JP2019015534A - Cable type extension sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cable type extension sensor having high repeatability and high reliability even when used in a harsh surrounding environment while being suitable for non-destructive and continuous measurement, and extension deformation using the cable type extension sensor. To provide a measurement method. SOLUTION: This is a cable type extension sensor in which a conductor is wound around an outer peripheral portion of a core material, and the core material is a polymer material in which molecules are oriented in the length direction, and an electric signal is detected from the conductor. A cable-type extension sensor characterized by Further, it is preferable that the core material is a synthetic fiber and the tensile creep strain (25 ° C.) of the core material is 1% or less. Further, it is a method for measuring elongation deformation using the rope on which the cable-type extension sensor of the present invention is arranged and the cable-type extension sensor of the present invention. [Selection diagram] Fig. 1

Description

  The present invention relates to a cable-type extension sensor for measuring extension deformation of an object to be measured, and more specifically, a cable type suitable for ropes, fishing nets, and cable braces used in severe use environments such as in seawater and outdoors. The present invention relates to an extension sensor.

  In applications such as ropes, slings, fishing nets, and cable braces, the dangers of destruction due to fatigue deterioration due to repeated repeated external force and temporary damage due to large stress loads have been pointed out. In particular, for applications involving human lives, ensuring security and thorough maintenance management are very important.

  However, as such maintenance management work, visual inspection and sampling inspection are not enough, and there is a very high need for sensors that can grasp the deterioration change of the object by non-destructive and constant monitoring. is there.

  Thus, for example, Patent Document 1 proposes an invention of an extension sensing element that uses conductive particles in a matrix material made of a non-conductive elastomer, disperses and disperses, and uses a change in electrical resistivity of the sensor accompanying extension. . However, long-term continuation of elongation and repeated relaxation of elongation will cause plastic deformation and stress reduction in the elastomer, resulting in changes in the relative position between conductive particles and the conduction path, and the elongation rate is constant. Regardless, there is a problem that the value of the electrical resistance as the output fluctuates greatly. In addition, the electrical resistivity of the conductive particles changes with time due to surface oxidation of the metal conductive particles in the presence of ultraviolet rays, heat, environmental moisture, salt, etc., so measurement stability and reliability There was a problem of lacking.

Further, Patent Document 2 proposes a sensor that uses a metal conductive film on the surface of a thin plate-like base material having rubber elasticity and uses a change in electrical resistivity. In addition, the performance deterioration due to surface oxidation or the like, or the metal conductive film itself may be destroyed due to repeated elongation, and the measurement stability and reliability are the same.
Furthermore, many sensors using these changes in electrical resistance value have poor linearity between the elongation rate and the electrical resistance value, and the electrical resistance value changes abruptly and the effective measurement range is narrow.

Thus, for example, Patent Document 3 proposes a sensor that uses a change in inductance value instead of a change in electrical resistance value. However, these have a mechanical structure consisting of a fixed coil winding and a magnetic core that can move the relative position as the basic structure, and although the accuracy is high, the device becomes larger or heavier, ropes etc. It was not suitable for the purpose of monitoring lightweight materials.
There has not yet been proposed a sensor that can measure the elongation deformation rate of an object with high repeatability and that has high accuracy and durability reliability even under severe outdoor environments such as in seawater and the seaside.

JP 2001-50706 A JP-A-4-283602 Special table 2007-515618

  INDUSTRIAL APPLICABILITY The present invention is a cable type extension sensor that is suitable for non-destructive and continuous measurement, and has high reliability even when used in a severe ambient environment, and an extension deformation using the cable type extension sensor. It is to provide a measuring method.

The cable-type extension sensor of the present invention is a cable-type extension sensor in which a conductor is wound around the outer periphery of a core material, and the core material is a polymer material in which molecules are oriented in the length direction. An electrical signal is detected from
Furthermore, it is preferable that the core material is a synthetic fiber, the tensile creep strain (25 ° C.) of the core material is 1% or less, and the electric signal is an inductance change.
Another rope of the present invention is a rope in which the cable type extension sensor of the present invention is arranged.
Furthermore, the method for measuring extension deformation of the present invention is a method for measuring extension deformation using the cable-type extension sensor of the present invention.

  According to the present invention, the cable-type extension sensor and the cable-type extension sensor having high reliability even in use under non-destructive and continuous measurement but with high repeatability and severe ambient environment are used. A method for measuring elongation deformation is provided.

It is a conceptual diagram of the cable type | mold extension sensor of this invention. It is a conceptual diagram which shows the principle of the measuring method using the cable type | mold extension | expansion sensor of this invention. It is a graph of the displacement increment of the cable type | mold extension sensor of Example 1, and the decreasing rate of an inductance. It is a graph of the increase rate of a displacement and the decreasing rate of an inductance in the rope of Example 2.

  The cable-type extension sensor of the present invention is a cable-type extension sensor in which a conductor is wound around the outer periphery of a core material, and the core material is a polymer material in which molecules are oriented in the length direction. It is a cable type extension sensor which detects an electric signal from. It is preferable that the electrical signal corresponds to the extension rate of the cable and detects the change. Further, the detected electrical signal is preferably an inductance change.

  Here, as a core material that is a polymer material in which molecules are oriented in the length direction used in the present invention, a melted or dissolved polymer is stretched in the length direction, or obtained from a polymer in a liquid crystal state. A fiber, a film, a tape, etc. can be mentioned. From the viewpoint of physical properties, the core material is preferably a synthetic fiber. Moreover, it is also preferable that it is a cylindrical core material in which a cavity and another material exist in the center.

  And as for the core material used by this invention, it is preferable that the tensile strength measured at 25 degreeC is 0.1 GPa or more, More preferably, it is the range of 1-100 GPa, More preferably, it is the range of 3-100 GPa, Most preferably, 5 It is preferably in the range of ˜100 GPa. More preferably, the tensile strength measured at 60 ° C., which is thermally severe, is preferably 0.1 GPa or more, more preferably in the range of 1 to 100 GPa, particularly preferably in the range of 3 to 100 GPa, and most preferably 5 It is preferably in the range of ˜100 GPa. When the tensile strength is out of the above range, there is a greater concern that the cable-type extension sensor will be broken or become brittle in actual use, resulting in poor practicality. In practical use, the temperature of the cable-type extension sensor of the present invention easily rises due to temperature rise caused by direct sunlight in the outdoor environment, external force, friction, or the like.

  The core material preferably has a tensile creep (strain deformation rate) measured at 25 ° C. of 1% or less, more preferably 0.001 to 0.5%, and still more preferably 0.001 to 0.001. It is preferable to be in the range of 0.2%, particularly preferably in the range of 0.001 to 0.1%. Further, the core material preferably has a tensile creep (strain deformation rate) measured at 60 ° C., which is a more severe thermal condition, in the range of 1% or less, more preferably 0.001 to 0.5. %, More preferably in the range of 0.001 to 0.2%, particularly preferably in the range of 0.001 to 0.1%. When the tensile creep value is out of the above range, in actual use, the repeated measurement accuracy of the sensor and the stability over time are lowered and the practicality is lowered. As described above, in practical use, the temperature of the cable-type extension sensor of the present invention easily rises due to temperature rise caused by direct sunlight in the outdoor environment, external force, friction, or the like.

  In addition, it is preferable that the tensile elasticity modulus of this core material is 0.1 GPa or more, More preferably, it is the range of 1-1000 GPa, More preferably, it is the range of 10-1000 GPa, Most preferably, it is the range of 50-1000 GPa. When the tensile elastic modulus is out of the above range, in actual use, there is a greater concern that the cable-type extension sensor may be broken or embrittled due to external force deformation, resulting in poor practicality.

  Moreover, it is preferable that the diameter of a core material exists in the range of 0.02-300 mm, More preferably, it is the range of 0.04-30 mm, More preferably, it is the range of 0.06-3 mm, Most preferably, it is 0.08-0. The range is 6 mm. In addition, the diameter here is an approximate diameter, and is a value converted from the area of the cross section to the diameter of a perfect circle corresponding to the area. When the diameter of the core material is too small, it is difficult to uniformly wind the conductor around the core material, and defects such as overlapping of the conductors are likely to occur during winding. On the other hand, if the diameter of the core material is too large, flexibility and bending durability are lowered.

  The tensile elongation at break measured at 25 ° C. of the core material is preferably in the range of 1 to 100%, more preferably 2 to 50%, still more preferably 4 to 30%. More preferably, the tensile elongation at break measured at 60 ° C. is preferably in the range of 1 to 100%, more preferably 2 to 50%, still more preferably 4 to 30%. By having such an appropriate elongation, it becomes possible to effectively prevent deterioration of physical properties due to minute movement of the cable. In the sensor of the present invention, it is preferable to measure, as an electrical signal, an inductance change or the like in which a measured value varies as the core material extends. In such a case, for example, when a metal is used for the core material, the elongation is low, and an effective measurement value cannot be obtained even if the surface is insulated. On the other hand, when the elongation is too large, it is difficult to stably install the sensor, and handling in the manufacturing process tends to deteriorate.

  Moreover, it is preferable that at least the surface of this core material has electrical insulation. This is because a conductor is wound around the core member, and it is preferable to prevent an electrical short circuit between the conductor and its surroundings. In addition, when using the material which has electroconductivity for a core material, it is essential to form an electrical insulation layer in the interface of both a core material and a conductor.

  Such a core material is a polymer in which molecules are oriented as described above, and is particularly preferably an aromatic polyamide resin having excellent physical properties such as strength. In particular, it is preferably a synthetic fiber that is a fiber in which molecules are oriented in the length direction, and it is also preferred to advance the orientation of molecules by stretching.

  The synthetic fiber is preferably an aromatic polyamide fiber having high physical properties (hereinafter sometimes referred to as “aramid fiber”). Furthermore, it is a para type aromatic polyamide fiber (for example, polyparaphenylene terephthalamide fiber, manufactured by Teijin Ltd., “Twaron”), or a copolymer type para aramid fiber (for example, copolyparaphenylene-3, Preferable examples include 4′-oxydiphenylene terephthalamide fiber, manufactured by Teijin Limited, “Technola”) and the like.

  Further, in the present invention, the electrical signal is detected and the degree of extension is measured, but it is preferable that the change in the electrical signal corresponding to the extension rate of the cable is detected. Furthermore, it is preferable to use an inductance change as an electric signal. In that case, the core material preferably has a high magnetic permeability. The value of magnetic permeability can be defined as the value of relative magnetic permeability indicated by the ratio to the vacuum magnetic permeability, and is in the range of 1 to 10000, more preferably in the range of 1 to 1000, and still more preferably in the range of 1 to 100. The most preferable range is 1 to 10. Thus, when the magnetic permeability of the core material corresponding to the core of the coil is increased, the value of the inductance to be measured is relatively increased. In the sensor of the present invention, when the change in inductance is used as a measurement principle, the measurement accuracy is further increased. This is because the ratio (S / N ratio) between the magnitude of the sensor signal and the noise is also improved. However, if the magnetic permeability is too high, the absolute value of the inductance increases, the AC impedance increases, and there is a concern that a large load is applied to the electrical processing of the sensor signal, making continuous measurement difficult.

  In order to increase the magnetic permeability of the core material in this way, a method in which fine particles of a material having a high magnetic permeability are dispersed and combined in a polymer constituting the core material is preferably exemplified. Examples of such a high magnetic permeability material include permalloy, nickel, iron, ferrite, silicon steel, and carbon steel. Ferrite fine particles are particularly preferable because of good handling properties.

  The cable-type extension sensor of the present invention is a cable-type extension sensor in which the core material is a polymer material in which molecules are oriented in the length direction as described above, and a conductor is wound around the outer periphery of the core material. It is what is. The sensor of the present invention is characterized by detecting an electrical signal, particularly preferably an inductance change, from a conductor inside the sensor.

  Preferred examples of the material of the conductor used in the cable type extension sensor of the present invention include various conductive metals, such as copper, copper alloy, and aluminum. Alternatively, a metal whose surface is plated may be used. In addition, these may be described below as a conductive wire, a conductive foil wire, or a conductor wire in addition to the conductor.

  The conductor needs to conduct electricity, but its electrical resistance is preferably low. Specifically, the electrical resistance value of the conductor is preferably in the range of 0.5 to 100 μΩcm, more preferably in the range of 1.0 to 10 μΩcm. By satisfying such a range, it is possible to improve the accuracy of the sensor, reduce the power consumption, and improve the fatigue resistance against repeated elongation deformation and bending deformation of the conductor.

  As the shape of such a conductor, when the shape is close to a circle, the diameter is preferably in the range of 0.01 to 5 mm, more preferably in the range of 0.015 to 1 mm, and still more preferably in the range of 0.02 to 0.02. It is preferably in the range of 0.2 mm. When the cross section is not circular, the cross sectional area is preferably within the above range with the diameter of the same circle as the approximate diameter. Moreover, it is also preferable that it is a foil shape, and in that case, it is preferable that the thickness is in the range of 0.01 to 0.5 mm and the width is in the range of 0.1 to 5 mm. By adopting such a shape, it is possible to further improve the resistance to bending deformation and the like.

  Furthermore, it is also preferable to apply silver plating, nickel plating, or the like on the surface, and the conductor thus plated can further improve surface oxidation prevention and wear resistance. It is particularly preferable to use a so-called enameled wire in which an electrically insulating resin coating is applied to the surface of the conductor.

  However, when the measurement principle using the change in inductance is used as the electrical signal of the sensor of the present invention, it is difficult to be affected by the temporal change in the electrical resistance value due to the surface oxidation or scratching of the conductor. Even if it is not applied, it is possible to perform sufficiently stable and reliable measurement under normal circumstances.

  In addition, as the conductor of the present invention, it is also preferable to use a conductor in which windings are bundled and twisted. Thus, by using a stranded wire as the internal structure of the sensor, it is possible to further improve the durability against bending and the like. However, it is preferable to use a conductor coated with an electrical insulating layer such as an enamel wire so that conduction between the windings does not occur.

  In the present invention, these conductors are wound around the core material in a coil shape. However, in order to perform measurement with higher accuracy, it is preferable to dispose adjacent conductors so that they do not overlap. However, if the gap between adjacent conductors is too large, the absolute value of inductance, etc. will decrease and the signal / noise ratio (S / N ratio) will be insufficient, or the magnetic flux generated in the coil from a large gap Leakage tends to prevent accurate measurement. In the measurement using the sensor of the present invention, as a principle, it is preferable to use a relative change in the inductance value due to a change in the winding pitch (or the number of turns per fixed length). It tends to be a measurement error factor by inhibiting changes in the number of turns.

  In the cable type extension sensor of the present invention, the conductor is wound on the outer peripheral portion of the core material, but the gap between the conductors adjacent to each other when wound is such that the conductor is enameled or the like. In the case of so-called bare wire in which the surface of the electrical insulating layer is not applied, it is preferably in the range of 0.01 to 1 mm, more preferably 0.02 to 0.5 mm, and still more preferably 0.03 to 3 mm. A range of 0.3 mm is preferable. On the other hand, when a conductor having an electrical insulating layer such as an enamel wire is used as the conductor, the lower limit can be set to zero (in a state where they are in contact with each other). By setting it as such a range, the short circuit by the mutual contact between adjacent conductors can be prevented, and it can function as a coil winding.

  Further, the winding density of the conductor is preferably in the range of 100 to 10,000 T / m. More preferably, it is 300-6000 T / m, More preferably, it is 600-3000 T / m, Most preferably, it is preferable to set it as the range of 1000-2000 T / m. Here, since the number of turns per 1 m length (T / m) in this cable-type extension sensor is proportional to the inductance value in particular, it is generally preferable to increase the number of turns in order to increase the sensitivity of the sensor. However, if the number of turns is increased too much, the AC impedance increases as the inductance value increases, and a large load tends to be applied to the electrical processing circuit.

  The cable-type extension sensor of the present invention is one in which a conductor is wound on the outer peripheral portion of the core material as described above, and further preferably has an electromagnetic wave blocking layer on the outer layer. By providing an electromagnetic wave blocking layer, AC electromagnetic waves (electromagnetic waves whose strength changes with time) can be prevented from entering the external space, and an induced current flows through the conductor wire coil for signal detection of the sensor. It is possible to reduce the occurrence of.

  As such an electromagnetic wave shielding layer, a conductive layer having an electromagnetic wave shielding function is preferably disposed outside the wound conductor through an electrical insulating layer. It is also preferable to further provide the same type or another type of electrical insulating layer outside the electromagnetic wave shielding layer. By laminating the electrical insulation layer on the outer layer in this way, not only the reliability of the electrical insulation is increased, but also the resistance to friction with the outside is increased, the water resistance and waterproofness are increased, or the periphery is fixed. It is possible to contribute and to obtain an effect of increasing the adhesive strength.

  The electrical insulating layer is preferably made of an enamel layer, a synthetic rubber, polyimide, epoxy, silicone, polyurethane, tetrafluoroethylene, trifluoroethylene or the like. It is possible to form an electrically insulating layer by coating these resins on a conductor. The coating thickness depends on the material, but is preferably in the range of 0.01 to 3 mm, more preferably 0.05 to 2 mm, still more preferably 0.1 to 1 mm, and most preferably 0.2. It is preferable to be in the range of ˜0.5 mm. If it is too thin, it tends to be difficult to stably perform the necessary electrical insulation function. Conversely, if it is too thick, the flexibility and bending durability of the cable-type extension sensor tend to decrease.

  As a coating method for this electrical insulation layer, dip coating (a method in which a conductor wire is immersed in a layer in which a resin is dissolved in a solvent) or a melt coating method (a coating through a conductor wire in a hole filled with a molten resin) And the like) are preferred.

  And as an electromagnetic wave shielding layer, it is necessary to arrange | position a conductive layer on this electrical insulation layer. It is preferable that the conductive layer is wound without gap so that a space is not generated so as to sufficiently block external electromagnetic waves.

  The thickness of the conductive layer is preferably in the range of 0.01 to 0.2 mm, more preferably 0.015 to 0.15 mm, still more preferably 0.02 to 0.1 mm, and most preferably 0.025. It is preferable to be in the range of ˜0.75 mm. If the thickness of the conductive layer is too thin, there is a concern that the shielding performance may be reduced. Conversely, if the thickness is too thick, the overall diameter of the cable-type extension sensor also increases, which tends to cause a decrease in flexibility and bending durability.

  Furthermore, it is preferable to provide a protective layer outside the electromagnetic wave shielding layer. Performances such as prevention of scratches, fraying prevention and oxidation resistance of the electromagnetic wave shielding layer are improved. In addition, the cable type extension sensor of the present invention also provides surface protection, wear countermeasures, ensuring electrical insulation, improved water resistance, and the like.

  As a protective layer, the thing similar to said electric insulation layer can be used, and it is preferable that the thickness of a protective layer shall be the range of 0.01-3 mm. More preferably, it is 0.05-2 mm, More preferably, it is 0.1-1 mm, Most preferably, it is preferable that it is the range of 0.2-0.5 mm.

  And as a whole thickness of the cable type | mold extension | expansion sensor by which the conductor was wound by the outer peripheral part of the core material of this invention, a diameter exists in the range of 0.1-3000 mm (0.1 mm-3m). More preferably, it is preferably in the range of 0.3 to 30 mm, more preferably in the range of 0.5 to 10 mm, and most preferably in the range of 0.8 to 5 mm. By setting it as such a range, it can be used as a sensor cable excellent in durability, stability, and incorporation.

  Moreover, the length of the cable type | mold extension sensor of this invention can be suitably determined according to a measurement use, and is used in the range of 1-10 million mm (1 mm-10 km) in many cases. For example, a range of 1000 to 10000000 mm (1 m to 10 km) is generally preferred in applications where the entire rope is incorporated. In the case of an application incorporated in a part of the rope, it is preferably in the range of 10 to 100000 mm (10 mm to 100 m).

  Such a cable-type extension sensor of the present invention is incorporated in the whole or a part of an object (measurement object, for example, a cable) whose extension is to be measured, or a surface layer of the whole or part of the object (measurement object). The degree of extension of the object (object to be measured) can be measured (monitored) by being fixed to and disposed on.

  In addition, when the cable type | mold extension sensor of this invention is used for the purpose of measuring the extension degree of the said part (or representative part) of a target object (measuring object) here as "a part of a target object" here, For the purpose, it is measured by incorporating an extension sensor cable only in a portion to be measured that is required, or by fixing the surface layer. When the entire object (measurement object) (entire area) is to be measured, one or a plurality of sensors are incorporated in an appropriate orientation in the “entire” (entire area) of the object, or the surface layer. Needless to say, measurement can be performed in a fixed manner.

  As a method for incorporating the cable-type extension sensor of the present invention into the object (object to be measured) or a surface layer fixing method, it is preferable that the extension deformation of the object to be measured and the extension degree of the cable-type extension sensor are matched or substantially matched. . Specific examples include a method of providing an adhesive resin layer having an adhesive function at the interface between the two, a fastening method using a fixing metal fitting, and a fastening method using a fiber having a binding force.

  Further, in particular, when the object (measurement object) has a fiber or a fiber aggregate structure such as a cable, as a method for incorporating the cable type elongation sensor therein, for example, the cable type elongation sensor is a fiber or fiber aggregate. By arranging the structure in contact with each other and then twisting it, the twisting force of the twisting process generates a large pressure and friction force between the sensor and the fiber or fiber assembly. Can be created in a mutually fixed state. In order to further ensure mutual fixation, it is preferable to provide an adhesive resin layer having an adhesive function at the interface between the sensor and the fiber or fiber assembly.

  The adhesive resin layer used when fixing the cable type extension sensor of the present invention to an object (measuring object) is not greatly restricted, but the heat resistance temperature of the core wire and the covering resin layer included in the cable sensor layer configuration is considered. Therefore, it is preferable to use a thermosetting resin that cures at a temperature of 220 ° C. or lower, or a thermoplastic resin that has a softening temperature of 220 ° C. or lower. By using such a resin, the resin is softened or melted by heating, and it becomes easy to adhere or fuse at the interface between them. Examples of preferred resins here include polyurethane, unsaturated polyester, vinyl ester, acrylic-based, phenol-based, epoxy-based, and silicone-based resins. Thermoplastic resins include: Polyethylene, polypropylene, nylon, polycarbonate, modified resins thereof, and the like can be preferably used.

As a method for disposing these adhesive resin layers, for example, the cable type extension sensor of the present invention, the fiber of the object (measuring object) or the outermost layer of the fiber assembly before coating is pre-coated. Or a method of injecting and impregnating a necessary site after incorporation from the outside.
Another rope of the present invention is a rope in which the cable type extension sensor of the present invention is arranged.
Next, a method for measuring extension deformation using the cable type extension sensor of the present invention will be described.

  In the method for measuring extension deformation, which is one of the present invention, the cable-type extension sensor in the cable-type extension sensor is installed after the cable-type extension sensor of the invention is installed on the object (measurement object) as described above. From the change in the electrical signal detected from the body, the extension deformation of the object (measurement object) is measured. More specifically, the electrical signal is optimally an inductance change. This is because the change in the inductance of the winding of the conductor and the change in the extension rate of the cable-type extension sensor have stable linearity (linear change), so that the measurement accuracy can be increased.

Now, the relationship between the extension of the coiled conductor and the decrease in inductance can be described with reference to FIG. Here, the initial coil length is D (m), the current is I (A), the coil cross-sectional area is S (m ² ), the total number of turns is N, and the number of turns per unit length is n = N / D. did.

The self-inductance L (H) of the coil is obtained when the permeability is μ (N / A ² )
L = μN ² S / D
It is expressed.
(The magnetic field H (N / Wb) inside the coil is the current I,
H = nI
The magnetic flux density B (Wb / m ² ) inside the coil is B = μH = μnI
Magnetic flux Φ ₀ (Wb) penetrating the coil cross-sectional area S (m ² ) is
Φ ₀ = B · S = μnIS
In the coil having the initial length D and the total number of turns N, the magnetic flux Φ ₀ intersects with the coil having the total number of turns N.
Φ = N · Φ ₀ = N · μn IS = N · μ (N / D) IS = μN ² SI / D
The self-inductance L (H) of the coil is
L = Φ / I = μN ² S / D)

Here, the self-inductance L ′ (H) of the coil after being stretched at the stretch rate e is
L ′ = μN ² S / D (1 + e)
It is expressed.

  Therefore, the self-inductance decreases with 1 / (1 + e) with respect to the expansion rate e, and when e is sufficiently small, 1 / (1 + e) can be approximated to 1-e (note that the cross-sectional area S is the core inside the coil). (S≈S ′ since there is a material (fiber) and deformation to the inside of the coil is suppressed).

  That is, the inductance change of the conductor winding detected by the cable type extension sensor of the present invention is the change in the extension rate of the cable type extension sensor and the change in the electrical resistance value when the extension rate e is sufficiently small. In this case, there is stable linearity (linear change close to a proportional relationship), and the measured value is linearly correlated with the elongation deformation rate, and the measurement accuracy is very high.

  Therefore, as a specific measuring method of the present invention, the cable type extension sensor of the present invention capable of electrically measuring the expansion / contraction deformation rate is arranged adjacent to the measured object (for example, the positions of two or more different points). ) To measure the expansion / contraction deformation ratio of the measured object from the measurement data of the expansion / contraction deformation ratio of the cable-type extension sensor. Is the method. Here, as a method of electrically measuring the expansion / contraction deformation ratio, the expansion / contraction deformation ratio in the winding length direction of the conductor in the sensor is changed by the winding pitch change (change in the number of turns per fixed length). It is preferable that the calculation be performed in correlation with the inductance change associated with. An electrical processing circuit provided outside the sensor can measure the change in inductance of the conductor winding in the sensor.

  The electrical processing circuit used here is a device that measures, as an electrical parameter, a change in inductance or the like of a winding to be detected in the cable-type extension sensor of the present invention. In order to measure the electrical signal, an electrical processing circuit electrically connected to both ends of the conductor winding in the sensor is provided outside the winding (generally outside the sensor). In this electric processing circuit, other methods such as a two-terminal method can be used, but it is preferable to perform inductance measurement and processing based on a four-terminal method based on a regular method. More specifically, an AC voltage is applied to the sensor winding and the current response of the sensor winding is examined, or an AC current is applied to the sensor winding and the sensor winding voltage response is examined. Therefore, it is preferable that the inductance is measured.

  Furthermore, when the cable type extension sensor of the present invention has an electromagnetic wave shielding layer, it is preferable to electrically connect the electromagnetic wave shielding layer to the ground terminal of the electric processing circuit. It is possible to more effectively block external electromagnetic waves (noise) entering the sensor winding.

  Although there is no particular limitation on the frequency of the AC signal used for this measurement, a frequency band in the range of 100 kHz to 10 MHz is particularly preferable, and impedance change can be measured with a better S / N ratio.

  Regarding such an electric processing circuit, it is preferable to design a circuit in accordance with this purpose, but it is also possible to use a measuring instrument such as a commercially available impedance analyzer for simplicity.

  From the information such as impedance change obtained by such a measuring method, the elongation deformation rate of the winding can be easily calculated based on the above-mentioned principle and the like. The obtained impedance information and calculation data for the elongation deformation rate of the winding are preferably transmitted remotely via wire, wireless, etc. as necessary, and can be used for monitor management and control purposes in various applications.

  In addition, since the cable-type extension sensor of the present invention requires the conductor winding structure as described above, the conductor itself that is the center of measurement in the sensor directly measures the stress (tension) when the sensor is extended. This is a factor that increases the long-term reliability of the cable-type extension sensor of the present invention.

  It is also preferable that a plurality of the cable type extension sensors of the present invention are arranged in parallel. When the sensors are configured in such a parallel arrangement, a plurality of measurement points can be selected, and channels can be freely selected as necessary. In addition, it is possible to average the inductance value, which is a measurement value, by making the parallel circuit of the sensor, the data stability is improved, and the operation such as integration of the reciprocal circuit for the return / return of the electric signal becomes possible. As described above, by adopting a cable integrated structure in which a plurality of the extension sensors of the present invention are arranged in parallel to each other, it is possible to improve a more practical electric circuit design and measurement reliability.

  Such a cable type extension sensor of the present invention has a structure in which a conductor is wound in a coil shape around a core material made of a polymer material, and the winding pitch change of the conductor when the structure is extended. This is a cable-type extension sensor that is excellent in temporal reliability and repeated measurement accuracy based on the principle of measuring (change in the number of turns per fixed length) as a change in electrical signal. And this cable type extension sensor can be used as a rope, sling, fishing net, cable brace, various building structures, various structural materials for transportation equipment, etc. which are placed inside, and it has excellent durability and reliability. It is particularly useful when used in harsh environments such as outdoor use where it is exposed to wind or rain or sunlight.

  And, it is a method that can measure the elongation deformation of these measured objects in a non-destructive and real-time manner with high repeatability and high reliability, and data relating to deformation or destruction phenomena of the measured objects Is a method that can always be collected with high accuracy.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited only to a following example. In addition, the measurement in an Example is calculated | required with the following method.

(1) Tensile creep strain Tensile creep strain was measured according to a measurement method defined in JIS K 7115, which is a standard for plastic molded products. However, in general, when measuring a fiber or cable-shaped test piece using a tensile measuring machine for creep evaluation, it is difficult to secure the contact area (friction fixed area) between the chuck and the test piece. Instability related to King (influence of specimen sliding or mechanical fulcrum instability) often occurs. Considering this, the following procedure is adopted in the test measurement of this example.

  That is, before applying the test load to the test piece, measurement was performed by applying a minimum load as a preliminary load that allows the test piece to be stretched between the chucks of the tester without slack. This preload continued to be applied during the creep test. When the test piece was a fiber material, it was tested in accordance with JIS L 1013 so that no slip would occur due to chucking between the test piece and the gripping tool of the testing machine during the tensile test.

  The test load (total load) was a load corresponding to 30% of the tensile strength (breaking strength) of the test piece measured according to JIS L1013 in the case of fiber filaments and JIS K 7161 in the case of plastic molded products. .

  Set the test temperature and humidity conditions of the testing machine with the preload applied, and after reaching the set values, leave it for 2 hours to allow the test piece to fully adapt to the test temperature and humidity conditions. Applied. In this example, for the above-mentioned reasons, all the tests were conducted by setting the start point time (t = 0) of the tensile creep strain displacement measurement 5 minutes after the test load application.

(2) Stability over time It was performed under the condition that a load corresponding to 30% of the tensile strength (breaking strength) obtained in (1) above was applied as a test load (full load). The duration of this full load was set to a maximum of 10 hours (however, when the test piece broke, it was terminated at that point).
The test atmosphere temperature at the time of measurement was 25 ° C. and 60 ° C. The humidity was controlled in the range of 25 ± 3 ° C. and 50 ± 5% RH as the temperature and humidity conditions of the measurement chamber where the testing machine was placed.

[Example 1]
(Creation of cable type extension sensor)
Copolymer aromatic polyamide fiber yarn having a fineness of 110 dtex (copolyparaphenylene-3, 4'-oxydiphenylene terephthalamide fiber yarn, manufactured by Teijin Ltd., "Technora", long fiber filament constituting fiber as the core material Forty-eight fibers, an approximate diameter of the fiber bundle of 0.1 mm, a tensile modulus of 74 GPa, a tensile strength of 3.4 GPa, a breaking elongation of 4.5%, and a magnetic permeability of about 1.0) were used. The tensile creep strain after 10 hours of this product was 0.3% or less under both conditions of room temperature 25 ° C. and high temperature 60 ° C.

On the other hand, a tape-like copper foil wire was prepared by slitting a silver-plated copper foil having a thickness of 0.035 mm to a width of about 0.5 mm as a conductive material. The electrical resistance value of the conductive material was 1.5 μΩcm.
Using a fiber yarn as a core material and using a covering machine, a silver-plated copper foil wire was used as a conductor to obtain a winding wound under a winding number condition of 1500 T / m. The diameter of the obtained winding was 180 μm, the copper foil wire was spirally wound around the core, and there was a gap of 0.133 mm between the copper foils.

Next, a resin coating layer made of a silicone resin having a thickness of 0.2 mm is coated around the obtained winding as an electrical insulating layer, and further, a thickness of 0.035 mm and 0.5 mm is formed on the surface of the electrical insulating layer. A nickel-plated copper foil wire with a width was used as an electromagnetic wave shielding layer wound twice under the condition of 2500 turns / m. In this electromagnetic wave shielding layer, the nickel-plated copper foil wire is wound around the entire surface of the resin-coated electrical insulating layer without any gap.
In this manner, a conductor having a diameter of 0.9 mm was obtained in which the conductor was wound on the outer peripheral portion of the core material and the electric insulating layer was provided on the outermost surface.
Next, the obtained cable was cut at a total length of 3500 mm to obtain a cable-type extension sensor.

(Performance evaluation of cable type extension sensor)
And the silver plating copper foil wire used for the coil | winding was taken out from the both ends of this cable type | mold extension | expansion sensor, and it connected to the measurement terminal of the impedance meter (made by Keysight Technology LLC). Next, nickel-plated copper foil wires used for the electromagnetic wave shielding layer were also drawn separately from both ends and connected to the ground potential terminal of the impedance meter.

  Then, a tensile test using a universal testing machine was performed on the central part 500 mm length of the total length of 3500 mm of the cable-type extension sensor, and the change in inductance with respect to the tensile displacement was examined. The inductance was measured under the condition of a frequency of 2 MHz.

  In addition, regarding the chucking of the sample of the test machine, the sample was scratched and fixed to prevent the sample from being scratched or slipping at the chuck portion against tension, thereby enabling stable measurement. In addition, after setting the sample and before starting the measurement, the wiring part between the universal tester chuck and the impedance meter terminal is artificially moved several times to change the closed circuit area of the measurement line by a factor of about 2 to change the inductance. As a result, the fluctuation was less than 0.1%. That is, no significant change in inductance was observed even when the closed circuit area was changed, and it was confirmed that the electromagnetic wave shielding layer shielded the external electromagnetic noise from being hardly affected by the external electromagnetic noise.

  In the tensile test, the maximum tensile displacement is 21 mm, and the tensile force application ⇒ unloading (relaxation) ⇒ tensile force application ⇒ unloading (relaxation) cycle is repeated four times. The rate of decrease in inductance (%) at 2 MHz relative to the displacement increment (%) for the total length of 3500 mm was measured. FIG. 3 shows a graph for a region where the displacement increment is 0.5% or less. In this region, as shown in FIG. 3, the displacement increment (%) and the inductance decrease rate (Inductance reduction cable) (%) show a linear change. But stability was high.

Furthermore, in order to investigate the temporal stability of this cable type extension sensor, the tensile strength (breaking strength) of the core material was maintained for 10 hours with a 30% load applied, and changes in tensile strain and inductance values were observed. . In the 25 ° C. measurement, the tensile strain increased by 0.2% (increase from 1.7% to 1.9%), and the inductance value decreased by 0.2%. Even at 60 ° C., the tensile strain increased by 0.2% (increased from 1.9% to 2.1%), and the inductance value decreased by 0.2%.
From these results, it is determined that the performance as a cable-type extension sensor is very stable and highly reliable.

[Example 2]
The cable-type extension sensor obtained in Example 1 was placed in the center of a fiber rope having a diameter of about 5 mm to obtain a measurement object.

  The rope to be measured is composed of 100 fiber yarns having a fineness of 1670 dtex, a filament constituting fiber number of 1000, and an approximate diameter of about 0.4 mm. As the fiber constituting the fiber yarn, the same copolymer aromatic polyamide fiber (copolyparaphenylene-3, 4'-oxydiphenylene terephthalamide fiber, manufactured by Teijin Ltd., "Technora") used for the core material )It was used.

  This fiber yarn having a fineness of 1670 dtex was placed on a krill stand, and each yarn was pulled out from a total of 100 fiber bobbins. Then, the position is controlled so that the cable-type extension sensor is arranged at the center of the rope of the object to be measured, and the cable-type extension sensor is pulled out from the krill stand, so that a total of 100 fiber yarns having a fineness of 1670 dtex cover the circumference of the cable-type extension sensor. Then, a test rope having a cable-type extension sensor disposed therein was created. At this time, the cable type extension sensor was in a state of being substantially fixed in the fiber rope by the other 100 fiber yarns.

  After the rope of the object to be measured was cut to a total length of 3500 mm, the extension sensor cable was pulled out from the end, and in the same manner as in Example 1, the tensile displacement increment (%) with respect to the total length of the rope of 3500 mm and the inductance reduction rate at 2 MHz When the correlation of (%) was measured, it was as shown in FIG. Except that almost no decrease in inductance was observed in the initial tensile region where the tensile displacement was small, a linear correlation was obtained in the same manner as described above, and it was stable against repeated tensile and relaxation.

[Example 3]
On the outside of the electromagnetic wave shielding layer of the cable type extension sensor obtained in Example 1, an insulating coating layer made of a silicone resin having a thickness of 0.2 mm was formed again to form a cable type extension sensor having a diameter of 1.3 mm. .
Using this cable type extension sensor, a rope was created in the same manner as in Example 2 and performance evaluation was performed. As a result, a linear correlation was obtained in the same manner as in Example 2, and the tension and relaxation were repeated. However, the sensor output was stable and excellent in durability.

[Example 4]
In place of the copolymerized aromatic polyamide fiber yarn of Example 1 as a core material, an ultrahigh molecular weight polyethylene fiber yarn having a fineness of 1760 dtex (filament yarn approximate diameter 0.5 mm, tensile elastic modulus 88 GPa, tensile strength 2.7 GPa A cable type extension sensor was prepared in the same manner as in Example 1 except that 3.5% elongation at break and 2000 filaments were used), and performance evaluation was performed in the same manner as in Example 1. It was. The tensile creep strain of the ultrahigh molecular weight polyethylene fiber used for the core material was 0.9% at room temperature and 30% at 60 ° C. measurement.
Regarding the evaluation as a sensor, the cable displacement increment (%) and the inductance decrease rate (%) showed a linear change and were usable as a cable-type extension sensor.

  However, in order to investigate the temporal stability of this cable type extension sensor, as in Example 1, it was held for 10 hours with a 30% load of the tensile strength (breaking strength) of the core material applied, and the tensile strain and inductance The change in value was observed. As a result, in the 25 ° C. measurement, the tensile strain increased by 0.9% (increase from 1.6% to 2.5%), and the inductance value decreased by 1.0%.

  On the other hand, in the 60 ° C. measurement, a large elongation that can be confirmed with the naked eye occurs during the test, and the cable breaks after 5 hours. The reliability as the cable-type elongation sensor is relatively low compared to Example 1. It was.

1. Conductive material
2. 2. Core material Electrical insulation layer (resin coating layer)
4). Electromagnetic shielding layer

Claims (6)

  A cable-type extension sensor in which a conductor is wound around the outer periphery of a core material, wherein the core material is a polymer material in which molecules are oriented in the length direction, and an electrical signal is detected from the conductor. Cable type extension sensor.   The cable-type extension sensor according to claim 1, wherein the core material is a synthetic fiber.   The cable-type extension sensor according to claim 1 or 2, wherein the core material has a tensile creep strain (25 ° C) of 1% or less.   The cable-type extension sensor according to claim 1, wherein the electrical signal is an inductance change.   The rope which has arranged the cable type extension sensor according to any one of claims 1 to 4. The measuring method of the extension deformation | transformation using the cable type extension sensor of any one of Claims 1-4.

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