shown enlarged and enclosed in a rectangle.

[0028] The target electric wires 2 are electric wires that perform functions required in devices, such as power supply, voltage application, and communication, and are electric wires in the cable 1 that are targets for which signs of damage should be detected. The number of target electric wires 2 is not particularly specified and can be one or more, but preferably more than one. Each target electric wire 2 has a wire conductor 21 (21A to 21D) configured as a conductor wire and a wire coating 22 made of an insulating material that coats the outer periphery of the wire conductor 21. In the illustrated embodiment, the cable 1 includes four target electric wires 2A to 2D. Of these four, two are power feeders 2A and 2B. The other two are signal wires 2C and 2D with a conductor cross-sectional area smaller than that of the power feeders 2A and 2B, and are twisted together to form a twisted pair. In the figure, the outer edge of the twisted pair is indicated by a dashed line. For example, if the conductor cross-sectional area of ​​each power feeder 2A and 2B is 1.8 to 2.5 mm, 2 The conductor cross-sectional area of ​​each signal line 2C, 2D is 0.25 mm 2 An example of the embodiment is as follows.

[0029] As will be explained later, the detection wire 3 is an electric wire that detects the occurrence of a sign of a disconnection in the target electric wire 2 by breaking itself. The detection wire 3 includes a detection wire conductor 31 (31A-31C) configured as a conductor wire and a detection wire covering 32 made of an insulating material and covering the outer periphery of the detection wire conductor 31. The number of detection wires 3 is not particularly limited and can be one or more. Preferably, multiple detection wires 3 are included in the cable 1, and in the illustrated embodiment, three detection wires 3 are included. Each detection wire conductor 31 has lower bending resistance than the electric wire conductor 21 of the target electric wire 2. In this specification, the bending resistance of a conductor refers to the ease of breaking when bent and can be evaluated as the number of bendings until breaking when repeatedly bent at a predetermined angle. The greater the number of bendings, the higher the bending resistance. When the cable 1 includes multiple target electric wires 2, the bending resistance of the detection wire conductor 31 is lower than that of each of the electric wire conductors 21 of the multiple target electric wires 2. When the cable 1 includes the power feeder lines 2A, 2B and the signal lines 2C, 2D, the signal lines 2C, 2D, which have a smaller conductor cross-sectional area than the power feeder lines 2A, 2B, generally have lower bending resistance, and the detection line conductor 31 has even lower bending resistance than the signal lines 2C, 2D. Furthermore, when the cable 1 includes multiple detection lines 3, the bending resistance of the detection line conductors 31 of all of those detection lines 3 is lower than the bending resistance of the electric wire conductors 21 of each target electric wire 2.

[0030] When a plurality of detection lines 3 are provided, it is preferable that the detection lines 3 have different bending resistances of the detection line conductors 31. In the illustrated embodiment, a first detection line 3A, a second detection line 3B, and a third detection line 3C are provided, each including detection line conductors 31A to 31C with different bending resistances. The first detection line conductor 31A included in the first detection line 3A has the lowest bending resistance. The second detection line conductor 31B included in the second detection line 3B has the highest bending resistance. The third detection line conductor 31C included in the third detection line 3C has an intermediate bending resistance, higher than the first detection line conductor 31A and lower than the second detection line conductor 31B.

[0031] The following are examples of means for providing a difference in the bending resistance of the conductors 21, 31 between the target electric wire 2 and the detection wire 3, and between multiple detection wires 3. For example, when the stranded conductor is made of the same wires, the greater the number of wires, the higher the bending resistance. Also, when the number and material of the wires making up the conductor are the same, the thicker the wires making up the conductor, the higher the bending resistance. Furthermore, when the metal material making up the conductor exhibits high bending resistance as a material property, for example, when it has a large Young's modulus, a high modulus of rigidity, and a high bending strength, the bending resistance of the conductor increases. Furthermore, as described in Patent Document 1, the shorter the twist pitch of the wires in the conductor, the higher the bending resistance of the conductor.

[0032] In the illustrated embodiment, the wires constituting each detection wire 3 are thinner than the wires constituting each target electric wire 2. The detection wire conductors 31 of the three detection wires 3 include the same number of wires with the same diameter, but the detection wire conductors 31 include wires made of metallic materials with different bending resistance properties. Specifically, the first detection wire conductor 31A, which has the lowest bending resistance, is entirely made of wires 33 made of a first metallic material with relatively low bending strength. The second detection wire conductor 31B, which has the highest bending resistance, is entirely made of multiple wires 34 made of a second metallic material. The second metallic material has higher bending resistance than the first metallic material, i.e., it has higher bending strength than the first metallic material and exhibits higher bending resistance than the first metallic material when made into wires of the same diameter. The third detection line conductor 31C, which has intermediate bending resistance, includes both wires 33 made of a first metal material and wires 34 made of a second metal material. When an alloy is used as the metal material constituting the wires 33 and 34, a variety of bending resistances can be achieved depending on the type and amount of added elements and the manufacturing method. Suitable examples include a configuration in which copper (annealed copper) is used as the first metal material and a copper alloy is used as the second metal material, and a configuration in which a first copper alloy with a relatively low bending strength is used as the first metal material and a second copper alloy with a bending strength higher than that of the first copper alloy is used as the second metal material.

[0033] In the cable 1, all of the target electric wires 2 and detection wires 3 are bundled together to form a group of electric wires G. In the group of electric wires G, the relative arrangement of the target electric wires 2 and detection wires 3 is not particularly limited, but it is preferable to place the detection wire 3 in the center and arrange multiple target electric wires 2 around the outer periphery of the detection wire 3. In this case, if multiple detection wires 3 are provided, it is recommended to arrange these multiple detection wires 3 together in the center. The detection wires 3 and the target electric wires 2 may simply be bundled together as an electric wire bundle, but it is preferable to arrange the detection wire 3 in the center and wrap the target electric wires 2 spirally around the outer periphery of the detection wire 3.

[0034] A tape layer 4 is provided as an inner peripheral layer on the outer periphery of the electric wire group G. The tape layer 4 plays a role in bundling the target electric wires 2 and the detection wires 3 constituting the electric wire group G so that they do not separate from each other. The form and material of the tape layer 4 are not particularly limited, but a suitable example is a form in which a tape body made of an insulating material such as paper or resin is spirally wound around the outer periphery of the electric wire group G. The tape layer 4 is in close contact with the electric wire group G. In other words, it is in contact with the outer peripheral surfaces of the electric wires (here, the target electric wires 2A, 2B, and 2D) that face the outermost periphery of the electric wire group G among the electric wires 2A to 2D and 3A to 3C constituting the electric wire group G.

[0035] The sheath 5 is formed as an extrusion of an insulating material whose main component is a polymer material, and surrounds the outer periphery of the tape layer 4 to form the outermost periphery of the entire cable 1. The sheath 5 is in close contact with the outer periphery of the tape layer 4. In other words, the sheath 5 is in contact with the tape layer 4 over the entire outer periphery of the tape layer 4, with no gaps formed between the sheath 5 and the tape layer 4, except for unavoidable gaps. The sheath 5 may be formed of one layer or multiple layers, but in the illustrated embodiment it is formed of two layers, an outer layer 51 and an inner layer 52, with the outer layer 51 being made of a material that has better mechanical properties, such as abrasion resistance, than the inner layer 52.

[0036] (2) How to detect disconnection When the cable 1 described above is placed in equipment or the like and is subjected to repeated bending and vibration during use, metal fatigue may accumulate in the wire conductor 21 that constitutes the target electric wire 2, potentially leading to a break. If a break occurs in the target electric wire 2, the target electric wire 2 will no longer be able to perform its functions of power supply, communication, etc., and the equipment in which the cable 1 is placed will no longer be able to continue to function normally. Furthermore, a break in the target electric wire 2 may cause malfunctions or other problems in the equipment.

[0037] However, the cable 1 according to this embodiment includes, in addition to the target electric wire 2 that performs a predetermined function in equipment, etc., a detection wire 3 that includes a detection wire conductor 31 that has lower bending resistance than the wire conductor 21 of the target electric wire 2. If the cable 1 is repeatedly subjected to bending and vibration, the detection wire conductor 31, which has lower bending resistance, will break before the wire conductor 21. The break in the detection wire conductor 31 means that the target electric wire 2 is also being subjected to load due to bending and vibration, causing metal fatigue to accumulate in the wire conductor 21, and if the load continues to be applied, there is a possibility that the wire conductor 21 of the target electric wire 2 will also break. The break in the detection wire conductor 31 can be detected by electrical measurements, such as measuring the characteristic impedance.

[0038] In this way, by detecting a break in the detection wire conductor 31, which has low bending resistance, it is possible to detect signs of a break in the wire conductor 21 of the target electric wire 2 before a break actually occurs in the target electric wire 2. If measures such as replacing the target electric wire 2 with a new one are taken at the stage when a sign of a break in the target electric wire 2 is detected, it is possible to prevent problems caused by a break in the target electric wire 2. Note that in this specification, a break in the wire conductor 21 of the target electric wire 2 and a break in the detection wire conductor 31 of the detection wire 3 may be simply referred to as a break in the target electric wire 2 and a break in the detection wire 3.

[0039] In the cable 1 according to this embodiment, a tape layer 4 is provided in close contact with the outer periphery of the group of electric wires G, which includes the target electric wires 2 and the detection wires 3, and a sheath 5 is further provided around the outer periphery of the tape layer 4. The sheath 5 is formed as an extrusion molded body and is in close contact with the tape layer 4. Because the sheath 5 is formed as an extrusion molded body, the structure of the group of electric wires G, in which the target electric wires 2 and the detection wires 3 are grouped in a predetermined relative arrangement, is firmly held by the sheath 5, making it difficult for the positional relationship between the target electric wires 2 and the detection wires 3 to shift relative to each other. This makes it easy to maintain the same positional relationship between the target electric wires 2 and the detection wires 3 regardless of their positions along the axial direction of the cable 1. Furthermore, even when the cable 1 is subjected to external forces such as bending or vibration, the same positional relationship can easily be maintained at each position along the axial direction of the cable 1 without shifting.

[0040] If the positional relationship between the target electric wire 2 and the detection wire 3 changes depending on the position along the axial direction and over time, even if the same magnitude of external force is applied to the target electric wire 2 due to bending, vibration, etc., the relationship between the load received by the target electric wire 2 and the load received by the detection wire 3 may change depending on the position along the axial direction and over time. As a result, when the detection wire conductor 31 of the detection wire 3 breaks, the degree of metal fatigue accumulated in the wire conductor 21 of the target electric wire 2 will differ depending on the position in the axial direction and due to changes over time, and the imminence of the target electric wire 2 until it breaks, as indicated by the breakage of the detection wire conductor 31 (how much additional load is required to actually cause it to break), will vary depending on the position and time. However, in the cable 1 according to this embodiment, as described above, the positional relationship between the target electric wire 2 and the detection wire 3 is kept constant regardless of the axial position of the cable 1 or the passage of time. This makes it easier to maintain a constant relationship between the load on the target electric wire 2 and the load on the detection wire 3 when an external force such as bending or vibration is applied. Therefore, when a break occurs in the detection wire conductor 31 of the detection wire 3, detecting the break can serve as an indicator that the same level of metal fatigue has accumulated in the wire conductor 21 of the target electric wire 2, regardless of the position along the axial direction of the cable 1 or the time, and that the target electric wire 2 is experiencing signs of a break of the same degree of urgency. In other words, signs of a break in the target electric wire 2 can be accurately detected with sensitivity that is independent of the position or time.

[0041] In the embodiment described above, the group of electric wires G is bundled together with the tape layer 4, and the sheath 5 is provided around the tape layer 4. The tape layer 4 serves to enhance the stability with which the sheath 5 maintains the positional relationship between the target electric wires 2 and the detection wire 3. However, the tape layer 4 may be omitted from the cable 1. When the tape layer 4 is omitted, the sheath 5 may be formed as an extrusion molded body that directly adheres to the outer periphery of the group of electric wires G. In other words, the sheath 5 should be in contact with the surfaces of the electric wires that make up the group of electric wires G over the entire outer periphery of the group of electric wires G, with no gaps formed between the sheath 5 and the surfaces of the electric wires that make up the group of electric wires G, except for unavoidable gaps. Furthermore, a layer other than the tape layer 4 may be provided between the sheath 5 and the group of electric wires G, such as the outer detection layers 7 and 8 in the second and third embodiments described later. In this case, the assembly of all layers provided on the outer periphery of the group of electric wires G, including layers other than the tape layer 4, is made into an inner periphery layer, and the inner periphery layer is provided in close contact with the outer periphery of the group of electric wires G, and the sheath 5 is provided as an extrusion molded body in close contact with the surface of the inner periphery layer.

[0042] In the electric wire group G, the specific relative arrangement of the target electric wires 2 and the detection wires 3 is not particularly limited, but when multiple target electric wires 2 are provided, it is preferable to arrange the multiple target electric wires 2 so that they surround the detection wire 3, as described above. By arranging the detection wire 3 in this way at or near the center of the cable 1 surrounded by the multiple target electric wires 2, a large force is likely to be applied to the detection wire 3 when the cable 1 is bent. As a result, it becomes possible to sensitively detect signs of a break in the target electric wires 2 by breakage of the detection wire 3. When multiple detection wires 3 are provided, it is preferable to arrange the multiple detection wires 3 together in a position surrounded by the target electric wires 2, rather than arranging them separately from each other.

[0043] While at least one detection wire 3 is sufficient to detect a break in the target electric wire 2, as in the present embodiment, by providing multiple detection wires 3 and setting the detection wire conductors 31 of these detection wires 3 to have different bending resistances, signs of a break in the target electric wire 2 can be detected in stages. A detection wire conductor 31 with lower bending resistance breaks at an earlier stage when only a smaller load is applied, i.e., when metal fatigue has not accumulated significantly in the wire conductors 21 of the target electric wire 2, the breakage of the detection wire conductor 31 can detect signs of a break in the target electric wire 2 at a time when there is still some margin for imminent breakage. For example, in the above-described embodiment, when only the first detection wire conductor 31A, which has the lowest bending resistance, breaks, there is still some margin for actual breakage of the target electric wire 2, but a less imminent sign of a break is detected, indicating that the target electric wire 2 may eventually break. When the third detection conductor 31C breaks in addition to the first detection conductor 31A, it is detected that the imminence of a break in the target electric wire 2 is increasing. Furthermore, when the second detection conductor 31B breaks in addition to the first detection conductor 31A and the third detection conductor 31C, it is detected that the imminence of a break in the target electric wire 2 is further increasing, and it is detected that a break is imminent. In this way, by being able to detect the imminence of a break in the target electric wire 2 in stages, it is possible to take measures according to the urgency at each stage. Alternatively, when the above-mentioned cable 1 includes multiple target electric wires 2 with different bending resistance, such as the power supply wires 2A, 2B and signal wires 2C, 2D, signs of a break in a target electric wire 2 with low bending resistance, such as the signal wires 2C, 2D, can be detected by a break in a detection line conductor 31 with low bending resistance among the multiple detection line conductors 31, and signs of a break in a target electric wire 2 with high bending resistance, such as the power supply wires 2A, 2B, can be detected by a break in a detection line conductor 31 with high bending resistance among the multiple detection line conductors 31.

[0044] The number of types of detection line conductors 31 with different bending resistance to be included in the cable 1 may be determined appropriately according to the number of levels of imminent disconnection of the target electric wire 2 that is to be detected. As listed above, various methods can be considered for changing the bending resistance of the detection line conductor 31, such as changing the number, diameter, or constituent material of the strands that make up the detection line conductor 31 as a stranded conductor. However, when providing a detection line conductor 31 with three levels of bending resistance, a preferred form is one in which the detection line conductor 31 is made of strands 33 made of a first metal material with low bending strength and strands 34 made of a second metal material with higher bending strength than the first metal material, as described above. In addition to the first detection line conductor 31A, which is composed only of wires 33 made of the first metallic material, and the second detection line conductor 31B, which is composed only of wires 34 made of the second metallic material, a third detection line conductor 31C, which includes both wires 33 made of the first metallic material and wires 34 made of the second metallic material, can be constructed. This allows three types of detection line conductors 31 with three levels of bending resistance to be prepared with a simple configuration using only wires 33, 34 made of two metallic materials. The degree of bending resistance can also be adjusted by changing the ratio of the number of wires 33, 34 made of the two metallic materials. Even when setting four or more levels of bending resistance, varying the number of wires 33, 34 made of the two metallic materials allows the detection line conductors 31 to have a variety of bending resistance.

[0045] The cable 1 with anomaly sign detection function according to this embodiment can detect signs of disconnection of the target electric wire 2 beforehand by breakage of the detection wire 3, and can be used in a variety of applications where disconnection of the target electric wire 2 is possible. It is particularly suitable for use in devices such as automobiles where the electric wire is frequently bent or vibrated due to movement. In particular, it can be suitably used in applications such as automobile brake systems where the impact of disconnection of the target electric wire 2 is significant and it is therefore important to detect disconnection of the target electric wire 2 beforehand.

[0046] (3) Electric wire abnormality detection device As described above, in the cable 1 with anomaly sign detection function according to this embodiment, signs of a break in the wire conductor 21 of the target electric wire 2 can be detected by detecting a break in the detection line conductor 31 that constitutes the detection line 3. The specific measurement method for detecting a break in the detection line conductor 31 and the specific configuration of the detection device for detecting a break in the detection line conductor 31 and recognizing and notifying the break as a sign of a break in the target electric wire 2 are not particularly limited. However, the electric wire anomaly sign detection device (hereinafter sometimes simply referred to as the detection device) according to one embodiment of the present disclosure described below can be suitably applied.

[0047] Fig. 2 schematically shows the configuration of an electric wire abnormality detection device 9 according to one embodiment of the present disclosure. The detection device 9 detects signs of a break in the electric wire conductor 21 of the target electric wire 2 as a sign of an electric wire abnormality in the cable 1 with an abnormality sign detection function according to the first embodiment of the present disclosure described above. For simplicity, Fig. 2 shows only one electric wire conductor 21 of the target electric wire 2 and one detection wire conductor 31 of the detection wire 3 as components of the cable 1, and shows a state in which a break B has occurred in the detection wire conductor 31.

[0048] The detection device 9 includes a measurement unit 91 and a notification unit 92. The measurement unit 91 measures the characteristic impedance of the detection line conductor 31 of the detection line 3 in the cable 1 with anomaly sign detection function to check whether a break B has occurred in the detection line conductor 31. The characteristic impedance is measured by inputting an inspection signal containing an AC component to the detection line conductor 31 and detecting a response signal using a reflection or transmission method. If a break B exists in the detection line conductor 31, the inspection signal is reflected at the break B, resulting in a discontinuous change in the response signal. Therefore, if the characteristic impedance measured by the measurement unit 91 changes by a reference value or more, it can be determined that a break B has occurred in the detection line conductor 31 and that a sign of a break has occurred in the electric wire conductor 21 of the target electric wire 2. The reference value may be determined in advance as a threshold value for the amount of change that should be considered to be due to a break in the detection line conductor 31, based on actual measurement results when no break B has occurred in the detection line conductor 31. As in the embodiment described above, when the cable 1 includes multiple detection conductors 31 with different bending resistance, measuring the characteristic impedance for each detection conductor 31 makes it possible to identify which detection conductor 31 has the break B and to detect signs of a disconnection in the target electric wire 2 in stages. Note that changes in characteristic impedance also occur due to damage to the detection conductor 31 that does not result in a break. In this specification, changes in characteristic impedance due to a break are treated as representative, but damage to the detection conductor 31 other than a break can also be used to detect signs of a disconnection in the target electric wire 2 via changes in characteristic impedance.

[0049] The detection of a break B in the detection conductor 31 can be performed not only by measuring the characteristic impedance but also by other electrical measurements, such as measuring resistance. However, using characteristic impedance measurement allows for highly sensitive detection of a break B in the detection conductor 31. In particular, when measuring the characteristic impedance using the reflection method, the characteristic impedance can be measured without connecting a measuring device to both ends of the cable 1, as long as the measurement unit 91 is connected to only one end, as shown in Figure 2. Therefore, even if the cable 1 is located in an inaccessible location, such as inside a vehicle, or has a complex route, as long as the measurement unit 91 is connected to only one end of the detection conductor 31, signs of a break in the target electric wire 2 can be detected without removing the electric wire or removing obstacles. Furthermore, measuring the characteristic impedance of the detection conductor 31 using the time domain reflectometry (TDR) method can not only determine whether or not a break B exists in the detection conductor 31, but also identify the location of the break B. The characteristic impedance may be measured between the sensing line conductor 31 of interest and earth potential, or between another sensing line conductor 31 or one of the electric line conductors 21.

[0050] The notification unit 92 receives a signal from the measurement unit 91. When the measurement unit 91 determines that the characteristic impedance of the detection conductor 31 has changed by a reference value or more and that a break has occurred in the detection conductor 31, the notification unit 92 notifies the outside that there is a sign of a break in the target electric wire 2, i.e., that there is a sign of a break in the electric wire conductor 21 of the target electric wire 2. The specific method of notifying the outside is not particularly limited, but examples include a method of providing a visual notification using a display panel 93 on a device, such as an automobile, in which the cable 1 is installed, or a method of notifying by an audible alarm. Alternatively, the notification unit 92 may be provided as an interlock device that restricts some or all of the functions of the device. If the cable 1 includes multiple detection conductors 31 with different bending resistances, the notification unit 92 issues different notifications depending on which of the detection conductors 31 has broken B, thereby enabling the notification of the sign of a break in the target electric wire 2 to be graded according to the urgency of the break.

[0051] In an apparatus in which a cable 1 is installed, such as an automobile, it is preferable to connect the above-described detection device 9 to the cable 1 at all times and continuously measure the characteristic impedance using the measurement unit 91 to constantly monitor whether or not there are signs of a disconnection in the target electric wire 2. In this way, if a sign of a disconnection in the target electric wire 2 occurs, the sign can be discovered early and notified to the user of the apparatus via the notification unit 92. The user who receives the notification can take measures such as replacing the cable 1 early, allowing the apparatus to be used for a long time without any malfunctions. In cases where the possibility or frequency of a disconnection in the target electric wire 2 is low, instead of constantly monitoring for signs of a disconnection in the target electric wire 2 using the detection device 9, the detection device 9 may be connected to the cable 1 only at specified times, such as during periodic inspections of the apparatus in which the cable 1 is installed, to check whether or not there are signs of a disconnection in the target electric wire 2.

[0052] Second Embodiment In the first embodiment described above, the breakage of the detection wire conductor 31 of the detection wire 3 is used as an indicator to detect signs of wire breakage due to accumulated metal fatigue in the wire conductor 21 of the target electric wire 2. However, electric wires can be damaged by causes other than conductor breakage due to metal fatigue. For example, while conductor breakage due to metal fatigue progresses over a long period of time due to repeated bending and vibration, a conductor breakage can also occur when the electric wire is suddenly subjected to a large impact due to an external force, etc. Furthermore, contact or friction with an external object can cause external damage to the electric wire, which can lead to breakage of the insulating coating or even the conductor. While the detection method using the breakage of the detection wire 31 described in the first embodiment can sensitively detect signs of wire conductor breakage due to metal fatigue, it does not necessarily sensitively detect signs of wire conductor breakage due to a sudden impact or signs of external damage to the target electric wire 2 due to contact or friction with an external object. Therefore, in the cables 1' and 1" with anomaly sign detection function according to the second and third embodiments described below, an outer detection layer is provided in addition to the detection wire 3 so that signs of damage to the target electric wire 2 caused by such impacts or external injuries can be detected together with signs of disconnection due to metal fatigue.

[0053] As will be described in detail later, in the second embodiment, the outer detection layer is configured as a conductive tape 7 shown in FIGS. 3A and 3B, and in the third embodiment, it is configured as a laminated tape 8 shown in FIGS. 4A to 4C. These outer detection layers are configured as layered members including a conductive material and are disposed between the sheath 5 and the group of electric wires G. In the illustrated embodiment, the outer detection layers 7 and 8 are disposed on the outer periphery of the tape layer 4, but they may also be disposed inside the tape layer 4, i.e., in a location that contacts the group of electric wires G. In either case, the assembly of the outer detection layer and the tape layer 4 is considered to be the inner circumferential layer, and the sheath 5 is formed as an extrusion molded body that is in close contact with the surface of this assembly. Note that even if the outer detection layer is disposed on the outer periphery of the sheath 5, the purpose of detecting signs of damage to the target electric wire 2 can be achieved. However, the outer detection layer is disposed inside the sheath 5 from the viewpoint of protecting the outer detection layer from the external environment so that accurate damage detection can be continued.

[0054] Since the outer detection layer is disposed further outward than the detection wire 3 with respect to the center of the cables 1', 1" with respect to the center of the cables 1', 1", when the cables 1', 1" are subjected to a sudden, large impact due to an external force or when they come into contact with or are rubbed against an external object, the outer detection layer is more likely to receive a larger load and break than the detection wire 3. Therefore, by detecting a break in the outer detection layer, it is possible to sensitively detect the occurrence of signs of damage to the target electric wire 2 due to an impact or external injury. The outer detection layer is not limited to the conductive tape 7 or laminated tape 8 described later, and is not limited to a specific form as long as it has a conductive member. However, it is preferable that the conductive member included in the outer detection layer is configured as a metal layer having a thickness smaller than the outer diameter of the detection wire conductor 31 of the detection wire 3 (the metal layers 7, 82 are shown thicker in Figures 3B and 4C for ease of understanding). In this way, even when a sudden impact that does not break the detection wire 3 is applied, or when the detection wire 3 comes into contact with or is rubbed against an external object, the conductive material of the outer detection layer is likely to break, and the outer detection layer can sensitively detect signs of damage to the target electric wire 2 that cannot be detected by the detection wire 3 alone.

[0055] Below, as second and third embodiments of the present disclosure, specific examples of cables 1', 1" with anomaly sign detection function that have outer detection layers 7, 8 in addition to a detection wire 3, and an electric wire anomaly sign detection device that targets these cables 1', 1" with anomaly sign detection function will be described. The cables 1', 1" with anomaly sign detection function according to the second and third embodiments have the same configuration as the cable 1 with anomaly sign detection function according to the first embodiment described in detail above, except for the outer detection layers 7, 8, and therefore descriptions of the configuration common to the cable 1 with anomaly sign detection function and electric wire anomaly sign detection device 9 according to the first embodiment will be omitted.

[0056] 3A and 3B show the configuration of a cable 1' with anomaly sign detection function according to a second embodiment of the present disclosure. Fig. 3A is a perspective view omitting the sheath 5, and Fig. 3B is a cross-sectional view taken perpendicular to the axial direction and including the sheath 5. The cable 1' has an outer detection layer 7 made of conductive tape around the outer periphery of the tape layer 4.

[0057] The conductive tape 7 is configured as a conductive tape body. The conductive tape 7 is wound around the outer periphery of the group of electric wires G, which is bound together by the insulating tape layer 4, in a spiral shape centered on the group of electric wires G along the axial direction of the group of electric wires G. The conductive tape 7 is wound loosely in the spiral shape, leaving gaps S between adjacent turns that are not occupied by the conductive tape 7. In the gaps S between the turns, the insulating tape layer 4 wound around the group of electric wires G is exposed and not covered by the conductive tape 7.

[0058] The conductive tape 7 may be made of any material as long as it contains a conductive material, but preferably contains a metal layer as the conductive material. In this case, the conductive tape 7 may be formed in the form of a metal foil made entirely of a metal material, or a substrate having a metal layer formed on its surface. When a substrate is used, the substrate itself may be made of an insulating material such as an organic polymer material, as long as a metal layer is formed on at least the surface of the substrate that faces outward when wrapped around the group of electric wires G. As described above, the thickness of the conductive material layer constituting the conductive tape 7 is preferably smaller than the diameter of each detection line conductor 31.

[0059] If the cable 1' receives a sudden, large impact due to the application of a sudden external force, or if the cable 1' receives external damage that breaks the sheath 5 due to contact or friction with an external object, the conductive tape 7 may break. Because the conductive tape 7 is located outside the target electric wire 2, even if the target electric wire 2 is not immediately damaged by the impact or external damage, the conductive tape 7 may break. In this case, the target electric wire 2 may also be subjected to a load that may lead to a break in the wire conductor 21 due to the impact, or to damage to the wire coating 22 or the wire conductor 21 due to the external damage. Therefore, by detecting the break in the conductive tape 7, it is possible to detect the occurrence of a precursor to damage to the target electric wire 2 due to the application of a load to the target electric wire 2.

[0060] In the cable 1' according to this embodiment, a break in the detection wire 3 can detect signs of disconnection of the target electric wire 2, which is mainly caused by metal fatigue, and a break in the conductive tape 7 provided as the outer detection layer can detect signs of damage to the target electric wire 2, which is caused by impact or external injury. In this way, by providing both the detection wire 3 and the outer detection layer 7 in the cable 1', it is possible to detect signs of various types of damage to the target electric wire 2, compared to the cable 1 according to the first embodiment, which is provided with only the detection wire 3.

[0061] Similar to the breakage of the detection line conductor 31, a breakage of the conductive tape 7 is preferably detected by characteristic impedance measurement, particularly by the reflection method. When a breakage occurs in the conductive tape 7, a discontinuous change in the characteristic impedance occurs due to the reflection of the inspection signal. The characteristic impedance of the conductive tape 7 can be measured between the conductive tape 7 and ground potential, or between the detection line conductor 31 or one of the electric wire conductors 21. Similarly to the detection line conductor 31, measuring the characteristic impedance of the conductive tape 7 using the TDR method can not only determine the presence or absence of a breakage but also pinpoint the location of the breakage. Note that a change in the characteristic impedance of the conductive tape 7 can also occur due to damage to the conductive tape 7 that does not result in a breakage. While this specification focuses on a change in characteristic impedance due to a breakage of the conductive tape 7, damage to the conductive tape 7 other than a breakage can also be used to detect signs of damage to the target electric wire 2 through changes in characteristic impedance.

[0062] The conductive tape 7 as the outer detection layer may be arranged in any manner as long as it surrounds the group of electric wires G. However, as described above, by being wound in a spiral shape with gaps S between the turns, changes in the characteristic impedance due to breakage can be detected more sensitively than when the conductive tape 7 surrounds the entire outer periphery of the group of electric wires G, such as in a spiral shape without gaps S between the turns. This is because when the conductive tape 7 is broken due to external damage or the like, the rate of change in the area of ​​the region covered by the conductive tape 7 (the rate of change based on the state before the breakage) increases in the cross section at each position along the axial direction of the cable 1′, resulting in a larger rate of change in the characteristic impedance. The size of the gaps S may be, for example, such that the area ratio of the region not covered by the conductive tape 7 and exposed as the gaps S is 50% or more. In addition, in order to be able to sensitively detect breakage of the conductive tape 7 due to external damage, etc., regardless of the position along the axial direction of the cable 1', it is preferable to set the spiral pitch so that the length of the expected external damage along the axial direction is sufficiently long compared to the pitch of the spiral shape of the conductive tape 7.

[0063] In this configuration, when the cable 1' includes the detection wire 3 and a conductive tape 7 layer as an outer detection layer, the electric wire abnormality detection device 9 can be configured to measure the characteristic impedance of the detection wire conductor 31 as well as the characteristic impedance of the conductive tape 7 constituting the outer detection layer in order to detect signs of damage to the target electric wire 2. When a change in the characteristic impedance of the conductive tape 7 exceeds a reference value, it is determined that a break has occurred in the conductive tape 7 and that a sign of damage has occurred in the target electric wire 2. The reference value may be predetermined as a threshold value for the amount of change that should be considered to be due to a break in the conductive tape 7, based on actual measurement results when no break has occurred in the conductive tape 7. The measuring devices constituting the measuring device 91 may be a device for measuring the characteristic impedance of the detection wire conductor 31 and a device for measuring the characteristic impedance of the outer detection layer 7, which may be provided separately or as a single device.

[0064] The notification unit 92 notifies the presence of a sign of damage to the target electric wire 2 when a change in the characteristic impedance of the detection line conductor 31 equals or exceeds a reference value as measured by the measurement unit 91. Furthermore, the notification unit 92 also notifies the outside of the presence of a sign of damage to the target electric wire 2 when a change in the characteristic impedance of the conductive tape 7 constituting the outer detection layer equals or exceeds a reference value. As described above, a change in the characteristic impedance of the detection line conductor 31 can sensitively detect a sign of a disconnection of the wire conductor 21 of the target electric wire 2 due to metal fatigue, whereas a change in the characteristic impedance of the outer detection layer 7 can sensitively detect a sign of damage to the wire conductor 21 or wire coating 22 of the target electric wire 2 due to the application of a sudden impact or the formation of external damage. Therefore, it is preferable that the notification unit 92 issue different notifications when the change in the characteristic impedance of the detection line conductor 31 equals or exceeds a reference value and when the change in the characteristic impedance of the outer detection layer 7 equals or exceeds a reference value, so that the two types of notifications can be distinguished. This allows the user to identify the type of damage that is predicted to occur in the detection line conductor 31 and its cause.

[0065] <Third embodiment> Next, a third embodiment of the present disclosure will be described, in which an outer detection layer is formed using a laminated tape 8 instead of the conductive tape 7 of the second embodiment. Descriptions of configurations common to the second embodiment will be omitted.

[0066] 4A and 4B show the configuration of a cable 1" with anomaly sign detection function according to a third embodiment of the present disclosure. FIG. 4A is a perspective view with the sheath 5 omitted, and FIG. 4B is a cross-sectional view showing a section cut perpendicular to the axial direction, including the sheath 5. The cable 1" according to the third embodiment has an outer detection layer made of a laminated tape 8 on the outer periphery of a group of electric wires G held together by a tape layer 4. The laminated tape 8 may be arranged in any manner as long as it is arranged to surround the group of electric wires G, but in the manner shown, it is wound in a spiral shape around the group of electric wires G. The spiral shape of the laminated tape 8 may or may not have gaps between the turns of the spiral.

[0067] As shown in the cross-sectional view (cross-section perpendicular to the longitudinal direction of the tape) in FIG. 4C , the laminated tape 8 is configured by forming conductive coating layers 82, 82 on both sides of a substrate 81 made of a tape-shaped insulator or semiconductor. In the laminated tape 8, the coating layers 82, 82 formed on both sides function as the conductive members of the outer detection layer. In the laminated tape 8, the constituent material of the substrate 81 is not particularly limited as long as it is an insulator or semiconductor. However, from the viewpoint of ensuring flexibility and thickness, it is particularly preferable to form it from an insulating nonwoven fabric tape. The constituent material of the coating layers 82, 82 is also not particularly limited as long as it is a conductive material. However, metals such as copper or copper alloy, aluminum or aluminum alloy can be suitably used. An adhesive tape 83 can be provided on one side of the coating layer 82 as needed. The adhesive tape 83 can be used to secure the laminated tape 8 in a state where it is wrapped around the outer circumference of the cable 1″.

[0068] In the cable 1" according to the third embodiment, if a large impact is suddenly applied or if external damage occurs due to contact or friction with an external object, damage may occur to the laminated tape 8. By detecting such damage to the laminated tape 8, it is possible to detect signs of damage to the target electric wire 2 due to the application of an impact or external damage. Damage to the laminated tape 8 can be detected by measuring the characteristic impedance between the two conductive coating layers 82, 82. When no damage is formed in the laminated tape 8, the two coating layers 82, 82 are insulated from each other by the substrate 81. In this state, the laminated tape 8 is surrounded by a conductive continuum, each of which exists along the longitudinal direction of the laminated tape 8 and has a conductance determined by the materials and thicknesses of the substrate 81 and the coating layers 82, 82. If at least one of the two coating layers 82, 82 breaks due to a fracture in the laminated tape 8, or if the two coating layers 82, 82 are short-circuited to each other due to penetration of a conductive material into the laminated tape 8 or compression of the laminated tape 8, the conductance between the two coating layers 82, 82 will change. This change in conductance component is observed as a change in the characteristic impedance between the two coating layers 82, 82.

[0069] In the electric wire abnormality detection device 9 for the cable 1" according to the third embodiment, the measuring unit 91 monitors the characteristic impedance of the detection conductor 31 and also monitors the characteristic impedance between the two coating layers 82, 82 of the laminated tape 8 that constitute the outer detection layer. The notification unit 92 not only monitors the characteristic impedance of the detection conductor 31 when a change of equal to or greater than a reference value occurs in the characteristic impedance between the two coating layers 82, 82 of the laminated tape 8, but also notifies the outside that a sign of damage has occurred in the target electric wire 2, distinguishing between the two cases as appropriate.

[0070] Furthermore, the sensitivity of damage detection can be further improved by configuring the substrate 81 of the laminated tape 8 as a semiconductor and monitoring the characteristic impedance between the two coating layers 82, 82 while applying a low voltage between them that is low enough not to cause a short circuit via the substrate 81. This is because when the laminated tape 8 is subjected to an external force such as compression, even if the external force is not strong enough to cause a short circuit due to physical contact between the two coating layers 82, 82, a short circuit may occur between the two coating layers 82, 82 due to dielectric breakdown, which may be detected as a change in characteristic impedance.

[0071] Although the embodiments of the present disclosure have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0072] 1,1',1" (with abnormality detection function) cable 2. Target wires 2A,2B feeder line 2C,2D signal line 21(21A~21D) Electrical Wire Conductor 22 Wire coating 3 Detection line 3A First detection line 3B Second detection line 3C Third detection line 31 Detection line conductor 31A First sensing line conductor 31B Second sensing line conductor 31C Third sensing line conductor 32 Detection wire coating 33. Wire of first metallic material 34 Second metallic material wire 4 tape layers 5 Sheath 51 Outer layer 52 Inner layer 7 Conductive tape (outer detection layer) 8 Laminated tape (outer detection layer) 81 Base material 82 Covering layer 83 Adhesive Tape 9 (Electric wire abnormality prediction) detection device 91 Measurement section 92 Notification Department 93 Display Panel B. Breakage of the detection line conductor G wire group S gap

Claims

1. One or more target electric wires having an electric wire conductor and an electric wire coating that covers the outer periphery of the electric wire conductor; a plurality of detection wires each having a detection wire conductor and a detection wire coating that coats the outer periphery of the detection wire conductor, the detection wire conductors having different bending resistances; a sheath that covers an outer periphery of a group of electric wires including the target electric wire and the detection wire, The detection line conductor has lower bending resistance than the electric wire conductor, the sheath is formed as an extrusion molded body that is in direct contact with an outer periphery of the electric wire group or that is in close contact with a surface of an inner periphery layer that is in close contact with the outer periphery of the electric wire group and that covers the electric wire group, the plurality of sense lines include a first sense line having a first sense line conductor and a second sense line having a second sense line conductor; the first detection wire conductor is made of a plurality of wires made of a first metallic material, and the outer periphery of the plurality of wires is collectively covered directly with the detection wire covering; The second detection line conductor is made of multiple strands of a second metal material that has higher bending resistance than the first metal material, and the outer periphery of the multiple strands is directly covered with the detection line covering. This is a cable with an abnormality sign detection function.

2. the plurality of sense lines further includes a third sense line having a third sense line conductor; The third sensing line conductor is The sensing wire conductor includes both a wire made of the first metal material and a wire made of the second metal material, and has a bending resistance higher than that of the first sensing wire conductor and lower than that of the second sensing wire conductor; 2. The cable with anomaly sign detection function according to claim 1, wherein the outer periphery of the wires of the first metallic material and the wires of the second metallic material are collectively covered directly with the detection wire covering.

3. A plurality of the target electric wires are included, 3. The cable with anomaly sign detection function according to claim 1, wherein the plurality of target electric wires are arranged surrounding the detection wire.

4. A cable with an abnormality precursor detection function as described in any one of claims 1 to 3, having an outer detection layer as a layered member containing a conductive material between the sheath and the group of electric wires.

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