WO2022113235A1 - Looseness detection sensor and loose bolt identification method - Google Patents

Looseness detection sensor and loose bolt identification method Download PDF

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Publication number
WO2022113235A1
WO2022113235A1 PCT/JP2020/044010 JP2020044010W WO2022113235A1 WO 2022113235 A1 WO2022113235 A1 WO 2022113235A1 JP 2020044010 W JP2020044010 W JP 2020044010W WO 2022113235 A1 WO2022113235 A1 WO 2022113235A1
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Prior art keywords
conductive layer
resonance frequency
bolt
looseness
detection sensor
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PCT/JP2020/044010
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French (fr)
Japanese (ja)
Inventor
恵里 松永
正成 庄司
昌幸 津田
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日本電信電話株式会社
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Application filed by 日本電信電話株式会社 filed Critical 日本電信電話株式会社
Priority to JP2022564908A priority Critical patent/JP7502683B2/en
Priority to PCT/JP2020/044010 priority patent/WO2022113235A1/en
Publication of WO2022113235A1 publication Critical patent/WO2022113235A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means

Definitions

  • the present invention relates to a looseness detection sensor that detects looseness of bolts that fix two or more parts, and a method of identifying loose bolts.
  • Bolts are used to tighten and fix parts to parts, and are used for various purposes from large equipment such as infrastructure structures and plant equipment to familiar products such as vehicles, playsets, and furniture. At the bolt joint, loosening or falling off may occur due to deterioration such as composition deformation and fatigue due to vibration or excessive force.
  • Non-Patent Document 1 Non-Patent Document 1
  • the method of monitoring the deviation of the matching mark and the tapping sound inspection are not suitable for the inspection of the part where the inspection target is difficult to see or the inspection target is far away and it is difficult to visually inspect.
  • the inspection method using ultrasonic waves is costly because the measuring instrument is carried to a place with poor workability such as a high place for inspection. There is also the problem of being dangerous. As described above, there is a problem that there is no suitable method and method for inspecting looseness of the tightened portion of the two parts by the bolt.
  • the present invention has been made in view of this subject, and provides a looseness detection sensor suitable for inspecting looseness of a tightened portion of two or more parts by a plurality of bolts, and a method for identifying loosened bolts. With the goal.
  • the looseness detection sensor is a ring-shaped sensor that detects looseness of a plurality of bolts and nuts for fixing two or more parts, and has a plurality of holes through which the bolts are inserted.
  • a first conductive layer that is electrically connected to any of the neck of the bolt, the surface of the component on one side, and the surface of the component on the other side, and the first conductive layer laminated with the first conductive layer.
  • a non-conductive layer having the same planar shape and the non-conductive layer are arranged so as to face the first conductive layer with the non-conductive layer interposed therebetween, and electrically with any of the surface of the component, the surface of the component of the other, and the nut.
  • the gist is to provide a second conductive layer connected to the above.
  • the method for identifying a loose bolt is to use a ring-shaped looseness detection sensor and a looseness detection device for detecting looseness of a plurality of bolts and nuts for fixing two or more parts.
  • a method of identifying a loose bolt that identifies a bolt, with multiple holes through which the bolt is inserted, with either the neck of the bolt, the surface of one of the parts, or the surface of the other part.
  • the hole of the first conductive layer electrically connected or the second conductive layer having the same shape as the non-conductive layer facing the first conductive layer with the non-conductive layer having the same shape as the first conductive layer sandwiched between them.
  • a high-frequency sweep step that sweeps and feeds a high-frequency signal having a frequency in a predetermined range at a position different from the center of each of the above, a resonance frequency detection step that detects the resonance frequency of the looseness detection sensor, and the resonance frequency.
  • the resonance frequency recording step that records the resonance frequency detected in the detection step is compared with the resonance frequency detected in the resonance frequency detection step and the past resonance frequency, and the presence or absence of a new resonance frequency or the amount of change in the resonance frequency is determined.
  • the loosened bolt is specified based on the presence or absence of a new resonance frequency or the amount of change in the resonance frequency.
  • the gist is to perform specific steps.
  • a looseness detection sensor suitable for inspecting looseness of a tightened portion of two or more parts by a plurality of bolts and a method for identifying loose bolts.
  • FIG. 1 It is a side view schematically showing how the looseness detection sensor which concerns on embodiment of this invention is fixed to a component. It is a structural cross-sectional view of the fixing part of a bolt-nut shown in FIG. It is a schematic diagram which shows the looseness detection sensor and the looseness detection device shown in FIG. 1. It is a top view which shows an example of the plane of the looseness detection sensor which concerns on embodiment of this invention. It is a figure which shows the example which measured the reflected wave by propagating an electromagnetic wave from the feeding point ⁇ shown in FIG. It is a figure which shows the example which measured the reflected wave by propagating an electromagnetic wave from the feeding point ⁇ shown in FIG. It is a block diagram which shows the functional structure example of the looseness detection apparatus shown in FIG.
  • FIG. 1 is a side view schematically showing an example of a looseness detection sensor according to an embodiment of the present invention.
  • the looseness detection sensor 3 shown in FIG. 1 is an annular sensor that detects looseness of a plurality of bolts and nuts that fix two or more parts 1 and 2.
  • FIG. 1 shows an example of fixing the flanges 1F and 2F of parts 1 and 2 which are pipes with four bolts 4.
  • the number of bolts 4 and the shape and number of parts to be fixed are not limited to this example.
  • the notation of the washer arranged between the neck portion of the bolt 4 and the looseness detection sensor 3 or the surface of the flange 2F of the component 2 and the nut 6 is omitted.
  • the looseness detection sensor 3 is arranged, for example, on the surface of the flange 1F on the component 1 side.
  • the looseness detection sensor 3 may be arranged between the flange 1F and the flange 2F, or on the surface of the flange 2F on the component 2 side.
  • FIG. 2 is a structural cross-sectional view of the fixed portion of the bolt 4-nut 6 shown in FIG.
  • the cross section shown in FIG. 2 shows the neck portion 4a of the bolt 4, the washer 5, the loosening detection sensor 3, the flange 1F, the flange 2F, the washer 5, and the nut 6 from the left.
  • the bolt 4 is inserted into the holes H formed in the flanges 1F and 2F of both, and the nut 6 is fitted and fixed to the threaded portion 4c of the bolt 4 protruding to the opposite side. ..
  • the washer 5 may be omitted.
  • the looseness detection sensor 3 may be arranged so as to be in contact with the surface of the flange 2F on the component 2 side. Further, it may be arranged between the flanges 1F and 2F.
  • the looseness detection sensor 3 is configured by laminating three layers of a first conductive layer 3a, a non-conductive layer 3b, and a second conductive layer 3c.
  • the first conductive layer 3a is perforated with a plurality of holes through which the bolt 4 is inserted, and is electrically connected to any of the neck portion 4a of the bolt 4, the surface of one component 1, and the surface of the other component 2. That is, the looseness detection sensor 3 may be arranged at any position on the surface of the flange 1F, between the flanges 1F and 2F, and on the surface of the flange 2F on the component 2 side.
  • the first conductive layer 3a is made of a material such as steel, iron, or copper.
  • the non-conductive layer 3b is laminated with the first conductive layer 3a and has the same planar shape as the first conductive layer 3a.
  • the non-conductive layer 3b is made of, for example, a resin such as polyethylene terephthalate (PET), a fluorine resin (PTFE), a polyimide (PI), and a material such as crow epoxy (FR-4).
  • the second conductive layer 3c has the same planar shape as the first conductive layer 3a, and is electrically connected to any of the surface of one component 1, the surface of the other component 2, and the nut 6.
  • the material of the second conductive layer 3c is the same as that of the first conductive layer 3a.
  • the second conductive layer 3c may be omitted.
  • the second conductive layer 3c may be omitted as long as the surface of the flange 2F on the flange 1F side is not insulated by paint or the like. In that case, the flange 2F acts as the second conductive layer 3c. That is, the second conductive layer 3c can be replaced with the component 2 whose surface is not insulated.
  • the neck portion 4a of the bolt 4 does not come into direct contact with the component 1. Further, since the diameter of the bolt 4 is smaller than the diameter of the hole H, normally, the bolt 4 and the parts 1 and 2 do not electrically conduct with each other. If the bolt 4 is inserted eccentrically with respect to the hole H, the bolt 4 may come into contact with the hole H. If such a thing is assumed, the lower neck portion (hereinafter, the shaft) 4b of the bolt 4 may be coated.
  • the bolt 4 and the parts 1 and 2 should not be directly connected.
  • the bolt 4 and the parts 1 and 2 are electrically conductive via the nut 6.
  • the conductor is conducted through the path of the first conductive layer 3a, the bolt 4, the nut 6, the part 2, the part 1, and the second conductive layer 3c. The same applies to the other bolts 4.
  • FIG. 3 is a diagram schematically showing a looseness detection sensor 3 according to the present embodiment and a looseness detection device 100 for detecting looseness of a bolt 4.
  • the looseness detection device 100 sweeps and feeds a high frequency signal having a frequency in a predetermined range to the looseness detection sensor 3 and the components 1 and 2, and detects a change in the resonance frequency of the high frequency signal propagating in the above path.
  • the fed high frequency signal matches the resonance frequency of the above path, it is confined in the non-conductive layer 3b.
  • the frequency (resonance frequency) of the high frequency signal confined in the non-conductive layer 3b changes depending on the degree of looseness of the bolt 4. That is, the loose bolt 4 can be identified from the change in the resonance frequency.
  • FIG. 4 is a diagram showing a plane of the looseness detection sensor 3.
  • FIG. 4 shows an example in which four bolts 4 are inserted into holes 3 1 H, holes 3 2 H, holes 3 3 H, and holes 3 4 H, respectively, and are fixed as shown in FIG. ⁇ and ⁇ represent the positions of feeding points to which high-frequency signals are fed.
  • bolt 4 1 represents a bolt inserted through hole 3 1 H.
  • FIG. 5 is a diagram showing an example in which an electromagnetic wave is propagated from a feeding point ⁇ and a reflected wave is measured.
  • the horizontal direction represents the frequency and the vertical direction represents the resonance strength.
  • the frequency at which the resonance intensity drops downward represents the resonance frequency. The lower the resonance strength, the stronger the resonance.
  • the characteristic shown by the solid line in FIG. 5 represents the resonance characteristic in a state where all four bolts 4 are squeezed. Resonance near the center of the scanning range of the high frequency signal is weak when all four bolts 4 are throttled.
  • the characteristic shown by the alternate long and short dash line represents the resonance characteristic in a state where only the bolt 42 is loosened.
  • the resonance near the center of the scanning range of the high-frequency signal is slightly stronger than that in the state where all four bolts 4 are throttled (solid line).
  • the characteristic shown by the broken line represents the resonance characteristic in the state where only the bolt 43 is loosened.
  • the resonance near the center of the scanning range of the high frequency signal is quite strong.
  • the loose bolt 4 can be specified based on the difference in resonance characteristics.
  • the resonance characteristic when the electromagnetic wave is propagated from the feeding point ⁇ is the same when the bolt 4 2 or the bolt 4 4 is loosened. This is because the distance to the feeding point ⁇ is the same for the bolt 4 4 and the bolt 4 2 .
  • the feeding points may be arranged at positions where the distances from the centers of the plurality of bolts 4 are different.
  • the feeding point ⁇ shown in FIG. 4 is a position where the distance connecting the centers of the bolts 4 3 and 4 is divided into 3: 1.
  • the distance between the feeding point ⁇ and the center of each bolt 4 1 to 4 4 is different.
  • the division between the bolts 4 is not limited to 3: 1.
  • the division may be 5: 1 or 7: 1.
  • FIG. 6 shows the resonance intensity when the electromagnetic wave is propagated to the feeding point ⁇ shown in FIG.
  • the characteristic of the alternate long and short dash line represents the resonance strength in the state where only the bolt 42 is loosened.
  • the characteristic of the broken line represents the resonance strength in the state where only the bolt 44 is loosened.
  • the looseness detection sensor 3 is a ring-shaped sensor that detects looseness of a plurality of bolts 4 and nuts 6 for fixing two or more parts 1 and 2, and is a bolt.
  • a first conductive layer 3a through which a plurality of holes H through which the 4 is inserted are opened and electrically connected to any of the neck portion 4a of the bolt 4, the surface of one component 1, and the surface of the other component 2, and the first.
  • FIG. 7 is a block diagram showing a functional configuration example of the looseness detection device according to the embodiment of the present invention.
  • the looseness detection device 100 shown in FIG. 7 includes a frequency sweep unit 20, a high frequency feeding unit 21, a resonance frequency detection unit 22, a resonance frequency recording unit 23, a determination unit 24, a specific unit 25, and a control unit 26.
  • the control unit 26 is a function configuration unit that controls the operation of each function configuration unit, and can be configured by, for example, a computer including a ROM, a RAM, a CPU, and the like.
  • a part of the resonance frequency detection unit 22, the resonance frequency recording unit 23, the determination unit 24, and the specific unit 25 can also be configured by the computer.
  • the frequency sweep unit 20 sweeps frequencies in a predetermined range.
  • the frequency in the predetermined range varies depending on the size of the two parts 1 and 2 (the size of the looseness detection sensor 3), the number of bolts 4 to be fixed, the material of the non-conductive layer 3b, and the like, for example, in the range of 1 GHz to 2 GHz. Is.
  • the frequency sweeping unit 20 sweeps the frequency between the start frequency and the stop frequency each time the process of detecting the looseness of the bolt is performed.
  • the high frequency feeding unit 21 generates a high frequency signal having a frequency swept by the frequency sweeping unit 20, and feeds the generated high frequency signal to the feeding points ⁇ and ⁇ of the detection sensor 3.
  • the feeding is performed by the operator operating the tip of the probe (not shown) to bring it into contact with the feeding points ⁇ and ⁇ .
  • the resonance frequency detection unit 22 detects the resonance frequency of the parts 1 and 2 to which the looseness detection sensor 3 is attached.
  • the resonance frequency can be obtained by performing a fast Fourier (FFT) transform on the high frequency current flowing through the looseness detection sensor 3.
  • FFT fast Fourier
  • the reflected wave reflected from the looseness detection sensor 3 may be fast Fourier transformed to detect the resonance frequency.
  • the resonance frequency detection unit 22 is connected in series between the feeding points ⁇ and ⁇ and the resonance frequency recording unit 23 (not shown). Specific examples of the resonance frequency will be described later.
  • the resonance frequency recording unit 23 records the resonance frequency detected by the resonance frequency detection unit 22.
  • the resonance frequency can be obtained from the peak value of the frequency spectrum of, for example, the reflected wave between the start frequency and the stop frequency. Alternatively, it may be obtained from the peak value of the frequency spectrum of the high frequency current flowing through the looseness detection sensor 3.
  • the determination unit 24 compares the obtained peak value with the peak value obtained in the past, and has the presence or absence of a new resonance frequency or the presence or absence of loosening of the bolts 4 1 to 4 based on the amount of change in the resonance frequency. Is determined.
  • the identification unit 25 identifies the loosened bolt based on the presence or absence of the resonance frequency or the amount of change in the resonance frequency. Specific examples for specifying the bolt will be described later.
  • FIG. 8 is a flowchart showing a processing procedure of a loose bolt identification method executed by the loosening detection device 100.
  • a method for specifying a loose bolt according to the present embodiment is a high frequency sweep step S1, a resonance frequency detection step S2, a resonance frequency recording step S3, a determination step S4, and a specific step S5.
  • the high frequency sweep step S1 sweeps and feeds a high frequency signal having a frequency within a predetermined range to the feeding points ( ⁇ , ⁇ ) of the looseness detection sensor 3 attached to the coupling portion of the parts 1 and 2.
  • Resonance frequency detection step S2 detects the resonance frequency of the parts 1 and 2 to which the looseness detection sensor 3 is attached.
  • Resonance frequency recording step S3 records the resonance frequency detected in resonance frequency detection step S2.
  • the resonance frequency detected in the resonance frequency detection step S2 and the past resonance frequency (resonance frequency recorded in the resonance frequency recording step S3) are compared, and the presence or absence of a new resonance frequency or the amount of change in the resonance frequency is obtained. It is determined whether or not the bolt 4 is loose based on the above.
  • the loose bolt 4 is specified based on the presence or absence of a new resonance frequency or the amount of change in the resonance frequency.
  • a ring-shaped looseness detection sensor 3 and a looseness detection device 100 for detecting looseness of a plurality of bolts and nuts for fixing two or more parts are used.
  • a method of identifying a loose bolt using a method of identifying a loose bolt in which a plurality of holes H through which the bolt 4 is inserted are formed, the neck portion 4a of the bolt 4, the surface of one component 1 and the other component 2 are opened.
  • the high frequency sweep step S1 for sweeping and feeding a high frequency signal having a frequency in a predetermined range and the resonance frequency of the looseness detection sensor 3 are set at positions where the distances from the centers of the plurality of holes of the second conductive layer 3c are different.
  • the resonance frequency detection step S2 to be detected, the resonance frequency recording step S3 to record the resonance frequency detected in the resonance frequency detection step S2, and the resonance frequency detected in the resonance frequency detection step S2 and the past resonance frequency are compared.
  • a specific step S5 for specifying the loosened bolt 4 based on the amount of change in the resonance frequency is performed. This makes it possible to identify the loose bolt 4.
  • FIG. 9 is a diagram showing a specific example of identifying a loosened bolt using the loosening detection sensor 3 according to the present embodiment.
  • the horizontal direction of FIG. 9 is the frequency, and the vertical direction is the resonance intensity, which is the same as that of FIG.
  • the looseness detection sensor 3 of the specific example was fixed to the surface of the flange with four bolts 4 as shown in FIG.
  • the outer radius of the first conductive layer 3a, the non-conductive layer 3b, and the second conductive layer 3c was 57.5 mm
  • the inner radius was 33 mm
  • the radius of the hole H was 7.5 mm
  • the radius of the shaft 4b was 7 mm.
  • the thickness of the first and second conductive layers 3a and 3c was set to 2 mm
  • the thickness of the non-conductive layers 3b was set to 0.4 mm.
  • the characteristic shown by the solid line in FIG. 9 represents the resonance characteristic in a state where all four bolts 4 are squeezed.
  • the high-frequency signal generated by the high-frequency feeding unit 21 of the looseness detection device 100 was input to a position corresponding to the feeding point ⁇ (FIG. 4) via the probe.
  • the characteristic shown by the long dashed line is the state where the bolt 4 1 is loosened
  • the characteristic shown by the alternate long and short dash line is the state where the bolt 4 2 is loosened
  • the characteristic shown by the broken line is the state where the bolt 4 3 is loosened
  • the characteristic shown by the dotted line is.
  • the positions of the loosened bolts 4 1 to 44 can be specified from the difference in resonance characteristics.
  • the feeding points ⁇ and ⁇ are a part of the first conductive layer 3a or the second conductive layer 3c to which the high frequency signal generated by the high frequency feeding unit 21 of the loosening detection device 100 is fed.
  • the feeding points ⁇ and ⁇ may be configured by micro split lines.
  • FIG. 10 is a diagram schematically showing a plane in which the feeding point ⁇ is composed of microsplit lines.
  • the micro split line has a structure in which a linear conductor foil 31 is formed on the surface of a non-conductive layer 3b having a conductor foil formed on the back surface.
  • the micro split line makes it easy to adjust the characteristic impedance. Therefore, the electromagnetic wave can be efficiently input to the looseness detection sensor 3.
  • the feeding points ⁇ and ⁇ may be configured by microsplit lines projecting to the outside of the ring shape of the looseness detection sensor 3. Further, the feeding points configured by the micro split line may be arranged at two or more different positions. By changing the position of the feeding point, the accuracy of identifying loose bolts can be improved.
  • a SMA type coaxial connector may be arranged at the tip of the conductor foil 31, and a high frequency signal may be input to the looseness detection sensor 3 via a coaxial cable (not shown).
  • the looseness detection sensor 3 As described above, according to the looseness detection sensor 3 according to the present embodiment and the method for identifying loose bolts using the same, it is possible to detect looseness of a plurality of bolts and nuts for fixing two parts.
  • the inspection result can be obtained quantitatively. Further, if the looseness detection sensor 3 and the looseness detection device 100 are arranged apart from each other, the looseness of the bolt 4 can be detected remotely.
  • the looseness detection sensor 3 and the looseness detection device 100 may be connected by a high frequency signal line such as a micro split line.
  • the loosening detection device 100 may be arranged in the vicinity of the bolt 4 at the important part of the structure so that the detection result is transmitted wirelessly. By doing so, the risks associated with the inspection can be eliminated. It is also possible to reduce inspection costs.
  • the looseness detection sensor 3 of the present invention has shown an example in which pipes 1 and 2 provided with flanges 1F and 2F are fixed to each other with bolts 4 and nuts 6, but the present invention is not limited to this example.
  • the looseness detection sensor 3 can also be used when fixing other parts to each other.
  • the number of bolts 4 is not limited to the above embodiment.
  • the present invention is not limited to the above embodiment, and can be modified within the scope of the gist thereof.
  • Looseness detection sensor 3a First conductive layer 3b: Non-conductive layer 3c: Second conductive layer 4: Bolt 5: Washer 6: Nut 100: Looseness detection device 20: Frequency sweeping unit 21: High frequency power supply Unit 22: Resonance frequency detection unit 23: Resonance frequency recording unit 24: Judgment unit 25: Specific unit 26: Control unit ⁇ , ⁇ : Feed point

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Abstract

A ring-shaped sensor for detecting looseness of a plurality of bolts 4 and nuts 6 that fix two or more components, said sensor comprising: a first conductive layer 3a that has a plurality of holes H through which the bolts 4 are passed, and that is electrically connected to any of the neck part 41a of the bolts 41, the surface of one component 1, and the surface of the other component 2; a non-conductive layer 3b that is laminated to the first conductive layer 3a and has the same planar shape as the first conductive layer 3a; and a second conductive layer 3c that is disposed oppositely from the first conductive layer 3a with the non-conductive layer 3b therebetween, and that is electrically connected to any of the surface of the one component 1, the surface of the other component 2, and the nuts 6.

Description

緩み検出センサと緩んだボルトの特定方法Looseness detection sensor and how to identify loose bolts
　本発明は、二つ以上の部品を固定するボルトの緩みを検出する緩み検出センサと緩んだボルトの特定方法に関する。 The present invention relates to a looseness detection sensor that detects looseness of bolts that fix two or more parts, and a method of identifying loose bolts.
　ボルトは、部品と部品を締め付け、固定するものであり、インフラ構造物、プラント設備等の大型設備から、乗り物、遊具、及び家具等の身近な製品まで様々な用途で使用される。ボルトの接合部では、振動や過大な力による組成変形、疲労等の劣化が原因で、緩みや脱落が生じることがある。 Bolts are used to tighten and fix parts to parts, and are used for various purposes from large equipment such as infrastructure structures and plant equipment to familiar products such as vehicles, playsets, and furniture. At the bolt joint, loosening or falling off may occur due to deterioration such as composition deformation and fatigue due to vibration or excessive force.
　これらが原因で、例えば橋梁の崩落事故、接合部分からのガス及び液体の漏洩、遊具の破損、高所からの落下物による人身事故等が発生する。これらの事故を防止するため、ボルトにマーキングをして、合いマークのズレを監視する方法、打音検査、及び超音波を利用した検査方法（非特許文献１）等の検査方法が存在する。 Due to these factors, for example, a bridge collapse accident, gas and liquid leakage from a joint, damage to playsets, personal injury due to a fallen object from a high place, etc. occur. In order to prevent these accidents, there are inspection methods such as a method of marking a bolt to monitor the deviation of the matching mark, a tapping sound inspection, and an inspection method using ultrasonic waves (Non-Patent Document 1).
　しかしながら、合いマークのズレを監視する方法、及び打音検査は、検査対象が見難い場所にあったり、遠方であったりで目視点検が困難な部分の検査には適さない。また、熟練が必要であり、未熟練者による検査は難しいという課題がある。 However, the method of monitoring the deviation of the matching mark and the tapping sound inspection are not suitable for the inspection of the part where the inspection target is difficult to see or the inspection target is far away and it is difficult to visually inspect. In addition, there is a problem that skill is required and inspection by an unskilled person is difficult.
　また、超音波を利用した検査方法は、高所等の作業性の悪い場所に計測器を運んで検査するのでコストが高くなる。また、危険であるという課題がある。このように、ボルトによる二つの部品の締め付け部分の緩みを検査するのに好適なもの、及び方法が存在しないという課題がある。 In addition, the inspection method using ultrasonic waves is costly because the measuring instrument is carried to a place with poor workability such as a high place for inspection. There is also the problem of being dangerous. As described above, there is a problem that there is no suitable method and method for inspecting looseness of the tightened portion of the two parts by the bolt.
　本発明は、この課題に鑑みてなされたものであり、複数のボルトによる二つ以上の部品の締め付け部分の緩みを検査するのに好適な緩み検出センサと緩んだボルトの特定方法を提供することを目的とする。 The present invention has been made in view of this subject, and provides a looseness detection sensor suitable for inspecting looseness of a tightened portion of two or more parts by a plurality of bolts, and a method for identifying loosened bolts. With the goal.
　本発明の一態様に係る緩み検出センサは、二つ以上の部品を固定する複数のボルトとナットの緩みを検出する円環形状のセンサであって、前記ボルトが挿通される複数の孔が開けられ、前記ボルトの首部、一方の前記部品の表面、及び他方の前記部品の表面の何れかと電気的に接続される第１導電層と、前記第１導電層と積層され該第１導電層と同じ平面形状の非導電層と、前記非導電層を挟んで前記第１導電層と対向して配置され、一方の前記部品の表面、他方の前記部品の表面、及び前記ナットの何れかと電気的に接続される第２導電層とを備えることを要旨とする。 The looseness detection sensor according to one aspect of the present invention is a ring-shaped sensor that detects looseness of a plurality of bolts and nuts for fixing two or more parts, and has a plurality of holes through which the bolts are inserted. A first conductive layer that is electrically connected to any of the neck of the bolt, the surface of the component on one side, and the surface of the component on the other side, and the first conductive layer laminated with the first conductive layer. A non-conductive layer having the same planar shape and the non-conductive layer are arranged so as to face the first conductive layer with the non-conductive layer interposed therebetween, and electrically with any of the surface of the component, the surface of the component of the other, and the nut. The gist is to provide a second conductive layer connected to the above.
　また、本発明の一態様に係る緩んだボルトの特定方法は、二つ以上の部品を固定する複数のボルトとナットの緩みを検出する円環形状の緩み検出センサと緩み検出装置を用いて緩んだボルトを特定する緩んだボルトの特定方法であって、前記ボルトが挿通される複数の孔が開けられ、前記ボルトの首部、一方の前記部品の表面、及び他方の前記部品の表面の何れかと電気的に接続される第１導電層又は、該第１導電層と同形状の非導電層を挟んで前記第１導電層と対向する前記非導電層と同形状の第２導電層の前記孔のそれぞれの中心からの距離が異なる位置に、所定の範囲の周波数の高周波信号を掃引して給電する高周波掃引ステップと、前記緩み検出センサの共振周波数を検出する共振周波数検出ステップと、前記共振周波数検出ステップで検出された共振周波数を記録する共振周波数記録ステップと、前記共振周波数検出ステップで検出された共振周波数と過去の共振周波数を比較し、新たな共振周波数の有無又は共振周波数の変化量に基づいて前記ボルトの緩みの有無を判定する判定ステップと、前記判定ステップで緩みが有ると判定された場合に、新たな共振周波数の有無又は共振周波数の変化量に基づいて緩んだボルトを特定する特定ステップとを行うことを要旨とする。 Further, the method for identifying a loose bolt according to one aspect of the present invention is to use a ring-shaped looseness detection sensor and a looseness detection device for detecting looseness of a plurality of bolts and nuts for fixing two or more parts. A method of identifying a loose bolt that identifies a bolt, with multiple holes through which the bolt is inserted, with either the neck of the bolt, the surface of one of the parts, or the surface of the other part. The hole of the first conductive layer electrically connected or the second conductive layer having the same shape as the non-conductive layer facing the first conductive layer with the non-conductive layer having the same shape as the first conductive layer sandwiched between them. A high-frequency sweep step that sweeps and feeds a high-frequency signal having a frequency in a predetermined range at a position different from the center of each of the above, a resonance frequency detection step that detects the resonance frequency of the looseness detection sensor, and the resonance frequency. The resonance frequency recording step that records the resonance frequency detected in the detection step is compared with the resonance frequency detected in the resonance frequency detection step and the past resonance frequency, and the presence or absence of a new resonance frequency or the amount of change in the resonance frequency is determined. Based on the determination step for determining the presence or absence of looseness of the bolt, and when it is determined that there is looseness in the determination step, the loosened bolt is specified based on the presence or absence of a new resonance frequency or the amount of change in the resonance frequency. The gist is to perform specific steps.
　本発明によれば、複数のボルトによる二つ以上の部品の締め付け部分の緩みを検査するのに好適な緩み検出センサと緩んだボルトの特定方法を提供することができる。 According to the present invention, it is possible to provide a looseness detection sensor suitable for inspecting looseness of a tightened portion of two or more parts by a plurality of bolts and a method for identifying loose bolts.
本発明の実施形態に係る緩み検出センサが部品に固定されている様子を模式的に示す側面図である。It is a side view schematically showing how the looseness detection sensor which concerns on embodiment of this invention is fixed to a component. 図１に示すボルト－ナットの固定部分の構造断面図である。It is a structural cross-sectional view of the fixing part of a bolt-nut shown in FIG. 図１に示す緩み検出センサと緩み検出装置を示す模式図である。It is a schematic diagram which shows the looseness detection sensor and the looseness detection device shown in FIG. 1. 本発明の実施形態に係る緩み検出センサの平面の一例を示す平面図である。It is a top view which shows an example of the plane of the looseness detection sensor which concerns on embodiment of this invention. 図４に示す給電点αから電磁波を伝搬させて反射波を計測した例を示す図である。It is a figure which shows the example which measured the reflected wave by propagating an electromagnetic wave from the feeding point α shown in FIG. 図４に示す給電点βから電磁波を伝搬させて反射波を計測した例を示す図である。It is a figure which shows the example which measured the reflected wave by propagating an electromagnetic wave from the feeding point β shown in FIG. 図３に示す緩み検出装置の機能構成例を示すブロック図である。It is a block diagram which shows the functional structure example of the looseness detection apparatus shown in FIG. 緩み検出装置１００が実行する緩んだボルトの特定方法の処理手順を示すフローチャートである。It is a flowchart which shows the processing procedure of the method of identifying a loose bolt executed by a looseness detection apparatus 100. 緩み検出センサで検出した共振特性の例を示す図である。It is a figure which shows the example of the resonance characteristic detected by the looseness detection sensor. 図４に示す給電点βをマイクロスプリットラインで構成した緩み検出センサの平面を模式的に示す図である。It is a figure which shows typically the plane of the looseness detection sensor which configured the feeding point β shown in FIG. 4 by a microsplit line.
　以下、本発明の実施形態について図面を用いて説明する。複数の図面中同一のものには同じ参照符号を付し、説明は繰り返さない。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same reference numerals are given to the same objects in a plurality of drawings, and the description is not repeated.
　（緩み検出センサ）
　図１は、本発明の実施形態に係る緩み検出センサの一例を模式的に示す側面図である。図１に示す緩み検出センサ３は、二つ以上の部品１，２を固定する複数のボルトとナットの緩みを検出する円環形状のセンサである。 (Loose detection sensor)
FIG. 1 is a side view schematically showing an example of a looseness detection sensor according to an embodiment of the present invention. The looseness detection sensor 3 shown in FIG. 1 is an annular sensor that detects looseness of a plurality of bolts and nuts that fix two or more parts 1 and 2.
　図１は、パイプである部品１，２のそれぞれのフランジ１Ｆ，２Ｆの部分を4つのボルト４で固定する例を示す。ボルト４の数、及び固定する部品の形状及び数はこの例に限定されない。図１において、ボルト４の首部と緩み検出センサ３、又は部品２のフランジ２Ｆの表面とナット６の間に配置される座金の表記は省略している。 FIG. 1 shows an example of fixing the flanges 1F and 2F of parts 1 and 2 which are pipes with four bolts 4. The number of bolts 4 and the shape and number of parts to be fixed are not limited to this example. In FIG. 1, the notation of the washer arranged between the neck portion of the bolt 4 and the looseness detection sensor 3 or the surface of the flange 2F of the component 2 and the nut 6 is omitted.
　緩み検出センサ３は、例えば、フランジ１Ｆの部品１側の表面に配置される。なお、緩み検出センサ３は、フランジ１Ｆとフランジ２Ｆの間、又はフランジ２Ｆの部品２側の表面に配置しても構わない。 The looseness detection sensor 3 is arranged, for example, on the surface of the flange 1F on the component 1 side. The looseness detection sensor 3 may be arranged between the flange 1F and the flange 2F, or on the surface of the flange 2F on the component 2 side.
　図２は、図１に示すボルト４－ナット６の固定部分の構造断面図である。図２に示す断面は、左からボルト４の首部４ａ、座金５、緩み検出センサ３、フランジ１Ｆ、フランジ２Ｆ、座金５、及びナット６を示す。部品１，２は、両者のフランジ１Ｆ，２Ｆに空けられた孔Ｈにボルト４が挿入され、反対側に突出したボルト４のねじが切られた部分４ｃにナット６が嵌められて固定される。なお、座金５は無くても構わない。また、緩み検出センサ３は、フランジ２Ｆの部品２側の表面に接触するように配置してもよい。また、フランジ１Ｆ，２Ｆの間に配置しても構わない。 FIG. 2 is a structural cross-sectional view of the fixed portion of the bolt 4-nut 6 shown in FIG. The cross section shown in FIG. 2 shows the neck portion 4a of the bolt 4, the washer 5, the loosening detection sensor 3, the flange 1F, the flange 2F, the washer 5, and the nut 6 from the left. In the parts 1 and 2, the bolt 4 is inserted into the holes H formed in the flanges 1F and 2F of both, and the nut 6 is fitted and fixed to the threaded portion 4c of the bolt 4 protruding to the opposite side. .. The washer 5 may be omitted. Further, the looseness detection sensor 3 may be arranged so as to be in contact with the surface of the flange 2F on the component 2 side. Further, it may be arranged between the flanges 1F and 2F.
　緩み検出センサ３は、第１導電層３ａ、非導電層３ｂ、及び第２導電層３ｃの3層が積層されて構成される。 The looseness detection sensor 3 is configured by laminating three layers of a first conductive layer 3a, a non-conductive layer 3b, and a second conductive layer 3c.
　第１導電層３ａは、ボルト４が挿通される複数の孔が開けられ、ボルト４の首部４ａ、一方の部品１の表面、及び他方の部品２の表面の何れかと電気的に接続される。つまり、緩み検出センサ３は、フランジ１Ｆの表面、フランジ１Ｆ，２Ｆの間、及びフランジ２Ｆの部品２側の表面の何れかの位置に配置してもよい。第１導電層３ａは、鋼材、鉄、銅等の材料で構成される。 The first conductive layer 3a is perforated with a plurality of holes through which the bolt 4 is inserted, and is electrically connected to any of the neck portion 4a of the bolt 4, the surface of one component 1, and the surface of the other component 2. That is, the looseness detection sensor 3 may be arranged at any position on the surface of the flange 1F, between the flanges 1F and 2F, and on the surface of the flange 2F on the component 2 side. The first conductive layer 3a is made of a material such as steel, iron, or copper.
　非導電層３ｂは、第１導電層３ａと積層され第１導電層３ａと同じ平面形状である。非導電層３ｂは、例えば、ポリエチレンテレフタレート（PET）、フッソ樹脂（PTFE）、ポリミイド(PI)等の樹脂、カラスエポキシ（FR-4）等の材料で構成される。 The non-conductive layer 3b is laminated with the first conductive layer 3a and has the same planar shape as the first conductive layer 3a. The non-conductive layer 3b is made of, for example, a resin such as polyethylene terephthalate (PET), a fluorine resin (PTFE), a polyimide (PI), and a material such as crow epoxy (FR-4).
　第２導電層３ｃは、第１導電層３ａと同じ平面形状であり、一方の部品１の表面、他方の部品２の表面、及びナット６の何れかと電気的に接続される。第２導電層３ｃの材料は、第１導電層３ａと同じである。 The second conductive layer 3c has the same planar shape as the first conductive layer 3a, and is electrically connected to any of the surface of one component 1, the surface of the other component 2, and the nut 6. The material of the second conductive layer 3c is the same as that of the first conductive layer 3a.
　なお、第２導電層３ｃは無くても構わない。フランジ２Ｆのフランジ１Ｆ側の表面が、塗料等で絶縁されてなければ第２導電層３ｃは無くてもよい。その場合は、フランジ２Ｆが第２導電層３ｃの作用を行う。つまり、第２導電層３ｃは、表面が絶縁されていない部品２に置き代えることが可能である。 The second conductive layer 3c may be omitted. The second conductive layer 3c may be omitted as long as the surface of the flange 2F on the flange 1F side is not insulated by paint or the like. In that case, the flange 2F acts as the second conductive layer 3c. That is, the second conductive layer 3c can be replaced with the component 2 whose surface is not insulated.
　図２に示すように、ボルト４の首部４ａは、直接、部品１に接触しない。また、ボルト４の径は、孔Ｈの径よりもが小さいので、通常、ボルト４と部品１，２は電気的に導通しない。なお、ボルト４が孔Ｈに対して偏心して挿入されると、ボルト４が孔Ｈと接触してしまう場合がある。そのような事が想定される場合は、ボルト４の首下部分（以降、軸）４ｂを被覆加工してもよい。 As shown in FIG. 2, the neck portion 4a of the bolt 4 does not come into direct contact with the component 1. Further, since the diameter of the bolt 4 is smaller than the diameter of the hole H, normally, the bolt 4 and the parts 1 and 2 do not electrically conduct with each other. If the bolt 4 is inserted eccentrically with respect to the hole H, the bolt 4 may come into contact with the hole H. If such a thing is assumed, the lower neck portion (hereinafter, the shaft) 4b of the bolt 4 may be coated.
　つまり、ボルト４と部品１，２は直接導通しないようにする。その結果、ボルト４と部品１，２は、ナット６を介して電気的に導通することになる。部品１，２の表面が導電体の場合は、第１導電層３ａ、ボルト４、ナット６、部品２、部品１、第２導電層３ｃの経路で導通する。他のボルト４も同様である。 That is, the bolt 4 and the parts 1 and 2 should not be directly connected. As a result, the bolt 4 and the parts 1 and 2 are electrically conductive via the nut 6. When the surface of the parts 1 and 2 is a conductor, the conductor is conducted through the path of the first conductive layer 3a, the bolt 4, the nut 6, the part 2, the part 1, and the second conductive layer 3c. The same applies to the other bolts 4.
　図３は、本実施形態に係る緩み検出センサ３と、ボルト４の緩みを検出する緩み検出装置１００を模式的に示す図である。緩み検出装置１００は、緩み検出センサ３及び部品１，２に、所定の範囲の周波数の高周波信号を掃引して給電し、上記の経路を伝搬する高周波信号の共振周波数の変化を検出する。給電された高周波信号は、上記の経路の共振周波数に一致すると非導電層３ｂに閉じ込められる。 FIG. 3 is a diagram schematically showing a looseness detection sensor 3 according to the present embodiment and a looseness detection device 100 for detecting looseness of a bolt 4. The looseness detection device 100 sweeps and feeds a high frequency signal having a frequency in a predetermined range to the looseness detection sensor 3 and the components 1 and 2, and detects a change in the resonance frequency of the high frequency signal propagating in the above path. When the fed high frequency signal matches the resonance frequency of the above path, it is confined in the non-conductive layer 3b.
　非導電層３ｂに閉じ込められる高周波信号の周波数（共振周波数）は、ボルト４の緩み具合によって変化する。つまり、共振周波数の変化から緩んだボルト４を特定することができる。 The frequency (resonance frequency) of the high frequency signal confined in the non-conductive layer 3b changes depending on the degree of looseness of the bolt 4. That is, the loose bolt 4 can be identified from the change in the resonance frequency.
　図４は、緩み検出センサ３の平面を示す図である。図４は、4本のボルト４が孔３１Ｈ、孔３２Ｈ、孔３３Ｈ、孔３４Ｈにそれぞれ挿通され、図２に示したように固定される例を示す。α，βは、高周波信号が給電される給電点の位置を表す。 FIG. 4 is a diagram showing a plane of the looseness detection sensor 3. FIG. 4 shows an example in which four bolts 4 are inserted into holes 3 1 H, holes 3 2 H, holes 3 3 H, and holes 3 4 H, respectively, and are fixed as shown in FIG. α and β represent the positions of feeding points to which high-frequency signals are fed.
　以降において、ボルト４の位置を特定する必要がある場合は、ボルト４の参照符号に添え字を付けて表記する。例えばボルト４１は、孔３１Ｈに挿通されるボルトを表す。 Hereinafter, when it is necessary to specify the position of the bolt 4, the reference code of the bolt 4 is described by adding a subscript. For example, bolt 4 1 represents a bolt inserted through hole 3 1 H.
　図５は、給電点αから電磁波を伝搬させて反射波を計測した例を示す図である。図５の横方向は周波数、縦方向は共振強度を表す。共振強度が下に落ち込んでいる周波数が共振周波数を表す。共振強度が下に落ち込むほど強い共振であることを表す。 FIG. 5 is a diagram showing an example in which an electromagnetic wave is propagated from a feeding point α and a reflected wave is measured. In FIG. 5, the horizontal direction represents the frequency and the vertical direction represents the resonance strength. The frequency at which the resonance intensity drops downward represents the resonance frequency. The lower the resonance strength, the stronger the resonance.
　図５に実線で示す特性は、4本のボルト４が全て絞められた状態の共振特性を表す。高周波信号の走査範囲の中央付近の共振は、4本のボルト４が全て絞められた状態では弱い。 The characteristic shown by the solid line in FIG. 5 represents the resonance characteristic in a state where all four bolts 4 are squeezed. Resonance near the center of the scanning range of the high frequency signal is weak when all four bolts 4 are throttled.
　一点鎖線で示す特性は、ボルト４２のみが緩んだ状態の共振特性を表す。高周波信号の走査範囲の中央付近の共振は、4本のボルト４が全て絞められた状態（実線）よりもやや強い。 The characteristic shown by the alternate long and short dash line represents the resonance characteristic in a state where only the bolt 42 is loosened. The resonance near the center of the scanning range of the high-frequency signal is slightly stronger than that in the state where all four bolts 4 are throttled (solid line).
　破線で示す特性は、ボルト４３のみが緩んだ状態の共振特性を表す。高周波信号の走査範囲の中央付近の共振はかなり強い。 The characteristic shown by the broken line represents the resonance characteristic in the state where only the bolt 43 is loosened. The resonance near the center of the scanning range of the high frequency signal is quite strong.
　このように共振特性の差に基づいて緩んだボルト４を特定することができる。但し、給電点αから電磁波を伝搬させた場合の共振特性は、ボルト４２、又はボルト４４が緩んだ状態では同じである。これは、給電点αとの距離がボルト４４とボルト４２で同じだからである。 In this way, the loose bolt 4 can be specified based on the difference in resonance characteristics. However, the resonance characteristic when the electromagnetic wave is propagated from the feeding point α is the same when the bolt 4 2 or the bolt 4 4 is loosened. This is because the distance to the feeding point α is the same for the bolt 4 4 and the bolt 4 2 .
　したがって、給電点は、複数のボルト４のそれぞれの中心からの距離が異なる位置に配置するとよい。図４に示す給電点βは、ボルト４３と４４の中心を結ぶ距離を3：1に分割した位置である。 Therefore, the feeding points may be arranged at positions where the distances from the centers of the plurality of bolts 4 are different. The feeding point β shown in FIG. 4 is a position where the distance connecting the centers of the bolts 4 3 and 4 is divided into 3: 1.
　給電点βと、各ボルト４１～４４の中心との距離はそれぞれ異なる。なお、ボルト４の間の分割は、3：1に限られない。分割は、5：1でも7：1でも構わない。 The distance between the feeding point β and the center of each bolt 4 1 to 4 4 is different. The division between the bolts 4 is not limited to 3: 1. The division may be 5: 1 or 7: 1.
　図６は、図４に示す給電点βに電磁波を伝搬させた場合の共振強度を示す。一点鎖線の特性は、ボルト４２のみが緩んだ状態の共振強度を表す。破線の特性は、ボルト４４のみが緩んだ状態の共振強度を表す。図６に示すように、給電点βに電磁波を伝搬させた場合は、ボルト４２とボルト４４の識別が可能である。 FIG. 6 shows the resonance intensity when the electromagnetic wave is propagated to the feeding point β shown in FIG. The characteristic of the alternate long and short dash line represents the resonance strength in the state where only the bolt 42 is loosened. The characteristic of the broken line represents the resonance strength in the state where only the bolt 44 is loosened. As shown in FIG. 6, when the electromagnetic wave is propagated to the feeding point β, it is possible to distinguish between the bolt 42 and the bolt 44 .
　以上説明したように、本実施形態に係る緩み検出センサ３は、二つ以上の部品１，２を固定する複数のボルト４とナット６の緩みを検出する円環形状のセンサであって、ボルト４が挿通される複数の孔Ｈが開けられ、ボルト４の首部４ａ、一方の部品１の表面、及び他方の部品２の表面の何れかと電気的に接続される第１導電層３ａと、第１導電層３ａと積層され、該第１導電層３ａと同じ平面形状の非導電層３ｂと、非導電層３ｂを挟んで第１導電層３ａと対向して配置され、一方の部品１の表面、他方の部品２の表面、及びナット６の何れかと電気的に接続される第２導電層３ｃとを備える。これにより、複数のボルトによる二つ以上の部品の締め付け部分の緩みを検査するのに好適な緩み検出センサ３を提供することができる。 As described above, the looseness detection sensor 3 according to the present embodiment is a ring-shaped sensor that detects looseness of a plurality of bolts 4 and nuts 6 for fixing two or more parts 1 and 2, and is a bolt. A first conductive layer 3a through which a plurality of holes H through which the 4 is inserted are opened and electrically connected to any of the neck portion 4a of the bolt 4, the surface of one component 1, and the surface of the other component 2, and the first. A non-conductive layer 3b having the same planar shape as the first conductive layer 3a, which is laminated with the first conductive layer 3a, is arranged so as to face the first conductive layer 3a with the non-conductive layer 3b interposed therebetween. , The surface of the other component 2, and a second conductive layer 3c that is electrically connected to any of the nuts 6. Thereby, it is possible to provide a looseness detection sensor 3 suitable for inspecting looseness of a tightened portion of two or more parts by a plurality of bolts.
　（緩み検出装置）
　図７は、本発明の実施形態に係る緩み検出装置の機能構成例を示すブロック図である。 (Loose detection device)
FIG. 7 is a block diagram showing a functional configuration example of the looseness detection device according to the embodiment of the present invention.
　図７に示す緩み検出装置１００は、周波数掃引部２０、高周波給電部２１、共振周波数検出部２２、共振周波数記録部２３、判定部２４、特定部２５、及び制御部２６を備える。制御部２６は、各機能構成部の動作を制御する機能構成部であり、例えば、ＲＯＭ、ＲＡＭ、ＣＰＵ等からなるコンピュータで構成することができる。制御部２６をコンピュータで実現する場合は、共振周波数検出部２２の一部、共振周波数記録部２３、判定部２４、及び特定部２５もそのコンピュータで構成することが可能である。 The looseness detection device 100 shown in FIG. 7 includes a frequency sweep unit 20, a high frequency feeding unit 21, a resonance frequency detection unit 22, a resonance frequency recording unit 23, a determination unit 24, a specific unit 25, and a control unit 26. The control unit 26 is a function configuration unit that controls the operation of each function configuration unit, and can be configured by, for example, a computer including a ROM, a RAM, a CPU, and the like. When the control unit 26 is realized by a computer, a part of the resonance frequency detection unit 22, the resonance frequency recording unit 23, the determination unit 24, and the specific unit 25 can also be configured by the computer.
　周波数掃引部２０は、所定の範囲の周波数を掃引する。所定の範囲の周波数は、二つの部品１，２の大きさ（緩み検出センサ３の大きさ）、固定するボルト４の数、及び非導電層３ｂの材質等によって異なり、例えば1GHz～2GHzの範囲である。周波数掃引部２０は、ボルトの緩みを検出する処理を行うたびに、スタート周波数とストップ周波数の間で周波数を掃引する。 The frequency sweep unit 20 sweeps frequencies in a predetermined range. The frequency in the predetermined range varies depending on the size of the two parts 1 and 2 (the size of the looseness detection sensor 3), the number of bolts 4 to be fixed, the material of the non-conductive layer 3b, and the like, for example, in the range of 1 GHz to 2 GHz. Is. The frequency sweeping unit 20 sweeps the frequency between the start frequency and the stop frequency each time the process of detecting the looseness of the bolt is performed.
　高周波給電部２１は、周波数掃引部２０が掃引する周波数の高周波信号を生成し、生成した高周波信号を緩み検出センサ３の給電点α，βに給電する。給電は、例えば、図示を省略しているプローブの先端を、作業者が操作して給電点α，βに接触させて行う。 The high frequency feeding unit 21 generates a high frequency signal having a frequency swept by the frequency sweeping unit 20, and feeds the generated high frequency signal to the feeding points α and β of the detection sensor 3. For example, the feeding is performed by the operator operating the tip of the probe (not shown) to bring it into contact with the feeding points α and β.
　共振周波数検出部２２は、緩み検出センサ３が取り付けられた部品１，２の共振周波数を検出する。共振周波数は、緩み検出センサ３に流れる高周波電流を高速フーリエ（ＦＦＴ）変換することで求めることができる。 The resonance frequency detection unit 22 detects the resonance frequency of the parts 1 and 2 to which the looseness detection sensor 3 is attached. The resonance frequency can be obtained by performing a fast Fourier (FFT) transform on the high frequency current flowing through the looseness detection sensor 3.
　又は、緩み検出センサ３から反射される反射波を高速フーリエ変換して共振周波数を検出するようにしてもよい。反射波から検出する場合は、共振周波数検出部２２は、給電点α，βと共振周波数記録部２３との間に直列に接続される（図示せず）。共振周波数の具体例は後述する。 Alternatively, the reflected wave reflected from the looseness detection sensor 3 may be fast Fourier transformed to detect the resonance frequency. When detecting from the reflected wave, the resonance frequency detection unit 22 is connected in series between the feeding points α and β and the resonance frequency recording unit 23 (not shown). Specific examples of the resonance frequency will be described later.
　共振周波数記録部２３は、共振周波数検出部２２で検出された共振周波数を記録する。共振周波数は、スタート周波数とストップ周波数の間の例えば反射波の周波数スペクトルのピーク値から求めることができる。または、緩み検出センサ３に流れる高周波電流の周波数スペクトルのピーク値から求めてもよい。 The resonance frequency recording unit 23 records the resonance frequency detected by the resonance frequency detection unit 22. The resonance frequency can be obtained from the peak value of the frequency spectrum of, for example, the reflected wave between the start frequency and the stop frequency. Alternatively, it may be obtained from the peak value of the frequency spectrum of the high frequency current flowing through the looseness detection sensor 3.
　判定部２４は、まず、得られたピーク値と過去に得られたピーク値とを比較し、新たな共振周波数の有無又は共振周波数の変化量に基づいてボルト４１～４４の緩みの有無を判定する。 First, the determination unit 24 compares the obtained peak value with the peak value obtained in the past, and has the presence or absence of a new resonance frequency or the presence or absence of loosening of the bolts 4 1 to 4 based on the amount of change in the resonance frequency. Is determined.
　特定部２５は、判定部２４で緩みが有ると判定された場合に、共振周波数の有無又は共振周波数の変化量に基づいて緩んだボルトを特定する。ボルトを特定する具体例については後述する。 When the determination unit 24 determines that there is looseness, the identification unit 25 identifies the loosened bolt based on the presence or absence of the resonance frequency or the amount of change in the resonance frequency. Specific examples for specifying the bolt will be described later.
　（緩んだボルトの特定方法）
　図８は、緩み検出装置１００が実行する緩んだボルトの特定方法の処理手順を示すフローチャートである。 (How to identify loose bolts)
FIG. 8 is a flowchart showing a processing procedure of a loose bolt identification method executed by the loosening detection device 100.
　本実施形態に係る緩んだボルトの特定方法は、高周波掃引ステップＳ１と、共振周波数検出ステップＳ２と、共振周波数記録ステップＳ３と、判定ステップＳ４と、特定ステップＳ５とを行う。 A method for specifying a loose bolt according to the present embodiment is a high frequency sweep step S1, a resonance frequency detection step S2, a resonance frequency recording step S3, a determination step S4, and a specific step S5.
　高周波掃引ステップＳ１は、部品１，２の結合部分に取付けられた緩み検出センサ３の給電点（α，β））に所定の範囲の周波数の高周波信号を掃引して給電する。 The high frequency sweep step S1 sweeps and feeds a high frequency signal having a frequency within a predetermined range to the feeding points (α, β) of the looseness detection sensor 3 attached to the coupling portion of the parts 1 and 2.
　共振周波数検出ステップＳ２は、緩み検出センサ３が取り付けられた部品１，２の共振周波数を検出する。 Resonance frequency detection step S2 detects the resonance frequency of the parts 1 and 2 to which the looseness detection sensor 3 is attached.
　共振周波数記録ステップＳ３は、共振周波数検出ステップＳ２で検出された共振周波数を記録する。 Resonance frequency recording step S3 records the resonance frequency detected in resonance frequency detection step S2.
　判定ステップＳ４は、共振周波数検出ステップＳ２で検出された共振周波数と過去の共振周波数（共振周波数記録ステップＳ３で記録済みの共振周波数）を比較し、新たな共振周波数の有無又は共振周波数の変化量に基づいてボルト４の緩みの有無を判定する。 In the determination step S4, the resonance frequency detected in the resonance frequency detection step S2 and the past resonance frequency (resonance frequency recorded in the resonance frequency recording step S3) are compared, and the presence or absence of a new resonance frequency or the amount of change in the resonance frequency is obtained. It is determined whether or not the bolt 4 is loose based on the above.
　特定ステップＳ５は、判定ステップＳ４でボルト４の緩みが有ると判定された場合に、新たな共振周波数の有無又は共振周波数の変化量に基づいて緩んだボルト４を特定する。 In the specific step S5, when it is determined in the determination step S4 that the bolt 4 is loose, the loose bolt 4 is specified based on the presence or absence of a new resonance frequency or the amount of change in the resonance frequency.
　以上説明したように本実施形態に係る緩んだボルトの特定方法は、二つ以上の部品を固定する複数のボルトとナットの緩みを検出する円環形状の緩み検出センサ３と緩み検出装置１００を用いて緩んだボルトを特定する緩んだボルトの特定方法であって、ボルト４が挿通される複数の孔Ｈが開けられ、ボルト４の首部４ａ、一方の部品１の表面、及び他方の部品２の表面の何れかと電気的に接続される第１導電層３ａ又は、該第１導電層３ａと同形状の非導電層を３ｂ挟んで第１導電層３ａと対向する非導電層３ｂと同形状の第２導電層３ｃの複数の孔のそれぞれの中心からの距離が異なる位置に、所定の範囲の周波数の高周波信号を掃引して給電する高周波掃引ステップＳ１と、緩み検出センサ３の共振周波数を検出する共振周波数検出ステップＳ２と、共振周波数検出ステップＳ２で検出された共振周波数を記録する共振周波数記録ステップＳ３と、共振周波数検出ステップＳ２で検出された共振周波数と過去の共振周波数を比較し、新たな共振周波数の有無又は共振周波数の変化量に基づいてボルト４の緩みの有無を判定する判定ステップＳ４と、判定ステップＳ４で緩みが有ると判定された場合に、新たな共振周波数の有無又は共振周波数の変化量に基づいて緩んだボルト４を特定する特定ステップＳ５とを行う。これにより、緩んだボルト４を特定することができる。 As described above, in the method of identifying a loose bolt according to the present embodiment, a ring-shaped looseness detection sensor 3 and a looseness detection device 100 for detecting looseness of a plurality of bolts and nuts for fixing two or more parts are used. A method of identifying a loose bolt using a method of identifying a loose bolt in which a plurality of holes H through which the bolt 4 is inserted are formed, the neck portion 4a of the bolt 4, the surface of one component 1 and the other component 2 are opened. The same shape as the first conductive layer 3a electrically connected to any of the surfaces of the above, or the non-conductive layer 3b facing the first conductive layer 3a with the non-conductive layer having the same shape as the first conductive layer 3a sandwiched 3b. The high frequency sweep step S1 for sweeping and feeding a high frequency signal having a frequency in a predetermined range and the resonance frequency of the looseness detection sensor 3 are set at positions where the distances from the centers of the plurality of holes of the second conductive layer 3c are different. The resonance frequency detection step S2 to be detected, the resonance frequency recording step S3 to record the resonance frequency detected in the resonance frequency detection step S2, and the resonance frequency detected in the resonance frequency detection step S2 and the past resonance frequency are compared. The presence or absence of a new resonance frequency or the presence or absence of a new resonance frequency when it is determined in the determination step S4 to determine the presence or absence of looseness of the bolt 4 based on the presence or absence of a new resonance frequency or the amount of change in the resonance frequency and the determination step S4. A specific step S5 for specifying the loosened bolt 4 based on the amount of change in the resonance frequency is performed. This makes it possible to identify the loose bolt 4.
　（具体例）
　図９は、本実施形態に係る緩み検出センサ３を用いて緩んだボルトを特定する具体例を示す図である。図９の横方向は周波数、縦方向は共振強度であり図５と同じである。 (Concrete example)
FIG. 9 is a diagram showing a specific example of identifying a loosened bolt using the loosening detection sensor 3 according to the present embodiment. The horizontal direction of FIG. 9 is the frequency, and the vertical direction is the resonance intensity, which is the same as that of FIG.
　具体例の緩み検出センサ３は、図１に示すようにフランジの表面に４本のボルト４で固定した。第１導電層３ａ、非導電層３ｂ、第２導電層３ｃの外半径は57.5mm、内半径は33ｍｍとし、孔Ｈの半径は7.5mm、軸４ｂの半径は7mmとした。そして、第１・第２導電層３ａ，３ｃの厚みは2mm、非導電層３ｂの厚みは0.4mmとした。 The looseness detection sensor 3 of the specific example was fixed to the surface of the flange with four bolts 4 as shown in FIG. The outer radius of the first conductive layer 3a, the non-conductive layer 3b, and the second conductive layer 3c was 57.5 mm, the inner radius was 33 mm, the radius of the hole H was 7.5 mm, and the radius of the shaft 4b was 7 mm. The thickness of the first and second conductive layers 3a and 3c was set to 2 mm, and the thickness of the non-conductive layers 3b was set to 0.4 mm.
　図９に実線で示す特性は、4本のボルト４が全て絞められた状態の共振特性を表す。緩み検出装置１００の高周波給電部２１が生成する高周波信号は、プローブを介して給電点β（図４）に相当する位置に入力した。 The characteristic shown by the solid line in FIG. 9 represents the resonance characteristic in a state where all four bolts 4 are squeezed. The high-frequency signal generated by the high-frequency feeding unit 21 of the looseness detection device 100 was input to a position corresponding to the feeding point β (FIG. 4) via the probe.
　図９に、長破線で示す特性はボルト４１が緩んだ状態、一点鎖線で示す特性はボルト４２が緩んだ状態、破線で示す特性はボルト４３が緩んだ状態、点線で示す特性はボルト４４が緩んだ状態を表す。図９に示すように共振特性の違いから緩んだボルト４１～４４の位置を特定することができる。 In FIG. 9, the characteristic shown by the long dashed line is the state where the bolt 4 1 is loosened, the characteristic shown by the alternate long and short dash line is the state where the bolt 4 2 is loosened, the characteristic shown by the broken line is the state where the bolt 4 3 is loosened, and the characteristic shown by the dotted line is. Bolt 4 Represents a loosened state. As shown in FIG. 9, the positions of the loosened bolts 4 1 to 44 can be specified from the difference in resonance characteristics.
　（給電点の変形例）
　上記の給電点α，βは、緩み検出装置１００の高周波給電部２１が生成する高周波信号が給電される第１導電層３ａ又は第２導電層３ｃの一部分である。給電点α，βは、マイクロスプリットラインで構成してもよい。 (Modification example of feeding point)
The feeding points α and β are a part of the first conductive layer 3a or the second conductive layer 3c to which the high frequency signal generated by the high frequency feeding unit 21 of the loosening detection device 100 is fed. The feeding points α and β may be configured by micro split lines.
　図１０は、給電点βをマイクロスプリットラインで構成した平面を模式的に示す図である。図１０に示すように、マイクロスプリットラインは、裏面に導体箔を形成した非導電層３ｂの表面に線状の導体箔３１を形成した構造を持つ。 FIG. 10 is a diagram schematically showing a plane in which the feeding point β is composed of microsplit lines. As shown in FIG. 10, the micro split line has a structure in which a linear conductor foil 31 is formed on the surface of a non-conductive layer 3b having a conductor foil formed on the back surface.
　マイクロスプリットラインは、特性インピーダンスの調整が容易である。したがって、緩み検出センサ３に、電磁波を効率的に入力することができる。 The micro split line makes it easy to adjust the characteristic impedance. Therefore, the electromagnetic wave can be efficiently input to the looseness detection sensor 3.
　このように、給電点α，βは、緩み検出センサ３の円環形状の外側に突出させられたマイクロスプリットラインで構成してもよい。また、マイクロスプリットラインで構成した給電点は、2箇所以上の異なる位置に配置してもよい。給電点の位置を変えることで、緩んだボルトの特定精度を向上させることができる。 As described above, the feeding points α and β may be configured by microsplit lines projecting to the outside of the ring shape of the looseness detection sensor 3. Further, the feeding points configured by the micro split line may be arranged at two or more different positions. By changing the position of the feeding point, the accuracy of identifying loose bolts can be improved.
　また、導体箔３１の先端にＳＭＡ型の同軸コネクタを配置し、緩み検出センサ３に、同軸ケーブル（図示せず）を介して高周波信号を入力してもよい。 Further, a SMA type coaxial connector may be arranged at the tip of the conductor foil 31, and a high frequency signal may be input to the looseness detection sensor 3 via a coaxial cable (not shown).
　以上説明したように、本実施形態に係る緩み検出センサ３及びそれを用いた緩んだボルトの特定方法によれば、2つの部品を固定する複数のボルトとナットの緩みを検出することができる。 As described above, according to the looseness detection sensor 3 according to the present embodiment and the method for identifying loose bolts using the same, it is possible to detect looseness of a plurality of bolts and nuts for fixing two parts.
　緩み検出センサ３を用いれば検査結果を定量的に得ることができる。また、緩み検出センサ３と緩み検出装置１００を、離して配置すれば遠隔でボルト４の緩みを検出することができる。緩み検出センサ３と緩み検出装置１００の間は、マイクロスプリットライン等の高周波信号線で接続すればよい。 If the looseness detection sensor 3 is used, the inspection result can be obtained quantitatively. Further, if the looseness detection sensor 3 and the looseness detection device 100 are arranged apart from each other, the looseness of the bolt 4 can be detected remotely. The looseness detection sensor 3 and the looseness detection device 100 may be connected by a high frequency signal line such as a micro split line.
　また、構造上の要の部分のボルト４の近傍に緩み検出装置１００を配置して、検出結果を無線で送信するようにしてもよい。そうすることで、検査に伴う危険性を排除することが出来る。また、検査コストを削減することも可能である。 Further, the loosening detection device 100 may be arranged in the vicinity of the bolt 4 at the important part of the structure so that the detection result is transmitted wirelessly. By doing so, the risks associated with the inspection can be eliminated. It is also possible to reduce inspection costs.
　なお、本発明の緩み検出センサ３は、フランジ１Ｆ，２Ｆを備えたパイプ１，２同士をボルト４とナット６で固定する例を示したがこの例に限定されない。緩み検出センサ３は、他の部品同士を固定する場合に用いることも可能である。また、ボルト４の数も上記の実施例に限定されない。このように本発明は、上記の実施形態に限定されるものではなく、その要旨の範囲内で変形が可能である。 The looseness detection sensor 3 of the present invention has shown an example in which pipes 1 and 2 provided with flanges 1F and 2F are fixed to each other with bolts 4 and nuts 6, but the present invention is not limited to this example. The looseness detection sensor 3 can also be used when fixing other parts to each other. Further, the number of bolts 4 is not limited to the above embodiment. As described above, the present invention is not limited to the above embodiment, and can be modified within the scope of the gist thereof.
１，２：部品
３：緩み検出センサ
３ａ：第１導電層
３ｂ：非導電層
３ｃ：第２導電層
４：ボルト
５：座金
６：ナット
１００：緩み検出装置
２０：周波数掃引部
２１：高周波給電部
２２：共振周波数検出部
２３：共振周波数記録部
２４：判定部
２５：特定部
２６：制御部
α，β：給電点 1, 2, Part 3: Looseness detection sensor 3a: First conductive layer 3b: Non-conductive layer 3c: Second conductive layer 4: Bolt 5: Washer 6: Nut 100: Looseness detection device 20: Frequency sweeping unit 21: High frequency power supply Unit 22: Resonance frequency detection unit 23: Resonance frequency recording unit 24: Judgment unit 25: Specific unit 26: Control unit α, β: Feed point

Claims (5)

  1. 　二つ以上の部品を固定する複数のボルトとナットの緩みを検出する円環形状のセンサであって、
    　前記ボルトが挿通される複数の孔が開けられ、前記ボルトの首部、一方の前記部品の表面、及び他方の前記部品の表面の何れかと電気的に接続される第１導電層と、
    　前記第１導電層と積層され、該第１導電層と同じ平面形状の非導電層と、
    　前記非導電層を挟んで前記第１導電層と対向して配置され、一方の前記部品の表面、他方の前記部品の表面、及び前記ナットの何れかと電気的に接続される第２導電層と
    　を備える緩み検出センサ。     An annulus-shaped sensor that detects looseness of multiple bolts and nuts that secure two or more components.
    A first conductive layer in which a plurality of holes through which the bolt is inserted are made and electrically connected to any of the neck portion of the bolt, the surface of the component on one side, and the surface of the component on the other side.
    A non-conductive layer having the same planar shape as the first conductive layer, which is laminated with the first conductive layer,
    A second conductive layer that is arranged so as to face the first conductive layer with the non-conductive layer interposed therebetween and is electrically connected to the surface of one of the components, the surface of the other component, and any of the nuts. A looseness detection sensor.
  2. 　前記第１導電層又は前記第２導電層は、高周波信号が給電される給電点を
    　備え、
    　前記給電点は、複数の前記ボルトのそれぞれの中心からの距離が異なる位置に配置される請求項１に記載の緩み検出センサ。     The first conductive layer or the second conductive layer includes a feeding point to which a high frequency signal is fed.
    The looseness detection sensor according to claim 1, wherein the feeding point is arranged at a position where the distance from the center of each of the plurality of bolts is different.
  3. 　前記給電点は、
    　前記円環形状の外側に突出させられたマイクロスプリットラインで構成される請求項２に記載の緩み検出センサ。     The feeding point is
    The looseness detection sensor according to claim 2, wherein the micro-split line is formed so as to project outward from the ring shape.
  4. 　前記給電点は、2箇所以上の異なる位置に配置される
    　請求項３に記載の緩み検出センサ。     The looseness detection sensor according to claim 3, wherein the feeding points are arranged at two or more different positions.
  5. 　二つ以上の部品を固定する複数のボルトとナットの緩みを検出する円環形状の緩み検出センサと緩み検出装置を用いて緩んだボルトを特定する緩んだボルトの特定方法であって、
    　前記ボルトが挿通される複数の孔が開けられ、前記ボルトの首部、一方の前記部品の表面、及び他方の前記部品の表面の何れかと電気的に接続される第１導電層又は、該第１導電層と同形状の非導電層を挟んで前記第１導電層と対向して配置される第２導電層の前記孔のそれぞれの中心からの距離が異なる位置に、所定の範囲の周波数の高周波信号を掃引して給電する高周波掃引ステップと、
    　前記緩み検出センサの共振周波数を検出する共振周波数検出ステップと、
    　前記共振周波数検出ステップで検出された共振周波数を記録する共振周波数記録ステップと、
    　前記共振周波数検出ステップで検出された共振周波数と過去の共振周波数を比較し、新たな共振周波数の有無又は共振周波数の変化量に基づいて前記ボルトの緩みの有無を判定する判定ステップと、
    　前記判定ステップで緩みが有ると判定された場合に、新たな共振周波数の有無又は共振周波数の変化量に基づいて緩んだボルトを特定する特定ステップと
    　を行う緩んだボルトの特定方法。     It is a method of identifying loose bolts by using an annular looseness detection sensor and a looseness detection device that detect looseness of multiple bolts and nuts that fix two or more parts.
    A first conductive layer or a first conductive layer having a plurality of holes through which the bolt is inserted and electrically connected to any of the neck of the bolt, the surface of the component on one side, and the surface of the component on the other side. High frequencies in a predetermined range at positions where the distances from the centers of the holes of the second conductive layer arranged so as to face the first conductive layer with the non-conductive layer having the same shape as the conductive layer are different from each other. A high frequency sweep step that sweeps and feeds the signal,
    A resonance frequency detection step for detecting the resonance frequency of the looseness detection sensor, and
    A resonance frequency recording step for recording the resonance frequency detected in the resonance frequency detection step, and a resonance frequency recording step.
    A determination step of comparing the resonance frequency detected in the resonance frequency detection step with the past resonance frequency and determining whether or not the bolt is loose based on the presence or absence of a new resonance frequency or the amount of change in the resonance frequency.
    A method for specifying a loose bolt by performing a specific step of specifying a loose bolt based on the presence or absence of a new resonance frequency or the amount of change in the resonance frequency when it is determined that there is looseness in the determination step.
PCT/JP2020/044010 2020-11-26 2020-11-26 Looseness detection sensor and loose bolt identification method WO2022113235A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07280762A (en) * 1994-04-11 1995-10-27 Kubota Corp Looseness detecting apparatus
JP2013210234A (en) * 2012-03-30 2013-10-10 Seiko Epson Corp Tightening/relaxing detection sensor and tightening/relaxing detection system
WO2020090446A1 (en) * 2018-10-29 2020-05-07 日本電信電話株式会社 Loosening detection structure and loosening detection method using said structure

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07280762A (en) * 1994-04-11 1995-10-27 Kubota Corp Looseness detecting apparatus
JP2013210234A (en) * 2012-03-30 2013-10-10 Seiko Epson Corp Tightening/relaxing detection sensor and tightening/relaxing detection system
WO2020090446A1 (en) * 2018-10-29 2020-05-07 日本電信電話株式会社 Loosening detection structure and loosening detection method using said structure

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