JP7068569B2 - Tension sensor - Google Patents

Description

The present invention relates to a tension sensor.

A wide variety of tensile sensors that are attached to a detection target and detect movements such as elongation of the detection target have been known in the past, and as disclosed in Patent Document 1 in recent years, they are not conductive fibers. Tension sensors are being developed that are constructed as knits or woven fabrics made of blended yarns mixed with conductive fibers.

The tension sensor disclosed in Patent Document 1 makes a knit or woven fabric including a plurality of conductive yarns expandable and contractible in one direction, and expands and contracts between the conductive yarns so as to maintain an insulated state. This is an attempt to detect a change in capacitance from the accompanying change in spacing. According to such a tension sensor, since the expansion and contraction of the knitted fabric or the woven fabric is detected as the capacitance, no current flows even if a voltage is applied to the conductive yarn, and the power consumption in this portion can be set to zero. , Power consumption can be suppressed.

Japanese Unexamined Patent Publication No. 2012-177565

However, since the tension sensor disclosed in Patent Document 1 described above is configured only as a woven fabric or a knitted fabric, its elasticity is likely to be impaired by continuous use and expansion and contraction, and its elasticity is likely to be impaired for a long period of time. There is a problem that it is difficult to accurately detect the deformed state of the object to be detected, the presence or absence of an acting tensile force, and the value of the tensile force.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a tensile sensor whose detection accuracy does not easily decrease even if the use is continued.

An object of the present invention is to have a dielectric layer having elasticity and containing a thermoplastic elastomer, and an elastic first conductive layer and second conductive layer provided on one surface and the other surface of the dielectric layer, respectively. The first conductive layer includes a strip-shaped first electrode portion formed of a conductive thread, and the resistance change rate of the first electrode portion when stretched by 50% is 20% or less. This is achieved by a strip-shaped tensile sensor capable of detecting a change in capacitance between the first conductive layer and the second conductive layer due to expansion and contraction.

In this tension sensor, it is preferable that the first electrode portion has a knitted fabric structure containing at least the conductive yarn.

Further, the second conductive layer includes a band-shaped second electrode portion formed of a conductive thread, and the second electrode portion is located at a position facing the first electrode portion via the dielectric layer. It is preferable that it is arranged in.

Further, the first conductive layer includes a plurality of the first electrode portions, the first electrode portions are arranged in parallel with each other at predetermined intervals, and the second conductive layer is the second electrode portion. A plurality of portions are provided, the second electrode portions are arranged in parallel with each other at predetermined intervals, and the first electrode portions and the second electrode portions face each other with the dielectric layer interposed therebetween. It is preferable that they are arranged.

Further, it is preferable that the second electrode portion has a knitted fabric structure containing at least a conductive yarn.

Further, the second conductive layer includes a second electrode portion having an area larger than the area of the first electrode portion, and the second electrode portion has the first electrode portion via the dielectric layer. It is preferable that it is arranged at a position facing the.

Further, the first conductive layer includes a plurality of the first electrode portions, the first electrode portions are arranged in parallel with each other at predetermined intervals, and the second conductive layer has the plurality of first electrode portions. A second electrode portion having an area larger than the area of the region where the one electrode portion is arranged is provided, and the second electrode portion is arranged with the plurality of first electrode portions via the dielectric layer. It is preferably arranged at a position facing the region.

Further, it is preferable that the conductive yarn is covered with an insulating coating layer.

The insulating coating layer includes polyurethane, polyvinyl chloride, polypropylene, polyethylene, nylon, polyester, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ether ketone, PFA, PVDF, ETFE and other fluororesins, and polystyrene. It is preferably formed from at least one selected from the group of polycarbonate, polyethylene sulphon, polyether sulphon, formal (polyvinyl formal), butyral (polyvinyl butyral).

Further, the dielectric layer is preferably formed of urethane rubber.

Further, the dielectric layer preferably contains a stretchable fabric.

Further, it is preferable that the first electrode portion has stretch anisotropy.

Further, it is preferable that the first electrode portion is configured such that the dimensional change rate in the lateral direction when extended by 50% in the longitudinal direction is less than 5%.

According to the present invention, it is possible to provide a tensile sensor whose detection accuracy does not easily decrease even if the use is continued.

(A) is a schematic configuration plan view showing a tension sensor according to the present invention, (b) is a schematic configuration sectional view showing a cross section thereof, and (c) is a schematic configuration back view. It is an example which shows the knitted fabric cross section of the 1st electrode part and the 2nd electrode part provided in the tension sensor which concerns on this invention, (a) is in the non-extended state, and (b) is in the extended state. (A) is a schematic configuration plan view showing a modified example of the tension sensor according to the present invention, (b) is a schematic configuration sectional view showing an A'-A'cross section, and (c) is a schematic configuration back view. be. It is a schematic structural sectional view which shows the modification of the tension sensor which concerns on this invention. It is a schematic structural sectional view which shows the modification of the tension sensor which concerns on this invention. Both (a) and (b) are schematic structural sectional views showing a modified example of the tension sensor according to the present invention. It is a schematic structural sectional view which shows the modification of the tension sensor which concerns on this invention. (A) is a schematic configuration plan view showing a sensor sample A of the tension sensor according to the present invention, (b) is a schematic configuration sectional view showing an A "-A" cross section, and (c) is a schematic configuration back view. Is. It is a graph which shows the relationship between the elongation rate of the sensor sample A, and the value of the detected capacitance. It is a graph which shows the relationship between the elongation rate of a sensor sample B, and the value of the detected capacitance.

Hereinafter, the tension sensor according to the embodiment of the present invention will be described with reference to the accompanying drawings. The drawings are partially enlarged or reduced to facilitate understanding of the configuration. 1 (a) is a schematic structural plan view of the tension sensor 1 according to the present invention, and FIG. 1 (b) is a schematic structural sectional view showing a cross section taken along the line AA of FIG. 1 (a). Further, FIG. 1 (c) is a schematic configuration back view seen from the direction of arrow B in (b). The tension sensor 1 according to the present invention is, for example, a biological sensor that acquires breathing information of a living body (for example, presence / absence of breathing, breathing cycle, etc.) and body movement information (for example, information on movement of limbs), or deformation of an object. It is a sensor that can be used as a strain sensor for detection, and as shown in FIGS. It includes a first conductive layer 3 and a second conductive layer 4 provided on one surface and the other surface, respectively. The tensile sensor 1 constitutes a capacitor by a dielectric layer 2 and a first conductive layer 3 and a second conductive layer 4 sandwiching the dielectric layer 2 in between, and is a first conductive layer that accompanies expansion and contraction. It is a sensor capable of detecting a change in capacitance between 3 and the 2nd conductive layer 4.

The dielectric layer 2 is configured to have elasticity, and also has an insulating property that does not energize the first conductive layer 3 and the second conductive layer 4 even when they are in contact with each other. It is configured in. The electrical resistivity of the dielectric layer 2 is preferably ¹⁰⁶ Ω · cm or more and 10 ¹⁸ Ω · cm or less. The form of the dielectric layer 2 is not particularly limited, and may be formed in the form of a sheeted film, or may be formed in the form of a knitted fabric, a woven fabric, a non-woven fabric, or the like.

Further, as the material of the dielectric layer 2, a thermoplastic elastomer can be exemplified. In particular, urethane rubber, natural rubber, isoprene rubber, butadiene rubber, styrene / butadiene rubber, butyl rubber, nitrile rubber, ethylene / propylene rubber, chloroprene rubber, acrylic rubber, chlorosulfonated polyethylene rubber, silicone rubber, fluororubber, ethylene / acetic acid. Examples thereof include various rubber materials such as vinyl rubber and epichlorohydrin rubber. Moreover, you may add an additive to the said material. For example, dielectric constant adjustment, a softening plasticizer, an additive that makes it easy to stretch, and the like can be mentioned. As the additive, it is necessary to select a material that does not break down the dielectric layer 2.

Further, for example, urethane foam rubber may be used as the material for forming the dielectric layer 2, and the dielectric layer 2 may be formed in the form of a sponge having minute voids inside. With such a sponge-like structure, the dielectric layer 2 can easily return to its initial form (form before elongation) when the pulled state is released.

Here, the thickness of the dielectric layer 2 is not particularly limited, but is preferably set in the range of 5 μm to 1000 μm, and more preferably set in the range of 10 μm to 750 μm. Further, it is more preferable to set it in the range of 20 μm to 500 μm. By setting it in such a numerical range, it is possible to obtain preferable elasticity while effectively preventing the material from being easily broken by tension.

As shown in FIGS. 1A, 1B, and 1C, the first conductive layer 3 includes a strip-shaped first electrode portion 31, and strip-shaped first non-conductive portions 32 on both sides of the first electrode portion 31. It is configured with. The second conductive layer 4 has the same structure as the first conductive layer 3, includes a band-shaped second electrode portion 41, and has strip-shaped second non-conductive portions 42 on both sides of the second electrode portion 41. It is configured in preparation. The longitudinal direction of the first electrode portion 31 and the first non-conductive portion 32 of the first conductive layer 3 and the longitudinal direction of the second electrode portion 41 and the second non-conductive portion 42 of the second conductive layer 4 are. It is set so as to be in the direction along the longitudinal direction of the strip-shaped tension sensor 1. Further, the extension direction of the strip-shaped tension sensor 1 is not particularly limited, but it is preferable to configure the strip-shaped tension sensor 1 so that it can be extended at least along the longitudinal direction of the tension sensor 1.

Such a first conductive layer 3 is configured to have elasticity, for example, for forming a conductive thread for forming the first electrode portion 31 and each first non-conductive portion 32. It is preferable to configure it as a knitted or woven fabric (knitted fabric) using a non-conductive yarn. The same applies to the second conductive layer 4, and knitting or weaving is performed using the conductive yarn for forming the second electrode portion 41 and the non-conductive yarn for forming each of the second non-conductive portions 42. It is preferable to configure it as a dough. In the present embodiment, the first conductive layer 3 (first electrode portion 31 and the first non-conductive portion 32) and the second conductive layer 4 (second electrode portion) are used as a fabric having a knitted fabric structure formed by knitting. 41 and the second non-conductive portion 42) are formed. The knitted fabric structure is not particularly limited, and for example, milling, smooth, pearl, flat or their changing structure (for example, Milan ribs, corrugated cardboard knits, etc.), tricots, raschels, Miranys, etc. Various knitted fabric structures can be adopted. Further, when the first conductive layer 3 and the second conductive layer 4 are configured as a woven fabric, a weave such as a plain weave, a twill weave, or a satin weave can be exemplified as the woven fabric structure. The method for manufacturing the first conductive layer 3 and the second conductive layer 4 is not limited to the above method. For example, the fabric body is first knitted or woven with non-conductive fibers, and then the conductive yarn is woven into a predetermined portion. Alternatively, the first electrode portion 31 (or the second electrode portion 41) can be formed and manufactured by embroidery or the like.

Here, examples of the conductive threads for forming the first electrode portion 31 and the second electrode portion 41 include aluminum, nickel, copper, titanium, magnesium, tin, zinc, iron, silver, gold, platinum, and vanadium. , Pure metals such as molybdenum, tungsten, cobalt, their alloys, thread-like or strip-shaped metal wires formed of stainless steel, brass, etc., and threads formed of conductive fibers such as carbon fibers can be used. .. Further, a covering yarn in which a synthetic fiber (for example, polyester fiber, nylon fiber, etc.) or a natural fiber is used as a core and a metal fiber is wound around the core may be used as a conductive yarn. In addition, a metal-coated yarn (plated yarn) in which a synthetic fiber, a natural fiber, or the like is used as a core, and a metal component is adhered to the core by performing wet or dry coating, plating, vacuum film formation, or other appropriate coating method. ) Can be used as a conductive yarn. Although it is possible to use a monofilament for the core, a multifilament or spun yarn, which is an aggregate of a plurality of single fibers, is preferable to a monofilament, and further, a woolly processed yarn or a covering yarn such as SCY or DCY. , Bulk processed yarns such as fluffed yarns are more preferable. The metal components to be adhered to the core include pure metals such as aluminum, nickel, copper, titanium, magnesium, tin, zinc, iron, silver, gold, platinum, vanadium, molybdenum, tungsten and cobalt, their alloys, and stainless steel. , Brass, etc. can be used.

The thickness of the conductive yarn is not particularly limited, but the wire diameter per single wire is preferably, for example, 10 to 100 μm. Above all, when it is set to 10 to 50 μm, the flexibility and durability of the first conductive layer 3 and the second conductive layer 4 itself (the first electrode portion 31 and the second electrode portion 41 itself) are easily compatible with each other, which is particularly preferable.

When a metal wire is used as the conductive thread, the surface thereof may be covered with an insulating coating layer. The metal wire coated with the insulating coating layer may be a monofilament or a multifilament, and it is particularly preferable to bundle 2 to 9, more preferably 3 to 7, and use it as one thread. By covering the metal wire with the insulating coating layer in this way, the change in resistance when the tensile sensor 1 expands and contracts becomes small, and it becomes possible to accurately detect the change in capacitance due to expansion and contraction. Further, the waterproofness and durability are improved, and the tension sensor 1 that can be used for a long period of time can be obtained.

There is no time to list the specific names of materials that can be used as the insulating coating layer, but one example is as follows. That is, it is a general term for polyamide-based synthetic fibers such as polyurethane, polyvinyl chloride, polypropylene, polyethylene, and nylon (nylon 6, nylon 66, etc., which are made into fibers by spinning long continuous chain-like synthetic polymers by amide bond. ), Polyester, Polyester terephthalate, Polybutylene terephthalate, Polyphenylene sulfide, Polyether ether ketone, PFA, PVDF, ETFE and other fluororesins, Polystyrene, Polycarbonate, Polysulphon, Polyethersulphon, Formal (polyvinylformal), Butyral (polyvinyl) Butyral) and so on. The material that can be used as the insulating coating layer is not limited to these resin types. Further, a metal wire insulatingly coated with a resin as exemplified is also called an enamel-coated metal wire.

As a method of covering the metal wire with the insulating coating layer, a general coating method from application of the molten material to drying may be adopted. In addition, covering yarn (SCY or DCY) is used as a core material of a metal wire and a fibrous (thread-like) insulating coating material (for example, a thread or cotton thread formed from a material that can be used as the above-mentioned insulating coating layer) as a covering material. It is also possible to adopt a method of forming the coating, a method of heating and melting the covering yarn to form a coating film, and the like.

Further, in the conductive yarn coated with the insulating coating layer, the material forming the insulating coating layer has flexibility and elasticity in addition to melting at the melting temperature of the solder (approximately 170 ° C to 250 ° C). What is recommended. That is, it is preferable to use a thermoplastic resin having a melting point equal to or lower than the melting temperature of the solder for the insulating coating layer. In order to ensure that soldering can be performed in a short time and that the molten insulating coating layer does not burn out or shrink and interfere with the soldered parts, reliable conduction can be obtained within the range of the solder melting temperature. It can be said that those having a melting point in the low temperature range (“150 ° C. or lower” can be mentioned as an example of a guideline) are suitable.

Here, the selection of the insulating coating layer is not limited to the melting point alone, but also the thickness of the insulating coating layer covering the conductive yarn. For example, even if the melting point of the insulating coating layer is high (the temperature exceeds that when the standard is 150 ° C), if the coating thickness is thin, it will melt relatively easily during soldering. , Can be used as an insulating coating layer.

In the above description, 150 ° C. is given as an example of the guideline for the melting temperature of the solder, but the melting temperature varies depending on the resin selected for the insulating coating layer. For example, it should be 155 ° C for polyester, modified polyester, polyester-nylon, etc., 105 ° C for formal, 130 ° C for polyurethane, 180 ° C for polyesterimide, and so on.

The first electrode portion 31 and the second electrode portion 41 may be formed by mixing the elastic yarn with the conductive yarn. By mixing elastic threads, the elasticity of the first electrode portion 31 and the second electrode portion 41 can be improved. Further, the elastic yarn is preferably a non-conductive yarn. A polyurethane or rubber-based elastomer material may be used alone for the elastic yarn, or a covering yarn using polyurethane or rubber-based elastomer material for the "core" and nylon or polyester for the "cover" may be used. Can be adopted. By adopting such a covering yarn, it is possible to impart functions such as hydrophilicity, water repellency, corrosion resistance / corrosion resistance, and coloring. It is also useful for improving the feel and controlling elongation.

Here, from the viewpoint of accurately detecting the change in capacitance, the first electrode portion 31 has a resistance change rate (%) of the electric resistance value at 50% elongation with respect to the electric resistance value at 0% elongation. It is preferably configured to be 20% or less, and more preferably 10% or less. Further, it is more preferable to configure it so that it is 5% or less. Similarly, the second electrode portion 41 is also preferably configured such that the resistance change rate of the electric resistance value at 50% elongation with respect to the electric resistance value at 0% elongation is 20% or less, preferably 10% or less. It is more preferable to configure it so as to be. Further, it is more preferable to configure it so that it is 5% or less. Here, the resistance change rate (%) is [(electrical resistance value at 50% elongation rate)-(electrical resistance value at 0% elongation rate)] / (electrical resistance value at 0% elongation rate) × 100%. Is calculated as.

As described above, with respect to the first electrode portion 31 and the second electrode portion 41, in order to keep the resistance change rate (%) of the electric resistance value at 50% elongation to low with respect to the electric resistance value at 0% elongation, it is conductive. As the sex yarn, it is preferable to adopt a configuration in which the above-mentioned insulating coating layer is provided on the outer layer thereof. When the insulating coating layer is formed on the outer layer, the conductive yarn coated with the insulating coating layer is not particularly limited to the metal wire as described above. For example, a conductive thread formed from a conductive fiber such as the above-mentioned carbon fiber, a synthetic fiber, a natural fiber, or the like is used as a core, and a metal fiber is wound around the core, and a conductive thread, a synthetic fiber, a natural fiber, or the like is used as a core. As a result, an insulating coating layer may be provided on an outer layer such as a metal adherent fiber (plated yarn) having a metal component adhered to the core.

Further, with respect to the first electrode portion 31 and the second electrode portion 41, in order to suppress the resistance change rate (%) of the electric resistance value at the time of 50% extension with respect to the electric resistance value at the time of 0% extension, FIG. 2A is shown. A knitted fabric structure as shown in (b) can also be adopted. The knitted fabric structure shown in FIGS. 2 (a) and 2 (b) is a smooth knit (also referred to as double-sided knit or interlock), and it seems that two milling knits are overlapped to fill each other's uneven grooves. It is a knitted structure and is composed of a conductive yarn 10 and an elastic yarn 11. If the conductive thread 10 and the elastic thread 11 are included, it is optional to mix other kinds of threads. Explaining that the upper surface side of FIG. 2A is the knitted fabric surface side and the lower surface side is the knitted fabric back surface side, the conductive yarn 10 is entwined with the conductive yarn old loop 10a on the knitted fabric surface side and is the first loop. It forms P1 and shifts to the back side of the knitted fabric. Then, the second loop P2 is formed by being entwined with the conductive yarn old loop 10b on the back surface side of the knitted fabric, and thereafter, the third loop P3 is formed on the front surface side of the knitted fabric and the fourth loop P4 is formed on the back surface side of the knitted fabric. Repeat such things as doing. Therefore, the conductive yarn 10 is provided in a zigzag shape in the knitted fabric in the direction between the front and back sides.

On the other hand, the elastic yarn 11 is entwined with the elastic yarn old loop 11a on the back surface side of the knitted fabric to form the first loop R1 and shifts to the front surface side of the knitted fabric. Then, the second loop R2 is formed by being entwined with the elastic yarn old loop 11b on the knitted fabric surface side, and thereafter, the third loop R3 is formed on the knitted fabric back surface side and the fourth loop R4 is formed on the knitted fabric surface side. Repeat the formation. Therefore, the elastic yarn 11 is also provided in a zigzag shape in the knitted fabric in the direction between the front and back sides. As a result, in the knitted fabric, cross portions 13 of the conductive yarn 10 and the elastic yarn 11 are formed in an alternating arrangement for each loop.

Here, the elastic thread 11 has abundant elasticity, while the conductive thread 10 hardly expands and contracts. Therefore, when the knitted fabric structure is extended along the surface direction of the front and back surfaces (left-right direction in FIG. 2), the elastic yarn 11 intersects the conductive yarn 10 at the cross portion 13, and the front and back surfaces of the knitted fabric are knitted. The cross angle θ generated on the side is gradually expanded, and after a situation in which the angle becomes obtuse, only the elastic yarn 11 gradually stretches well. Next, a behavior occurs in which the conductive thread 10 is unwound from the loop to the cross portion 13 so as to be pulled by the elongation of the elastic thread 11. Further, when the extension is released, only the elastic thread 11 in the cross portion 13 generates a tightening force due to contraction, and the conductive thread 10 receives the tightening force and pushes the conductive thread 10 from the cross portion 13 into the loops on both outer sides thereof. .. The tightening force of the elastic yarn 11 at this time has an effect of retaining the zigzag-like arrangement of the conductive yarn 10 in the knitted fabric structure at the time of non-expansion.

In this way, the conductive thread 10 not only makes the loop smaller or larger by feeding or pushing it from the loop to the cross portion 13, but also expands and contracts together with the expansion and contraction of the elastic thread 11. The knitted fabric structure has elasticity as shown in FIG. 2 (b). As is clear from this explanation, since the conductive yarn 10 does not substantially expand and contract, the total length used in the course direction does not change, and the outer diameter thereof does not change. Not only that, in the conductive yarn 10, the loops arranged in the course direction do not come into contact with each other, and the loops do not get entangled or come into contact with each other between the plurality of courses, and the electric resistance does not change.

Further, the first electrode portion 31 is preferably configured so that the electric resistance value per unit length (1 cm) at 0% elongation is 50 Ω or less, and more preferably 10 Ω or less. .. Further, it is more preferable to configure it so as to be 5Ω or less. Similarly, the second electrode portion 41 is preferably configured so that the electric resistance value per unit length (1 cm) at 0% elongation is 50 Ω or less, and more preferably 10 Ω or less. preferable. Further, it is more preferable to configure it so as to be 5Ω or less.

Further, it is preferable that the first electrode portion 31 is configured to have stretch anisotropy. That is, it is preferable that the first electrode portion 31 is configured to have a characteristic that it easily extends in the longitudinal direction and does not easily extend in the lateral direction. In this way, when the dimensional change in the lateral direction of the first electrode portion 31 due to the extension is configured to be smaller than that in the longitudinal direction, when the first electrode portion 31 is extended by 50% in the longitudinal direction, It is preferable that the dimensional change rate in the lateral direction (the rate of change with respect to the dimensional change in the lateral direction when extended by 0%) is less than 5%. Such a configuration can be obtained, for example, by forming the first electrode portion 31 as a double knitted fabric. The double knitted fabric means a knitted fabric such as a milling cutter, a pearl cutter, and a smooth fabric. Since the double knitted fabric has a zigzag accordion structure formed in the thickness direction, the accordion structure effectively suppresses the dimensional change of the first electrode portion 31 in the lateral direction during expansion and contraction. Similarly, the second electrode portion 41 is preferably configured to have stretch anisotropy.

Synthetic fibers (for example, polyester fibers, nylon fibers, etc.), natural fibers, synthetic fibers and elastic yarns are mixed in the non-conductive yarns for forming the first non-conductive portion 32 and the second non-conductive portion 42. It is possible to use the materials that have been used. By mixing elastic yarns, the elasticity of the first non-conductive portion 32 and the second non-conductive portion 42 can be improved. For the elastic yarn, for example, a polyurethane or rubber-based elastomer material may be used alone, or a covering yarn using polyurethane or rubber-based elastomer material for the "core" and nylon or polyester for the "cover". Etc. can be adopted. By adopting such a covering yarn, it is possible to impart functions such as hydrophilicity, water repellency, corrosion resistance / corrosion resistance, and coloring. It is also useful for improving the feel and controlling elongation. Further, although it is possible to use a monofilament as the non-conductive yarn, a multifilament or a spun yarn, which is an aggregate of a plurality of single fibers, can be preferably used rather than a monofilament.

Further, the first non-conductive portion 32 and the second non-conductive portion 42 are preferably formed of non-conductive yarn having heat resistance to the melting temperature of the solder. Here, the heat resistance required for the non-conductive yarn forming the first non-conductive portion 32 and the second non-conductive portion 42 is ignited or melted by contact with the molten solder (or the soldering iron in a heated state). It means that it does not cause any loss and does not easily burn out. However, the degree of charring is within the permissible range (can be used for forming non-conductive parts). That is, as long as it has heat resistance to the extent that the shape remains even after soldering, the function is sufficient. In order to assist the action of preventing the molten solder from penetrating into the first non-conductive portion 32 and the second non-conductive portion 42, the knitted structure of the first non-conductive portion 32 and the second non-conductive portion 42 may be made into a dense structure. It is even more preferable to add measures. The heat resistance required for the first non-conductive portion 32 and the second non-conductive portion 42 is required at the contact position with the first electrode portion 31 and the second electrode portion 41. The entire band width direction of the first non-conductive portion 32 and the second non-conductive portion 42 does not necessarily have to have the same configuration. For example, regarding the first non-conductive portion 32, the course portion (non-conductive portion) in which only one course or several courses in contact with the first electrode portion 31 is provided with heat resistance and does not come into direct contact with the first electrode portion 31. It is also possible to knit by using a general knitting structure or a general material (those that do not have heat resistance to molten solder) for the central part in the band width direction. The same applies to the second non-conductive portion 42.

Specific examples of the heat-resistant non-conductive yarn preferable for forming the first non-conductive portion 32 and the second non-conductive portion 42 include various natural fibers such as cotton and wool, as well as glass fibers and ceramics. Fibers, carbon fibers, and various synthetic fibers (eg, aramid fiber, phenol fiber, PBO, polyarylate, polyimide, melamine, PPS, PEEK, PTFE, cellulose fiber (flame retardant processing), nylon (flame retardant processing)) , Acrylic fiber, etc.) and the like can be exemplified.

The first conductive layer 3 and the second conductive layer 4 configured as described above are integrally fixed to the dielectric layer 2 by heat pressing or the like. When the dielectric layer 2 is formed from a thermoplastic elastomer such as urethane rubber, the dielectric layer forming material melted by the heat during heat pressing is in the fabric of the first conductive layer 3 or the second conductive layer 4 (stitch or fiber). The first conductive layer 3 and the second conductive layer 4 are firmly fixed to the dielectric layer 2 because they enter the gaps between them and solidify. Here, the first electrode portion 31 included in the first conductive layer 3 and the second electrode portion 41 included in the second conductive layer 4 face each other via the dielectric layer 2 as shown in FIG. 1 (b). It is arranged and configured. In this way, by configuring the first electrode portion 31 and the second electrode portion 41 to face each other via the dielectric layer 2, the first conductive layer 3 and the second conductive layer are arranged so as to expand and contract the tensile sensor 1. It is possible to effectively suppress noise from entering the information of the capacitance change between the two and the above, and it is possible to improve the detection accuracy of the tensile sensor 1.

The operation of the tension sensor 1 having such a configuration will be described below. First, a voltage is applied to each of the first electrode portion 31 and the second electrode portion 41 included in the first conductive layer 3 and the second conductive layer 4, respectively. In this state, for example, when the tensile sensor 1 extends in the longitudinal direction, the distance between the first electrode portion 31 and the second electrode portion 41 becomes smaller, and the electrostatic charge between the first electrode portion 31 and the second electrode portion 41 becomes smaller. The capacity increases. Further, the area of the tensile sensor 1 is increased by the extension, and the capacitance between the first electrode portion 31 and the second electrode portion 41 is increased. Next, when the extension state is released and the tension sensor 1 contracts (the extension rate is 0%), the distance between the first electrode portion 31 and the second electrode portion 41 increases, and the area of the tension sensor 1 also decreases. Therefore, the capacitance between the first electrode portion 31 and the second electrode portion 41 becomes smaller. That is, when the tensile sensor 1 detects the deformation of the object to be detected, when the detected capacitance becomes large, it can be detected that the deformation has become large. More specifically, for example, when the tension sensor 1 is attached to the elbow portion or the knee portion of the jacket worn by a person, the tension sensor 1 is extended and detected due to the bending of the arm or leg. The value of the electric capacity changes greatly. By detecting the value of the capacitance at this time, the movement of the elbow or knee of the human body can be clearly detected. Further, for example, by attaching the tension sensor 1 to the chest or abdomen of the jacket worn by a person, or by attaching the tension sensor 1 so as to wind around the chest or waist, the wearer The tension sensor 1 expands and contracts based on the change in physique due to the breathing motion of the wearer. Information can be obtained.

As described above, the tensile sensor 1 in the present invention has a capacitance based on a change in the area of the tensile sensor 1 in addition to a change in the distance between the first electrode portion 31 and the second electrode portion 41 due to expansion and contraction. Since it is configured to be able to detect changes in the capacitance, it is possible to improve the detection sensitivity for changes in capacitance. Further, since the dielectric layer 2 having elasticity is provided between the first conductive layer 3 and the second conductive layer 4, the stretched state to the pre-stretched state (the stretch rate is 0%). It has the characteristic of being easy to return to, and has the effect that its elasticity is not easily impaired even if it is repeatedly expanded and contracted. Further, the presence of the dielectric layer 2 causes the conductive threads forming the first electrode portion 31 and the second electrode portion 41 to break, so that the first conductive layer 3 and the second conductive layer are broken. It is possible to effectively suppress the extension of 4 beyond the limit.

Further, the tensile sensor 1 according to the present invention is configured so that the resistance change rate of the first electrode portion 31 at the time of 50% extension is 20% or less, and similarly, the resistance change rate of the second electrode portion 41 at the time of 50% extension is Since the resistance change rate is configured to be 20% or less, it is possible to accurately capture the detected change in capacitance. Further, the electric resistance value per unit length (1 cm) of the first electrode portion 31 is configured to be 50 Ω or less, and similarly, the electric resistance per unit length (1 cm) of the second electrode portion 41. Since the value is configured to be 50Ω or less, it is possible to capture the detected change in capacitance more accurately.

Further, since the first electrode portion 31 and the second electrode portion 41 are configured to have a knitted fabric structure, the conductivity forming the first electrode portion 31 and the second electrode portion 41 by the extension of the tensile sensor 1. It is possible to have a structure in which the sex yarn is not easily broken.

Here, the first electrode portion 31 and the second electrode portion 41 configured to include the knitted fabric structure are, for example, milled, pearled, and smoother than in the case of being composed of a single knitted fabric such as a flat knitted fabric. When configured as a double knitted fabric such as knitting, it is possible to detect changes in capacitance with even higher accuracy. In the case of the double knitted fabric, since the zigzag accordion structure is formed in the thickness direction, the dimensional change in the lateral direction of the first electrode portion 31 and the second electrode portion 41 is effectively suppressed, and the first electrode accompanying the elongation is effectively suppressed. As a result of making it possible to make the area increase ratio of the portion 31 and the second electrode portion 41 substantially constant, it is possible to detect the change in capacitance with high accuracy.

Although the tension sensor 1 according to the embodiment of the present invention has been described above, the specific configuration of the tension sensor 1 is not limited to the above embodiment. For example, in the above embodiment, the first electrode portion 31 and the second electrode portion 41 have a linear shape extending along the longitudinal direction of the strip-shaped tension sensor 1 as shown in FIGS. 1 (a) and 1 (c). Although it is configured in a band shape, the specific form of the first electrode portion 31 and the second electrode portion 41 is not particularly limited, and for example, in a plan view, a wavy shape extending along the longitudinal direction of the tension sensor 1 or the like. It can be configured in various forms such as a zigzag shape.

Further, in the above embodiment, the first conductive layer 3 is configured to include the first non-conductive portion 32, but the first non-conductive portion 32 is omitted and only the first electrode portion 31 is used. 1 Conductive layer 3 may be configured. Similarly, the second conductive layer 4 may be formed only by the second electrode portion 41.

Further, a coating layer may be provided to cover the surface of the exposed surface (the surface on the side not in contact with the dielectric layer 2) of the first conductive layer 3 and the second conductive layer 4. By providing such a coating layer, the first electrode portion 31 and the second electrode portion 41 can be protected, and the durability of the tensile sensor 1 can be improved. The coating layer may be provided on only one of the first conductive layer 3 side or the second conductive layer 4 side. As the material for forming the coating layer, for example, the material for forming the dielectric layer 2 described above, the stretchable cloth, or the like can be used.

Further, in the above embodiment, the first conductive layer 3 and the second conductive layer 4 are provided with a single first electrode portion 31 and a plurality of second electrode portions 41, respectively, as shown in FIG. Although it is configured, the number of the first electrode portion 31 and the second electrode portion 41 is not particularly limited, and for example, as shown in FIGS. 3A, 3B, and 3C, the dielectric layer 2 is used. The tensile sensor 1 may be configured by disposing a plurality of first electrode portions 31 and a plurality of second electrode portions 41 on both sides thereof. In the configuration shown in FIG. 3, the first electrode portions 31 are arranged so as to be parallel to each other at a predetermined interval, and the second electrode portions 41 are also arranged to be parallel to each other at a predetermined interval. It is arranged so as to be. The first non-conductive portion 32 is arranged between the first electrode portions 31, and the second non-conductive portion 42 is arranged between the second electrode portions 41. Further, when such a configuration is adopted, it is preferable that the first electrode portion 31 and the second electrode portion 41 are arranged at positions facing each other via the dielectric layer 2. 3A is a schematic configuration plan view of the tension sensor 1, and FIG. 3B is a schematic configuration sectional view showing a cross section of A'-A'in FIG. 3A. Further, FIG. 3C is a schematic back view of the configuration.

Further, in the configuration shown in FIG. 3, in order to configure the aggregate of the plurality of first electrode portions 31 as one electrode, one end of each first electrode portion 31 is short-circuited and each first electrode portion 31 is short-circuited. The other end portions of one electrode portion 31 may be short-circuited to each other, and similarly, in order to configure an aggregate of a plurality of second electrode portions 41 as one electrode, each second electrode portion 41 may be configured. The ends on one side may be short-circuited, and the ends on the other side of each first electrode portion 31 may be short-circuited.

Further, in the configuration shown in FIG. 3, each combination of the first electrode portion 31 and the second electrode portions 41 arranged opposite to each other via the dielectric layer 2 (first electrode portion 31a and second electrode portion 41a). , The combination of the first electrode portion 31b and the second electrode portion 41b, the combination of the first electrode portion 31c and the second electrode portion 41c) may be configured as an independent capacitor. When such a configuration is adopted, the tension sensor 1 can not only detect the tension in the longitudinal direction but also the twist about the longitudinal direction. Specifically, when the tensile sensor 1 is twisted about its longitudinal direction, the central portion of the tensile sensor 1 is deformed more than the side edge portion, and is therefore arranged in the center. The value of the capacitance change detected by the capacitor composed of the first electrode portion 31b and the second electrode portion 41b, and the first electrode portion 31a (31c) and the second electrode portion 41a (1) arranged on the side edge portion. There is a difference from the value of the capacitance change detected by the capacitor configured with 41c). By detecting this difference, it becomes possible to determine whether or not a twist is applied to the tension sensor 1.

Further, in the above embodiment, the widths (dimensions in the direction perpendicular to the longitudinal direction) of the first electrode portion 31 and the second electrode portion 41 are configured to have the same dimensions, but such a configuration. It is not particularly limited to. For example, as shown in the schematic structural cross-sectional view of FIG. 4, the area of the second electrode portion 41 in a plan view is set to be larger than the width of the first electrode portion 31 by making the width of the second electrode portion 41 larger than the width of the first electrode portion 31. It may be configured to have an area larger than the area of the 1 electrode portion 31, and the second electrode portion 41 may be arranged at a position facing the first electrode portion 31 via the dielectric layer 2. That is, when the first electrode portion 31 is virtually projected onto the second conductive layer 4, the first electrode portion 31 is arranged in the second electrode portion 41 forming region. And the second electrode portion 41 may be configured. By adopting such a configuration, for example, when the tensile sensor 1 is attached to clothes or the like so that the second conductive layer 4 is on the human body side, the second electrode portion 41 exerts the role of a shield. Therefore, it is possible to effectively suppress the occurrence of capacitive coupling between the human body and the first electrode portion 31. Further, in the configuration as shown in FIG. 1, the first conductive layer 3 and the second conductive layer 4 are arranged so that the first electrode portion 31 and the second electrode portion 41 are arranged so as to face each other via the dielectric layer 2. However, as shown in FIG. 4, when the area of the second electrode portion 41 is configured to have a larger area than the area of the first electrode portion 31, the dielectric layer 2 is used. It is not necessary to strictly align the first conductive layer 3 and the second conductive layer 4 with respect to the above, and the tensile sensor 1 can be efficiently manufactured.

Further, in the case of adopting a configuration in which the first conductive layer 3 includes a plurality of first electrode portions 31, as shown in the schematic configuration sectional view of FIG. 5, a region in which the plurality of first electrode portions 31 are arranged. The second electrode portion 41 is configured to have an area larger than the area, and the second electrode portion 41 is located at a position facing the region where the plurality of first electrode portions 31 are arranged via the dielectric layer 2. It may be configured to be arranged. That is, when all of the plurality of first electrode portions 31 are virtually projected onto the second conductive layer 4, all of the plurality of first electrode portions 31 overlap with the single second electrode portion 41. , Each of the first electrode portion 31 and the second electrode portion 41 may be configured. By adopting such a configuration, similarly to the above, for example, when the tensile sensor 1 is attached to clothes or the like so that the second conductive layer 4 is on the human body side, the second electrode portion 41 shields. It is possible to effectively suppress the occurrence of capacitive coupling between the human body and each of the first electrode portions 31. Further, in the configuration as shown in FIG. 3, the first conductive layer 3 and the second conductive layer 3 are arranged so that the first electrode portion 31 and the second electrode portion 41 face each other with the dielectric layer 2 interposed therebetween. It is necessary to perform positioning with the layer 4 with high accuracy, but by configuring the area of the second electrode portion 41 in a plan view to be larger than the area of the region where the plurality of first electrode portions 31 are arranged. It is no longer necessary to strictly align the first conductive layer 3 and the second conductive layer 4 with respect to the dielectric layer 2, and the tensile sensor 1 can be efficiently manufactured.

Further, in the above embodiment, both the first conductive layer 3 and the second conductive layer 4 are configured as a knitted or woven fabric using conductive yarn and non-conductive yarn. The configuration is not particularly limited, and for example, as shown in the schematic structural cross-sectional views of FIGS. 6A and 6B, the second electrode portion 41 is formed on one surface of the elastomer substrate 5 as the second conductive layer 4. You may adopt the structure formed by printing. Here, FIG. 6A shows a structure in which the first electrode portion 31 and the second electrode portion 41 have a single configuration, and the width of the second electrode portion 41 is formed to have the same dimensions as the width of the first electrode portion 31. FIG. 6B shows a structure in which a single second electrode portion 41 is formed so as to have an area larger than the area of the region in which the plurality of first electrode portions 31 are arranged.

As the material of the elastomer base material 5, the above-mentioned material forming the dielectric layer 2 can be used. Further, as the conductive material constituting the second electrode portion 41 to be printed and formed, various carbon materials such as graphite, carbon black, acetylene black, ketjen black, carbon whisker, carbon fiber, carbon nanotube, and carbon microcoil are used. , Various metal materials such as gold, platinum, palladium, ruthenium, silver, iron, cobalt, nickel, copper and titanium, and conductive polymer materials. A conductive slurry prepared by kneading powders of these materials with an organic solvent or a resin binder may be applied and dried on an elastomer base material 5, and may be formed by a plasma CVD method, an ion sputter coating method, or vacuum vapor deposition. It may be formed by a method, screen printing, or the like. Since the second electrode portion 41 to be printed is preferably flexible enough to smoothly follow the expansion and contraction of the tensile sensor 1, the above-mentioned conductive material and the resin binder are kneaded into a high height. It is more preferable to form using a molecular material or a conductive polymer material.

Further, in the above embodiment, the dielectric layer 2 is formed of a thermoplastic elastomer such as urethane rubber, and the first conductive layer is formed via the thermoplastic elastomer (dielectric layer forming material) melted by the heat during heat pressing. Although the configuration in which the 3 and the second conductive layer 4 are fixed to the dielectric layer 2 has been described, the configuration is not particularly limited to such a configuration, and for example, as shown in the cross-sectional view of FIG. 7, via the adhesive layer 6. Then, the first conductive layer 3 and the second conductive layer 4 may be bonded to the dielectric layer 2 to form the tensile sensor 1. Here, as the adhesive for forming the adhesive layer 6, a general adhesive such as an acrylic type or an epoxy type can be used.

Further, in the above embodiment, the thermoplastic elastomer is exemplified as the material constituting the dielectric layer 2, but the material is not particularly limited to such a material, and for example, the dielectric layer 2 has elasticity. It may be configured to include a cloth (fabric). When the dielectric layer 2 is configured to include the cloth, as shown in FIG. 7, the first conductive layer 3 and the second conductive layer 4 are arranged and fixed on both sides of the cloth via the adhesive layer, respectively. The tensile sensor 1 can be formed. Here, examples of the stretchable fabric include elastic fabrics for waistbands, supporters, T-shirts, and the like. The fabric is preferably configured to have stretch anisotropy. That is, it is preferable that the dielectric layer 2 configured to include the cloth is configured to have a property of being easily stretched in the longitudinal direction and not easily stretched in the lateral direction.

The inventors of the present invention have prepared samples (sensor sample A and sensor sample B) of the tensile sensor 1 according to the present invention and evaluated their performance when they were stretched, and will be described below. The sensor sample A employs an enamel-coated metal wire as a conductive thread to form a first electrode portion 31 and a second electrode portion 41, and the sensor sample B uses a silver-plated thread as a conductive thread. It is adopted as a sex thread to form a first electrode portion 31 and a second electrode portion 41.

First, the sensor sample A will be described below. This sensor sample A has a structure as shown in FIG. That is, the first conductive layer 3 in which the four first electrode portions 31 are arranged to be parallel to each other and the second conductive layer 4 in which the four second electrode portions 41 are arranged to be parallel to each other. And a dielectric layer 2 interposed between the first conductive layer 3 and the second conductive layer 4. 8 (a) is a schematic structural plan view of the sensor sample A, and FIG. 8 (b) is a schematic structural sectional view showing an A "-A" cross section of FIG. 8 (a). Further, FIG. 8C is a schematic back view of the configuration.

Each of the first conductive layer 3 and the second conductive layer 4 is configured such that the structure thereof comprises a milling knitting structure. More specifically, it is formed by being knitted in a band shape with 32 courses consisting of 32 yarn feeding ports as one unit (four first electrode portions 31 (second electrode portions 41) in a knitted structure consisting of 32 courses. ) Is included). After knitting, the knitted fabric is formed with the first conductive layer 3 and the second conductive layer 4 according to the sample 1 through a heat setting process usually performed in the manufacturing stage. Here, Table 1 shows the details of the yarns supplied from each of the 32 yarn feeders.

上記表１に示すように、給糸口番号：５～８、１２～１５、１９～２２、２６～２９の各組からは導電性糸が供給されており、また、これら導電性糸が供給される給糸口番号の各組同士の間に、非導電性糸が供給される給仕口番号：９～１１、１６～１８、２３～２５の各組を備えるようにして第１導電層３（第２導電層４）が編成されているため、導電性糸を含む互いに独立した４本の帯状（ライン状）の第１電極部３１（第２電極部４１）が、互いに平行な状態を維持して帯状の第１導電層３（第２導電層４）が編成される。なお、形成された第１導電層３及び第２導電層４は、長さが７５ｍｍ、幅が１０ｍｍ、厚みが０．８５ｍｍの短冊状である（１本の第１電極部３１（第２電極部４１）の幅は、１．２ｍｍとなるように形成されている）。また、第１導電層３においては、複数の第１電極部３１の集合体を一つの電極として構成するために、各第１電極部３１の一方側の端部同士を短絡させると共に、各第１電極部３１の他方側の端部同士を短絡させている。第２導電層４についても同様である。

As shown in Table 1 above, conductive yarns are supplied from each set of yarn feeder numbers: 5 to 8, 12 to 15, 19 to 22, and 26 to 29, and these conductive yarns are supplied. The first conductive layer 3 (the first conductive layer 3) is provided with each set of the feeder numbers: 9 to 11, 16 to 18, and 23 to 25 to which the non-conductive yarn is supplied between the sets of the yarn supply port numbers. Since the two conductive layers 4) are knitted, the four independent strip-shaped (line-shaped) first electrode portions 31 (second electrode portions 41) including the conductive threads maintain a state parallel to each other. The band-shaped first conductive layer 3 (second conductive layer 4) is knitted. The formed first conductive layer 3 and second conductive layer 4 are strip-shaped with a length of 75 mm, a width of 10 mm, and a thickness of 0.85 mm (one first electrode portion 31 (second electrode)). The width of the portion 41) is formed to be 1.2 mm). Further, in the first conductive layer 3, in order to form an aggregate of a plurality of first electrode portions 31 as one electrode, one end of each first electrode portion 31 is short-circuited and each first electrode portion 31 is short-circuited. 1 The other end of the electrode portion 31 is short-circuited. The same applies to the second conductive layer 4.

Further, as the dielectric layer 2, Esmer URS # 10 (thermoplastic elastomer film, thickness: 100 μm) manufactured by Nippon Matai Co., Ltd. is used, and the above-mentioned first conductive layer 3 is used on both surfaces of the film (dielectric layer 2). And the second conductive layer 4 were bonded together at a temperature of 180 ° C. to form a sensor sample A.

The created sensor sample A is sandwiched between a stand with a chuck, and the stand is placed while applying a voltage to each of the first conductive layer 3 (first electrode portion 31) and the second conductive layer 4 (second electrode portion 41). It was moved and stretched, and the change in capacitance associated with the stretching was measured. The measurement of the capacitance value due to the elongation was performed twice in total.

Table 2 and FIG. 9 show the relationship between the elongation rate of the sensor sample A related to the tensile sensor 1 and the detected capacitance value. Here, the value of the capacitance shown in Table 2 is an average value of the measurement results performed twice. From the results of Table 2 and FIG. 9, it can be seen that the sensor sample A can detect the change in capacitance with high accuracy and high sensitivity with respect to expansion and contraction. In particular, since it has the property that the value of capacitance linearly increases with its elongation, it can be seen that the deformed state and tensile force of the object to be detected can be detected and measured with extremely high accuracy. ..

Next, the sensor sample B will be described. In this sensor sample B, the first conductive layer 3 is composed of only the first electrode portion 31, and the second conductive layer 4 is also composed of only the second electrode portion 41. Each of the first electrode portion 31 and the second electrode portion 41 is formed in the same manner, and is formed by milling a silver-plated yarn. The first conductive layer 3 (first electrode portion 31) and the second conductive layer 4 (second electrode portion 41) are formed in a strip shape having a length of 100 mm, a width of 10 mm, and a thickness of 0.85 mm. There is.

Further, as the dielectric layer 2, a bare milling cloth (thickness: 0.5 mm) formed of non-conductive yarn is used, and the above-mentioned first conductive layer 3 and the first conductive layer 3 and the above-mentioned first conductive layer 3 and the above-mentioned first conductive layer 3 on both sides of the cloth (dielectric layer 2). 2 The conductive layer 4 was adhered to form a sensor sample B.

The created strip-shaped sensor sample B is sandwiched between stands with chucks, and voltage is applied to each of the first conductive layer 3 (first electrode portion 31) and the second conductive layer 4 (second electrode portion 41). , The stand was moved and stretched, and the change in capacitance accompanying the stretching was measured. The measurement of the capacitance value due to the elongation was performed twice in total.

The relationship between the elongation rate of the sensor sample B and the detected capacitance value is shown in Table 3 and FIG. Here, the value of the capacitance shown in Table 3 is an average value of the measurement results performed twice. From the results of Table 3 and FIG. 10, it can be seen that the sensor sample B, like the sensor sample A, can detect the change in capacitance with high accuracy and high sensitivity with respect to expansion and contraction. Further, since this sensor sample B also has a characteristic that the value of the capacitance linearly increases with its elongation, the deformed state and the tensile force of the object to be detected are detected and measured with extremely high accuracy. You can see that you can.

Further, the inventors prepared an electrode portion sample A and an electrode portion sample B in order to confirm the resistance change rate accompanying the elongation of the first electrode portion 31 (second electrode portion 41), and stretched each of the samples. The accompanying resistance change rate was measured. Hereinafter, this measurement result will be described.

First, as the electrode portion sample A to be subjected to the measurement test of the resistance change rate due to elongation, a knitted fabric knitted with the threads shown in Table 1 (knitted fabric corresponding to the above sensor sample A) was prepared, and the knitted fabric was prepared. One of the four electrode portions (first electrode portion 31 or second electrode portion 41) provided in the above was selected, and the rate of change in resistance with elongation was measured. The electrode portion sample A has a form of a length of 100 mm, a width of 1.2 mm, and a thickness of 0.85 mm. The measurement method is to sandwich the sample with a stand with a chuck, move the stand to extend it to a predetermined elongation rate, measure the electrical resistance value between both ends of the sample, and calculate the resistance change rate from the measured electrical resistance value. bottom. The electric resistance value was measured four times in total.

Table 4 shows the relationship between the elongation rate of the electrode sample 1 and the measured electrical resistance value. Table 5 shows the relationship between the elongation rate of the electrode sample A and the resistance change rate. Here, the resistance change rate is calculated as [(electric resistance value at each elongation rate)-(electric resistance value at 0% elongation rate)] / (electric resistance value at 0% elongation rate) × 100%. There is.

From the results in Table 4, it can be seen that the electrode portion sample A has a low electrical resistance value of about 0.05 Ω per unit length (1 cm) at 0% elongation. Further, as shown in Table 5, in the range of 100% elongation or less, the resistance change rate (%) with respect to the electric resistance value at 0% elongation is approximately 0 (zero)%, and with elongation. , It can be seen that the electric resistance value does not change. From this, when the first electrode portion 31 (second electrode portion 41) is configured by using the conductive thread having the insulating coating layer on the surface, the resistance change in impedance is extremely small, and the change in capacitance is accurate. It turns out that it can be detected. Here, as for the results of Tables 4 and 5, a knitted fabric (knitted fabric corresponding to the sensor sample A) knitted by the thread usage shown in Table 1 is prepared as described above, and the four knitted fabrics are provided. One of the electrode portions (first electrode portion 31 or second electrode portion 41) was selected as the electrode portion sample A and the resistance change rate was measured. In the case where one end of each electrode is short-circuited and the other end of each electrode is short-circuited in order to configure the body as one electrode, the electricity shown in Table 4 is used. The value of the resistance value is 1/4, and the electric resistance value per unit length (1 cm) at 0% elongation is about 0.01Ω. Further, the rate of change in resistance with elongation is the same as the result shown in Table 5 regardless of whether the resistance is four or one.

Next, as the electrode portion sample B to be subjected to the resistance change rate confirmation test, the same one as the first conductive layer 3 of the sensor sample B described above is adopted, and the resistance of the electrode portion sample B at the time of elongation is adopted. The rate of change was measured. The measurement method is to sandwich the sample with a stand with a chuck, move the stand to extend it to a predetermined elongation rate, measure the electrical resistance value between both ends of the sample, and calculate the resistance change rate from the measured electrical resistance value. bottom. The electric resistance value was measured four times in total.

Table 6 shows the relationship between the elongation rate of the electrode portion sample B and the measured electrical resistance value. Table 7 shows the relationship between the elongation rate of the electrode sample B and the resistance change rate. Here, the resistance change rate is calculated as [(electric resistance value at each elongation rate)-(electric resistance value at 0% elongation rate)] / (electric resistance value at 0% elongation rate) × 100%. There is.

From the results in Table 6, it can be seen that the electrode portion sample B has a low electrical resistance value of 0.3 Ω or less per unit length (1 cm) at 0% elongation. Further, as shown in Table 7, the resistance change rate (%) with respect to the electric resistance value at 0% elongation is 20% or less in the range of 60% elongation or less, and the electric resistance value due to elongation is 20% or less. It can be seen that the change is small. From this, even when the first electrode portion 31 (second electrode portion 41) is configured by using the plated yarn, the change in resistance in impedance is small and the change in capacitance can be accurately detected. I understand.

Further, from the results of Tables 6 and 7, the electrode portion sample B has an increased electrical resistance value between 0% elongation (initial state) and 10% elongation, and then between 10% elongation and 60% elongation. Then, it can be seen that the electric resistance value is substantially constant. The reason why the electric resistance value increases between 0% elongation (initial state) and 10% elongation is the contact state between the silver-plated yarns at the time of 0% elongation (contact state between the non-stretched silver-plated yarns). It is conceivable that the contact state between the silver-plated yarns will change significantly when even a small amount of tensile force is applied. On the other hand, in the electrode portion sample A having the insulating coating layer, unlike the electrode portion sample B, an increase in the electric resistance value immediately after the tensile force is applied is not observed, so that the first electrode portion 31 (second electrode) is not observed. It can be seen that it is more preferable to provide an insulating coating layer on the surface of the conductive yarn constituting the portion 41).

1 Tension sensor 2 Dielectric layer 3 1st conductive layer 31 1st electrode part 32 1st non-conductive part 4 2nd conductive layer 41 2nd electrode part 42 2nd non-conductive part 5 Elastomer base material 6 Adhesive layer

Claims (10)

A dielectric layer that is elastic and contains a thermoplastic elastomer,
A first conductive layer and a second conductive layer having elasticity provided on one surface and the other surface of the dielectric layer are provided.
The first conductive layer includes a band-shaped first electrode portion formed of a conductive thread.
The resistance change rate of the first electrode portion when extended by 50% is 20% or less.
A strip-shaped tensile sensor capable of detecting a change in capacitance between the first conductive layer and the second conductive layer due to expansion and contraction. The tensile sensor according to claim 1, wherein the first electrode portion has an electric resistance value of 50 Ω or less per unit length (1 cm) at 0% elongation. The second conductive layer includes a band-shaped second electrode portion formed of a conductive thread.
The tensile sensor according to claim 1 or 2, wherein the second electrode portion is arranged at a position facing the first electrode portion via the dielectric layer. The first conductive layer includes a plurality of the first electrode portions, and the first electrode portions are arranged in parallel with each other at predetermined intervals.
The second conductive layer includes a plurality of second electrode portions, and the second electrode portions are arranged in parallel with each other at predetermined intervals.
The tensile sensor according to claim 1 or 2 , wherein each of the first electrode portions and the second electrode portions are arranged so as to face each other with the dielectric layer interposed therebetween. The second conductive layer includes a second electrode portion having an area larger than the area of the first electrode portion.
The tensile sensor according to any one of claims 1 to 4, wherein the second electrode portion is arranged at a position facing the first electrode portion via the dielectric layer. The first conductive layer includes a plurality of the first electrode portions, and the first electrode portions are arranged in parallel with each other at predetermined intervals.
The second conductive layer includes a second electrode portion having an area larger than the area of the region where the plurality of first electrode portions are arranged.
The tensile sensor according to any one of claims 1 to 3, wherein the second electrode portion is arranged at a position facing the region where the plurality of first electrode portions are arranged via the dielectric layer. The tension sensor according to any one of claims 1 to 6, wherein the conductive yarn is covered with an insulating coating layer. The insulating coating layer includes polyurethane, polyvinyl chloride, polypropylene, polyethylene, nylon, polyester, polyethylene terephthalate, polybutylene terephthalate, polyvinylidene sulfide, polyether ether ketone, PFA, PVDF, ETFE and other fluororesins, polystyrene, polycarbonate, etc. The tensile sensor according to claim 7, wherein the tensile sensor is formed from at least one selected from the group of polysulfone, polyether sulfone, formal (polyvinyl formal), and butyral (polyvinyl butyral). The tensile sensor according to any one of claims 1 to 8, wherein the first electrode portion has stretch anisotropy. The tensile sensor according to claim 9, wherein the first electrode portion has a dimensional change rate of less than 5% in the lateral direction when extended by 50% in the longitudinal direction.

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