Detection device

Abstract

Provided is a detection device in which the rotation of a deformable body is suppressed.　This detection device includes: a deformable body including a body section that has a first end and a second end, and a through-hole that penetrates the body section in a direction connecting a first side, where the first end is provided, and a second side, where the second end is provided, the through-hole having a bolt part of a fastening mechanism inserted thereinto; a strain sensor that detects strain of the deformable body caused by a fastening axial force applied in an extending direction of the through-hole by the fastening mechanism; and a case that accommodates at least a portion of the body section of the deformable body along a first outside surface of the body section. The deformable body includes a protrusion that protrudes outward from the first outside surface of the body section in a planar view. The case includes an opposing wall portion that opposes the first outside surface. The opposing wall portion includes a recess that is recessed outward in a planar view and that accommodates the protrusion.

Description

[Technical field]

[0001] The present disclosure relates to a detection device. [Background technology]

[0002] Conventionally, there has been a load cell comprising: a cylindrical first member having a first flange and a first screw thread on the inside; a cylindrical second member arranged concentrically with the first member and having a second flange and a second screw thread on the outside; a cylindrical first structure having a third screw thread on the outside that is screwed onto the first screw thread; a cylindrical second structure provided inside the first structure and having a fourth screw thread on the inside that is screwed onto the second screw thread; and a third structure provided between the first structure and the second structure and having elasticity; a first strain generating body with the first member attached to the outside of the first structure and the second member attached to the inside of the second structure; and at least one second strain generating body having a first end provided between the first structure and the first flange and a second end provided between the second structure and the second flange, and having a strain sensor (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-148494 A Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional load cells, the first member is attached to the outside of the first structure of the first flexure body by screwing the first screw thread and the third screw thread together, but if the screw screwed between the first member and the first structure of the first flexure body loosens, the first flexure body may rotate relative to the first member. If the first flexure body rotates, problems such as disconnection of the wiring of the strain sensor or a decrease in detection accuracy due to rattling relative to the first member may occur.

[0005] Therefore, an object of the present invention is to provide a detection device in which the rotation of the strain body is suppressed. [Means for solving the problem]

[0006] A detection device according to an embodiment of the present disclosure includes a strain generating body having a main body having a first end and a second end, and a through hole penetrating the main body in a direction connecting a first side on which the first end is located and a second side on which the second end is located, with a bolt portion of a fastening mechanism being inserted into the through hole, a strain sensor that detects distortion of the strain generating body due to a fastening axial force applied by the fastening mechanism in the extension direction of the through hole, and a case that houses at least a portion of the main body portion of the strain generating body along a first outer surface of the main body portion, wherein the strain generating body has a convex portion that protrudes outward beyond the first outer surface of the main body portion in a planar view, and the case has an opposing wall portion that faces the first outer surface, and the opposing wall portion has a recess that is recessed outward in a planar view and houses the convex portion. Effect of the Invention

[0007] It is possible to provide a detection device in which the rotation of the strain body is suppressed. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view showing a detection device 100 according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing a state in which the detection device 100 is disassembled. [Diagram 3] FIG. 2 is a cross-sectional view taken along the line AA in FIG. [Figure 4] FIG. 2 is a cross-sectional view taken along the line BB in FIG. [Diagram 5] 2 is a diagram showing a strain element 120 and a strain sensor 130. FIG. [Figure 6] 2 is a diagram showing a strain element 120 and a strain sensor 130. FIG. [Figure 7] 1 is a diagram showing a state in which upper case 110U is removed from detection device 100 and sealing resin 150 is omitted. [Figure 8]1 is a diagram showing a state in which a strain element 120 and a strain sensor 130 are arranged in a lower case 110L. [Figure 9] 1 is a diagram showing a state in which a strain element 120 and a strain sensor 130 are arranged in a lower case 110L. [Figure 10] FIG. 2 is a diagram showing an example of a state in which the detection device 100 is used. [Figure 11A] FIG. 2 is a diagram showing a detection device 100A according to a first modified example of the first embodiment. [Figure 11B] FIG. 2 is a diagram showing a state in which the detection device 100A is disassembled. [Figure 12A] FIG. 13 is a diagram showing a detection device 100B of a first modified example of the first embodiment. [Figure 12B] FIG. 2 is a diagram showing a state in which the detection device 100B is disassembled. [Figure 13A] FIG. 13 is a diagram showing a flexure body 120C of a third modified example. [Figure 13B] FIG. 13 is a diagram showing a flexure body 120C of a third modified example. [Figure 14A] FIG. 13 is a diagram showing a flexure body 120D of a fourth modified example. [Figure 14B] FIG. 13 is a diagram showing a flexure body 120D of a fourth modified example. [Figure 15A] FIG. 13 is a diagram showing a flexure body 120E of a fifth modified example. [Figure 15B] FIG. 13 is a diagram showing a flexure body 120E of a fifth modified example. [Figure 16] FIG. 11 is a perspective view showing a detection device 200 according to a second embodiment. [Figure 17] FIG. 11 is a perspective view showing a detection device 200 according to a second embodiment. [Figure 18] FIG. 2 is a diagram showing a state in which the detection device 200 is disassembled. [Figure 19] FIG. 2 is a diagram showing a state in which the detection device 200 is disassembled. [Figure 20] 17 is a cross-sectional view taken along the line CC in FIG. 16. [Figure 21] 17 is a cross-sectional view taken along the line CC in FIG. 16. [Figure 22] FIG. 17 is a cross-sectional view taken along the line DD in FIG. 16. [Diagram 23]1 is a diagram showing a state in which upper case 110U is removed from detection device 200 and sealing resin 150 is omitted. [Figure 24] FIG. 24 is an enlarged view of a portion of FIG. 23. [Diagram 25] 13 is a diagram showing the results of a simulation in which a strain distribution is calculated when a fastening axial force is applied to a strain element 220. FIG. [Figure 26] 13 is a diagram showing a strain generating body 320 of the third embodiment. FIG. [Figure 27] 13 is a diagram showing the results of a simulation in which the distribution of strain when a fastening axial force is applied to a strain generating body 320 is calculated. FIG. [Figure 28A] 13 is a diagram showing a strain body 420 of the fourth embodiment. FIG. [Figure 28B] 13 is a diagram showing a strain body 420 of the fourth embodiment. FIG. [Figure 29A] FIG. 13 is a diagram showing a strain body 420 of a modified example of the fourth embodiment. [Figure 29B] FIG. 13 is a diagram showing a strain body 420 of a modified example of the fourth embodiment. [Figure 30A] FIG. 11 is a perspective view showing a detection device 500 according to a fifth embodiment. [Figure 30B] FIG. 11 is a perspective view showing a detection device 500 according to a fifth embodiment. [Figure 31A] FIG. 2 is a diagram showing a state in which the detection device 500 is disassembled. [Figure 31B] FIG. 13 is a diagram showing a strain generating body 520 to which an O-ring 560 is attached. [Figure 32A] 13 is a diagram showing a lower case 510L of the case 510 and a flexure body 520. FIG. [Figure 32B] 13 is a diagram showing a lower case 510L of the case 510 and a flexure body 520. FIG. [Figure 33A] FIG. 30C is a cross-sectional view taken along the line EE of FIGS. 30A and 30B. [Figure 33B] FIG. 30C is a cross-sectional view taken along the line EE of FIGS. 30A and 30B. [Diagram 34] FIG. 13 is a diagram showing a detection device 500M1 of a first modified example of the fifth embodiment. [Figure 35A] 13 is a diagram showing a flexure body 520M2 of a second modified example of the fifth embodiment. FIG. [Figure 35B] 13 is a diagram showing a flexure body 520M2 of a second modified example of the fifth embodiment. FIG. [Figure 36A] 13 is a diagram showing a flexure body 520M3 of a third modified example of the fifth embodiment. FIG. [Figure 36B] 13 is a diagram showing a flexure body 520M3 of a third modified example of the fifth embodiment. FIG. [Figure 37A] 13 is a diagram showing a flexure body 520M4 of a fourth modified example of the fifth embodiment. FIG. [Figure 37B] 13 is a diagram showing a flexure body 520M4 of a fourth modified example of the fifth embodiment. FIG. [Figure 38A] 13 is a diagram showing a flexure body 520M5 of a fifth modified example of the fifth embodiment. FIG. [Figure 38B] 13 is a diagram showing a flexure body 520M5 of a fifth modified example of the fifth embodiment. FIG. [Figure 38C] FIG. 13 is an exploded view of a detection device 500M5 including a flexure body 520M5 according to a fifth modified example of the fifth embodiment. [Figure 38D] FIG. 2 is an enlarged view of a portion of the detection device 500M5. [Figure 38E] FIG. 2 is an enlarged view of a portion of the detection device 500M5. [Figure 39A] 13 is a diagram showing a flexure body 520M6 of a sixth modified example of the fifth embodiment. FIG. [Figure 39B] 13 is a diagram showing a flexure body 520M6 of a sixth modified example of the fifth embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment to which the detection device of the present disclosure is applied will be described. In the following, the XYZ coordinate system is defined and described. The direction parallel to the X axis (X direction), the direction parallel to the Y axis (Y direction), and the direction parallel to the Z axis (Z direction) are mutually orthogonal. Moreover, a planar view refers to a view in the XY plane. In the following, the length, width, thickness, etc. of each part may be shown exaggerated to make the configuration easier to understand.

[0010] <Embodiment 1> FIG. 1 is a perspective view showing the detection device 100 of the first embodiment. FIG. 2 is a view showing the detection device 100 in an exploded state. FIG. 3 is a view showing a cross section taken along line AA in FIG. 1. The cross section taken along line AA is a cross section taken along a cutting plane that includes the central axis of the through-hole 123 and is parallel to the XZ plane. FIG. 4 is a view showing a cross section taken along line BB in FIG. 1. The cross section taken along line BB is a cross section taken along a cutting plane that includes the central axis of the through-hole 123 and is parallel to a plane rotated 45 degrees clockwise from the XZ plane when viewed from the +Z direction. For this reason, only the Z axis is shown in FIG. 4.

[0011] The detection device 100 includes a case 110, a strain body 120, a strain sensor 130, a wiring board 140, a communication control unit 145, and a sealing resin 150. The case 110 has a lower case 110L and an upper case 110U. In the detection device 100, the lower side (-Z direction side) is an example of a first side, and the upper side (+Z direction side) is an example of a second side. The direction connecting the first side and the second side is the up-down direction.

[0012] In the following, in addition to Figs. 1 to 4, Figs. 5 to 9 are used for explanation. Figs. 5 and 6 are diagrams showing the flexure body 120 and the strain sensor 130. Fig. 7 is a diagram showing a state in which the upper case 110U is removed from the detection device 100 and the sealing resin 150 is omitted. Figs. 8 and 9 are diagrams showing a state in which the flexure body 120 and the strain sensor 130 are arranged in the lower case 110L. In Fig. 8, the flexure body 120 and the strain sensor 130 are indicated by dashed lines.

[0013] <Overview of the detection device 100> In the detection device 100, with the bolt portion of the fastening mechanism inserted through the through hole 123 of the flexure body 120, the fastening mechanism and the fastened member come into contact with the lower surface 121A and the upper surface 121B of the flexure body 120 protruding upward and downward from the case 110. The lower surface 121A and the upper surface 121B are flat surfaces. This is to ensure that the fastening mechanism and the fastened member come into contact stably and reliably.

[0014] The detection device 100 may be used in two states, for example, where the fastening mechanism abuts against the lower surface 121A and the fastened member abuts against the upper surface 121B, and where the fastened member abuts against the lower surface 121A and the fastening mechanism abuts against the upper surface 121B. The detection device 100 detects the fastening axial force applied to the bolt when the fastening mechanism fastens the detection device 100 to the fastened member. The detection device 100 outputs a strain detection signal indicating the fastening axial force to the outside via communication control unit 145 and antenna 141 by wireless communication.

[0015] <Configuration of each part of the detection device 100> The case 110 has a lower case 110L and an upper case 110U. Since the detection device 100 performs wireless communication, the case 110 is formed of a dielectric material such as resin. The case 110 is long in the Y direction. The case 110 accommodates at least a portion of the main body 121 of the flexure body 120 along the outer surface 121C of the main body 121. The reason that the case 110 accommodates at least a portion of the main body 121 of the flexure body 120 is that the lower end and the upper end of the main body 121 protrude from the case 110.

[0016] The lower case 110L has a bottom plate portion 111, a lower surface 111L, a side wall 111S, an opening 112L, and a rib 113L. The lower surface 111L is an example of a first surface, and the bottom plate portion 111 of the lower case 110L having the lower surface 111L is an example of a first wall portion. The opening 112L is an example of a first opening. The rib 113L is an example of an opposing wall portion.

[0017] The lower surface 111L is the lower surface of the detection device 100, and is also the lower surface of the case 110. However, the lower surface 121A of the strain body 120 protrudes downward more than the lower surface 111L. The side wall 111S is provided along the outer edge of the bottom plate portion 111, and extends from the bottom plate portion 111 in the +Z direction.

[0018] The lower case 110L has an opening 112L (see FIGS. 2 to 4 and 8) in the center of the -Y direction side portion of the bottom plate portion 111 that houses the flexure body 120. The opening 112L is an octagonal opening with the four corners of a square in a plan view chamfered with gentle convex curves, and has an opening shape that matches the planar shape of the lower end portion of the main body portion 121 of the flexure body 120.

[0019] The opening 112L and the rib 113L, together with the opening 112U of the upper case 110U, form an accommodation section which is a space that accommodates the strain body 120. The space surrounded by the opening 112L communicates (is connected) with the space surrounded by the rib 113L, and the space surrounded by the rib 113L communicates (is connected) with the space surrounded by the opening 112U.

[0020] 3, 4, and 8, the lower end of the main body 121 of the flexure body 120 is inserted into the opening 112L. The size and shape of the opening 112L in a plan view are adjusted so that almost no gap is generated between the outer surface of the lower end of the main body 121 and the opening 112L when the lower end of the main body 121 of the flexure body 120 is inserted therethrough.

[0021] 7 and 8, the rib 113L is provided along the edge of the opening 112L and extends upward from the upper surface of the bottom plate portion 111. The rib 113L faces the outer surface 121C of the main body portion 121 of the flexure body 120 when the flexure body 120 is placed in the space (accommodation portion) surrounded by the ribs 113L of the lower case 110L.

[0022] The height of the rib 113L relative to the bottom plate portion 111 is equal to the height of the side wall 111S relative to the bottom plate portion 111. The rib 113L has recesses 113LA (see FIGS. 4 and 7 to 9) recessed outward in a plan view and cutout portions 113LB (see FIGS. 7 to 9) at four locations on the ±X direction sides and ±Y direction sides. The recesses 113LA are part of the rib 113L and are recessed outward in a plan view further than the portions of the rib 113L where the recesses 113LA are not formed.

[0023] The four recesses 113LA respectively accommodate the four protrusions 122 of the flexure body 120. An engagement portion 111A is provided below the recess 113LA, where the bottom plate portion 111 extends toward the center of the opening 112L. The engagement portion 111A overlaps with the protrusion 122 of the flexure body 120 in a plan view, and protrudes toward the outer surface of the main body portion 121 of the flexure body 120 beyond the rib 113L. The engagement portion 111A engages with the lower end of the protrusion 122 to prevent the flexure body 120 from falling off. At least one recess 113LA is required, and may be provided in accordance with the number of the protrusions 122.

[0024] The cutout portion 113LB is provided in a section between two adjacent recesses 113LA of the rib 113L. The cutout portion 113LB is a portion cut out from the upper end of the rib 113L to pass a signal line 145A (see FIG. 7) that connects the communication control unit 145 and the four strain sensors 130. Note that instead of the cutout portion 113LB, a hole portion (through hole) through which the signal line 145A passes may be provided.

[0025] As shown in FIGS. 2 and 7, the lower case 110L accommodates the wiring board 140 on the +Y direction side of the portion where the strain body 120 is disposed.

[0026] As shown in Figs. 1 and 2, the upper case 110U has a shape similar to that of the bottom plate portion 111 of the lower case 110L in a plan view, and has an upper surface 111U and an opening 112U. The upper case 110U is flat and is an example of a second wall portion. The upper surface 111U is an example of a second surface, and the opening 112U is an example of a second opening. The upper surface 111U is the upper surface of the detection device 100, and is also the upper surface of the case 110. However, the upper surface 121B of the strain body 120 protrudes upwards more than the upper surface 111U.

[0027] The opening 112U is formed at the same position as the opening 112L of the lower case 110L in a plan view, and has the same opening shape. The space surrounded by the opening 112U communicates with the space surrounded by the rib 113L when the upper case 110U is attached to the lower case 110L, as shown in FIG.

[0028] The upper end of the main body 121 of the flexure body 120 is inserted into the opening 112U. The size and shape of the opening 112U in plan view are adjusted so that almost no gap is generated between the outer surface of the upper end of the main body 121 and the opening 112U when the upper end of the main body 121 of the flexure body 120 is inserted therethrough.

[0029] As shown in Fig. 2, the upper case 110U is fixed to the lower case 110L by inserting the screws 115 into the screw holes and fastening the screws 115 to the screw holes of the lower case 110L with the strain body 120 and the wiring board 140 with the communication control unit 145 mounted inside the lower case 110L. The upper case 110U is a plate-shaped upper cover for the lower case 110L. When the strain body 120 and the wiring board 140 with the communication control unit 145 mounted are accommodated in the lower case 110L, the detection device 100 is completed by closing the top of the lower case 110L with the upper case 110U. In this way, the upper case 110U is simply an upper lid, and the lower case 110L can accommodate the flexure body 120 and the wiring board 140 on which the communication control unit 145 is mounted, and the engagement portion 111A prevents the flexure body 120 from falling off. This makes it easy to assemble the detection device 100. Note that the upper case 110U is not limited to a plate-shaped upper lid, and may have a side wall (a side wall extending downward) like the side wall 111S of the lower case 110L.

[0030] The flexure body 120 has a main body 121, four protrusions 122, and a through hole 123. The flexure body 120 is preferably made of a metal material such as stainless steel.

[0031] The main body 121 is a portion surrounding the through hole 123, and has a lower surface 121A located at the lower end, an upper surface 121B located at the upper end, and an outer surface 121C. The lower surface 121A is an example of a first end surface, and the upper surface 121B is an example of a second end surface. In the main body 121, the lower end portion on the lower side where the lower surface 121A is located is an example of a first end portion, and the upper end portion on the upper side where the upper surface 121B is located is an example of a second end portion. The outer surface 121C is an example of a first outer surface. The main body 121 is an octagonal shape in plan view, with the four corners of a square chamfered with gentle convex curves, similar to the openings 112L and 112U, and a circular through hole 123 is located in the center.

[0032] 3 and 4, a lower end of the main body 121 is inserted into the opening 112L of the lower case 110L, and a lower surface 121A protrudes downward beyond the lower surface 111L of the lower case 110L. An upper end of the main body 121 is inserted into the opening 112U of the upper case 110U, and an upper surface 121B protrudes upward beyond the upper surface 111U of the upper case 110U.

[0033] The outer surface 121C is an outer side surface of the main body 121, and faces the ribs 113L when the strain body 120 is disposed in a space surrounded by the ribs 113L of the lower case 110L. Convex portions 122 are provided at four corners of the outer surface 121C on the ±X direction sides and the ±Y direction sides.

[0034] 5 and 6, the outer side surface 121C has four flat surfaces 121C1 in a portion where the four protrusions 122 are not provided. Two of the four flat surfaces 121C1 are parallel to a plane rotated 45 degrees clockwise when viewed from the +Z direction from the XZ plane, and the remaining two are parallel to a plane rotated 45 degrees counterclockwise when viewed from the +Z direction from the XZ plane.

[0035] The protrusion 122 protrudes outward from the outer side surface 121C excluding the flat surface 121C1 in a plan view, and is located above the lower surface 121A and below the upper surface 121B in the vertical direction. Therefore, the outer side surfaces 121C are located above and below the protrusion 122, and there is a step between the protrusion 122 and the lower surface 121A, and there is a step between the protrusion 122 and the upper surface 121B. As shown in Fig. 5, both ends of the protrusion 122 in a plan view are chamfered.

[0036] When the flexure body 120 is disposed in a space surrounded by the ribs 113L of the lower case 110L, the convex portion 122 is housed in the concave portion 113LA of the lower case 110L. This makes it possible to prevent the flexure body 120 from rotating relative to the case 110. In this state, the lower surface of the convex portion 122 engages with the engagement portion 111A. In this state, the convex portion 122 overlaps with the engagement portion 111A in a plan view. This makes it possible to prevent the flexure body 120 from falling off the opening 112L. Note that the number of the convex portion 122 needs to be at least one.

[0037] Through hole 123 penetrates through the center of main body 121 in a plan view to connect lower surface 121A and upper surface 121B. Since a bolt portion of a fastening mechanism is inserted through through hole 123, the through hole 123 has an opening size that matches the planar size of the bolt portion. Through hole 123 is a cylindrical hole portion, and connects lower surface 121A and upper surface 121B of strain body 120.

[0038] When the fastening mechanism and the fastened member are in contact with the lower surface 121A and the upper surface 121B of such a flexure body 120, a fastening axial force is applied in the direction penetrating the through hole 123 (Z direction), and the flexure body 120 is compressed in the vertical direction. As a result, the flexure body 120 bends so that the outer surface 121C bulges outward, causing distortion.

[0039] As shown in FIGS. 5 and 6, the strain sensors 130 are provided on four flat surfaces 121C1 of the outer surface 121C of the main body 121 of the strain generating body 120, on which the four protrusions 122 are not provided.

[0040] The strain sensor 130 has one or more strain detection elements and detects the strain of the strain generating body 120. For example, each of the strain detection elements is a strain resistance element whose resistance value changes according to the amount of strain. Four strain detection elements may be provided and connected in a bridge shape.

[0041] The strain detection element may be formed on the flat surface 121C1 by printing a cermet or a composite resistor whose binder is a synthetic resin. The strain detection element can be easily and reliably installed at a predetermined installation position on the flat surface 121C1. In particular, since the printing, drying, and curing of the strain detection element can be performed collectively on the multiple flexure bodies 120 while the multiple flexure bodies 120 are arranged in a row, the strain detection element can be easily and reliably installed on the multiple flexure bodies 120.

[0042] Also, for example, the strain detection element may be mounted on a rigid or flexible substrate and attached to the flat surface 121C1 together with the rigid or flexible substrate. In this case, since the installation surface is flat, the strain detection element can be easily and reliably installed at a predetermined installation position on the flat surface 121C1.

[0043] As an example, wiring board 140 is a wiring board conforming to the FR-4 (Flame Retardant type 4) standard, etc. Wiring board 140 is Y-shaped in a plan view, is housed in lower case 110L, and is fixed to lower case 110L with screws 143.

[0044] An antenna 141 is formed on the upper surface of the wiring board 140. The antenna 141 is, for example, a monopole antenna, and is connected to the communication control unit 145 via a wiring. The antenna 141 receives radio waves emitted from the reader device of the detection device 100 and transmits them to the communication control unit 145. The antenna 141 also emits a distortion detection signal output by the communication control unit 145.

[0045] The communication control unit 145 is connected to the four strain sensors 130 and the antenna 141 via wiring. A signal line 145A (wiring) that connects the communication control unit 145 and the four strain sensors 130 passes through a notch 113LB of a rib 113L of the lower case 110L, as shown in FIG.

[0046] The communication control unit 145 incorporates a control unit that generates a strain detection signal representing the degree of strain of the flexure body 120 based on the output of the strain sensor 130, and a communication unit that performs wireless communication using the antenna 141. The communication unit supplies power received by the antenna 141 from the reader device of the detection device 100 to the control unit to operate the control unit. The control unit generates a strain detection signal representing the degree of strain of the flexure body 120 and transmits it to the communication unit. The communication unit radiates the strain detection signal through the antenna 141. The radiated strain detection signal is received by the reader device of the detection device 100.

[0047] As shown in Figs. 3 and 4, the sealing resin 150 is an example of a filler filled between the rib 113L of the lower case 110L and the flexure body 120. For example, urethane foam or the like can be used as the sealing resin 150. As an example, urethane foam may be injected between the rib 113L and the flexure body 120. By providing the sealing resin 150, the cutout portion 113LB of the rib 113L is sealed. Also, the gap between the lower case 110L and the upper case 110U and the gap between the openings 112L and 112U and the flexure body 120 can be sealed.

[0048] By providing such sealing resin 150, the internal space of the case 110 can be sealed, and the flexure body 120 can be more firmly fixed to the case 110. Note that, for example, a spacer made of a sponge or the like may be provided between the flexure body 120 and the case 110, such as between the engagement portion 111A below the recess 113LA and the protrusion 122.

[0049] <Usage state of the detection device 100> Fig. 10 is a diagram showing an example of a state in which the detection device 100 is used. Fig. 10 shows a fixing part 10, a fastening mechanism 20, and a fastened member 30. The fixing part 10 is a part of a structure such as a building, a road, a tunnel, or a bridge pier, or a member fixedly attached to a structure. A flat fastened member 30 is fixed to an attachment surface 11 of the fixing part 10 by fastening a bolt 21 and a nut 22 of the fastening mechanism 20. The bolt 21 has a bolt shaft 21A on which a thread is formed, and a head 21B. The fixing part 10 and the fastened member 30 have a through hole through which the bolt shaft 21A passes.

[0050] In the example shown in Fig. 10, the detection device 100 is provided between the nut 22 and the fastened member 30. A bolt shaft 21A extending upward from the lower surface 12 opposite to the mounting surface 11 of the fixed part 10 is inserted into the through hole 123 (see Fig. 1) of the fastened member 30 and the strain body 120 of the detection device 100. The head 21B of the bolt 21 is located on the lower surface 12 side of the fixed part 10. The nut 22 is screwed onto the bolt shaft 21A from the tip end side of the bolt shaft 21A. The head 21B of the bolt 21 may be embedded and fixed in the fixed part 10.

[0051] In the example shown in Fig. 10, when the bolt 21 and the nut 22 are fastened, the fastened member 30 and the detection device 100 are fixed to the fixing part 10. At this time, the lower surface 121A (see Figs. 3 and 4) of the main body 121 of the flexure body 120 of the detection device 100 abuts against the upper surface 31 of the fastened member 30, and the upper surface 121B (see Figs. 3 and 4) of the main body 121 abuts against the lower surface of the nut 22. Therefore, a fastening axial force in the axial direction (Z direction) of the bolt shaft 21A is applied to the flexure body 120. Here, the lower surface 121A of the main body 121 of the flexure body 120 protrudes downward from the lower surface 111L of the lower case 110L, and the upper surface 121B protrudes upward from the upper surface 111U of the upper case 110U. For this reason, only the lower surface 121A of the main body 121 of the flexure body 120 abuts against the upper surface 31 of the fastened member 30, and the lower surface 111L of the lower case 110L does not abut. Also, only the upper surface 121B of the main body 121 of the flexure body 120 abuts against the lower surface of the nut 22, and the upper surface 111U of the upper case 110U does not abut. With this configuration, the flexure body 120 can reliably receive the fastening axial force applied from the nut 22.

[0052] As a result, a strain is generated in the strain body 120 according to the fastening torque of the nut 22. The strain generated in the strain body 120 is detected by the four strain sensors 130 of the detection device 100. Based on the strain (change in the resistance value of the strain detection element) detected by each of the four strain sensors 130, a control unit of the communication control unit 145 generates a strain detection signal according to the fastening torque of the nut 22. The communication unit of the communication control unit 145 radiates the strain detection signal to the outside of the case 110 through the antenna 141. The reader device of the detection device 100 can determine the fastening state of the nut 22 based on the voltage value represented by the strain detection signal received from the detection device 100.

[0053] In the above, as an example, the detection device 100 does not include a battery or a memory, generates power from a signal received from a reader device using an electromotive coil or the like, and the communication control unit 145 transmits a distortion detection signal to the reader device using the generated power. However, the present invention is not limited to this, and the detection device 100 may be configured to include at least one of a battery and a memory.

[0054] <Effects> As described above, the flexure body 120 has the convex portion 122 that protrudes outward from the outer surface 121C excluding the flat surface 121C1 of the main body 121 in a plan view, and the case 110 has the rib 113L facing the outer surface 121C, and the rib 113L has the recess 113LA that is recessed outward in a plan view and accommodates the convex portion 122. Therefore, the convex portion 122 engages with the recess 113LA, and rotation of the flexure body 120 with respect to the case 110 can be suppressed.

[0055] Therefore, it is possible to provide a detection device 100 in which the rotation of the strain body 120 is suppressed.

[0056] The case 110 has a bottom plate 111 having a lower surface 111L located on the lower side, an opening 112L provided in the bottom plate 111, an upper case 110U having an upper surface 111U located on the upper side, and an opening 112U provided in the upper case 110U. The opening 112L, the opposing wall 113L, and the opening 112U form a housing portion that houses at least a part of the main body 131 of the flexure body 120 except for the lower end and the upper end. A lower surface 121A of the lower end of the flexure body 120 is exposed from the opening 112L and protrudes downward from the lower surface 111L in the extension direction of the through hole 123. An upper surface 121B of the upper end of the flexure body 120 is exposed from the opening 112U and protrudes upward from the upper surface 111U in the extension direction of the through hole 123.

[0057] For this reason, only the lower surface 121A of the main body 121 of the flexure body 120 abuts on the upper surface 31 of the fastened member 30, and the lower surface 111L of the lower case 110L does not abut on it. Also, only the upper surface 121B of the main body 121 of the flexure body 120 abuts on the lower surface of the nut 22, and the upper surface 111U of the upper case 110U does not abut on it.

[0058] Therefore, the strain body 120 can reliably receive the fastening axial force applied from the nut 22, and a detection device 100 can be provided in which rotation of the strain body 120 is suppressed.

[0059] In addition, the lower surface 121A at the lower end and the upper surface 121B at the upper end of the flexure body 120 are flat surfaces. Therefore, the flexure body 120 can more reliably receive the fastening axial force applied from the nut 22 by the flat lower surface 121A and upper surface 121B, and it is possible to provide a detection device 100 in which the rotation of the flexure body 120 is suppressed.

[0060] Further, the lower surface 121A at the lower end abuts against either the nut 22 of the fastening mechanism 20 or the fastened member 30 fastened by the fastening mechanism 20, and the upper surface 121B at the upper end abuts against the other of the nut 22 of the fastening mechanism 20 or the fastened member 30 fastened by the fastening mechanism 20. Therefore, by the lower surface 121A and the upper surface 121B abutting against the nut 22 of the fastening mechanism 20 and the fastened member 30 fastened by the fastening mechanism 20, the fastening axial force can be more reliably received.

[0061] Furthermore, the protrusion 122 is located above the lower surface 121A at the lower end and below the upper surface 121B at the upper end in the extending direction of the through hole 123, and there is a step between the protrusion 122 and the lower surface 121A, and there is a step between the protrusion 122 and the upper surface 121B. Therefore, by engaging the protrusion 122 with the recess 113LA, it is possible to suppress the rotation of the strain body 120 relative to the case 110, and to realize a configuration in which the lower surface 121A and the upper surface 121B abut against the nut 22 of the fastening mechanism 20 and the fastened member 30 fastened by the fastening mechanism 20, and it is possible to provide a detection device 100 that achieves both suppression of the rotation of the strain body 120 and reliable transmission of the fastening axial force.

[0062] Moreover, the case 110 further has an engagement portion 111A that overlaps the protrusion 122 in a plan view, protrudes toward the outer surface side beyond the rib 113L, and engages with a portion on the lower end side of the protrusion 122. This makes it possible to prevent the strain body 120 from falling off the opening 112L, and to provide a detection device 100 that is easy to assemble.

[0063] Moreover, the case 110 further has a notch 113LB or a hole provided in a part of the rib 113L, through which a signal line 145A connected to the strain sensor 130 passes. Therefore, a configuration can be realized in which a signal output by the strain sensor 130 attached to the strain element 120 located outside the closed space of the case 110 can be reliably transmitted to the communication control unit 145 located inside the closed space of the case 110.

[0064] Furthermore, since the sealing resin 150 is further included to be filled between the outer surface 121C of the flexure body 120 and the rib 113L of the case 110, the notch 113LB or hole of the rib 113L, the gap between the lower case 110L and the upper case 110U, the gap between the openings 112L and 112U and the flexure body 120, etc. are sealed. Therefore, the airtightness of the case 110, which houses the wiring board 140 and the communication control unit 145, etc., can be maintained for a long period of time, and the flexure body 120 can be fixed more firmly to the case 110, thereby providing a detection device 100 capable of stably detecting the fastening axial force for a long period of time.

[0065] <Modification of the first embodiment> Here, the differences from the detection device 100 of embodiment 1 will be mainly described. The same components as those of the detection device 100 of embodiment 1 will be given the same reference numerals, and the description thereof will be omitted. Also, in the drawings, only some of the reference numerals will be shown.

[0066] <Detection Device 100A of First Modification> Fig. 11A is a diagram showing a detection device 100A according to a first modified example of embodiment 1. Fig. 11B is a diagram showing a disassembled state of the detection device 100A.

[0067] The detection device 100A is configured to be disk-shaped as a whole. The lower case 110L and the upper case 110U of the case 110 are the lower case 110L and the upper case 110U shown in Fig. 2 made circular in plan view, and the wiring board 140A is the wiring board 140 shown in Fig. 2 made annular. The other configurations are the same as those of the detection device 100 of the first embodiment.

[0068] <Detection Device 100B of Second Modification> Fig. 12A is a diagram showing a detection device 100B according to a first modified example of embodiment 1. Fig. 12B is a diagram showing a disassembled state of detection device 100B.

[0069] The detection device 100B includes a flexure body 120B having a smaller outer diameter at the upper end of a main body 121, instead of the flexure body 120 of the detection device 100 of embodiment 1. The inner diameter of the upper surface 121B of the main body 121 of the flexure body 120 is equal to the inner diameter of the upper surface 121B of the main body 121 of the flexure body 120 of the detection device 100 of embodiment 1, but the outer diameter is smaller. Due to this change, the opening diameter of the opening 112U of the upper case 110U is smaller.

[0070] The strain body 120 of the detection device 100B has a smaller outer diameter at the upper end of the main body 121, so that there is a step between the lower end and the upper end of the main body 121. The other configurations are the same as those of the detection device 100 of the first embodiment.

[0071] <Third Modified Strain Body 120C> 13A and 13B are diagrams showing a flexure body 120C of a third modified example. The flexure body 120C differs from the protrusion 122 shown in FIG. 5 in that both ends of the protrusion 122C in plan view are not chamfered. Such a flexure body 120C may be used in place of the flexure body 120.

[0072] <Fourth Modification of Strain Body 120D> 14A and 14B are diagrams showing a flexure body 120D of a fourth modified example. The flexure body 120D has a configuration in which the convex portions 122C of the flexure body 120C shown in FIGS. 13A and 13B are replaced with concave portions 122D.

[0073] The main body 121 of the flexure body 120D is an annular member, with a recess 122D provided on the outer periphery and a through hole 123 provided in the center. The recesses 122D are provided at four locations at 90 degree intervals in the circumferential direction of the annular flexure body 120, and are provided at two locations, one above the other, on the lower surface 121A side and the other above the upper surface 121B side. The recesses 122D are recessed radially inward from the outer surface 121C of the main body 121.

[0074] When using such a flexure body 120D, the lower case 110L only needs to have a convex portion 113LD instead of the concave portion 113LA (see FIGS. 3, 8, and 9). Two convex portions 113LD are provided, one above the other, corresponding to the concave portion 122D. Such a flexure body 120D may be used instead of the flexure body 120.

[0075] <The strain body 120E of the fifth modified example> 15A and 15B are diagrams showing a flexure body 120E of a fifth modified example. The flexure body 120E has a configuration in which the convex portion 122C of the flexure body 120C shown in FIGS. 13A and 13B is replaced with a concave portion 122E.

[0076] 14A and 14B in the circumferential direction of the flexure body 120E. Such a flexure body 120E may be used in place of the flexure body 120.

[0077] <Second embodiment> 16 and 17 are perspective views showing the detection device 200 of the second embodiment. FIG. 18 and FIG. 19 are views showing the state in which the detection device 200 is disassembled. FIG. 16 and FIG. 18 show a state seen from an obliquely upper side, and FIG. 17 and FIG. 19 show a state seen from an obliquely lower side. FIG. 20 and FIG. 21 are views showing a cross section along the CC arrow in FIG. 16. The CC cross section is a cross section in a cutting plane that includes the central axis of the through hole 223 and is parallel to the XZ plane. FIG. 22 is a view showing a cross section along the DD arrow in FIG. 16. The DD cross section is a cross section in a cutting plane that includes the central axis of the through hole 223 and is parallel to a plane that is rotated 45 degrees clockwise from the XZ plane when viewed from the +Z direction. FIG. 23 is a view showing a state in which the upper case 110U is removed from the detection device 200 and the sealing resin 150 is omitted. FIG. 24 is a view showing an enlarged portion of FIG. 23.

[0078] The following description will focus on the differences from the detection device 100 of embodiment 1. Components similar to those of the detection device 100 of embodiment 1 are given the same reference numerals, and descriptions thereof will be omitted.

[0079] The detection device 200 includes a case 110, a strain body 220, a strain sensor 130, a wiring board 140, a communication control unit 145, and a spacer 155. The detection device 200 includes a sealing resin similar to the sealing resin 150 of the detection device 100 of the first embodiment, but is not illustrated here.

[0080] <Configuration of each part of the detection device 200> The case 110 has a lower case 110L and an upper case 110U. In the second embodiment, the lower portion of the flexure body 220 is larger in plan view than the lower portion of the flexure body 120 in the first embodiment, so the ribs 113L and recesses 113LA of the lower case 110L in the second embodiment extend further outward in plan view than the ribs 113L and recesses 113LA of the lower case 110L in the first embodiment. Also, the opening 112L of the lower case 110L in the second embodiment is larger in plan view than the opening 112L of the lower case 110L in the first embodiment.

[0081] The flexure body 220 has a main body 221, four protrusions 222, and a through hole 223. The flexure body 220 is preferably made of a metal material such as stainless steel. A bolt is inserted into the through hole 223.

[0082] The main body portion 221 is a portion that surrounds the through hole 223, and has a base portion 224, an extension portion 225, and a surrounding wall portion 226. The base portion 224 is a cylindrical portion that surrounds the through hole 223.

[0083] The base 224 has a lower surface 224A, an upper surface 224B, and an outer surface 224C. The upper surface 224B is an example of a second end surface, and abuts against the lower surface of the nut 22 in the use state shown in Fig. 10. The lower end where the lower surface 224A of the base 224 is located is an example of a third end surface, and the lower surface 224A is an example of a third end surface. The upper end where the upper surface 224B is located is an example of a second end surface. The outer surface 224C is an example of a second outer surface.

[0084] The extension portion 225 extends outward from the outer portion of the base portion 224 in a plan view, and is an annular portion surrounding the periphery of the base portion 224. As can be seen by comparing Fig. 21 and Fig. 22, the four protrusions 222 protrude outward from an outer surface 225C of the extension portion 225. The outer surface 225C of the extension portion 225 is an example of a first outer surface. As shown in Fig. 22, the outer surface 225C faces the rib 113L of the lower case 110L.

[0085] A cylindrical surrounding wall portion 226 is provided below the extending portion 225. As shown in Fig. 22, an outer surface 225C of the extending portion 225 and an outer surface 226C of the surrounding wall portion 226 are located at the same position in the radial direction of the through hole 223, and the outer surface 225C and the outer surface 226C form the outer peripheral surface of a virtual cylinder surrounded by the outer surfaces 225C and 226C of the extending portion 225 and the surrounding wall portion 226.

[0086] A groove 225A is formed on the lower surface side of the extension portion 225 between the lower end of the base portion 224 and the lower end of the surrounding wall portion 226. As shown in FIG. 23, four strain sensors 130 are arranged on the upper surface 225B (see FIGS. 20 and 21) of the extension portion 225. Four spacers 155 (see FIGS. 18, 19, and 20) are sandwiched between the upper surface 225B (see FIGS. 20 and 21) and the upper case 110U. The spacers 155 are, for example, urethane sponge. On the upper surface 225B of the extension portion 225, the four strain sensors 130 and the four spacers 155 are arranged alternately around the through hole 223.

[0087] The surrounding wall portion 226 is a cylindrical portion that protrudes downward in the extension direction (Z direction) of the through hole 223 from a lower portion of the extending portion 225 and surrounds the outer side surface 224C with a gap between it and the outer side surface 224C of the base portion 224. With this configuration, a groove 225A is formed between the lower end portion of the base portion 224 and the lower end portion of the surrounding wall portion 226.

[0088] The surrounding wall 226 has a lower surface 226A and an outer surface 226C. The lower surface 226A is an example of a first end surface, and protrudes downward from the lower surface 224A of the base 224. The lower surface 226A corresponds to the lower surface 121A of the strain body 120 in the detection device 100 of the first embodiment, and contacts the upper surface 31 of the fastened member 30 shown in Fig. 10 in the used state. The lower surface 224A of the base 224 is located above the lower surface 226A of the surrounding wall 226, and therefore does not contact the upper surface 31 of the fastened member 30 shown in Fig. 10 in the used state.

[0089] In such a strain body 220, a cross section perpendicular to the radial direction of the through hole 223 of the main body 221 having the base 224, the extension 225, and the surrounding wall 226 is h-shaped as shown in Fig. 21 and Fig. 22. When the detection device 200 is used instead of the detection device 100 shown in Fig. 10, the upper surface 224B abuts on the lower surface of the nut 22, and the lower surface 226A abuts on the upper surface 31 of the fastened member 30 in the used state. Moreover, the lower surface 224A of the base 224 does not abut on the upper surface 31 of the fastened member 30.

[0090] For this reason, in a used state, when the fastening axial force of the nut 22 is applied, a force is applied between the upper surface 224B and the lower surface 226A of the strain body 220. Since the surrounding wall portion 226 is located below the extension portion 225 extending radially outward from the outer periphery of the base portion 224, the H-shaped cross-sectional structure of the strain body 220 functions as a spring. In Fig. 21 and Fig. 22, when the fastening axial force of the nut 22 is applied to the upper surface 224B in the Z direction, the extension portion 225 bends with respect to the XY plane, causing distortion in the strain body 220.

[0091] In the second embodiment, the strain sensors 130 are disposed on the upper surface 225B of the extension portion 225. Therefore, when the fastening axial force of the nut 22 is applied, the extension portion 225 bends, and the strain generated in the strain body 220 is detected by the four strain sensors 130.

[0092] <Simulation results> Fig. 25 is a diagram showing the results of a simulation in which the distribution of strain is calculated when a fastening axial force is applied to the strain body 220. The shades of grayscale in Fig. 25 represent the amount (degree) of strain occurring on the surface of the strain body 220 in a direction at an angle of 45 degrees to the X-axis and Y-axis in a plan view (the direction indicated by the double arrow in Fig. 25). Although only some of the symbols are shown in Fig. 25, it can be seen that strain occurs on the upper surface 225B of the extension part 225. Therefore, the strain occurring in the strain body 220 can be detected by the strain sensor 130 arranged on the upper surface 225B of the extension part 225.

[0093] As described above, the main body 221 of the flexure body 220 has the base 224 surrounding the through hole 123, the extension 225 extending outward in a plan view from the side of the base 224, and the surrounding wall 226 protruding downward in the extending direction of the through hole 223 from a lower portion of the extension 225 and surrounding the outer surface 224C of the base 224 with a gap therebetween. The lower surface 226A of the surrounding wall 226 protrudes downward from the lower surface 224A of the base 224 in the extending direction of the through hole 223. Therefore, when the fastening axial force of the nut 22 is applied to the upper surface 224B, the extension 225 bends with respect to the XY plane, causing distortion in the flexure body 220.

[0094] The flexure body 220 has a protrusion 222 that protrudes outward from an outer surface 225C of the main body 221 in a plan view, and the case 110 has a rib 113L facing the outer surface 225C, and the rib 113L has a recess 113LA that is recessed outward in a plan view and accommodates the protrusion 222. Therefore, the protrusion 222 engages with the recess 113LA, and rotation of the flexure body 220 with respect to the case 110 can be suppressed.

[0095] Therefore, it is possible to provide a detection device 200 in which the rotation of the strain body 220 is suppressed.

[0096] <Embodiment 3> Fig. 26 is a diagram showing a flexure body 320 of the third embodiment. Fig. 26 also shows a strain sensor 130. The flexure body 320 can be used in the detection device 100 in place of the flexure body 120 of the first embodiment, as an example.

[0097] The flexure body 320 has a main body 321, four protrusions 322, and a through hole 323. The flexure body 320 is preferably made of a metal material such as stainless steel. The flexure body 320 differs from the flexure body 120 of the first embodiment in the way in which distortion occurs due to the fastening axial force. A bolt is inserted into the through hole 323.

[0098] Main body 321 is an annular member surrounding through hole 323, and has lower surface 321A and upper surface 321B. Lower surface 321A is an example of a first end surface, and upper surface 321B is an example of a second end surface. In the use state shown in FIG. 10, lower surface 321A abuts against upper surface 31 of fastened member 30, and upper surface 321B abuts against the lower surface of nut 22.

[0099] The main body 321 has a plurality of first recesses 324A recessed upward from the lower surface 321A in the extension direction of the through hole 323, and a plurality of second recesses 324B recessed downward from the upper surface 121B in the extension direction of the through hole 323. In FIG. 26, as an example, the main body 321 has four first recesses 324A and four second recesses 324B. The four first recesses 324A and the four second recesses 324B are arranged to have an overlapping section in the circumferential direction of the main body 321 surrounding the through hole 323. This is to make it easier for distortion to occur in the main body 321 in the circumferential direction.

[0100] If the first recess 324A and the second recess 324B do not have an overlapping section in the circumferential direction of the main body portion 321, the rigidity of the main body portion 321 at the boundary between the first recess 324A and the second recess 324B in the circumferential direction is increased, and distortion is less likely to occur when a fastening axial force is applied. Note that if sufficient distortion occurs in the main body portion 321 even if the first recess 324A and the second recess 324B do not have an overlapping section in the circumferential direction of the main body portion 321, the first recess 324A and the second recess 324B may not have an overlapping section.

[0101] 10, the lower surface 321A abuts against the upper surface 31 of the fastened member 30, but the four first recesses 324A do not abut against the upper surface 31 of the fastened member 30. Similarly, the upper surface 321B abuts against the lower surface of the nut 22, but the four second recesses 324B do not abut against the lower surface of the nut 22.

[0102] Therefore, when the fastening axial force of the nut 22 is applied in a used state, a force is applied between the lower surface 321A and the upper surface 321B of the elastic body 320, and the section in which the first recess 324A is present and the section in which the second recess 324B is present bend in the circumferential direction of the main body 321, causing distortion in the elastic body 320.

[0103] The four strain sensors 130 are disposed on the surfaces of the four second recesses 324B. Therefore, when the fastening axial force of the nut 22 is applied, the strain generated by the deflection of the strain body 320 is detected by the four strain sensors 130.

[0104] <Simulation results> FIG. 27 is a diagram showing the results of a simulation in which the distribution of strain is calculated when a fastening axial force is applied to the flexure body 320. FIG. 27 shows the distribution of strain on the upper surface side of the flexure body 320. The grayscale shading in FIG. 27 represents the amount (degree) of strain occurring on the surface of the flexure body 220 in a direction at an angle of 45 degrees to the X-axis and Y-axis in a plan view (the direction indicated by the double arrow in FIG. 27). Although only some of the symbols are shown in FIG. 27, it can be seen that the strain in the four second recesses 324B is large. Since the lower surface 321A side and the upper surface 321B side of the flexure body 320 are symmetrical, it is considered that the strain in the four first recesses 324A is similarly large. For this reason, the four strain sensors 130 arranged on the surfaces of the four second recesses 324B can detect the strain occurring in the flexure body 320.

[0105] As described above, main body 321 of flexure body 320 has a plurality of first recesses 324A provided at the lower end along the periphery of through hole 323 and recessed upward from lower surface 321A in the extension direction of through hole 323, and a plurality of second recesses 324B provided at the upper end along the periphery of through hole 323 and recessed downward from upper surface 321B in the extension direction of through hole 323. The plurality of first recesses 324A and the plurality of second recesses 324B are alternately arranged along the periphery of through hole 323.

[0106] Therefore, in a state of use, a force is applied between lower surface 321A and upper surface 321B of flexure body 320, causing distortion in flexure body 320.

[0107] The flexure body 320 has a convex portion 322 that protrudes outward from an outer surface 321C (an example of a first outer surface) of the main body 321 in a planar view, and the convex portion 322 engages with a concave portion 113LA of the case 110, thereby preventing the flexure body 320 from rotating relative to the case 110.

[0108] Therefore, it is possible to provide the detection device of the third embodiment in which the rotation of the strain body 320 is suppressed.

[0109] Furthermore, since the multiple first recesses 324A and the multiple second recesses 324B are arranged to have an overlapping section in the circumferential direction of the main body portion 321 surrounding the through hole 323, the strain body 320 becomes more easily bent in the circumferential direction, and the fastening axial force can be detected more reliably by the strain sensor 130.

[0110] <Embodiment 4> Fig. 28A and Fig. 28B are diagrams showing the flexure body 420 of the embodiment 4. Fig. 28A and Fig. 28B also show the strain sensor 130. As an example, the flexure body 420 can be used in the detection device 100 in place of the flexure body 120 of the embodiment 1. Fig. 28B shows a state in which an O-ring 460 is attached to the flexure body 420.

[0111] The flexure body 420 has a main body 421, four protrusions 422, and a through hole 423. The flexure body 420 is preferably made of a metal material such as stainless steel. A bolt is inserted into the through hole 423.

[0112] The main body 421 is an annular member surrounding the through hole 423, and has a lower surface 421A and an upper surface 421B. The lower surface 421A is an example of a first end surface, and the upper surface 421B is an example of a second end surface. In the use state shown in FIG. 10, the lower surface 421A abuts against the upper surface 31 of the fastened member 30, and the upper surface 421B abuts against the lower surface of the nut 22. The strain sensor 130 is attached to the outer surface 421C of the main body 421.

[0113] As shown in FIG. 28B, two O-rings 460 are attached to the outer surface 421C of the main body 421, one above the other. The lower O-ring 460 is an example of a first O-ring, and the upper O-ring 460 is an example of a second O-ring. The lower O-ring 460 is attached to the outer surface 421C so as to be located below the strain sensor 130, and the upper O-ring 460 is attached to the outer surface 421C so as to be located above the strain sensor 130. The two O-rings 460 are identical, and the inner diameter is slightly smaller than the outer shape of the main body 421. Therefore, the O-ring 460 is in close contact with the outer surface 421C of the main body 421 while being slightly stretched in the circumferential direction.

[0114] A case (not shown) for housing such a flexure body 420 may have a cylindrical housing portion corresponding to the outer surface 421C and recesses for housing the four protrusions 422. The flexure body 420 is attached with the O-ring 460 sandwiched between the inner surface of the housing portion of the case. That is, the O-ring 460 is compressed in the radial direction. Therefore, the strain sensor 130 is located in the space sandwiched between the two O-rings 460, one above the other, and the internal space of the case can be sealed and the flexure body 420 can be fixed more firmly to the case. In addition, since the strain sensor 130 is located in the space surrounded by the two O-rings 460, one above the other, and the case, a highly waterproof structure is obtained.

[0115] In use, the lower surface 421A abuts against the upper surface 31 (see FIG. 10) of the workpiece 30, and when a fastening axial force of the nut 22 is applied, a force is applied between the lower surface 421A and the upper surface 421B of the flexure body 420, causing distortion in the circumferential direction of the main body 421. The distortion of the flexure body 420 is detected by the four strain sensors 130.

[0116] The flexure body 420 has a convex portion 422 that protrudes outward from the outer surface 421C of the main body portion 421 in a plan view, and the convex portion 422 engages with a recess such as the recess 113LA of the case 110, thereby preventing the flexure body 420 from rotating relative to the case.

[0117] Therefore, it is possible to provide the detection device of the fourth embodiment in which the rotation of the strain body 420 is suppressed.

[0118] Furthermore, since the strain sensor 130 is positioned within the space surrounded by the upper and lower O-rings 460 and the case, a highly waterproof structure is obtained, making it possible to provide a detection device that is highly reliable over the long term.

[0119] 29A and 29B, the flexure body 420 may have a recess 421D provided around the circumferential direction of the outer surface 421C at a position on the outer surface 421C where the O-ring 460 is attached. The recess 421D is provided around the entire circumference of the outer surface 421C in accordance with the shape of the O-ring 460, above and below.

[0120] By forming such recess 421D, it is possible to suppress displacement of O-ring 460, suppress rotation of strain generating body 420, and provide a detection device with even higher reliability.

[0121] <Embodiment 5> Fig. 30A and Fig. 30B are perspective views showing the detection device 500 of the fifth embodiment. Fig. 31A is a view showing the detection device 500 in an exploded state. Fig. 31B is a view showing the flexure body 520 to which the O-ring 560 is attached. Figs. 32A and 32B are views showing the lower case 510L of the case 510 and the flexure body 520. Figs. 33A and 33B are views showing a cross section taken along the arrow EE in Figs. 30A and 30B. The cross section taken along the arrow EE is a cross section taken along a cutting plane that includes the central axis of the through hole 523 and is parallel to the XZ plane.

[0122] The detection device 500 includes a case 510, a strain sensor 520, a wiring board 540, and an O-ring 560. The strain sensor 130 is the same as the strain sensor 130 of the first embodiment. The detection device 500 includes an antenna and a communication control unit similar to the antenna 141 and the communication control unit 145 on the wiring board 540, but these are omitted here.

[0123] Case 510 has lower case 510L and upper case 510U. In detection device 500, the lower side (-Z direction side) is an example of the first side, and the upper side (+Z direction side) is an example of the second side. The direction connecting the first side and the second side is the up-down direction.

[0124] <Outline of the detection device 500> In detection device 500, with the bolt portion of the fastening mechanism inserted through through hole 523 of strain body 520, the fastening mechanism and the fastened member come into contact with lower surface 521A and upper surface 521B of strain body 520 protruding vertically from case 510. Lower surface 521A and upper surface 521B are flat surfaces. This is to enable stable and reliable contact between the fastening mechanism and the fastened member.

[0125] The detection device 500 may be used in two states, for example, when the fastening mechanism is in contact with the lower surface 521A and the fastened member is in contact with the upper surface 521B, and when the fastened member is in contact with the lower surface 521A and the fastening mechanism is in contact with the upper surface 521B. The detection device 500 detects the fastening axial force applied to the bolt when the fastening mechanism fastens the detection device 500 to the fastened member. The detection device 500 outputs a strain detection signal representing the fastening axial force to the outside via a communication control unit and an antenna by wireless communication. The fastening axial force is a force corresponding to the strain detected by the strain sensor 130. Therefore, the data representing the fastening axial force is data corresponding to the strain detected by the strain sensor 130. The detection device 500 radiates a signal including data corresponding to the strain detected by the strain sensor 130 from the communication control unit to the outside of the detection device 500 via the antenna.

[0126] <Configuration of each part of the detection device 500> Case 510 has lower case 510L and upper case 510U. Since detection device 500 performs wireless communication, case 510 is formed of a dielectric material such as resin. Case 510 has an annular shape. Case 510 houses at least a portion of main body 521 of flexure body 520 along outer surface 521C of main body 521. Case 510 houses at least a portion of main body 521 of flexure body 520 because the lower end and upper end of main body 521 protrude from case 510.

[0127] The lower case 510L has a bottom plate portion 511, a lower surface 511L, a side wall 511S, an opening 512L, and a wall portion 513L. The lower surface 511L is an example of a first surface, and the bottom plate portion 511 of the lower case 510L having the lower surface 511L is an example of a first wall portion. The opening 512L is an example of a first opening. The wall portion 513L is an example of an opposing wall portion.

[0128] The lower surface 511L is the lower surface of the detection device 500 and the lower surface of the case 510. However, the lower surface 521A of the strain body 520 protrudes downward from the lower surface 511L. The side wall 511S is provided along the outer edge of the bottom plate portion 511 and extends from the bottom plate portion 511 in the +Z direction.

[0129] The lower case 510L has an opening 512L (see FIG. 31A) in the center of the -Y direction side portion of the bottom plate portion 511 that houses the flexure body 520. The opening 512L is circular in a plan view, and has an opening shape that matches the planar shape of the lower end portion of the main body portion 521 of the flexure body 520.

[0130] The opening 512L and the wall 513L, together with the opening 512U and the wall 513U of the upper case 510U, form an accommodation section which is a space for accommodating the strain body 520. The space surrounded by the opening 512L communicates (is connected) with the space surrounded by the wall 513L, and the space surrounded by the wall 513L communicates (is connected) with the space surrounded by the wall 513U and the opening 512U. Note that the walls 513L and 513U are spaced apart in the vertical direction, but are closed at the seam between the lower case 510L and the upper case 510U.

[0131] 33A and 33B, the lower end of the main body 521 of the flexure body 520 is inserted into the opening 512L. The size and shape of the opening 512L in a plan view are adjusted so that almost no gap is generated between the outer surface of the lower end of the main body 521 and the opening 512L when the lower end of the main body 521 of the flexure body 520 is inserted therethrough.

[0132] As shown in Figures 32A, 33A, and 33B, the wall portion 513L is a cylindrical wall portion provided along the edge of the opening portion 512L, and extends upward from the upper surface of the bottom plate portion 511. The wall portion 513L expands such that the inner diameter of the inner circumferential surface on the radially inner side of the lower case 510L increases toward the upper side. That is, the inner circumferential surface of the wall portion 513L has a shape like the side surface of a truncated cone turned upside down.

[0133] The wall portion 513L faces the outer surface 521C of the main body portion 521 of the flexure body 520 in a state in which the flexure body 520 is placed in a space (accommodation portion) surrounded by the wall portion 513L of the lower case 510L. In this state, an O-ring 560 attached to the lower side of the flexure body 520 abuts against the inner circumferential surface of the wall portion 513L. The O-ring 560 is crushed between the inner circumferential surface of the wall portion 513L and the main body portion 521 of the flexure body 520. The lower O-ring 560 is at the position of the second O-ring.

[0134] The height of the wall 513L relative to the bottom plate 511 is equal to the height of the lower flange 522 of the flexure body 520 relative to the bottom plate 511 when inserted into the opening 512L. The lower flange 522 is an example of a first flange. The wall 513L has convex portions 513LA (see Figs. 32A, 32B, 33A, and 33B) that protrude inward in plan view at four locations on the ±X direction side and the ±Y direction side. The convex portions 513LA are located at the upper end of the wall 513L and are provided at four locations in the circumferential direction of the upper end of the wall 513L. The convex portions 513LA are part of the wall 513L, and at the upper end of the wall 513L, they protrude inward in the radial direction of the lower case 510L in plan view further than a portion where the convex portions 513LA are not formed.

[0135] The four convex portions 513LA come into contact with the four notches 522A of the lower flange 522 of the two flanges 522 of the flexure body 520. The inner diameter of the inner circumferential surface of the wall portion 513L increases toward the upper side, in other words, the inner diameter of the inner circumferential surface of the wall portion 513L decreases toward the lower side toward the opening portion 512L, and the lower flange 522 of the flexure body 520 is engaged therewith, thereby preventing the flexure body 520 from falling off. Note that at least one convex portion 513LA is required, and may be provided in accordance with the number of the notches 522A.

[0136] As shown in FIGS. 31A, 33A, and 33B, the lower case 510L accommodates the wiring board 540 on the radially outer side of the portion where the strain body 520 is arranged.

[0137] As shown in Figs. 31A, 33A, and 33B, the upper case 510U has a shape substantially similar to that of the lower case 510L, and has an upper surface 511U and an opening 512U. The upper case 510U has a shape obtained by inverting the lower case 510L, and is an example of a second wall portion. The upper surface 511U is an example of a second surface, and the opening 512U is an example of a second opening. The upper surface 511U is the upper surface of the detection device 500, and is the upper surface of the case 510. However, the upper surface 521B of the strain body 520 protrudes upward from the upper surface 511U.

[0138] The opening 512U is formed at the same position as the opening 512L of the lower case 510L in a plan view, and has the same opening shape. The inner peripheral surface of the wall portion 513U is in communication with the opening 512U, and the inner diameter of the inner peripheral surface of the wall portion 513U increases toward the lower side. In this way, the wall portion 513U has a shape that is like an inverted version of the wall portion 513L of the lower case 510L. The inner peripheral surface of the wall portion 513U has a shape like the side of a truncated cone.

[0139] As shown in FIGS. 33A and 33B, the space surrounded by the opening 512U and the wall 513U communicates with the space surrounded by the wall 513L and the opening 512L when the upper case 510U is attached to the lower case 510L.

[0140] The upper end of the main body 521 of the flexure body 520 is inserted into the opening 512U. The size and shape of the opening 512U in a plan view are adjusted so that almost no gap is generated between the outer surface of the upper end of the main body 521 and the opening 512U when the upper end of the main body 521 of the flexure body 520 is inserted therethrough.

[0141] In this state, O-ring 560 attached to the upper side of flexure body 520 abuts against the inner circumferential surface of wall portion 513U. O-ring 560 is crushed between the inner circumferential surface of wall portion 513U and main body portion 521 of flexure body 520. Upper O-ring 560 is an example of a second O-ring.

[0142] The inner diameter of the inner circumferential surface of the wall portion 513U decreases toward the upper side toward the opening portion 512U, and the upper flange 522 of the flexure body 520 is engaged therewith, so that the flexure body 520 does not slip out upward. The upper flange 522 is an example of a second flange.

[0143] As an example, unlike the wall 513L of the lower case 510L, the wall 513U does not have a convex portion corresponding to the convex portion 513LA. Therefore, the notch 522A of the upper flange 522 of the flexure body 520 does not engage with the upper case 510U. However, a convex portion corresponding to the convex portion 513LA may be provided on the wall 513U of the upper case 510U to engage the notch 522A of the upper flange 522 of the flexure body 520 with the upper case 510U. Also, the wall 513U of the upper case 510U may have a convex portion without providing the convex portion 513LA of the wall 513L of the lower case 510L.

[0144] As shown in Figs. 33A and 33B, the upper case 510U is fixed to the lower case 510L as shown in Figs. 30A and 30B by inserting screws 515 into the screw holes and fastening the screws 515 to the screw holes of the lower case 510L in a state in which the strain body 520 and the wiring board 540 on which the communication control unit and the antenna are mounted are accommodated in the internal space surrounded by the lower case 510L. The detection device 500 is completed by fastening the lower case 510L and the upper case 510U with the screws 515 in a state in which the strain body 520 and the wiring board 540 on which the communication control unit and the antenna are mounted are accommodated in the internal space between the lower case 510L. At this time, the opening 512L of the lower case 510L and the opening 512U of the upper case 510U are sealed by two O-rings 560. 31A, an O-ring 575A is sandwiched between the outer radial joint of the lower case 510L and the upper case 510U, and an O-ring 575B is sandwiched between the screw hole through which the screw 515 passes. Therefore, when the flexure body 520 is attached to the lower case 510L and the upper case 510U, the space between the lower case 510L, the upper case 510U, and the flexure body 520 is sealed by the O-ring 560, and the joint between the lower case 510L and the upper case 510U is sealed by the O-rings 575A and 575B. In this way, the detection device 500 has a waterproof structure.

[0145] The flexure body 520 has a main body 521, two flanges 522, four cutouts 522A, and a through hole 523. The flexure body 520 is preferably made of a metal material such as stainless steel.

[0146] The main body 521 is a portion surrounding the through hole 523, and has a lower surface 521A located at the lower end, an upper surface 521B located at the upper end, and an outer surface 521C. The lower surface 521A is an example of a first end surface, and the upper surface 521B is an example of a second end surface. In the main body 521, the lower end portion on the lower side where the lower surface 521A is located is an example of a first end portion, and the upper end portion on the upper side where the upper surface 521B is located is an example of a second end portion. The outer surface 521C is an example of a first outer surface. The strain body 520 is an octagonal shape in plan view, with the four corners of the square being chamfered with gentle convex curves, and a circular through hole 523 is located in the center.

[0147] 33A and 33B, a lower end of main body 521 is inserted into opening 512L of lower case 510L, and lower surface 521A protrudes downward beyond lower surface 511L of lower case 510L. An upper end of main body 521 is inserted into opening 512U of upper case 510U, and upper surface 521B protrudes upward beyond upper surface 511U of upper case 510U, as shown in FIG.

[0148] The outer surface 521C is an outer side surface of the main body 521, and faces the walls 513L and 513U when the flexure body 520 is disposed in a space surrounded by the wall 513L of the lower case 510L and the wall 513U of the upper case 510U. Two flanges 522 are provided at two locations, upper and lower, on the outer surface 521C. The flanges 522 are annular protrusions and protrude radially outward from the outer surface 521C. Four portions on the ±X direction side and ±Y direction side of each flange 522 are provided with notches 522A. The notches 522A are portions obtained by cutting out the outer edge of the flange 522, which is an annular protrusion, and are offset radially inward from portions of the outer edge of the flange 522 where the notches 522A are not provided.

[0149] As described above, the notch 522A of the lower flange 522 engages with the convex portion 513LA of the wall portion 513L of the lower case 510L, but the notch 522A of the upper flange 522 does not engage with the wall portion 513L of the upper case 510U. The notch 522A of the upper flange 522 exists because it is formed at the same time when the notch 522A of the lower flange 522 is formed. The notch 522A does not have to be provided in the upper flange 522. Also, although a form in which two flanges are provided on the main body portion 521 of the strain body 520 will be described here, three or more flanges 522 may be provided in the axial direction (Z direction) of the main body portion 521.

[0150] With the flexure body 520 disposed in the space surrounded by the wall portion 513L of the lower case 510L and the wall portion 513U of the upper case 510U, the notch portion 522A engages with the convex portion 513LA of the lower case 510L. This makes it possible to prevent the flexure body 520 from rotating relative to the case 510. An upper O-ring 560 is fitted onto the upper side of the upper flange 522, and a lower O-ring 560 is fitted onto the lower side of the lower flange 522.

[0151] The lower O-ring 560 is crushed between the lower flange 522 and the inner circumferential surface of the wall portion 513L of the lower case 510L, and the upper O-ring 560 is crushed between the upper flange 522 and the inner circumferential surface of the wall portion 513U of the upper case 510U. In this state, the two upper and lower flanges 522 are held by the upper and lower wall portions 513L and 513U via the O-ring 560. This makes it possible to prevent the strain body 520 from slipping out of the openings 512L and 512U. The number of the notches 522A needs to be at least one.

[0152] Through hole 523 penetrates through the center of main body 521 in a plan view to connect lower surface 521A and upper surface 521B. Since a bolt portion of a fastening mechanism is inserted through through hole 523, the through hole 523 has an opening size that matches the planar size of the bolt portion. Through hole 523 is a cylindrical hole portion, and connects lower surface 521A and upper surface 521B of strain body 520.

[0153] When the fastening mechanism and the fastened member are in contact with the lower surface 521A and the upper surface 521B of such a strain body 520, a fastening axial force is applied in the direction penetrating the through hole 523 (Z direction), and the strain body 520 is compressed in the vertical direction. As a result, the strain body 520 bends so that the outer surface 521C bulges outward, causing distortion.

[0154] As shown in FIG. 31B, the strain sensor 130 is provided on the outer surface 521C of the main body 521 of the strain element 520 at a position corresponding to the position where the four notches 522A are provided.

[0155] The strain sensor 130 has one or more strain detection elements and detects the strain of the strain generating body 520. For example, each of the strain detection elements is a strain resistance element whose resistance value changes according to the amount of strain. Four strain detection elements may be provided and connected in a bridge shape.

[0156] As an example, wiring board 540 is a wiring board conforming to FR-4 standards, etc. Wiring board 540 is Y-shaped in a plan view, and is housed in the internal space of lower case 510L and upper case 510U.

[0157] If the above-described detection device 500 is provided between the nut 22 and the fastened member 30 through the bolt 21 (see FIG. 10) in the same manner as the detection device 100 of the first embodiment, a strain corresponding to the tightening torque of the nut 22 is generated in the strain element 520. Therefore, the reader device of the detection device 500 can determine the tightening state of the nut 22 based on the voltage value represented by the strain detection signal received from the detection device 500.

[0158] <Effects> The detection device 500 has a main body 521 having a lower end and an upper end, a through hole 523 penetrating the main body 521 in a direction connecting the lower side where the lower end is located and the upper side where the upper end is located, and includes a strain sensor 130 that detects the strain of the strain body 520 due to the fastening axial force applied by the fastening mechanism 20 in the extension direction of the through hole 523, and a strain sensor 130 that accommodates at least a part of the main body 521 of the strain body 520 along the outer surface of the main body 521. The housing 510 includes a case 510, and the flexure body 520 has a flange 522 that protrudes outward from the outer surface of the main body 521 in a plan view when viewed from the opening of the through hole 523, and the flange 522 has a notch 522A that is notched inward at the outer edge of the flange 522 in a plan view when viewed from the opening of the through hole 523, and the case 510 has walls 513L and 513U that face the outer edge of the flange 522, and the walls 513L and 513U have convex portions that protrude inward in a plan view and are accommodated in the notch 522A. Therefore, the notch 522A engages with the convex portion 513LA, and the flexure body 520 can be prevented from rotating relative to the case 510.

[0159] Therefore, it is possible to provide a detection device 500 in which the rotation of the strain body 520 is suppressed.

[0160] Furthermore, the main body 521 has a plurality of flanges 522, which are provided on the outer surface of the main body 521 at intervals along the penetrating direction of the through hole 523, and the strain sensor 130 is provided on the outer surface of the main body 521 in a portion between the plurality of flanges 522. Therefore, on the upper and lower sides of the case 510, the case 510 can stably hold the strain body 520, and the fastening force can be stably detected.

[0161] Also, the detection device 500 further includes a lower O-ring 560 and an upper O-ring 560, and the plurality of flanges 522 have a lower flange 522 arranged on the lower side in the penetrating direction of the through-hole 523 and an upper flange 522 arranged on the upper side in the penetrating direction of the through-hole 523, the lower O-ring 560 is provided in a crushed state between the lower flange 522 and the case 510, and the upper O-ring 560 is provided in a crushed state between the upper flange 522 and the case 510. Therefore, it is possible to prevent water or dust from entering the space surrounded by the case 510 and the strain body 520 from between the case 510 and the strain body 520, and it is possible to provide a highly reliable detection device 500 having a waterproof structure.

[0162] The detector 500 further includes a communication unit that is activated by the power of the signal transmitted from the reader device and emits a signal including data corresponding to the distortion detected by the distortion sensor 130. The data corresponding to the distortion represents the fastening force, for example. Therefore, the reader device can obtain data corresponding to the distortion, and the fastening force can be measured remotely using wireless communication without the need for an operator or the like to directly measure the fastening force. This makes it extremely easy to measure the fastening force. Furthermore, the detector 500 does not require a battery, since it is activated by the power of the signal transmitted from the reader device.

[0163] <Modification of the fifth embodiment> The following description will focus on the differences from the detection device 500 of embodiment 5. The same components as those of the detection device 500 of embodiment 5 are given the same reference numerals, and the description thereof will be omitted. Also, in the drawings, only some of the reference numerals are shown.

[0164] <First Modification of the Fifth Embodiment> 34 is a diagram showing a detection device 500M1 of a first modified example of the fifth embodiment. The detection device 500M1 differs from the case 510 of the detection device 500 of the fifth embodiment in the structure of the case 510M1. The case 510M1 has a housing section 514M1 that is larger on the +Y direction side than the portion that houses the strain body 520 and that houses a battery. The outer shape of the housing section 514M1 of the case 510M1 bulges out to fit the shape of the battery.

[0165] <Second Modification of the Fifth Embodiment> 35A and 35B are diagrams showing a flexure body 520M2 of a second modified example of embodiment 5. Fig. 35B shows a state in which a strain sensor 130 and an O-ring 560 are attached to the flexure body 520M2.

[0166] Body portion 521M2 of strain body 520M2 has lower surface 521A, upper surface 521B, and outer surface 521C, and outer surface 521C is provided with groove 521C1 for fitting and positioning O-ring 560. This makes it easy to position O-ring 560 and prevents it from shifting out of position.

[0167] <Third Modification of the Fifth Embodiment> 36A and 36B are diagrams showing a flexure body 520M3 of a third modified example of embodiment 5. Fig. 36B shows a state in which a strain sensor 130 and an O-ring 560 are attached to the flexure body 520M3.

[0168] The flange 522M3 of the flexure body 520M3 has a smaller radial protrusion amount than the flange 522 of the flexure body 520 of the fifth embodiment. The two O-rings 560 are fitted above and below the two flanges 522M3. The flexure body 520M3 having the flange 522M3 with such a small protrusion amount corresponds to the case where the inner circumferential surface of a case (not shown) is parallel to the outer circumferential surface 521C of the main body 521. The O-ring 560 is crushed between the outer circumferential surface 521C and the inner circumferential surface of the case parallel to the outer circumferential surface 521C.

[0169] <Fourth Modification of the Fifth Embodiment> 37A and 37B are diagrams showing a flexure body 520M4 of a fourth modified example of embodiment 5. Fig. 37B shows a state in which a strain sensor 130 and an O-ring 560 are attached to the flexure body 520M4.

[0170] The flexure body 520M4 does not have a flange, and has a configuration in which notches 521D are provided above and below the outer surface 521C of the main body 521M4. The outer surface 521C has a radial size between the lower and upper sides that is smaller than the radial size of the lower and upper parts. In this way, even if the flexure body 520M4 is used in which the main body 521M4 has notches 521D without a flange, the rotation of the flexure body 520 can be suppressed. Note that, as an example, the O-ring 560 is crushed between the outer surface 521C and the inner peripheral surface of the case parallel to the outer surface 521C, as in the third modified example.

[0171] <Fifth Modification of the Fifth Embodiment> 38A and 38B are diagrams showing a flexure body 520M5 of a fifth modified example of embodiment 5. Fig. 38B shows a state in which a strain sensor 130 and an O-ring 560 are attached to the flexure body 520M5.

[0172] The flexure body 520M5 has a main body 521 configured such that the radial size of the main body 521 of the flexure body 520M4 of the fourth modified example of the fifth embodiment is uniform from the lower surface 521A side to the upper surface 521B side.

[0173] Fig. 38C is an exploded view of a detection device 500M5 including a flexure body 520M5 according to a fifth modified example of embodiment 5. In Fig. 38C, the screw 515 and the O-rings 575A and 575B (see Fig. 31A) are omitted.

[0174] The case 510M5 of the detection device 500M5 has a lower case 510M5L and an upper case 510M5U. The lower case 510M5L has a protrusion 513LA protruding radially inward at an opening 512L at the lower end of the wall 513L, and a protrusion 513LB protruding radially inward at the lower end of the wall 513L. The inner circumferential surface between the lower end and the upper end of the wall 513L is larger in the radial direction in order to fit an O-ring 560, and is recessed radially outward over one circumference of the inner circumferential surface of the wall 513L.

[0175] The upper case 510M5U has a wall 513U. Similar to the wall 513L of the lower case 510M5L, the wall 513U has a convex portion 513UA protruding radially inward at an opening 512U at the upper end of the wall 513U, and a convex portion 513UB protruding radially inward at the lower end of the wall 513U. The inner circumferential surface between the lower end and the upper end of the wall 513U is larger in the radial direction in order to fit an O-ring 560 therein, and is recessed radially outward over one circumference of the inner circumferential surface of the wall 513U.

[0176] 38D and 38E are enlarged views of a portion of the detection device 500M5. As shown in Fig. 38D, the lower O-ring 560 is fitted into a recess between the protrusions 513LA and 513LB of the wall portion 513L of the lower case 510M5L. This is the same on the upper case 510M5U side.

[0177] 38E, the lower cutout 521D of the flexure body 520M5 engages with the convex portion 513LA of the wall portion 513L of the lower case 510M5L, and the convex portion 513LB abuts against the outer surface 521C. Similarly, the upper cutout 521D of the flexure body 520M5 engages with the convex portion 513UA of the wall portion 513U of the upper case 510M5U, and the convex portion 513UB abuts against the outer surface 521C.

[0178] By using such a case 510M5, it is possible to suppress the rotation of the strain body 520M5. The lower O-ring 560 is crushed between the outer surface 521C and the inner circumferential surface of the wall portion 513L of the lower case 510M5L parallel to the outer surface 521C, and the upper O-ring 560 is crushed between the outer surface 521C and the inner circumferential surface of the wall portion 513U of the upper case 510M5U parallel to the outer surface 521C.

[0179] The detection device 500M5 has a main body 521 having a lower end and an upper end, and a through hole 523 penetrating the main body 521 in a direction connecting the lower side where the lower end is located and the upper side where the upper end is located, and includes a strain sensor 130 for detecting the strain of the strain body 520M5 due to the fastening axial force applied by the fastening mechanism 20 in the extension direction of the through hole 523, and the main body of the strain body 520M5. and a case 510M5 that houses at least a portion of 521 along the outer surface of the main body 521, the flexure body 520M5 has a notch 521D that is cut inward from the outer surface of the main body 521 in a plan view, the case 510M5 has walls 513L and 513U that face the outer surface, and the walls 513L and 513U have convex portions 513LA and 513UA that protrude inward in a plan view and are housed in the notch 521D. Therefore, the notch 521D engages with the convex portions 513LA and 513UA, and the flexure body 520M5 can be prevented from rotating relative to the case 510M5.

[0180] Therefore, it is possible to provide a detection device 500M5 in which the rotation of the strain body 520M5 is suppressed.

[0181] <Sixth Modification of the Fifth Embodiment> 39A and 39B are diagrams showing a flexure body 520M6 of a sixth modified example of embodiment 5. Fig. 39B shows a state in which a strain sensor 130 and an O-ring 560 are attached to the flexure body 520M6.

[0182] The flange 522M6 of the flexure body 520M6 has a configuration in which a recess 522B for fitting an O-ring 560 is provided in the flange 522M3 of the third modified example of the fifth embodiment. FIGS. 39A and 39B show the recess 522B of the upper flange 522M6. The recess 522B of the upper flange 522M6 is recessed downward from the upper surface side of the upper flange 522M6 along the outer surface 521C. Such a recess 522B is provided around one circumference of the outer surface 521C. The size of the recess 522B is adjusted to fit the O-ring 560.

[0183] The lower flange 522M6 is also provided with a recess similar to the recess 522B of the upper flange 522M6, and the recess of the lower flange 522M6 is recessed upward from the lower surface side of the lower flange 522M6 along the outer surface 521C.

[0184] By using such a flexure body 520M6, the positioning of the O-ring 560 becomes easy, and positional deviation can be suppressed. Rotation of the flexure body 520M6 can also be suppressed. The lower O-ring 560 is crushed in the vertical direction between the inner surface parallel to the XY plane of the lower case 510L and the lower flange 522. The upper O-ring 560 is crushed in the vertical direction between the inner surface parallel to the XY plane of the upper case 510U and the upper flange 522.

[0185] The above describes an exemplary embodiment of a detection device according to the present disclosure. However, the present disclosure is not limited to the specifically disclosed embodiment, and various modifications and variations are possible without departing from the scope of the claims.

[0186] This international application claims priority to Japanese patent application No. 2022-057382, filed on March 30, 2022, the entire contents of which are incorporated herein by reference. [Explanation of symbols]

[0187] 20 Fastening mechanism 21 Volts 21A Bolt shaft 22 Nut 30 Parts to be fastened 100, 100A, 100B Detector 110 cases 110L lower case 110U Upper case (example of the second wall) 111 Bottom plate portion (an example of a first wall portion) 111A Engagement part 111L Bottom surface (example of the first surface) 111U Top surface (example of the second surface) 112L Opening (example of the first opening) 112U Opening (example of the second opening) 113L Rib (an example of an opposing wall) 113LA Recess 113LB Cutout 113LD convex part 120, 120B, 120C, 120D, 120E strain body 121 Main body 121A Bottom surface (example of the first end surface) 121B Top surface (an example of the second end surface) 121C Outer surface (example of the first outer surface) 122, 122C convex part 122D, 122E recess 123 Through hole 130 Strain Sensor 140, 140A Wiring board 145A signal line 150 Sealing resin (an example of a filling material) 200 Detection Device 220 Strain body 221 Main body 222 Convex 223 Through hole 224 Base 224A Bottom surface (example of the third end surface) 224B Top surface (example of the second end surface) 224C Outer surface (an example of the second outer surface) 225 Extension 225C Outer surface (example of the first outer surface) 226 Enclosure wall 226A Bottom surface (example of the first end surface) 320 Strain body 321 Main body 321A Bottom surface (example of the first end surface) 321B Top surface (example of the second end surface) 321C Outer surface (example of the first outer surface) 322 Convex 323 Through hole 324A First recess 324B Second recess 420 Strain body 421 Main body 421A Bottom side 421B Top 421C External surface 421D Recess 422 Convex 423 Through hole 460 O-ring 500, 500M1, 500M5 Detector 510, 510M1, 510M5 Cases 510L, 510M5L lower case 510U, 510M5U upper case 511 Bottom plate part 511L Bottom 511S side wall 511U top side 512L opening 512U opening 513L wall section 513LA Convex 513LB Convex 513U wall 513UA Convex 513UB Convex part 514M1 Storage unit 515 Screw 520, 520M2, 520M3, 520M4, 520M5, 520M6 strain body 521 Main body 521A Bottom side 521B Top 521C External surface 521C1 groove 521D Notch 521M2 Main body 521M4 Main body 522, 522M3, 522M6 flanges 522A Notch 522B Recess 523 Through hole 540 Wiring Board 560 O-ring 575A O-ring 575B O-ring

Claims

1. a strain generating body having a main body having a first end and a second end, and a through hole passing through the main body in a direction connecting a first side on which the first end is located and a second side on which the second end is located, the through hole being adapted for receiving a bolt portion of a fastening mechanism; a strain sensor that detects a strain of the strain generating body due to a fastening axial force applied in an extending direction of the through hole by the fastening mechanism; a case that accommodates at least a portion of the main body of the strain generating body along a first outer surface of the main body; Including, the strain generating body has at least one convex portion provided on the first outer surface in a circumferential direction surrounding the through hole, the convex portion protruding outward in a plan view beyond the first outer surface, The case has an opposing wall portion facing the first outer surface, The opposing wall portion is recessed outward in a plan view and has a recess that accommodates the protrusion.

2. the case has a first wall portion having a first surface located on the first side, a first opening portion provided in the first wall portion, a second wall portion having a second surface located on the second side, and a second opening portion provided in the second wall portion, the first opening, the opposing wall, and the second opening form a housing portion that houses at least a portion of the main body of the strain body, a first end surface of the first end of the strain generating body is exposed through the first opening and protrudes toward the first side beyond the first surface in an extension direction of the through hole, The detection device according to claim 1 , wherein a second end surface of the second end of the strain generating body is exposed from the second opening and protrudes further toward the second side than the second surface in the extending direction of the through hole.

3. 3. The detection device according to claim 1, wherein a first end surface of the first end portion of the strain generating element and a second end surface of the second end portion of the strain generating element are flat surfaces.

4. The main body portion is a base having a third end on the first side and the second end on the second side, the base surrounding the through hole; An extension portion extending outward in a plan view from a side portion of the base portion; a surrounding wall portion that protrudes from the first side portion of the extension portion to the first side in the extension direction of the through hole and surrounds the second outer surface of the base portion with a gap therebetween; and a first end surface of the first end portion is an end surface on the first side of the surrounding wall portion and protrudes toward the first side more than a third end surface of the third end portion in an extension direction of the through hole; The detection device according to claim 1 , wherein the first outer surface is an outer surface of the extension portion.

5. The main body portion is a plurality of first recesses provided in the first end portion along a periphery of the through hole and recessed toward the second side in an extension direction of the through hole relative to a first end face of the first end portion; a plurality of second recesses provided in the second end portion along a periphery of the through hole and recessed toward the first side in an extension direction of the through hole with respect to a second end face of the second end portion; having The detection device according to claim 1 , wherein the plurality of first recesses and the plurality of second recesses are alternately arranged along a periphery of the through hole.

6. The detection device according to claim 5 , wherein the plurality of first recesses and the plurality of second recesses are arranged to have an overlapping section in a direction surrounding the through hole.

7. a strain generating body having a main body having a first end and a second end, and a through hole passing through the main body in a direction connecting a first side on which the first end is located and a second side on which the second end is located, the through hole being adapted for receiving a bolt portion of a fastening mechanism; a strain sensor that detects a strain of the strain generating body due to a fastening axial force applied in an extending direction of the through hole by the fastening mechanism; a case that accommodates at least a portion of the main body of the strain generating body along a first outer surface of the main body; Including, the strain generating body has at least one recess provided on the first outer surface in a circumferential direction surrounding the through hole, the recess being recessed inwardly from the first outer surface in a plan view, The case has an opposing wall portion facing the first outer surface, The opposing wall portion has a convex portion that protrudes outward in a plan view and is received in the concave portion.

8. a first end surface of the first end portion abuts against either a nut of the fastening mechanism or a fastened member fastened by the fastening mechanism; The detection device according to claim 1 , wherein a second end surface of the second end portion abuts against the other of a nut of the fastening mechanism and a fastened member fastened by the fastening mechanism.

9. 2. The detection device of claim 1, wherein the convex portion is located on the second side of a first end face of the first end and on the first side of a second end face of the second end in an extension direction of the through hole, and a step is provided between the convex portion and the first end face, and a step is provided between the convex portion and the second end face.

10. The detection device according to claim 9 , wherein the case further has an engagement portion that overlaps with the convex portion in a planar view, protrudes toward the first outer surface side beyond the opposing wall portion, and engages with a portion of the convex portion on the first end side.

11. A detection device as described in claim 7, wherein the recess is recessed toward the second side relative to a first end face of the first end in the extension direction of the through hole, and there is a step between the recess and the first end face, or the recess is recessed toward the first side relative to a second end face of the second end in the extension direction of the through hole, and there is a step between the recess and the second end face.

12. The detection device according to claim 1 , wherein the case further includes a notch or hole provided in a part of the opposing wall and through which a signal line connected to the strain sensor passes.

13. The detection device according to claim 1 , further comprising a filler material filled between the first outer surface of the strain generating body and the opposing wall portion of the case.

14. a strain generating body having a main body having a first end and a second end, and a through hole passing through the main body in a direction connecting a first side on which the first end is located and a second side on which the second end is located, the through hole being adapted for receiving a bolt portion of a fastening mechanism; a strain sensor that detects a strain of the strain generating body due to a fastening axial force applied in an extending direction of the through hole by the fastening mechanism; a case that accommodates at least a portion of the main body of the strain generating body along an outer surface of the main body; Including, the strain generating body has a flange that protrudes outward from the outer surface of the main body in a plan view of the opening of the through hole, the flange has at least one notch provided in an outer edge portion of the flange in a circumferential direction surrounding the through hole, the notch being cut inward from the outer edge portion of the flange in a plan view, the case has an opposing wall portion facing the outer edge portion of the flange, The opposing wall portion has a protrusion that protrudes inward in a plan view and is received in the cutout portion.

15. The body portion has a plurality of the flanges, The plurality of flanges are provided on the outer surface of the main body portion and spaced apart from each other along a penetration direction of the through hole, The detection device according to claim 14 , wherein the strain sensor is provided on the outer surface of the main body in a portion between the plurality of flanges.

16. A first O-ring; A second O-ring and Further comprising: The plurality of flanges include a first flange disposed on a first side in a penetration direction of the through hole and a second flange disposed on a second side in the penetration direction of the through hole, the first O-ring is disposed in a crushed state between the first flange and the case, The detection device according to claim 15 , wherein the second O-ring is disposed in a crushed state between the second flange and the case.

17. a strain generating body having a main body having a first end and a second end, and a through hole passing through the main body in a direction connecting a first side on which the first end is located and a second side on which the second end is located, the through hole being adapted for receiving a bolt portion of a fastening mechanism; a strain sensor that detects a strain of the strain generating body due to a fastening axial force applied in an extending direction of the through hole by the fastening mechanism; a case that accommodates at least a portion of the main body of the strain generating body along an outer surface of the main body; Including, the strain generating body has at least one notch provided on the outer surface in a circumferential direction surrounding the through hole, the notch being cut inward from the outer surface in a plan view, The case has an opposing wall portion facing the outer surface, The opposing wall portion has a protrusion that protrudes inward in a plan view and is received in the cutout portion.

18. The detection device according to claim 1 , further comprising a communication unit that is activated by the power of a signal transmitted from a reader device and emits a signal including data corresponding to the distortion detected by the distortion sensor.

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