Sensor wire, sensor device, and wire harness

Abstract

Provided are: a sensor wire which is a member capable of sensitively detecting mechanical deformation and environmental changes; a sensor device provided with such a sensor wire; and a wire harness. A sensor wire (1) has a first insulated wire (12a) and a second insulated wire (12b) each provided with a conductor and an insulating coating covering the outer periphery of the conductor, and the first insulated wire (12a) and the second insulated wire (12b) are bent and assembled in a state in which the longitudinal axes coincide with each other to constitute a wire assembly (11). A group of the first insulated electric wires (12a) and the second insulated electric wires (12b) is used as a unit, and a region in which the first insulated electric wires (12a) and the second insulated electric wires (12b) are alternately arranged in a plurality of units is arranged on a straight line (B) crossing the electric wire assembly (11).

Description

Technical Field

[0001] This disclosure relates to sensor wires, sensor devices, and wire harnesses. Background Technology

[0002] Wires are installed or laid in various electrical / electronic equipment, conveying equipment, buildings, public facilities, etc., but they sometimes become damaged with long-term use. To avoid serious impacts on wire performance due to damage, it is desirable to detect damage early and sensitively. One method for detecting wire damage involves attaching a component to the wire beforehand, which functions as a sensor to detect damage, and then checking the wire for damage using this component. For example, Patent Document 1 discloses a wire with a conductive strip or laminated strip disposed around the periphery of a core wire having a conductor and an insulating sheath. The conductive strip is wound into a spiral shape along the axial direction of the core wire on the surface of the insulating sheath, with gaps not occupied by the conductive strip between the spiral turns. The laminated strip has a substrate configured as a strip-shaped insulator or semiconductor and conductive sheathing layers formed on both sides of the substrate. When external damage occurs in a wire, the characteristic impedance between the conductive strip and the conductor that makes up the core changes due to the damage to the conductive strip, and the characteristic impedance between the two cladding layers contained in the laminated strip changes due to the damage to the laminated strip, thus enabling sensitive detection of the formation of external damage in the wire.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-162449 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] If a component whose electrical properties change upon damage, such as the conductive strip or laminated strip used in Patent Document 1, is attached to the wire, the occurrence of damage caused by external factors can be sensitively detected. However, even before irreversible damage occurs, wires are frequently subjected to deformation caused by mechanical loads and changes in the surrounding environment. These mechanical deformations and environmental changes may alter the operation and characteristics of the wire, potentially causing the wire itself and the connected equipment to malfunction. Furthermore, if the effects of mechanical deformation and environmental changes accumulate in the wire, they may lead to future damage or deterioration. To avoid these situations, it is desirable to be able to sensitively detect mechanical deformations and environmental changes in the wire that do not immediately cause damage or deterioration.

[0008] In view of the above, the objective is to provide a sensor wire that can sensitively detect mechanical deformation and environmental changes, a sensor device and a wire harness having such a sensor wire.

[0009] Methods for solving problems

[0010] The sensor wire disclosed herein has a first insulated wire and a second insulated wire. The first insulated wire and the second insulated wire each have a conductor and an insulating covering the outer periphery of the conductor. The first insulated wire and the second insulated wire are bent and assembled in a state where their longitudinal axes are aligned with each other to form a wire assembly. The group of the first insulated wire and the second insulated wire is regarded as one unit. There is a region on a straight line that runs through the wire assembly with multiple units of the first insulated wire and the second insulated wire arranged alternately.

[0011] The sensor device disclosed herein includes: the sensor wire; and a monitoring unit that inputs differential signals to the first insulated wire and the second insulated wire constituting the sensor wire to obtain a response signal, and monitors changes in the response signal.

[0012] The wire harness disclosed herein comprises: a target wire, consisting of at least one wire; and the sensor device, wherein the sensor wire constituting the sensor device is arranged along the length direction of the target wire in at least a portion of the region.

[0013] Invention Effects

[0014] The sensor wires, sensor devices, and wiring harnesses disclosed herein serve as components capable of sensitively detecting mechanical deformation and environmental changes, and are sensor devices and wiring harnesses equipped with such sensor wires. Attached Figure Description

[0015] Figure 1 Figure (1A) is a perspective view of a spiral-type sensor wire as an example of a sensor wire according to an embodiment of the present disclosure. Figure 1 Figure (1B) is a perspective view of a coil-type sensor wire as another example of a sensor wire according to an embodiment of the present disclosure.

[0016] Figure 2 Figure (2A) is a schematic diagram showing the structure of a sensor device according to an embodiment of the present disclosure. Figure (2B) is a perspective view showing the structure of a wire harness according to an embodiment of the present disclosure.

[0017] Figure 3Figures (3A) and (3B) are schematic cross-sectional views showing the state changes when a force is applied to an assembly of wires in a direction that causes the distance between the wires to move away. Figure (3A) shows the state before the force is applied, and Figure (3B) shows the state after the force is applied.

[0018] Figure 4 Figures (4A) and (4B) are schematic cross-sectional views showing the state changes when a liquid comes into contact with an electrical wire assembly. Figure (4A) shows the state before contact with the liquid, and Figure (4B) shows the state after contact with the liquid.

[0019] Figure 5 Figures (5A) and (5B) are schematic cross-sectional views showing the state changes of the material connected to the wire assembly during melting. Figure (5A) shows the state before melting, and Figure (5B) shows the state after melting.

[0020] Figure 6 Figures (6A) and (6B) are schematic cross-sectional views showing the state changes of the material connected to the wire assembly due to chemical changes. Figure (6A) shows the state with a low dielectric constant before the chemical change, and Figure (6B) shows the state with a high dielectric constant after the chemical change.

[0021] Figure 7 This is a measurement result showing the change in the reflection coefficient associated with the elongation of the coil-type sensor wire.

[0022] Figure 8 This shows the measurement results of the change in reflection coefficient associated with the bending of the coil-type sensor wire.

[0023] Figure 9 This is a measurement result showing the change in the reflection coefficient associated with the elongation caused by heating of the coil-type sensor wire.

[0024] Figure 10 The results show the measurement results of the change in the reflection coefficient associated with the contact of the electrolyte solution with the vortex-type sensor wire.

[0025] Figure 11 This shows the measurement results of the change in reflection coefficient associated with contact between the finger and the spiral-shaped sensor wire.

[0026] Figure 12 The results show the measurement results of the change in reflection coefficient associated with contact with two types of rubber-coiled sensor wires. Detailed Implementation

[0027] [Description of embodiments of this disclosure]

[0028] First, the embodiments of this disclosure will be described.

[0029] [1] The sensor wire of this disclosure has a first insulated wire and a second insulated wire. The first insulated wire and the second insulated wire each have a conductor and an insulating covering the outer periphery of the conductor. The first insulated wire and the second insulated wire are bent and assembled in a state where their length axes are aligned with each other to form a wire assembly. The group of the first insulated wire and the second insulated wire is taken as one unit. There is a region on a straight line that runs through the wire assembly where multiple units of the first insulated wire and the second insulated wire are arranged alternately.

[0030] The aforementioned sensor wires sensitively detect mechanical deformation and environmental changes applied to them and output them as electrical signals. Specifically, if a differential signal is input to the two insulated wires constituting the wire assembly, and response signals such as characteristic impedance are obtained, these response signals can reflect changes in the mechanical deformation and environmental changes applied to the sensor wires. This is because, in a structure where two insulated wires are alternately arranged in a straight line traversing the wire assembly, an electric field is generated between adjacent insulated wires. The state of this electric field changes with the distance between the insulated wires caused by the deformation of the wire assembly and with the change in the dielectric constant of the material surrounding the wire assembly. This change in the state of the electric field also imparts a change to the response signals such as characteristic impedance. Therefore, if sensor wires are pre-positioned along the path of the object wire whose mechanical deformation and environmental changes are to be monitored, and a check signal is input to the sensor wires and the response signal is detected, then when mechanical deformation and environmental changes are applied to the object wire and the assembly of sensor wires, these mechanical deformations and environmental changes can be sensitively detected as changes in the response signals. In addition, in devices used with the target wire, the device can also be constructed in such a way that it receives external indications and information by utilizing the mechanical deformation of the sensor wire and changes in the environment, and reads the input indications and information by the changes in the response signal in the sensor wire.

[0031] Here, in the sensor wire, two insulated wires are bent together with their length axes aligned, forming a wire assembly. This allows for more sensitive detection of mechanical deformation and environmental changes as changes in the response signal, compared to two insulated wires running straight parallel. This is because a relatively long insulated wire is housed within a defined length range, enabling the entire length of the assembly to be used as a sensor, and allowing for significant deformation due to variations in the shape of the wire assembly. Furthermore, the insulated wires are bent into specific shapes (vortex, spiral), so that when an AC signal is input, a magnetic field is generated if observed on a per-wire basis. However, since the two insulated wires are aligned with their length axes, and the input signals are differential signals with opposite polarities, the magnetic fields generated by the two wires cancel each other out. Therefore, the magnetic field is less likely to affect the sensor wire's detection results or the movement of the target wire.

[0032] [2] In the manner described in [1] above, the first insulated wire and the second insulated wire can be wound around a common central axis to form the wire assembly. In this case, a wire assembly formed by densely clustering two insulated wires can be easily obtained. By densely clustering two insulated wires with their longitudinal axes aligned with each other, and repeating the structure of alternating arrangement of the two insulated wires multiple times, a wire assembly that exhibits a large change in response signal when subjected to mechanical deformation or environmental changes can be obtained.

[0033] [3] In the manner described in [1] or [2] above, the first insulated wire and the second insulated wire may be assembled into a planar shape in the wire assembly. In this case, when mechanical deformation or environmental changes occur at any part of the plane formed by the sensor wires, these phenomena can be detected as changes in response signals. Therefore, it is easy to monitor mechanical deformation and environmental changes over a wide range.

[0034] [4] In any of the methods described in [1] to [3] above, the first insulated wire and the second insulated wire may be wound into a spiral shape in the wire assembly. In this case, the two insulated wires can be densely clustered into a planar shape to form a wire assembly. Therefore, it becomes a sensor wire capable of detecting mechanical deformation and environmental changes with high sensitivity over a wide range.

[0035] [5] In any of the above [1] to [4] methods, the first insulated wire and the second insulated wire may be respectively configured as enameled wires. Thus, the insulation coating in the insulated wire can be thinned, reducing the distance between adjacent conductors in the wire assembly. Therefore, deformation of the wire assembly and changes in the dielectric constant of the material surrounding the wire assembly are easily reflected as changes in the electric field. As a result, mechanical deformation in the sensor wire and environmental changes can easily cause large changes in the response signal.

[0036] [6] In any of the embodiments described in [1] to [5] above, the sensor wire may further include a support member that contacts and supports the wire assembly. By using the support member, the sensor wire can be easily used as a self-supporting component. In addition, by using the support member, the wire assembly is less likely to deform under small mechanical loads such as minor vibrations, and mechanical loads that can be considered within the normal range can be ignored. The mechanical loads that should be detected as abnormal or intentionally applied mechanical loads can be selectively detected as changes in response signals.

[0037] [7] In the manner described in [6] above, the support member may have flexibility to deform with the deformation of the wire assembly. Thus, when an external force causing deformation is applied to the sensor wire, the sensor wire deforms, including the support member, and imparts a change to the response signal.

[0038] [8] In any of the methods described in [1] to [7] above, a dielectric element may be provided, which is connected to the wire assembly and contains a material whose dielectric constant changes due to changes in the environment surrounding the wire assembly. In this case, when the environment in which the sensor wires are placed changes, the response signal of the sensor wires changes due to the change in the dielectric constant in the region surrounding the wire assembly and the accompanying change in the state of the electric field. Then, the change in the environment can be detected based on the change in the response signal.

[0039] [9] In the manner described in [8] above, the change in dielectric constant may be caused by at least one of a phase transition and a chemical change in the dielectric material. By using a substance that undergoes such a phase transition or chemical change as the dielectric material, changes in the environment in which the sensor wire is placed can be sensitively detected as changes in the response signal of the sensor wire.

[0040]

[10] The sensor device of this disclosure includes: a sensor wire of any one of [1] to [7] above; and a monitoring unit that inputs a differential signal to the first insulated wire and the second insulated wire constituting the sensor wire to obtain a response signal and monitors changes in the response signal.

[0041] This sensor device obtains a response signal by inputting a differential signal to the sensor wires of the aforementioned wire assembly via a monitoring unit. When mechanical deformation or environmental changes occur on the sensor wires, the response signal changes sensitively due to changes in the state of the electric field surrounding the wire assembly. Therefore, the sensor device can be used as a detection device for detecting the application of mechanical loads and changes in the environment. For example, if the sensor wires constituting the sensor device are arranged along at least a portion of the object wire whose mechanical deformation or environmental changes are to be monitored, and the response signal is monitored, these phenomena can be sensitively detected when mechanical deformation or environmental changes occur on the object wire and the assembly of sensor wires. Since the wire assembly consists of two insulated wires, and a differential signal is input to this assembly, it is difficult for a magnetic field to be generated in the wire assembly due to the measurement of the monitoring unit.

[0042]

[11] In the manner described in

[10] above, if the response signal exhibits a change exceeding a reference, the monitoring unit determines that at least one of the following has been applied to the sensor wire: mechanical deformation, temperature change, or change in the contacting material. Mechanical deformation, temperature change, and change in the contacting material are all phenomena that impart a change to the response signal obtained in the sensor wire. By setting a predetermined reference for the change in the response signal, when a change exceeding this reference occurs in the response signal, it is determined that at least one of these phenomena has occurred. Thus, for example, when these phenomena occur to a degree exceeding a predetermined level, such as at a level that causes a non-negligible impact on the operation of the object wire where the sensor wire is placed nearby, or at a level that may cause irreversible changes in the object wire, it is possible to detect the situation and take countermeasures accordingly.

[0043]

[12] In the above schemes

[10] or

[11] , the monitoring unit may monitor the change in characteristic impedance or reflection coefficient between the first insulated wire and the second insulated wire constituting the sensor wire as the response signal. Characteristic impedance and reflection coefficient are parameters that sensitively reflect changes in the state of the electric field caused by mechanical deformation in the sensor wire and changes in the environment, and their values ​​may change. Therefore, in the sensor wire, by measuring the characteristic impedance or reflection coefficient, mechanical deformation and environmental changes in the sensor wire can be sensitively detected.

[0044]

[13] In the manner described in

[12] above, the monitoring unit may measure the characteristic impedance or reflection coefficient using a time-domain reflectometry or a frequency-domain reflectometry. By employing a time-domain reflectometry or a frequency-domain reflectometry, the region where the characteristic impedance or reflection coefficient changes on the response signal can be correlated with the position on the sensor wire through appropriate calculations, etc. Furthermore, this position corresponds to the location where the sensor wire undergoes mechanical deformation or environmental change. Therefore, the location where mechanical deformation or environmental change occurs in the sensor wire can be determined easily and with high accuracy.

[0045]

[14] In any of the methods described in

[10] to

[13] above, the wire assembly may be impedance matched with the monitoring unit by adjusting the number of groups of the first and second insulated wires arranged on the straight line. By impedance matching between the wire assembly and the monitoring unit, the effects of loss and noise can be reduced to obtain a response signal, and the mechanical deformation and environmental changes in the sensor wires can be detected with high precision. In the wire assembly, the characteristic impedance can be easily changed by adjusting the number of groups of alternately arranged insulated wires to achieve impedance matching with the monitoring unit.

[0046]

[15] The wire harness of this disclosure includes an object wire consisting of at least one wire and any one of the sensor devices described in

[10] to

[14] above, wherein the sensor wire constituting the sensor device is arranged along the length direction of the object wire in at least a portion of the region.

[0047] In this wiring harness, sensor wires comprising wire assemblies are arranged along the length of the target wire in at least a portion of the region. Therefore, when the assembly of the target wire and sensor wires undergoes mechanical deformation or environmental changes, these can be sensitively detected by the sensor device. This allows for the detection of mechanical deformation and environmental changes that affect the operation and characteristics of the target wire, enabling the consideration of their impact during the use of the target wire, or the implementation of measures such as replacing the target wire before irreversible damage or deterioration occurs due to mechanical deformation or environmental changes. Furthermore, if indications or information are input via applying mechanical deformation or environmental changes to the sensor wires, and these indications or information are read in response to changes in the signal, the sensor device can be used as an input unit in equipment used with the wiring harness.

[0048] [Details of the embodiments of this disclosure]

[0049] Hereinafter, the sensor wires, sensor devices, and wire harnesses according to embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. A sensor device is constituted by including the sensor wires of the embodiments of the present disclosure. Furthermore, a wire harness is constituted by including the sensor device. The sensor wires and sensor devices monitor mechanical deformation and environmental changes. In the wire harness, for object wires that become the objects of monitoring, the sensor device performs monitoring on them. In this specification, the terms used to describe the shape and arrangement of the constituent components of the wire, such as spiral, helical, or linear, include not only strictly geometric concepts but also allowable errors within the wire.

[0050] <A brief overview of the structure of sensor wires, sensor devices, and wiring harnesses>

[0051] First, a general description of the structure of the sensor wire, sensor device, and wiring harness according to the embodiments of this disclosure will be given. Figure 1 Figures (1A) and (1B) show examples of the structure of sensor wires according to embodiments of the present disclosure in perspective. Figure 1 Figures (1A) and (1B) represent different methods, respectively. Additionally, Figure 2 Figure (2A) schematically illustrates an example of the structure of a sensor device according to an embodiment of the present disclosure. Figure 2 Figure (2B) shows an example of the structure of a wire harness according to an embodiment of the present disclosure in a perspective view.

[0052] (1) Sensor wires

[0053] like Figure 1 As shown in Figures (1A) and (1B), a sensor wire 1 according to an embodiment of the present disclosure includes a wire assembly 11. The wire assembly 11 includes a pair of insulated wires, a first insulated wire 12a and a second insulated wire 12b. The first insulated wire 12a and the second insulated wire 12b each have a conductor 121 and an insulating cover 122 covering the outer periphery of the conductor 121 (see Figure 1A). Figure 3 (See Figure (3A)). The types of insulated wires 12a and 12b are not specifically specified, but they are preferably constructed as enameled wires.

[0054] In the wire assembly 11, a pair of insulated wires 12a and 12b are bent and assembled with their longitudinal axes aligned, forming the wire assembly 11. Furthermore, the wire assembly 11, taking the group of the first insulated wire 12a and the second insulated wire 12b as one unit, has a region on the reference line B, which runs across the wire assembly 11, where multiple units of the first insulated wire 12a and the second insulated wire 12b are alternately arranged. That is, as... Figure 3As shown in Figure (3A), the wire assembly 11 has a region in which, along a reference straight line B, a first insulated wire 12a → a second insulated wire 12b → a first insulated wire 12a → a second insulated wire 12b → … is formed, with multiple alternating arrangements of the first insulated wire 12a and the second insulated wire 12b. Preferably, this alternating arrangement is formed throughout the entire region of the wire assembly 11, except for the ends and periphery. In the wire assembly 11, a pair of insulated wires 12a and 12b are not fixed to each other by welding of the insulation cover 122, etc., and can move relative to each other.

[0055] The wire assembly 11 can be any shape formed by bending a pair of insulated wires 12a and 12b with their longitudinal axes aligned in the same direction, arranged in the alternating configuration described above. However, as a preferred example, such as Figure 1 As shown in Figure (1A), it is possible to construct the wire assembly 11 as a double-wire spiral wire 11A in which a pair of insulated wires 12a and 12b are assembled into a spiral shape, and to construct the sensor wire 1 as a spiral-type sensor wire 1A. Figure 2 In Figure (2A), the pair of insulated wires 12a and 12b constituting the double-wire spiral wire 11A are schematically represented by thick and thin lines. Additionally, as another example, such as... Figure 1 As shown in Figure (1B), the following configurations can be used: the wire assembly 11 is configured as a double-coil wire 11B consisting of a pair of insulated wires 12a and 12b wound into a spiral shape, and the sensor wire 1 is configured as a coil-type sensor wire 1B. In the double-coil wire 11A, if the reference line B is set as a radial line connecting the center of the spiral shape and a point on the outer periphery, an alternating arrangement is formed along the reference line B. In the double-coil wire 11B, if the reference line B is set as a line parallel to the central axis of the spiral shape, an alternating arrangement is formed along the reference line B. In addition to spiral and helical shapes, examples of shapes for the pair of insulated wires 12a and 12b in the wire assembly 11 include bending the pair of insulated wires 12a and 12b into a serrated shape, or arranging the pair of insulated wires 12a and 12b in a zigzag pattern and covering the entire surface.

[0056] If the wire assembly 11 is a planar assembly of a pair of insulated wires 12a and 12b, as in the case of the aforementioned double-wire spiral wire 11A, then mechanical deformation and environmental changes can be detected at any point on the surface formed by the wire assembly 11, and these changes can be monitored over a wide range, which is preferable. Furthermore, considering the ease of manufacturing the wire assembly 11 and the increased sensitivity to detecting mechanical deformation and environmental changes by densely packing the insulated wires 12a and 12b, the wire assembly 11 is preferably a pair of insulated wires 12a and 12b wound around a common central axis. In the case of the wire assembly 11 being a double-wire spiral wire 11A, the pair of insulated wires 12a and 12b are wound concentrically from the inside to the outside in a plane around the central axis. In the case of the wire assembly 11 being a double-wire coil wire 11B, the pair of insulated wires 12a and 12b are wound spirally from one side to the other along the central axis.

[0057] The sensor wire 1 also has an arbitrary support member 13. The support member 13 is a component that is grounded to and supports the wire assembly 11. Figure 1 In the spiral-type sensor wire 1A shown in Figure (1A), a plate-shaped support member 13 is provided, which supports the double-wire spiral wire 11A by surface contact with the surface formed by the double-wire spiral wire 11A. A shaft portion 131 protruding from the plate surface of the support member 13 is integrally provided at the center of the support member 13. This shaft portion 131 functions as a central axis for winding a pair of insulated wires 12a and 12b around the periphery. Furthermore, if a circular recess matching the size of the double-wire spiral wire 11A is formed on the plate surface of the support member 13, and the double-wire spiral wire 11A is received in this recess, the double-wire spiral wire 11A can be stably held. Figure 1 In the coil-type sensor wire 1B shown in Figure (1B), a rod-shaped support member 13 is provided. This support member 13 is inserted through the spiral-shaped hollow portion 111 of the double-wire coil wire 11B to support the double-wire coil wire 11B. This support member 13 serves as the core material of the double-wire coil wire 11B, that is, as the central axis around which a pair of insulated wires 12a and 12b are wound.

[0058] By having a support member 13, the sensor wire 1 can stably maintain the coiled shape of the bi-wire spiral wire 11A, the spiral shape of the bi-wire coil wire 11B, and the overall shape of the insulated wires 12a and 12b in the wire assembly 11, making it easy to treat the sensor wire 1 as a self-supporting component. Furthermore, by supporting the wire assembly 11 with the support member 13, the wire assembly 11 is less prone to deformation under small mechanical loads such as minor vibrations. The support member 13 is preferably made of a non-magnetic insulator, but the specific structure and material of the support member 13, as detailed below, are preferably selected based on the changes that should be detected by the sensor wire 1.

[0059] Furthermore, although not shown in the illustrations, the sensor wire 1 may also have a dielectric element grounded to the wire assembly 11. The dielectric element refers to a substance whose dielectric constant changes due to environmental changes in the area surrounding the wire assembly 11 (the area outside the wire assembly 11 and the internal space of the wire assembly 11, such as the hollow portion 111 of a bifilar coil). Environmental changes refer to changes in the temperature of the space where the sensor wire 1 is placed and changes in the surrounding substances. The shape of the dielectric element and its arrangement on the sensor wire 1 are not particularly limited. For example, in the case of a spiral-type sensor wire 1A, a arrangement in which a sheet-like dielectric element is in contact with at least one of the upper or lower surfaces of the bifilar spiral wire 11A can be cited. In the case of a coil-type sensor wire 1B, arrangements such as filling the hollow portion 111 of the bifilar coil wire 11B with a dielectric element, winding a sheet-like dielectric element around the outer periphery of the bifilar coil wire 11B, or embedding a tubular dielectric element can be cited. In some cases, the support member 13 may also function as a dielectric element. Specific types of dielectric elements will be described later.

[0060] (2) Sensor device

[0061] like Figure 2 As schematically shown in Figure (2A), a sensor device 2 according to an embodiment of the present disclosure includes the aforementioned sensor wire 1 and monitoring unit 21. Figure 2 Figure (2A) shows a method of using a spiral-type sensor wire 1A as the sensor wire 1. The monitoring unit 21 is a device that receives an AC check signal from the sensor wire 1 and monitors changes in that response signal. The check signal is a differential signal. That is, AC signals with opposite polarities are input to the insulated wires 12a and 12b. By inputting the differential signal to the wire assembly 11, insulated wires 12a and 12b carrying AC currents of opposite polarities are alternately arranged along the reference straight line B of the wire assembly 11 (see reference). Figure 3 Figure (3A)).

[0062] The monitoring unit 21 inputs a check signal consisting of a differential signal to the wire assembly 11 of the sensor wire 1. The characteristic impedance between a pair of insulated wires 12a and 12b can be appropriately used as the electrical parameter to be measured as a response signal. As explained in detail later, when the sensor wire 1 undergoes mechanical deformation or environmental changes (temperature changes, changes in the material it comes into contact with), the state of the electric field in the space surrounding the sensor wire 1 changes, and consequently, the value of the characteristic impedance changes. Therefore, in the sensor device 2, the value of the characteristic impedance as a response signal can be measured and monitored while the check signal is input, and the mechanical deformation and environmental changes in the sensor wire 1 can be detected based on the change in this value. In addition to the characteristic impedance, parameters that can be measured as a response signal include reflection coefficient, conductivity, and capacitance. These parameters are correlated with the characteristic impedance, reflecting changes in the state of the electric field in the space surrounding the sensor wire 1. Measuring the characteristic impedance or reflection coefficient as a response signal is preferred for its high sensitivity in detecting mechanical deformation and environmental changes.

[0063] The monitoring unit 21 can be composed of a measuring device capable of generating a differential signal as a check signal and detecting a response signal. For example, when measuring the characteristic impedance as a response signal, an impedance meter can be used. When obtaining the response signal through the monitoring unit 21, the measurement can be performed by either transmission or reflection. From the viewpoint of simplicity of measurement, the reflection method is preferred in that the response signal can be obtained by connecting the measuring device at only one end. When using the reflection method, the measuring device can be connected to one end of the wire assembly 11, and the terminating resistor 25 can be connected to the other end. In the sensor device 2, impedance matching can be performed between the monitoring unit 21 and the wire assembly 11 to suppress losses and noise in the response signal. In the wire assembly 11, impedance matching can be easily performed by adjusting the number of sets of two insulated wires 12a and 12b arranged along the reference straight line B. Regarding the number of sets of insulated wires 12a and 12b, in the case of double-wire spiral wire 11A, the number of times the two insulated wires 12a and 12b are wound into a spiral shape can be adjusted. In the case of double-wire coil wire 11B, the number of turns of the two insulated wires 12a and 12b in the spiral shape can be adjusted.

[0064] The sensor device 2 can be used independently as a device for detecting mechanical deformation and environmental changes. That is, by detecting the mechanical deformation and environmental changes applied to the sensor wire 1 itself, it can be used as a detection device for detecting mechanical loads generated in the environment where the sensor wire 1 is installed, the temperature in that environment, and changes in the substances present. Alternatively, the sensor wire 1 can be incorporated into a wire harness along with other wires, and the sensor device 2 can be used as a component for detecting mechanical deformation and environmental changes applied to the entire wire harness. Next, the method of using the sensor device 2 as a component of this wire harness will be described.

[0065] (3) Wire harness

[0066] like Figure 2 As shown in Figure (2B), the wiring harness 3 of one embodiment of this disclosure includes the aforementioned sensor device 2 and target wire 31. In the illustrated embodiment, the sensor device 2 is a sensor device equipped with a spiral-type sensor wire 1A. The target wire 31 is a wire that serves as the object for monitoring mechanical deformation and environmental changes through the sensor device 2, and is composed of at least one wire. In the illustrated embodiment, the target wire 31 includes only one wire. If the target wire 31 includes multiple wires, these multiple wires can be bundled together by aligning their length directions with each other.

[0067] In the wiring harness 3, the sensor wire 1 constituting the sensor device 2 is arranged along the length direction of the target wire 31 in at least a portion of the area. When the sensor wire 1 has a planar structure, such as the spiral-type sensor wire 1A shown in the figure, it is sufficient to arrange the sensor wire 1 in contact with or close to the target wire 31 at a portion of the long axis direction, for example, at a location susceptible to mechanical deformation or environmental changes. When the sensor wire 1 has a linear structure, such as the coil-type sensor wire 1B, it is sufficient to arrange the axis of the sensor wire 1 aligned with the length direction axis of the target wire 31. In this case, it is possible to arrange the sensor wire 1 and the target wire 31 in a manner that allows the target wire 31 to pass through the hollow portion 111 of the double-wire coil wire 11B constituting the coil-type sensor wire 1B, or to arrange the sensor wire 1 and the target wire 31 together in a manner that prevents them from being separated. Preferably, the target wire 31 and the sensor wire 1 are integrated using an outer casing material, tape, or the like.

[0068] As described above, in sensor device 2, when mechanical deformation or environmental changes are applied to sensor wire 1, these changes can be detected by the change in the response signal. In wire harness 3, sensor wire 1 and target wire 31 are configured together, and as an assembly of sensor wire 1 and target wire 31, they are subject to mechanical deformation and environmental changes. Therefore, in sensor device 2, when mechanical deformation or environmental changes are detected on sensor wire 1, it means that the same mechanical deformation or environmental changes have also been applied to target wire 31. Thus, when changes such as mechanical deformation or environmental changes occur that affect the characteristics and function of target wire 31, these changes can be detected using sensor wire 1. Using the detection results, for example, the impact of these changes on the characteristics and function of target wire 31 can be considered when using target wire 31. Furthermore, measures such as replacing target wire 31 can be taken before the effects of mechanical deformation and environmental changes accumulate and cause irreversible damage or deterioration to target wire 31.

[0069] Alternatively, in the wiring harness 3, in addition to using the sensor device 2 as a unit for detecting unwanted changes in the target wire 31 and taking countermeasures, as described above, the sensor device 2 can also be used as an input unit for external indications and information. For example, in the wiring harness 3 connected to the device, a sensor wire 1 can be placed at the end of the target wire 31 or in the middle of its path. By applying mechanical deformation or environmental changes to the sensor wire 1 from the outside, the indications and information required for the operation of the device can be input. Moreover, the system can be constructed such that the monitoring unit 21 reads the input indications and information in the form of changes in response signals and inputs them into the device. As an input method for indicating and providing information about mechanical deformation or environmental changes that can be applied to the sensor wire 1, it is possible to touch or press the sensor wire 1 with a finger.

[0070] <Monitoring based on changes in sensor wiring>

[0071] Next, the mechanism for monitoring changes such as mechanical deformation and environmental changes in the sensor wire 1, along with the structure of the sensor wire 1 suitable for implementing this mechanism, will be described. First, the case of mechanical deformation applied to the sensor wire 1 will be explained in detail. Next, the case of environmental changes, i.e., temperature changes or changes in the substances it comes into contact with, applied to the sensor wire 1 will be described. In the description of the case of environmental changes, matters common to the case of mechanical changes will be appropriately omitted. The following explanation will use the case of measuring characteristic impedance as the response signal as an example.

[0072] (1) The case of applying mechanical deformation

[0073] As a representative example of mechanical deformation, we will explain the case where applying a mechanical load to the sensor wire 1 causes mechanical deformation in the direction that increases the distance between the insulated wires 12a and 12b constituting the sensor wire 1. In the spiral-type sensor wire 1A, examples of mechanical deformation in the direction that increases the distance between the insulated wires 12a and 12b include deformation from an initial planar structure to a conical three-dimensional structure by lifting the central portion, and deformation of the spiral shape in a direction that expands inward. Additionally, examples include extending the coil-type sensor wire 1B along its central axis.

[0074] exist Figure 3 In Figure (3A), a cross-section of the wire assembly 11 cut along a reference line B is schematically shown regarding the sensor wire 1 in its undeformed initial state. In the figure, the first insulated wire 12a and the second insulated wire 12b constituting the wire assembly 11 are arranged alternately. Furthermore, by inputting a differential signal as a check signal to the wire assembly 11, the polarities of the pair of insulated wires 12a and 12b are different, and in the cross-sectional view, the insulated wires 12a and 12b with opposite polarities are arranged alternately (polarity is indicated by + and - symbols in the figure). The wire assembly 11 generates an electric field in the space surrounding the wire assembly 11 by the input check signal, as shown by the dashed and dotted lines in the figure, connecting adjacent insulated wires 12a and 12b to generate electric field lines. In the figure, the dashed and dotted lines represent electric field lines pointing in opposite directions. The density of the electric field lines corresponds to the electric field strength. The magnitude of the characteristic impedance, measured as a response signal, reflects the state of the electric field generated by the wire assembly 11. It should be noted that the display style of the figure is... Figure 3 Figure (3B) ~ Figure 6 The same applies in Figure (6B).

[0075] When from Figure 3 When the state shown in Figure (3A) causes the wire assembly 11 to deform in the direction that increases the distance between the insulated wires 12a and 12b, as shown in Figure (3A), Figure 3 As shown in Figure (3B), in the wire assembly 11, adjacent insulated wires 12a and 12b are separated from each other along the reference line B. Therefore, the density of electric field lines decreases in the space surrounding the wire assembly 11. That is, the electric field strength weakens. The increase in distance between adjacent insulated wires 12a and 12b occurs in two ways: between groups of two adjacent insulated wires 12a and 12b whose longitudinal axes are aligned; and between two adjacent insulated wires 12a and 12b that have become adjacent through bending in the wire assembly 11, which is formed into a predetermined shape by bending such groups.

[0076] In the wire assembly 11, adjacent insulated wires 12a and 12b have opposite polarities, thus acting as a capacitor. The characteristics of this capacitor affect the characteristic impedance between the pair of insulated wires 12a and 12b. The capacitor characteristics vary depending on the distance between the electrodes. In the sensor wire 1 of this embodiment, if mechanical deformation is applied to the wire assembly 11, the distance between adjacent insulated wires 12a and 12b with opposite polarities widens, the electric field strength in the space near the wire assembly 11 weakens, and the characteristic impedance measured as a response signal in the sensor wire 1 increases. The greater the deformation of the wire assembly 11, the greater the increase in characteristic impedance.

[0077] Using this, if a mechanical deformation is applied to the sensor wire 1 itself or to the wiring harness 3 containing the sensor wire 1 in a direction that increases the distance between the insulated wires 12a and 12b, it can be detected by the sensor wire 1. For example, if the characteristic impedance of the response signal obtained as an input inspection signal to the sensor wire 1 in the wiring harness 3 changes in a direction that exceeds a predetermined reference, it can be determined that a mechanical load has been applied to the sensor wire 1 and the target wire 31 in a direction that increases the distance between the insulated wires 12a and 12b constituting the wire assembly 11. The reference value can be determined as the amount of change in the characteristic impedance of the sensor wire 1 corresponding to the upper limit of the allowable deformation in the target wire 31. If an excessive mechanical load is applied to the wire, it can lead to abnormalities such as wire breakage. Therefore, by detecting the load in advance before a real abnormality caused by the accumulation of the load effect occurs in the target wire 31, countermeasures can be taken as early as possible.

[0078] In the sensor wire 1 of this embodiment, the pair of insulated wires 12a and 12b are not arranged so that their length axes are aligned and extended straight. Instead, they are arranged as a wire assembly 11 with bends forming a spiral or helical shape. This allows for sensitive detection of mechanical deformation as a change in the response signal. One reason for this is that the characteristic impedance change caused by the change in distance between the insulated wires 12a and 12b, which have opposite polarities as described above, can be utilized by the deformation of the wire assembly 11, i.e., the change in the overall shape of the wire assembly 11. If the pair of insulated wires 12a and 12b are arranged so that their length axes are extended straight, such a change in characteristic impedance based on the change in distance between the insulated wires 12a and 12b is less likely to occur. Furthermore, as another reason, by forming the wire assembly 11 with bending, the actual length (length of the insulated wires 12a and 12b along their long side) of the wire assembly 11 becomes longer, and the total change in characteristic impedance over the entire region of the wire assembly 11 increases. Moreover, the deformation of the wire assembly 11 can occur reversibly, so even if the application of mechanical loads to the wire harness 3 occurs repeatedly and intermittently, the application of these loads can be detected each time a load is applied. This differs from detection components that detect the application of external loads by causing irreversible damage, as disclosed in Patent Document 1, such as conductive strips and laminated strips.

[0079] In the wire assembly 11 constituting the sensor wire 1, a pair of insulated wires 12a and 12b are bent and shaped, and can potentially function as electromagnets to generate a magnetic field by inputting a check signal as an alternating current. In particular, in the coil-type sensor wire 1B, the insulated wires 12a and 12b are helical, thus easily functioning as electromagnets. However, since the pair of insulated wires 12a and 12b are shaped with their longitudinal axes aligned to form the prescribed shape of the wire assembly 11, and the check signal, composed of a differential signal, imparts opposite polarities to the pair of insulated wires 12a and 12b, the magnetic fields generated by the pair of insulated wires 12a and 12b respectively are opposite and cancel each other out. Therefore, the wire assembly 11 as a whole does not substantially generate a magnetic field. From the viewpoint of effectively suppressing the generation of a magnetic field, the support member 13 is preferably made of a non-magnetic material. It should be noted that for structures formed by bending a single insulated wire into a spiral or similar shape, when an AC signal is input, not only may a magnetic field be generated, but even under mechanical deformation or environmental changes, the characteristic impedance of the response signal will hardly change, thus failing to function as a sensor wire.

[0080] The above explains that when the sensor wire 1 is deformed in the direction that increases the distance between the insulated wires 12a and 12b, the deformation can be detected by the change in characteristic impedance obtained as a response signal when an inspection signal composed of a differential signal is input. However, even when other types of mechanical deformation are applied to the sensor wire 1, the mechanical deformation can still be detected by the change in the response signal through the change in the electric field caused by the change in the distance between the alternating insulated wires 12a and 12b in the overall shape of the wire assembly 11. For example, when the sensor wire 1 is deformed from a state where there is a certain distance between the insulated wires 12a and 12b to a direction that decreases the distance, the adjacent insulated wires 12a and 12b along the reference line B in the wire assembly 11 approach each other, thereby reducing the characteristic impedance obtained as a response signal when an inspection signal is input. The greater the deformation, the greater the reduction in the response signal.

[0081] Furthermore, when the sensor wire 1 is bent—that is, when the plane formed by the spiral-type sensor wire 1A is bent and deformed, or when the central axis of the coil-type sensor wire 1B is bent from a straight state to an arc shape—the characteristic impedance obtained as a response signal also changes. This is because, in some parts constituting the bent shape (e.g., the outer side of the bent shape in the coil-type sensor wire 1B), the sensor wire 1 elongates, and the distance between adjacent insulated wires 12a and 12b increases; while in other parts constituting the bent shape (e.g., the inner side of the bent shape in the coil-type sensor wire 1B), the sensor wire 1 is compressed, and the distance between adjacent insulated wires 12a and 12b decreases. The direction of change in the response signal also depends on the specific bent shape. When a pair of insulated wires 12a and 12b are relatively closely packed in the wire assembly 11, the effect of deformation in the direction of increasing distance between adjacent insulated wires 12a and 12b is stronger, and the change in characteristic impedance as a response signal occurs in the increasing direction due to bending. The greater the bending amount, the greater the change in the response signal.

[0082] From the viewpoint of sensitively detecting changes in the response signal by means of the mechanical deformation of the sensor wire 1, it is preferable that the insulation sheath 122 of the insulated wires 12a and 12b constituting the wire assembly 11 is thin. This is because, in the assembled shape of the wire assembly 11, when the distance between the conductors 121 constituting adjacent insulated wires 12a and 12b is short, the change in the electric field caused by the mechanical deformation of the wire assembly 11 becomes larger, resulting in a large change in the characteristic impedance. As will be described later, when using the sensor wire 1 to detect changes in the environment, the thinner the insulation sheath 122, the more easily changes in the surrounding environment are reflected as changes in the electric field formed by the conductors 121. The insulation sheath 122 should be as thin as possible within the range that ensures the insulation of the conductors 121, and enameled wire is most preferably used as the insulated wires 12a and 12b.

[0083] Furthermore, in the wire assembly 11, it is preferable that a pair of insulated wires 12a and 12b, which are bent and assembled into a predetermined assembly shape with their longitudinal axes aligned, are tightly assembled in a manner that reduces the gaps between adjacent portions formed by bending, such as at the circumference of the spiral shape and between the turns of the helical shape. Thus, in the wire assembly 11, the distance between the insulated wires 12a and 12b, which are grouped with their longitudinal axes aligned (for example, in…) Figure 3 In Figure (3A), the distance between the nth and (n+1)th insulated wires from the left (n is a positive odd number) and the distance between adjacent insulated wires 12a and 12b that are bent (in... Figure 3 In Figure (3A), the difference in distance between the (n+1)th and (n+2)th insulated wires from the left decreases, and the characteristic impedance changes caused by mechanical deformation and environmental changes occur with high uniformity throughout the entire area of ​​the wire assembly 11. Furthermore, by arranging the insulated wires 12a and 12b in the wire assembly 11 at a high density, the amount of characteristic impedance change caused by mechanical deformation and environmental changes increases. Preferably, the wire assembly 11 is formed by bending a pair of insulated wires 12a and 12b arranged close together without gaps in adjacent areas, except for unavoidable gaps.

[0084] In the sensor wire 1, from the viewpoint of reflecting changes in the response signal as a large proportion of mechanical deformation, it is preferable not to provide a support member 13 for the sensor wire 1, and to keep the wire assembly 11 in a deformable state. However, from the viewpoint of easily enabling the sensor wire 1 to stand upright, and from the viewpoint of not detecting minor deformations such as deformations caused by normal minor vibrations through the sensor wire 1, it is preferable to support the wire assembly 11 with a support member 13. As the support member 13, it is preferable to use a support member that can deform along with the wire assembly 11 and the object wire 31 being monitored without excessively hindering their mechanical deformation. That is, as the support member 13, a member with flexibility (flexibility, extensibility) that can deform with the deformation of the wire assembly 11 is acceptable.

[0085] As a mechanically easily deformable support member 13, a relatively thin plate material can be used for the spiral-type sensor wire 1A. In particular, the plate material can be made of resin material. On the other hand, for the coil-type sensor wire 1B, a core material made of a hollow cylindrical body can be used. Hollow cylindrical bodies are more easily deformed by external forces than solid bodies. In particular, hollow cylindrical bodies can be made of resin material. When it is desirable to suppress changes in the response signal caused by temperature changes in order to dominate the detection of mechanical deformation using the sensor wire 1, the support member 13 made of a hollow cylindrical body can be designed with both ends open along the central axis of the double-wire coil wire 11B. This is to suppress the effect of expansion / contraction of air sealed in the hollow part. It should be noted that when it is desirable to suppress changes in the response signal caused by mechanical deformation in order to dominate the detection of changes in substances in the environment, etc., the support member 13 can be made into a shape that is difficult to deform, such as a thick plate material in the spiral-type sensor wire 1A and a solid rod in the coil-type sensor wire 1B.

[0086] As a sensor wire 1 for detecting mechanical deformation, the wire assembly 11 can be any shape, but compared to a planar structure, such as the spiral-type sensor wire 1A, a linear structure, such as the coil-type sensor wire 1B, can more sensitively detect mechanical deformation. This is because when an external force is applied, the linear sensor wire 1 is prone to large mechanical deformations along the axis of the linear structure, such as spiral expansion or contraction, resulting in a large change in the response signal. On the other hand, when using a planar sensor wire 1, such as the spiral-type sensor wire 1A, the deformation can be detected regardless of which part of the surface formed by the wire assembly 11 is subjected to mechanical deformation. Therefore, when it is necessary to detect mechanical deformation over an area of ​​a certain size, it is preferable to use a planar sensor wire 1.

[0087] (2) Changes in the substances that come into contact

[0088] As for changes in the environment applied to the sensor wire 1, examples include temperature changes and changes in the material in contact with the wire assembly 11. First, the case where the material in contact with the wire assembly 11 changes will be explained. There are two cases for changes in the material in contact with the wire assembly 11: one is a change in the type of material in contact with the wire assembly 11, that is, a material different from the initially contacted material comes into contact with the wire assembly 11; and the other is a change in the state of the material in contact with the wire assembly 11. However, in either case, the response signal changes because the dielectric constant of the material surrounding the wire assembly 11 changes, through the same mechanism.

[0089] First, let's take the case of liquid contacting the wire assembly 11 as an example. Figure 4 Figures (4A) and (4B) schematically show a cross section of the wire assembly 11 cut along the reference line B in relation to the contact between the liquid and the wire assembly 11. Figure 4 Figure (4A) shows the wire assembly 11 before contact with the liquid, and Figure 3 The wire assembly shown in Figure (3A) is the same. Figure 4 Figure (4B) shows the state of the liquid L after it comes into contact with the wire assembly 11.

[0090] The electric field generated when an inspection signal is input to the wire assembly 11 depends on the dielectric constant of the surrounding material; the higher the dielectric constant, the stronger the electric field. That is, the density of electric field lines between adjacent insulated wires 12a and 12b increases. Figure 4 In Figure (4A), before contact with the liquid L, the wire assembly 11 is surrounded by air and in contact with the air. The relative permittivity of air is approximately 1, therefore the density of the electric field lines is low. Conversely, when the liquid L contacts the wire assembly 11, as... Figure 4 As shown in Figure (4B), the liquid L covers the surface of the wire assembly 11 and also enters the space between adjacent insulated wires 12a and 12b in the assembly shape of the wire assembly 11. Typical liquid substances have a higher dielectric constant than air. Therefore, through the contact of the liquid L, the electric field strength formed by the wire assembly 11 increases, such as... Figure 4 As shown in Figure (4B), the density of electric field lines formed between adjacent insulated wires 12a and 12b increases. As a result, the characteristic impedance measured as a response signal in sensor wire 1 decreases. The wider the area in contact with the liquid L in the wire assembly 11, the greater the reduction in characteristic impedance.

[0091] Using this information, when liquid L comes into contact with sensor wire 1 itself or the wiring harness 3 containing sensor wire 1, it can be detected through sensor wire 1. For example, in wiring harness 3, if the response signal obtained after inputting a check signal to sensor wire 1 changes in a decreasing direction exceeding a predetermined reference, it can be determined that liquid L has come into contact with sensor wire 1 and target wire 31. The reference value can be determined as the change in characteristic impedance of sensor wire 1 corresponding to the upper limit of the allowable contact amount. In wires, when liquids such as water and oil come into contact, the conductivity of the liquid, if present, and the deterioration of the wire components caused by the liquid, may affect the performance of the wire, such as reducing insulation. Especially in automotive wiring, water from the external environment, engine oil, and other oils from inside the car may infiltrate the parts in contact with the wires due to poor sealing, making it important to detect this intrusion as early as possible. In the above-described method of detecting the mechanical deformation in the direction of separation of the distance between the insulated wires 12a and 12b, it is preferable to form the insulated wires 12a and 12b into a predetermined assembly shape by bending them in adjacent parts without gaps in the wire assembly 11. However, in the case of detecting the contact of liquid L described here, from the viewpoint of increasing the change in the response signal caused by the liquid L entering between the insulated wires 12a and 12b constituting the wire assembly 11, it is preferable to provide a certain degree of gap between the adjacent insulated wires 12a and 12b formed by bending in the wire assembly 11, so that the liquid L can easily enter.

[0092] In the case where the material in contact with the wire assembly 11 is liquid, even in the case where it is solid, changes in the material in contact with the wire assembly 11 can be detected by the change in the characteristic impedance, which serves as a response signal. In the case of a solid material, similar to the case of a liquid material described above, the response signal of the sensor wire 1 changes via the change in the dielectric constant of the material surrounding the wire assembly 11. However, in the case of a liquid material, as... Figure 4 As shown in Figure (4B), when in contact with the wire assembly 11, it enters the gap between the insulated wires 12a and 12b constituting the wire assembly 11. However, in the case of a solid material, it is not possible to enter the gap between the insulated wires 12a and 12b in this way, and it only contacts the surface of the wire assembly 11 (see Figure 4B). Figure 5 (See Figure (5A)). Therefore, when a material with the same dielectric constant comes into contact with the wire assembly 11, if the material is solid, the change in the response signal is less likely to increase compared to the case where it is liquid. The change in the response signal caused by the contact of a solid material with the wire assembly 11 can be appropriately used, for example, for finger-based touch indication and information input.

[0093] In the above description, the change in the substance in contact with the wire assembly 11 varies, ranging from air to other liquid or solid substances. However, the case where the same substance remains in contact with the wire assembly 11 but its state changes is also described. Examples of changes in the state of matter include phase transitions and chemical changes. After a phase transition or chemical change, the dielectric constant of the substance in contact with the wire assembly 11 changes, and the distribution of the substance surrounding the wire assembly 11 changes. This causes a change in the state of the electric field formed by the wire assembly 11, resulting in a change in the response signal obtained in the sensor wire 1. Based on this change in the response signal, the change in the state of the substance in contact with the wire assembly 11 can be detected.

[0094] As an example of a phase transition occurring during a change in the state of the material in contact with the wire assembly 11 (the contact material), the case where the contact material melts and changes from a solid to a liquid can be illustrated. In many materials, the dielectric constant differs between solid and liquid states; therefore, due to the phase transition from solid to liquid, the characteristic impedance obtained as a response signal in the sensor wire 1 changes. Furthermore, the contact material in contact with the wire assembly 11 gains fluidity through melting, thereby... Figure 5 As shown in Figures (5A) and (5B), the spatial distribution of the contact material changes, which in turn imparts a change to the characteristic impedance.

[0095] Figure 5 Figure (5A) shows the state of the solid contact material C before melting, as a cross-sectional view of the wire assembly 11. Figure 5 Figure (5B) shows the state of the contact material C after melting, as a cross-sectional view of the wire assembly 11. Figure 5 As shown in Figure (5A), in its pre-melting state, the contact material C is only in contact with the wire assembly 11 on the surface of the solid, but gains fluidity through melting, thus... Figure 5 As shown in Figure (5B), the material enters the gap between the insulated wires 12a and 12b constituting the wire assembly 11. Thus, by distributing the contact material C near the insulated wires 12a and 12b constituting the wire assembly 11, the dielectric constant of the region near the insulated wires 12a and 12b increases. As a result, the electric field strength near the wire assembly 11 increases, and the density of electric field lines also increases. Consequently, the characteristic impedance obtained as a response signal decreases. This mechanism is based on the above... Figure 4 The mechanisms that illustrate the contact of liquid L in Figures (4A) and (4B) are the same.

[0096] When the contact material C is heated and melts, if it is cooled, the contact material C returns to a solid state, but maintains the spatial distribution of the molten contact material C, i.e., as shown in the image. Figure 5 As shown in Figure (5B), it enters the gap between the insulated wires 12a and 12b that constitute the wire assembly 11, and returns to a solid state. That is, with Figure 5 Compared to the state before melting, as shown in Figure (5A), even if the dielectric constant of the contact material C is the same, by distributing the contact material C near the insulated wires 12a and 12b that constitute the wire assembly 11, the dielectric constant in the region near the insulated wires 12a and 12b increases, and the characteristic impedance obtained as a response signal decreases.

[0097] Next, as an example of a chemical change in the state of the material in contact with the wire assembly 11, the following can be cited: the contact material C in contact with the wire assembly 11 undergoes a chemical reaction, decomposes, or deteriorates with other substances such as components in the atmosphere in which the contact material C is placed, thereby changing the dielectric constant of the contact material C. Figure 6 Figures (6A) and (6B) show cross-sectional views of the contact substance C undergoing a chemical change.

[0098] Figure 6 Figure (6A) shows the state of the contact substance C before a chemical change occurs. Figure 6 Figure (6B) shows the state after a chemical change occurs in the contacting substance C. Here, as a chemical change, we imagine a reaction in which the dielectric constant of the contacting substance C increases. For example... Figure 6 As shown in Figure (6B), when the dielectric constant of the contact material C increases due to a chemical change, the electric field strength formed by the wire assembly 11 increases, and the density of the electric field lines also increases. Consequently, the characteristic impedance obtained as a response signal in the sensor wire 1 decreases. Conversely, when the dielectric constant of the contact material C decreases due to a chemical change, the characteristic impedance increases.

[0099] Thus, by detecting changes in the response signal obtained in the sensor wire 1, chemical changes in the contact material C can be detected. This detection of chemical changes is applicable to cases where the dielectric constant of the contact material C changes due to chemical changes, and to cases where conductivity, a physical property correlated with the dielectric constant, changes. By detecting phase transitions and chemical changes in the contact material C, changes in the sensor wire 1 itself and the environment in which the wire harness 3 containing the sensor wire 1 is placed can be detected.

[0100] The contact material C, which contacts the wire assembly 11 of the sensor wire 1, is envisioned as a material existing outside the sensor wire 1 in the environment where the sensor wire 1 is placed, but it can also be a material inside the sensor wire 1. That is, the sensor wire 1 can be constructed by pre-assembling the contact material C. As the contact material C, it is disposed in contact with the wire assembly 11 by a material whose dielectric constant changes sensitively according to changes in the environment in which the sensor wire 1 is placed. Thus, when a change in the environment occurs, the change in the dielectric constant of the contact material C can be used to detect the change in the response signal of the sensor wire 1 with high sensitivity. The dielectric element described above in relation to the general structure of the sensor wire 1 corresponds to the contact material C of the sensor wire 1 that is intentionally incorporated in this way. As described above, the dielectric element is a material that causes a change in the dielectric constant in the region surrounding the wire assembly 11 due to changes in the environment, and the dielectric element is disposed in contact with the wire assembly 11. As phenomena that cause a change in the dielectric constant in the dielectric element, phase transitions and chemical changes of the dielectric element can be cited as examples.

[0101] As an example of using a dielectric material, the use of a water-absorbing polymer can be cited. A water-absorbing polymer is a substance that undergoes a phase transition from a solid state to a gel state by absorbing water. In the sensor wire 1, a dry water-absorbing polymer is filled into the internal space of the wire assembly 11 (e.g., the hollow portion 111 of the bifilar coil wire 11B), shaped into a sheet or tube, and disposed on the surface of the wire assembly 11, thus being in contact with the wire assembly 11. In this state, if water is introduced into the space where the sensor wire 1 is placed and comes into contact with the water-absorbing polymer, the water-absorbing polymer absorbs the water and gels. Compared to the water-absorbing polymer before absorbing water, the water-absorbing polymer that has absorbed water generally has a high dielectric constant. Furthermore, along with gelation, the water-absorbing polymer swells and comes into close contact with the insulated wires 12a and 12b constituting the wire assembly 11. As a result, the characteristic impedance obtained as a response signal in the sensor wire 1 increases. In this way, by using a water-absorbing polymer as a medium, water can be sensitively detected when it is introduced into the space containing the sensor wire 1 or the wire harness 3 containing the sensor wire 1.

[0102] Another example of using a dielectric material is the use of a functional material (gas detection material) that undergoes a chemical reaction upon contact with specific gas molecules. In the sensor wire 1, this gas detection material is filled into the space within the wire assembly 11, shaped into a sheet or tube, and disposed on the surface of the wire assembly 11, bringing it into contact with the wire assembly 11. In this state, when gas molecules that cause a chemical reaction with the gas detection material are introduced into the space where the sensor wire 1 is placed, the gas detection material contacts the gas molecules, resulting in a chemical reaction. When the dielectric constant and conductivity of the gas detection material change due to the chemical reaction, the characteristic impedance obtained as a response signal in the sensor wire 1 changes. By detecting this change, it is possible to detect that the gas molecules have been introduced into the space where the sensor wire 1 is located. For example, in a hydrogen vehicle, if a sensor wire 1 equipped with a gas detection material that selectively detects hydrogen as a dielectric material is placed at a location where hydrogen leakage may occur, detection can be performed as early as possible in the event of a hydrogen leak.

[0103] As a sensor wire 1 for detecting changes in the contacting substance, any wire assembly 11 with any bundle shape can be used. However, if a sensor wire 1 with a planar structure, such as a spiral-type sensor wire 1A, is used, the change in the contacting substance can be detected regardless of where the change occurs on the surface formed by the wire assembly 11. Therefore, when it is necessary to detect changes in the contacting substance over an area extending to a certain extent, it is preferable to use a sensor wire 1 with a planar structure. On the other hand, when it is necessary to detect changes in the contacting substance over an area extending to a certain length, a sensor wire 1 with a linear structure, such as a coil-type sensor wire 1B, can be used.

[0104] (3) Applying temperature changes

[0105] Next, the case of temperature change in the environment applied to sensor wire 1 will be explained. Temperature changes in sensor wire 1 can be detected directly by means of the change in the dielectric constant of the surrounding material caused by the temperature change, or by means of the mechanical deformation of the wire assembly 11, as described above, or by means of the change in the material in contact with the wire assembly 11. In most cases, the change in the dielectric constant of the material caused by temperature changes without phase transition is small. In the case of direct detection based on the change in the dielectric constant of the surrounding material, the change in the response signal is small. However, by utilizing the mechanical deformation of the wire assembly 11 and the change in the material in contact with the wire assembly 11, the change in the response signal can be increased.

[0106] An example of detecting temperature changes through the mechanical deformation of the wire assembly 11 can be given as follows: In the sensor wire 1 supported by the support member 13, when the sensor wire 1 is heated, the support member 13 expands, and deformations occur in the wire assembly 11, such as the elongation of the bi-coil wire 11B and the expansion of the spiral shape of the bi-spiral wire 11A. Thus, when deformation occurs accompanying a change in the distance between adjacent insulated wires 12a and 12b, the characteristic impedance, as a response signal, changes due to a change in the state of the electric field, through the same mechanism described above for the deformation of the wire assembly 11 caused by mechanical load. The greater the temperature rise, the greater the expansion of the support member 13, and the greater the change in the response signal.

[0107] To ensure that temperature changes are sensitively reflected as changes in the response signal, the support member 13 is preferably one that expands / contracts significantly due to temperature changes. Examples of such a support member 13 include those with an internal space filled with gas. For instance, a core material configured as a hollow cylindrical body closed at both ends could be used as the support member 13 for a coil-type sensor wire 1B. When such a support member 13 is heated, the gas inside expands, and as the gas expands, the outer wall of the support member 13 is also pushed open and expands. By utilizing the gas expansion in this way, the deformation of the support member 13 increases with temperature rise, and consequently, the change in the response signal also increases. The gas filled in the support member 13 can be air or a gas other than air. Furthermore, the pressure of the filled gas can be atmospheric pressure, but if the gas is filled at a pressure higher than atmospheric pressure, the expansion amount upon temperature rise can be increased.

[0108] As an example of detecting temperature changes by means of changes in the material in contact with the wire assembly 11, the dielectric material constituting the sensor wire 1 can be a material containing a change in the dielectric constant of the region surrounding the wire assembly 11 caused by temperature changes. Even if the gas in the space where the wire assembly 11 is placed experiences a temperature change, the change in dielectric constant is only minimal. However, through the state change and chemical change of the dielectric material caused by temperature, a large change in dielectric constant is brought about around the wire assembly 11, which can be detected as a large change in the response signal.

[0109] As an example of using a dielectric element to detect temperature changes, one method is to place an adhesive-coated material as the dielectric element on the outside of the wire assembly 11. The adhesive-coated material refers to a material on the surface of a sheet-like or tubular substrate having a layer of adhesive made of a material (thermoplastic material) that softens or melts, preferably melts, upon heating. For sensor wires 1 with a planar structure, such as spiral-type sensor wires 1A, a material with an adhesive layer on one side of the sheet-like substrate can be used as the dielectric element. It is sufficient to ensure that the surface of this dielectric element with the adhesive layer is in contact with the surface of the wire assembly 11. On the other hand, for sensor wires 1 with a linear structure, such as coil-type sensor wires 1B, a material with an adhesive layer on the inner circumferential surface of a tubular substrate can be used as the dielectric element. This dielectric element can be placed over the outer circumference of the wire assembly 11. As a tubular material with an adhesive layer on its inner circumferential surface, a heat-shrinkable tube can be used. Heat-shrinkable tubes with an adhesive layer are commonly used as components for insulation and protection of electrical components.

[0110] In the sensor wire 1 equipped with a dielectric component having an adhesive layer, when the temperature rises due to an increase in the ambient temperature and rises above a temperature above which the adhesive can flow by softening or melting, such as Figure 5 Figure (5A) to Figure 5 As shown in Figure (5B), the adhesive flows and enters the gap between the insulated wires 12a and 12b of the wire assembly 11. Furthermore, when the dielectric element is made of heat-shrink tubing, when the temperature rises to the temperature at which the heat-shrink tubing contracts, the heat-shrink tubing contracts, thereby subjecting the adhesive to a pressing force towards the wire assembly 11, promoting the penetration of the adhesive into the space between the insulated wires 12a and 12b. Then, even if the ambient temperature drops, the adhesive... Figure 5 As shown in Figure (5B), the adhesive is cured while maintaining the gap between the insulated wires 12a and 12b that enter the wire assembly 11. In this way, the adhesive enters the gap between the insulated wires 12a and 12b that constitute the wire assembly 11, thereby reducing the characteristic impedance obtained as a response signal in the sensor wire 1.

[0111] In electrical wiring used in automobiles and other applications, temperature changes can affect the wire's function, including altering its transmission characteristics. Furthermore, large or repeated temperature changes can cause irreversible damage and deterioration to the wire's components, such as the insulation, and surrounding structures. By using the sensor wire 1 to detect temperature changes in both the separately configured sensor wire 1 and the wiring harness 3 containing the target wire 31 and the sensor wire 1, countermeasures against these phenomena can be implemented.

[0112] (4) Various methods of monitoring based on sensor wires

[0113] As explained above, by using the sensor wire 1, environmental changes, such as mechanical deformation, temperature changes, and changes in the contacting material, can be detected based on the change in the response signal obtained when an inspection signal composed of a differential signal is input. For example, when the response signal changes beyond a reference, it can be determined that any one of the following phenomena has occurred: mechanical deformation, temperature change, or change in the contacting material. Based on this, when the sensor wire 1 is used to monitor undesirable phenomena, the monitoring unit 21 of the sensor device 2 can be configured to appropriately notify personnel such as administrators of the system containing the sensor wire 1 by issuing alarms. On the other hand, when the sensor wire 1 is used to input external instructions or information, the system can be constructed such that when the response signal changes beyond a reference, the device connected to the sensor wire 1 determines that the prescribed instructions or information required for operation has been input, and performs the operation corresponding to those instructions or information. In either case, the reference value of the response signal is determined corresponding to the lower limit of the amount of change that should be considered a change.

[0114] Regarding which specific change phenomenon is sensitively detected, as explained above for each method, this can be determined by selecting the assembly shape of the insulated wires 12a and 12b in the wire assembly 11, the presence or absence of the support member 13 and the dielectric member, their structure, and the materials used in their composition. Generally, linear sensor wires 1, primarily coil-type sensor wires 1B, are particularly suitable for detecting mechanical deformation and temperature changes, while planar sensor wires 1, primarily spiral-type sensor wires 1A, are particularly suitable for detecting changes in the contacted substance.

[0115] In sensor device 2, when a check signal is input and a response signal is obtained, the strength of the signal at a specific frequency that is the response signal is monitored. If a predetermined change occurs in the strength of the response signal obtained at that frequency, it is determined that a change has occurred in sensor wire 1. Furthermore, the greater the change in the response signal, the greater the degree of change is considered. Alternatively, a check signal covering a certain frequency range can be input, and the presence and degree of a change can be determined based on the change in the response signal within that frequency range. Furthermore, if the response signal is measured using a time-domain method or a frequency-domain method, by establishing a correspondence between the information of the area and position where the change occurred in the response signal, the location of changes such as local deformation or local contact with external materials can be determined in sensor wire 1. In the case of the time-domain method, the time axis can be transformed into the position on sensor wire 1 based on the propagation speed of the check signal. On the other hand, in the case of the frequency-domain method, by performing an inverse Fourier transform on the response signal obtained with respect to the frequency axis, the frequency information can be transformed into the position on sensor wire 1. Preferably, a time-domain reflectometry method or a frequency-domain reflectometry method can be used. In the sensor device 2, response signals can be acquired continuously to continuously monitor whether changes occur in the sensor wire 1, or response signals can be acquired intermittently so that when changes occur in the sensor wire 1, they can be detected with less delay.

[0116] In the wiring harness 3, the location where sensor wires 1 are configured and changes are monitored can be the entire area along the length of the target wire 31, or it can be a specific area, such as a location prone to mechanical deformation or other changes. Furthermore, the wiring harness 3 can have only one sensor wire 1, or multiple sensor wires 1 can be configured along the length of the target wire 31. For example, if multiple locations along the length of the target wire 31 where mechanical deformation or other changes are prone to occur are discontinuous, sensor wires 1 can be configured at each of these locations. When multiple sensor wires 1 are configured, they can be connected in series. In this case, the input of the inspection signal and the acquisition of the response signal can be performed on the entire group of multiple series-connected sensor wires 1. Furthermore, based on the behavior of the acquired response signal, it is possible to detect which sensor wire 1 has experienced a change. For example, if a response signal is acquired across a certain frequency range, the resulting spectral shape changes depending on which sensor wire 1 has experienced a change; therefore, it is possible to determine which sensor wire 1 experienced a change based on the spectral shape. Alternatively, as described above, if time-domain or frequency-domain methods are applied, the sensor wire 1 that has undergone a change can be determined with high precision. Multiple sensor wires 1 connected in series can all be configured to detect mechanical elongation, etc., can all be of the same type, or multiple sensor wires 1 with structures suitable for detecting different changes can be connected. Alternatively, multiple sensor wires 1 with structures suitable for detecting different changes can be configured in parallel on a single wire harness 3, and the response signal of each sensor wire 1 can be monitored independently. When multiple sensor wires 1 are configured in series or parallel, these sensor wires 1 can be linear, such as coil-type sensor wire 1B, planar, such as spiral-type sensor wire 1A, or a combination of both. Furthermore, as sensor wires 1, only sensor wires monitoring unwanted changes can be used, only sensor wires for inputting indications or information can be used, or a combination of both can be used.

[0117] Example

[0118] The following are examples. It should be noted that the present invention is not limited to these examples. Here, it was confirmed whether various changes could be detected via sensor wires.

[0119] [1] Detection of mechanical deformation

[0120] First, the mechanical deformation of the sensor wire was verified using a coil-type sensor wire.

[0121] (Experimental Methods)

[0122] First, the sensor wire, which will become the sample, is fabricated with... Figure 1 The coil-type sensor wire structure shown in Figure (1B) is as follows. Specifically, a hollow cylindrical silicone tube with open ends is used as the substrate. On the outer periphery of this substrate, two insulated wires with an outer diameter of 0.4 mm made of enameled wire are wound into a spiral shape in a consistent manner to create a wire assembly composed of double-coil wires. The outer diameter of the wire assembly is 3 mm, the length is 33 mm, and the number of turns is 42.

[0123] A differential signal is input to the sensor wires as a check signal, and the reflection coefficient between a pair of insulated wires is measured as the response signal. The measurement is performed using a Vector Network Analyzer (VNWA). At this point, one end of the pair of insulated wires constituting the wire assembly is connected to one port (port 1) of the VNWA, and the other end is connected to the other port (port 2). Then, at port 1, the reflection coefficient S is measured. 11 Measurements were conducted in the frequency range of 1–100 MHz, with the primary evaluation focused on the values ​​measured at 10 MHz.

[0124] Here, if the characteristic impedance of the pair of insulated wires constituting the sensor wire is set to Z0 in the part unaffected by the change, and the characteristic impedance of the pair of insulated wires constituting the sensor wire is set to Z in the part affected by the change, then... L Then the reflection coefficient S 11 It is represented by the following formula (1).

[0125] S 11 =(Z L -Z0) / (Z L +Z0)(1)

[0126] That is, when the characteristic impedance changes at the location affected by the changing phenomenon, the reflection coefficient also changes. Therefore, in this embodiment, the reflection coefficient is measured as a characteristic in place of the characteristic impedance.

[0127] In this experiment, firstly, to confirm the feasibility of mechanical elongation detection, the above measurements were performed under the condition of the sensor wire at its natural length without applying force, while stretching both ends of the sensor wire and the wire assembly as a single unit. The elongation of the sensor wire was determined as 100% of the natural length of the wire assembly, and the length of the wire assembly (coil length) was determined as 105%, 109%, and 116%.

[0128] In addition, to confirm the feasibility of mechanical bending detection, the same measurement was performed while bending the sensor wire. During bending, the wire assembly was integrated with the substrate, and the central axis of the sensor wire was bent into an approximately circular arc shape. The reflectance coefficient was measured in this state. The bending amount was set in 10mm increments from 50mm to 20mm, expressed as the bending diameter. A smaller bending diameter resulted in a larger bending amount and a more severe bending application.

[0129] (Experimental Results)

[0130] exist Figure 7 Regarding the case where the sensor wires are extended, the measured results of the reflection coefficient are shown for each coil length. Additionally, Table 1 below summarizes the changes in the reflection coefficient at 10 MHz.

[0131] [Table 1]

[0132] according to Figure 7 In the lower frequency region compared to the area where the reflection coefficient drops sharply near 50 MHz, the reflection coefficient is greater when the sensor wire is extended compared to the case where the sensor wire is not extended (coil length 100%). Furthermore, the greater the extension, the greater the reflection coefficient. This trend is further clearly shown in Table 1, which summarizes the changes in measured values ​​at 10 MHz. According to Table 1, the reflection coefficient increases approximately proportionally with increasing coil extension. Based on these evaluation results, it is confirmed that when the sensor wire is extended and a mechanical deformation is applied in the direction of separation between the insulated wires constituting the wire assembly, this extension can be detected as an increase in the reflection coefficient. It should be noted that... Figure 7 The sharp drop in reflection coefficient near 50MHz is caused by resonance. The change in reflection coefficient can be evaluated at lower frequencies.

[0133] Furthermore, in Figure 8 In the diagram, for cases where the sensor wires are bent, the measured reflection coefficients are shown according to the diameter of each bend. The figure is a magnified view around 10 MHz. Figure 8 The reflection coefficient is greater when the sensor wire is bent compared to when it is not bent (str). Furthermore, a trend was observed where a smaller bending diameter and a larger bending amount resulted in a higher reflection coefficient. Based on these results, it was confirmed that even when the sensor wire is mechanically bent, the bend can be detected as an increase in the reflection coefficient.

[0134] [2] Detection of temperature changes

[0135] Next, the temperature of the environment in which the sensor wire is placed was tested using coil-type sensor wires.

[0136] (Experimental Methods)

[0137] As a sample, a sensor wire was prepared. Except for the structure of the substrate, the sensor wire was designed to be the same as the coil-type sensor wire used in the above-mentioned experiment [1]. As the substrate, a substrate made by sealing both ends of a hollow cylindrical silicone tube was used. Air was sealed into the sealed space at atmospheric pressure.

[0138] The reflection coefficient was measured while the sensor wire was heated. The measurement method was the same as in the experiment [1]. During heating, the sensor wire was housed in a silicone tube, then wrapped with aluminum foil, and heated from the outside using a heater. The temperature between the silicone tube and the sensor wire was measured using a thermocouple as the temperature of the sensor wire during heating. The reflection coefficient was measured while the sensor wire was heated from 22°C (unheated state) to 72°C in increments of 10°C.

[0139] (Experimental Results)

[0140] Figure 9 This shows the measured reflection coefficient at each heating temperature. The figure is a magnified view around 10 MHz. According to... Figure 9 Compared to the case without heating (22°C), the reflectance coefficient was greater when the sensor wire was heated. Furthermore, the higher the heating temperature, the greater the reflectance coefficient. This is believed to be because, with heating, the air trapped inside the substrate expands, causing the substrate to elongate in the length direction, and the sensor wire as a whole also elongates. As confirmed in the experiment above [1], the elongation of the sensor wire causes an increase in the reflectance coefficient. Based on the above results, it is confirmed that when the sensor wire is heated, the increase in temperature can be detected as an increase in the reflectance coefficient through the elongation of the sensor wire.

[0141] [3] Detection of contact with substances

[0142] Finally, the use of spiral-shaped sensor wires to bring various substances into contact with the sensor wires was verified.

[0143] (Experimental Methods)

[0144] As a sample sensor wire, a spiral-shaped sensor wire is fabricated. Specifically, such as... Figure 1As shown in Figure (1A), a substrate is prepared, which is a plate-shaped insulating material integrally formed with a shaft. On the surface of this substrate, with the shaft as the center, two insulated wires made of enameled wire with an outer diameter of 0.4 mm are wound into a spiral shape in a consistent manner to create a wire assembly made of double-wire spiral wires. As a wire assembly, two insulated wires are laid without gaps in a roughly circular area with a diameter of 45 mm, except for unavoidable gaps.

[0145] For the aforementioned spiral-type sensor wire, the reflection coefficient was measured using the same method as in experiment [1]. During the measurement, various substances were brought into contact with the wire assembly constituting the sensor wire, and the reflection coefficient was measured. As the contact substances, an electrolyte solution (eye drops) was used as a liquid, and human fingers and two types of rubber were used as solids. During the measurement, the reflection coefficient was continuously measured while each substance was brought into contact with the wire assembly, and the time change of the reflection coefficient at a frequency of 10 MHz was recorded. It should be noted that the contact between the fingers and rubber was performed gently, and not by pressing the wire assembly with a strong force that would cause mechanical deformation.

[0146] (Experimental Results)

[0147] Figure 10 The results of the reflection coefficient measurement are shown when the electrolyte solution is in contact with the wire assembly constituting the sensor wires. Here, the change in reflection coefficient at 10 MHz is expressed as an absolute value for the case where 3 drops of electrolyte solution are dripped onto the surface of the wire assembly over time. Arrows in the figure indicate the timing of the dripping of the electrolyte solution. Furthermore, Table 2 below summarizes the change in reflection coefficient according to the amount of solution dripped. It should be noted that the position of the electrolyte solution dripping varies with each drop.

[0148] [Table 2]

[0149] according to Figure 10 As shown in Table 2, by bringing the electrolyte solution into contact with the wire assembly, the reflection coefficient increases compared to the case without contact. Furthermore, the greater the amount of electrolyte solution in contact, the greater the change in reflection coefficient. It is believed that by bringing the electrolyte solution into contact with the wire assembly, the strength of the electric field formed by the wire assembly changes, thus changing the characteristic impedance in the region where contact with the electrolyte solution occurs, and consequently, the reflection coefficient. This confirms that when a material comes into contact with a wire assembly, the contact can be detected in the form of a change in the reflection coefficient. Figure 10 In this study, the gradual increase in the reflectance coefficient after the electrolyte solution was added drop by drop is attributed to the gradual penetration of the electrolyte solution into the gaps between the insulated wires that make up the wire assembly.

[0150] Figure 11 The results of the reflection coefficient measurement are shown when a finger comes into contact with the wire assembly constituting the sensor wires. Here, the change in reflection coefficient at 10 MHz is expressed as an absolute value as the number of points of contact between the finger and the surface of the wire assembly increases from 1 to 3 over time. Arrows in the figure indicate the timing of the increase in the number of finger contact points. Furthermore, Table 3 below summarizes the change in reflection coefficient according to the number of contact points.

[0151] [Table 3]

[0152] according to Figure 11 As shown in Table 3, when a finger comes into contact with the wire assembly, similarly to when the electrolyte solution comes into contact, the reflectance increases with contact. Furthermore, the greater the number of contact points (i.e., the contact area) of the finger, the greater the change in reflectance. This confirms that contact with the wire assembly can be detected not only by liquids but also by solids, in the form of a change in reflectance. However, compared to the case of contact with the electrolyte solution, the change in reflectance is less pronounced despite the larger contact area. This can be explained by the fact that, unlike liquids, solids do not penetrate the gaps between the insulated wires constituting the wire assembly, thus the change in dielectric constant near the wire assembly is less suppressed.

[0153] at last, Figure 12 The results of reflection coefficient measurements are shown when non-conductive and conductive rubbers are in contact with the wire assembly constituting the sensor wires. Here, the reflection coefficient at 10 MHz is measured while non-conductive rubber is in contact with the surface of the wire assembly, left for a period of time, and then removed. Then, conductive rubber is in contact with the surface of the wire assembly, left for a period of time, and then removed. The periods of contact between the non-conductive and conductive rubbers are shown in the figure as regions A1 and A2, respectively. In the figure, the change in reflection coefficient at 10 MHz is expressed as an absolute value. Furthermore, Table 4 below summarizes the changes in reflection coefficient caused by the contact of each rubber. The contact area between the non-conductive and conductive rubbers is the same, and its contact area is similar to that in the above test where the finger was in contact with two points.

[0154] [Table 4]

[0155] according to Figure 12As shown in Table 4, the reflection coefficient increases regardless of whether non-conductive rubber or conductive rubber is in contact with the wire assembly. However, as seen in the results above regarding finger contact, the change is smaller compared to the case of contact with an electrolyte solution because the solid material cannot penetrate the gaps between the insulated wires constituting the wire assembly. Comparing the changes in reflection coefficient when both types of rubber are in contact, the change is greater when conductive rubber is in contact compared to non-conductive rubber. This result confirms that when the conductivity of the material in contact with the wire assembly changes, the increase in conductivity can be detected as an increase in the change in reflection coefficient.

[0156] The embodiments of this disclosure have been described in detail above, but the present invention is not limited to any of the above embodiments, and various changes can be made without departing from the spirit of the present invention.

[0157] Explanation of reference numerals in the attached figures

[0158] 1 sensor wire

[0159] 1A spiral type sensor wire

[0160] 1B coil type sensor wire

[0161] 11 Wire Assembly

[0162] 11A Dual-Wire Spiral Wire

[0163] 11B double-wire coil wire

[0164] 111 Hollow Section

[0165] 12A First Insulated Wire

[0166] 12a second insulated wire

[0167] 121 conductor

[0168] 122 insulation coating

[0169] 13 Supporting components

[0170] 131 shaft section

[0171] 2 Sensor Devices

[0172] 21 monitoring units

[0173] 25 terminating resistor

[0174] 3 wire harness

[0175] 31 object wires

[0176] B Reference Straight Line

[0177] C Contact substances

[0178] L liquid.

Claims

1. A sensor wire, The device comprises a first insulated wire and a second insulated wire, wherein the first insulated wire and the second insulated wire each have a conductor and an insulating covering that encloses the outer periphery of the conductor. The first insulated wire and the second insulated wire are bent together with their longitudinal axes aligned to form a wire assembly. The first insulated wire and the second insulated wire are considered as one unit, and there is a region on a straight line that runs through the wire assembly with multiple units of the first insulated wire and the second insulated wire arranged alternately.

2. The sensor wire according to claim 1, wherein, The first insulated wire and the second insulated wire are wound around a common central axis to form the wire assembly.

3. The sensor wire according to claim 1, wherein, In the wire assembly, the first insulated wire and the second insulated wire are assembled into a planar shape.

4. The sensor wire according to claim 1, wherein, In the wire assembly, the first insulated wire and the second insulated wire are wound into a spiral shape.

5. The sensor wire according to claim 1, wherein, The first insulated wire and the second insulated wire are both enameled wires.

6. The sensor wire according to claim 1, wherein, The sensor wire also has a support member that contacts the wire assembly and supports the wire assembly.

7. The sensor wire according to claim 6, wherein, The support member has the flexibility to deform in response to the deformation of the wire assembly.

8. The sensor wire according to claim 1, wherein, The device is equipped with a dielectric element that is connected to the wire assembly and contains a material whose dielectric constant changes due to changes in the environment surrounding the wire assembly.

9. The sensor wire according to claim 8, wherein, The change in dielectric constant is caused by at least one of a phase transition and a chemical change in the dielectric material.

10. A sensor device comprising: The sensor wire according to any one of claims 1 to 9; and The monitoring unit inputs differential signals to the first insulated wire and the second insulated wire constituting the sensor wire to obtain a response signal, and monitors changes in the response signal.

11. The sensor device according to claim 10, wherein, If the response signal changes beyond the reference, the monitoring unit determines that at least one of the following has been applied to the sensor wire: mechanical deformation, temperature change, or change in the material it is in contact with.

12. The sensor device according to claim 10, wherein, The monitoring unit monitors the change in characteristic impedance or reflection coefficient between the first insulated wire and the second insulated wire that constitute the sensor wire as the response signal.

13. The sensor device according to claim 12, wherein, The monitoring unit measures the characteristic impedance or reflection coefficient using either the time-domain reflection method or the frequency-domain reflection method.

14. The sensor device according to claim 10, wherein, The wire assembly is impedance matched to the monitoring unit by adjusting the number of groups of the first and second insulated wires arranged on the straight line.

15. A wire harness, comprising: The object is a wire, consisting of at least one wire; and The sensor device according to claim 10, The sensor wire constituting the sensor device is arranged along the length of the object wire in at least a portion of the region.

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