JP2021105589A - Looseness detection device for rotating fastener - Google Patents

Abstract

To reduce cost and facilitate execution in a device that detects looseness of a rotating fastener when the rotating fasteners have different size.SOLUTION: A looseness detection device comprises: a mediation member having an engagement part that includes an insertion hole through which an axis of a rotating fastener passes and is engaged with the rotating fastener in a relatively unrotatable manner, and a part to be pasted that projects from the engagement part in a radial direction orthogonal to the axis of the insertion hole; and an RFID sensor having a base sheet that is pasted to the part to be pasted and a seating face of a structure so as to cross a boundary between the part to be pasted of the mediation member and the seating face, an electric circuit that is formed on the base sheet and cross the boundary, and an RFID chip that is electrically connected with the electric circuit.SELECTED DRAWING: Figure 2

Description

The present invention relates to a device that detects looseness of a rotary fastener that rotates around an axis and transmits an axial force to a seating surface of a structure.

Patent Document 1 discloses a looseness detection sensor that is attached to the seat surface and the bolt head so as to straddle the boundary between the seat surface of the structure and the bolt head to detect looseness of the bolt. .. The looseness detection sensor has an RFID chip and an electric circuit mounted on the base sheet. According to this, when the bolt is loosened, the electric circuit is broken as the base sheet of the loosening detection sensor is broken, and the looseness of the bolt can be detected.

JP-A-2019-78611

However, if the bolt size is different, the relationship between the rotation angle of the bolt and the amount of rotational displacement of the outer peripheral surface of the bolt head is also different. That is, even if the rotation angle of the bolt is constant, if the bolt size is large, the amount of rotational displacement of the outer peripheral surface of the bolt head is large, and if the bolt size is small, the amount of rotational displacement of the outer peripheral surface of the bolt head is small. .. Therefore, when the bolt size is large, the electric circuit of the loosening detection sensor is broken even if the rotation angle of the bolt loosening is small, while when the bolt size is small, the loosening detection is detected when the rotation angle of the bolt loosening is small. The electric circuit of the sensor does not break.

If looseness detection sensors having different breaking strengths are prepared for each bolt size, the electric circuit can be broken at a constant rotation angle even if the bolt sizes are different. However, as the types of looseness detection sensors increase, there is a problem that the cost of the looseness detection sensor increases. In addition, it is necessary to use a looseness detection sensor of a type suitable for the bolt size without mistake, which causes a problem that construction management becomes complicated. When a combination of bolts and nuts is used instead of a single bolt, the looseness detection sensor may be attached to the nut instead of being attached to the bolt head.

Therefore, an object of the present invention is to reduce the cost and facilitate the construction when the rotary fasteners have different sizes in the device for detecting the looseness of the rotary fasteners.

The looseness detection device for a rotary fastener according to one aspect of the present invention is a device for detecting looseness of a rotary fastener that rotates around an axis and transmits an axial force to a seating surface of a structure, through which the axis passes. An intermediary member having an engaging portion that includes an insertion hole and engages with the rotary fastener so as to be relatively non-rotatable, and an attached portion that protrudes from the engaging portion in a radial direction orthogonal to the axis of the insertion hole. And the base sheet to be attached to the attached portion and the seat surface so as to straddle the boundary between the attached portion of the intermediary member and the seat surface of the structure, and the base sheet formed on the base sheet. An RFID sensor comprising an electrical circuit that traverses the boundary and an RFID chip that is electrically connected to the electrical circuit.

According to the above configuration, the engaging portion in the mediating member is made constant by keeping the distance from the axis of the insertion hole to the attachment portion while changing the size of the engaging portion of the mediating member according to the size of the rotary fastener. The relationship between the angle of rotation (that is, the angle of rotation of the rotary fastener) and the amount of rotational displacement of the portion to be attached can be made constant.

According to the present invention, even when the sizes of the rotary fasteners are different, the RFID sensor can be shared, and the cost can be reduced and the construction can be facilitated.

FIG. 1 is a schematic diagram of a bolt loosening detection system. FIG. 2 is a perspective view of the looseness detection device according to the first embodiment. FIG. 3 is a plan view of the mediator member shown in FIG. FIG. 4A is a cross-sectional view of an intermediary member of a first modification of the looseness detection device of the first embodiment. FIG. 4B is a cross-sectional view of an intermediary member of a second modification of the looseness detection device of the first embodiment. FIG. 5 is a perspective view of the looseness detection device according to the second embodiment. FIG. 6 is a vertical cross-sectional view of the looseness detection device according to the third embodiment. FIG. 7 is a vertical cross-sectional view of the looseness detection device according to the fourth embodiment. FIG. 8 is a plan view of the mediator member shown in FIG. 7. FIG. 9 is a vertical cross-sectional view of an intermediary member of a modified example of the looseness detection device of the fourth embodiment.

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

FIG. 1 is a schematic view of a bolt B loosening detection system 1. The looseness detection system 1 can be applied to all of the first to fifth embodiments described later. As shown in FIG. 1, the looseness detection system 1 automatically detects looseness of a bolt B (rotary fastener) provided on a structure 10 by using an RFID (Radio frequency identifier), and maintains the bolt B. It is for reducing. The structure 10 includes transportation equipment such as railroad vehicles, aircraft, and ships, and stationary structures such as bridges. The looseness detection target is not limited to the bolt B, and any other rotary fastener (for example, a nut) that rotates around the axis and transmits the axial force to the seat surface 10a of the structure 10 may be used.

The looseness detection system 1 of the bolt B includes a plurality of looseness detection devices 11, an RFID reader 2, a data processing device 3, a server 4, and a database 5. The plurality of looseness detection devices 11 are attached to the plurality of bolts B, respectively.

The RFID reader 2 reads the signal including the ID information and the detection information of the RFID chip 43, which will be described later, of the looseness detection device 11 in a non-contact manner. The RFID reader 2 may be installed in the vicinity of the structure 10 or may be a portable type possessed by an operator. The data processing device 3 processes the signal read by the RFID reader 2 and transmits it to the server 4 via the network N (for example, the Internet, LAN or WAN, satellite communication line, mobile phone network, etc.).

In the database 5, the correspondence relationship between the ID information of the RFID chip 43, which will be described later, and the location information indicating the location where the RFID chip 43 is installed (for example, the model number and the part of the structure 10) is stored in advance. The server 4 calculates and processes the signal received from the data processing device 3 while referring to the database 5, and transmits the location of the bolt B where the looseness has occurred to the maintenance management center. The processing data of the server 4 is stored and stored in the database 5.

(First Embodiment)
FIG. 2 is a perspective view of the looseness detection device 11 according to the first embodiment. FIG. 3 is a plan view of the mediator member 21 shown in FIG. As shown in FIGS. 2 and 3, the looseness detection device 11 includes an intermediary member 21 and an RFID sensor 22. The bolts B provided on the structure 10 are a shaft portion Bb (hereinafter referred to as a bolt shaft portion) having a male screw formed on the outer peripheral surface and a non-circular shape (for example, a hexagon) provided at one end of the shaft portion Bb. It is provided with a head Ba (hereinafter, referred to as a bolt head) having an outer peripheral surface of (polygon such as).

By rotating the bolt B around its axis X, the bolt head portion Ba transmits the axial force to the seat surface 10a of the structure 10. The looseness detection device 11 detects looseness in which the axial force decreases as the bolt head Ba rotates relative to the seat surface 10a of the structure 10 beyond a predetermined angle. The seating surface 10a of the structure 10 is made of metal.

The intermediary member 21 includes an engaging portion 31 and a sticking portion 32. The engaging portion 31 includes a washer portion 31a and a pair of claw portions 31b. The washer portion 31a has an insertion hole H1 through which the axis X of the bolt B passes. The insertion hole H1 has a circular shape having a diameter larger than that of the bolt shaft portion Bb, but the shape is not limited to a circular shape. The washer portion 31a is sandwiched between the bolt head Ba and the seat surface 10a. That is, the washer portion 31a serves as a washer in a state where the bolt shaft portion Bb is inserted into the insertion hole H1.

The pair of claw portions 31b project from the washer portion 31a in the normal direction of the washer portion 31a and face each other. The protruding dimension of the claw portion 31b is smaller than the dimension of the bolt head Ba in the axis X direction. This makes it possible to rotate the bolt head Ba with a tool without interfering with the claw portion 31b. In a state where the bolt shaft portion Bb is inserted into the insertion hole H1, the pair of claw portions 31b are arranged at positions facing each other in the radial direction of the bolt head portion Ba, and sandwich the outer peripheral surface of the bolt head portion Ba. That is, when the claw portion 31b comes into contact with the polygonal outer peripheral surface of the bolt head Ba, the engaging portion 31 engages with the bolt head Ba in a relative non-rotatable manner.

The claw portion 31b may be formed in advance in a shape that abuts on the side surface of the bolt head Ba, or may abut on the side surface of the bolt head Ba by crimping the claw portion 31b toward the bolt head Ba. It may be configured to allow. Further, the number of claw portions 31b is not limited to a pair, and may be one or three or more. The claw portion 31b is not limited to a shape along only one side of the polygon of the bolt head Ba, and may have a bent shape along a plurality of sides of the polygon of the bolt head Ba.

The attached portion 32 protrudes from the engaging portion 31 in the radial direction orthogonal to the axis (corresponding to the axis X of the bolt B) of the insertion hole H1 of the engaging portion 31. Specifically, the attached portion 32 projects like a tongue in one direction in the radial direction from the washer portion 31a of the engaging portion 31. The attachment portion 32 includes a metal substrate portion 51 and an insulating spacer portion 52. The metal substrate portion 51 is continuous with the engaging portion 31. The engaging portion 31 and the metal substrate portion 51 are made of metal (for example, iron). For example, the engaging portion 31 and the metal substrate portion 51 are formed by pressing a metal plate.

The insulating spacer portion 52 is laminated on the surface of the metal substrate portion 51 opposite to the seat surface 10a. The insulating spacer portion 52 is made of an insulating material (for example, non-conductive synthetic resin or rubber). The insulating spacer portion 52 is preliminarily integrated with the metal substrate portion 51. For example, the insulating spacer portion 52 may be pre-bonded to the metal substrate portion 51 with an adhesive, or may be vulcanized and bonded in advance.

The RFID sensor 22 includes a base sheet 41, a detection circuit 42 (electric circuit), an RFID chip 43, an antenna circuit 44, and a top sheet 45. An adhesive is provided on the back surface of the base sheet 41 facing the seat surface 10a. The base sheet 41 is made of an insulating material (for example, a non-conductive synthetic resin). The base sheet 41 is attached to the insulating spacer portion 52 and the seat surface 10a so as to straddle the boundary Y between the attachment portion 32 of the intermediary member 21 and the seat surface 10a of the structure 10. The boundary Y is a boundary between the attached portion 32 and the seat surface 10a in the circumferential direction around the axis X.

The base sheet 41 is formed with a planned fracture portion 41a at a position corresponding to the boundary Y. The planned fracture portion 41a is a linear portion that is more fragile than the other portions of the base sheet 41. In the present embodiment, the planned break portion 41a is a perforation. The planned fracture portion 41a is not limited to the perforation as long as it forms a portion of the base sheet 41 that is preferentially fractured, and may be, for example, a thin-walled portion or a cut portion. Further, the base sheet 41 may not be provided with the planned fracture portion 41a.

The detection circuit 42 is provided on the surface of the base sheet 41 (on the side opposite to the seat surface 10a). The detection circuit 42 forms a closed circuit together with the RFID chip 43. That is, both ends of the detection circuit 42 are electrically connected to the RFID chip 43. The detection circuit 42 crosses the planned fracture portion 41a. That is, the detection circuit 42 crosses the boundary Y between the attached portion 32 of the intermediary member 21 and the seat surface 10a of the structure 10.

The RFID chip 43 is electrically connected to the detection circuit 42. The RFID chip 43 is a passive RDID tag chip that does not require a power source. The RFID chip 43 is configured so that its own detection information is rewritten when the detection circuit 42 is disconnected. That is, the RFID chip 43 stores its own ID information and detection information indicating whether or not the detection circuit 42 connected to itself is disconnected.

For example, the RFID chip 43 stores "0" as detection information when the detection circuit 42 is disconnected, and stores "1" as detection information when the detection circuit 42 is not disconnected. The RFID chip 43 is arranged so as to correspond to the attachment portion 32. That is, the insulating spacer portion 52 is arranged between the RFID chip 43 and the metal substrate portion 51.

The antenna circuit 44 is electrically connected to the RFID chip 43. The RFID chip 43 generates electricity based on the signal received via the antenna circuit 44, and wirelessly transmits the ID information and the detection information to the outside via the antenna circuit 44. The antenna circuit 44 is arranged so as to correspond to the attachment portion 32. That is, the insulating spacer portion 52 is arranged between the antenna circuit 44 and the metal substrate portion 51.

The top sheet 45 is laminated on the base sheet 41 so as to cover the detection circuit 42, the RFID chip 43, and the antenna circuit 44. Like the base sheet 41, the top sheet 45 may be provided with a planned break portion corresponding to the boundary Y, or the top sheet 45 may not be provided with the planned break portion. The RFID sensor 22 may not have the top sheet 45.

When the bolt B loosens beyond a predetermined angle, a relative displacement occurs between the portion of the RFID sensor 22 attached to the bolt head Ba and the portion of the RFID sensor 22 attached to the seat surface 10a. .. Then, the RFID sensor 22 is distorted, the base sheet 41 is broken at the planned break portion 41a, and the detection circuit 42 is broken. When the detection circuit 42 is disconnected, the detection information of the RFID chip 43 is rewritten from "1" to "0". In this state, the reader 2 (see FIG. 1) wirelessly reads the information of the RFID chip 43 via the antenna circuit 44 to detect whether or not the bolt B has loosened beyond a predetermined angle. can.

The size of the engaging portion 31 of the intermediary member 21 is changed according to the size of the bolt B. That is, the type of the intermediary member 21 is prepared according to the type of the bolt B. However, in any type of intermediary member 21, the distance L from the axis X of the insertion hole H1 to the center of the attachment portion 32 is kept constant. By keeping the distance L constant while changing the size of the engaging portion 31 of the intermediary member 21 according to the size of the bolt B, the rotation angle of the engaging portion 31 in the intermediary member 21 (that is, the rotation angle of the bolt B). The relationship between the affixed portion 32 and the rotational displacement amount of the affixed portion 32 can be made constant. Therefore, even when the size of the bolt B is different, the RFID sensor 22 can be shared, and the cost can be reduced and the construction can be facilitated.

Further, since the attached portion 32 protrudes in a radial direction from the engaging portion 31 in a tongue shape, the mediating member 21 is restricted even when the seating surface 10a in the vicinity of the bolt B in the structure 10 is restricted. Can be installed. Further, since the claw portion 31b protruding from the washer portion 31a is brought into contact with the side surface of the bolt head portion Ba, the engaging portion 31 can be made relatively non-rotatable with respect to the bolt head portion Ba with a simple configuration.

Further, since the pair of claw portions 31b sandwich the bolt head portion Ba, the intermediary member 21 can be stably rotated together with the bolt head portion Ba. Further, the pair of claw portions 31b can be easily crimped toward the side surface of the bolt head portion Ba. Further, since the mediator member 21 also serves as a washer, it is possible to suppress an increase in the number of parts and work man-hours. Further, since the insulating spacer portion 52 is provided on the attached portion 32 and the insulating spacer portion 52 is interposed between the RFID chip 43 and the metal substrate portion 51, the RFID chip 43 is electromagnetically transmitted from the metal substrate portion 51 of the intermediary member 21. It is possible to prevent adverse effects.

Further, the boundary Y between the attached portion 32 of the intermediary member 21 and the seating surface 10a of the structure 10 is the boundary between the attached portion 32 and the seating surface 10a in the circumferential direction around the axis X. The base sheet 41 of the RFID sensor 22 is arranged along the circumferential direction around the axis X, so that the detection circuit 42 can be easily disconnected when the bolt B is loosened.

The claw portion 31b is projected from the washer portion 31a on the same plane as the washer portion 31a to form a flat plate, and the claw portion 31b is attached to the washer portion 31a when the intermediary member 21 is attached to the bolt B. It may be bent at a right angle. The intermediary member 21 may be made of an insulating material, in which case the insulating spacer 52 can be omitted.

FIG. 4A is a cross-sectional view of the mediator member 121 of the first modification of the looseness detection device 11 of the first embodiment. As shown in FIG. 4A, the attached portion 132 of the intermediary member 121 may have a slope surface 132a inclined toward the seat surface 10a. The slope surface 132a is tilted on the side end surface on the boundary Y side of the attachment portion 132 so that the angle formed by the back surface of the attachment portion 132 (the surface adhered to the seat surface 10a) and the slope surface 132a is an acute angle. It is a thing.

That is, the metal substrate portion 151 of the attachment portion 132 and the side end faces of the insulating spacer portion 152 are formed in a tapered shape continuous with each other. As a result, the angle formed by the portion of the seat surface 10a adjacent to the side of the attachment portion 132 and the slope surface 132a becomes an obtuse angle. Therefore, by using the slope surface 132a, the RFID sensor 22 can be smoothly attached to the affixed portion 132 and the seat surface 10a, and the RFID sensor 22 can be prevented from rising.

FIG. 4B is a cross-sectional view of the mediator member 221 of the second modification of the looseness detection device 11 of the first embodiment. As shown in FIG. 4B, the entire surface (the surface opposite to the back surface) of the attachment portion 232 of the intermediary member 221 may be a slope surface 232a inclined toward the seat surface 10a. Specifically, at least the front surface of the insulating spacer portion 252 of the attached portion 232 forms an acute angle with the back surface of the attached portion 132 (the surface adhered to the seat surface 10a).

In the example of FIG. 4B, both the metal substrate portion 251 and the insulating spacer portion 252 have a wedge shape in which the wall thickness gradually decreases toward the boundary Y. Also by this, by using the slope surface 232a, the RFID sensor 22 can be smoothly attached to the attachment portion 232 and the seat surface 10a, and the RFID sensor 22 can be prevented from rising. The first and second modifications are not limited to the application to the first embodiment, and may be applied to the second to fourth embodiments described later.

(Second Embodiment)
FIG. 5 is a perspective view of the looseness detection device 311 according to the second embodiment. The same reference numerals are given to the configurations common to those of the first embodiment, and the description thereof will be omitted. As shown in FIG. 5, the looseness detection device 311 includes an intermediary member 321 and an RFID sensor 322. The intermediary member 321 includes an engaging portion 31 and an attached portion 332. The attached portion 332 has a metal substrate portion 51, but does not include the insulating spacer portion 52 of the first embodiment. The RFID sensor 322 has the intermediary member 321 and the intermediary member 321 straddling the boundary Y between the attached portion 332 of the intermediary member 321 and the seat surface 10a of the structure 10 in a state changed by 180 ° from the first embodiment. It is attached to the seat surface 10a.

The RFID sensor 322 includes a base sheet 41, a detection circuit 42, an RFID chip 43, an antenna circuit 44, and a top sheet 45, and further includes an insulating spacer 346 made of an insulating material. The insulating spacer 346 is preliminarily fixed to the back surface (the surface on the seat surface 10a side) of the area of the base sheet 41 in which the RFID chip 43 and the antenna circuit 44 are arranged. For example, the insulating spacer 346 is pre-bonded to the back surface of the base sheet 41 with an adhesive. An adhesive is provided on the back surface of the insulating spacer 346 (the surface facing the seat surface 10a). The insulating spacer 346 is attached to the seat surface 10a of the structure 10.

The RFID chip 43 and the antenna circuit 44 are arranged corresponding to the insulating spacer 346. That is, the insulating spacer 346 is arranged between the set of the RFID chip 43 and the antenna circuit 44 and the seat surface 10a. The detection circuit 42 is arranged so as to cross the boundary Y between the attachment portion 332 and the seat surface 10a. With such a configuration, it is possible to prevent the RFID chip 43 and the antenna circuit 44 from being electromagnetically adversely affected by the metal seating surface 10a of the structure 10. Since the other configurations are the same as those of the first embodiment described above, the description thereof will be omitted.

(Third Embodiment)
FIG. 6 is a vertical cross-sectional view of the looseness detection device 411 according to the third embodiment. The same reference numerals are given to the configurations common to those of the first embodiment, and the description thereof will be omitted. As shown in FIG. 6, a spring washer W1 (belleville spring) is sandwiched between the bolt head Ba and the seat surface 10a. The looseness detection device 411 includes an intermediary member 421 and an RFID sensor 22. The intermediary member 421 is further provided with a stepped portion 433 in addition to the engaging portion 31 and the attached portion 32. The washer portion 31a of the engaging portion 31 is sandwiched between the bolt head Ba and the spring washer W1.

The step portion 433 is formed between the washer portion 31a and the affixed portion 32 so that the affixed portion 32 approaches the seat surface 10a with respect to the washer portion 31a. The distance in the axis X direction between the back surface of the washer portion 31a and the back surface of the attached portion 32 is substantially the same as the wall thickness of the spring washer W1. According to this configuration, even when the spring washer W1 is inserted between the washer portion 31a and the seat surface 10a, the affixed portion 32 is landed on the seat surface 10a and smoothly on the affixed portion 32 and the seat surface 10a. The RFID sensor 22 can be attached to the. Since the other configurations are the same as those of the first embodiment described above, the description thereof will be omitted.

(Fourth Embodiment)
FIG. 7 is a vertical cross-sectional view of the looseness detection device 511 according to the fourth embodiment. FIG. 8 is a plan view of the mediator member 521 shown in FIG. 7. The same reference numerals are given to the configurations common to those of the first embodiment, and the description thereof will be omitted. As shown in FIG. 7, a washer W2 made of metal is sandwiched between the bolt head Ba and the seat surface 10a. As shown in FIGS. 7 and 8, the looseness detection device 511 includes an intermediary member 521 and an RFID sensor 22. The mediator member 521 is integrally molded with an insulating material (for example, synthetic resin). The intermediary member 521 includes an engaging portion 531, a sticking portion 532, and a step portion 533.

The engaging portion 531 has a flat plate shape. The engaging portion 531 has a non-circular insertion hole H2. Specifically, the insertion hole H2 has a polygonal shape (for example, a hexagonal shape) substantially the same as the outer peripheral surface of the bolt head Ba, and functions as an engagement hole. That is, the insertion hole H2 of the engaging portion 531 is fitted to the outer peripheral surface of the bolt head Ba, so that the engaging portion 531 engages with the bolt head Ba in a relative non-rotatable manner.

The attached portion 532 has a flat plate shape. The RFID sensor 22 is attached to the attached portion 532 and the seat surface 10a so as to straddle the boundary between the attached portion 532 and the seat surface 10a. Since the sticking portion 532 is made of an insulating material, the RFID chip 43 and the antenna circuit 44 (see FIG. 2) of the RFID sensor 22 can be arranged corresponding to the sticking portion 532. That is, it is not necessary to additionally provide an insulating spacer between the set of the RFID chip 43 and the antenna circuit 44 of the RFID sensor 22 and the attached portion 532.

The step portion 533 is formed between the engaging portion 531 and the attached portion 532 so that the attached portion 532 approaches the seat surface 10a with respect to the engaging portion 531. The distance in the axis X direction between the back surface of the engaging portion 531 and the back surface of the attached portion 532 is substantially the same as the wall thickness of the washer W2. The mediator member 521 does not have to include the step portion 533. For example, the sticking portion 532 may be thickened so that the surface of the engaging portion 531 and the surface of the sticking portion 532 are flush with each other.

According to this configuration, it is possible to easily realize a configuration in which the intermediary member 521 rotates stably with the bolt B. Further, since the mediator member 521 is made of an insulating material, the mediator member 521 interposed between the RFID sensor 22 and the seat surface 10a prevents the RFID sensor 22 from being electromagnetically adversely affected by the metal seat surface 10a. can. Since the other configurations are the same as those of the first embodiment described above, the description thereof will be omitted.

FIG. 9 is a vertical cross-sectional view of the mediator member 621 of the modified example of the looseness detection device 511 of the fourth embodiment. As shown in FIG. 9, the intermediary member 621 includes an engaging portion 631, a sticking portion 532, and a step portion 533. The structure of the attached portion 532 and the stepped portion 533 in the intermediary member 621 is the same as that of FIG. 7. The engaging portion 631 includes a flat plate portion 631a and a protruding portion 631b. The flat plate portion 631a is the same as the engaging portion 531 in FIG. That is, the flat plate portion 631a has a polygonal insertion hole H2.

The protrusion 631b protrudes in the axis X direction from the peripheral edge of the insertion hole H2. In other words, the peripheral edge of the insertion hole H2 in the flat plate portion 631a is thickened. As a result, the dimension of the peripheral edge of the insertion hole H2 in the axis X direction increases, and the contact area of the engaging portion 631 with the outer peripheral surface of the bolt head Ba increases. According to this configuration, it is possible to easily realize a configuration in which the intermediary member 621 rotates stably with the bolt B.

The present invention is not limited to the above-described embodiment, and its configuration can be changed, added, or deleted. For example, some configurations in one embodiment can be arbitrarily extracted separately from other configurations in that embodiment, and some configurations in one embodiment can be applied to other embodiments. You may. Further, the electric circuit that breaks when the bolt is loosened may be an antenna circuit instead of the detection circuit. That is, when the RFID reader cannot communicate with the RFID chip, it may be determined that the bolt loosening that breaks the antenna circuit has occurred.

10 Structure 10a Seat surface 11,311,411,511 Bolt loosening detection device 21,321,421,521,621 Mediating member 22,322 RFID sensor 31,531,631 Engagement part 31a Washer part 31b Claw part 32, 132,232,332,532 Attached part 132a, 232a Slope surface 41 Base sheet 42 Detection circuit 43 RFID chip 44 Antenna circuit 51,151,251 Metal substrate part 52,152,252 Insulation spacer part 346 Insulation spacer 433,533 Step Part H1, H2 Insertion hole B Bolt (rotary fastener)
X-axis Y boundary

Claims (12)

A device that detects looseness of rotary fasteners that rotate around an axis and transmit axial force to the seating surface of a structure.
An engaging portion that includes an insertion hole through which the axis passes and engages the rotary fastener in a relative non-rotatable manner, and an attached portion that protrudes from the engaging portion in a radial direction orthogonal to the axis of the insertion hole. With an intermediary member that has
The attached portion and the base sheet attached to the seat surface so as to straddle the boundary between the attached portion of the intermediary member and the seat surface of the structure, and the base sheet formed on the base sheet. A device for detecting looseness of a rotary fastener, comprising an RFID sensor having an electric circuit that crosses a boundary and an RFID chip that is electrically connected to the electric circuit. The looseness detecting device for a rotary fastener according to claim 1, wherein the attached portion projects from the engaging portion in a tongue shape in one direction in the radial direction. At least the engaging part is made of metal
The engaging portion includes the insertion hole and is sandwiched between the rotary fastener and the seat surface so as to project from the washer portion and abut against the non-circular outer peripheral surface of the rotary fastener. Consists of at least one claw and
The looseness detecting device for a rotary fastener according to claim 1 or 2, wherein the attached portion projects from the washer portion in the radial direction. The looseness detection device for a rotary fastener according to claim 3, wherein the at least one claw portion includes a pair of claw portions arranged at positions facing each other in the radial direction for sandwiching the rotary fastener. The intermediary member according to claim 3 or 4, wherein the intermediary member has a step portion formed between the washer portion and the affixed portion so that the affixed portion approaches the seat surface with respect to the washer portion. Looseness detection device for rotary fasteners. The looseness detection device for a rotary fastener according to claim 1 or 2, wherein the insertion hole of the engaging portion has a non-circular shape fitted to a non-circular outer peripheral surface of the rotary fastener. The intermediary member according to claim 6, wherein the intermediary member has a stepped portion formed between the engaging portion and the attached portion so that the attached portion approaches the seat surface with respect to the engaging portion. Looseness detection device for rotary fasteners. The looseness detection device for a rotary fastener according to claim 6 or 7, wherein the mediator member is made of an insulating material. The attached portion includes a metal substrate portion and an insulating spacer portion provided on a surface of the metal substrate portion opposite to the seating surface.
The RFID chip is arranged so as to correspond to the attached portion.
The looseness detection device for a rotary fastener according to any one of claims 1 to 7, wherein the insulating spacer portion is arranged between the RFID chip and the metal substrate portion. The loosening of the rotary fastener according to any one of claims 1 to 8, wherein the RFID sensor further has an insulating spacer provided on the base sheet and arranged between the RFID chip and the seat surface. Detection device. The looseness detection device for a rotary fastener according to any one of claims 1 to 10, wherein the attached portion has a slope surface inclined toward the seat surface. The looseness detection device for a rotary fastener according to any one of claims 1 to 11, wherein the boundary is a boundary between the attached portion and the seat surface in the circumferential direction around the axis.

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