Sensor module

Abstract

A sensor module (1) comprises: a base body (90) having an annular shape surrounding a central axis (A); an acceleration sensor (20) placed on the base body (90); a wireless communication module (30) placed on the base body (90) and electrically connected to the acceleration sensor (20); and a secondary battery (60) placed in the base body (90) and supplying power to the acceleration sensor (20) and the wireless communication module (30). The base body (90) includes: a body part (70) having an inner peripheral surface (74) along a cylindrical surface surrounding the central axis (A); and an adjustment member (80) installed in the body part (70) for adjusting the diameter of the inner peripheral surface (70).

Description

Sensor Module

[0001] The present disclosure relates to a sensor module.

[0002] In order to monitor the operating state of a rotating body, a sensor is sometimes installed on the rotating body. For example, a technique is known in which a sensor, a memory, a communication means, a battery, and the like are embedded in a polishing apparatus, which is a rotating body, to monitor the state of the polishing apparatus (see, for example, Japanese Patent Laid-Open No. 2011-194506 (Patent Document 1)).

[0003] JP 2011-194506 A

[0004] In a configuration such as that described in Patent Document 1, sensors, batteries, etc. are embedded in a portion of the equipment. Therefore, it is necessary to modify a portion of the existing equipment to one with embedded sensors, etc. This can result in problems in terms of cost. Furthermore, when sensors, batteries, etc. are embedded in a portion of a rotating body, the space required for embedding the sensors, batteries, etc. is formed, which may reduce the rigidity of the rotating body. The present disclosure addresses these problems, and one of its objectives is to provide a sensor module that can be installed on a rotating body while keeping costs down and that minimizes the impact on the rigidity of the rotating body.

[0005] A sensor module according to the present disclosure includes a base body having an annular shape surrounding a central axis, a sensor mounted on the base body, a wireless communication module mounted on the base body and electrically connected to the sensor, and a secondary battery mounted on the base body and supplying power to the sensor and the wireless communication module. The base body includes a main body having an inner circumferential surface along a cylindrical surface surrounding the central axis, and an adjustment member mounted on the main body for adjusting the diameter of the inner circumferential surface.

[0006] According to the above sensor module, it is possible to provide a sensor module that can be installed on a rotating body while keeping costs down and that has a reduced effect on the rigidity of the rotating body.

[0007] FIG. 1 is a schematic perspective view showing the structure of a sensor module according to a first embodiment. FIG. 2 is a schematic perspective view showing the structure of a substrate module. FIG. 3 is a schematic perspective view showing the structure of a substrate module. FIG. 4 is a schematic plan view showing the structure of a substrate module. FIG. 5 is a schematic plan view showing the structure of a substrate module. FIG. 6 is a schematic perspective view showing the structure of a lithium ion secondary battery. FIG. 7 is a schematic cross-sectional view showing the structure of a lithium ion secondary battery. FIG. 8 is a schematic cross-sectional view showing the structure of a lithium ion secondary battery. FIG. 9 is a schematic perspective view showing a state in which the sensor module according to the first embodiment is installed on a rotating body. FIG. 10 is a schematic cross-sectional view showing the structure of the sensor module according to the first embodiment installed on a rotating body. FIG. 11 is a schematic perspective view showing the structure of a sensor module according to a second embodiment. FIG. 12 is a schematic cross-sectional view showing the structure of the sensor module according to the second embodiment. FIG. 13 is a schematic cross-sectional view showing the structure of a sensor module according to a third embodiment.

[0008] [Summary of the embodiment] First, embodiments of the present disclosure will be listed and described. The sensor module of the present disclosure includes a base body having an annular shape surrounding a central axis, a sensor mounted on the base body, a wireless communication module mounted on the base body and electrically connected to the sensor, and a secondary battery mounted on the base body and supplying power to the sensor and the wireless communication module. The base body includes a main body having an inner circumferential surface along a cylindrical surface surrounding the central axis, and an adjustment member mounted on the main body for adjusting the diameter of the inner circumferential surface.

[0009] In the sensor module of the present disclosure, the main body of the base body, on which the sensor, wireless communication module, and secondary battery are mounted, has an inner circumferential surface that conforms to a cylindrical surface surrounding the central axis. The diameter of the inner circumferential surface of the main body is adjustable using an adjustment member. Therefore, the sensor module can be mounted on a rotating body by first installing the main body so that the inner circumferential surface of the main body surrounds the outer circumferential surface of the rotating body, and then adjusting the diameter of the inner circumferential surface using the adjustment member so that the inner circumferential surface of the main body fastens against the outer circumferential surface of the rotating body. This does not require modifying a portion of existing equipment to one with an embedded sensor or the like. This reduces costs. Furthermore, since there is no need to embed a sensor or the like in a portion of the existing rotating body, a decrease in the rigidity of the rotating body can be suppressed. Thus, the sensor module of the present disclosure can be mounted on a rotating body while keeping costs down and minimizing the impact on the rigidity of the rotating body.

[0010] In the sensor module, the main body may be made of resin, which has a lower specific gravity than metal or the like, making it possible to reduce the effect of the sensor module installation on the rotation of the rotor.

[0011] The sensor module may further include a weight attached to the base body to move the center of gravity of the sensor module closer to the central axis, thereby preventing the center of gravity from shifting from the central axis (axis of rotation) of the rotating body on which the sensor module is attached.

[0012] In the sensor module, the weight may be mounted on the base body in a state in which the distance from the central axis is adjustable. This configuration facilitates more precise adjustment of the center of gravity of the rotating body on which the sensor module is mounted.

[0013] In the sensor module, the main body may have a removed portion formed therein to move the center of gravity of the sensor module closer to the central axis. This configuration makes it possible to prevent the center of gravity from shifting from the central axis (rotation axis) of the rotating body on which the sensor module is installed.

[0014] In the sensor module, the wireless communication module may include an antenna that transmits a signal to the outside. The distance between the antenna and the central axis may be greater than the distance between the sensor and the central axis. By bringing the sensor and the central axis closer together, the distance between the sensor and the rotating body can be reduced when the sensor module is installed on the rotating body. This allows the sensor to detect the state of the rotating body more accurately. Furthermore, by increasing the distance between the antenna and the central axis, the distance between the antenna and the rotating body can be increased when the sensor module is installed on the rotating body. This reduces the risk that the rotating body will interfere with signal transmission from the antenna.

[0015] In the sensor module, the secondary battery may include a separator, a positive electrode layer and a negative electrode layer sandwiching the separator, an electrolyte impregnated in the separator, the positive electrode layer, and the negative electrode layer, and an exterior material accommodating the separator, the positive electrode layer, the negative electrode layer, and the electrolyte. At least one of the positive electrode layer and the negative electrode layer may be a sintered electrode layer that is an electrode layer made of a sintered body.

[0016] When a sensor module including a secondary battery is installed on a rotating body, centrifugal force acts on the secondary battery as the rotating body rotates. This centrifugal force causes the electrolyte contained in the secondary battery to become unevenly distributed, resulting in a state in which the electrolyte is not impregnated in part or all of the positive electrode layer and negative electrode layer. As a result, the parts of the positive electrode layer and negative electrode layer that are not impregnated with the electrolyte do not function, and the performance of the secondary battery deteriorates.

[0017] In contrast, as described above, a sintered electrode layer is used for at least one of the positive and negative electrode layers. Because the sintered body has a structure in which raw material particles are joined by necks, the pores within the sintered body have a complex, labyrinth-like shape, which provides a high level of electrolyte retention. As a result, even when the sensor module is mounted on a rotating body and centrifugal force acts on the secondary battery, the electrolyte is retained in the sintered electrode layer, preventing a deterioration in the secondary battery's performance.

[0018] [Specific Example of the Embodiment] Next, specific examples of the sensor module of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference characters, and description thereof will not be repeated.

[0019] (Embodiment 1) Fig. 1 is a schematic perspective view showing the structure of a sensor module of embodiment 1. Figs. 2 and 3 are schematic perspective views showing the structure of a substrate module. Figs. 2 and 3 are perspective views seen from different viewpoints. Figs. 4 and 5 are schematic plan views showing the structure of the substrate module. Figs. 4 and 5 are plan views seen from opposite directions in the thickness direction of the substrate module.

[0020] Referring to FIG. 1 , the sensor module 1 of this embodiment includes a base body 90 having an annular shape surrounding a central axis A, and a substrate module 10 mounted on the base body 90. Referring to FIGS. 2 to 5 , the substrate module 10 includes a wiring board 11, an acceleration sensor 20, a wireless communication module 30, a wireless charging module 40, a plurality of electronic components 51, and a lithium-ion secondary battery 60. The wireless communication module 30 includes an antenna 31. That is, the acceleration sensor 20, the wireless charging module 40, and the lithium-ion secondary battery 60, which are components of the substrate module 10, are mounted on the base body 90. The base body 90 includes a main body 70 having an inner circumferential surface 74 that conforms to a cylindrical surface surrounding the central axis A, and an adjustment member 80 mounted on the main body 70 and that adjusts the diameter of the inner circumferential surface 74.

[0021] <Main Body> The main body 70 is made of, for example, a resin. Examples of resins that can be used to form the main body 70 include polyethylene, polybutylene terephthalate, and polylactic acid. The main body 70 has a hollow cylindrical (annular) shape with a cylindrical through-hole whose central axis coincides with the central axis A, with a portion of the circumferential surface removed. More specifically, the main body 70 includes an outer peripheral surface 73, an inner peripheral surface 74, a first end face 71, a second end face 72, a first opposing surface 75, and a second opposing surface 76. The outer peripheral surface 73 is a surface that conforms to a cylindrical surface having a central axis that coincides with the central axis A. The inner peripheral surface 74 is a surface that conforms to a cylindrical surface having a central axis that coincides with the central axis A and has a smaller diameter than the outer peripheral surface 73. The first end face 71 is a surface that conforms to a plane that intersects (is perpendicular to) the central axis A and connects the outer peripheral surface 73 and the inner peripheral surface 74. The second end surface 72 is a surface along a plane intersecting (orthogonal to) the central axis A, is positioned apart from the first end surface 71 in the direction along the central axis A, and connects the outer peripheral surface 73 and the inner peripheral surface 74. The first opposing surface 75 is a surface that defines a notch portion 70A that penetrates radially through the main body portion 70 from the inner peripheral surface 74 to the outer peripheral surface 73 and axially through the main body portion 70 from the first end surface 71 to the second end surface 72, and is connected to the outer peripheral surface 73, the inner peripheral surface 74, the first end surface 71, and the second end surface 72. The second opposing surface 76 is a surface that defines the notch portion 70A, and is connected to the outer peripheral surface 73, the inner peripheral surface 74, the first end surface 71, and the second end surface 72, and faces the first opposing surface 75.

[0022] A first recess 74A is formed in the inner circumferential surface 74 and recessed in the radial direction of the main body 70. The first recess 74A is defined by a bottom surface 74B (see FIG. 10 described below), a pair of first side surfaces 74C that rise from the outer edge of the bottom surface 74B and face each other in the direction along the central axis A, and a pair of second side surfaces 74D that rise from the outer edge of the bottom surface 74B and face each other in the direction along the radial direction of the inner circumferential surface 74. The bottom surface 74B is a flat surface.

[0023] A pair of recesses 73A whose depth increases circumferentially toward the cutout 70A are formed in the outer peripheral surface 73. Each of the pair of recesses 73A is defined by a bottom surface 73B, a pair of first side surfaces 73C that rise from the outer edge of the bottom surface 73B and face each other in the direction along the central axis A, and a second side surface 73D that rises from the end of the bottom surface 73B on the cutout 70A side. The pair of second side surfaces 73D that define the pair of recesses 73A are parallel to each other.

[0024] <Adjusting Member> Referring to FIG. 1 , the adjusting member 80 includes a bolt 81 and a nut 82 threaded onto the bolt 81. In the present embodiment, the adjusting member 80 includes a pair of bolts 81 and a pair of nuts 82 threaded onto each bolt 81. The adjusting member of the present disclosure may include one bolt 81 and one nut 82 threaded onto the bolt 81, or may include three or more bolts 81 and three or more nuts 82 threaded onto each bolt 81. The bolt 81 includes a head 81A and a shaft 81B connected to the head 81A. The head 81A is disposed in one of the pair of recesses 73A. The nut 82 is disposed in the other of the pair of recesses 73A. The shaft portion 81B penetrates the main body 70 from the second side surface 73D that defines one recess 73A to the first opposing surface 75, and from the second opposing surface 76 to the second side surface 73D that defines the other recess 73A, reaching the inside of the other recess 73A. A helical thread is formed on the outer peripheral surface of the shaft portion 81B, and a thread groove that corresponds to the thread of the shaft portion 81B is formed on the inner peripheral surface of the nut 82. The nut 82 is threadedly engaged with the shaft portion 81B.

[0025] <Substrate Module> The wiring substrate 11 includes a base substrate made of an insulating material such as resin, and wiring made of a conductive material such as copper arranged on at least one of the surface and the interior of the base substrate. The wiring substrate 11 is, for example, a printed wiring board. The wiring substrate 11 includes a first mounting surface 11A and a second mounting surface 11B located on the opposite side of the first mounting surface 11A in the thickness direction.

[0026] The acceleration sensor 20 is disposed on the first mounting surface 11A of the wiring board 11. The acceleration sensor 20 is electrically connected to the wiring that constitutes the wiring board 11. The acceleration sensor 20 detects acceleration such as vibration and outputs a signal containing information about the detected acceleration. In this embodiment, only one acceleration sensor 20 is disposed on the first mounting surface 11A, but multiple acceleration sensors may be disposed. Furthermore, instead of or in addition to the acceleration sensor 20, another sensor, such as a temperature sensor, may be disposed on the first mounting surface 11A.

[0027] The wireless communication module 30 is disposed on the first mounting surface 11A of the wiring board 11. The wireless communication module 30 is electrically connected to the wiring that constitutes the wiring board 11. The wireless communication module 30 is electrically connected to the acceleration sensor 20 via the wiring. The wireless communication module 30 includes an antenna 31. The wireless communication module 30 transmits a signal including information such as acceleration detected by a sensor such as the acceleration sensor 20 from the antenna 31 to the outside.

[0028] The wireless charging module 40 is disposed on the first mounting surface 11A of the wiring board 11. The wireless charging module 40 is electrically connected to the wiring that constitutes the wiring board 11. The wireless charging module 40 includes a power receiving coil (not shown). A magnetic field generated by a current flowing through an external power transmitting coil causes a current to flow through the power receiving coil, thereby charging the lithium ion secondary battery 60, which will be described later. Note that the lithium ion secondary battery 60 may be charged, for example, by a microwave method in which a current flowing through an external power transmitting antenna is converted into electromagnetic waves and received by a power receiving antenna.

[0029] The electronic components 51 may be, for example, passive elements, semiconductor elements, etc. Examples of semiconductor elements include transistors, diodes, etc. The electronic components 51 are electrically connected to the wiring that constitutes the wiring board 11.

[0030] The lithium-ion secondary battery 60 is disposed on the second mounting surface 11B of the wiring board 11. The lithium-ion secondary battery 60 is electrically connected to the wiring constituting the wiring board 11. The lithium-ion secondary battery 60 is electrically connected to the wireless charging module 40 via the wiring. The lithium-ion secondary battery 60 is charged by current flowing through the power receiving coil as a result of current flowing through the external power transmitting coil. The lithium-ion secondary battery 60 is electrically connected to the acceleration sensor 20, the wireless communication module 30, and multiple electronic components 51 via the wiring. As a result, the lithium-ion secondary battery 60 supplies power to the acceleration sensor 20, the wireless communication module 30, and the like. Referring to FIG. 4 , the antenna 31 and the lithium-ion secondary battery 60 are arranged so as not to overlap each other when viewed in a direction perpendicular to the first mounting surface 11A. The substrate module 10 is housed in the first recess 74A so that the lithium-ion secondary battery 60 faces the bottom surface 74B.

[0031] <Secondary Battery> Next, the structure of the lithium ion secondary battery 60 will be described. Fig. 6 is a schematic perspective view showing the structure of a lithium ion secondary battery. Figs. 7 and 8 are schematic cross-sectional views showing the structure of a lithium ion secondary battery. Fig. 7 shows a cross section taken along line VII-VII in Fig. 6. Fig. 8 shows a cross section taken along line VIII-VIII in Fig. 6.

[0032] 6 to 8 , a lithium-ion secondary battery 60 according to the present embodiment includes a pair of exterior films 600, a battery body 620, a positive electrode tab terminal 631, and a negative electrode tab terminal 632. Each exterior film 600 has the same rectangular shape when viewed in the thickness direction. In the pair of exterior films 600, which are exterior materials, first outer edges 601 corresponding to the first short sides of the rectangle, second outer edges 602 corresponding to the first long sides, third outer edges 603 corresponding to the second short sides, and fourth outer edges 604 corresponding to the second long sides are bonded to each other. More specifically, the first outer edges 601 are bonded to each other over the entire area except for portions facing each other across the positive electrode tab terminal 631 and the negative electrode tab terminal 632 (see FIG. 8 ). The second outer edges 602, the third outer edges 603, and the fourth outer edges 604 are bonded to each other over the entire circumferential area. In this embodiment, the outer edges 601 to 604 are joined by fusion. The joining can be achieved by heat fusion. That is, in the pair of exterior films 600, the outer edges 601 to 604 are joined (fused) to each other in a stacked state. Referring to FIG. 7 , the pair of exterior films 600 each include an inner surface 600A that is a surface facing each other, and an outer surface 600B that is a main surface opposite the inner surface 600A. An internal space 600C is formed between the facing inner surfaces 600A of the pair of exterior films 600.

[0033] 7 , the internal space 600C accommodates a battery body 620. The battery body 620 includes a separator film 621 as a separator, a positive electrode layer 622, a negative electrode layer 623, a positive electrode current collector foil 624, a negative electrode current collector foil 625, and an electrolyte 626.

[0034] The separator film 621 is a resin film. Examples of resins that can be used to form the separator film 621 include polyolefin, polyimide, polyester (e.g., polyethylene terephthalate (PET)), and cellulose.

[0035] The positive electrode layer 622 is laminated on a first main surface 621A, which is one of the main surfaces of the separator film 621. The positive electrode layer 622 of this embodiment is a plate-shaped sintered body of lithium composite oxide. That is, the positive electrode layer 622 of this embodiment is a sintered electrode layer, which is an electrode layer made of a sintered body. The positive electrode layer 622 does not contain a binder. The lithium composite oxide is a sintered electrode layer made of Li ｘ MO ２ (0.05<x<1.10, M is at least one transition metal, and M typically includes one or more of Co (cobalt), Ni (nickel), and Mn (manganese). The average pore size of the sintered body constituting the positive electrode layer 622 is, for example, 0.2 μm or more and 5.0 μm or less.

[0036] The negative electrode layer 623 is laminated on a second main surface 621B of the separator film 621, which is located on the opposite side in the thickness direction to the first main surface 621A. The negative electrode layer 623 includes carbon such as graphite as a negative electrode active material and a binder such as styrene butadiene rubber (SBR) or polyvinylidene fluoride (PVDF). In the present embodiment, only one separator film 621, one positive electrode layer 622, and one negative electrode layer 623 are housed in the exterior film 600 (in the internal space 600C) as an exterior material.

[0037] The positive electrode current collector foil 624 is laminated on the side of the positive electrode layer 622 opposite to the separator film 621. The positive electrode current collector foil 624 is a foil made of a metal that is an electrical conductor. For example, Al (aluminum) can be used as the metal constituting the positive electrode current collector foil 624. The positive electrode current collector foil 624 is disposed between the positive electrode layer 622 and the inner surface 600A of the exterior film 600. The positive electrode current collector foil 624 is disposed along the inner surface 600A of the exterior film 600.

[0038] The negative electrode current collector foil 625 is laminated on the negative electrode layer 623 on the side opposite to the separator film 621. The negative electrode current collector foil 625 is a foil made of a metal that is an electrical conductor. Examples of metals that can be used to form the negative electrode current collector foil 625 include Cu (copper) and Al. The negative electrode current collector foil 625 is disposed between the negative electrode layer 623 and the inner surface 600A of the exterior film 600. The negative electrode current collector foil 625 is disposed along the inner surface 600A of the exterior film 600.

[0039] The electrolyte 626 is impregnated into the separator film 621, the positive electrode layer 622, and the negative electrode layer 623. The electrolyte 626 is a solution of a lithium salt (e.g., LiPF ) in an organic solvent (e.g., a mixed solvent of ethylene carbonate (EC) and methyl ethyl carbonate (MEC), a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC), or a mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC)). ６ ) A solution in which a salt is dissolved can be used.

[0040] The positive electrode tab terminal 631 is connected to the battery body 620 between the pair of exterior films 600 and extends to the outside. The negative electrode tab terminal 632 is connected to the battery body 620 between the pair of exterior films 600 and extends to the outside. The positive electrode tab terminal 631 is connected to the positive electrode current collector foil 624. The negative electrode tab terminal 632 is connected to the negative electrode current collector foil 625. The positive electrode tab terminal 631 and the negative electrode tab terminal 632 have a strip-like shape. Referring to FIG. 8 , the positive electrode tab terminal 631 includes a conductive main body 631A and a resin protective layer 631B arranged to cover the surface of the main body 631A. The negative electrode tab terminal 632 includes a conductive main body 632A and a resin protective layer 632B arranged to cover the surface of the main body 632A. The conductors constituting the main bodies 631A and 632A may be metals such as aluminum (Al) and nickel (Ni).

[0041] In the sensor module 1, both the positive electrode layer 622 and the negative electrode layer 623 may be sintered electrode layers. Specifically, for example, the negative electrode layer 623 may be made of lithium titanate Li ４Ti ５ O １２ (hereinafter referred to as LTO) or niobium titanium composite oxide Nb ２ TiO ７ A titanium-containing sintered body containing the above-mentioned titanium compound can be used. This configuration makes it possible to suppress deterioration in the characteristics of the lithium-ion secondary battery 60 due to the action of centrifugal force, regardless of the installation mode of the sensor module 1. Furthermore, contrary to the above embodiment, the negative electrode layer 623 does not have to be a sintered electrode layer, and the positive electrode layer 622 does not have to be a sintered electrode layer.

[0042] <Installation on a Rotating Body> Next, an installation mode of the sensor module 1 according to the first embodiment on a rotating body will be described. Fig. 9 is a schematic perspective view showing a state in which the sensor module according to the first embodiment is installed on a rotating body. Fig. 10 is a schematic cross-sectional view showing the structure of the sensor module according to the first embodiment when installed on a rotating body.

[0043] 9 , the sensor module 1 of the first embodiment can be installed so as to surround the outer peripheral surface 101 of the rotating body 100. Specifically, with reference to FIGS. 9 and 10 , first, with the adjustment member 80 not fastened or removed, the base body 90 (main body 70) constituting the sensor module 1 is positioned so that the inner peripheral surface 74 of the main body 70 of the base body 90 surrounds the outer peripheral surface 101 of the rotating body 100. Next, (after the bolt 81 and nut 82 are attached) the nut 82 is tightened. This reduces the diameter of the inner peripheral surface 74 of the main body 70. As a result, the sensor module 1 is installed on the rotating body 100 so that the main body 70 tightens the rotating body 100 with the inner peripheral surface 74 and the outer peripheral surface 101 in contact with each other. The sensor module 1 is installed on the rotating body 100 so that the central axis A of the sensor module 1 coincides with the central axis B of the rotating body.

[0044] In the sensor module 1 of this embodiment, the diameter of the inner circumferential surface 74 of the main body 70 is adjustable by the adjustment member 80. Therefore, by adjusting the diameter of the inner circumferential surface 74 using the adjustment member 80 as described above, the sensor module 1 can be installed on the rotating body 100. In this case, there is no need to modify a portion of the existing equipment to one with an embedded sensor or the like. That is, the sensor module 1 can be installed as an additional device without modifying the existing equipment itself. This reduces costs. Furthermore, because there is no need to embed a sensor or the like in a portion of the existing rotating body 100, a decrease in the rigidity of the rotating body 100 can be reduced. Thus, the sensor module 1 of this embodiment is a sensor module that can be installed on the rotating body 100 at low cost and that can reduce the impact on the rigidity of the rotating body 100.

[0045] 10 , in the sensor module 1 of this embodiment, two threaded holes 73H are formed in the outer peripheral surface 73 of the main body 70. The sensor module 1 is provided with an adjustment screw 91 as a first weight that can be screwed into each of the threaded holes 73H. The adjustment screw 91 is a weight that is installed in the main body 70 of the base body 90 and moves the center of gravity of the sensor module 1 closer to the central axis A. The distance between the adjustment screw 91 and the central axis A can be changed by changing the depth to which the adjustment screw 91 is screwed into the threaded hole 73H. This makes it possible to suppress deviation of the center of gravity from the central axis B of the rotating body 100 on which the sensor module 1 is installed.

[0046] As shown in FIG. 10, in the sensor module 1 of this embodiment, the distance d between the antenna 31 and the central axis A is ２ is the distance d between the acceleration sensor 20 and the central axis A １ By bringing the acceleration sensor 20 closer to the central axis A, the distance d between the acceleration sensor 20 and the rotating body 100 is reduced. １ This allows the acceleration sensor to detect the state (for example, vibration) of the rotating body 100 more precisely. ２By increasing the distance between the antenna 31 and the rotating body 100, it is possible to increase the distance between the antenna 31 and the rotating body 100. This reduces the possibility that the rotating body 100 will block the transmission of signals from the antenna 31.

[0047] (Embodiment 2) Next, embodiment 2, which is another embodiment of the present disclosure, will be described. Fig. 11 is a schematic perspective view showing the structure of a sensor module of embodiment 2. Fig. 12 is a schematic cross-sectional view showing the structure of a sensor module of embodiment 2. With reference to Figs. 11 and 12 as well as Figs. 1 and 10, sensor module 1 of embodiment 2 basically has the same configuration as sensor module 1 of embodiment 1 and achieves the same effects. However, sensor module 1 of embodiment 2 differs from embodiment 1 in the following respects.

[0048] 11 and 12 , a pair of notches 70A are formed symmetrically with respect to the central axis A in the main body 70 of the base body 90 constituting the sensor module 1 of the second embodiment. From another perspective, in addition to the one notch 70A formed in the first embodiment, the main body 70 of the second embodiment has another notch 70A formed on the opposite side of the one notch 70A as viewed from the central axis A. That is, the main body 70 is divided into two members. Furthermore, in addition to the pair of recesses 73A of the first embodiment, an additional pair of recesses 73A are formed symmetrically with respect to the central axis A in the outer peripheral surface 73 of the main body 70. A pair of adjustment members 80 are arranged so that a head 81A of a bolt 81 is positioned in one of the additional pair of recesses 73A and a nut 82 is positioned in the other.

[0049] Referring to FIG. 12 , a first recess 74A is formed on the inner circumferential surface 74 of one of the two divided main body portions 70, as in the first embodiment. The first recess 74A accommodates the substrate module 10, as in the first embodiment. A second recess 74E is formed on the inner circumferential surface 74 of the other of the two divided main body portions 70. An adjustment plate 93 serving as a second weight is accommodated within the second recess 74E. The mass of the adjustment plate 93 is not particularly limited, but may be greater than the mass of the adjustment screw 91, for example. This allows the adjustment plate 93 to roughly adjust the center of gravity of the rotating body 100 on which the sensor module 1 is installed, and then fine adjustment can be performed with the adjustment screw 91. Furthermore, because the main body portion 70 is divided into two, the sensor module 1 of this embodiment offers greater flexibility in the shape of the rotating body 100 on which it is installed.

[0050] Third Embodiment Next, a third embodiment, which is yet another embodiment of the present disclosure, will be described. Fig. 13 is a schematic cross-sectional view showing the structure of a sensor module according to the third embodiment. Referring to Figs. 13 and 12, the sensor module 1 according to the third embodiment has basically the same configuration as the sensor module 1 according to the second embodiment, and achieves the same effects. However, the sensor module 1 according to the third embodiment differs from the sensor module 1 according to the second embodiment in the mechanism for suppressing deviation of the center of gravity from the central axis B of the rotating body 100 on which the sensor module 1 is installed.

[0051] 13 and 12 , in the sensor module 1 of the third embodiment, the adjustment screw 91 and adjustment plate 93 of the second embodiment are omitted, and the threaded hole 73H and second recess 74E are also omitted. Meanwhile, a removed portion 74F, which is a region obtained by removing a portion of the main body 70 so as to bring the center of gravity of the sensor module 1 closer to the central axis A, is formed on the inner circumferential surface 74 of the main body 70 of the base body 90 that constitutes the sensor module 1 of the third embodiment. In this way, by adopting a structure in which the removed portion 74F is used instead of the adjustment screw 91 and adjustment plate 93 to bring the center of gravity closer to the central axis A, it is possible to reduce the number of parts and achieve a lighter sensor module 1.

[0052] The configurations described in the first to third embodiments can be implemented in appropriate combinations.

[0053] It should be understood that the embodiments disclosed herein are illustrative in all respects and are not limiting in any respect. The scope of the present disclosure is defined not by the above description but by the scope of the claims, and it is intended to include all modifications within the meaning and scope of the claims.

[0054] 1 Sensor module, 10 Substrate module, 11 Wiring board, 11A First mounting surface, 11B Second mounting surface, 20 Acceleration sensor, 30 Wireless communication module, 31 Antenna, 40 Wireless charging module, 51 Electronic component, 60 Lithium ion secondary battery, 70 Main body, 70A Notched portion, 71 First end surface, 72 Second end surface, 73 Outer peripheral surface, 73A Recess, 73B Bottom surface, 73C First side surface, 73D Second side surface, 73H Screw hole, 74 Inner peripheral surface, 74A First recess, 74B Bottom surface, 74C First side surface, 74D Second side surface, 74E Second recess, 74F Removal portion, 75 First opposing surface, 76 Second opposing surface, 80 Adjustment member, 81 Bolt, 81A Head, 81B Shaft portion, 82 Nut, 90 Base body, 91 Adjusting screw, 93 Adjusting plate, 100 Rotating body, 101 Outer peripheral surface, 600 Exterior film, 600A Inner surface, 600B Outer surface, 600C Internal space, 601 First outer edge, 602 Second outer edge, 603 Third outer edge, 604 Fourth outer edge, 620 Battery body, 621 Separator film, 621A First main surface, 621B Second main surface, 622 Positive electrode layer, 623 Negative electrode layer, 624 Positive electrode current collector foil, 625 Negative electrode current collector foil, 626 Electrolyte, 631 Positive electrode tab terminal, 631A Main body, 631B Protective layer, 632 Negative electrode tab terminal, 632A Main body, 632B Protective layer, A Central axis, d １ , d ２ distance.

Claims

1. A sensor module comprising: a base body having an annular shape surrounding a central axis; a sensor mounted on the base body; a wireless communication module mounted on the base body and electrically connected to the sensor; and a secondary battery mounted on the base body and supplying power to the sensor and the wireless communication module, wherein the base body includes a main body portion having an inner circumferential surface that follows a cylindrical surface surrounding the central axis; and an adjustment member mounted on the main body portion for adjusting the diameter of the inner circumferential surface.

2. The sensor module according to claim 1, wherein the main body is made of resin.

3. The sensor module according to claim 1 or 2, further comprising a weight attached to the base body to bring the center of gravity of the sensor module closer to the central axis.

4. The sensor module according to claim 3, wherein the weight is mounted on the base body in a state where the distance from the central axis is adjustable.

5. A sensor module as described in any one of claims 1 to 4, wherein the main body portion has a removed portion formed therein, which is a region in which a portion of the main body portion has been removed so as to bring the center of gravity of the sensor module closer to the central axis.

6. A sensor module according to any one of claims 1 to 5, wherein the wireless communication module includes an antenna for transmitting signals to the outside, and the distance between the antenna and the central axis is greater than the distance between the sensor and the central axis.

7. A sensor module according to any one of claims 1 to 6, wherein the secondary battery includes a separator, a positive electrode layer and a negative electrode layer sandwiched by the separator, an electrolyte impregnated in the separator, the positive electrode layer, and the negative electrode layer, and an exterior material that houses the separator, the positive electrode layer, the negative electrode layer, and the electrolyte, and at least one of the positive electrode layer and the negative electrode layer is a sintered electrode layer that is an electrode layer made of a sintered body.

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