JP6783255B2 - Vibration sensor, vibration measurement method and vibration sensor manufacturing kit - Google Patents

Description

The present invention relates to a vibration sensor, a vibration measuring method, and a kit for manufacturing a vibration sensor.

Conventionally, it has been practiced to measure the vibration of parts such as pipes and rotating parts where vibration can occur. As a method for measuring such vibration, a vibration sensor including a piezoelectric element is used because the measurement is relatively simple and there is little change over time.

As the vibration sensor, a vibration sensor including a piezoelectric element such as a single crystal of crystal or barium titanate and a weight has been developed. Specifically, vibration is generated by applying a compressive force to the piezoelectric element. A compression type vibration sensor for measuring and a shear type vibration sensor for measuring vibration by applying a shearing force to the piezoelectric element have been developed.

Further, Patent Document 1 discloses a membrane vibration sensor in which a weight is bonded to a polymer piezoelectric film.

Japanese Unexamined Patent Publication No. 56-012513

In the vibration sensor, a compressive force or a shearing force is applied to the piezoelectric element by the vibration of the weight contained in the sensor, and the vibration is detected.
However, since these sensors require a weight, there is a problem that the mass of the sensor becomes heavy and the sensor size becomes large.
When the mass of the sensor becomes heavy, the mass of the sensor is added to the vibrating body and the natural frequency of the vibrating body becomes small, so that the original vibration information of the vibrating body tends not to be obtained, and the sensor size becomes large. Then, there is a problem that the sensor cannot be installed in a desired place such as a narrow part.

Further, without using the weight, one surface of the piezoelectric element is brought into contact with a vibrating body and the other surface is brought into contact with a non-vibrating body such as the ground to generate a charge in the piezoelectric element and detect vibration. A vibration sensor is also considered, but such a vibration sensor has a problem that the place where it can be installed is limited and the sensor size becomes large.

In one embodiment of the present invention, there is provided a vibration sensor that can be easily installed on the surface of a vibrating body such as a pipe or a rotating system component and can detect the vibrating state of the vibrating body without using a weight. With the goal.

Under such circumstances, as a result of diligent studies to solve the above-mentioned problems, the present inventors have found that the above-mentioned object can be achieved by the vibration sensor having a specific structure, and have completed the present invention. It was.
A configuration example of the present invention is as follows.

[1] A vibration transmitter fixed to the vibrating body and
A vibration detection laminate, which is a laminate of a piezoelectric element layer and a vibration absorption layer, is provided.
The vibration detection laminate is provided so that the vibration of the vibrating body is suppressed by the vibration absorbing layer on one surface of the piezoelectric element layer and transmitted by the vibration transmitter on the other surface of the piezoelectric element layer. Have, have
A vibration sensor that detects the vibration of a vibrating body.

[2] The vibration sensor according to [1], wherein the vibration transmissibility of the vibration absorption layer is 1 or less.
[3] The vibration absorbing layer includes any one of a layer made of gel, a layer made of natural rubber, a layer made of synthetic rubber, a layer made of an elastomer, a resin foam, and a woven fabric or a non-woven fabric made of a fiber material. The vibration sensor according to [1] or [2].

[4] The vibration sensor according to any one of [1] to [3], wherein the piezoelectric element layer contains a porous resin sheet.
[5] The piezoelectric element layer contains a non-woven fabric or woven fabric made of fibers.
The vibration sensor according to any one of [1] to [4], wherein the fiber is made of a polymer having no dipole due to a molecular and crystal structure.
[6] The vibration sensor according to [5], wherein the polymer is polytetrafluoroethylene.

[7] The ratio Z1 / Z2 of the acoustic impedance (Z1) of the material of the vibrating body surface of the portion in contact with the vibrating body and the acoustic impedance (Z2) of the material of the vibrating body is 0.2 to 5.0. The vibration sensor according to any one of [1] to [6], which is in the range of.

[8] The vibration sensor according to any one of [1] to [7], wherein the vibration absorbing layer is in contact with the vibrating body among the vibration detecting laminated bodies.

[9] A vibration measuring method for detecting the vibration of a vibrating body by installing the vibration sensor according to any one of [1] to [8] on the surface of the vibrating body.

[10] A vibration transmitter used by fixing to a vibrating body,
Piezoelectric element and
Including vibration absorber
The piezoelectric element and the vibration absorber so that the vibration of the vibrating body is suppressed by the vibration absorber on one surface of the piezoelectric element and transmitted by the vibration transmitter on the other surface of the piezoelectric element. Is placed and used,
Vibration sensor manufacturing kit.

[11] A vibration measuring method for detecting vibration of a vibrating body by installing a vibration sensor obtained from the vibration sensor manufacturing kit according to [10] on the surface of the vibrating body.

According to one embodiment of the present invention, it can be easily installed on the surface of a vibrating body such as a pipe or a rotating system component, and the vibrating state of the vibrating body can be easily detected without using a weight. ..
In particular, according to one embodiment of the present invention, the mounting and handling are easy, the weight and size can be reduced, and even if the vibrating body surface is a curved surface or the like in a desired place such as a narrow portion. It can be easily installed and the vibration of the vibrating body can be easily detected.

FIG. 1 is a schematic cross-sectional view of a vibration sensor according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a vibration sensor according to an embodiment of the present invention.

≪Vibration sensor≫
Hereinafter, the vibration sensor according to the embodiment of the present invention will be described with reference to FIG. 1, which is a schematic cross-sectional view of the embodiment.
The vibration sensor 10 according to the embodiment of the present invention is a vibration sensor that detects the vibration of the vibrating body 5, and includes a vibration transmitting body 3 fixed to the vibrating body 5, a piezoelectric element layer 2 and a vibration absorbing layer 1. A vibration detection laminated body, which is a laminated body, is provided, and the vibration of the vibrating body 5 is suppressed by the vibration absorbing layer 1 on one surface of the piezoelectric element layer 2, and on the other surface of the piezoelectric element layer 2. It is a vibration sensor having the vibration detection laminate so as to be transmitted by the vibration transmitter 3.
In one embodiment of the present invention, instead of the conventionally used contact with a weight or a non-vibrating body (eg, the ground), the vibration of the vibrating body is suppressed by the vibration absorbing layer on one surface of the piezoelectric element layer. By transmitting the vibration of the vibrating body to the other surface by the vibrating body, a compressive force or a shearing force can be applied to the piezoelectric element layer, so that the piezoelectric element layer is charged by the vibration of the vibrating body. By measuring this amount of charge, it is possible to detect the presence or absence of vibration, the magnitude of vibration, and the like.
According to the vibration sensor according to the embodiment of the present invention, the mounting and handling are easy, the weight and size can be reduced, and the desired place such as a narrow portion, particularly the surface of the vibrating body is curved. It can be easily installed even in the case of the above, and vibration can be easily detected even when the dimensional deformation of the vibrating body itself (eg, the diameter change of the pipe) does not occur.

The vibration sensor according to the embodiment of the present invention is not particularly limited as long as it has a vibration transmitter and a vibration detection laminate, and may include conventionally known layers, members, and the like. Examples of the member include a charge transmission means for transmitting the electric charge generated in the piezoelectric element layer, an amplifier for amplifying the electric charge transmitted by the charge transmission means, and outputting a voltage signal.

The vibration sensor according to the embodiment of the present invention is used by being attached to a part of the surface of the vibrating body. When the vibrating body is, for example, a pipe, the vibration sensor according to the embodiment of the present invention may be wound around the vibrating body so as to cover the outer periphery thereof. Further, in the vibration sensor according to the embodiment of the present invention, after the vibration detection laminate is housed in the vibration transmitter, the obtained sensor may be attached to the vibration body, or the vibration detection laminate may be attached to the vibration body. After that, the vibration transmitter may be attached to the vibrating body so as to cover the vibration detecting laminate, or for example, after attaching the vibration absorber to the vibrating body, the piezoelectric element layer is attached on the vibration transmitting body, and then the obtained body is obtained. The vibration transmitter may be attached to the vibration body so as to cover the vibration detection laminate.

<Vibration detection laminate>
The vibration sensor according to the embodiment of the present invention has a vibration detection laminate which is a laminate of a piezoelectric element layer and a vibration absorption layer.
The vibration detection laminate is arranged so that the vibration of the vibrating body is suppressed by the vibration absorbing layer on one surface of the piezoelectric element layer and transmitted by the vibration transmitter on the other surface of the piezoelectric element layer. If this is done, there is no particular limitation, and even if the vibration absorbing layer 1 is arranged on the vibrating body 5 side and the piezoelectric element layer 2 is arranged between the vibration absorbing layer 1 and the vibration transmitting body 3, as shown in FIG. Often, as shown in FIG. 2, the piezoelectric element layer 2 is arranged on the vibrating body 5 side via the vibration transmitting body 3, and the vibration absorbing layer 1 is arranged on the side of the piezoelectric element layer 2 opposite to the vibrating body 5 side. You may. Further, the vibration detection laminated body may be arranged in an accommodation space formed between the vibration transmitter and the vibration body, or in the accommodation space when the vibration transmitter has an accommodation space inside. Even if the vibration detection ability is high, the surface of the vibrating body is curved, or even if it has a complicated structure, it is possible to manufacture a vibrating sensor having an arbitrary shape that follows the surface of the vibrating body. On the other hand, it is possible to install the vibration sensor according to the embodiment of the present invention by a simple method such as winding or pasting without any special device, and the normal line on the surface of the vibrating body and the piezoelectric element layer. Vibration on the vibrating body 5 side from the viewpoint that it becomes easy to install the vibration sensor according to the embodiment of the present invention in a state where the direction of the polarization axis (direction corresponding to the piezoelectric constant d33) is substantially the same. It is preferable that the absorption layer 1 is arranged and the piezoelectric element layer 2 is arranged between the vibration absorption layer 1 and the vibration transmitter 3. Further, the vibration detection laminate is arranged in the accommodation space inside the vibration transmitter from the viewpoints of ease of installation on the vibration body and prevention of damage to the vibration detection laminate when installed on the surface of the vibration body. Is preferable.

The vibration detection laminate is not particularly limited to include the piezoelectric element and the vibration absorber, and may include a conventionally known layer such as an adhesive layer.
In the vibration sensor according to the embodiment of the present invention, the vibration of the vibrating body is suppressed by the vibration absorbing layer on one surface of the piezoelectric element layer, and transmitted by the vibration transmitter on the other surface of the piezoelectric element layer. As described above, since the vibration detection laminated body is provided, the vibration of the vibrating body needs to be reliably transmitted to one surface of the piezoelectric element layer. Therefore, when the piezoelectric element layer is present on the vibration transmitter side as shown in FIG. 1, the piezoelectric element layer and the vibration transmitter are always in contact with each other, for example, in a state of being bonded by an adhesive layer or the like. Preferably, when the piezoelectric element layer is present on the vibrating body side, the piezoelectric element layer and the vibrating body have a vibration transmitter in between and are always in contact with each other, for example, in a state of being bonded by an adhesive layer or the like. Further, it is preferable that the piezoelectric element layer and the vibration absorbing layer are always in contact with each other, for example, in a state of being bonded by an adhesive layer or the like.

Further, as shown in FIG. 1, in the vibration detection laminated body, one surface of the laminated body is in contact with the vibrating body 5 (via an adhesive layer or the like), and the side of the laminated body in contact with the vibrating body 5 It is preferable that the surface opposite to the vibration transmitter 3 is in contact with the vibration transmitter 3 (via an adhesive layer or the like), and the surfaces other than these two surfaces of the laminated body are not in contact with the vibration transmitter 3. It is preferable from the viewpoint that the vibration of the vibrating body 5 can be detected more accurately.

<Vibration absorption layer>
The vibration absorbing layer is not particularly limited as long as it can absorb part or all of the vibration of the vibrating body, and is preferably a layer capable of shielding the transmission of vibration, and a layer made of a vibration-proof material is preferable.

The vibration transmissibility of the vibration absorption layer is preferably 1 or less, more preferably 0.5 or less, from the viewpoint of obtaining a vibration sensor having higher vibration detection ability.
For the vibration transmission rate, the output voltage when the vibration of the vibrating body is directly measured by the acceleration sensor is V _0, and the output voltage when measured through the vibration absorbing layer between the vibrating body and the acceleration sensor is V. It is a value calculated by V / V ₀ .

Further, the loss coefficient measured in accordance with JIS K 7244-1 of the vibration absorption layer is preferably 0.2 or more, more preferably 0.2 or more, from the viewpoint of obtaining a vibration sensor having higher vibration detection ability. Is 0.3 or more.

Specifically, the vibration absorbing layer includes a layer made of gel such as acrylic, urethane, or silicone; a layer made of natural rubber; a layer made of synthetic rubber such as butyl rubber or silicone rubber; a layer made of elastomer; Resin foams obtained by foaming polypropylene, polyethylene, polycarbonate, etc .; woven fabrics or non-woven fabrics made of fiber materials such as synthetic fibers, semi-synthetic fibers, regenerated fibers, and natural fibers can be mentioned, and among these, vibration detection ability is higher. A layer made of gel is preferable from the viewpoint of obtaining a high vibration sensor, and a silicone-based gel is particularly preferable when the vibration of a vibrating body at a high temperature (about 100 ° C. or higher) is to be measured.
The vibration absorbing layer is a layer containing two or more kinds of a gel layer, a natural rubber layer, a synthetic rubber layer, an elastomer layer, a resin foam, a woven fabric made of a fiber material, a non-woven fabric, and the like. There may be.

The thickness of the vibration absorbing layer may be appropriately selected according to a desired application, and is not particularly limited as long as it can absorb even a part of the vibration of the vibrating body, but is preferably 0.01 to 10 mm, lightweight and compact. It is more preferably 0.1 to 2 mm from the viewpoint that a vibration sensor can be obtained.

<Piezoelectric element layer>
The piezoelectric element layer is not particularly limited as long as the piezoelectric element is included, and may include conventionally known layers. Specifically, electrode layers, surface smoothing layers, protective layers, etc. are provided on both sides of the piezoelectric element. Examples thereof include a laminate in which an insulating layer, an adhesive layer and the like are present.

The shape and size of the piezoelectric element layer are not particularly limited as long as the vibration of the vibrating body can be detected, but when the piezoelectric element layer 2 is arranged so as to be in contact with the vibration transmitter 3 as shown in FIG. 1, the vibrating body is more sensitive. It is preferable that the surface of the piezoelectric element layer 2 on the side in contact with the vibration transmitter 3 is substantially parallel to the surface of the vibration body 5 from the viewpoint of being able to detect the vibration of the vibration body 5.

The piezoelectric element layer may be an organic piezoelectric layer such as a sheet made of a piezoelectric resin or a porous resin sheet, or a layer made of an inorganic piezoelectric material such as quartz, barium titanate, or lead titanium zirconate. It may be monomorphic, bimorphic or laminated.

The piezoelectric element layer has a piezoelectric constant d33 of preferably 20 × 10 ^-12 C / N or more, from the viewpoint that a vibration sensor having better vibration detection ability can be obtained by detecting vibration in the thickness direction of the piezoelectric element. It is more preferable that the piezoelectric element layer is made of a material having a value of 100 × 10 ^-12 C / N or more, and more preferably 200 × 10 ^-12 C / N or more.

As the piezoelectric element layer, a porous resin sheet is preferable, and by using the porous resin sheet, the charge responsiveness to minute vibration is high, the vibration detection ability is high, and the charge can be retained even in a high temperature environment. It is possible to obtain a vibration sensor having excellent detection ability, high flexibility, excellent impact resistance, and light weight.

Further, when the porous resin sheet is used, it is easy to mold it into an arbitrary shape such as thinning or increasing the area, and the surface of the vibrating body is curved or has a complicated structure. Even so, it is possible to manufacture a vibration sensor having an arbitrary shape that follows the surface of the vibrating body. Therefore, when the porous resin sheet is used, the vibration sensor according to the embodiment of the present invention can be installed on the vibrating body by a simple method such as winding or pasting without any special device. This is possible, and it becomes easy to install the vibration sensor according to the embodiment of the present invention in a state where the normal of the surface of the vibrating body and the direction of the polarization axis of the piezoelectric element layer are substantially the same.

The porous resin sheet is preferably a sheet made of an organic material capable of retaining an electric charge. Examples of the porous resin sheet made of such an organic material include a non-woven fabric or woven fabric made of fibers, a sheet-like foam made of an organic polymer, a stretched porous film made of an organic polymer, a matrix resin and an electric charge. A porous resin sheet containing inducible hollow particles (particles in which a conductive substance is attached to at least a part of the surface of the hollow particles), a phase separation agent dispersed in an organic polymer, and supercritical carbon dioxide. Examples thereof include a sheet formed by a method of forming pores by removing with an extractant such as.
Among these, a non-woven fabric or woven fabric made of polymer fibers is preferable from the viewpoints of durability and long-term maintenance of deformation performance.

The porous resin sheet contains one or more types of inorganic fillers as long as the effects of the present invention are not impaired, from the viewpoint of obtaining a piezoelectric element layer having a high charge retention amount and excellent piezoelectric characteristics. May be. As the inorganic filler, a filler having a higher dielectric constant than the polymer is preferable from the viewpoint of obtaining a sheet having a high piezoelectricity, and for example, an inorganic filler having a relative dielectric constant ε of 10 to 10000 is preferable. Specific examples of the inorganic filler include titanium oxide, aluminum oxide, barium titanate, lead zirconate titanate, zirconium oxide, cerium oxide, nickel oxide, tin oxide and the like.

The thickness of the porous resin sheet may be appropriately selected depending on the intended use, but is usually 10 μm to 1 mm, preferably 50 μm to 500 μm.

The porosity of the porous resin sheet is preferably 60% or more, more preferably 75% or more, still more preferably 80 to 99%, from the viewpoint of obtaining a piezoelectric element layer having high charge retention. The vacancy rate can be calculated by the following method.
(True Density of Resin-Apparent Density of Porous Resin Sheet) x 100 / True Density of Resin For the apparent density, a value calculated by using the weight of the porous resin sheet and the apparent volume is used.

Examples of the polymer constituting the fiber include a polymer having a volume resistance of 1.0 × 10 ¹³ Ω · cm or more, and examples thereof include polyamide resins (6-nylon, 6,6-nylon, etc.) and aromatics. Polyamide-based resin (aramid, etc.), polyolefin-based resin (polyethylene, polypropylene, etc.), polyester-based resin (polyethylene terephthalate, etc.), polyacrylonitrile, phenol-based resin, fluorine-based resin (polytetrafluoroethylene, polyvinylidene fluoride, etc.), Examples thereof include imide-based resins (polyethylene, polyamideimide, bismaleimide, etc.).

Among these, a polymer having no dipole due to its molecular and crystal structures is preferable from the viewpoint of excellent heat resistance and weather resistance. Examples of such polymers include polyolefin-based resins (polyethylene, polypropylene, ethylene-propylene resin, etc.), polyester-based resins (polyethylene elephthalate, etc.), polyurethane resins, polystyrene resins, non-fluorine-based resins such as silicone resins, and polytetra. Examples thereof include fluororesins such as fluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP).

Among these, from the viewpoint of heat resistance, weather resistance, etc., it is preferable that the polymer has a high continuous usable temperature and does not have a glass transition point in the operating temperature range of the vibration sensor. The continuous use temperature can be measured by the continuous use temperature test described in UL746B (UL standard), and is preferably 50 ° C. or higher, more preferably 100 ° C. or higher, still more preferably 200 ° C. or higher. .. Further, from the viewpoint of moisture resistance, it is preferable that the polymer exhibits water repellency.
As the polymer having these characteristics, for example, a polyolefin resin and a fluororesin are preferable, and in particular, the piezoelectric characteristics are deteriorated even when the vibration of a vibrating body at a high temperature (about 100 ° C. or higher) is to be measured. Fluororesin is more preferable, and PTFE is particularly preferable, from the viewpoint that a vibration sensor capable of detecting vibration without vibration can be obtained.

In particular, when PTFE is used as the polymer, a vibration sensor having an excellent balance of heat resistance, vibration detection ability and durability can be obtained, and the vibration sensor has a performance and a structure even in a high temperature / high pressure environment. Since it can be maintained, it can be suitably used as a vibration sensor for high-temperature vibrating body inspection.

The fibers have an average fiber diameter of preferably 0.05 to 50 μm, more preferably 0.1 to 20 μm, and even more preferably 0.3 to 5 μm. When the average fiber diameter is within the above range, a non-woven fabric or woven fabric showing high flexibility can be formed, and a sufficient space for holding a charge can be formed by increasing the fiber surface area, and a thin non-woven fabric or woven fabric can be formed. Even when it is formed, it is preferable in that the distribution uniformity of the fibers can be increased.

The average fiber diameter of the fibers can be adjusted by appropriately selecting the conditions for forming the fibers. For example, in the case of manufacturing by the electric field spinning method, the nozzle diameter that lowers the humidity during electric field spinning is used. There is a tendency that the average fiber diameter of the obtained fiber can be reduced by reducing the value, increasing the applied voltage, or increasing the voltage density.

For the average fiber diameter, 20 fibers were randomly selected from the obtained SEM images obtained by observing the fibers (group) to be measured with a scanning electron microscope (SEM) (magnification: 10000 times). The fiber diameter (major axis) of each fiber is measured, and it is an average value calculated based on the measurement result.

The coefficient of variation of the fiber diameter of the fiber calculated by the following formula is preferably 0.7 or less, more preferably 0.01 to 0.5. When the coefficient of variation of the fiber diameter is within the above range, the fiber has a uniform fiber diameter, and the non-woven fabric or woven fabric obtained by using the fiber has a higher porosity, and is therefore also porous with high charge retention. It is preferable because a resin sheet can be obtained.
Coefficient of variation of fiber diameter = standard deviation / average fiber diameter (Note that the "standard deviation" is the standard deviation of the fiber diameters of the 20 fibers).

The fiber length of the fiber is preferably 0.1 to 1000 mm, more preferably 0.5 to 100 mm, still more preferably 1 to 50 mm.

The fiber is produced by, for example, an electric field spinning method, a melt spinning method, a melt electrospinning method, a spunbond method (melt blow method), a wet method, or a spunlace method. The non-woven fabric or woven fabric formed from such fibers has a high porosity and a high specific surface area, so that a porous resin sheet having high piezoelectricity can be obtained.

[Electric field spinning method]
When forming a fiber made of a polymer by using an electric field spinning method, for example, a spinning liquid containing the polymer and, if necessary, a solvent is used.

The proportion of the polymer contained in the spinning solution is, for example, 5 to 100% by weight, preferably 5 to 80% by weight, and more preferably 10 to 70% by weight.
The polymer may be used alone or in combination of two or more.

The solvent is not particularly limited as long as it can dissolve or disperse the polymer, and for example, water, dimethylacetamide, dimethylformamide, tetrahydrofuran, methylpyrrolidone, xylene, acetone, chloroform, ethylbenzene, cyclohexane, benzene, sulfolane. , Methanol, ethanol, phenol, pyridine, propylene carbonate, acetonitrile, trichloroethane, hexafluoroisopropanol, diethyl ether. These solvents may be used alone or in combination of two or more.
The solvent is contained in the spinning solution, for example, from 0 to 90% by weight, preferably 10 to 90% by weight, and more preferably 20 to 80% by weight.

The spinning solution may further contain additives other than the polymer, such as inorganic fillers, surfactants, dispersants, charge modifiers, functional particles, adhesives, viscosity modifiers, fiber-forming agents and the like. .. These additives may be used alone or in combination of two or more.
In the spinning solution, when the solubility of the polymer in the solvent is low (for example, when the polymer is PTFE and the solvent is water), one kind or one is used from the viewpoint of retaining the polymer in a fibrous shape during spinning. It is preferable to contain two or more kinds of fiber forming agents.

The fiber-forming agent is preferably a polymer having high solubility in a solvent, for example, polyethylene oxide, polyethylene glycol, dextran, alginic acid, chitosan, starch, polyvinylpyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide. , Cellulose, polyvinyl alcohol and the like.
When the fiber forming agent is used, the amount used depends on the viscosity of the solvent and the solubility in the solvent, but is, for example, 0.1 to 15% by weight, preferably 1 to 10% by weight in the spinning solution.

The spinning solution can be produced by mixing the polymer, solvent and, if necessary, additives by a conventionally known method.

When the polymer is PTFE, preferred examples of the spinning solution include the following spinning solution (1).
Spinning liquid (1): Contains 30 to 70% by weight of PTFE, preferably 35 to 60% by weight, contains 0.1 to 10% by weight of a fiber forming agent, preferably 1 to 7% by weight, and has a total of 100% by weight. Spinning solution containing solvent so that

The applied voltage during electrospinning is preferably 1 to 100 kV, more preferably 5 to 50 kV, and even more preferably 10 to 40 kV.

The tip diameter (outer diameter) of the spinning nozzle used for electric field spinning is preferably 0.1 to 2.0 mm, more preferably 0.2 to 1.6 mm.

More specifically, for example, when the spinning liquid (1) is used, the applied voltage is preferably 10 to 50 kV, more preferably 10 to 40 kV, and the tip diameter (outer diameter) of the spinning nozzle. ) Is preferably 0.3 to 1.6 mm.

[Manufacturing method of non-woven fabric or woven fabric]
In order to form a non-woven fabric using the fibers, specifically, for example, a step of manufacturing the fibers by using an electrospinning method and a step of accumulating the fibers in a sheet to form a non-woven fabric are simultaneously performed. This may be performed, or after performing the step of producing the fiber, a step of accumulating the fibers in a sheet shape by a wet method or the like to form a non-woven fabric may be performed.

Examples of the method of forming the non-woven fabric by the wet method include a method of using an aqueous dispersion containing the fibers and depositing (accumulating) the fibers on a mesh to form a sheet (papermaking). ..

The amount of fiber used in this wet method is preferably 0.1 to 10% by weight, more preferably 0.1 to 5% by weight, based on the total amount of the aqueous dispersion. If the fibers are used within this range, water can be efficiently utilized in the step of depositing the fibers, the dispersed state of the fibers is improved, and a uniform wet non-woven fabric can be obtained.

In the aqueous dispersion, a dispersant or an oil agent composed of a cationic, anionic, nonionic or other surfactant, or an antifoaming agent that suppresses the generation of bubbles, etc. are added to improve the dispersed state. One kind or two or more kinds may be added.

In order to form a woven fabric using the fibers, it can be produced by a method including a step of producing the fibers and a step of weaving the obtained fibers into a sheet to form a woven fabric.
As a method for weaving fibers into a sheet, a conventionally known weaving method can be used, and examples thereof include a water jet room, an air jet room, and a rapier room.

When the polymer is PTFE, it is preferable to perform heat treatment after forming a non-woven fabric or a woven fabric. The heat treatment is carried out by heat-treating the obtained non-woven fabric or woven fabric at 200 to 390 ° C. for 30 to 300 minutes. By this heat treatment, the solvent, fiber forming agent and the like remaining on the non-woven fabric or woven fabric can be removed.

As a method for producing the non-woven fabric, a case including a step of producing a fiber made of PTFE by an electric field spinning method will be specifically described as an example. As a method for producing a non-woven fabric made of PTFE fiber, a conventionally known production method can be adopted, and examples thereof include the following methods described in Japanese Patent Application Laid-Open No. 2012-515850.
With the step of providing a spinning solution containing PTFE, a fiber forming agent and a solvent and having a viscosity of at least 50,000 cP;
With the step of spinning the spinning liquid from the nozzle and making it into fibers by electrostatic traction force;
With the step of collecting the fibers on a collector (eg, take-up spool) to form a precursor;
A method comprising a step of forming a non-woven fabric made of PTFE fiber by firing the precursor to remove the solvent and the fiber forming agent.

The basis weight of the non-woven fabric and the woven fabric is preferably 100 g / m ² or less, more preferably 0.1 to 50 g / m ² , and further preferably 0.1 to 20 g / m ² .
The basis weight tends to increase by lengthening the spinning time, increasing the number of spinning nozzles, and the like.

The non-woven fabric and woven fabric are obtained by accumulating or weaving the fibers in a sheet shape, and such non-woven fabric and woven fabric are composed of a single layer or two or more layers having different materials and fiber diameters. It may be any of the above.

[Polarization process]
The porous resin sheet is preferably polarized. By applying the polarization treatment, electric charges can be injected into the sheet. The injected electric charge is concentrated in the pores existing in the porous resin sheet to induce polarization. The internally polarized sheet can take out electric charges through the front and back surfaces of the sheet by applying a compressive load in the sheet thickness direction. That is, charge transfer occurs to an external load (electric circuit) and an electromotive force is obtained.

As the method of the polarization treatment, a conventionally known method can be used, and the method is not particularly limited, and examples thereof include a voltage application process such as a DC voltage application process and an AC voltage application process, and a corona discharge process.

For example, the corona discharge process can be performed using a commercially available device consisting of a high voltage power supply and electrodes.
The discharge conditions may be appropriately selected according to the material and thickness of the porous resin sheet to be used. For example, when the porous resin sheet is a porous resin sheet made of PTFE, a preferable condition is a high voltage power supply. The voltage is −0.1 to -100 kV, more preferably -1 to -20 kV, the current is 0.1 to 100 mA, more preferably 1 to 80 mA, and the distance between the electrodes is 0.1 to 100 cm, more preferably 1 to 10 cm. , The condition that the applied voltage is 0.01 to 10.0 MV / m, more preferably 0.5 to 2.0 MV / m can be mentioned.

In the polarization treatment, the porous resin sheet alone may be polarized, but when a laminate of the porous resin sheet and the conventionally known layer such as an insulating layer is used as the piezoelectric element layer, After forming the laminated body, for example, after laminating an insulating layer, it is preferable to perform a polarization treatment.
This is because the layer laminated on the porous resin sheet plays a role of preventing the electric charge held on the porous resin sheet by the polarization treatment from being electrically connected to the external environment and being attenuated, so that the sensitivity is higher. Because it is considered that the vibration sensor of the above can be obtained, and a new interface capable of holding an electric charge can be formed between the porous resin sheet and the layer laminated on the porous resin sheet. This is because it is considered that the piezoelectricity of the porous resin sheet in the obtained vibration sensor is improved.

<Vibration transmitter>
The vibration transmitter is used by being fixed to the vibrating body, and the size, shape and the like are not particularly limited. The vibration transmitter has a shape or a shape in which, as shown in FIG. 1, a housing space for accommodating the vibration detection laminate is provided between the vibration body fixing portion which is a portion fixed to the vibration body and the vibration body. As in No. 2, it is preferable that the shape has an accommodation space for accommodating the vibration detection laminate. When the piezoelectric element layer 2 is arranged so as to be in contact with the vibration transmitter 3 as shown in FIG. 1, the piezoelectric element layer 2 of the vibration transmitter 3 can detect the vibration of the vibrating body with higher sensitivity. It is preferable that the surface on the side in contact with the vibrating body 5 is substantially parallel to the surface of the vibrating body 5.
Since the vibration transmitter is used by being fixed to the vibrating body, it also has a function as a fastening body for fixing the vibration sensor according to the embodiment of the present invention to the surface of the vibrating body.

The material of the vibration transmitter is not limited as long as it can transmit the vibration from the vibrating body to one surface of the piezoelectric element layer without attenuating it as much as possible, but the vibration from the vibrating body is efficiently transferred to the piezoelectric element. The ratio Z1 / Z2 of the acoustic impedance (Z1) of the material of the vibrating body surface of the part in contact with the vibrating body and the acoustic impedance (Z2) of the material of the vibrating body from the viewpoint of being able to transmit to one surface of the layer. However, a material preferably in the range of 0.2 to 5.0, more preferably 0.4 to 3.0, and even more preferably 0.7 to 1.3 is desirable.
The acoustic impedance Z is obtained by the formula Z = ρ × v from the density ρ calculated by the Archimedes method and the internal transmitted sound velocity v measured by the transmission method.

Examples of the material of the vibration transmitter include aluminum (Z = 17 × 10 ⁶ kg / m ² s), SUS304 (Z = 45 × 10 ⁶ kg / m ² s), and acrylic resin (Z = 3.2 ×). 10 ⁶ kg / m ² s) or the like can be used, but usually, it is preferable that the material has high rigidity with small vibration damping, and it is more preferable that the material is the same as the surface of the vibrating body in contact with the vibration transmitting body. preferable.
An impedance matching layer may be interposed between the surface of the vibrating body and the vibrating body from the viewpoint of efficiently transmitting the vibration from the vibrating body to one surface of the vibration detection laminated body.

The method of fixing the vibration transmitter to the vibrating body is not particularly limited, and examples thereof include conventionally known methods, for example, a method of fixing by an adhesive force or (electrical) magnetic force, and a method of fixing by a fastener, which are necessary. May be combined with these methods.

<Vibrator>
According to the vibration sensor according to the embodiment of the present invention, it is easy to install and handle, and it is possible to reduce the weight and size. Therefore, the surface of the vibrating body is curved or the like in a desired place such as a narrow portion. Even if there is, it can be installed easily. Therefore, the vibrating body to be detected by the vibrating sensor according to the embodiment of the present invention is not particularly limited, and the vibrating body itself does not undergo dimensional deformation (eg, change in the diameter of the pipe). However, vibration can be easily detected.

Examples of the vibrating body include machines including pipes, ground, buildings, vehicles, ships, aircraft, rotating parts, and the like.
Examples of the piping include water supply piping, gas piping, petrochemical plant piping, heat exchanger piping, fuel piping, hydraulic / pneumatic piping, chemical solution piping, food plant piping, and the like. By using the vibration sensor according to the embodiment of the present invention for such a pipe, the sensor also has a role as an abnormality detector for detecting an abnormality such as a leakage of a fluid in the pipe.
Further, examples of the rotating system parts include pumps, compressors, motors, engines, bearings, turbines, wheels and the like. By using the vibration sensor according to the embodiment of the present invention for such a component, the sensor also has a role as an abnormality detector for detecting an abnormality of a rotating system component.

The material of the surface of the vibrating body is the material of the surface of the piping, parts, etc., and examples thereof include metals, ceramics, and polymers (rubber, resin).

According to the vibration sensor according to the embodiment of the present invention, it is easy to install and handle, and it can be easily installed even if the surface of the vibrating body is a curved surface or the like. The place of use is not particularly limited, and examples of the surface shape include a flat surface, a curved surface (cylindrical surface, spherical surface), and an uneven surface.

≪Vibration sensor manufacturing kit≫
The vibration sensor manufacturing kit according to the embodiment of the present invention includes a vibration transmitter, a piezoelectric element, and a vibration absorber used by being fixed to the vibrating body, and the vibration of the vibrating body is caused by the piezoelectric element. The piezoelectric element and the vibration absorber preferably vibrate with the piezoelectric element so that they are suppressed by the vibration absorber on one surface and transmitted by the vibration transmitter on the other surface of the piezoelectric element. It is a kit in which a laminated body with an absorber is arranged and used.
This kit creates a vibration sensor according to an embodiment of the present invention. That is, the vibration transmitter in the kit corresponds to the vibration transmitter in the vibration sensor according to the embodiment of the present invention, and the piezoelectric element in the kit corresponds to the piezoelectric element layer in the vibration sensor according to the embodiment of the present invention. Correspondingly, the vibration absorber in the kit corresponds to the vibration absorbing layer in the vibration sensor according to the embodiment of the present invention.

≪Vibration measurement method≫
In the vibration measurement method according to the embodiment of the present invention, the vibration sensor (including the vibration sensor obtained from the vibration sensor manufacturing kit) according to the embodiment of the present invention is installed on the surface of the vibrating body to form a vibrating body. Detects vibration. Specifically, the presence or absence of vibration, the magnitude of vibration, and the like can be detected.
The installation is not particularly limited as long as the structure of the installed vibrating body with a vibration sensor satisfies the above relationship, and may be installed by the same method as the above-mentioned method of fixing the vibration transmitter. ..

Claims (9)

A vibration transmitter fixed to the vibrating body and
A vibration detection laminate, which is a laminate of a piezoelectric element layer and a vibration absorption layer, is provided.
The vibration absorbing layer is a layer made of gel.
The vibration detection laminate is provided in the accommodation space formed between the vibration transmitter and the vibration body.
The vibration absorbing layer is provided in contact with the vibrating body, and the piezoelectric element layer is provided between the vibration absorbing layer and the vibration transmitting body.
The vibration detection laminate is provided so that the vibration of the vibrating body is suppressed by the vibration absorbing layer on one surface of the piezoelectric element layer and transmitted by the vibration transmitter on the other surface of the piezoelectric element layer. Have, have
A vibration sensor that detects the vibration of a vibrating body. The vibration sensor according to claim 1, wherein the vibration transmissibility of the vibration absorption layer is 1 or less. The vibration sensor according to any one of claims 1 to 2, wherein the piezoelectric element layer includes a porous resin sheet. The piezoelectric element layer contains a non-woven fabric or woven fabric made of fibers.
The vibration sensor according to any one of claims 1 to 3, wherein the fiber is made of a polymer having no dipole due to a molecular and crystal structure. The vibration sensor according to claim 4, wherein the polymer is polytetrafluoroethylene. The ratio Z1 / Z2 of the acoustic impedance (Z1) of the material of the vibrating body surface of the portion in contact with the vibrating body and the acoustic impedance (Z2) of the material of the vibrating body is in the range of 0.2 to 5.0. The vibration sensor according to any one of claims 1 to 5. A vibration measuring method for detecting the vibration of a vibrating body by installing the vibration sensor according to any one of claims 1 to 6 on the surface of the vibrating body. A vibration transmitter that is fixed to the vibrating body and used
Piezoelectric element and
Including a vibration absorber made of gel
The vibration detection laminate is arranged and used in the accommodation space formed between the vibration transmitter and the vibration body.
The vibration absorbing layer is arranged in contact with the vibrating body, and the piezoelectric element layer is arranged and used between the vibration absorbing layer and the vibration transmitting body.
The piezoelectric element and the vibration absorber so that the vibration of the vibrating body is suppressed by the vibration absorber on one surface of the piezoelectric element and transmitted by the vibration transmitter on the other surface of the piezoelectric element. Is placed and used,
Vibration sensor manufacturing kit. A vibration measuring method for detecting the vibration of a vibrating body by installing the vibration sensor obtained from the vibration sensor manufacturing kit according to claim 8 on the surface of the vibrating body.

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