JP7365653B1 - Rubber sensor, sensing rubber composition constituting it, and tire - Google Patents

Abstract

The present invention provides a rubber sensor that does not require electricity and can reduce shape restrictions, a sensing rubber composition including the same, and a tire. [Solution] A rubber sensor 10 for detecting a mechanical load includes a rubber material in which a carrier capable of supporting a deliquescent substance is distributed and a flow path is formed, and the deliquescent substance is dissolved in the flow path. A sensing rubber composition 11 that holds an electrolyte solution, and a plurality of electrodes 12 and 13 that are in contact with the sensing rubber composition 11 and not in contact with each other, and one electrode 12 and the other electrodes 12 have different ionization tendencies. The potential difference between the sensing rubber composition 11 and the electrode 13 changes as a mechanical load is applied to the sensing rubber composition 11. [Selection diagram] Figure 1

Description

The present invention relates to a rubber sensor capable of detecting a mechanical load, a sensing rubber composition constituting the sensor, and a tire.

A sensor using a strain gauge or a sensor using a piezoelectric element is used to detect a dynamic load (see Patent Documents 1 and 2). A strain gauge detects strain occurring in an object to be detected as a change in electrical resistance, and generally, to detect strain, it is necessary to keep the strain gauge in an energized state.
On the other hand, a piezoelectric element that detects a mechanical load using a piezoelectric effect does not require an external voltage to be applied to the piezoelectric element.

Japanese Patent Application Publication No. 2018-21796 JP2021-186238A

However, the piezoelectric element has a problem in that its shape is limited in order to efficiently generate electricity and stably detect a mechanical load. Furthermore, it is assumed that both the piezoelectric element and the strain gauge are used in the manufactured shape, and depending on the conditions at the site of use, for example, the piezoelectric element and the strain gauge cannot be used by cutting them in half.
The present invention has been made in view of the above circumstances, and aims to provide a rubber sensor that does not require electricity and has reduced shape restrictions, a sensing rubber composition constituting the same, and a tire.

A rubber sensor according to a first invention that meets the above object is a rubber sensor that detects a mechanical load, in which a carrier capable of supporting a deliquescent substance and holding the deliquescent substance is distributed to form a flow path. A sensing rubber composition having a rubber material and holding an electrolyte solution in which the deliquescent substance is dissolved in the flow path, and a plurality of electrodes that are in contact with the sensing rubber composition and are not in contact with each other, The potential difference between one of the electrodes and another electrode having a different ionization tendency changes as a mechanical load is applied to the sensing rubber composition.

A sensing rubber composition according to a second invention in accordance with the above object is a sensing rubber composition that constitutes a rubber sensor for detecting a mechanical load together with a plurality of electrodes attached in contact with each other, and the sensing rubber composition comprises a deliquescent substance. It has a rubber material in which a carrier capable of supporting and holding the deliquescent substance is distributed and a flow path is formed, an electrolyte solution in which the deliquescent substance is dissolved is held in the flow path, and a mechanical load is not applied. and changes the potential difference between one of the electrodes and another electrode having a different ionization tendency.

A tire according to a third aspect of the invention in accordance with the above object is a tire having a rubber sensor for detecting a mechanical load, wherein the rubber sensor is capable of supporting a deliquescent substance and has a carrier holding the deliquescent substance distributed therein. , a sensing rubber composition having a rubber material in which a flow path is formed and holding an electrolyte solution in which the deliquescent substance is dissolved in the flow path; The sensing rubber composition is provided with a plurality of electrodes, and the potential difference between one of the electrodes and another electrode having a different ionization tendency from that electrode changes as a mechanical load is applied to the sensing rubber composition.

A tire according to a fourth aspect of the invention in accordance with the above object is a tire having a sensing rubber composition constituting a rubber sensor for detecting a mechanical load together with a plurality of electrodes attached in contact with each other, wherein the sensing rubber composition The object has a rubber material capable of supporting a deliquescent substance, in which a carrier holding the deliquescent substance is distributed, and a channel is formed, and an electrolyte solution in which the deliquescent substance is dissolved is held in the channel. However, a mechanical load is applied to change the potential difference between one of the electrodes and another electrode having a different ionization tendency from that electrode.

The rubber sensor according to the first invention includes a rubber material in which a carrier capable of supporting a deliquescent substance is distributed and a flow path is formed, and the sensing rubber retains an electrolyte solution in which the deliquescent substance is dissolved in the flow path. a composition, and a plurality of electrodes that are in contact with the sensing rubber composition and are not in contact with each other, and a potential difference between one electrode and another electrode having a different ionization tendency from the one electrode causes the sensing rubber composition to mechanically Since it changes when a load is applied to it, there is no need for energization and restrictions on shape can be reduced.

The sensing rubber composition according to the second invention is a composition that constitutes a rubber sensor for detecting mechanical loads together with a plurality of electrodes attached in contact with each other, in which a carrier capable of supporting a deliquescent substance is distributed. The electrode has a rubber material in which a flow path is formed, holds an electrolyte solution in which a deliquescent substance is dissolved in the flow path, and when a mechanical load is applied, the ionization tendency is different from that of the first electrode. Since the potential difference with other electrodes is changed, the rubber sensor does not need to be energized and can be made with fewer restrictions on shape.

Since the tire according to the third invention includes the rubber sensor according to the first invention, it is equipped with a rubber sensor that does not require electricity and can reduce restrictions on shape.
Since the tire according to the fourth invention includes the sensing rubber composition according to the second invention, the sensing rubber composition can form a rubber sensor that can reduce restrictions on shape and does not require energization.

FIG. 1 is an explanatory diagram of a rubber sensor according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of a first sample of a rubber sensor used in a mechanical load experiment. It is an explanatory view showing measurement results of a mechanical load experiment. It is an explanatory view showing measurement results of a mechanical load experiment. It is an explanatory view showing measurement results of a mechanical load experiment. It is an explanatory view showing measurement results of a mechanical load experiment. It is an explanatory view showing measurement results of a mechanical load experiment. It is an explanatory view showing measurement results of a mechanical load experiment. FIG. 6 is an explanatory diagram of a second sample of the rubber sensor used in the heat application experiment. FIG. 7 is an explanatory diagram showing measurement results of a heat application experiment on a second sample. FIG. 7 is an explanatory diagram showing measurement results of a heat application experiment on a third sample. FIG. 7 is an explanatory diagram showing measurement results of a heat application experiment on a fourth sample. FIG. 7 is an explanatory diagram of a fifth sample of the rubber sensor used in the voltage application experiment. FIG. 3 is an explanatory diagram showing measurement results of a voltage application experiment. FIG. 7 is an explanatory diagram showing the voltage application position for the fifth sample in a voltage application experiment. FIG. 3 is an explanatory diagram showing measurement results of a voltage application experiment. (A) and (B) are explanatory diagrams of a rubber sensor according to a modified example.

Next, embodiments embodying the present invention will be described with reference to the attached drawings to provide an understanding of the present invention.
As shown in FIG. 1, a rubber sensor 10 according to an embodiment of the present invention includes a rubber material in which a carrier capable of supporting a deliquescent substance is distributed and a flow path is formed, and a deliquescent material is formed in the flow path. A sensor for detecting a mechanical load, comprising a sensing rubber composition 11 holding an electrolyte solution in which a substance is dissolved, and a plurality of electrodes 12 and 13 that are in contact with the sensing rubber composition 11 and are not in contact with each other. be. This will be explained in detail below.

The rubber material included in the sensing rubber composition 11 is not particularly limited, and examples of the rubber material include natural rubber, styrene-butadiene rubber, chloroprene rubber, acrylonitrile rubber, butyl rubber, ethylene propylene rubber, ethylene propylene diene rubber, urethane rubber, and silicone. Rubber, fluororubber, chlorosulfonated polyethylene rubber, acrylic rubber, isoprene rubber or epichlorohydrin rubber can be selected.

In addition, porous materials or hollow materials can be used as the carrier, such as zeolite, diatomaceous earth, shirasu balloons, carbon black, carbon nanotubes, graphene, silica gel, montmorillonite, kaolinite, pumice, shale, mesoporous silica, porous One or more materials selected from the group of polymer beads, graphite, cellulose nanofibers, cork, and gamma alumina can be employed.

The carrier distributed in the rubber material is a mixture of an uncured (unvulcanized) elastomer (hereinafter simply referred to as "elastomer") that becomes the rubber material when it hardens, with a deliquescent substance supported on it. It is. The carrier may be any carrier as long as it can be distributed evenly in the uncured elastomer by the mixing treatment, and the size and shape of the carrier are not limited. For example, a particulate carrier having an average particle diameter (measured by laser diffraction/scattering method) of 10 nm or more and 100 μm or less can be used.

In this embodiment, the deliquescent substances include calcium chloride, magnesium chloride, potassium pyrophosphate, magnesium perchlorate, calcium nitrate, magnesium nitrate, magnesium acetate, potassium acetate, potassium carbonate, sodium hydroxide, sodium nitrate, and iodide. Sodium, phosphoric acid, chromium oxide, iron nitrate, cobalt chloride, nickel chloride, copper chloride, zinc chloride, zinc iodide, tin chloride, selenic acid, ammonium acetate, lithium iodide, ammonium fluoride, benzenesulfonic acid, urea and One type of substance or multiple types of substances selected from the group of potassium thiocyanates are employed.

The rubber material has channels formed evenly on its surface and inside. In this embodiment, the flow path is formed to extend three-dimensionally throughout the rubber material.
The channels are formed in a network throughout the rubber material during the process of curing the uncured elastomer to obtain the rubber material. In addition, by mixing a liquid (preferably a nonpolar solvent such as benzene or acetone) with a carrier and a liquid having a lower evaporation temperature than the deliquescent substance into the elastomer and evaporating the liquid when the elastomer is cured, it can be applied to the rubber material. Formation of a flow path can be promoted.

The formation of channels in the rubber material can also be promoted by adjusting the mixing conditions when mixing the elastomer and carrier. Here, promoting the formation of a flow path means connecting one flow path to another flow path, widening the flow path (increasing the diameter, etc.) with respect to the flow path formed during the curing process of the elastomer. , lengthening).
In this embodiment, when the sensing rubber composition 11 is divided into cubes each having a side length of 2 mm (preferably 1 mm, more preferably 500 μm), the flow channels are set so that the flow channels are present in 90% or more of the cubes. are uniformly distributed in the sensing rubber composition 11.

The electrolyte solution held in the flow path of the rubber material is a solution in which a deliquescent substance is dissolved in a solution containing water (water, ethanol water, etc.). The water contained in the electrolyte solution is brought about by mixing a carrier carrying a deliquescent substance dissolved in a solution into an elastomer, as well as by mixing the deliquescent substance distributed in the rubber material into a carrier. It is also produced by taking moisture (water vapor) in the air through channels formed in the rubber material and dissolving it.

Note that the deliquescent substance may be supported on a carrier in an undissolved state and mixed with the elastomer. In that case, the water contained in the electrolyte solution will be absorbed by the air from the deliquescent substance distributed in the rubber material. This is achieved by taking in the moisture inside through channels formed in the rubber material. In the present embodiment, the sensing rubber composition 11 has an average bulk volume of 0.15 ml or more and 0.50 ml or less of the undissolved deliquescent substance and electrolyte solution per 1 cm ³ of the sensing rubber composition 11. (preferably 0.25 ml or more and 0.35 ml or less). Further, in this embodiment, the conductivity of the electrolyte solution is 1×10 ⁻³ S/cm or more.

The sensing rubber composition 11 holds an electrolyte solution within the channel. Therefore, by bringing the electrodes 12, 13 into contact with the sensing rubber composition 11, the electrodes 12, 13 come into contact with the electrolyte solution within the channel. Therefore, in the rubber sensor 10, the electrodes 12 and 13 having different ionization tendencies are in contact with the electrolyte solution without being in direct contact with each other.

In this embodiment, the electrode 12 has a lower ionization tendency than the electrode 13 (including cases in which it does not become ions), and the electrode 12 functions as a positive electrode, and the electrode 13 functions as a negative electrode. Examples of the combination of electrodes 12 and 13 include a combination of a copper rod as a positive electrode and an aluminum rod as a negative electrode, or a carbon rod as a positive electrode and a zinc-plated iron wire as a negative electrode. Examples include combinations of materials. The electrodes 12 and 13 do not need to be rod-shaped; for example, film-shaped electrodes may be used.

When both the electrode as a positive electrode and the electrode as a negative electrode are made into a film, three film-like sensing rubber compositions (hereinafter referred to as first, second, and third sensing rubber compositions) are prepared, The electrode as a positive electrode is sandwiched between the first and second sensing rubber compositions, and the electrode as a negative electrode is sandwiched between the second and third sensing rubber compositions to increase the contact area between the electrode and the sensing rubber composition. You can also do this.

In this embodiment, as shown in FIG. 1, the electrodes 12 and 13 are formed into rod shapes, and by inserting the electrodes 12 and 13 into the sensing rubber composition 11, the contact area of the electrode 12 with the electrolyte solution and the contact area of the electrode 13 are changed. The contact area with the electrolyte solution is increased. Note that there are no restrictions on the position or direction in which the electrodes 12 and 13 are inserted.
Here, it has been confirmed through experimental verification using a voltmeter that a potential difference (voltage) is generated between the electrodes 12 and 13 of the rubber sensor 10. This means that electrons move from the negative electrode 13 to the positive electrode 12, and the rubber sensor 10 functions as a battery (generates electricity).

In the sensing rubber composition 11, the property of the deliquescent substance distributed on the surface and inside of the rubber material to absorb moisture in the air is, in principle, permanent; When exposed to an unusual environment (excluding an environment where the absolute humidity is 1% or less), the state in which the electrolyte solution is retained in the channel continues semi-permanently. Therefore, the power generation function of the rubber sensor 10 continues for a long period of time. Regarding this, it has been confirmed through experimental verification that a potential difference occurs between the electrodes 12 and 13 in the rubber sensor 10 that has been manufactured for more than half a year.

Further, the rubber sensor 10 has an electrode whose ionization tendency changes depending on the application of a mechanical load to the sensing rubber composition 11, the application of heat to the sensing rubber composition 11, or the application of a voltage to the sensing rubber composition 11. It was confirmed through experimental verification that the potential difference between 12 and 13 changes. Therefore, the rubber sensor 10 can detect mechanical load, heat application, and voltage application to the sensing rubber composition 11 based on the potential difference between the electrodes 12 and 13.

Furthermore, by changing the position of the sensing rubber composition 11 to which a mechanical load is applied, the position of the sensing rubber composition 11 to which heat is applied, or the position of the sensing rubber composition 11 to which a voltage is applied, the electrode It was also confirmed through experimental verification that the potential difference between 12 and 13 changes. Therefore, by using the rubber sensor 10, it is possible to detect the position where various physical loads are applied to the sensing rubber composition 11.

The sensing function and power generation function of the rubber sensor 10 described up to this point can be achieved regardless of the shape of the sensing rubber composition 11. This is because the channels for holding the electrolyte solution in which the deliquescent substance is dissolved are uniformly formed in the sensing rubber composition 11, and even if the sensing rubber composition 11 is separated into multiple pieces, the individual A plurality of rubber sensors can be produced by having each piece function as a sensing rubber composition and contacting each piece with a plurality of electrodes having different ionization tendencies.

Further, from the viewpoint of enabling the rubber sensor 10 to stably detect various physical loads (mechanical load, application of heat, application of voltage, etc.), it is important to apply physical loads to the sensing rubber composition 11. It is important that the potential difference between the electrodes 12 and 13 changes significantly, and for this purpose, it is suitable to mix a conductive filler into the rubber material. This is considered to be because the electrical contact area between the electrode 12 (the same applies to the electrode 13) and the sensing rubber composition 11 is expanded through the filler.

As fillers, carbon nanotubes, graphene, carbon black, carbon nanofibers, carbon nanohorns, graphite, Ketjen black, iron powder, etc. can be employed. Here, if the ratio of the filler to 100% by mass of the rubber material is less than 0.5% by mass, it is not possible to stably make a change in the potential difference between the electrodes (between the positive electrode and the negative electrode) noticeable. Therefore, the ratio of the filler to 100% by mass of the rubber material is preferably 0.5% by mass or more. On the other hand, if the ratio of the filler to 100% by mass of the rubber material is too large (for example, more than 10% by mass in the case of highly conductive fillers such as carbon nanotubes and Ketjen black), the electrolyte solution-containing rubber composition may become electrically It has the characteristics of an electric conductor, and the sensing function and power generation function of the rubber sensor may be impaired.

Further, the sensing rubber composition 11 according to an embodiment of the present invention, together with the plurality of electrodes 12 and 13 attached in contact with the sensing rubber composition 11, constitutes the rubber sensor 10 that detects a mechanical load. The composition includes a rubber material in which a carrier capable of supporting a deliquescent substance is distributed and a flow path is formed, the electrolyte solution in which the deliquescent substance is dissolved is held in the flow path, and a mechanical load is applied. is given to change the potential difference between one electrode and another electrode having a different ionization tendency from that electrode.

Sensing rubber composition 11 can be manufactured through the following steps.
First step: A mixture of a deliquescent substance and water is put into a container together with a carrier, and the mixture is supported on the carrier.
Second step: A carrier carrying the mixture is added to an uncured elastomer to which a curing agent and a nonpolar solvent have been added and mixed.
Third step: The elastomer in which the nonpolar solvent and carrier are uniformly distributed is dried and cured.

The nonpolar solvent suppresses the deliquescent substance supported on the carrier in the first step from separating from the carrier and flowing into the elastomer by mixing in the second step. Further, the nonpolar solvent evaporates during curing of the elastomer in the third step, forming channels in the elastomer.
In addition, the material for which the first and second steps have been completed (the third step has not been performed) is applied as a paint to another object, the paint is cured by ultraviolet rays or heat, and the sensing rubber composition is applied to the same object. It is also possible to form a layer of

It is also possible to design a tire with the rubber sensor described so far. By including the rubber sensor in the tire, it becomes possible to detect, for example, a location where an excessive load is applied to the tire and the magnitude of the load. It is also possible to design a tire with only the sensing rubber composition and have the electrodes outside the tire. Note that the rubber sensor and the sensing rubber composition can also be used as components of rubber products other than tires, such as seismic isolation rubber, hoses, belts, rubber crawlers, and rubber bearings.

Next, an experiment conducted to confirm the effects of the present invention will be described.

<Mechanical load experiment>
Additives made by mixing an aqueous magnesium chloride solution as an electrolyte solution and carbon black (MA100 from Mitsubishi Chemical Corporation) as a carrier are added to silicone (KE-26 from Shin-Etsu Chemical Co., Ltd.) with a nonpolar solvent (Sankyo Chemical Co., Ltd.). Paint thinner A (s)) was added and mixed, and then carbon nanotubes (Durobeads from Mitsubishi Corporation, an amount equivalent to 5% by mass of silicone) as a conductive filler were added and mixed. It was dried to form a first sensing rubber composition 21 (see FIG. 2).

As shown in FIG. 2, the first sensing rubber composition 21 is coated with two positive electrodes 22, 22a made of carbon rods and three negative electrodes 23, 23a, 23b made of galvanized iron wire. was inserted to produce a first sample 20 of a rubber sensor. The first sensing rubber composition 21 had a length of 90 mm, a width of 75 mm, and a thickness of 5 mm. In the first sample 20, the positive electrodes 22, 22a are inserted 5 mm into the upper left side and the center left side of the first sensing rubber composition 21, and the negative electrodes 23, 23a, 23b are inserted into the upper right side of the first sensing rubber composition 21. , 5 mm each were inserted into the center right side and the lower right side.

As shown in Figure 2, one longitudinal side of a cylindrical wooden bar with a diameter of 5 mm is pressed with a force of 10 N/m ² against the 15 locations of the first sample 20 with the numbers circled. Then, the potential difference between one positive electrode selected from the positive electrodes 22 and 22a and one negative electrode selected from the negative electrodes 23, 23a, and 23b was measured. The vertical and horizontal pitches of the locations where the bar material was pressed against the first sample 20 (hereinafter also referred to as "force application locations") were each 20 mm. The 15 force application locations were divided into four groups, A, B, C, and D, depending on the distance from the straight line connecting the positive and negative electrodes where the potential difference was measured. The group closest to the straight line was group A, the group second closest to the straight line was group B, the group third closest to the straight line was group C, and the group furthest to the straight line was group D.

The measurement results of the potential difference between the positive electrode 22 and the negative electrode 23 are shown in FIG. 3, the measurement results of the potential difference between the positive electrode 22a and the negative electrode 23 are shown in FIG. 4, the measurement results of the potential difference between the positive electrode 22 and the negative electrode 23a are shown in FIG. FIG. 6 shows the measurement results of the potential difference between the positive electrode 22 and the negative electrode 23b, FIG. 7 shows the measurement result of the potential difference between the positive electrode 22a and the negative electrode 23b, and FIG. 8 shows the measurement result of the potential difference between the positive electrode 22a and the negative electrode 23b. In FIGS. 3 to 8, the encircled numbers 1 to 15 mean 15 force application points. In FIGS. 3 to 8, the potential difference when the bar is not pressed is taken as a reference value (0V), and the amount of change in the potential difference when the bar is pressed with respect to the reference value is shown.

From the measurement results shown in Figures 3 to 8, the amount of change relative to the reference position tended to be the largest in group A, the second largest in group B, the third largest in group C, and the smallest in group D. . In Group A, it was confirmed that the amount of change from the reference position tended to be larger at the force applying point near the positive electrode or the negative electrode than at the force applying point located between the positive electrode and the negative electrode.

<Heat application experiment>
Using a material in which the carbon nanotubes were removed from the material used to produce the first sensing rubber composition 21, a rubber tube measuring 90 mm in length, 90 mm in width, and 5 mm in thickness was prepared as shown in FIG. A second sensing rubber composition 31 of No. 2 is prepared, and a positive electrode 22 and a negative electrode 23 (each used in a mechanical load experiment, the same shall apply hereinafter) are inserted into the second sensing rubber composition 31 to prepare a second sample of a rubber sensor. 30 were produced.

The proportion of carbon nanotubes in the material used to produce the first sensing rubber composition 21 was changed to 0.2% by mass of silicone, and the first sensing rubber composition 21 was made with a size of 90 mm in length, 90 mm in width, and 5 mm in thickness. The sensing rubber composition No. 3 was prepared, and the positive electrode 22 and the negative electrode 23 were inserted into the third sensing rubber composition to prepare a third sample of a rubber sensor.
Furthermore, a fourth sensing rubber composition having a size of 90 mm in length, 90 mm in width, and 5 mm in thickness was prepared using the same material as that used for preparing the first sensing rubber composition 21. A fourth sample of a rubber sensor was prepared by inserting the positive electrode 22 and the negative electrode 23 into the sensing rubber composition of No. 4.

In the second sample 30, as shown in FIG. 9, the positive electrode 22 is inserted 5 mm into the upper right side of the second sensing rubber composition 31, and the negative electrode 23 is inserted 5 mm into the lower right side of the second sensing rubber composition 31. It was This was the same for the third and fourth samples.

First, with respect to the second sample 30, a soldering iron at approximately 220°C (220°C ± 10°C) was applied to the three locations on which the numbers 1 to 3 are circled on the second sample 30 shown in FIG. was brought into contact with the second sample 30 without applying substantial pressure, and the potential difference between the positive electrode 22 and the negative electrode 23 was measured. The measurement results are shown in FIG.
From the measurement results in FIG. 10, it is clear that the potential difference between the positive electrode 22 and the negative electrode 23 changes as the position of applying heat to the second sample 30 changes, and that even if the rubber sensor does not contain carbon nanotubes, the positive electrode 22 and the negative electrode It was confirmed that a potential difference was generated at 23.

Next, for each of the third and fourth samples, heat a soldering iron at approximately 220°C (220°C ± 10°C) at the position corresponding to the circled position of the number 3 on the second sample 30. were brought into contact with each other without applying substantial pressure, and the potential difference between the positive electrode 22 and the negative electrode 23 was measured. The measurement results of the third sample and the measurement results of the fourth sample are shown in FIGS. 11 and 12, respectively.

From the measurement results shown in Figures 11 and 12, the time from the start of increase in potential difference to the peak was approximately 315 seconds for the third sample containing 0.2% by mass of carbon nanotubes in the silicone rubber, whereas In the fourth sample containing 0.5% by mass of carbon nanotubes, the time from the start of increase in potential difference to the peak was about 260 seconds. Furthermore, in the third sample, the difference between the potential difference when the potential difference started to increase and the potential difference when the potential difference peaked was 0.15V, whereas in the fourth sample, the difference between the two potential differences was 0.26V. Met.

<Voltage application experiment>
Using the same material as that used to produce the first sensing rubber composition 21, a fifth sensing rubber composition with dimensions of 75 mm in length, 150 mm in width, and 7 mm in thickness as shown in FIG. 13 was prepared. 41, the positive electrode 22 was inserted 5 mm into the upper right side of the fifth sensing rubber composition 41, the negative electrode 23 was inserted 5 mm into the lower right side of the fifth sensing rubber composition 41, and a fifth sample 40 of the rubber sensor was prepared. Created.

The positive electrode of an application device that applies a DC voltage of 5 V is brought into contact with the surface of the fifth sample 40 at the position surrounded by the + shown in FIG. 13, and the contact position of the negative electrode of the application device is sequentially changed. The potential difference between the positive electrode 22 and the negative electrode 23 was measured. The contact positions of the negative electrode of the application device were the positions where the numbers 1 to 59 were circled in FIG. The measurement results are shown in FIG. Note that the numbers attached to the bar graphs in FIG. 14 mean the contact positions of the negative electrode of the application device.
From the measurement results shown in FIG. 14, it was confirmed that the potential difference between the positive electrode 22 and the negative electrode 23 changes by changing the location where voltage is applied to the fifth sample 40.

Next, the positive electrode of the application device is brought into contact with the surface of the fifth sample 40 at the position surrounded by the + shown in FIG. The potential difference between the positive electrode 22 and the negative electrode 23 was measured by sequentially changing to the eight positions circled. The measurement results are shown in FIG. The numbers attached to the bar graphs in FIG. 16 mean the contact positions of the negative electrode of the application device.
It was also confirmed from the measurement results shown in FIG. 16 that the potential difference between the positive electrode 22 and the negative electrode 23 changes by changing the location where voltage is applied to the fifth sample 40.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and any changes in conditions that do not depart from the gist are within the scope of the present invention.
For example, a conductive filler may not be mixed into the sensing rubber composition. When mixing a conductive filler into the sensing rubber composition, the proportion of the filler to the rubber material may be less than 0.5% by mass, or depending on the type of filler, the proportion may exceed 10% by mass. . In the rubber sensor, even if heat is applied to the sensing rubber composition, the potential difference between two electrodes having different ionization tendencies does not need to change.

Furthermore, the output current of the rubber sensor can be increased by increasing the contact area between the electrode and the sensing rubber composition. A rubber sensor 50 in which the contact area between the electrode 51 and the sensing rubber composition 52 is increased will be described with reference to FIGS. 17(A) and 17(B).
In the rubber sensor 50, as shown in FIGS. 17A and 17B, an electrode 51 as a negative electrode and a sensing rubber composition 52 are each shaped like a band, and an electrode 53 as a positive electrode is shaped like a rod.

Sensing rubber composition 52 is longer than electrode 51. In the rubber sensor 50, the power generation function enhancing part 54 is formed by a cylindrical object wound with one side surface of the whole electrode 51 and one side surface of a part of the sensing rubber composition 52 in surface contact, and the power generation function strengthening part 54 is formed. A plate-shaped sensor function section 55 is formed by an area excluding the area of the sensing rubber composition 52 that constitutes the function reinforcement section 54 . The electrode 53 passes through the axis of the power generation function enhancing portion 54 and is in contact with the sensing rubber composition 52 . Electrode 51 and electrode 53 are not in contact with each other.

Since the power generation function enhancing portion 54 has a large contact area between the electrode 51 and the sensing rubber composition 52, it can contribute to increasing the output current. The sensor function section 55 has a smaller contribution to the power generation function than the power generation function enhancement section 54, and is suitable for use as a section to which a physical load is applied.
The power generation function enhancing section 54 is kept in a cylindrical shape by being housed in an insulating case (not shown). If a through hole through which the electrode 53 passes and a through hole through which the sensor function part 55 of the sensing rubber composition 52 protrudes outside the case are formed in the case, the rubber sensor 50 becomes capable of applying voltage and current to the outside. . As the electrode 51, for example, aluminum foil can be used, and as the electrode 53, for example, a carbon bar can be used.

Needless to say, an increase in the output current of a rubber sensor can be contributed not only by increasing the contact area between the negative electrode and the sensing rubber composition, but also by increasing the contact area between the positive electrode and the sensing rubber composition. For example, by preparing two strip-shaped electrodes and two strip-shaped sensing rubber compositions, and winding one electrode, one sensing rubber composition, the other electrode, and the other sensing rubber composition in this order. , it becomes possible to increase the contact area of both electrodes with the sensing rubber composition. Furthermore, a plurality of sets of a strip-shaped electrode as a positive electrode, a strip-shaped sensing rubber composition, a strip-shaped electrode as a negative electrode, and a strip-shaped sensing rubber composition in order of surface contact may be stacked together. , there are a plurality of electrodes each serving as a positive electrode and a plurality of electrodes serving as a negative electrode.

10: Rubber sensor, 11: Sensing rubber composition, 12, 13: Electrode, 20: First sample, 21: First sensing rubber composition, 22, 22a: Positive electrode, 23, 23a, 23b: Negative electrode, 30: Second sample, 31: Second sensing rubber composition, 40: Fifth sample, 41: Fifth sensing rubber composition, 50: Rubber sensor, 51: Electrode, 52: Sensing rubber composition, 53: Electrode , 54: Power generation function enhancement section, 55: Sensor function section

Claims (10)

A rubber sensor that detects mechanical loads,
A sensing rubber that is capable of supporting a deliquescent substance, has a rubber material in which a carrier holding the deliquescent substance is distributed, and has a flow path formed therein, and holds an electrolyte solution in which the deliquescent substance is dissolved in the flow path. a composition;
comprising a plurality of electrodes that are in contact with the sensing rubber composition and are not in contact with each other,
A rubber sensor characterized in that a potential difference between one of the electrodes and another electrode having a different ionization tendency from that electrode changes as a mechanical load is applied to the sensing rubber composition. 2. The rubber sensor according to claim 1, wherein the rubber material is mixed with a conductive filler. 3. The rubber sensor according to claim 2, wherein a ratio of the filler to 100% by mass of the rubber material is 0.5% by mass or more. 2. The rubber sensor according to claim 1, wherein the potential difference between the one electrode and the other electrode changes also by application of heat to the sensing rubber composition. A sensing rubber composition constituting a rubber sensor for detecting mechanical loads together with a plurality of electrodes attached in contact, the composition comprising:
A carrier capable of supporting a deliquescent substance and holding the deliquescent substance is distributed thereon, and has a rubber material in which a flow path is formed, and an electrolyte solution in which the deliquescent substance is dissolved is held in the flow path. 1. A sensing rubber composition characterized in that a potential difference between one of the electrodes and another electrode having a different ionization tendency from that of the electrode is changed when a load is applied to the sensing rubber composition. 6. The sensing rubber composition according to claim 5, wherein a conductive filler is mixed in the rubber material. 7. The sensing rubber composition according to claim 6, wherein the proportion of the filler based on 100% by mass of the rubber material is 0.5% by mass or more. 6. The sensing rubber composition according to claim 5, wherein the sensing rubber composition changes the potential difference between the one electrode and the other electrode even when heat is applied. A tire having a rubber sensor that detects a mechanical load,
The rubber sensor includes a rubber material capable of supporting a deliquescent substance, in which a carrier holding the deliquescent substance is distributed , and a flow path is formed, and an electrolyte solution in which the deliquescent substance is dissolved is contained in the flow path. comprising a sensing rubber composition to be held, and a plurality of electrodes that are in contact with the sensing rubber composition but not in contact with each other, and the potential difference between one of the electrodes and the other electrodes having a different ionization tendency from that electrode is: A tire characterized in that the sensing rubber composition changes when a mechanical load is applied to it. A tire having a sensing rubber composition constituting a rubber sensor for detecting mechanical loads together with a plurality of electrodes attached in contact, the tire comprising:
The sensing rubber composition has a rubber material capable of supporting a deliquescent substance, in which a carrier holding the deliquescent substance is distributed and a channel is formed, and the deliquescent substance is dissolved in the channel. 1. A tire that holds an electrolyte solution and changes the potential difference between one of the electrodes and another electrode having a different ionization tendency by applying a mechanical load.

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