WO2008013049A1

WO2008013049A1 - Strain sensor and strain sensor system

Info

Publication number: WO2008013049A1
Application number: PCT/JP2007/063663
Authority: WO
Inventors: Hiroshi Sugiura; Kouji Michiba; Tatsuaki Sawai; Osamu Muragishi
Original assignee: Kawasaki Jukogyo Kabushiki Kaisha
Priority date: 2006-07-24
Filing date: 2007-07-09
Publication date: 2008-01-31
Also published as: JPWO2008013049A1; JP5004955B2

Abstract

[PROBLEMS] To detect strain generated in a measuring object without an error by a simple and low-cost configuration. [MEANS FOR SOLVING PROBLEMS] A strain sensor (1) is provided with a thin film substrate (2) adhered on an measuring object (10); a pair of strain transmitting pieces (3A, 3B), which are arranged to face each other on the thin film substrate (2) by sandwiching a small gap (G), and each of which is fixed to the thin film substrate (2) on at least one portion; and a sensor foil (4), which is adhered over the pair of strain transmitting pieces (3A, 3B) and has, at a position corresponding to the gap (G), bridge sections (4a, 4b), which have a cross-section area smaller than that of the foil at a position adhered on the strain transmitting pieces (3A, 3B). One strain transmitting piece (3A) of the transmitting pieces has a stress of warping in a direction to be separated from the thin film substrate (2).

Description

Specification

Strain detector and strain detection system

Technical field

[0001] The present invention includes a simple and inexpensive strain detection device that is used by being attached to a measurement object in order to determine whether there is an excessive load by monitoring strain acting on a structure or the like. The present invention relates to a strain detection system.

Background art

[0002] In the maintenance and management of structures and the like, it is important to know whether or not the structures and the like have been damaged during operation so that their functions cannot be sufficiently performed. One method that has been used in the past to estimate the strain in a material is to always measure the generated strain by attaching a strain gauge to the measurement object. Since this method requires the use of precise measuring devices such as power supply devices and converters, it is not suitable for measuring a large number of parts at once. Therefore, it is difficult to apply this method to large structures, etc. so that the overall history of strain history can be ascertained.

[0003] Japanese Patent Application Laid-Open No. 9-005175 discloses a stress measurement sensor for grasping the magnitude of stress received by a structure. In this stress measurement sensor, both ends of a wire made of a material that breaks with a smaller strain than the object to be measured are fixed to the object to be measured, and the presence / absence of the fracture of the wire is determined by the stress acting on the object to be measured. It is used to determine whether or not the power is greater than the value.

[0004] This stress measurement sensor is formed by fixing a fixing base to a thin film serving as a base and fixing both ends of the wire to the fixing base with an adhesive or the like. For the wire, a material with a low breaking strain (for example, nickel, titanium, carbon steel, etc.) is selected. For the fixing base, a non-conductive polymer material, a ceramic material, a non-ferrous metal material, or the like is selected. Since this stress measurement sensor is formed by adhering a detection wire to a base fixed on a thin film to be attached to a measurement object, it is difficult to ensure the reproducibility of the shape and dimensions in the manufacturing process. It is difficult to make reliable measurements. Especially when using a small sensor, the detection wire must be moderately cautious when observing breakage of the detection plate. [0005] On the other hand, Japanese Patent Application Laid-Open No. 2001-281120 discloses a crack type fatigue sensor in which a fracture piece having a crack propagation portion is formed at the center of a metal foil substrate. In this crack type fatigue sensor, a slit with a sharp tip is also formed at the crack propagation part, and the side end force is also formed, and a crack occurs at the tip of the slit depending on the degree of repeated stress generated on the measurement object, and the crack progresses.

Disclosure of the invention

Problems to be solved by the invention

[0006] However, various members such as structures and transporting machines are manufactured by various methods such as welding, machining, extrusion molding, and forging. If we try to estimate, the relationship with the crack of the fatigue sensor changes depending on the object to be measured, so complicated calculations are required to obtain sufficiently correct results. As described above, there is a problem that advanced knowledge and skill are required to properly use the disclosed fatigue sensor. Therefore, it is used for easy maintenance and management of equipment and structures, and it is affixed to the surface of the structure like a strain gauge to monitor the stress and check that there was an excessive load. The development of a simple and inexpensive sensor that can be reliably checked is required.

[0007] Therefore, an object of the present invention is to make it possible to detect a distortion generated in a measurement object without error with a simple and inexpensive configuration.

Means for solving the problem

[0008] The present invention has been made in view of the circumstances as described above, and a strain detection apparatus according to the present invention includes a thin film substrate that is attached to a measurement object and is distorted together with the measurement object, and the thin film substrate. A pair of strain transmitting pieces, which are opposed to each other across a small gap and fixed to the thin film substrate at at least one force point, are pasted on the pair of strain transmitting pieces, and the strain is placed at a position corresponding to the gap. A sectional area smaller than the position affixed to the transmission piece, and a sensor foil having a bridge portion, and one of the pair of strain transmission pieces has a stress that tends to warp in a direction in which the thin film substrate force is also separated. It is characterized by having The stress is an inherent stress given in advance to the strain transmission piece, and the stress transmission piece is constrained to each other via a sensor foil. The distortion caused by is something that does not appear.

[0009] According to the above configuration, the sensor foil is stuck across the pair of strain transmission pieces, and the bridge portion having a small cross-sectional area is provided between the pair of strain transmission pieces. The stress when the strain is generated concentrates on the bridge portion of the sensor foil. In other words, this strain detector has a strain expansion function. The sensor foil has a predetermined breaking elongation characteristic, and when the local strain of the bridge portion exceeds the breaking elongation, the bridge portion, which is the minimum cross-sectional portion, breaks. When the bridge part breaks, it can be estimated that a strain greater than a predetermined strain determined from the breaking strength of the sensor foil and the concentration of strain has occurred in the measurement target site.

[0010] And, since the sensor foil is integrally connected until it breaks, if the bridge portion breaks at the position of the flat force gap, the potential stress inherent in one strain transmitting piece becomes obvious. Thus, the strain transmitting piece, along with the broken end of the sensor foil, warps in a direction away from the thin film substrate, and does not return. For this reason, the operator can know the breakage of the sensor foil easily and accurately without misunderstanding by visually observing the warping of the broken end of the sensor foil.

[0011] Furthermore, since a strain detection sensor, which is a combination of a strain transmission piece and a sensor foil that determines the sensitivity of the strain detection device, is formed in advance on the thin film substrate, the strain detection device is attached to the measurement object. In addition, the breaking strain of the sensor foil does not change, and the sensor foil can be used as a sensor having sensitivity as designed, improving reliability.

[0012] Further, the strain detection device is adjusted so that the sensor foil is broken by the strain of the measurement object that occurs when the stress at the application position reaches a predetermined value when it is applied to the measurement object. There should be. While the relationship between strain and load changes according to the object to be measured, the sensor foil breakage is controlled by the strain of the thin film substrate affixed to the object to be measured. Varies with load. Therefore, it is preferable to adjust the sensitivity based on the object to be measured and the purpose of the measurement so that the correct damage strength can be detected.

[0013] The greater the difference in thickness between the strain transmitting piece and the sensor foil and the greater the difference in rigidity between the two, the greater the strain sensitivity. Therefore, the difference in thickness is adjusted as much as possible to ensure accuracy. The measurement range of the maximum strain value can be adjusted. In addition, the strain that appears on the sensor foil due to the occurrence of strain on the object to be measured increases as the distance between the bonding positions of the pair of strain transmitting pieces to the thin film substrate increases. Sensitivity can be adjusted.

[0014] When the sensor foil is formed by etching or the electroplating method, the narrowed portion of the sensor foil can also be accurately formed. In addition, the thickness of the sensor foil can be accurately controlled by a two-stage electrical method. The thin film substrate may be formed of stainless steel, and the sensor foil may be formed of rolled copper or electrolytic copper. The thin film substrate may be formed of invar, and the sensor foil may be formed of nickel. When the sensor foil has a smaller elongation at break, it can constitute a strain detection device that detects even a small strain of the measurement object. In addition, it is preferable to select a material whose characteristics are well known and easy to manufacture. Therefore, it is preferable to use a high-strength copper foil for the sensor foil. Nickel is sufficiently hard and is suitable for sensor foil because it has accumulated information and technology using fatigue sensors. Note that the back side of the thin film substrate should be a rough surface by etching a number of shallow thin wires, etc., and the adhesion should be improved when it is fixed to the surface of the object to be measured with an adhesive.

[0015] The sensor foil may include a plurality of the bridge portions in a portion crossing the gap.

[0016] According to the above configuration, since a plurality of bridge portions serving as fracture portions are provided, the reliability is improved.

[0017] The strain transmitting piece is subjected to the stress, that is, inherently, by heat input to a portion between the position of the gap and the position fixed to the thin film substrate so as not to be bonded to the thin film substrate. Stress may be applied.

[0018] Specifically, the strain transmitting piece is melt-bonded at a portion where the strain transmitting piece is fixed to the thin film substrate by being heated by a local heating device from the thin film substrate side. The stress is applied to the position between the position of the gap and the position fixed to the thin film substrate by heat input to the extent that the strain transmission piece does not join the thin film substrate with a local heating device. Anyway.

[0019] The strain transmission piece and the sensor foil are made of metal, and the strain transmission piece and the sensor foil. An insulating adhesive layer is interposed between the sensor foil and it's okay!

[0020] According to the above configuration, it is possible to detect the presence or absence of breakage by connecting an ammeter or a resistance meter to both sides of the sensor foil across the bridging bridge portion. Since an insulating adhesive layer (for example, a polyimide film) is provided between the strain transmitting piece and the sensor foil, even if the opposing strain transmitting pieces come into contact with each other, the respective strain transmitting pieces are interposed. There is no accidental conduction.

[0021] Instead of detecting the continuity Z non-conduction by applying an ammeter or resistance meter probe to the sensor foil at the site, information on the presence or absence of breakage of the bridge portion can be obtained by connecting a wire to the sensor foil. May be receivable. Needless to say, data transmission can also be performed by wireless communication. When using wireless communication, the power supply must be attached to the strain detection device. When using wireless, the power supply is an independent power supply that uses dry batteries or solar cells and does not require wiring work.

[0022] The strain transmitting piece is integrally connected to a part of the strain transmitting piece, surrounds the strain transmitting piece, and the reinforcing frame having the same material force as that of the strain transmitting piece is removed. It may be formed by. For example, the reinforcing frame and the strain transmitting piece may be formed from a single plate by etching or electroplating.

[0023] Between the strain transmitting piece and the reinforcing frame, a folding line is provided in which elongated holes partitioned by a thin connecting portion are arranged, and the reinforcing frame is removed by folding the connecting portion. It may be.

[0024] According to the above configuration, when the strain detection device is attached to the measurement object, the connecting frame can be broken and the reinforcing frame can be removed, which facilitates handling before installation on the measurement object. In addition, it is possible to prevent damage and the like during product transportation.

[0025] A plurality of strain detection sensors, which are a combination of the pair of strain transmission pieces and the sensor foil, are arranged on the thin film substrate, and one of the pair of strain transmission pieces to the thin film substrate. A distance between the fixed position and the fixed position of the pair of strain transmitting pieces to the other thin film substrate may be different for each of the plurality of strain detection sensors.

[0026] According to the above configuration, some of the plurality of strain detection sensors are broken, When the remaining force does not break, it can be estimated that a stress between the detected stress of the broken strain sensor and the detected stress of the strain sensor that did not break has occurred in the measurement object. An approximate value of the stress history of the object can be estimated.

In this case, the plurality of strain detection sensors may be arranged such that detection axes that coincide with the direction in which the pair of strain transmission pieces are aligned are substantially parallel to each other.

[0028] According to the above configuration, of two or more sets of strain detection sensors having different stress sensitivities, which strain detection sensor foil is broken and which strain detection sensor foil is not broken is checked. By doing so, it is possible to estimate the range of the strain value generated in the measurement object.

[0029] A strain detection sensor force that is a combination of the pair of strain transmitting pieces and the sensor foil. A plurality of strain detecting sensors are arranged on the thin film substrate, and one of the pair of strain transmitting pieces is fixed to the thin film substrate. The distance between the fixed position of the pair of strain transmission pieces to the other thin film substrate may be the same among the plurality of strain detection sensors.

[0030] In that case, the plurality of strain detection sensors may be arranged such that detection axes that coincide with the direction in which the pair of strain transmission pieces are aligned are substantially parallel.

[0031] The detection accuracy of the strain detection device is based on the fracture characteristics of the material, and it is impossible to avoid variations in detection accuracy due to material variations and manufacturing variations. Therefore, the detection accuracy can be improved by using a plurality of strain detection sensors of the same type together as in the above configuration. When multiple strain detection sensors are used, the variation in detection accuracy is the root mean square of the accuracy variation of each strain detection sensor, so reliability is improved by using multiple strain detection sensors.

[0032] Further, the plurality of strain detection sensors may be arranged such that detection axes that coincide with an arrangement direction of the pair of strain transmission pieces intersect each other.

[0033] The strain detection device needs to be installed with the detection axis aligned in the direction in which the largest strain is generated in the measurement object. However, in reality, it may be difficult to know in advance the direction of the maximum stress axis, such as the direction of stress generation during an earthquake or the direction of stress in a complex structure. When applied to such measurement objects, multiple strain detection sensors are used. By using strain detection devices that are arranged so that the detection axes of the sensors point in different directions (for example, radially), it is possible to detect without overlooking the maximum strain generated in the measurement object. it can.

[0034] A strain detection sensor, which is a combination of the pair of strain transmission pieces and the sensor foil, may be surrounded by a protective cover.

[0035] According to the above configuration, the weather resistance and corrosion resistance of the sensor can be maintained even when monitoring by the strain detection device is performed for a long period of time. The protective cover is a lid made of grease material, matt steel plate, painted steel plate, etc., and covers the entire strain detection sensor so that the operation of the detection sensor is not hindered, and the hem part is bonded or welded with grease. It may be fixed to the thin film substrate with airtightness by screwing or screwing. When connecting one end of an electric wire to an electrode terminal to be described later, the other end of the electric wire should be pulled out of the protective cover.

[0036] A grease coating may be applied to the pair of strain transmitting pieces and the strain detection sensor of the sensor foil.

[0037] According to the configuration, as described above, the weather resistance and corrosion resistance of the sensor can be maintained even when monitoring by the strain detection device is performed over a long period of time. In order not to interfere with the sensitivity of the sensor, the resin coating should not be so strong and strong that it does not interfere with the operation of the strain detection sensor. When the hardness of the resin coating is high, it is preferable to form a space under the coating so as not to prevent the sensor foil from breaking.

[0038] The sensor foil may have a pair of electrode terminals which have a conductive force and are conducted through the bridge portion.

[0039] According to the above configuration, it is possible to detect breakage or deformation of the sensor foil by electrically inspecting the resistance change of the sensor foil between the pair of electrode terminals. Since the strain transmitting piece is stressed as described above, it is possible to reliably prevent a detection error caused by contact between the broken ends of the sensor foil.

[0040] The sensor foil may include a plurality of the bridge portions at a portion crossing the gap, and the electrode terminals may be gathered on one side of the pair of strain transmitting pieces.

[0041] According to the above configuration, for example, when the two bridge portions are configured to straddle the gap, the positions of the electrode terminals are combined on one side, and thus an efficient circuit configuration can be realized. wear.

[0042] The electrode terminal may be provided on the opposite side of the bridge portion across the bonding position of the strain transmitting piece and the thin film substrate.

[0043] According to the above configuration, since there is no electrode terminal in the detection region between the position where the strain transmission piece is bonded to the thin film substrate and the position of the bridge portion, an electric wire or the like is connected to the electrode terminal. It is possible to prevent the stress at the time from affecting the strain change.

[0044] The sensor foil has a plurality of the bridge portions at a portion crossing the gap, and the electrode terminal is formed at an end portion of the sensor foils connected in series. May be.

[0045] According to the above configuration, a pair of electrode terminals corresponding to the plurality of bridge portions is sufficient, and the pair of electrode terminals is in a non-conducting state. It can be detected that one breaks.

[0046] Further, a strain detection system according to the present invention includes the above-described strain detection device, a detection circuit that is connected to the electrode terminal of the strain detection device and detects breakage of the bridge portion, and the detection circuit. A transmission circuit that transmits a detection signal when a break is detected, and a reception device that receives the detection signal of the transmission circuit force are provided.

[0047] According to the above configuration, when the strain in the measurement object exceeds a predetermined value, the sensor foil of the strain detection device is broken, and the disconnection between the electrode terminals is detected by the detection circuit. In response to this detection, the transmission circuit transmits a detection signal to the receiving device. Therefore, even if the operator does not look at the sensor foil, the receiving device can know that the sensor foil is broken.

[0048] In addition, the strain detection device can use any material as a measurement object, and is attached to the surface of the measurement object by an adhesive, welding, or the like. Therefore, for example, a strain detection device is affixed to the stress generating part in the steel materials of structures, transportation equipment, buildings, machinery, such as cranes, bridges, railway vehicles, airplanes, automobiles, construction steel frames, reinforcing bars, rotating machinery, etc. Then, the detection signal generated when the load or displacement acting on the part to be measured exceeds a predetermined value is converted into an electrical signal and transmitted to the receiving device, so that the occurrence of an abnormal load condition is monitored by the receiving device. be able to. The strain detection device can be applied to stress generating members other than steel such as non-ferrous materials, polymer materials, composite materials, concrete, asphalt, and wood. A normal load can also be detected.

[0049] The transmission circuit may transmit the detection signal wirelessly to the receiving device.

[0050] According to the above configuration, the transmission circuit takes in the detection signal from the detection circuit, converts it into a radio wave signal, and transmits it wirelessly. The receiving device receives the radio signal and detects the breakage of the sensor foil. If the transmitter circuit and receiver are separated and the radio signal is strong, the signal is received by a receiver installed in a central control room at a remote location, and whether or not the measurement object has received an excessive load. Remote monitoring is also possible. In addition, since no connection is required between the transmitting circuit and the receiving device, it can also be applied to the case where the object to be measured with a force is a moving body if construction is easy.

[0051] An independent power supply for supplying power to the detection circuit and the transmission circuit may be further provided.

[0052] According to the above configuration, the detection circuit and the transmission circuit are used by being connected to the electrode terminal of the strain detection device, and therefore are installed close to the measurement object. Therefore, in order to take advantage of the use without connecting the transmission circuit and the reception device, it is preferable that the power source for supplying power to the detection circuit and the transmission circuit is an independent power source that does not depend on the power supply line such as a dry cell or a solar cell.

[0053] The detection circuit and the transmission circuit are part of an IC tag, and the IC tag includes a storage unit that stores information on whether or not a break is detected by the detection circuit, and the reception device includes: The IC tag reader may also be capable of reading information from the storage unit of the IC tag.

[0054] According to the above configuration, the IC tag is attached to the strain detection device in a state where the IC tag terminal is connected to the electrode terminal of the sensor foil, and the operator attaches the IC tag reading device to the IC tag. The sensor foil break information is transmitted to the IC tag reader as well. Note that it is preferable to use a non-power supply type that uses non-contact power supply when an IC tag is read by an IC tag reader, because an independent power supply is unnecessary.

[0055] The strain detection device includes a plurality of strain detection sensors of the pair of strain transmission pieces and the sensor foil on the thin film substrate, and one of the pair of strain transmission pieces is fixed to the thin film substrate. And the distance between the fixed position of the pair of strain transmission pieces to the other thin film substrate differs for each of the plurality of strain detection sensors, and the measurement A state sensor that detects a state other than the strain of the object, and a determination circuit that selects one of the plurality of strain detection sensors to be used for strain detection based on the output of the state sensor. .

[0056] The state quantity of the measurement object detected by the state sensor, that is, the state quantity that affects the stress condition other than strain, includes the temperature of the measurement object, the acceleration of the measurement object, angular velocity, vibration, There are things related to movement such as displacement.

[0057] According to the above configuration, for example, when the strength of the measurement object changes extremely with temperature, a strain detection device in which a plurality of strain detection sensors having different fracture strain values are arranged on the thin film substrate; By adding a temperature sensor, the judgment circuit selects a strain detection sensor with an appropriate breaking strain value according to the output of the temperature sensor for strain detection, so that detection errors due to large temperature changes can be prevented. it can. Specifically, if the temperature of the object to be measured can withstand some strain at room temperature even if it is damaged by a slight strain at extremely low temperatures, the sensor foil of a highly sensitive strain detection sensor when the temperature sensor indicates room temperature If the sensor foil of the strain detection sensor for room temperature does not break even if it breaks, it may be determined that there is no overload. On the other hand, when the temperature sensor shows a very low temperature, the fracture state in the strain detection sensor has a sensor foil that breaks with a slight strain.

If you decide overload,

[0058] An alarm device may be further provided that generates an alarm when the detection circuit detects a break of the bridge portion.

[0059] When this alarm device receives a detection signal that the bridge portion of the sensor foil is broken, it generates an electrical signal such as generation or interruption of current, performs color display, or outputs sound. It is preferable to generate radio waves. For example, if a strain sensing device is used that is adjusted to operate before a mechanical device such as a crane reaches a limit load, if the sensor is activated during operation, the mechanical device is stopped immediately. Safety can be ensured. Instead of making an emergency stop directly due to the operation of the sensor, an alarm may be issued to complain that an emergency stop is necessary.

Brief Description of Drawings

FIG. 1 is a plan view of a strain detection device according to a first embodiment of the present invention. 2 is a cross-sectional view taken along line II-II in FIG.

FIG. 3 is a bottom view of the strain detection device shown in FIG. 1.

FIG. 4 is an enlarged plan view of a bridge portion of the strain detection device shown in FIG.

FIG. 5 is a cross-sectional view taken along line V—V in FIG.

6 is a plan view of the strain detection device shown in FIG. 1 before removal of the reinforcing frame.

FIG. 7B is an explanatory diagram regarding the application of stress in the strain detection apparatus shown in FIG.

[7]] It is an explanatory view related to the application of stress in the modified example.

[7C] It is an explanatory view related to the application of stress in still another modified example.

FIG. 8 is a perspective view for explaining an excessive strain detection mechanism of the strain detection device shown in FIG. 1.

[9] FIG. 9 is a perspective view of a strain detection device according to a second embodiment of the present invention.

FIG. 10 is a perspective view of the strain detection device shown in FIG. 9 when the sensor foil is broken. [11] FIG. 11 is a perspective view of a strain sensing device according to a third embodiment of the present invention.

FIG. 12 is a perspective view of the strain detection device shown in FIG. 11 when the sensor foil is broken. 13] A perspective view of a strain sensing device according to a fourth embodiment of the present invention.

FIG. 14 is a perspective view of the strain detection device shown in FIG. 13 when the sensor foil is broken. [15] FIG. 15 is a plan view of a strain sensing device according to a fifth embodiment of the present invention.

16] A plan view of a strain sensing device according to a sixth embodiment of the present invention.

[17] FIG. 17 is an explanatory diagram of a method for specifying a detected stress range using the strain detection apparatus shown in FIG.

圆 18] It is explanatory drawing of the distortion | strain detector based on 7th Embodiment of this invention.

圆 19] It is explanatory drawing of the distortion | strain detector based on 8th Embodiment of this invention.

[20] FIG. 20 is a plan view of a strain sensing device according to a ninth embodiment of the present invention.

FIG. 21 is a block diagram of a strain detection system according to a tenth embodiment of the present invention.

FIG. 22 is a block diagram of a strain detection system according to an eleventh embodiment of the present invention.

FIG. 23 is a block diagram of a strain detection system according to a twelfth embodiment of the present invention.

FIG. 24 is a block diagram of a strain detection system according to a thirteenth embodiment of the present invention.

FIG. 25 is a block diagram of a strain detection system according to a fourteenth embodiment of the present invention. FIG. 26 is an explanatory diagram for explaining functions of the strain detection system shown in FIG. 25.

FIG. 27 is a schematic view showing a first usage example of the strain detection apparatus of the present invention.

FIG. 28 is a schematic view showing a second usage example of the strain detection apparatus of the present invention.

FIG. 29 is a schematic view showing a third usage example of the strain detection apparatus of the present invention.

FIG. 30 is a schematic view showing a fourth usage example of the strain detection apparatus of the present invention.

FIG. 31 is a plan view of a strain detection device of a modified example in which shear stress is detected for application to the rotating shaft and the like shown in FIG. 30.

FIG. 32 is a schematic view showing a fifth usage example of the strain detection apparatus of the present invention.

FIG. 33 is a plan view of the strain detection unit used in FIG. 32.

FIG. 34 is a schematic view showing a sixth usage example of the strain detection apparatus of the present invention.

FIG. 35A is a side view of the sensor plate shown in FIG. 34.

FIG. 35B is a plan view of the sensor plate shown in FIG. 34.

FIG. 36 is a schematic view showing a seventh example of use of the strain detection apparatus of the present invention.

FIG. 37 is an enlarged view of the main part of FIG.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.

[0062] (First embodiment)

FIG. 1 is a plan view of a strain sensing device 1 according to the first embodiment of the present invention. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. As shown in FIGS. 1 and 2, the strain detection device 1 includes a thin film substrate 2 attached to the measurement object 10 and a pair of strain transmission pieces placed on the thin film substrate 2 with a small gap G interposed therebetween. 3A and 3B, and a sensor foil 4 stuck on the pair of strain transmitting pieces 3A and 3B. The strain transmitting pieces 3A and 3B and the sensor foil 4 are bonded and fixed to each other through an insulating adhesive layer 5. That is, a three-layer thin film structure is formed by the strain transmitting pieces 3A and 3B, the insulating adhesive layer 5 and the sensor foil 4, and one unit of the three-layer thin film structure is referred to as a strain detection sensor 6.

[0063] The thin film substrate 2 is adhered to the surface of the measurement object 10 with an adhesive, and the distortion of the measurement object 10 is faithfully transmitted to the strain transmitting pieces 3A and 3B. The strain transmission pieces 3A and 3B are made of a metal thin film. The pair of strain transmission pieces 3A and 3B are separated by a very narrow gap G. Spot welds Swl and Sw2 joined to the thin film substrate 2 are formed at the other end where the forces are matched and the gap G force is also separated. The spot welds Swl and Sw2 are formed by performing side force spot welding of the thin film substrate 2.

[0064] The strain transmitting pieces 3A and 3B are not restrained by the thin film substrate 2 except for the spot welds Swl and Sw2. Thus, when the strain detection device 1 is attached to the measurement object 10, the measurement object generated between the spot welded part Sw1 of one strain transmission piece 3A and the spot welded part Sw2 of the other strain transmission piece 3B. Ten strains are measured. That is, the detection region of the strain detection device 1 corresponds to the length L between the spot welds Swl and Sw2. Therefore, the detection area can be adjusted by changing the position of the spot welds Swl and Sw2.

[0065] The sensor foil 4 has electrode terminals 4e and 4f formed on the strain transmission piece 3B via thin connecting portions 4c and 4d at end portions away from the bridge portions 4a and 4b. The connecting portions 4c and 4d are provided so that heat does not adversely affect the bridge portions 4a and 4b when an electric wire is soldered to the electrode terminals 4e and 4f. In addition, when the wires are soldered to the electrode terminals 4e and 4f, the electrode terminals 4e and 4f are located outside the detection area of the length L (see Fig. 4) so that the stress transmitted through the wires does not adversely affect the measurement results. 1 is preferably provided on the right side of spot welded part Sw2.

FIG. 3 is a bottom view of the strain detection device 1 shown in FIG. As shown in Fig. 3, the thin film substrate 2 is bonded to the back side by forming a number of thin wires 7 that are shallow recesses perpendicular to the detection axis that coincides with the alignment direction (tensile direction) of the strain transmission pieces 3A and 3B. An uneven surface is formed. The uneven surface for bonding improves the adhesion of the strain detector 1 to the measurement object 10.

FIG. 4 is an enlarged plan view of the bridge portions 4a and 4b of the strain detection device 1 shown in FIG. Fig. 5 is a cross-sectional view taken along line V-V in Fig. 4. As shown in Figs. 4 and 5, the sensor foil 4 is a metal thin film that is thinner than the strain transfer pieces 3A and 3B, and the bridge portions 4a and 4b are formed at positions corresponding to the gaps G of the strain transfer pieces 3A and 3B. Has been. In the bridge portions 4a and 4b, stress concentrates corresponding to the cross-sectional area ratio between the strain transmitting pieces 3A and 3B and the bridge portions 4a and 4b, so that the strain generated in the measurement object 10 expands and the bridge portion 4a , 4b has the effect of gathering. In addition, Blitz The narrow portion d with a narrower width is formed in the flange portions 4a and 4b, and the strain generated in the detection area of the measurement object 10 is concentrated on the narrow portion d to increase the strain. Have

[0068] The strain expansion rate depends on the material of the sensor foil 4 'shape, the material of the strain transmission 3A, 3B', the shape, and the length L of the detection region. Therefore, by adjusting these parameters, the strain expansion rate can be selected as appropriate, and the breaking strain of the strain detector 1 corresponding to the strain value of the measurement object 10 can be determined.

[0069] Further, the thickness' shape, gap G amount, etc. of each thin film are appropriately designed according to the strain to be detected of the measurement object. Actually, for example, the thicknesses of the strain transmitting pieces 3A and 3B, the insulating adhesive layer 5 and the sensor foil 4 are 10 μm to several 100 μm, respectively, which is convenient for application to many measurement points. The gap G amount can also be adjusted according to the measurement conditions, and values of several tens of meters to several millimeters are used. Further, the strain transmission pieces 3A and 3B may be made of invar, and the sensor foil 4 may be made of nickel. Regarding the characteristics and manufacturing method of nickel, it is possible to utilize the technology accumulated through the manufacture and use of fatigue sensors.

[0070] The strain detector 1 can be formed by an etching method. For example, the strain detection device 1 is made by bonding a polyimide film with a thickness of 35 m to be the insulating adhesive layer 5 on a stainless steel (SUS304) thin film with a thickness of 100 m to be the strain transmission pieces 3A and 3B. A three-layer structure to be the strain detection sensor 6 is formed by adhering a 50 m thick copper foil to be the sensor foil 4. Such a three-layer structure is similar to that used for hard disk drives and can also be supplied from the factory. The stainless steel thin film and polyimide film of this three-layer structure are etched, for example, strain transmission pieces 3A and 3B with a gap of 140 m, a width of 6 mm and a total length of 46 mm, and a reinforcement frame 8 (described later). 6) and the copper foil is etched from the opposite side to form the shape of the sensor foil 4 including the bridge portions 4a and 4b and the electrode terminals 4e and 4f.

FIG. 6 is a plan view before removal of the reinforcing frame 8 of the strain detection device 1 shown in FIG. As shown in Fig. 6, the reinforcement frame 8 is made of the same thickness and the same material as the strain transmission pieces 3A and 3B, and is connected correctly to the strain transmission pieces 3A and 3B, which may be separated. Maintain the positional relationship, and protect the bridge parts 4a and 4b of the sensor foil 4 before applying to the measurement object 10. It has a function. Further, the reinforcing frame 8 can be used as a fixing allowance when the strain transmitting pieces 3A and 3B are fixed to the thin film substrate 2 by spot welding or the like. In addition, the reinforcing frame 8 can be provided with a marker M for spot welding. The reinforcing frame 8 is a force formed by surrounding the strain transmission pieces 3A and 3B. Between the strain transmission pieces 3A and 3B, elongated holes H separated by a thin connecting portion 9 are arranged to form a crease line. After the detection device 1 is attached to the measurement object 10, the connecting portion 9 is broken and the reinforcing frame 8 is removed, and only the inner strain detection device 1 is attached to the measurement object 10 with an adhesive.

[0072] In that case, it is preferable that the reinforcing frame 8 and the strain transmitting pieces 3A and 3B have the same material force. In this case, the reinforcing frame 8 and the strain transmitting pieces 3A and 3B are simultaneously formed by etching. Can be formed. The sensor foil 4 may be directly formed on the strain transmission pieces 3A and 3B by an electric method. Since the shape reproducibility of the electroplating method is extremely high, the strain detection device 1 formed by the electroplating method can obtain an accurate measurement result. The shape of the sensor foil 4 can also be formed by die cutting.

[0073] Furthermore, by connecting the surface of the strain transmission piece 3A, 3B side of the strain detection sensor 6 of the three-layer structure to the thin film substrate 2, the strain detection device 1 is easily handled and the strain detection device 1 is measured. It can be easily applied to the object 10 and the reproducibility of the measurement can be improved. When the thin film substrate 2 is formed of the same metal as the strain transmission pieces 3A and 3B, the strain transmission pieces 3A and 3B and the thin film substrate 2 can be firmly bonded by spot welding. The thin film substrate 2 may be formed of resin.

[0074] The strain transmitting pieces 3A and 3B are fixed to the thin film substrate 2 by several spot welds Swl and Sw2, which are arranged perpendicularly to the strain direction, for example, at one force point, and the length L of the detection region is L. Is decided. Since the thin film substrate 2 is firmly attached to the surface of the measurement object 10, the spot welds Swl and Sw2 of the strain transmitting pieces 3A and 3B can be substantially fixed to the measurement object 10.

[0075] The elongation δ generated in the detection region of length L due to the extension of the measurement object 10 is distributed to the strain transmission pieces 3Α, 3Β and the sensor foil 4 of the strain detection device 1. The distribution rate is influenced by the Young's modulus 材料 of the material, but it is greatly influenced by the stress concentration related to the cross-sectional area 部品 of the part, and most of the elongation δ generated in the detection region of length L is at the position of the gap G. A bridge 4a, 4b Distributed to sensor foil 4.

[0076] E is the Young's modulus of sensor foil 4, A is the average cross-sectional area of bridges 4a and 4b, E is the Young's modulus of strain transfer pieces 3A and 3B, and A is the gap of sensor foil 4. Elongation at G

twenty two

Δ, and the elongation in the detection area of the two strain transmission pieces 3Α and 3 is δ,

1 2 From the balance condition, the relationship between the strain of the measuring object 10 and the strain ε of the sensor foil 4 is obtained. Ε Ζ ε = (δ ZG) Z ((S + δ) / L)

1 1 1 2

= Α Χ Ε X L / (A Χ Ε X L + A Χ Ε X G)

2 2 1 1 2 2

It becomes.

[0077] For example, assuming that the strain transmission pieces 3A and 3B are made of stainless steel foil with Young's modulus of 168GPa and sensor foil 4 with copper foil with Young's modulus of 1 lOGPa, the detection area length L is 40mm and the gap G is Measured when the width is 0.14 mm, the cross-sectional area of the strain transmitting pieces 3A and 3B is 0.6 mm ² , and the average cross-sectional area of the two bridge parts 4a and 4b of the sensor foil 4 is 0.009 mm ² The ratio ε / ε of the strain ε in the bridge portions 4a and 4b to the strain ε in the object 10, that is, the strain expansion ratio is about 81 times. When the narrow width portion d is formed on the sensor foil 4, the substantial length of the bridge portions 4a and 4b is further shortened, and the strain ε in the bridge portions 4a and 4b is larger than the strain ε of the measurement object 10. Thus, the sensitivity as a sensor is improved.

[0078] The strain ε at the bridge portions 4a and 4b of the sensor foil 4 is the breaking strain ε of the sensor foil 4.

If it exceeds 1 f, sensor foil 4 will break. When the sensor foil 4 is broken, it can be said that the strain ε of the measuring object 10 corresponding to the fracture strain ε of the sensor foil 4 is exceeded. Fracture f

Ε is the material of the sensor foil 4, the shape and size of the bridge parts 4a and 4b, the stress intensity factor K, the turtle f

Since it varies depending on the crack initiation conditions, etc., it is also possible to measure f by adjusting the fracture strain ε.

Can be adapted to meet certain conditions.

[0079] Since the gap G between the strain transmitting pieces 3A and 3B is small, it is difficult to visually determine the fracture state of the bridge portions 4a and 4b simply by cutting the bridge portions 4a and 4b of the sensor foil 4. It is possible. In addition, if the ends of the broken bridge portions 4a and 4b are close to each other, it may be possible that a detection error occurs in the energization tester due to contact with each other. Therefore, in the strain detection device 1 of the present invention, a potential stress that tends to warp outward (in a direction away from the thin film substrate 2) is applied to one strain transmission piece 3A. As a result, when the bridge portions 4a and 4b are broken, the end portion on the gap G side of the strain transmitting piece 3A is lifted from the thin film substrate 2, so that the broken state can be detected easily and reliably. Such potential stress is applied, for example, by applying a spot welder (local heating device) to the strain transmission piece 3A on the upper side (sensor foil 4 side) between the bridge portions 4a and 4b and the spot welded portion Swl. Thus, it can be imparted by forming a heat input portion Sh that has input heat to the thin film substrate 2 so as not to be welded. That is, when heat is applied from the upper force of the strain transmission piece 3A, a thermal strain that tends to shrink is generated in the heat input portion Sh, and the strain transmission piece 3A tries to warp upward. Since the foil 4 is coupled to the other strain transmission piece 3B and thus is prevented from being deformed and held in a flat state, the stress is inherent in the strain transmission piece 3A.

[0081] If the bridge portions 4a and 4b of the sensor foil 4 are broken, this stress becomes obvious, and the strain transmitting pieces 3A and 3B are bent near the heat input portion Sh, and the gap G side end of the strain transmitting piece 3A The part is deformed so as to float from the thin film substrate 2. In addition, when forming spot welds Swl and Sw2, a stress that tends to bend in the direction of the heat input surface is generated in the same manner, so that a moderate amount of warping is also achieved with the heat input for welding. Obtainable. The amount of heat input at the heat input portion Sh should not be so large that the strain transmission piece 3A and the thin film substrate 2 are welded together. When the strain transmission piece 3A and the thin film substrate 2 are joined in the middle, the sensor function is also impaired. Further, the amount of warping of the strain transmitting piece 3A is sufficient if the broken bridge portions 4a and 4b do not recover and the person can easily visually recognize the fracture, and need not be too large.

FIG. 7A is an explanatory diagram relating to the application of stress in the strain detection device 1 shown in FIG. As shown in FIG. 7A, the spot welded portion Sw for joining the strain transmitting pieces 3A, 3B and the thin film substrate 2 is formed by applying a spot welder from the back side (lower side) of the thin film substrate 2. On the other hand, the heat input portion Sh for warping is formed by applying a spot welder from the upper side of the strain transmitting piece 3A. Then, the strain transmitting piece 3A warps only by an appropriate amount on the gap G side from the position of the heat input portion Sh. FIG. 7B is an explanatory diagram relating to the application of stress in a modification. As shown in Fig. 7B, when the strain transmission piece 3A where the heat input part Sh for warping is formed is welded to the thin film substrate 2, heat is applied to the strain transmission piece 3A from the upper side (sensor foil 4 side). The amount of warping can be increased by applying a greater stress.

FIG. 7C is an explanatory diagram relating to the application of stress in still another modification. As shown in Fig. 7C, heat is input from the upper side (sensor foil 4 side) for one strain transfer piece 3A, and heat input from the back side (thin film substrate 2 side) for the other strain transfer piece 3B. Even if it carries out, the recontact of the fracture | rupture ends after fracture | rupture of bridge | bridging part 4a, 4b can be prevented. However, in the case of Fig. 7C, the warping of the strain transmission piece 3A is not as significant as in Figs. 7A and 7B.

FIG. 8 is a perspective view for explaining an excessive strain detection mechanism of the strain detection device 1 shown in FIG. As shown in FIG. 8, the strain detection device 1 is in the same plane with the pair of strain transmission pieces 3A and 3B being coupled to the bridge portions 4a and 4b until the force is broken after being applied to the measurement object 10. The state of the bridge parts 4a and 4b can be reliably confirmed electrically by bringing the probe of the conduction tester T into contact with the electrode terminals 4e and 4f provided at the ends of the sensor foil 4. At the same time, it can be easily confirmed visually.

[0086] If excessive strain is generated in the object to be measured 10 during the milling period and the sensor foil 4 is broken at the positions of the bridge portions 4a and 4B, one strain transmitting piece 3A warps together with the sensor foil 4. It floats up and clearly shows the state of fracture. Therefore, the energization tester T in which the probe is connected to the electrode terminals 4e and 4f can easily detect the rupture state (non-conduction state) and can easily and accurately know the rupture state visually. In addition, solder wires to the electrode terminals 4e and 4f, and connect the electrode terminals 4e and 4f to the remote instruments via the wires, so that many strain detectors 1 are broken intensively in the remote areas. You may make it grasp.

[0087] Further, in the strain detection device 1 of the present embodiment, two bridge portions 4a and 4b are provided in the gap G. Since strain detector 1 has a structure that is vertically long in the direction of the detection axis, there is a risk that it may break during manufacturing or construction if there is only one bridge. Strength against bending by providing two bridges 4a and 4b Has improved and prevented accidents. [0088] In addition, since the bridge portions 4a and 4b are provided vigorously and the pair of electrode terminals 4e and 4f are provided on one end side of the strain detection device 1, the strain detection device T is used when inspecting with the energization tester T. If the probe is applied to one end of 1, the workability of the inspection can be improved. In addition, wiring is facilitated when an electric wire is connected to the electrode terminals 4e and 4f. In addition, since the bridge parts 4a and 4b are electrically connected in series, even if the breaking strength varies due to dimensional variations during manufacturing, the weaker one will surely break and become non-conductive. Therefore, reliability is improved.

[0089] In addition, the strain detection device 1 concentrates the amount of displacement generated in the detection region of a length L of several mm force and several hundred mm on the bridge portions 4a and 4b to break the sensor foil 4, and visually or energized tester. Since it is detected by a portable simple instrument such as T, the measurement object 10 can be diagnosed as a whole by setting a large number of measurement points. Furthermore, the strain detection device 1 can be formed in a small size with a length of 200 mm or less, and since there is no need for wiring to connect to the monitor by simply attaching it to the surface of the measurement object 10, the number of measurement points increases. However, the measurement cost does not increase.

The strain detection device 1 of the present invention can be used for long-term monitoring for monitoring the stress generated in the product structure throughout the service period. It is possible to detect excessive strain that occurs rarely during a long operation period. Long-term monitoring is possible because no measurement equipment is required. It can also be used for strain measurement in environments where measurement devices cannot be used, such as rotating objects, moving objects, and underwater objects. Furthermore, due to the simplicity and economy of the strain detection device, it is possible to extract the approximate distribution of generated strain and the location of the overstrain when applied to a wide measurement area or a large number of measurement points.

[0091] (Second Embodiment)

FIG. 9 is a perspective view of a strain detection apparatus 201 according to the second embodiment of the present invention. Note that portions common to the first embodiment are denoted by the same reference numerals, and the following description is omitted. As shown in FIG. 9, in the strain detection device 201 of the second embodiment, the thin film substrate 202 has a protrusion 202a that protrudes upward at a position corresponding to one strain transmission piece 3A. The protrusion 202a is formed between the bridge portions 4a and 4b and the spot welded portion Swl. It is formed by folding the plate 202 into a mountain shape, and extends in a direction perpendicular to the detection axis that coincides with the arrangement direction (tensile direction) of the strain transmitting pieces 3A and 3B. As a result, the strain transmitting piece 3A is applied with a force to warp upward, but the strain transmitting piece 3A is coupled to the other strain transmitting piece 3B by the sensor foil 4, so that deformation is prevented. Therefore, potential stress is inherent in the strain transmitting piece 3A.

FIG. 10 is a perspective view of the strain detection device 201 shown in FIG. 9 when the sensor foil 4 is broken. As shown in FIG. 10, when the bridge portions 4a and 4b are broken, the strain transmitting piece 3A is not restrained by the sensor foil 4, so the stress inherent in the strain transmitting piece 3A becomes obvious, and the strain transmitting piece 3A bridges. The end portions on the side of the parts 4a and 4b are deformed so as to be lifted from the thin film substrate 2. Therefore, the broken state of the sensor foil 4 can be detected easily and reliably.

[0093] (Third embodiment)

FIG. 11 is a perspective view of a strain detection device 301 according to the third embodiment of the present invention. Note that portions common to the first embodiment are denoted by the same reference numerals, and the following description is omitted. As shown in FIG. 11, in the strain sensing device 301 of the third embodiment, a spacer 310 such as a thin plate is sandwiched between one strain transmission piece 3A and the thin film substrate 2. Spacer 310 is disposed between bridge portions 4a and 4b and spot welded portion Swl, and extends in a direction perpendicular to the detection axis that coincides with the direction in which strain transmitting pieces 3A and 3B are arranged (tensile direction). And As a result, a force is applied to the strain transmission piece 3A to warp upward. The strain transmission piece 3A is coupled to the other strain transmission piece 3B by the sensor foil 4, and therefore, deformation is prevented. It is held in a flat state, and potential stress is inherent in the strain transmitting piece 3A.

FIG. 12 is a perspective view of the strain detector 301 shown in FIG. 11 when the sensor foil 4 is broken. As shown in FIG. 12, if the bridge portions 4a and 4b are broken, the strain transmitting piece 3A is not restrained by the sensor foil 4, so that the stress inherent in the strain transmitting piece 3A becomes obvious, and the bridge portion of the strain transmitting piece 3A It is deformed so that the ends on the 4a and 4b sides are lifted from the thin film substrate 2. Therefore, the broken state of the sensor foil 4 can be detected easily and reliably. Note that the protrusions 202a and the spacers 310 described above may be elastic bodies. If it is an elastic body, the broken state of the sensor foil 4 can be detected more reliably. [0095] (Fourth Embodiment)

FIG. 13 is a perspective view of the strain detection apparatus 1 according to the fourth embodiment of the present invention. Note that portions common to the first embodiment are denoted by the same reference numerals, and the following description is omitted. As shown in FIG. 13, the strain detection device 1 of the fourth embodiment is the same as that of the first embodiment, but the installation mode on the measurement object is different. Specifically, the strain detection device 1 is affixed to the curved surface portion of the measurement object, and at least a part 2a of the thin film substrate 2 on the strain transmission piece 3A side is convex toward the upper side (strain transmission piece 3A side). It is used in a curved state. As a result, the strain transmitting piece 3A is applied with a force to warp upward, but the strain transmitting piece 3A is coupled to the other strain transmitting piece 3B by the sensor foil 4, thereby preventing deformation. Thus, the curved shape along the thin film substrate 2 is held, and potential stress is inherent in the strain transmitting piece 3A.

FIG. 14 is a perspective view of the strain sensing device 1 shown in FIG. 13 when the sensor foil 4 is broken.

As shown in FIG. 14, when the bridge portions 4a and 4b are broken, the strain transmitting piece 3A is not restrained by the sensor foil 4, so that the stress inherent in the strain transmitting piece 3A becomes obvious, and the strain transmitting piece 3A The ends of the bridge portions 4a and 4b are deformed so as to be lifted from the thin film substrate 2. Therefore, the broken state of the sensor foil 4 can be detected easily and reliably.

[0097] (Fifth embodiment)

FIG. 15 is a plan view of a strain detection apparatus according to the fifth embodiment of the present invention. As shown in FIG. 15, in this embodiment, strain detection is formed by arranging three sets of strain detection sensors 6 having the same configuration as that used in the first embodiment on one thin film substrate 2. It is device 11. Since the detection characteristics of the strain detector 11 are based on the fracture characteristics of the material, there are variations in detection accuracy due to material variations and manufacturing variations. The variation in detection accuracy is the square root of the root mean square of the accuracy variation of each sensor when multiple sensors are used, so the detection accuracy can be improved by providing multiple strain detection sensors 6. .

The strain transmission pieces 3A and 3B are fixed to the thin film substrate 2 at predetermined positions Swl and Sw2 by spot welding, respectively. In addition, one strain transmission piece 3B receives heat at an intermediate position Sh between the bridge portion and the fixed position Sw2 to such an extent that it is not welded by a spot welder. Yes. As a result, when the bridge portion breaks, a stress is applied to the strain transmitting piece 3B such that it breaks in the vicinity of the intermediate position Sh and the broken end tends to jump upward.

[0099] The strain detector 11 is adhered to the surface of the object to be measured, and the fracture state is observed after an appropriate time has elapsed. As a result of observation, when all of the sensor foils 4 of the plurality of strain detection sensors 6 are broken, it can be determined that the object to be measured has generated a stress larger than the detection stress σ of the sensor. If the sensor 6 is not broken, it can be determined that no stress greater than the detected stress σ of the sensor has occurred. In addition, when several sensor foils 4 of the plurality of strain detection sensors 6 are ruptured and the rest are not ruptured, the variation of the detected stress σ is positively used, and the hysteresis stress of the measurement object is detected by the sensor. Within the variation range of the detected stress σ, that is, between the upper limit value σ and the lower limit value σ

-Can be estimated to be between +.

[0100] Furthermore, the three-thread and strain-detecting sensor 6 is formed in the same shape and arranged in parallel with each other. However, the strain transmitting piece 3 片 on the left side in the figure is fixed to the thin film substrate 2 with a spot welder. The Swl may be configured to be different for each of the three sets of strain detection sensors 6. Then, each strain detection sensor has a different detection stress, and can be configured to have, for example, detection stresses σ ΐ, σ 2, σ 3 that are different in the order of upward force in the figure.

[0101] In this way, a strain detection device formed so that the detection stress σ is different for each of the plurality of strain detection sensors is attached to the surface of the object to be measured, and observed after an appropriate time has elapsed. At this time, the approximate value of the hysteresis stress of the measurement object can be estimated by specifying the strain detection sensor that has broken. For example, when all of the strain detection sensors are not broken, it can be seen that the measurement object has received a hysteresis stress smaller than the smallest detection stress σ 1. In addition, when the upper strain detection sensor in the figure breaks, it is assumed that the measurement object has received a hysteresis stress that is larger than the detection stress σ 1 of the upper strain detection sensor and smaller than the detection stress σ 2 of the central strain detection sensor. Can think. Furthermore, it can be seen that when all strain detection sensors were damaged, a hysteresis stress greater than the detection stress σ 3 of the lower sensor was received. Although not shown in FIG. 15, even in a strain detection device in which a plurality of strain detection sensors having the combined force of the sensor foil 4 and a pair of strain transmission pieces 3 mm and 3 mm are formed, a reinforcing frame connected to the strain transmission pieces is provided. By providing, to the measurement object Needless to say, it is easy to handle before sticking! /.

[0102] (Sixth embodiment)

FIG. 16 is a plan view of a strain detection apparatus according to the sixth embodiment of the present invention. As shown in FIG. 16, the strain detection device 21 of the present embodiment is formed by arranging two sets of strain detection sensors 6 side by side on one thin film substrate 2.

[0103] The strain transmitting pieces 3A and 3B are welded and fixed to the thin film substrate 2 by a spot welder at one force point Swl and Sw2, respectively. The distance between the fixed positions of the pair of strain transmission pieces 3A and 3B may be different between the two sets of strain detection sensors 6. When the distance between the fixed positions is different, the detected stress σ differs for each strain detection sensor. In addition, one strain transmitting piece 3 入 receives heat at an intermediate position Sh between the bridge portion and the fixed position Swl to such an extent that it is not welded by a spot welder. Stress is applied to warp upward.

[0104] The strain detection device 21 is adhered to the surface of the object to be measured, and the fracture state is observed by an operator after an appropriate time has elapsed. The observation may be performed by detecting electrical resistance via the electrode terminals, and the warping state of the strain transmitting piece 3A may be confirmed visually. As a result of observation, if both of the two strain detection sensors 6 break, the two objects are detected by the two strain detection sensors. If neither breaks, the stress of the two strain detection sensors is less than the detected stress σ1, σ2, or when one strain detection sensor breaks and the other pair breaks Therefore, it is possible to estimate that the stress between the detected stresses σ 1 and σ 2 of the two sets of strain sensors was recorded.

FIG. 17 is an explanatory diagram of a method for specifying a detected stress range using the strain detection apparatus shown in FIG. As shown in Fig. 17, the measurement range of the first strain detection sensor S1 is between the lower limit σ and the upper limit σ across the detected stress design value σ.

1 1- 1 +

The range is the lower limit with a design value σ of detected stress larger than that of the first strain sensor.

2

From σ to the upper limit σ, from the upper limit σ of the detected stress of the first strain detection sensor SI

2- 2+ 1+ Detected stress lower limit σ of second strain detection sensor S2 is small.

2-

[0106] Then, if both strain detection sensors SI and S2 of 2ffi ^ are conducting, the first Upper limit value of strain detection sensor σ

It can be judged that a stress greater than 1+ was not applied. Also, when the first strain detection sensor S1 is disconnected and the second strain detection sensor S2 is conductive, the lower limit value σ of the first strain detection sensor and the upper limit value σ of the second strain detection sensor It is judged that the stress in between may have acted. In addition, two strain detection sensors

2 +

If both SI and S2 are disconnected, it can be judged that at least a stress greater than the lower limit σ of the second strain detection sensor is applied.

2-

[0107] The second strain detection from the upper limit σ of the detected stress of the first strain detection sensor S1

1+

Lower limit of detection stress of sensor S2 σ force, in this case, the first strain detection sensor S1

2- There may be a case where the second strain detection sensor S2 is disconnected, and in this case, between the upper limit value σ of the first strain detection sensor and the lower limit value σ of the second strain detection sensor.

1+ 2- Judge that the stress was applied. In the second and sixth embodiments, a force in which two or three strain detection sensors are provided on one thin film substrate 2 may be provided, and a number of strain detection sensors may be provided.

[Seventh Embodiment]

FIG. 18 is an explanatory diagram of a strain detection apparatus according to the seventh embodiment of the present invention. As shown in FIG. 18, the strain detection device 1 attached to the measurement object of this embodiment is covered with a protective cover 30. The protective cover 30 is made of a resin material, a polished steel plate, a coated steel plate, or the like, and is formed in a lid shape that can cover the strain detector 1. The protective cover 30 protects the strain detection device 1 by hermetically sealing the interior of the object to be measured to the surface of the object to be measured by using grease or the like. Note that the electric wire 34 connected to the electrode terminal in order to electrically detect the breakage of the sensor foil 4 is led out from the protective cover 30 in an airtight manner.

[Eighth Embodiment]

FIG. 19 is an explanatory view of a strain detection apparatus according to the eighth embodiment of the present invention. As shown in FIG. 19, the strain detection device 1 of the present embodiment is coated with a force-resin coating 32 to block outside air, and can be used for a long time. In addition, it is preferable to provide a sufficient cavity that is coated with an upper-strength resin having a cover of an appropriate size and allows the strain transmitting piece to warp. In order to detect the breakage of the sensor foil 4 electrically, The electric wire 34 connected to the child is led out from the resin coating 32 in an airtight manner.

[0110] (Ninth Embodiment)

FIG. 20 is a plan view of a strain detection apparatus according to the ninth embodiment of the present invention. As shown in Fig. 20, there are multiple measurement systems for cases where the structure of the object to be measured is complex and the direction of stress cannot be determined in advance, or for earthquakes in which the maximum strain direction cannot be predicted. It is convenient to use the multi-axis strain detection device 41 in which the strain detection sensors 6 are radially arranged with the detection axis directions slightly shifted from each other, since the unknown maximum strain direction is not overlooked.

[0111] (Tenth embodiment)

FIG. 21 is a block diagram of a strain detection system 50 according to the tenth embodiment of the present invention. As shown in FIG. 21, the strain detection system 50 according to the present embodiment includes a strain detection device 1, a data detection transmission device 51, an independent power source 52, and a reception device 53. Note that the strain detection device 1 described in the first embodiment is used.

[0112] The data detection transmission device 51 is connected to the electrode terminals 4e and 4f of the strain detection device 1 via the electric wire 34. The data detection transmission device 51 is connected to the electrode terminals 4e and 4f to detect a breakage (non-conduction) of the bridge portions 4a and 4b, and receives a detection signal when the breakage is detected by the detection circuit. 53 has a transmission circuit for wireless transmission. The data detection transmission device 51 is installed close to the strain detection device 1, and the detection circuit detects the presence or absence of breakage of the sensor foil 4 by inspecting the current or resistance between the electrode terminals 4e and 4f, and the transmission circuit. Transmits the detection result wirelessly to the receiving device 53 in a non-contact manner.

The independent power supply 52 is disposed in the vicinity of the data detection transmission device 51 or installed in a form incorporated in the data detection transmission device 51, and supplies power to the data detection transmission device 51. The independent power source 52 is an independent device that uses dry cells, solar cells, etc. to eliminate the need for troublesome wiring for the strain detection device 1 and to eliminate on-site wiring work by an electrician.

[0114] In the present embodiment, the data detection transmission device 51 electrically detects and detects that the electrode terminals 4e and 4f become non-conductive when the load acting on the measurement object exceeds a predetermined value. A signal is transmitted, and the receiving device 53 receives the detection signal wirelessly and detects an abnormality. Receiver At 53, when an abnormality occurs, an alarm is given to the worker, the abnormal part is displayed and notified, and measures are taken to avoid danger such as issuing an emergency evacuation order or emergency stop of equipment. be able to. In this embodiment, the strain detection device 1 and the reception device 53 may be separated from each other. Therefore, it is not necessary for an operator to directly access the strain detection device 1, and a large number of detection results are collected and measured. It can also be used to diagnose the entire object.

[0115] (Eleventh embodiment)

FIG. 22 is a block diagram of a strain detection system according to the eleventh embodiment of the present invention. As shown in FIG. 22, the strain detection system 60 of the present embodiment uses a personal computer 61 with a modem 62 having a signal input device PIO as corresponding to the data detection transmission device 51 in the aspect of FIG. Therefore, the detection signal received by the receiving device is transmitted to the central monitoring room 63 (not shown). The detection signal received in the central monitoring room 63 is signal-processed, and when it is determined to be abnormal, an alarm or emergency stop measures can be taken.

[0116] It is used when monitoring a remote measurement object closely, or when monitoring a very large number of strain detection devices. In this embodiment, since a commercially available personal computer having a high function and a low price can be used, a high-function and low-cost system can be easily constructed. By using such a monitoring system, a large amount of information about the presence or absence of excessive strain on the measurement object is automatically collected in the central monitoring room 63, so that the overall situation can be reduced by a small number of workers in the central monitoring room 63. Can be grasped.

[0117] (Twelfth embodiment)

FIG. 23 is a block diagram of a strain detection system 70 according to the twelfth embodiment of the present invention. As shown in FIG. 23, the strain detection system 70 of the present embodiment is one in which an IC tag 71 is connected to the strain detection device 1. The IC tag 71 is provided with a detection circuit and a transmission circuit. The IC tag 71 is attached to the object to be measured with its terminals connected to the electrode terminals 4e and 4f of the strain detection device 1. Then, if necessary, the IC tag reading device 72 is held over the IC tag 71, so that the IC tag reading device 72 reads out the presence / absence information of excessive strain from the IC tag 71. Alternatively, IC tag reader 7 for each of multiple strain detectors 1 2 is provided, and the detection results are always transmitted from the IC tag reader 72 to a predetermined management location for centralized management.

[0118] The IC tag 71 operates in a non-contact manner by receiving energy supply from the IC tag reader 72 when the IC tag reader 72 is approached, detects the breakage state of the sensor foil, and detects the detected information as IC Since it is wirelessly transmitted to the tag reader 72, a power supply device is not required inside. Since the IC tag 71 is sufficiently small and light, it can be attached to a rotating member of a rotating machine integrally with the strain detection device 1 to detect a load state during operation.

[0119] It should be noted that the operator moves the IC tag reading device 72 held around the place where the strain detection device 1 and the IC tag 71 are installed over the IC tag 71, so that the IC tag reading device 72 becomes the IC tag 71. Since the information related to the presence or absence of sensor foil breakage is read and displayed in a non-contact manner or the information is stored in the IC tag reader 72, it is extremely labor-saving even when a lot of places scattered over a wide area are inspected. Data can be collected.

[0120] (Thirteenth embodiment)

FIG. 24 is a block diagram of a strain detection system according to the thirteenth embodiment of the present invention. As shown in FIG. 24, the data detection transmission device 51 connected to the strain detection device 1 transmits the detection result to the determination device 81. The determination device 81 determines the detection result based on a predetermined determination criterion, and drives the display device 82 based on the determination result. The display device 82 is equipped with devices that appeal to the sense of sight and hearing, such as indicator lights, liquid crystal display devices, and speakers. Notify the worker by generating an audible voice.

[0121] The determination device 81 and the display device 82 may be placed at a position away from the measurement object, and the detection result may be transmitted wirelessly from the data detection transmission device 51, or the data detection may be performed. It may be attached to the measurement object together with the transmission device 51 to display an alarm signal or the like at the location of the measurement object. The data detection transmission device 51 and the like are driven by an independent power source 52 installed in the field.

[0122] (14th embodiment)

FIG. 25 is a block diagram of a strain detection system 90 according to the fourteenth embodiment of the present invention. As shown in FIG. 25, the strain detection system 90 of the present embodiment is a temperature sensor or the like. By using the state sensor 91, an appropriate strain detection sensor SI, S2 is selected and the state is judged. In FIG. 25, two or more forces in which two strain detection sensors are arranged may be used. The strain detection device 21 includes strain detection sensors SI and S2 having different detection levels as in the sixth embodiment. The data detection transmission device 51 is connected to these strain detection sensors SI and S2. Further, the data detection transmission device 51 is connected to the state sensor 91, and the measured value of the state variable that affects the measurement object is input from the state sensor 91 and transmitted to the determination device 92. The determination device 92 selects an appropriate strain detection sensor based on the measurement value of the state sensor 91, determines whether or not an excessive strain state has occurred in the measurement object, and drives the display device 82.

[0123] As the state sensor 91, a sensor that measures a state variable that affects the stress state, such as a temperature sensor, an acceleration sensor, an angular velocity sensor, a vibration sensor, or a displacement sensor, is selected. For example, when the temperature changes, the stiffness of the measurement object changes, the stress strain coefficient changes, and the fracture load value may also change. Therefore, a plurality of strain detection sensors SI and S2 with different breaking strains of the sensor foil are arranged, and an appropriate strain detection sensor is selected based on information from the state sensor 91.

FIG. 26 is an explanatory diagram for explaining the function of the strain detection system 90 shown in FIG. As shown in FIG. 26, the first strain detection sensor S1 is adjusted so that the sensor foil breaks when a predetermined load W1 is applied to the measurement object. The second strain detection sensor S2 is adjusted so as to be broken when a load W2 larger than W1 is applied. In the same manner, strain detection sensors S3, S4, S5, and S6 are arranged so as to detect appropriate loads W3, W4, W5, and W6 in sequence.

[0125] In the high temperature range T5 to T6, there is a danger that the structure will be abnormal even with a small load. Therefore, the fracture state of the strain detection sensor S1 that breaks with a small load W1 is monitored. On the other hand, in the low temperature range Τ1 to うる 2, it can withstand a large load, so a large load W5 is not applied! / And the soundness of the structure is judged by the rupture state of the strain detection sensor S5 To do.

[0126] For example, when the measured value Tm of the temperature sensor is within the temperature range Τ3 to Τ4, the judgment device 92 selects the strain detection sensor S3, and whether the sensor foil breaks or not is also necessary to alarm. Determine. In this case, even if the low-temperature strain detection sensors S1 and S2 prepared for the higher temperature region are broken, they are ignored.

[0127] When a vibration sensor is used as the state sensor 91, when the vibration is large, a highly sensitive strain detection sensor is selected and the presence or absence of the sensor foil is checked. When the vibration is small, the sensitivity is low and the strain is low. When the detection sensor is selected and the presence or absence of sensor foil breakage is observed, it is possible to change the detection level for sudden overload by judging the operating status of the equipment. Further, when an acceleration sensor, an angular velocity sensor, a displacement sensor, or the like is used as the state sensor 91, it can be used to select a strain detection sensor corresponding to the measured value by the determination device as described above.

[0128] Next, Figs. 27 to 37 are diagrams for explaining examples of use of the strain detection device of the present invention. By devising the position and method of applying the strain detection device for various measurement objects, The advantages of the present invention can be fully exhibited.

[0129] (First usage example)

FIG. 27 is a schematic diagram showing a first usage example of the strain detection device of the present invention. As shown in Fig. 27, in this use case, a strain detector is used for the falling bridge warning in the bridge 100. Alarms can be issued by detecting abnormal loads and abnormal displacements of expansion and contraction devices and falling bridge prevention devices that occur during an earthquake. A long bridge 100 having a plurality of bridge girders 101 is provided with bridge piers 103 at appropriate intervals between the abutments 102 built at both ends of the bridge, and the bridge girders 101 are hung between the abutment 102 and the pier 103 or between the piers 103. It is formed by connecting.

[0130] Since the bridge girder 101 expands and contracts mainly due to temperature, it cannot be completely fixed to the abutment 102 or the pier 103. Further, at both ends of the bridge girder 101, an expansion / contraction device 104 is interposed in order to prevent the bridge girder 101 from expanding and contracting due to a temperature change and generating a gap between the bridge beams 101. The telescopic device 104 can be configured, for example, by forming comb-shaped protrusions at the end of the bridge beam 101 and arranging the teeth of the combs on both sides to face each other. Furthermore, in order to prevent the bridge girder 101 from falling even if there is an earthquake, the bridge girder 101 at both ends is equipped with the abutment 102, and the bridge girder 101 is also connected with a falling bridge prevention device 105, 106 that couples the beam girder 101 with beams or cables.

[0131] It is preferable to block traffic in advance when danger is expected due to abnormal force. That's right. Therefore, the strain detection device 1 adjusted so that the sensor foil breaks in the vicinity of the strain corresponding to the limit state where the bridge can be safely bridged is attached to the beam of the fall prevention device 105, 106, the support of the cable, etc. If a warning is issued when a strong force is received, appropriate measures can be taken to ensure safety before a serious accident occurs. Alarms can be displayed at the location of the bridge 100, or the management office can be notified to take appropriate measures.

[0132] (Second usage example)

FIG. 28 is a schematic view showing a second usage example of the strain detection apparatus of the present invention. As shown in FIG. 28, the pier 112 on which the bridge 111 is placed is made of reinforced concrete, and the foundation pile 114 is driven and fixed to a sufficient depth underground. However, the sturdy pier 112 will also be damaged in the event of a major earthquake. For this reason, it is required to design and construct exactly knowing what kind of structure and how much earthquake it can withstand. It is economically difficult to constantly monitor the stresses generated using expensive measuring instruments, and it is difficult to systematically collect actual data for rare earthquakes. Therefore, it is reasonable to collect data after an earthquake has occurred by attaching an inexpensive strain detector 1 to the part to be measured.

[0133] In this use example, an appropriate number of strain detection devices 1 with different break strain settings are installed in advance, and the strain detection device 1 that breaks after an earthquake occurs and the strain detection device 1 that does not break. By dividing, the actually generated stress can be estimated. In addition, when using the strain detection system 70 having the IC tag 71 as in the twelfth embodiment, the surface force of the strain detection device 1 and the IC tag 71 sensor embedded inside can be searched to know the detection result. it can.

[0134] Damaged columns and reinforcing bars may not be observed from the outside. For example, a large number of strain detectors 1 with different set breaking strains are attached to the reinforcing bars 113 inside the concrete. The pier 112 may be formed by covering with concrete. After the earthquake occurs, the strain detecting device 1 that has broken and the strain detecting device 1 that has not broken can be examined to accurately estimate the maximum stress applied to the reinforcing bar 113. Based on this result, it is possible to judge the availability of service after the earthquake and the necessity for repair. Also, damaged part and sound By analyzing the maximum stress in the part, valuable design data can be obtained.

[0135] Since the foundation piles 114 are buried underground, the stress received by each foundation pile 114 cannot be easily known. However, according to this use example, it is also detected from the buried strain detection device. Since the data can be acquired, the stress received by the foundation pile 114 can be estimated, which is extremely effective for earthquake analysis.

[0136] (Third use example)

FIG. 29 is a schematic view showing a third usage example of the strain detection apparatus of the present invention. As shown in FIG. 29, in this use example, a strain detector is used to estimate the stress application state in the expansion joint arranged in the pipe. The expansion joint 120 having a bellows pipe is provided in the middle of the pipe, and absorbs the expansion / contraction allowance of the pipe based on changes in temperature and fluid pressure. As a method for detecting an abnormality in the expansion joint 120, the strain detection device of the present invention can be used.

[0137] If the strain detector 1 is attached to the surface of the bent portion 121 of the bellows tube, or the strain detector 1 is attached to the bolt 122 with the bellows portion sandwiched between flanges and tightened between the flanges, An abnormality can be easily detected and an alarm can be issued.

[0138] (Fourth use example)

FIG. 30 is a schematic view showing a fourth example of use of the strain sensing device of the present invention. As shown in Fig. 30, in this use example, the torsional load on the rotating shaft in the rotating equipment is monitored by a strain detector. The rotating shaft 130 connecting the drive unit and the load unit generates a shearing force due to a torsional load, and the maximum strain direction generated on the surface of the rotating shaft 130 is inclined by approximately 45 ° to the shaft. . Therefore, the strain detector 1 must be attached with the detection axis inclined at 45 ° to the direction of the rotation axis, and the maximum strain must be accurately detected.

FIG. 31 is a plan view of a strain detector 140 of a modified example in which shear stress is detected for application to the rotating shaft 130 and the like shown in FIG. When a shear force acts on the measurement object, the direction of the maximum strain on the surface of the measurement object has a predetermined inclination with respect to the direction of the force. Therefore, if the detection axis direction of the strain detection sensor 6 of the strain detection device 140 is adjusted to the maximum strain direction from the beginning, there is no need to adjust the angle when the strain detection device 140 is attached to the measurement object. Convenient. FIG. 31 shows a strain detection device 140 formed on the premise that it is applied to a rotating shaft or the like, and the strain detecting sensor 6 is formed with an inclination of 45 ° with respect to the axial direction of the rotating shaft. That is, the strain transmitting pieces 3A and 3B (see FIG. 1) are arranged at the center position of the rectangular thin film substrate 2 so as to have a detection axis in a direction inclined by 45 ° with respect to the side. When the strain detection device 140 formed in this way is attached so that the side of the thin film substrate 2 is aligned with the axial direction of the rotation axis, the detection axis direction of the strain detection sensor 6 is the maximum strain on the surface of the rotation axis. This is convenient because the maximum stress is detected in accordance with the direction of the peak.

[0141] (Fifth use case)

FIG. 32 is a schematic view showing a fifth usage example of the strain detection apparatus of the present invention. As shown in FIG. 32, in this use example, the strain detection device 21 is applied to a crane. A strain detection unit 155 with a strain detection device 1 for detecting an abnormal load is interposed in a portion where the wire 152 for hanging the pulley 151 of the crane 1 50 is fixed to the crane body.

[0142] When the load suspended by the crane 150 approaches the maximum load that can be hung, the sensor foil of the strain detector 1 breaks and generates a danger signal. The receiving device that receives the danger signal gives a warning to the operator and stops the operation. If the load is close to the dangerous load and the danger is imminent, an emergency stop may be automatically performed. Since the dangerous load that causes the crane 150 to fall or break varies depending on the crane angle, several strain detectors 1 and angle sensors are used in combination to switch off the strain detector 1 to be used for each measured angle range. It may be possible to make an accurate judgment of the risk level.

FIG. 33 is a plan view of the strain detection unit 155 used in FIG. As shown in FIG. 33, the strain detection unit 155 is formed by attaching the strain detection device 1 to a central flat portion 157 of a bar piece 158 having suspension holes 156 at both ends. The material and shape of the bar piece 158 can be arbitrarily selected to suit the load detection. Further, since the strain detection unit 155 has reproducibility, the detection load can be determined experimentally and is highly reliable. Such a general-purpose strain detection unit 155 can be applied to various objects such as crane abnormal load detection.

[0144] (Sixth use example)

FIG. 34 is a schematic view showing a sixth example of use of the strain sensing device of the present invention. Shown in Figure 34 As described above, this use example uses a strain detection device as an overload warning device for a hanging wire. The suspension wire 161 breaks and drops a cargo when a cargo exceeding a predetermined load is suspended. Therefore, it is preferable to confirm that an excessive load is not suspended and to alert the driver or stop the operation when an excessive load is accidentally applied.

[0145] Therefore, a pair of guide rollers 162 is provided on the path of the suspension wire 161, and the detection roller 164 is disposed between the guide rollers 162, and the detection roller 164 is pressed by the tension of the suspension wire 161 generated by the load. The sensor plate 165 is displaced, and a detection signal is generated when the displacement exceeds a predetermined value.

FIG. 35A is a side view of sensor plate 165 shown in FIG. FIG. 35B is a plan view of the sensor plate 165 shown in FIG. As shown in FIG. 35A and FIG. 35B, the sensor plate 165 is obtained by attaching the strain detection device 1 of the present invention to the back side of a strip-shaped substrate 166 provided with a stop hole 166a at both ends, and installed at an appropriate interval. The fixed object 168 is fixed to the lower surface of the fixed object 168 with a stopper 167 through a stop hole 166a, and is arranged so that the detection roller 164 contacts the lower surface of the intermediate part.

[0147] When the axial position of the detection roller 164 is displaced due to the tension of the hanging wire 161, the sensor plate 165 is squeezed and the thin film substrate 2 (see Fig. 1) of the strain detection device 1 is stretched to reach a preset strain. The sensor foil 4 (see Fig. 1) breaks and an abnormality can be detected. The detection signal is transmitted to a receiving device as shown in FIGS. 21 to 23, and is transmitted to the driver as an alarm signal, or the driving of the hanging wire 161 is controlled to stop.

[0148] (Seventh use example)

FIG. 36 is a schematic view showing a seventh example of use of the strain sensing device of the present invention. FIG. 37 is an enlarged view of the main part of FIG. As shown in Fig. 36 and Fig. 37, at the part where the bridge girder 170 engages with the abutment 171, the horizontal distance between the bridge girder 170 and the abutment 171 is monitored to detect anomalies that are larger than the predetermined distance. A detection unit 155 and a sensor plate 165 that is installed in a portion where the end of the bridge girder 170 is placed and detects an abnormal load are provided.

[0149] The strain detection unit 155 is the same as that described in Fig. 33, and is adjusted so that the sensor foil breaks when the distance between the bridge girder 170 and the abutment 17 1 reaches a predetermined dangerous displacement amount. Yes. The sensor plate 165 provided under the bridge girder 171 is the same as that described in FIGS. 35A and 35B.

[0150] On the lower surface of the bridge girder 170, a pressing pin 172 that pushes down the sensor plate 165 protrudes downward. That is, the pressing pin 172 moves up and down as the bridge girder 170 is displaced in the vertical direction. Since the bridge girder 170 has a fulcrum 175 on the upper surface of the abutment 173, it sinks around the fulcrum 175 when a load is applied. The pressing pin 172 is formed so that its tip protrudes in a circular arc shape. When the upper surface of the sensor plate 165 is pressed as the bridge girder 170 sinks, the thin film of the strain detection device 1 attached to the lower surface of the sensor plate 165 When the substrate 2 (see Fig. 1) stretches and reaches a preset strain, the sensor foil 4 (see Fig. 1) breaks and an abnormality can be detected. Therefore, the sensor plate 165 of this use example detects an abnormality when an excessive load is loaded on the bridge girder 170 and issues an alarm or automatically displays a prohibition of entry. be able to.

[0151] The strain detection device of the present invention described above does not require an advanced instrument for measurement, and can be used for long-term monitoring to monitor strain generated in the structure of the product throughout the service period. It is possible to detect excessive strain that occurs rarely during the operation period. It can also be used for strain abnormality alarms in environments where measuring devices cannot be used, such as rotating objects, moving objects, and underwater objects. Furthermore, due to the simplicity and economy of this strain detection device, it can be applied to a wide range of measurement or a large number of measurement points to identify the approximate distribution of generated stress and the location where the overstress occurs. In addition, any load value can be measured by measuring the stress generation part of steel materials in various structures, transportation equipment, buildings, machines, etc. such as cranes, bridges, railway vehicles, aircraft, automobiles, building steel frames, reinforcing bars, rotating machines, etc. It can be set to be sensitive to the displacement value, and when it exceeds this value, an alarm can be issued or an emergency measure can be taken directly. When applying the strain detection device of the present invention to these steel materials, an organic adhesive can be used, or welding can be used. Furthermore, the strain detection device of the present invention can be applied to any material as long as the sensor can be adhered to the stress generating part, such as non-ferrous materials, polymer materials, composite materials, concrete, asphalt, and wood, in addition to steel materials. Is possible.

Claims

The scope of the claims

[1] a thin film substrate that is attached to the measurement object and distorted together with the measurement object;

A pair of strain transmitting pieces, which are opposed to each other with a small gap on the thin film substrate, each fixed to the thin film substrate at at least one force point;

A sensor foil having a bridge portion that is affixed across the pair of strain transmission pieces and has a bridge portion having a smaller cross-sectional area than the position affixed to the strain transmission piece at a position corresponding to the gap;

One of the pair of strain transmitting pieces has a stress that tends to warp in a direction away from the thin film substrate.

[2] The strain detection device according to claim 1, wherein the sensor foil includes a plurality of the bridge portions in a portion crossing the gap.

[3] The strain transmitting piece is applied with the stress by applying heat to a portion between the gap position and a position fixed to the thin film substrate so as not to join the thin film substrate. The strain detection device according to claim 1.

[4] The strain transmitting piece is melt-bonded at a portion where the strain transmitting piece is fixed to the thin film substrate by heat input from the thin film substrate side with a local heating device, while the position of the gap and the 4. The stress is applied to the position between the position fixed to the thin film substrate from the strain transmission piece side by applying heat to such an extent that it is not joined to the thin film substrate by a local heating device. Strain detector.

[5] The strain transmitting piece and the sensor foil are made of metal,

The strain detection device according to claim 1, wherein an insulating adhesive layer is interposed between the strain transmission piece and the sensor foil.

[6] The strain transmitting piece is integrally connected to a part of the strain transmitting piece, surrounds the strain transmitting piece, and the reinforcing frame having the same material force as the strain transmitting piece is removed. The strain detection device according to claim 1, wherein the strain detection device is formed by:

[7] Between the strain transmitting piece and the reinforcing frame, a folding line is provided in which elongated holes separated by a thin connecting portion are arranged, and the reinforcing frame is removed by breaking the connecting portion. The strain detection device according to claim 6, wherein

[8] A plurality of strain detection sensors, which are a combination of the pair of strain transmitting pieces and the sensor foil, are arranged on the thin film substrate,

The distance between the fixed position of one of the pair of strain transmitting pieces to the thin film substrate and the fixed position of the pair of strain transmitting pieces to the other thin film substrate is the plurality of strain detecting sensors. The strain detection apparatus according to claim 1, which is different for each.

[9] A plurality of strain detection sensors, which are a combination of the pair of strain transmission pieces and the sensor foil, are arranged on the thin film substrate,

The distance between the fixed position of one of the pair of strain transmitting pieces to the thin film substrate and the fixed position of the pair of strain transmitting pieces to the other thin film substrate is the plurality of strain detecting sensors. The strain detection device according to claim 1, which is mutually the same.

10. The strain detection device according to claim 1, wherein a strain detection sensor that is a combination of the pair of strain transmission pieces and the sensor foil is surrounded by a protective cover.

[11] The strain detection device according to claim 1, wherein a resin coating is applied to a strain detection sensor which is a combination of the pair of strain transmission pieces and the sensor foil.

12. The strain detection device according to claim 1, wherein the sensor foil has a pair of electrode terminals that have a conductive force and are conducted through the bridge portion.

[13] The sensor foil according to claim 12, wherein the sensor foil includes a plurality of the bridge portions at a portion crossing the gap, and the electrode terminals are gathered on one side of the pair of strain transmission pieces. The strain detector described.

[14] The sensor foil has a plurality of the bridge portions in a portion crossing the gap, and the electrode terminal is formed at an end portion of the sensor foils connected in series. The strain detection apparatus according to claim 12.

[15] The strain detection device according to claim 12,

A detection circuit connected to the electrode terminal of the strain detection device and detecting breakage of the bridge portion;

A transmission circuit that transmits a detection signal when a break is detected by the detection circuit, and a reception device that receives the detection signal of the transmission circuit force. Strain detection system.

16. The strain detection system according to claim 15, further comprising an independent power source that supplies power to the detection circuit and the transmission circuit.

[17] The detection circuit and the transmission circuit are part of an IC tag, and the IC tag includes a storage unit that stores information on whether or not a break is detected by the detection circuit,

16. The strain detection system according to claim 15, wherein the receiving device is an IC tag reading device capable of reading information from the storage unit of the IC tag.

[18] The strain detection device includes a plurality of strain detection sensors on the thin film substrate, and a fixed position of one of the pair of strain transmission pieces on the thin film substrate. And the distance between the fixed position to the other thin film substrate of the pair of strain transmission pieces is different for each of the plurality of strain detection sensors,

A state sensor for detecting a state other than the strain of the measurement object; and a determination circuit for selecting one of the plurality of strain detection sensors to be used for strain detection based on the output of the state sensor. The strain detection system according to claim 15.

19. The strain detection system according to claim 15, further comprising an alarm device that generates an alarm when the breakage of the bridge portion is detected by the detection circuit.