Endlessly rotating body

Abstract

To provide an endlessly rotating body in which a piezoelectric element is arranged in a disk part, which can be enhanced in efficiency of electric power generation.SOLUTION: A wheel 10 comprises a rim part 11 and a disk part 12 arranged inside a ring of the rim part 11. A piezoelectric element 28 is arranged at a position in the disk part 12 where stress becomes relatively higher during running. This enables electric power to be generated by the wheel 10. The piezoelectric element 28 is arranged at a position in the disk part 12 where stress becomes relatively higher during running, thereby enhancing efficiency of electric power generation.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an infinite rotating body such as a tire wheel. [Background technology]

[0002] There are techniques for arranging piezoelectric elements on tires, wheels, etc. For example, Patent Document 1 describes attaching a piezoelectric sensor to the outer peripheral surface of the rim of a wheel. Patent Document 2 describes providing a coated piezoelectric part on the back surface of the tire's contact area. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-163230 A [Patent Document 2] Patent Publication No. 2022-47625 Summary of the Invention [Problem to be solved by the invention]

[0004] Although Patent Document 1 describes the idea of ​​placing a piezoelectric sensor on the outer peripheral surface of the rim, the outer peripheral surface of the rim of wheels in practical use has a complex shape. Further technical consideration is required to determine the best position for placing the piezoelectric element in accordance with this complex shape of the outer peripheral surface of the rim.

[0005] In Patent Document 2, power is generated according to the distortion caused on the tire's contact surface. As a result, there is a risk that the piezoelectric part arranged on the rear surface of the tire's contact surface may be damaged as the tire is repeatedly deformed. [Means for solving the problem]

[0006] The infinite rotating body for solving the above problems has the following features. [Aspect 1] A rim portion, a disk portion disposed inside the annulus of the rim portion; The disk portion has a piezoelectric element disposed at a position where stress is relatively high during running. Infinite rotating body.

[0007] According to the above-mentioned configuration, power can be generated by the wheel. The piezoelectric element is disposed at a position in the disk portion where the stress is relatively high during running, thereby improving the power generation efficiency.

[0008] [Aspect 2] The disk portion includes a hub attachment portion, a disk flange portion, and a plurality of holes periodically arranged in a circumferential direction between the hub attachment portion and the disk flange portion, and includes an annular protrusion that is continuous or discontinuous in the circumferential direction between the hub attachment portion and the holes, The infinite rotor according to [Aspect 1], wherein the piezoelectric element is disposed at the annular protrusion.

[0009] According to the above configuration, the piezoelectric element is disposed on the annular protrusion where stress is high, thereby making it possible to improve power generation efficiency. [Aspect 3] The disk portion includes a hub attachment portion, a disk flange portion, and a plurality of holes that are periodically arranged in a circumferential direction between the hub attachment portion and the disk flange portion, The position where the piezoelectric element is disposed is between the hole portions and is closer to the hub attachment portion than the disk flange portion.

[0010] According to the above configuration, the piezoelectric element is disposed in the hole where stress is high and at a position closer to the hub attachment portion than to the disk flange portion, thereby making it possible to increase power generation efficiency. [Aspect 4] The infinite rotor according to [Aspect 2] or [Aspect 3], wherein the piezoelectric elements are intermittently arranged at the same period in the circumferential direction.

[0011] According to the above configuration, it is possible to prevent the outputs of adjacent piezoelectric elements from cancelling each other out. [Aspect 5] The infinite rotor according to [Aspect 2] or [Aspect 3], wherein the piezoelectric element is disposed on an inner surface of the disk portion in the vehicle width direction.

[0012] According to the above configuration, it is possible to make the vehicle less visible from the outside in the vehicle width direction. [Aspect 6] The infinite rotor according to [Aspect 2] or [Aspect 3], wherein the piezoelectric element is disposed on an outer surface of the disk portion in the vehicle width direction.

[0013] [Aspect 7] The endless rotating body according to [Aspect 1], which is a steel wheel. According to the above configuration, the piezoelectric element can be disposed on the steel wheel. Effect of the Invention

[0014] According to the present invention, it is possible to increase the power generation efficiency in an infinite rotor having a piezoelectric element disposed on a disk portion. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view of a passenger vehicle wheel in a first embodiment, as viewed from the outer side in the vehicle width direction. [Diagram 2] FIG. 2 is a perspective view of the passenger vehicle wheel in the first embodiment, as viewed from the inner surface in the vehicle width direction. [Diagram 3] FIG. 3 is a diagram showing stress distribution on the outer surface in the vehicle width direction of the passenger vehicle wheel in the first embodiment. [Figure 4] FIG. 4 is a diagram showing stress distribution on the inner surface in the vehicle width direction of the passenger vehicle wheel in the first embodiment. [Diagram 5] FIG. 5 is a characteristic diagram showing the relationship between elapsed time and voltage when a piezoelectric element is disposed at the position of the annular protrusion on the inner surface in the vehicle width direction. [Figure 6] FIG. 6 is a characteristic diagram showing the relationship between elapsed time and voltage when a piezoelectric element is disposed between decorative holes on the outer surface in the vehicle width direction. [Figure 7]FIG. 7 is a perspective view of a passenger vehicle wheel according to the second embodiment, as viewed from the outer side in the vehicle width direction. [Figure 8] FIG. 8 is a perspective view of a passenger vehicle wheel according to the second embodiment, as viewed from the inner surface in the vehicle width direction. [Figure 9] FIG. 9 is a diagram showing stress distribution on the outer surface in the vehicle width direction of a passenger vehicle wheel in the second embodiment. [Figure 10] FIG. 10 is a diagram showing stress distribution on the inner surface in the vehicle width direction of a passenger vehicle wheel in the second embodiment. [Figure 11] FIG. 11 is a perspective view of a modified example of the second embodiment, in which a passenger vehicle wheel is viewed from the outer side. [Figure 12] FIG. 12 is a characteristic diagram showing the relationship between elapsed time and voltage when a piezoelectric element is disposed on the outer surface, between the holes, and at a position closer to the hub attachment portion than the disk flange portion. [Figure 13] FIG. 13 is a characteristic diagram showing the relationship between elapsed time and voltage when a piezoelectric element is disposed on the inner surface at a position along the outer periphery of the hub attachment portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, a wheel to which an infinite rotating body according to the present invention is applied will be described with reference to the drawings. First Embodiment <Wheel configuration> As shown in Figures 1 and 2, a vehicle wheel 10 according to the first embodiment is a wheel used in passenger cars and the like. The wheel 10 includes a rim portion 11 and a disc portion 12. The rim portion 11 and the disc portion 12 are made of metal. The rim portion 11 and the disc portion 12 are made of a metal that contains at least iron. Or, they are made of a metal that contains at least aluminum. The vehicle wheel 10 is a wheel that is roll-formed or press-formed from a steel plate. The disc portion 12 is welded to the annular rim portion 11 to form the wheel 10.

[0017] The rim portion 11 includes an inner flange portion 13, an inner bead seat portion 14, a drop portion 15, an outer bead seat portion 16, and an outer flange portion 17. The inner flange portion 13 and the inner bead seat portion 14 are located closer to the inner side (in) of the vehicle in the wheel axial direction than the outer bead seat portion 16 and the outer flange portion 17 when the wheel 10 is mounted on the vehicle. In other words, the outer bead seat portion 16 and the outer flange portion 17 are located closer to the outer side (out) of the vehicle in the wheel axial direction than the inner flange portion 13 and the inner bead seat portion 14 when the wheel 10 is mounted on the vehicle.

[0018] The disk portion 12 includes a hub hole 21 , a hub attachment portion 22 , a disk flange portion 23 , a window forming portion 24 , and a disk intermediate portion 25 . The hub hole 21 is provided in the center of the disk portion 12 in the disk radial direction (wheel radial direction).

[0019] The hub mounting portion 22 is provided around the hub hole 21. The hub mounting portion 22 is in a plane perpendicular to the disk axial direction (wheel axial direction). A plurality of hub mounting bolt holes 22a are provided in the hub mounting portion 22. For example, four hub mounting bolt holes 22a are provided at equal intervals in the disk circumferential direction (wheel circumferential direction). However, the number of hub mounting bolt holes 22a is not limited to four, and may be three, or five or more. Hub mounting bolts extending from the hub are inserted into the hub mounting bolt holes 22a. Hub nuts are screwed into the hub mounting bolts. In this way, the wheel 10 is fixed to the hub.

[0020] A plurality of disk flange portions 23 (four in this embodiment) are provided at intervals in the disk circumferential direction. The plurality of disk flange portions 23 are on the same circumference. The disk flange portions 23 extend in a direction parallel to the disk axial direction at the disk radial outer end. The disk flange portions 23 are fitted to the rim portion 11 at the drop portion 15 of the rim portion 11, and are welded to the inner peripheral surface of the drop portion 15. The disk flange portion 23 may be welded to the rim portion 11 over the entire disk circumferential area of ​​the disk flange portion 23, or may be welded to the rim portion 11 only at a portion including the central portion of the disk circumferential area of ​​the disk flange portion 23. The disk portion 12 is fixed to the rim portion 11 at the disk flange portion 23.

[0021] The window forming portions 24 are provided between adjacent disk flange portions 23 in the disk circumferential direction. The same number of window forming portions 24 are provided as there are disk flange portions 23. The window forming portions 24 are located radially inward of the disk flange portions 23. The window forming portions 24 are not in contact with the rim portion 11, and form a window between the window forming portions 24 and the rim portion 11. The window forming portions 24 are provided at positions corresponding to the hub mounting bolt holes 22a in the disk circumferential direction. The window forming portions 24 may also be provided at positions corresponding to between the hub mounting bolt holes 22a in the disk circumferential direction.

[0022] The disk intermediate portion 25 is a disk portion that connects the hub attachment portion 22 to the disk flange portion 23 and the window portion forming portion 24 in the disk radial direction. In the disk radial direction, the hub attachment portion 22 side of the disk intermediate portion 25 extends outward in the disk radial direction and outward in the disk axial direction from the hub attachment portion 22. In the disk radial direction, the disk flange portion 23 side and the window portion forming portion 24 side of the disk intermediate portion 25 extend outward in the disk radial direction and inward in the disk axial direction.

[0023] The disk intermediate portion 25 has an annular protrusion 26 that is continuous in the disk circumferential direction, protrudes in the disk axial direction, and is also continuous in the circumferential direction, at a disk radial intermediate portion of the disk intermediate portion 25. Also, the disk intermediate portion 25 is provided with a plurality of decorative holes 27 as holes at equal intervals in the disk circumferential direction, at a disk radial intermediate portion of the disk intermediate portion 25. When both the annular protrusion 26 and the decorative holes 27 are provided, the decorative holes 27 are provided on the outer side of the annular protrusion 26 in the disk radial direction.

[0024] <Piezoelectric element> Incidentally, the inner surface of the wheel 10 in the vehicle width direction is a surface that is difficult to see from the outside. The inner surface of the annular protrusion 26 in the vehicle width direction is an arrangement surface 29 on which a piezoelectric element 28 serving as a power generating element is arranged. The piezoelectric element 28 is arranged in a position in the disk portion 12 that is subjected to relatively high stress.

[0025] Here, Fig. 3 is a diagram showing the stress distribution on the surface of the wheel 10 on the outer side in the vehicle width direction, out, when a vehicle load is applied to the wheel 10 from all around. Also, Fig. 4 is a diagram showing the stress distribution on the surface of the wheel 10 on the inner side in the vehicle width direction, in, when a vehicle load is applied to the wheel 10 from all around. The darker the color, the higher the stress.

[0026] 3 and 4, it can be seen that the stress is higher at the position of the annular protrusion 26 than in other regions of the disk portion 12. The piezoelectric element 28 is a piezo element that generates a voltage when pressure is applied. The piezoelectric element 28 generates a voltage according to the distortion caused by applying pressure to the piezoelectric body. Therefore, the piezoelectric element 28 generates a voltage due to the stress fluctuation of the annular protrusion 26 during driving.

[0027] Moreover, the piezoelectric element 28 is a piezoelectric body. Either an inorganic piezoelectric body or an organic piezoelectric body is selected and used as the piezoelectric body depending on the arrangement position, etc. Inorganic piezoelectric bodies are poor in flexibility because they are mainly composed of ceramics, etc., but have high power generation efficiency. Organic piezoelectric bodies are excellent in flexibility but have low power generation efficiency. The type of piezoelectric element 28 is selected depending on the conditions such as the shape of the arrangement location. Moreover, the piezoelectric elements 28 arranged in the annular protrusion 26 are the same and have the same shape and output.

[0028] For example, as positions of high stress, the piezoelectric elements 28 are intermittently arranged at positions corresponding to the spaces between adjacent hub mounting bolt holes 22a on the annular arrangement surface 29. The piezoelectric elements 28 are also arranged at positions corresponding to the hub mounting bolt holes 22a on the annular arrangement surface 29. The piezoelectric elements 28 are further arranged at positions corresponding to the spaces between adjacent hub mounting bolt holes 22a on the annular arrangement surface 29 and at positions corresponding to the hub mounting bolt holes 22a on the annular arrangement surface 29. The piezoelectric elements 28 are arranged at equal intervals on the annular arrangement surface 29. The piezoelectric elements 28 may be arranged at the same period on the annular arrangement surface 29. The piezoelectric elements 28 may be provided continuously, i.e., uninterruptedly, in the circumferential direction on the annular arrangement surface 29.

[0029] This arrangement makes it possible to prevent the outputs of adjacent piezoelectric elements 28 from cancelling each other out. A predetermined periodic output voltage can be obtained from piezoelectric element 28. When the output voltage of piezoelectric element 28 increases, the output current also increases accordingly, and the generated power (power generation efficiency) also increases.

[0030] Here, the output voltage was confirmed when the piezoelectric element 28 was attached to the arrangement surface 29 on the inside (in) of the annular protrusion 26 in the wheel 10 shown in Figures 1 to 4 (part A in Figure 2), and when the piezoelectric element 28 was attached to a position between the decorative holes 27 on the outside (out) in the vehicle width direction. Figure 5 is a characteristics diagram showing the relationship between elapsed time and voltage when the piezoelectric element 28 is arranged at the position of the annular protrusion 26 on the surface on the inside (in) in the vehicle width direction. Figure 6 is a characteristics diagram showing the relationship between elapsed time and voltage when the piezoelectric element 28 is arranged at a position between the decorative holes 27 on the surface on the outside (out) in the vehicle width direction. In Figures 5 and 6, the vertical and horizontal axes have the same scale.

[0031] <Measurement conditions> Wheels / Tires: 14×41 / 2 / 155 / 65R14 Air pressure: 220kPa Test load: 3.7kN Test speed: 10km / h 5 and 6, it can be seen that a higher output voltage can be obtained when the piezoelectric element 28 is attached to the arrangement surface 29 on the back side of the annular protrusion 26 (part A in FIG. 2) than when the piezoelectric element 28 is attached to a position between the decorative holes 27 on the outer side out in the vehicle width direction (part B in FIG. 1). This is because the arrangement surface 29 has a higher stress than the positions between the decorative holes 27.

[0032] The power generated by the piezoelectric element 28 is stored in a secondary battery such as a lithium ion secondary battery or a nickel hydrogen secondary battery. The secondary battery is, for example, for vehicle mounting and is arranged on the chassis. In this case, the power generated by the piezoelectric element 28 is stored in the secondary battery arranged on the chassis and is used as part of the power of the vehicle. The secondary battery may also be arranged on the wheel 10. For example, the wheel 10 may be decorated with light-emitting elements such as LEDs. The wheel 10 may also be arranged with a detection element such as a sensor for detecting an abnormality in fastening with the hub. These elements and a communication element for exchanging detection data and control data with other communication devices are supplied with power from the secondary battery arranged on the wheel 10. The power generated by the piezoelectric element 28 is stored in the secondary battery arranged on the wheel 10.

[0033] <Advantages of the First Embodiment> The wheel 10 described above can provide the following effects. (1-1) By arranging the piezoelectric element 28 on the wheel 10, the piezoelectric element 28 is less likely to break down than if it were arranged in the tire.

[0034] (1-2) The annular protrusion 26 is a position where stress is concentrated more than other portions of the disk portion 12. Therefore, by disposing the piezoelectric element 28 on the annular protrusion 26, power generation efficiency can be improved.

[0035] (1-3) By arranging the piezoelectric elements 28 at intervals on the annular protrusion 26, it is possible to prevent the outputs of adjacent piezoelectric elements 28 from cancelling each other out. (1-4) By arranging the piezoelectric element 28 on the arrangement surface 29, which is the surface on the inner side in the vehicle width direction of the annular protrusion 26, the piezoelectric element 28 can be made difficult to see from the outer side out in the vehicle width direction.

[0036] (1-5) Since the piezoelectric element 28 is disposed on the arrangement surface 29 of the annular protrusion 26, which is a part of the disk portion 12, wiring to the secondary battery is facilitated. For example, if the piezoelectric element 28 is disposed on the outer circumferential surface of the rim portion 11, a through hole or the like connecting to the inner circumferential side of the rim portion 11 is required for wiring. In this regard, if the piezoelectric element 28 is disposed on the arrangement surface 29 of the annular protrusion 26, there is no need to provide a through hole for wiring in the rim portion 11, whether the piezoelectric element 28 is disposed on a secondary battery vehicle or in the inner space of the wheel 10. Therefore, if the piezoelectric element 28 is disposed on the arrangement surface 29 of the annular protrusion 26, wiring to the secondary battery can be facilitated.

[0037] (1-6) Piezoelectric elements 28 can also be arranged on the steel wheels. <Second embodiment> As shown in Figs. 7 and 8, a vehicle wheel 30 according to the second embodiment is a wheel used for trucks, buses, commercial vehicles, etc. The wheel 30 includes a rim portion 31 and a disc portion 32. The rim portion 31 and the disc portion 32 are made of metal. The rim portion 31 and the disc portion 32 are made of a metal containing at least iron. Or, they are made of a metal containing at least aluminum. The wheel 30 is a wheel that is roll-formed or press-formed from a steel plate. The disc portion 32 is welded to the annular rim portion 31 to form the wheel 30.

[0038] The rim portion 31 includes an inner flange portion 33, an inner bead seat portion 34, a drop portion 35, an outer bead seat portion 36, and an outer flange portion 37. The inner flange portion 33 and the inner bead seat portion 34 are located closer to the inner side (in) of the vehicle in the wheel axial direction than the outer bead seat portion 36 and the outer flange portion 37 when the wheel 30 is mounted on the vehicle. In other words, the outer bead seat portion 36 and the outer flange portion 37 are located closer to the outer side (out) of the vehicle in the wheel axial direction than the inner flange portion 33 and the inner bead seat portion 34 when the wheel 30 is mounted on the vehicle.

[0039] The disk portion 32 includes a hub hole 41, a hub attachment portion 42, a disk middle portion 43, and a disk flange portion 44. The hub hole 41 is provided in the center of the disk portion 12 in the disk radial direction (wheel radial direction).

[0040] The hub mounting portion 42 is provided around the hub hole 41. The hub mounting portion 42 is flat and lies within a plane intersecting the disk axial direction (wheel axial direction). A plurality of hub mounting bolt holes 42a are provided in the disk radial middle portion of the hub mounting portion 42. The hub mounting bolt holes 42a are provided at equal intervals on a concentric circle in the disk circumferential direction (wheel circumferential direction). Hub mounting bolts extending from the hub are inserted into the hub mounting bolt holes 42a. Hub nuts are screwed into the hub mounting bolts. This fixes the wheel 30 to the hub.

[0041] The disc flange portion 44 is a portion that is fitted into and joined to the rim portion 31. The disc flange portion 44 is joined to the outer bead seat portion 36 by welding, riveting, adhesive, or the like. The disc flange portion 44 may be joined to the drop portion 35.

[0042] The disk intermediate portion 43 is provided between the hub mounting portion 42 and the disk flange portion 44 in the disk radial direction, and is a portion that connects the hub mounting portion 42 and the disk flange portion 44 in the disk radial direction. The disk intermediate portion 43 has a portion that is located axially outward of the hub mounting portion 42 and the disk flange portion 44. At least a top portion of the disk intermediate portion 43 is located axially outward of the hub mounting portion 42 and the disk flange portion 44.

[0043] The disc flange portion 44 is a portion that is fitted into and joined to the rim portion 31. The disc flange portion 44 is joined to the outer bead seat portion 36 by welding, riveting, adhesive, or the like. The disc flange portion 44 may be joined to the drop portion 35.

[0044] The disk intermediate portion 43 is provided between the hub mounting portion 42 and the disk flange portion 44 in the disk radial direction, and is a portion that connects the hub mounting portion 42 and the disk flange portion 44 in the disk radial direction. In the disk radial direction, the hub mounting portion 42 side of the disk intermediate portion 43 extends outward in the disk radial direction and outward in the disk axial direction from the hub mounting portion 42. In the disk radial direction, the disk flange portion 44 side of the disk intermediate portion 43 extends outward in the disk radial direction and inward in the disk axial direction.

[0045] The disc intermediate portion 43 is formed with decorative holes 45 as holes. The decorative holes 45 are, for example, circular. The decorative holes 45 are provided in the radially intermediate portion of the disc intermediate portion 43. A plurality of the decorative holes 45 are provided at equal intervals in the circumferential direction of the disc. Between the decorative holes 45 are connecting regions 46 that function as spokes connecting an area on the inner periphery side of the decorative holes 45 in the disc intermediate portion 43 with an area on the outer periphery side.

[0046] <Piezoelectric element> Incidentally, the inner surface of the wheel 30 in the vehicle width direction is a surface that is difficult to see from the outside. In the connecting region 46, the inner surface in the vehicle width direction is an arrangement surface 48 on which a piezoelectric element 47 serving as a power generating element is arranged. The piezoelectric element 47 is arranged in a position in the disk portion 32 that is subjected to relatively high stress.

[0047] Here, Fig. 9 is a diagram showing stress distribution on the surface of the outer side out of the wheel 30 in the vehicle width direction when a vehicle load is applied to the wheel 30 from all around. Also, Fig. 10 is a diagram showing stress distribution on the surface of the inner side in of the wheel 30 in the vehicle width direction when a vehicle load is applied to the wheel 30 from all around. The darker the color, the higher the stress.

[0048] 9 and 10, it can be seen that the stress is higher in the connecting region 46 than in other regions of the disk portion 32. More specifically, the position of high stress is a position adjacent to the two decorative holes 45 between the two decorative holes 45, and is closer to the hub mounting portion 42 than the disk flange portion 44. The piezoelectric element 47 is disposed so as to straddle the two high stress positions adjacent to the two decorative holes 45 that constitute the connecting region 46. The piezoelectric element 47 generates a voltage due to stress fluctuations in that region during driving. The piezoelectric element 47 is a piezo element that generates a voltage when pressure is applied.

[0049] Moreover, the piezoelectric element 47 is, for example, a piezoelectric body. An inorganic piezoelectric body or an organic piezoelectric body is selected and used as the piezoelectric body depending on the arrangement position, etc. Inorganic piezoelectric bodies are poor in flexibility because they are mainly composed of ceramics, etc., but have high power generation efficiency. Organic piezoelectric bodies are excellent in flexibility but have low power generation efficiency. The type of piezoelectric element 47 is selected depending on the conditions such as the shape of the arrangement location. Furthermore, the piezoelectric elements 47 arranged in a position adjacent to the decorative holes 45 between the two decorative holes 45 and closer to the hub mounting portion 42 than the disk flange portion 44 are the same and have the same shape and output.

[0050] The piezoelectric element 47 is disposed adjacent to the decorative holes 45 between the two decorative holes 45, and at a position closer to the hub mounting portion 42 than the disc flange portion 44. The piezoelectric elements 47 are disposed periodically and intermittently in the circumferential direction. By disposing the piezoelectric elements 47 in this manner, it is possible to prevent the outputs of adjacent piezoelectric elements 28 from cancelling each other out. It can also be confirmed that the piezoelectric element 47 is capable of obtaining an output voltage with a predetermined period. When the output voltage of the piezoelectric element 47 increases, the output current also increases accordingly, and the generated power (power generation efficiency) also increases.

[0051] The power generated by the piezoelectric element 47 is stored in a secondary battery such as a lithium ion secondary battery or a nickel hydrogen secondary battery. The secondary battery is, for example, for vehicle mounting and is arranged on the chassis. In this case, the power generated by the piezoelectric element 47 is stored in the secondary battery arranged on the chassis and is used as part of the power of the vehicle. The secondary battery may also be arranged on the wheel 30. For example, the wheel 30 may be decorated with light-emitting elements such as LEDs. The wheel 30 may also be arranged with a detection element such as a sensor for detecting a fastening abnormality with the hub. These elements and communication elements for exchanging detection data and control data with other communication devices are supplied with power from the secondary battery arranged on the wheel 30. The power generated by the piezoelectric element 28 is stored in the secondary battery arranged on the wheel 10.

[0052] <Effects of the second embodiment> The above-described wheel 30 can provide the following effects. (2-1) By arranging the piezoelectric element 47 on the wheel 30, the piezoelectric element 47 is less likely to break down than if it were arranged on the tire.

[0053] (2-2) In the arrangement surface 48 of the connecting region 46, a position between two decorative holes 45 adjacent to the decorative holes 45 and closer to the hub mounting portion 42 than the disk flange portion 44 is a position where stress is concentrated more than other portions of the disk portion 32. Therefore, by arranging the piezoelectric element 47 in this region, power generation efficiency can be improved.

[0054] (2-3) The piezoelectric elements 47 are disposed at positions adjacent to the decorative holes 45 between the two decorative holes 45 and closer to the hub attachment portion 42 than the disc flange portion 44, so that the piezoelectric elements 47 are disposed intermittently in the circumferential direction. This makes it possible to prevent the outputs of adjacent piezoelectric elements 28 from cancelling each other out.

[0055] (2-4) The piezoelectric element 47 is disposed on the arrangement surface 48, which is the surface on the inner side in the vehicle width direction of the connecting region 46, so that it can be made difficult to see from the outer side out in the vehicle width direction. (2-5) The piezoelectric element 47 is disposed on the arrangement surface 48 of the connecting region 46, which is a part of the disk portion 32, at a position adjacent to the decorative hole 45 between the two decorative holes 45, and at a position closer to the hub attachment portion 42 than the disk flange portion 44. This facilitates wiring to the secondary battery. For example, if the piezoelectric element 47 is disposed on the outer circumferential surface of the rim portion 11, a through hole or the like that connects to the inner circumferential side of the rim portion 31 is required for wiring. In this regard, if the piezoelectric element 47 is disposed on the arrangement surface 48 of the connecting region 46, it is not necessary to provide a through hole for wiring in the rim portion 31, even if the piezoelectric element 47 is disposed on a secondary battery vehicle or in the inner space of the wheel 30. Therefore, if the piezoelectric element 47 is disposed on the arrangement surface 48 of the connecting region 46, wiring to the secondary battery can be easily performed.

[0056] (2-6) Piezoelectric elements 47 can also be arranged on the steel wheels. <Modification of the second embodiment> In the second embodiment described above, the piezoelectric element 47 is disposed on the arrangement surface 48, which is the surface (first surface) on the inside in the vehicle width direction. In contrast, in FIG. 11 as a modified example of the second embodiment, the piezoelectric element 47 is disposed on the surface (second surface) on the outside out in the vehicle width direction. In the case of a commercial vehicle or the like, the rear wheels may be dual tires. In such a case, the surface on which the piezoelectric element 47 is disposed may be the outer out surface (second surface) or the inner in surface (first surface) depending on whether the wheel 30 is disposed on the inside or the outside. For example, in the wheel 30 located on the inside of a dual tire, the piezoelectric element 47 is disposed on the inner in surface (first surface) as shown in FIG. 8, and the piezoelectric element 47 is disposed on the outer out surface (second surface) as shown in FIG. 11 for the wheel 30 disposed on the outside.

[0057] In addition, when a double tire is assumed, the outer surface and the inner surface of the wheel 30 located on the inside and the wheel 30 located on the outside will not show the same surface. Therefore, here, with the wheel 30 located on the inside as a reference, the inner surface IN in the vehicle width direction will be referred to as the first surface, and the outer surface OUT will be referred to as the second surface.

[0058] 9, even on the outer surface (second surface), the position at which the piezoelectric element 47 is disposed is a position adjacent to the decorative holes 45 between the two decorative holes 45 in the connecting region 46, and is a position closer to the hub mounting portion 42 than the disk flange portion 44. Therefore, on the outer surface (second surface), the piezoelectric element 47 is disposed so as to straddle two high stress positions adjacent to the two decorative holes 45 that constitute the connecting region 46. In such a case, the piezoelectric element 47 may be made inconspicuous and protected by covering it with an accessory part.

[0059] Here, in the wheel 30 shown in Figures 7 to 11, the output voltage was confirmed when the piezoelectric element 28 was placed at two high stress positions (part A in Figure 11) adjacent to two decorative holes 45 on the outer surface (second surface) of the wheel 30, and when the piezoelectric element 47 was placed at a position (part B in Figure 8) along the outer periphery of the hub mounting part 42 on the inner surface (first surface). Note that the position of part B in Figure 8 is a position that is more inward than the position of part A in Figure 11, is closer to the hub mounting part 42, and does not overlap with the position of part A.

[0060] Fig. 12 is a characteristics diagram showing the relationship between elapsed time and voltage when a piezoelectric element 47 is placed on the outer surface (second surface) between two decorative holes 45 and closer to the hub mounting portion 42 than the disk flange portion 44 (part A in Fig. 11). Fig. 13 is a characteristics diagram showing the relationship between elapsed time and voltage when a piezoelectric element 47 is placed on the inner surface (first surface) at a position along the outer periphery of the hub mounting portion 42 (part B in Fig. 8). The vertical scale is the same in Figs. 12 and 13.

[0061] <Measurement conditions> Wheels / Tires: 22.5×7.50 / 275 / 80R22.5 Air pressure: 900kPa Test load: 16.9kN Test speed: 15km / h From Figures 12 and 13, it can be seen that when the piezoelectric element 28 is attached at the two high stress positions adjacent to the two decorative holes 45 that make up the connecting region 46 (part A in Figure 11), a higher output voltage can be obtained than when the piezoelectric element 47 is attached at a position along the outer periphery of the hub mounting portion 42 (part B in Figure 8).

[0062] The first and second embodiments can also be modified as necessary as follows. In the first and second embodiments, the metal of the wheel 10 may be aluminum. It may also be a titanium alloy, a magnesium alloy, or the like.

[0063] In the first embodiment, the piezoelectric element 28 may be disposed on the surface of the annular protrusion 26 that is on the outer side in the vehicle width direction. In this case, the piezoelectric element 28 can be made inconspicuous and protected by covering the piezoelectric element 28 with an accessory part.

[0064] In the first embodiment, the piezoelectric element 28 may be arranged only on the arrangement surface 29, which is the surface on the inside in the vehicle width direction of the annular protrusion 26, or only on the surface on the outside out in the vehicle width direction. Furthermore, the piezoelectric element 28 may be arranged on both the arrangement surface 29, which is the surface on the inside in the vehicle width direction, and the surface on the outside out in the vehicle width direction. Furthermore, the piezoelectric element 28 may be arranged on the outer circumferential surface or inner circumferential surface of the rim portion 11. When arranged on the rim portion 11, it is preferable to arrange it in the drop portion 15.

[0065] In the first embodiment, the annular protrusions 26 may be discontinuous in the circumferential direction. The annular protrusions 26 may be provided at equal intervals in the circumferential direction. In the second embodiment, whether a single tire or a dual tire is used, the piezoelectric element 47 may be disposed on both the surface on the inner side in the vehicle width direction (in) and the surface on the outer side in the vehicle width direction (out) at a position adjacent to the decorative hole 45 between the two decorative holes 45 in the connecting region 46 and closer to the hub mounting portion 42 than the disc flange portion 44. Furthermore, when a further piezoelectric element is disposed on the rim portion 31, it is preferable to dispose it in the drop portion 35 or the like.

[0066] The piezoelectric element may be disposed at any position within the disk portion where stress is relatively high during running other than the positions in the first and second embodiments. In the case of an aluminum wheel, the wheel may be made up of two parts: a rim portion and a disc portion having a hub attachment portion and spokes. In this case, the rim portion and the disc portion are joined by bolts and nuts, welding, etc. Furthermore, the rim portion may be divided in the axle direction and made up of three parts.

[0067] In the case of aluminum wheels, the wheels are cast wheels, forged wheels formed by press drawing from steel plates, or forged aluminum wheels formed from bullets or castings. As an infinite rotating body, the wheel 10 of the first embodiment may be a wheel used for a commercial vehicle, etc. Also, the wheel 30 of the second embodiment may be a wheel used for a passenger car, etc. In addition, the infinite rotating body may be applied to wheels of work vehicles, bicycle wheels, and railway wheels. [Explanation of symbols]

[0068] 10…Wheels 11…Rim section 12...Disc section 13…Inner flange 14…Inner bead seat 15…Drop section 16...Outer bead seat 17…Outer flange 21…Hub hole 22…Hub mounting part 22a…Hub mounting bolt hole 23...Disc flange 24…Window forming section 25…Disc middle part 26…Ring-shaped protrusion 27...Decorative hole 28...Piezoelectric element 29...Placement surface

Claims

1. A rim portion and a disk portion disposed inside the annulus of the rim portion; The disk portion has a piezoelectric element disposed at a position where stress is relatively high during running. Infinite rotating body.

2. the disk portion includes a hub attachment portion, a disk flange portion, and a plurality of holes periodically arranged in a circumferential direction between the hub attachment portion and the disk flange portion, and includes an annular protrusion that is continuous or discontinuous in the circumferential direction between the hub attachment portion and the holes, The position where the piezoelectric element is disposed is the annular protrusion. The infinite rotating body according to claim 1 .

3. the disk portion includes a hub attachment portion, a disk flange portion, and a plurality of holes that are periodically arranged in a circumferential direction between the hub attachment portion and the disk flange portion; The position where the piezoelectric element is disposed is between the holes and is closer to the hub attachment portion than the disk flange portion. The infinite rotating body according to claim 1 .

4. The piezoelectric elements are arranged intermittently at the same interval in the circumferential direction.

4. An infinite rotating body according to claim 2 or 3.

5. The piezoelectric element is disposed on an inner surface of the disk portion in a vehicle width direction.

4. An infinite rotating body according to claim 2 or 3.

6. The piezoelectric element is disposed on an outer surface of the disk portion in a vehicle width direction.

4. An infinite rotating body according to claim 2 or 3.

7. Steel wheels The infinite rotating body according to claim 1 .

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