Tire and wireless power supply system

Abstract

To provide a tire which can realize, when a steel cord is used for a belt, excellent power supply efficiency without allowing magnetic field from a power-feeding coil to a power-receiving coil from being disturbed by a metallic component.SOLUTION: A tire includes in a tire meridian cross sectional view: a power-receiving coil (40) which is arranged at a tire radial direction area (WH) from a tire radial direction outermost position of a bead core (14) to a tire radial direction innermost position of a belt (20). Dielectric constant of components except tread part arranged in the tire radial direction area is 3.5 or more and 250 or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a tire with improved power supply efficiency and a wireless power supply system.

Background Art

[0002] Conventionally, a wireless power reception system has been disclosed in which power is supplied between a power transmission coil buried near a road surface and a power reception coil attached on the center line in the tire width direction of a wheel (for example, Patent Document 1, FIG. 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the wireless power reception system of Patent Document 1, it is disclosed that a steel cord can be used for a belt constituting a tire (

[0022] ). However, when a steel cord is used for the belt, a part of the magnetic field that should reach the power reception coil from the power transmission coil may be blocked by the belt, and thus it may not be possible to achieve excellent power supply efficiency.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a tire and a wireless power supply system using the tire, in which even when a steel cord is used for the belt, the magnetic field reaching the power reception coil from the power transmission coil is not obstructed by a metal member existing between the two coils, and excellent power supply efficiency can be achieved.

Means for Solving the Problems

[0006] The tire of the present invention has a bead core, a bead filler provided on the outer side in the tire radial direction of the bead core, a carcass folded around the bead core, and a belt provided on the outer side in the tire radial direction of the carcass, and is provided with a power receiving coil on the inner cavity surface of the tire for receiving power supplied by an alternating magnetic field from the outside of the tire. In a tire meridian cross-sectional view, the power receiving coil is provided in a tire radial region from the outermost position in the tire radial direction of the bead core to the innermost position in the tire radial direction of the belt, and the relative permittivity of the members arranged in the tire radial region, excluding the tread portion, is 3.5 or more and 250 or less.

Advantages of the Invention

[0007] In the tire according to the present invention, improvements have been made to the position of the power receiving coil on the inner cavity surface of the tire and the relative permittivity of the members. As a result, according to the tire of the present invention, the power supply efficiency can be improved.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

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Figure 8

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Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Embodiments for Carrying Out the Invention

[0009] Hereinafter, the tire according to the present invention (basic form 1 and additional forms 2 to 13 shown below), and embodiments of the wireless power supply system according to the present invention (basic form 14 and additional forms 15 to 17 shown below) will be described in detail with reference to the drawings. Note that these embodiments do not limit the present invention. Also, the constituent elements of each embodiment include those that can be replaced and are easy for those skilled in the art, or those that are substantially the same. Furthermore, each embodiment can be arbitrarily combined within the scope obvious to those skilled in the art.

[0010] In the following description, the tire radial direction refers to the direction orthogonal to the tire rotation axis. The inner side in the tire radial direction refers to the side facing the tire rotation axis in the tire radial direction, and the outer side in the tire radial direction refers to the side away from the tire rotation axis in the tire radial direction. Further, the tire circumferential direction refers to the circumferential direction centered on the tire rotation axis. Furthermore, the tire width direction refers to the direction parallel to the tire rotation axis. The inner side in the tire width direction refers to the side facing the tire equatorial plane (tire equator line) in the tire width direction, and the outer side in the tire width direction refers to the side away from the tire equatorial plane in the tire width direction. Note that the tire equatorial plane refers to a plane that is orthogonal to the tire rotation axis and passes through the center of the tire width.

[0011] Similarly, in the following description, the standard rim refers to the "Applicable Rim" defined by JATMA, the "Design Rim" defined by TRA, or the "Measuring Rim" defined by ETRTO.

[0012] Similarly, in the following description, the standard internal pressure refers to the "Maximum Air Pressure" defined by JATMA, the maximum value described in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" defined by TRA, or the "INFLATION PRESSURES" defined by ETRTO. Also, the standard load refers to the "Maximum Load Capacity" defined by JATMA, the maximum value described in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" defined by TRA, or the "LOAD CAPACITY" defined by ETRTO.

[0013] <Tire> [Basic Form 1] FIG. 1 is a tire meridian cross-sectional view showing a part on one side in the tire width direction with respect to the tire according to the present embodiment, with reference to the tire equatorial plane (not shown). Note that in the figure, the tire part on the side opposite to the ground contact surface is shown in a state where it is assembled with a rim and the standard internal pressure is applied and the standard load is applied (hereinafter, the same applies to the invention of the tire).

[0014] As shown in FIG. 1, the tire 10 according to the present embodiment has, from the inner side to the outer side in the tire radial direction, a bead portion A, a sidewall portion B, a shoulder portion C, and a tread portion D. In the region from the bead portion A to the tread portion D, an inner liner 12 exposed on the inner cavity surface of the tire is provided. On the side opposite to the inner cavity surface of the inner liner 12, a carcass 18 is provided, which includes a main body portion 18a extending along the inner liner 12 and a folded-back portion 18b folded back around the bead core 14 and the bead filler 16. On the outer side in the tire radial direction of the carcass 18 in the tread portion D, a belt 20 (belt layers 20a, 20b) and a belt cover 22 (belt cover layers 22a, 22b, 22c) are sequentially provided on the outer side in the tire radial direction.

[0015] Further, on the outer side in the tire width direction of the folded-back portion 18b of the carcass 18 provided on the outer side in the tire width direction of the bead core 14 and the bead filler 16, a rim cushion 24 is provided. On the outer side in the tire radial direction of the rim cushion 24, a side tread 26, a wing tip 28, and a cap tread 30 are sequentially provided.

[0016] FIG. 2 shows a case where the tire 10 of FIG. 1 further includes a run-flat liner 32. The run-flat liner 32 is formed on the outer side in the tire width direction of the inner liner 12 over at least the sidewall portion B (and in some cases, also includes the bead portion A and the shoulder portion C). The tire according to the present embodiment is not limited to the example shown in FIG. 1, and includes a run-flat tire in which, as shown in FIG. 2, for example, the run-flat liner 32 is provided on the outer side in the tire width direction of the inner liner 12 mainly in the sidewall portion B.

[0017] Further, FIG. 3 shows a case where the tire 10 of FIG. 1 further includes a second filler 25. The second filler 25 is made of a rubber different from the rim cushion 24 and is provided on the outer side in the tire width direction of the folded portion 18b so as to be adjacent to the folded portion 18b of the carcass 18 as in the illustrated example. Further, FIG. 4 shows a case where the tire 10 of FIG. 1 further includes a steel reinforcement (SRF) 19. The steel reinforcement 19 is provided on the inner side in the tire width direction of the folded portion 18b so as to be adjacent to the folded portion 18b of the carcass 18 as in the illustrated example. By providing the second filler 25 or the steel reinforcement 19, the rigidity of the sidewall portion B can be improved. The tire according to the present embodiment is not limited to the example shown in FIG. 1, and also includes tires provided with the second filler 25 or the steel reinforcement 19 as shown in FIGS. 3 and 4.

[0018] In the tire 10 having the configuration shown above, the inner liner 12 is a layer for blocking the gas in contact with the inner cavity surface of the tire. The inner liner 12 can be composed of a single inner liner layer, or can also be composed of a plurality of inner liner layers laminated in the tire radial direction at the tire equatorial plane. The inner liner 12 includes at least one layer made of a rubber or resin layer with low air permeability, and as other layers, it can include an adhesive layer at least at the contact portion with the carcass 18.

[0019] The bead core 14 is, for example, a ring-shaped reinforcing material formed by bundling cords, and can have a structure in which a plurality of bead wires made of steel cords or organic fiber cords are coated with rubber. The bead filler 16 is a member for increasing the rigidity of the bead portion A, and the tire width direction dimension at the inner end portion in the tire radial direction thereof is substantially equal to the tire width direction dimension at the outer end portion in the tire radial direction of the bead core 14, and can have a substantially triangular shape as shown in FIG. 1 in which the tire width direction dimension gradually decreases toward the outer side in the tire radial direction.

[0020] The carcass 18 is a member that forms the framework of the tire 10 and is composed of at least one carcass layer (carcass ply). Each carcass layer has a structure in which a plurality of carcass cords are coated with rubber. Generally, steel cords or organic fiber cords are used as the carcass cords. However, in the tire 10 according to the present embodiment, as will be described later, in order to prevent the magnetic field generated so as to penetrate substantially perpendicularly to the inner cavity surface of the inner liner 12 in the sidewall portion B from being obstructed by a metal member, it is preferable to use a non-magnetic material as the carcass cord. For example, as the non-magnetic material, organic fibers such as rayon, polyester, polyamide, and aramid can be used.

[0021] The belt 20 is a reinforcing layer provided on the outer side in the tire radial direction of the carcass 18. It is a member that tightens the carcass 18 to increase the rigidity of the tread portion D, improve the handling stability, and reduce the rolling resistance by reducing the strain deformation. The belt 20 can be composed of a plurality of belt layers (two belt layers 20a and 20b in the example shown in FIG. 1) laminated in the tire radial direction in the tread portion D. Each of the belt layers 20a and 20b has a structure in which a plurality of belt cords are coated with rubber. Generally, steel cords or organic fiber cords are used as the belt cords. As the belt cord, not only a magnetic material such as a steel cord can be used, but also a non-magnetic material (including paramagnetic materials and diamagnetic materials) can be used.

[0022] The belt cover 22 is a member that reinforces the tightening effect of the carcass 18 by the belt 20, and is particularly a member for preventing the tread portion D from deforming due to the centrifugal force generated during high-speed running of the vehicle. The belt cover 22 can be constituted by a plurality of belt cover layers (in the example shown in FIG. 1, three belt cover layers 22a, 22b, 22c) laminated in the tire diameter direction on the outer side in the tire diameter direction of the belt 20. Each of the belt cover layers 22a, 22b, 22c has a configuration in which a plurality of cords are covered with rubber. Generally, as the cords used for the belt cover layer, steel cords or organic fiber cords are used. As this cord, not only magnetic materials such as steel cords can be used, but also non-magnetic materials (including paramagnetic materials and diamagnetic materials) can be used.

[0023] The rim cushion 24 is provided in a region that contacts a rim flange of a wheel (not shown), and the side tread 26 is arranged so as to connect the rim cushion 24 and the tread portion D. The wing tips 28 are respectively provided at the boundaries between the left and right tread portions D of the tire and the side tread 26 in a tire meridian cross-sectional view, and the cap tread 30 is formed on the surface of the tread portion D over the entire area of the tire ground contact surface. Note that for the rim cushion 24, the second filler 25, the side tread 26, the wing tips 28, the cap tread 30, and the run-flat liner 32, rubber members conventionally used can be used according to their respective required characteristics.

[0024] On the premise of the existence of the components 12 to 30 of the tire 10 shown in FIG. 1 (in some cases, including at least any one of the run-flat liner 32 in FIG. 2, the second filler 25 in FIG. 3, and the steel belt reinforcement 19 in FIG. 4), the tire 10 according to the present embodiment includes a power receiving coil 40 (FIG. 1) that receives AC power transmitted from a power transmission coil (not shown) installed outside the tire 10 on the inner side in the tire width direction of the tire inner cavity surface. Here, the power transmission may be, for example, by a magnetic field resonance method. The power receiving coil 40 may be provided in contact with the inner liner 12, or may be embedded in the inner liner 12. Further, the power receiving coil 40 may be provided so as to be fixed to the inner liner 12 via a fixing member other than rubber (for example, made of a non-magnetic material, but in particular, a rubber having a relatively high thermal conductivity such as silicone rubber can be used for the fixing part) (FIG. 1). In addition, even when a run-flat liner is provided, the power receiving coil 40 can be provided on the inner peripheral side of the inner liner 12 described above.

[0025] For the power supply using the tire 10 according to the present embodiment, for example, a DC current obtained from an in-vehicle battery (not shown) is once converted into an AC current by an AC power supply device, and this AC current is applied to a power transmission coil (attached to the surface on the tire side of any part of a knuckle or a hub carrier, which are parts of a vehicle's steering axle, or any part constituting a strut structure), thereby generating an AC magnetic field around the power transmission coil. When this AC magnetic field intersects the power receiving coil 40, an induced electromotive force is generated in the power receiving coil 40 and power is supplied.

[0026] In realizing such power supply, in the tire 10 according to the present embodiment, in a tire meridian cross-sectional view (FIG. 1), the power receiving coil 40 is provided in a tire radial region from the outermost position in the tire radial direction of the bead core 14 (point P1 shown in FIGS. 1 to 3) to the innermost position in the tire radial direction of the belt 20 (point P2 shown in FIGS. 1 to 3). As shown in FIG. 1, the tire radial region has a length WH in the tire radial direction in a tire meridian cross-sectional view and is a region extending in the tire width direction. Hereinafter, for convenience of explanation, the tire radial region is represented by the symbol WH.

[0027] The tire radial region WH is, more specifically, a region in the tire radial direction defined by the radially outer end (point P1) of the bead core 14 that may contain a ferromagnetic material and the innermost position in the tire radial direction (point P2, the radially outer end of the belt 20 in the tire width direction) of the belt 20 that may contain a ferromagnetic material, and is a region radially outside point P1 and radially inside point P2. In the tire radial region WH, since the tire 10 is curved in a convex shape outward, when the power receiving coil 40 is provided in the tire radial region WH, the power receiving coil 40 will basically be disposed radially outside points P1 and P2 in the tire width direction. However, this is not always the case depending on the positions of points P1 and P2 in the tire width direction. That is, when point P1 is clearly radially inside point P2 in the tire width direction and the power receiving coil 40 is disposed near the bead core 14, it may be disposed radially inside the widthwise end (point P2) of the belt 20 in the tire width direction. Also, when point P1 is clearly radially outside point P2 in the tire width direction and the power receiving coil 40 is disposed near the belt 20, it may be disposed radially inside the radially outer end (point P1) of the bead core 14 in the tire width direction.

[0028] In FIGS. 1 to 3, a case where there is no ferromagnetic reinforcing material around the bead core 14 is shown. On the other hand, FIG. 4 shows a case where a steel reinforcement (SRF) 19 is provided as a ferromagnetic reinforcing material around the bead core 14 (radially outside the bead core 14 in the tire radial direction). In the case of the tire 10 shown in FIG. 4, the innermost position in the tire radial direction of the tire radial region WH is point P3 shown in FIG. 4.

[0029] Also, in the tire 10 according to the present embodiment, the relative permittivity (the ratio of the permittivity of a specific member to the permittivity of a vacuum. The same applies hereinafter.) of the members other than the tread portion D disposed in the tire radial region WH from the outermost position in the tire radial direction of the bead core 14 to the innermost position in the tire radial direction of the belt 20 is 3.5 or more and 250 or less. The "members other than the tread portion D" means the remaining members excluding the cap tread 30, wing tip 28, belt cover 22, belt edge cushion, etc.

[0030] (Function, etc.) As described above, a wireless power receiving system that supplies power between a power transmission coil buried near a road surface and a power receiving coil attached on the center line in the tire width direction of a wheel has been conventionally known (Patent Document 1, FIG. 1). In this wireless power receiving system, the magnetic field reaching the power receiving coil from the power transmission coil may be affected by the belt. For example, in this wireless power receiving system, when a metal belt cord is used for the belt, a part of the magnetic field that should reach the power receiving coil from the power transmission coil is blocked by the magnetic material (belt cord) contained in the belt, and as a result, it may not be possible to achieve excellent power supply efficiency.

[0031] Therefore, the inventor has earnestly studied a tire 10 that can achieve excellent power supply efficiency without a part of the magnetic field that should reach the power receiving coil 40 from the power transmission coil being blocked by the components of the tire 10 including a magnetic material existing between these two coils even when a metal belt cord is used for the belt 20 shown in FIG. 1.

[0032] Specifically, the inventor has earnestly studied at what position the power receiving coil 40 provided on the inner side in the tire width direction of the inner cavity surface of the tire 10 should be formed with respect to the power transmission coil (not shown) provided outside the tire 10.

[0033] Furthermore, the inventor has earnestly studied the range of the relative permittivity of the members of the tread portion D, excluding the members of the tread portion D, arranged in the tire radial region WH from the outermost position in the tire radial direction of the bead core 14 to the innermost position in the tire radial direction of the belt 20.

[0034] First, the inventor focused on a plurality of line segments that reach each point (end point) on the outer surface of the tire from each point (starting point) on the inner cavity surface of the tire at the shortest distance in FIG. 1, and extracted a region composed of a plurality of line segments that do not include the belt 20 among these line segments. By providing the power receiving coil 40 so as not to deviate from the inner cavity surface of the tire included in this region, the inventor obtained the finding that most of the magnetic field generated between the two coils is not blocked by the belt 20 that may contain a magnetic material.

[0035] Next, in view of the above finding that it is a finding for defining the outer end in the tire radial direction of the installation region of the power receiving coil 40, the inventor also intensively studied how to define the inner end in the tire radial direction of this installation region. As a result, the inventor focused on the bead core 14 that may be composed of a metal member, extracted a region composed of a plurality of line segments that do not include the bead core 14 among the above line segments, and provided the power receiving coil 40 so as not to deviate from the inner cavity surface of the tire included in this region. Thus, the inventor also obtained the finding that most of the magnetic field generated between the two coils is not blocked by the bead core 14 that may contain a magnetic material.

[0036] Then, by providing the power receiving coil 40 as described above, the inventor obtained the finding that when power is supplied by electromagnetic induction from the outside of the tire 10, it is possible to cope with both power supply modes from the outside in the tire width direction (the direction of arrow a1 in FIG. 1) and from the outside in the tire radial direction (the direction of arrow a2 in FIG. 1). At the same time, the inventor obtained the finding that it is possible to minimize the influence of ferromagnetic substances in the belt 20, the bead portion A, etc. and achieve high transmission efficiency. Here, the ferromagnetic substance mainly means iron (steel material). For example, the ferromagnetic substance in the bead portion A is the steel cord of the bead core 14 (including the steel reinforcement 19 in the configuration example of FIG. 4), and the ferromagnetic substance in the belt 20 is a magnetic material such as the steel cord constituting the belt 20.

[0037] Furthermore, the inventor of the present invention focused on the relative permittivity of the members disposed in the vicinity of the power receiving coil 40, and found that the relative permittivity of the members disposed in the tire radial direction region WH from the outermost position in the tire radial direction of the bead core 14 to the innermost position in the tire radial direction of the belt 20, excluding the tread portion D, affects the transmission efficiency of wireless power transmission from the power transmission coil to the power receiving coil 40. Here, the members include members such as the inner liner 12, the bead filler 16, the carcass 18, the rim cushion 24, the second filler 25, the side tread 26, the wing tip 28, the run-flat liner 32, and the like.

[0038] More specifically, the inventor of the present invention found that if the relative permittivity of these members is too high, the attenuation of electromagnetic waves increases during power transmission and the transmission efficiency decreases. On the other hand, as a result of reducing the carbon content or the like, the inventor found that if the relative permittivity of these members is too low, it becomes difficult to formulate to maintain the original rubber physical properties of these members, and it becomes difficult to satisfy the desired tire performance. The relative permittivity of the carcass 18 is a value including fiber cords and the like as reinforcing materials.

[0039] Based on the above findings, in the tire 10 according to the present embodiment, the power receiving coil 40 is provided in the tire radial direction region WH from the outermost position in the tire radial direction of the bead core 14 to the innermost position in the tire radial direction of the belt 20. Thus, according to the tire 10 according to the present embodiment, since there are no excessive components of the tire 10 that may contain a magnetic material between the power transmission coil and the power receiving coil 40, the power supply efficiency can be improved.

[0040] Further, based on the above findings, in the tire 10 according to the present embodiment, the relative permittivity of the members other than the tread portion D disposed in the tire radial region WH from the outermost position in the tire radial direction of the bead core 14 to the innermost position in the tire radial direction of the belt 20 is 3.5 or more and 250 or less. Here, it is more preferable that the relative permittivity is 4.0 or more and 240 or less, and it is extremely preferable that the relative permittivity is 4.5 or more and 230 or less. The relative permittivity is determined by the polymer structure and compounding agents of the member. The relative permittivity is a measured value at 10 MHz. Further, preferably, the dielectric loss tangent (tan δ) of these members is 0.02 to 1.6.

[0041] The relative permittivity and the dielectric loss tangent (tan δ) are values measured at 10 MHz at 23°C. More specifically, the relative permittivity and the dielectric loss tangent (tan δ) are obtained by preparing a sheet-like sample of a certain thickness using a member cut out from the tire 10, and in an environment of 23°C, using an HP 4291B RF impedance / material analyzer manufactured by Hewlett Packard as an impedance analyzer and a 16453A dielectric material test fixture manufactured by Hewlett Packard as a test fixture, and applying an alternating voltage. They are the measured values of the relative permittivity and the dielectric loss tangent (tan δ) at a frequency of 10 MHz.

[0042] (Additional Form 2) In Basic Form 1, when the magnetic field passes through the tire radial region WH, it passes through the inner liner 12 and the carcass 18. Therefore, the relative permittivity of the inner liner 12 and the carcass 18 has a great influence on the magnetic field of the wireless power supply and a great influence on the transmission efficiency. Further, the inner liner 12 and the carcass 18 are assumed to be disposed closer to the power receiving coil 40 than other members, although the thickness in the tire width direction is relatively thinner than other members, and thus have a greater influence on the magnetic field of the wireless power supply than other members.

[0043] If the relative permittivity of the inner liner 12 and the carcass 18 is too high, the attenuation of the electromagnetic wave for power transmission increases, and the transmission efficiency decreases. On the other hand, if the relative permittivity of the inner liner 12 and the carcass 18 is too low, it becomes difficult to formulate for maintaining the original rubber physical properties of these members, and it becomes difficult to satisfy the desired tire performance.

[0044] Therefore, in the basic form 1, it is preferable that the relative permittivity of the inner liner 12 is in the range of 8 or more and 90 or less, and the relative permittivity of the carcass 18 is in the range of 4 or more and 20 or less (Additional form 2).

[0045] Since the inner liner 12 includes an air barrier layer and an adhesive rubber layer, the relative permittivity of the inner liner 12 is a value of the entire member including the air barrier layer and the adhesive rubber layer. The relative permittivity of the inner liner 12 is more preferably 8.5 or more and 85 or less, and extremely preferably 9 or more and 80 or less.

[0046] Further, since the carcass 18 includes reinforcing fibers, the relative permittivity of the carcass 18 is a value of the entire member including fiber cords and the like as a reinforcing material. The relative permittivity of the carcass 18 is more preferably 4.5 or more and 18 or less, and extremely preferably 5 or more and 16 or less. Also, preferably, the dielectric tangent (tanδ) of the inner liner 12 is 0.06 to 0.80, and more preferably 0.08 to 0.74. Also, preferably, the dielectric tangent (tanδ) of the carcass 18 is 0.06 to 0.16, and more preferably 0.07 to 0.15.

[0047] (Additional form 3) In the basic form 1 or the form in which the additional form 2 is added to the basic form 1, the relative permittivity of the side tread 26 (the rubber material of the side tread 26) is in the range of 3.5 or more and 40 or less, and the relative permittivity of the rim cushion 24 and the bead filler 16 (the rubber material of the rim cushion 24 and the bead filler 16) is in the range of 70 or more and 235 or less (Additional form 3) is preferable.

[0048] The rim cushion 24 and the bead filler 16 are both arranged in the vicinity of the bead portion A, and the required characteristics of the rubber material are generally the same, but are different from the required characteristics of the rubber material for the side tread 26. The side tread 26 is assumed to be arranged closer to the power receiving coil 40 than the rim cushion 24 and the bead filler 16, and is assumed to have a greater influence on the magnetic field of wireless power supply than the rim cushion 24 and the bead filler 16. According to the additional form 3, while maintaining the physical properties (elongation, low heat generation, etc.) required for the side tread 26 and the physical properties (hardness, elastic modulus, etc.) required for the rim cushion 24 and the bead filler 16, the transmission efficiency can be maintained at a high level. The relative permittivity of the side tread 26 is more preferably 4.0 or more and 38 or less, and extremely preferably 4.5 or more and 36 or less. The relative permittivity of the rim cushion 24 and the bead filler 16 is more preferably 75 or more and 230 or less, and extremely preferably 80 or more and 225 or less. Also, preferably, the dielectric loss tangent (tanδ) of the side tread 26 is 0.02 to 0.5, and more preferably 0.03 to 0.45. Also, preferably, the dielectric loss tangent (tanδ) of the rim cushion 24 and the bead filler 16 is 0.6 to 1.5.

[0049] In the case of the tire 10 provided with the second filler 25 as shown in FIG. 3, the relative permittivity of the second filler 25 is preferably the same as that of the bead filler 16. That is, the relative permittivity of the second filler 25 is preferably in the range of 70 or more and 235 or less, more preferably 75 or more and 230 or less, and extremely preferably 80 or more and 225 or less. Also, preferably, the dielectric loss tangent (tanδ) of the second filler 25 is 0.6 to 1.5.

[0050] (Additional form 4) FIG. 5 is a tire meridian cross-sectional view showing the main part of the tire 10 according to the additional form 4. In the basic form 1 or a form in which at least one of the additional forms 2 and 3 is added to the basic form 1, as shown in the figure, the power receiving coil 40 generates electric power by receiving a magnetic field transmitted from a power transmission coil disposed outside the tire in the tire width direction of the power receiving coil 40. In a tire meridian cross-sectional view, a power receiving coil radial region R1 whose length in the tire radial direction is defined by the length between both ends of the power receiving coil 40 in the tire radial direction, and a length in the tire radial direction that is adjacent to both sides of the power receiving coil radial region R1 in the tire radial direction and is defined by 15% of the length in the tire radial direction of the tire radial region WH. In the power receiving vicinity region R2, a side tread 26 having a relative permittivity in the range of 3.5 or more and 37 or less is disposed, and the rim cushion 24 and the bead filler 16 are not disposed. It is preferable that the relative permittivity of the rim cushion 24 and the bead filler 16 disposed inside the power receiving coil radial region R1 and the power receiving vicinity region R2 in the tire radial direction is in the range of 70 or more and 250 or less (additional form 4).

[0051] As shown in FIG. 5, in the tire 10 according to the additional form 4, the entire power receiving coil radial region R1 and the power receiving vicinity region R2 overlap the side tread 26 in the tire radial direction, while not overlapping the rim cushion 24 and the bead filler 16 in the tire radial direction. As shown in FIG. 5, the power receiving coil radial region is a region that extends in the tire width direction and has a length R1 in the tire radial direction in a tire meridian cross-sectional view. Further, the power receiving vicinity region is a region that extends in the tire width direction and has a length R2 in the tire radial direction in a tire meridian cross-sectional view. For convenience of explanation, the power receiving coil radial region will be represented by the symbol R1, and the power receiving vicinity region will be represented by the symbol R2. In the additional form 4, in the positional relationship shown in FIG. 5, the relative permittivity of the side tread 26 is in the range of 3.5 or more and 37 or less, and the relative permittivity of the rim cushion 24 and the bead filler 16 is in the range of 70 or more and 250 or less.

[0052] According to Additional Form 4, by installing the power receiving coil 40 while avoiding the tire diameter direction positions of the rim cushion 24 and the bead filler 16 having a relatively high relative permittivity, high transmission efficiency can be achieved, and the influence of the physical properties of the rim cushion 24 and the bead filler 16 on the transmission efficiency can be suppressed. Therefore, the physical properties of the rim cushion 24 and the bead filler 16 can be set within a range suitable for tire performance. For this reason, the relative permittivity of the rim cushion 24 and the bead filler 16 is allowed to be a higher value than that in Additional Form 3, but the relative permittivity of the side tread 26 is kept lower than that in Additional Form 3 because its influence on the transmission efficiency is large. The relative permittivity of the side tread 26 is more preferably 4.0 or more and 35 or less, and extremely preferably 4.5 or more and 33 or less. The relative permittivity of the rim cushion 24 and the bead filler 16 is more preferably 75 or more and 240 or less, and extremely preferably 80 or more and 230 or less. Also, preferably, the dielectric tangent (tanδ) of the side tread 26 is 0.02 to 0.47, and the dielectric tangent (tanδ) of the rim cushion 24 and the bead filler 16 is 0.6 to 1.6.

[0053] In the case of the tire 10 provided with the second filler 25 as shown in FIG. 3, the relative permittivity of the second filler 25 is preferably equivalent to that of the bead filler 16. That is, the relative permittivity of the second filler 25 is preferably in the range of 70 or more and 250 or less, more preferably 75 or more and 240 or less, and extremely preferably 80 or more and 230 or less. Also, preferably, the dielectric tangent (tanδ) of the second filler 25 is 0.6 to 1.6.

[0054] FIG. 6 is a schematic diagram for explaining the power receiving coil radial region R1, and shows a state of the tire 10 viewed from the tire width direction. FIG. 6(A) is an example in which a plurality of power receiving coil elements 40a having a diameter that fits within the tire radial region WH are arranged side by side in the tire circumferential direction, and is an example in which the power receiving coil 40 is composed of a plurality of power receiving coil elements 40a. Further, FIG. 6(B) is an example in which one power receiving coil 40 is configured using the entire circumference in the tire circumferential direction. The tire radial length (=R1) of the power receiving coil radial region R1 is the maximum value of the length occupied by the power receiving coil 40 in the tire radial direction. In both examples of FIG. 6(A) and FIG. 6(B), the power receiving coil radial region R1 is included in the radial region WH.

[0055] (Additional Form 5) FIG. 7 is a tire meridian sectional view showing a main part of the tire 10 according to the additional form 5. In the basic form 1 or a form in which at least one of the additional forms 2 to 3 is added to the basic form 1, as shown in the figure, the power receiving coil 40 receives a magnetic field transmitted from a power transmission coil arranged outside the tire in the tire width direction of the power receiving coil 40 and generates electric power. In a tire meridian sectional view, in the power receiving coil radial region R1 whose tire radial length is defined by the length between both tire radial ends of the power receiving coil 40, a side tread 26 having a relative permittivity in the range of 3.5 or more and 37 or less is arranged, and the rim cushion 24 and the bead filler 16 are not arranged. At least a part of the power receiving vicinity region R2 adjacent to both sides in the tire radial direction with respect to the power receiving coil radial region R1 and having a tire radial length defined by 15% of the tire radial length of the tire radial region WH, at least one of the bead filler 16 and the rim cushion 24 having a relative permittivity in the range of 70 or more and 235 or less is preferably arranged (Additional Form 5).

[0056] As shown in FIG. 7, in the tire 10 according to the additional form 5, the entire area of the power receiving coil radial region R1 overlaps with the side tread 26 in the tire radial direction, and at least a part of the power receiving vicinity region R2 overlaps with at least one of the rim cushion 24 and the bead filler 16 (in the case shown in FIG. 7, the rim cushion 24) in the tire radial direction. At least a part of the power receiving vicinity region R2 may be configured to overlap with both the rim cushion 24 and the bead filler 16 in the tire radial direction. In the additional form 5, in the positional relationship shown in FIG. 7, the relative permittivity of the side tread 26 is in the range of 3.5 or more and 37 or less, and the relative permittivity of the rim cushion 24 and the bead filler 16 is in the range of 70 or more and 235 or less.

[0057] On the inner surface of the tire cavity where the power receiving coil 40 is provided, deformation and release are repeated during the rolling of the tire 10. In order to enhance the durability of the power receiving coil 40 against these deformations, it may be better to bring the power receiving coil 40 closer to the rim cushion 24 or the bead filler 16 on the inner side in the tire radial direction. According to the additional form 5, for reasons such as the durability of the power receiving coil 40, when the power receiving coil 40 has to be installed close to the rim cushion 24 and the bead filler 16, the relative permittivity of at least the rim cushion 24 and the bead filler 16 arranged in the power receiving vicinity region R2 is set within the above range. Thereby, excellent transmission efficiency can be realized by not arranging the rim cushion 24 and the bead filler 16 in the power receiving coil radial region R1, and excellent durability can be realized by setting the physical properties of the rim cushion 24 and the bead filler 16 within a range suitable for tire performance. The relative permittivity of the side tread 26 is more preferably 4.0 or more and 35 or less, and extremely preferably 4.5 or more and 33 or less. The relative permittivity of the rim cushion 24 and the bead filler 16 is more preferably 75 or more and 230 or less, and extremely preferably 80 or more and 225 or less. Also, preferably, the dielectric loss tangent (tanδ) of the side tread 26 is 0.02 to 0.47, and the dielectric loss tangent (tanδ) of the rim cushion 24 and the bead filler 16 is 0.6 to 1.5.

[0058] In the case of the tire 10 provided with the second filler 25 as shown in FIG. 3, it is preferable that the relative permittivity of the second filler 25 is equivalent to that of the bead filler 16. That is, the relative permittivity of the second filler 25 is preferably in the range of 70 or more and 235 or less, more preferably 75 or more and 230 or less, and extremely preferably 80 or more and 225 or less. Further, preferably, the dielectric loss tangent (tan δ) of the second filler 25 is 0.6 to 1.5.

[0059] (Additional Form 6) FIG. 8 is a tire meridian sectional view showing a main part of the tire 10 according to the additional form 6. In the basic form 1 or the form obtained by adding at least any one of the additional forms 2 to 3 to the basic form 1, as shown in the figure, the power receiving coil 40 receives a magnetic field transmitted from a power transmission coil disposed outside the tire in the tire width direction of the power receiving coil 40 and generates electric power. In the power receiving coil radial region R1 defined by the length in the tire radial direction between both end portions in the tire radial direction of the power receiving coil 40 in a tire meridian sectional view, a side tread 26 having a relative permittivity in the range of 3.5 or more and 37 or less is disposed, and at least one of the bead filler 16 and the rim cushion 24 having a relative permittivity in the range of 70 or more and 220 or less is disposed (Additional Form 6), which is preferable.

[0060] As shown in FIG. 8, in the tire 10 according to the additional form 6, the power receiving coil radial region R1 is configured to overlap the side tread 26 in the tire radial direction and at the same time overlap at least one of the rim cushion 24 and the bead filler 16 (in the part shown in FIG. 8, it is the rim cushion 24). The power receiving coil radial region R1 may be configured to overlap both the rim cushion 24 and the bead filler 16 in the tire radial direction. In the additional form 6, in the positional relationship shown in FIG. 8, the relative permittivity of the side tread 26 is in the range of 3.5 or more and 37 or less, and the relative permittivity of the rim cushion 24 and the bead filler 16 is in the range of 70 or more and 220 or less.

[0061] According to Additional Form 6, when at least one of the rim cushion 24 and the bead filler 16 having a relatively high relative permittivity and the side tread 26 having a relatively low relative permittivity are arranged in the power receiving coil radial direction region R1, since the relative permittivity of at least one of the rim cushion 24 and the bead filler 16 predominantly affects the transmission efficiency, by setting the relative permittivities of the rim cushion 24 and the bead filler 16 within the above range, the transmission efficiency required for wireless power supply can be maintained. The relative permittivity of the side tread 26 is more preferably 4.0 or more and 35 or less, and extremely preferably 4.5 or more and 33 or less. The relative permittivities of the rim cushion 24 and the bead filler 16 are more preferably 75 or more and 215 or less, and extremely preferably 80 or more and 210 or less. Also, preferably, the dielectric loss tangent (tanδ) of the side tread 26 is 0.02 to 0.47, and the dielectric loss tangent (tanδ) of the rim cushion 24 and the bead filler 16 is 0.6 to 1.4.

[0062] FIG. 9 is a tire meridian sectional view showing a main part of the tire 10 according to Additional Form 6, showing the case where the tire 10 includes a second filler 25. In this case, the relative permittivity of the second filler 25 is preferably equivalent to that of the bead filler 16. That is, the relative permittivity of the second filler 25 is preferably in the range of 70 or more and 220 or less, more preferably 75 or more and 215, and extremely preferably 80 or more and 210 or less. Also, preferably, the dielectric loss tangent (tanδ) of the second filler 25 is 0.6 to 1.4.

[0063] (Additional Form 7) FIG. 10 is a tire meridian cross-sectional view showing the main part of a tire 10 according to Additional Form 7. In the basic form 1 or a form in which at least any one of Additional Forms 2 to 3 is added to the basic form 1, as shown in the figure, the power receiving coil 40 receives a magnetic field transmitted from a power transmitting coil arranged outside the tire in the tire width direction of the power receiving coil 40 and generates electric power. In the power receiving coil radial region R1 defined by the length in the tire radial direction between both end portions in the tire radial direction of the power receiving coil 40 in a tire meridian cross-sectional view, at least one of a bead filler 16 and a rim cushion 24 having a relative permittivity in the range of 70 or more and 200 or less is arranged, and the side tread 26 is not arranged. It is preferable that the relative permittivity of the side tread 26 arranged outside the power receiving coil radial region R1 in the tire radial direction is in the range of 3.5 or more and 40 or less (Additional Form 7).

[0064] As shown in FIG. 10, in the tire 10 according to Additional Form 7, the power receiving coil radial region R1 is configured to overlap at least one of the bead filler 16 and the rim cushion 24 in the tire radial direction (in the example shown in FIG. 10, both the bead filler 16 and the rim cushion 24), and at the same time not to overlap with the side tread 26. The power receiving coil radial region R1 may be configured to overlap either the rim cushion 24 or the bead filler 16 in the tire radial direction. In Additional Form 7, in the positional relationship shown in FIG. 10, the relative permittivity of the rim cushion 24 and the bead filler 16 is in the range of 70 or more and 200 or less, and the relative permittivity of the side tread 26 is in the range of 3.5 or more and 40 or less.

[0065] According to Additional Embodiment 7, when at least only one of the rim cushion 24 and the bead filler 16 having a relatively high relative permittivity is disposed in the power receiving coil radial direction region R1 and the side tread 26 is not disposed, by setting the relative permittivity of the rim cushion 24 and the bead filler 16 within the above range, the transmission efficiency required for wireless power supply can be maintained. The relative permittivity of the rim cushion 24 and the bead filler 16 is more preferably 75 or more and 195 or less, and extremely preferably 80 or more and 190 or less. The relative permittivity of the side tread 26 is more preferably 4.0 or more and 38 or less, and extremely preferably 4.5 or more and 36 or less. Further, preferably, the dielectric loss tangent (tanδ) of the rim cushion 24 and the bead filler 16 is 0.6 to 1.3, and the dielectric loss tangent (tanδ) of the side tread 26 is 0.02 to 0.50.

[0066] In the case of the tire 10 provided with the second filler 25 as shown in FIG. 3, the relative permittivity of the second filler 25 is preferably equivalent to that of the bead filler 16. That is, the relative permittivity of the second filler 25 is preferably in the range of 70 or more and 200 or less, more preferably 75 or more and 195 or less, and extremely preferably 80 or more and 190 or less. Further, preferably, the dielectric loss tangent (tanδ) of the second filler 25 is 0.6 to 1.3.

[0067] (Additional Embodiment 8) In the basic form 1 or the form obtained by adding at least any one of the additional forms 2 to 7 to the basic form 1, it is preferable that the difference in relative permittivity between each member disposed in the tire radial direction region WH and another member adjacent in the tire width direction is 170 or less (Additional Embodiment 8).

[0068] For example, along the chain double-dashed line I-I' shown in FIG. 1, an inner liner 12, a carcass 18, a side tread 26, and a wing tip 28 are arranged adjacent to each other in order from the inner side in the tire width direction. Also, along the chain double-dashed line II-II' shown in FIG. 1, an inner liner 12, a carcass 18, and a side tread 26 are arranged adjacent to each other in order from the inner side in the tire width direction. Further, along the chain double-dashed line III-III' shown in FIG. 1, an inner liner 12, a carcass 18, a rim cushion 24, and a side tread 26 are arranged adjacent to each other in order from the inner side in the tire width direction. Also, along the chain double-dashed line IV-IV' shown in FIG. 3, an inner liner 12, a main body portion 18a of the carcass 18, a bead filler 16, a folded-back portion 18b of the carcass 18, a second filler 25, a rim cushion 24, and a side tread 26 are arranged adjacent to each other in order from the inner side of the tire. The difference in relative permittivity between any two adjacent members is 170 or less. More specifically, considering all combinations including the configuration having the run-flat liner 32 shown in FIG. 2, the difference in relative permittivity between adjacent members can be represented by the following inequality. Here, let the relative permittivity of the inner liner 12 be IL, the relative permittivity of the carcass 18 be C, the relative permittivity of the side tread 26 be ST, the relative permittivity of the wing tip 28 be WT, the relative permittivity of the second filler 25 be 2FL, the relative permittivity of the bead filler 16 be BFL, the relative permittivity of the rim cushion 24 be RC, and the relative permittivity of the run-flat liner 32 be RFL. The relative permittivity of the inner liner 12 is the value of the entire member including the air barrier layer and the adhesive rubber layer. Also, the relative permittivity of the carcass 18 is the value of the entire member including the reinforcing fibers. The relative permittivity of the other members is the relative permittivity of the rubber layer of the member. |IL - C| ≤ 170 |ST - C| ≤ 170 |ST - WT| ≤ 170 |RC - C| ≤ 170 |RC - ST| ≤ 170 |C - BFL| ≤ 170 |C - 2FL| ≤ 170 |ST - 2FL| ≤ 170 |RC - 2FL| ≤ 170 |IL - RFL| ≤ 170 |C-RFL| ≤ 170

[0069] When the difference in relative permittivity between adjacent members is large at the interface between the adjacent members, the high-frequency magnetic field is reflected and the transmission efficiency decreases. However, according to Additional Form 8, since the difference in relative permittivity between adjacent members is 170 or less, reflection of the high-frequency magnetic field can be suppressed and a decrease in transmission efficiency can be suppressed. More specifically, even when the difference in relative permittivity between adjacent members is 170 or less, high-frequency electromagnetic waves are reflected at the interface between the adjacent members. In that case, however, the loss due to eddy currents generated in the bead portion A of the tire 10 or the metal of the belt 20 is larger, so the reflection of the high-frequency electromagnetic waves does not pose a problem relatively. Therefore, by making the difference in relative permittivity between adjacent members 170 or less, it is possible to limit it to only the eddy current loss in the bead portion A and the belt 20. Further, when all members in the tire radial direction region WH satisfy the above range, the degree of freedom in the position where the power receiving coil 40 is disposed is increased. The difference in relative permittivity between adjacent members is more preferably 160 or less, and extremely preferably 150 or less. Also, preferably, the difference in dielectric tangent (tan δ) of the relative permittivity between adjacent members is 0.9 or less.

[0070] (Additional Form 9) In Basic Form 1 or a form in which at least one of Additional Forms 2 to 8 is added to Basic Form 1, the power receiving coil 40 receives the magnetic field transmitted from the power transmission coil disposed outside the tire in the tire width direction of the power receiving coil 40 and generates electric power. In a tire meridian cross-sectional view, for a member disposed in the power receiving coil radial direction region R1 whose length in the tire radial direction is defined by the length between both ends in the tire radial direction of the power receiving coil, it is preferable that the difference in relative permittivity from another member adjacent in the tire width direction is 165 or less (Additional Form 9).

[0071] The members arranged in the radial region R1 of the power receiving coil have a particularly large impact on the power transmission efficiency. Therefore, compared with the members arranged outside the radial region R1 of the power receiving coil in the tire radial direction, it is preferable to make the difference in relative permittivity between adjacent members smaller. Thus, it is preferable to satisfy the above range. The difference in relative permittivity between adjacent members is more preferably 155 or less, and extremely preferably 150 or less. Also, preferably, the difference in dielectric loss tangent (tanδ) of the relative permittivity of adjacent rubber layers is 0.88 or less.

[0072] (Additional Form 10) In the basic form 1 or the form obtained by adding at least any one of additional forms 2 to 9 to the basic form 1, the conductive wire 43 of the power receiving coil 40 is installed on the surface of the inner liner 12 that constitutes the tire inner cavity surface via the support layer 44, and in the tire radial region WH, the relative permittivity of the support layer 44 existing between the conductive wire 43 and the inner liner 12 is preferably lower than the relative permittivity of the inner liner 12 (Additional Form 10).

[0073] FIG. 11 is a tire meridian sectional view showing the main part of the tire 10 according to the additional form 10, and is an enlarged view of the power receiving coil 40 installed on the surface of the inner liner 12 that constitutes the tire inner cavity surface via the support layer 44 and its periphery. FIG. 11(A) shows an example in which the conductive wire 43 of the power receiving coil 40 is installed on the surface of the inner liner 12 via an insulating support layer 44, and the conductive wire 43 is exposed in the tire inner cavity. FIG. 11(B) shows an example in which the conductive wire 43 of the power receiving coil 40 is installed on the surface of the inner liner 12 via the support layer 44, and the conductive wire 43 is covered with the support layer 44. FIG. 11(C) shows an example in which the conductive wire 43 of the power receiving coil 40 is installed on the surface of the inner liner 12 via the support layer 44, and the conductive wire 43 is covered with a layer 46 different from the support layer 44.

[0074] In any of FIGS. 11(A) to 11(C), a support layer 44 is interposed between the conductive wire 43 and the inner liner 12, and the conductive wire 43 and the inner liner 12 are not in contact. An electric current due to magnetic resonance flows through the conductive wire 43, thereby generating a magnetic field around the conductive wire 43. The closer to the conductive wire 43, the greater the magnetic flux density, and the greater the influence of the relative permittivity of the member closer to the conductive wire 43 on the attenuation of the magnetic field. According to the additional form 10, by separating the inner liner 12 from the conductive wire 43 and installing a support layer 44 having a low relative permittivity between the inner liner 12 and the conductive wire 43, the attenuation of the magnetic field can be suppressed. The support layer 44 and another layer 46 are made of an insulator and may be, for example, rubber, resin, or the like.

[0075] (Additional form 11) FIG. 12 is a tire meridian sectional view showing a main part of the tire 10 according to the additional form 11, and is a view showing an enlarged view of the power receiving coil 40 installed on the surface of the inner liner 12 in the tire inner cavity via the support layer 44 and its periphery. FIG. 12(A) shows an example in which, similar to FIG. 11(A), the conductive wire 43 of the power receiving coil 40 is installed on the surface of the inner liner 12 via an insulating support layer 44, and the conductive wire 43 is exposed in the tire inner cavity. FIG. 12(B) shows an example in which the support layer 44 is embedded in the inner liner 12. Dmin in formula (1) is the shortest distance from the conductive wire 43 of the power receiving coil 40 to the inner liner 12 shown in FIGS. 12(A) and 12(B).

[0076] In the basic form 1 or the form obtained by adding at least any one of the additional forms 2 to 10 to the basic form 1, the power receiving coil 40 receives a magnetic field transmitted from a power transmitting coil arranged outside the tire in the tire width direction of the power receiving coil 40 to generate electric power. In a tire meridian sectional view, the relative permittivity εr of each member on an imaginary line in the tire width direction at an arbitrary position within the power receiving coil radial direction region R1 k and the thickness G in the tire width direction kThe sum of the products of (mm) and (k = 1 to n (n is the number of members on the virtual line)), and the relationship between the shortest distance Dmin from the conductive wire 43 of the power receiving coil 40 to the inner liner 12 being within the range of Expression (1) (Additional Form 11) is preferable. The relative permittivity of the inner liner 12 is a value for the entire member including the air barrier layer and the adhesive rubber layer. Also, the relative permittivity of the carcass 18 is a value for the entire member including fiber cords as a reinforcing material, etc. The thicknesses of the inner liner 12 and the carcass 18 are the thicknesses of the members themselves.

[0077]

Number

[0078] The inventor first considered the relative permittivity εr of each member on the above virtual line k and the product of the thickness G in the tire width direction k (mm), and found that the larger the sum of the products, the more the magnetic field decays. Also, as described above, a current due to magnetic field resonance flows through the conductive wire 43, and the closer to the conductive wire 43, the greater the magnetic flux density, and the greater the influence of the relative permittivity of the support layer 44 close to the conductive wire 43 on the attenuation of the magnetic field. For this reason, the inventor found the relationship of Expression (1) based on the finding that if the thickness (shortest distance Dmin) of the support layer 44 is small, even if the sum of the product of the relative permittivity εr of each member k and the thickness G in the tire width direction k (mm) is relatively large, the attenuation of the magnetic field is suppressed.

[0079] According to Additional Form 11, it is possible to suppress the attenuation of the magnetic field passing through the tire 10, suppress the loss of the magnetic field formed around the conductive wire 43, and maintain high transmission efficiency. If the value of Σ / Dmin in Expression (1) is less than 200, the shortest distance Dmin becomes excessive, the support layer 44 becomes thick, increasing the tire mass, or the thickness G of each member k is too small to appropriately obtain the rigidity of the tire 10. Also, if the value of Σ / Dmin is greater than 6000, the shortest distance Dmin is too small, the inner liner 12 and the conductive wire 43 approach each other, the attenuation of the magnetic field increases, or the thickness G of each member kis too large, resulting in a large attenuation of the magnetic field. Therefore, it is preferable to satisfy the range of formula (1). The relative permittivity εr of each member k and the thickness G in the tire width direction k (mm) is preferably 250 or more and 5500 or less, and extremely preferably 300 or more and 5000 or less, when divided by the shortest distance Dmin.

[0080] (Additional form 12) In the basic form 1 or the form obtained by adding at least any one of the additional forms 2 to 11 to the basic form 1, as shown in FIG. 2, a side support layer (run-flat liner 32) is provided inside the tire width direction of the carcass 18, and the relative permittivity of the side support layer (rubber material) is in the range of 8 to 90, and it is preferable that the relative permittivity of the side support layer is lower than the higher relative permittivity of the rim cushion 24 and the bead filler 16 (rubber material) (Additional form 12).

[0081] Additional form 12 corresponds to the configuration shown in FIG. 2. Since the run-flat liner 32 is arranged over the tire radial direction region WH, the power receiving coil 40 is arranged close to the run-flat liner 32. The greater the thickness t of the run-flat liner 32, the greater the influence on the attenuation of the magnetic field. According to the additional form 12, the rubber layers arranged around the power receiving coil 40 are the inner liner 12, the carcass 18, and the run-flat liner 32, and the power receiving coil 40 is separated from the rim cushion 24 and the bead filler 16. Therefore, if the relative permittivity of the run-flat liner 32 is lower than the higher relative permittivity of the rim cushion 24 and the bead filler 16, the sidewall portion B becomes thicker due to the run-flat liner 32, and the degree of attenuation of the magnetic field caused thereby can be alleviated. The relative permittivity of the rubber material constituting the run-flat liner 32 is more preferably in the range of 8.5 to 85, and extremely preferably 9 to 80 or less. Also, preferably, the difference in the dielectric tangent (tanδ) of the run-flat liner 32 is 0.06 or more and 0.8 or less.

[0082] (Additional form 13) In the additional aspect 12, for example, in the tire meridian cross-sectional view shown in FIG. 2, in the power receiving coil radial region R1 where the length in the tire radial direction is defined by the length between both end portions in the tire radial direction of the power receiving coil 40, it is preferable that the maximum value of the tire width direction thickness t of the side support layer (run-flat liner 32) is in the range of 4 to 12 mm (additional aspect 13). When the thickness t of the run-flat liner 32 is greater than 12 mm, the heat generation of the run-flat liner 32 during running increases, which hinders the heat dissipation of the power receiving coil 40. When the thickness t of the run-flat liner 32 is greater than 12 mm, the influence on the attenuation of the magnetic field increases. Also, by setting the thickness t of the run-flat liner 32 to 4 mm or more, the power receiving coil 40 can be separated from the rim cushion 24 and the bead filler 16 having a higher relative permittivity, thereby reducing the influence on the transmission efficiency and achieving compatibility with the run-flat performance. Therefore, it is preferable that the maximum value of the tire width direction thickness t of the run-flat liner 32 is in the range of 4 to 12 mm. More preferably, the maximum value of the tire width direction thickness t of the run-flat liner 32 is in the range of 4.5 to 11.5, and extremely preferably 5 to 11 or less. Also, preferably, the dielectric loss tangent (tanδ) of the run-flat liner 32 is 0.06 to 0.8.

[0083] <Wireless power supply system> [Basic aspect 14] FIG. 13 is a view showing a wireless power supply system 50 according to the present embodiment, a power transmission coil 52, and a tire 10 provided with a power receiving coil 40 (on one side in the tire width direction with respect to the tire equatorial plane CP in the tire meridian cross-sectional view). In the figure, the tire portion on the side opposite to the ground contact surface is shown in a state where the rim is assembled and the normal internal pressure is applied, and a load of 80% of the normal load is applied (hereinafter, the same applies to the invention of the wireless power supply system). The power transmission coil 52 shown in the figure is a coil wound around the tire width direction as the winding axis. In particular, for the portion extending in the tire radial direction, it may extend only in the tire radial direction, or may also extend in at least one of the other tire circumferential direction and the tire width direction in addition to the tire radial direction.

[0084] The power transmission coil 52 shown in the figure forms a resonant circuit with a capacitor and a coil, and is attached to the surface on the tire side of a knuckle, which is a component of the steering axle of a vehicle (not shown in the figure), for example.

[0085] On the other hand, the power receiving coil 40 shown in FIG. 13 has the same configuration as the power receiving coil shown in FIG. 1, and forms a resonant circuit with a capacitor and a coil. The tire 10 shown in FIG. 13 is a tire of the basic form 1 related to the above-described tire 10 and a tire to which at least one of the additional forms 2 to 13 is added, and its operation, function, etc. are as described above.

[0086] Under such a premise, the wireless power supply system 50 according to the present embodiment is a wireless power supply using a magnetic field resonance method using an alternating magnetic field. As shown in FIG. 13, power is supplied to the power transmission coil 52, and power is transmitted to the power receiving coil 40 by the alternating magnetic field. According to such a wireless power supply system 50, as described above, the power supply efficiency can be improved.

[0087] Here, in order to drive the sensors and associated electric circuits installed in the tire 10, it is preferable to transmit power of 0.1 to 15 W at a frequency of 1 to 20 MHz. More preferably, the power transmission coil 52 is supplied with alternating current power having a frequency of 6.78 to 13.56 MHz.

[0088] Also, the shortest distance between the power transmission coil 52 and the power receiving coil 40 (hereinafter, may be referred to as "transmission gap G") is preferably 10 mm or more and 80 mm or less. Here, the transmission gap G is a value measured in a state where the tire 10 is rim-mounted, normal internal pressure is applied, and the vehicle is attached and stopped on flat ground. Also, in FIG. 13, the transmission gap G is the shortest distance between the power transmission coil 52 and the power receiving coil 40, that is, in FIG. 13, the distance between the innermost position in the tire width direction of the power transmission coil 52 and the outermost position in the tire width direction of the power receiving coil 40.

[0089] By setting the transmission gap G to 10 mm or more, it is possible to suppress an excessive change rate of the received power due to the change in the relative position between the power transmission coil 52 and the power reception coil 40 shown in FIG. 13 in the power transmission direction. The circuit configuration connected to the power reception coil 40 can be made simple, and thus stable power can be easily supplied to the electronic device. Here, the change in the received power depends on the fact that during the rolling of the tire 10, the tire 10 expands slightly due to centrifugal force, causing the relative position between the two coils 52 and 40 to change. Specifically, the higher the tire rolling speed, the more the tire 10 expands in the tire radial direction, causing the power reception coil 40 to move outward in the tire radial direction (the upper side in FIG. 13), while the position of the power transmission coil 52 remains unchanged, so the relative position between the two coils 52 and 40 changes.

[0090] On the other hand, by setting the transmission gap G to 80 mm or less, the strength of the magnetic field generated between the two coils 52 and 40 does not become excessively small, and power feeding by electromagnetic induction can be efficiently performed.

[0091] It is more preferable that the transmission gap G is 12 mm or more and 75 mm or less, and extremely preferably 15 mm or more and 70 mm or less.

[0092] By adopting the above range of the transmission gap G, power range, and frequency band, not only can the temperature rise of the power reception coil 40 be suppressed, but also an increase in the number of turns of the coil etc. (and thus an increase in coil weight) is not required, the rolling resistance of the tire is not increased, power feeding can be efficiently performed, and thus excellent transmission efficiency can be realized. In particular, according to the above-described range of the transmission gap G, excellent power feeding efficiency can be obtained when power is transmitted using the tire structure in the wireless power feeding of the magnetic field resonance method in the above frequency band.

[0093] [Additional Form 15] FIG. 14 is a diagram showing an overlapping pattern between the tire radial position of the power transmission coil 52 and the tire radial position of the power reception coil 40 for the wireless power supply system 50 according to the present embodiment. (A) shows an example in which the outer portion of the power transmission coil 52 in the tire radial direction overlaps with the inner portion of the power reception coil 40 in the tire radial direction, and (B) shows an example in which the inner portion of the power transmission coil 52 in the tire radial direction overlaps with the outer portion of the power reception coil 40 in the tire radial direction.

[0094] In the basic form 14, as shown in FIGS. 14(A) and (B), in the tire meridian cross-sectional view, it is preferable that at least a part of the power reception coil 40 is located within the power supply region extending in the winding axis direction of the power transmission coil 52 between both longitudinal ends of the power transmission coil 52 (additional form 15). Here, the positional relationship between the power reception coil 40 and the power transmission coil 52 in the tire radial direction is measured in a state where the tire 10 is rim-mounted, a normal internal pressure is applied, and the vehicle is attached and stopped on a flat ground.

[0095] In the wireless power supply system 50 according to the present embodiment, the power transmission coil 52 is attached to a knuckle or a hub carrier (located on the outer side in the tire width direction of the sidewall portion B), which is a component of the steering axle of the vehicle, or the tire-side surface of any component constituting the strut structure. Therefore, when considering the power supply efficiency in view of the shape of the sidewall portion B of the tire 10 in particular, as shown in FIGS. 14(A) and (B), it is desirable that the direction of the magnetic field lines penetrating the tire in the sidewall portion B, and thus the power supply direction Dp, be substantially in the tire width direction.

[0096] In accordance with such findings, as shown in FIGS. 14(A) and (B), when the power supply direction Dp is substantially in the tire width direction, power supply can be performed more efficiently, and thus excellent transmission efficiency can be realized.

[0097] Also, in the examples shown in FIGS. 14(B) and 14(C), for each of the power transmission coil 52 and the power reception coil 40, since the constituent planes (the planes perpendicular to the winding axes of the respective coils in FIGS. 14(B) and 14(C)) are parallel to each other, compared with the examples shown in FIGS. 14(A) and 14(D), power supply can be performed more efficiently, and thus excellent transmission efficiency can be realized.

[0098] Note that, as shown in FIGS. 14(A) and 14(D), the power transmission coil 50 and the power reception coil 40 do not necessarily have their constituent planes parallel to each other. The reason is that if the magnetic field generated by the power transmission coil 52 links with the power reception coil 40, an electromotive force is generated by electromagnetic induction, and there is no constraint on the relative orientation of the above-mentioned planes.

[0099] [Additional Form 16] FIG. 15 is a diagram showing the installation position of the power transmission coil 52 with respect to the wireless power supply system 50 according to the present embodiment.

[0100] In the basic form 14 or the form obtained by adding the additional form 15 to the basic form 14, as shown in FIG. 15, it is preferable that the power transmission coil 52 is installed within a range of 60° on both sides in the tire circumferential direction centered on an imaginary line extending vertically upward from the tire center O (additional form 16).

[0101] Generally, when the tire 10 rolls, the power receiving coil 40 deforms along with the deformation at the ground contact portion of the tire 10, while hardly any deformation of the power receiving coil 40 due to tire deformation is observed at the portion away from the ground contact portion of the tire 10 (the upper part of the tire 10 in FIG. 15). Therefore, by installing the power transmission coil 52 disposed outside the tire 10 near the upper part of the tire away from the installation portion of the tire 10 (the tire circumferential direction range of 60° on both sides of the virtual line extending vertically upward from the tire center O), it is possible to suppress the variation of the above-described transmission gap G during tire rolling, perform power supply more efficiently, and thus realize even better transmission efficiency. Note that the example shown in FIG. 15 is an example of attaching the power transmission coil 52 to the wheel house 54, and the above-described tire circumferential direction range is applied within the wheel house 54.

[0102] In addition, it is more preferable that the power transmission coil 52 is installed in the tire circumferential direction range of 55° on both sides of the virtual line extending vertically upward from the tire center, and it is extremely preferable that the power transmission coil 52 is installed in the tire circumferential direction range of 50° on both sides of the virtual line.

[0103] Also, the shape of the power transmission coil 52 is not particularly limited, but when the power transmission coil 52 is installed in the wheel house, for example, it is preferable to use a so-called spiral coil that can reduce the thickness as a whole.

[0104] [Additional Form 17] FIGS. 16 and 17 are diagrams showing the positions where the power transmission coil is installed in the tire shown in FIG. 1.

[0105] In the form in which at least any one of Additional Forms 15 and 16 is added to Basic Form 14 or Basic Form 14, it is preferable that the power transmission coil 52 is installed on the spring lower member of the vehicle (Additional Form 17).

[0106] The spring lower member includes, for example, a knuckle, a brake caliper, and a damper case of a strut suspension. By providing the power transmission coil 52 on the spring lower member, even when the vehicle moves up and down due to unevenness of the road surface, the distance between the power transmission coil 52 and the power reception coil 40 provided on the tire 10 can be kept constant.

[0107] As shown in FIGS. 16(A) and 16(B), the power transmission coil 52 may be provided in the damper case 60 of the strut suspension. FIG. 16(A) shows an example in which the power transmission coil 52 is provided in the damper case 60 of the front wheel, and FIG. 16(B) shows an example in which the power transmission coil 52 is provided in the damper case 60 of the rear wheel. Thereby, even when the tire 10 moves up and down due to unevenness of the road surface, the power transmission coil 52 faces the power reception coil 40 in the tire width direction, avoids the belt and the bead core, and can transmit power in the tire width direction. Therefore, the wireless power supply system 50 can improve the power supply efficiency.

[0108] Further, the power transmission coil 52 may be provided on a member that moves together with the tire 10 in conjunction with steering, such as a knuckle of a multi-link type suspension. FIG. 17 shows a front wheel of a multi-link type suspension, and the knuckle 70 rolls together with the tire 10 with respect to the upper arm 72 in conjunction with steering. Thereby, even during steering, the distance between the power transmission coil 52 and the power reception coil 40 provided on the tire 10 can be kept constant. Therefore, the tire 10 can be stably supplied with power during traveling.

[0109] <Other embodiments of the tire and the wireless power supply system> The above is the description of the tire and the wireless power supply system according to the present invention. Hereinafter, other matters regarding the tire and the wireless power supply system according to the present invention will be listed.

[0110] The carbon content of the inner liner 12, which is a component of the tire 10 shown in FIG. 1, is 45 to 75 parts by weight (parts by weight when the rubber is 100, the same hereinafter), the carbon content of the side tread is 25 to 65 parts by weight, the carbon content of the rim cushion is 60 to 90 parts by weight, the carbon content of the bead filler 16 is 40 to 80 parts by weight, the carbon content of the covering rubber of the carcass 18 is 35 to 70 parts by weight, and the carbon content of the run-flat liner is preferably 45 to 75 parts by weight. By adopting these respective compounding amounts, while realizing a desired relative permittivity in each rubber layer, each performance of the tire described above can be realized. Note that usually, the relative permittivity of rubber is determined by the polymer type and compounding agent, and it is most preferable to adjust the carbon content because it is easy to change the electrical properties (since carbon particles themselves have high conductivity) and it is easy to balance with the properties of the rubber required for the tire.

[0111] Regarding the wireless power supply system 50 shown in FIG. 13, the power receiving coil 40 is preferably provided in the tire inner cavity of the sidewall portion B of the tire 10 such that the power receiving surface faces in the tire width direction. As described above, as shown in FIGS. 14(a) and (b), when the transmission direction by the power transmission coil 52 is substantially in the tire width direction, by providing the power receiving coil 40 such that its power receiving surface faces in the tire width direction, the power transmission surface of the power transmission coil 52 and the power receiving surface of the power receiving coil 40 become parallel. Thereby, power supply can be performed more efficiently, and thus excellent transmission efficiency can be realized.

[0112] FIG. 18 is a view showing an arrangement mode of the power receiving coil 40 (a mode in which the power receiving coil 40 is not continuous in the tire circumferential direction, the same as in FIG. 6(A)), and (A) to (F) are examples showing the power receiving coil 40 composed of 2 sets, 3 sets, 4 sets, 5 sets, 6 sets, and 8 sets of power receiving coil elements 40a respectively, (G) is an example in which a plurality of power receiving coil elements 40a are laminated in the tire radial direction, and (H) is an example in which a part of a plurality of power receiving coil elements 40a extends obliquely with respect to the tire radial direction.

[0113] As shown in FIGS. 18(A) to (H), the power receiving coil 40 may be formed of a plurality of power receiving coil elements 40a. On the inner surface of the tire cavity where the power receiving coil 40 is provided, during the rolling of the tire 10, the deformation and release of the tire 10 are repeated. When one power receiving coil 40 is provided around the entire circumference of the tire 10, this power receiving coil 40 has a portion that is deformed and distorted (near the grounding portion of the tire 10) and a portion that is not deformed (the upper portion of the tire 10) during the rolling of the tire 10, and the power receiving coil 40 is likely to peel off from the inner surface of the tire cavity. Therefore, by dividing the tire circumference into a plurality of regions and arranging the power receiving coil elements 40a in each of the divided regions, it is possible to suppress the peeling of the power receiving coil 40 from the inner peripheral surface of the tire.

[0114] FIG. 19 is a tire meridian cross-sectional view (however, half in the tire width direction) showing a power supply mode for supplying power from the power receiving coil 40 to the electronic device 46 attached to the inner surface of the tire cavity via the power line 44 in the tire 10 shown in FIG. 1.

[0115] According to what is shown in the figure, the power receiving coil 40 is connected to a capacitor (not shown) as a resonance circuit, and further supplies power to an electronic device 46 (sensor, signal processing circuit, communication corridor, etc.) attached to the inner surface of the tire cavity via the power line 44 attached to the inner surface of the tire cavity. The electronic device 46 has lower durability against deformation than the power receiving coil 40, and on the other hand, even if it is installed near the belt 20 which is a magnetic body, there is no problem due to the influence of the magnetic field. For this reason, the electronic device 46 is arranged on the inner surface of the tire cavity in the tire width direction region where the belt 20 having high rigidity is formed in the tire 10, the power receiving coil 40 is arranged on the inner surface of the tire cavity of the sidewall portion B where the power supply efficiency can be increased, and the two are wired-connected by the power line 44. Thereby, the power received by the power receiving coil 40 can be supplied to the electronic device 46 with less loss and high power supply efficiency, and at the same time, the durability of the electronic device 46 can be ensured. Further, by arranging all these components (power receiving coil 40, capacitor, power line 44, and electronic device 46) on the inner surface of the tire cavity, an increase in the manufacturing cost and manufacturing difficulty of the tire 10 is suppressed.

Example

[0116] Hereinafter, a comparison of the predetermined effects of the present application among the inventions defined in claims 1 to 13 of the present application (hereinafter referred to as "invention examples 1 to 13") will be described. Regarding the comparison between invention examples 1 to 13 and the conventional example (the example described in Patent Document 1), as described above, since the difference in the predetermined effects of the present application is obvious in terms of structure, it will not be particularly described together.

[0117] The tire size was set to 245 / 40R19 (specified by JATMA), and a wireless power supply system 50 (invention examples 1 to 13) shown in FIG. 13 was manufactured, and the power supply efficiency from the power transmission coil 52 to the power reception coil 40 was investigated. Regarding the various conditions of the tire 10 included in each of the wireless power supply systems 50 of invention examples 1 to 13, they are as shown in Table 1 below.

[0118]

Table 1

[0119] Regarding the wireless power supply systems of invention examples 1 to 13 manufactured in this way, the ratio (power transmission efficiency) of the power 2 received by the power reception coil 40 (and the resonance circuit of the capacitor) to the power 1 transmitted from the power transmission coil 52 was measured, and these ratios were expressed as indices when invention example 1 was set to 100. The measurement of the ratio of the above powers 1 and 2 was performed using a vector network analyzer. The results are also shown in Table 1. In this specification, it is assumed that the ratio of the transmitted power (power transmission efficiency) is good at 95 or more.

[0120] According to Table 1, it can be seen that all of the wireless power supply systems belonging to the technical scope of the present invention show excellent electromagnetic wave ratios after transmission, and thus achieve excellent power supply efficiency.

Explanation of Signs

[0121] 10 Tire 12 Inner Liner 14 Bead Core 16 bead filler 18 carcass 18a body part 18b folded-back part 19 steel reinforcement 20 belt 20a, 20b belt layers 22 belt cover 22a, 22b, 22c belt cover layers 24 rim cushion 25 second filler 26 side tread 28 wing tip 30 cap tread 32 run-flat liner 40 power receiving coil 41, 41a, 41b fixing members 43 wire 44 power line 46 electronic device 50 wireless power supply system 52 power transmission coil 54 wheel house A bead part B side wall part C shoulder part D tread part Dp power supply direction G transmission gap O tire center R1 power receiving coil radial direction region R2 near power receiving region R tire circumferential direction range of 45° on both sides of the virtual line extending vertically upward from the tire center O

Claims

1. A tire having a bead core, a bead filler provided radially outside the bead core in the tire diameter direction, a carcass folded around the bead core, and a belt provided radially outside the carcass in the tire diameter direction, the tire comprising a power receiving coil on the inner surface of the tire cavity for receiving power supplied by an alternating magnetic field from outside the tire, in a tire meridian cross-sectional view, the power receiving coil is provided in a tire diameter direction region from the outermost position of the bead core in the tire diameter direction to the innermost position of the belt in the tire diameter direction, the relative permittivity of members other than the tread portion disposed in the tire diameter direction region is 3.5 or more and 250 or less, A tire characterized by the above.

2. The tire according to claim 1, wherein the relative permittivity of the inner liner is in the range of 8 or more and 90 or less, and the relative permittivity of the carcass is in the range of 4 or more and 20 or less.

3. The tire according to claim 1 or 2, wherein the relative permittivity of the rubber material constituting the side tread is in the range of 3.5 or more and 40 or less, and the relative permittivity of the rubber materials constituting the rim cushion and the bead filler is in the range of 70 or more and 235 or less.

4. The power receiving coil generates power by receiving a magnetic field transmitted from a power transmission coil disposed outside the tire in the tire width direction of the power receiving coil, in a tire meridian cross-sectional view, in a power receiving coil diameter direction region defined by the length in the tire diameter direction between both ends of the power receiving coil in the tire diameter direction, and on both sides in the tire diameter direction adjacent to the power receiving coil diameter direction region, a side tread having a relative permittivity in the range of 3.5 or more and 37 or less is disposed and no rim cushion and bead filler are disposed, The tire according to claim 1 or 2, wherein the relative permittivity of the rim cushion and the bead filler disposed radially inside the power receiving coil diameter direction region and the power receiving vicinity region is in the range of 70 or more and 250 or less.

5. The power receiving coil generates power by receiving a magnetic field transmitted from a power transmission coil disposed outside the tire in the tire width direction of the power receiving coil, in a tire meridian cross-sectional view, in a power receiving coil diameter direction region defined by the length in the tire diameter direction between both ends of the power receiving coil in the tire diameter direction, a side tread having a relative permittivity in the range of 3.5 or more and 37 or less is disposed and no rim cushion and bead filler are disposed, At least a part of a power reception vicinity region that is adjacent to both sides in the tire radial direction with respect to the power reception coil radial direction region and whose length in the tire radial direction is defined as 15% of the length in the tire radial direction of the tire radial direction region of the power reception coil has at least one of a bead filler and a rim cushion whose relative permittivity is in the range of 70 or more and 235 or less. The tire according to claim 1 or 2.

6. The power reception coil receives a magnetic field transmitted from a power transmission coil disposed outside the tire in the tire width direction of the power reception coil and generates electric power. In a tire meridian cross-sectional view, a side tread having a relative permittivity in the range of 3.5 or more and 37 or less is disposed in a power reception coil radial direction region whose length in the tire radial direction is defined by the length between both ends in the tire radial direction of the power reception coil, and at least one of a bead filler and a rim cushion having a relative permittivity in the range of 70 or more and 220 or less is disposed. The tire according to claim 1 or 2.

7. The power reception coil receives a magnetic field transmitted from a power transmission coil disposed outside the tire in the tire width direction of the power reception coil and generates electric power. In a tire meridian cross-sectional view, at least one of a bead filler and a rim cushion having a relative permittivity in the range of 70 or more and 200 or less is disposed in a power reception coil radial direction region whose length in the tire radial direction is defined by the length between both ends in the tire radial direction of the power reception coil, and no side tread is disposed. The relative permittivity of the side tread disposed outside the power reception coil radial direction region in the tire radial direction is in the range of 3.5 or more and 40 or less. The tire according to claim 1 or 2.

8. For each member disposed in the tire radial direction region, the difference in relative permittivity from another member adjacent in the tire width direction is 170 or less. The tire according to claim 1 or 2.

9. The power reception coil receives a magnetic field transmitted from a power transmission coil disposed outside the tire in the tire width direction of the power reception coil and generates electric power. For a member disposed in a power reception coil radial direction region whose length in the tire radial direction is defined by the length between both ends in the tire radial direction of the power reception coil in a tire meridian cross-sectional view, the difference in relative permittivity from another member adjacent in the tire width direction is 165 or less. The tire according to claim 1 or 2.

10. The conductive wire of the power reception coil is installed via a support layer on the surface of an inner liner that constitutes the tire inner cavity surface. The tire according to claim 1 or 2, wherein a relative permittivity of the support layer existing between the conductive wire and the inner liner in the tire radial direction region is lower than a relative permittivity of the inner liner.

11. The power receiving coil generates electric power by receiving a magnetic field transmitted from a power transmitting coil disposed outside the tire in the tire width direction of the power receiving coil, In a tire meridian cross-sectional view, at an arbitrary position on a virtual line in the tire width direction within a power receiving coil radial direction region defined by a length in the tire radial direction being a length between both end portions in the tire radial direction of the power receiving coil, a relationship between a sum of products of relative permittivities of respective members and thicknesses in the tire width direction and a shortest distance Dmin from the conductive wire of the power receiving coil to the inner liner is within a range of formula (1). The tire according to claim 1 or 2. 【Number 1】

12. The tire according to claim 1 or 2, comprising a side support layer on an inner peripheral side of a carcass, wherein the relative permittivity of the side support layer is in a range of 8 or more and 90 or less, and is lower than a relative permittivity of a higher one of a rim cushion and a bead filler.

13. In a tire meridian cross-sectional view, in a power receiving coil radial direction region defined by a length in the tire radial direction being a length between both end portions in the tire radial direction of the power receiving coil, a maximum value of a thickness of the side support layer in the tire width direction is in a range of 4 mm or more and 12 mm or less. The tire according to claim 12.

14. A wireless power supply system that supplies AC power to a power transmitting coil that forms a resonance circuit with a capacitor and a coil, and transmits power to the power receiving coil that forms a resonance circuit with the capacitor and the coil, the wireless power supply system including the tire according to claim 1 or 2.

15. The wireless power supply system according to claim 14, wherein at least a part of the power receiving coil is located within a power supply region that extends in a winding axis direction of the power transmitting coil between both longitudinal end portions of the power transmitting coil in a tire meridian cross-sectional view.

16. The wireless power supply system according to claim 14 or 15, wherein the power transmitting coil is installed within a range of 60° on both sides in a tire circumferential direction centered on a virtual line extending vertically upward from the tire center.

17. The wireless power supply system according to claim 14 or 15, wherein the power transmitting coil is installed on a spring lower member of a vehicle.

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