Tire and wireless power supply system

Abstract

Provided is a tire in which, even if a steel cord is used in a belt, a magnetic field from a power transmission coil to a power reception coil is not hindered by a metal member, and excellent power feeding efficiency can be achieved. In a tire meridian cross-sectional view, a power reception coil (40) is disposed in a tire radial direction region (WH) from a tire radial direction outermost position of a bead core (14) to a tire radial direction innermost position of a belt (20), and a relative dielectric constant of a member disposed in the tire radial direction region, other than a tread portion, is 3.5 or more and 250 or less.

Description

Technical Field

[0001] This invention relates to a tire and a wireless power supply system that improves power supply efficiency. Background Technology

[0002] Previously, the industry disclosed a wireless power receiving system that supplies power between a power transmission coil buried near the road surface and a power receiving coil mounted on the centerline of the tire width direction of a wheel (e.g., Patent Document 1, ...). Figure 1 ).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-059302 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] Patent Document 1 discloses a wireless power receiving system in which steel cords can be used for the belts constituting the tire (

[0022] ). However, when steel cords are used for the belts, a portion of the magnetic field that should have reached the receiving coil from the power supply coil is blocked by the belts, which may prevent the achievement of excellent power supply efficiency.

[0008] During tire rolling, the use of brakes generates iron dust from the brake discs and brake pads. In wireless power receiving systems, this iron dust can block a portion of the magnetic field that should be traveling from the transmitting coil to the receiving coil.

[0009] In the wireless power receiving system of Patent Document 1, the receiving coil is usually mounted on a metal rim. Therefore, the alternating magnetic field is affected by the rim, and there is a tendency for the acceptable power of the receiving coil to decrease. On the other hand, when the receiving coil is mounted off the ground from the metal rim, although the power supply efficiency is improved, it is difficult to dissipate the heat generated by the receiving coil.

[0010] The first objective of this invention is to provide a tire and a wireless power supply system using the tire, wherein even when steel cords are used in the tire belt, the magnetic field from the power supply coil to the power receiving coil is not obstructed by the metal component present between the two coils, thereby achieving excellent power supply efficiency.

[0011] The second objective of this invention is to provide a tire capable of suppressing the influence of iron powder generated from the brake disc and brake pads on the power receiving system, and a wireless power supply system using the tire.

[0012] A third objective of the present invention is to provide a tire capable of achieving excellent power supply efficiency by selecting the location of the power receiving coil and the heat dissipation method at that location, and a wireless power supply system using the tire.

[0013] Solution for solving the problem

[0014] According to the present invention, the following forms 1 to 17 are provided as means for achieving the first objective (first invention), the following forms 18 to 27 are provided as means for achieving the second objective (second invention), and the following forms 28 to 36 are provided as means for achieving the third objective (third invention).

[0015] [Form 1]

[0016] A tire has a bead core, a sidewall core disposed radially outward of the bead core, a carcass folded back around the bead core, and a belt disposed radially outward of the carcass. A receiving coil is located on the inner surface of the tire cavity, the receiving coil receiving electricity supplied from outside the tire via an alternating magnetic field.

[0017] The tire is characterized in that, in a radial cross-sectional view of the tire, the receiving coil is disposed in the radial region of the tire extending from the outermost radial position of the bead core to the innermost radial position of the belt.

[0018] The relative permittivity of the components disposed in the radial region of the tire, excluding the tread portion, is 3.5 or higher and 250 or lower.

[0019] [Form 2]

[0020] According to the tire of form 1, the relative permittivity of its inner liner is in the range of 8 to 90, and the relative permittivity of the tire carcass is in the range of 4 to 20.

[0021] [Form 3]

[0022] According to the tire described in form 1 or 2, the relative permittivity of the rubber material constituting the sidewall tread is in the range of 3.5 to 40, and the relative permittivity of the rubber material constituting the rim protector and the sidewall core is in the range of 70 to 235.

[0023] [Form 4]

[0024] According to any one of embodiments 1 to 3, in a tire, the receiving coil generates electricity by receiving a magnetic field transmitted from a supply coil disposed outside the tire in the tire width direction.

[0025] In a radial cross-sectional view of the tire, a sidewall tread with a relative permittivity between 3.5 and 37 is provided in the radial region of the coil, defined by the length between the two radial ends of the coil, and in the vicinity of the coil, which is adjacent to both radial sides of the coil and defined by a radial length of 15% of the radial length of the coil. No rim protector or sidewall core is provided.

[0026] The relative permittivity of the rim protector and sidewall core disposed on the radial inner side of the tire in the radial region of the receiving coil and the region near the receiving coil is in the range of 70 to 250.

[0027] [Form 5]

[0028] According to any one of forms 1 to 4, in a tire, the receiving coil generates electricity by receiving a magnetic field transmitted from a supply coil disposed outside the tire in the tire width direction.

[0029] In a radial cross-sectional view of the tire, in the radial region of the coil, whose radial length is defined by the length between the two radial ends of the coil, a sidewall tread with a relative permittivity between 3.5 and 37 is provided, and no rim protector or sidewall core is provided.

[0030] At least a portion of the near-electric region adjacent to the radial sides of the tire relative to the radial region of the receiving coil, and the length of the tire's radial direction is defined as 15% of the radial length of the tire's radial region, is provided with at least one of a sidewall core and a rim protector having a relative permittivity in the range of 70 to 235.

[0031] [Form 6]

[0032] According to any one of forms 1 to 5, in a tire, the receiving coil generates electricity by receiving a magnetic field transmitted from a supply coil disposed outside the tire in the tire width direction.

[0033] In a radial section view of the tire, in the radial region of the coil, whose radial length is defined by the length between the two radial ends of the coil, a sidewall tread with a relative permittivity of 3.5 to 37 is provided, and at least one of a sidewall core and a rim protector with a relative permittivity of 70 to 220 is provided.

[0034] [Form 7]

[0035] According to any one of forms 1 to 6, in a tire, the receiving coil generates electricity by receiving a magnetic field transmitted from a supply coil disposed outside the tire in the tire width direction.

[0036] In a radial cross-sectional view of the tire, in the radial region of the coil receiving coil, whose radial length is defined by the length between the two radial ends of the coil receiving coil, at least one of a sidewall core and a rim protector is provided, with a relative permittivity in the range of 70 to 200, and no sidewall tread is provided. The relative permittivity of the sidewall tread disposed radially outside the radial region of the coil receiving coil is in the range of 3.5 to 40.

[0037] [Form 8]

[0038] According to any one of forms 1 to 7, the tire has a relative permittivity difference of 170 or less between each component disposed in the radial region of the tire and other components adjacent to it in the tire width direction.

[0039] [Form 9]

[0040] According to any one of embodiments 1 to 8, in the tire described in embodiment 2, the receiving coil generates electricity by receiving a magnetic field transmitted from a transmitting coil disposed outside the tire in the tire width direction.

[0041] In a radial section view of the tire, the difference in relative permittivity between the member of the radial region of the coil, whose length is defined by the length between the two radial ends of the coil, and other members adjacent to it in the tire width direction is 165 or less.

[0042] [Form 10]

[0043] In any one of the forms 1 to 9, the conductive wire dielectric support layer of the receiving coil is disposed on the inner liner surface constituting the inner cavity surface of the tire.

[0044] The relative permittivity of the support layer, which exists between the conductive wire and the liner in the radial region of the tire, is lower than that of the liner.

[0045] [Form 11]

[0046] According to any one of forms 1 to 10, in a tire, the receiving coil generates electricity by receiving a magnetic field transmitted from a supply coil disposed outside the tire in the tire width direction.

[0047] In a radial section view of the tire, the sum of the products of the relative permittivity of each component and the thickness in the tire width direction on a virtual line in the radial region of the coil, at any position in the radial region of the coil defined by the length between the two ends of the coil in the radial direction of the tire, and the relationship between the shortest distance Dmin from the conductive line of the coil to the liner, are within the range of Equation (1).

[0048] [Formula 1]

[0049]

[0050] [Form 12]

[0051] According to any one of forms 1 to 11, the tire has a sidewall support layer on the inner circumferential side of the tire carcass, the relative permittivity of the sidewall support layer being in the range of 8 to 90, and being lower than the relative permittivity of the rim protector and the sidewall core, which has a higher relative permittivity.

[0052] [Form 13]

[0053] According to the tire of form 12, in a radial cross-sectional view of the tire, in the radial region of the coil whose radial length is defined by the length between the two ends of the coil in the radial direction of the tire, the maximum value of the thickness of the sidewall support layer in the tire width direction is in the range of 4 mm to 12 mm.

[0054] [Form 14]

[0055] A wireless power supply system provides AC power to a transmitting coil that forms a resonant circuit consisting of a capacitor and a coil, transmits power to a receiving coil that forms a resonant circuit consisting of a capacitor and a coil, and includes a tire as described in any one of forms 1 to 13.

[0056] [Form 15]

[0057] According to the wireless power supply system of form 14, in a tire radial section view, at least a portion of the receiving coil is located in a power supply area extending between the two ends of the transmitting coil along the length direction and along the winding axis of the transmitting coil.

[0058] [Form 16]

[0059] According to the wireless power supply system of form 14 or 15, the power supply coil is disposed within a range of 60° on both sides of the tire circumference centered on a virtual line extending vertically upward from the center of the tire.

[0060] [Form 17]

[0061] According to any one of forms 14 to 16, the wireless power supply system wherein the power supply coil is disposed on the unsprung component of the vehicle.

[0062] [Form 18]

[0063] A tire has a bead core, a sidewall core disposed radially outward of the bead core, a carcass folded back around the bead core, and a belt disposed radially outward of the carcass. A receiving coil is located on the inner surface of the tire cavity, the receiving coil receiving electricity supplied from outside the tire via an alternating magnetic field.

[0064] The tire is characterized in that, in a radial cross-sectional view of the tire, the receiving coil is disposed within the radial region of the tire extending from the outermost radial position of the bead core to the innermost radial position of the belt.

[0065] It has an outer layer of rubber exposed on the tire sidewall in the radial region of the tire.

[0066] The outer rubber layer contains an anti-aging agent in the amount of 0.5 to 8.0 parts by weight relative to 100 parts by weight of the rubber, and contains wax in the amount of 0.1 to 5.0 parts by weight relative to 100 parts by weight of the rubber.

[0067] [Form 19]

[0068] According to the tire of form 18, the thickness of the outer rubber layer is in the range of 2.5 to 20.0 mm.

[0069] [Form 20]

[0070] The tire described in form 18 or 19 is mounted on a specified rim and subjected to a standard internal pressure.

[0071] The radial length SH of a tire under no load, from the toe to the tread surface, and...

[0072] The tire's deflection in the width direction, D, before and after applying a load corresponding to 80% of the normal load.

[0073] It satisfies the following equation (2).

[0074] 0.0278×SH-1.33≤D≤0.286×SH-13.7……(2)

[0075] [Form 21]

[0076] The tire according to any one of forms 18 to 20, wherein the cross-sectional area S of the outer rubber layer is... o With 100% modulus M o The sum of the products of, and

[0077] The cross-sectional area S of the inner rubber layer disposed inside the tire width direction of the outer rubber layer and not exposed on the tire sidewall. i With 100% modulus M i The sum of their products satisfies the following equation (3).

[0078] [Formula 2]

[0079]

[0080] [Form 22]

[0081] The tire according to any one of forms 18 to 21, wherein the height of the unevenness on the outer rubber surface is less than 2.0 mm.

[0082] [Form 23]

[0083] According to any one of forms 18 to 22, in a radial sectional view of the tire, the radial length of the coil is defined by the length between the two radial ends of the coil, and the near-current receiving area is adjacent to both sides of the radial direction of the tire relative to the radial region of the coil, and the radial length of the coil is defined by 15% of the radial length of the radial region of the tire.

[0084] The outer rubber layer contains an anti-aging agent in the form of 0.5 to 7.5 parts by weight relative to 100 parts by weight of the rubber, and also contains wax in the form of 0.1 to 4.5 parts by weight relative to 100 parts by weight of the rubber.

[0085] The height of the unevenness on the outer rubber surface is less than 1.5 mm.

[0086] [Form 24]

[0087] A wireless power supply system provides AC power to a transmitting coil that forms a resonant circuit of a capacitor and a coil, and transmits power to a receiving coil that forms a resonant circuit of a capacitor and a coil, characterized in that it comprises a tire as described in any one of forms 18 to 23.

[0088] [Form 25]

[0089] According to the wireless power supply system of form 24, in a tire radial section view, at least a portion of the receiving coil is located in a power supply area extending along the winding axis of the transmitting coil between the two ends of the transmitting coil in the longitudinal direction.

[0090] [Form 26]

[0091] According to the wireless power supply system of form 24, the power supply coil is disposed within a range of 60° on both sides of the tire circumference centered on a virtual line extending vertically upward from the center of the tire.

[0092] [Form 27]

[0093] According to the wireless power supply system of form 24, the power supply coil is disposed on the unsprung component of the vehicle.

[0094] [Form 28]

[0095] A tire has a bead core, a sidewall core disposed radially outward of the bead core, a carcass folded back around the bead core, and a belt disposed radially outward of the carcass. An electric coil is located on an inner cavity surface, the electric coil receiving electricity supplied from outside the tire via an alternating magnetic field.

[0096] The tire is characterized in that, in a radial cross-sectional view of the tire, in the radial region between the two feet of a perpendicular line drawn from the two ends of the tire radially connected to the inner liner formed on the inner periphery of the tire body, the thermal conductivity λ1 of the inner liner is 0.10 W / m・K or higher.

[0097] [Form 29]

[0098] According to the tire of configuration 28, in a radial cross-sectional view of the tire, the receiving coil is disposed in the radial region of the tire from the outermost radial position of the bead core to the innermost radial position of the belt.

[0099] [Form 30]

[0100] According to the tire described in form 28 or 29, in a radial section of the tire cut at a location other than the end of the receiving coil, the total cross-sectional area S (m²) of the conductors of the receiving coil is... 2 The relationship between the resistance value r (Ω) of the receiving coil at the frequency of the AC power and the thermal conductivity λ1 (W / m·K) of the lining satisfies

[0101] 1×10 5 ≤r / (λ1×S)≤8×10 7 .

[0102] [Form 31]

[0103] According to any one of forms 28 to 30, in the tire radial region from the outermost radial position of the bead core to the innermost radial position of the belt, the thermal conductivity λ2 of the rubber layer other than the inner liner is 0.13 W / m・K or higher.

[0104] [Form 32]

[0105] The tire according to any one of forms 28 to 31 includes a fixing member for fixing the receiving coil to the inner surface of the tire cavity.

[0106] With the tire center as a reference, the ratio of the sum of the tire circumferential setting angles θ2 of the fixing member ∑θ2 to the tire circumferential setting angle θ1 of the receiving coil 40 [(∑θ2) / θ1] satisfies the following relationship with the thermal conductivity λ3 (W / m・K) of the fixing member.

[0107] 0.14×[(∑θ2) / θ1]+0.13≤λ3≤0.38×[(∑θ2) / θ1]+0.42.

[0108] [Form 33]

[0109] According to any one of forms 28 to 32, the tire wherein the conductor constituting the receiving coil comprises a wire and a covering layer covering the wire, the thermal conductivity λ4 (W / m·K) of the covering layer is greater than the thermal conductivity λ1 (W / m·K) of the inner liner, and the thickness of the covering layer is 10 to 100 μm.

[0110] [Form 34]

[0111] A wireless power supply system provides AC power to a transmitting coil that forms a resonant circuit of a capacitor and a coil, and transmits power to a receiving coil that forms a resonant circuit of a capacitor and a coil, characterized in that it comprises a tire as described in any one of forms 28 to 33.

[0112] [Form 35]

[0113] According to the wireless power supply system of form 34, in a tire radial section view, at least a portion of the receiving coil is located in a power supply area extending between the two ends of the transmitting coil along the length direction and along the winding axis of the transmitting coil.

[0114] [Form 36]

[0115] According to the wireless power supply system of form 34 or 35, the power supply coil is disposed within a range of 60° on both sides of the tire circumference centered on a virtual line extending vertically upward from the center of the tire.

[0116] Invention Effects

[0117] In the tire of the first invention, the position of the receiving coil in the inner surface of the tire and the relative permittivity of the components were improved. As a result, the tire according to the invention can improve power supply efficiency.

[0118] In the tire of the second invention, the position of the receiving coil within the tire's inner surface has been improved. Furthermore, the tire of the present invention limits the content of anti-aging agents and waxes contained in the outer rubber layer exposed on the tire sidewall. As a result, the tire according to the present invention can improve power supply efficiency. Moreover, the tire of the present invention can maintain weather resistance over many years of use while suppressing a decrease in power supply efficiency.

[0119] In the tire of the third invention, the location of the receiving coil in the inner surface of the tire and the heat dissipation method at that location have been improved. As a result, the tire according to the invention can improve power supply efficiency. Attached Figure Description

[0120] Figure 1 This is a radial cross-sectional view of the tire in the first embodiment, showing a portion of the tire on one side in the tire width direction based on the tire equator plane (not shown).

[0121] Figure 2 It means Figure 1 The figure shows the tire 10 further equipped with a zero-pressure liner 32.

[0122] Figure 3 It means Figure 1 The diagram shows the tire 10 further equipped with a second filler 25.

[0123] Figure 4 It means Figure 1 The figure shows the tire 10 further equipped with a steel reinforcement (SRF) 19.

[0124] Figure 5 This is a radial cross-sectional view of the tire 10 in additional embodiment 4, showing the main part of the tire.

[0125] Figure 6 This is a schematic diagram illustrating the radial region R1 of the receiving coil, and a diagram showing the state of the tire 10 as viewed from the tire width direction.

[0126] Figure 7 This is a radial cross-sectional view of the tire 10 in additional embodiment 5, showing the main part of the tire.

[0127] Figure 8 This is a radial cross-sectional view of the tire 10 in additional embodiment 6, showing the main part of the tire.

[0128] Figure 9 This is a radial cross-sectional view of the tire 10 showing the main part of the tire 10 in Additional Embodiment 6, and a diagram showing the tire 10 having the second filler 25.

[0129] Figure 10 This is a radial cross-sectional view of the tire 10 in additional embodiment 7, showing the main part of the tire.

[0130] Figure 11 This is a radial cross-sectional view of the tire 10 showing the main part of the tire 10 in the additional embodiment 10, and an enlarged view showing the current receiving coil 40 and its surrounding area provided on the surface of the inner liner 12 of the tire cavity by the spacer support layer 44.

[0131] Figure 12 This is a radial cross-sectional view of the tire 10 in the additional embodiment 11, showing the main part of the tire 10. It is an enlarged view showing the current receiving coil 40 and its surrounding area provided on the surface of the inner liner 12 of the tire cavity by the spacer support layer 44.

[0132] Figure 13 This diagram shows the power supply coil 52 in the wireless power supply system 50 of this embodiment, and the tire 10 (the part on the tire width direction with the tire equatorial plane CP as the reference in the radial section view of the tire) equipped with the power receiving coil 40.

[0133] Figure 14 This is a diagram showing the overlap pattern between the tire radial position of the power supply coil 52 and the tire radial position of the power receiving coil 40 in the wireless power supply system 50 of this embodiment. (a) shows an example where the outer radial portion of the power supply coil 52 overlaps with the inner radial portion of the power receiving coil 40. (b) shows an example where the inner radial portion of the power supply coil 52 overlaps with the outer radial portion of the power receiving coil 40.

[0134] Figure 15 This is a diagram showing the installation position of the power transmission coil 52 in the wireless power supply system 50 of this embodiment.

[0135] Figure 16 It is used to explain in Figure 1 A schematic diagram showing the location of the power supply coil 52 in the tire 10.

[0136] Figure 17 It is used to explain in Figure 1 A schematic diagram showing the location of the power supply coil 52 in the tire 10.

[0137] Figure 18 This indicates the configuration of the receiving coil 40 (and...). Figure 2 The diagrams (a) to (f) show examples of a current receiving coil 40 consisting of 2, 3, 4, 5, 6, and 8 sets of current receiving coil elements 40a, respectively. (g) shows an example of multiple current receiving coil elements 40a stacked in the radial direction of the tire. (h) shows an example of a portion of multiple current receiving coil elements 40a extending obliquely relative to the radial direction of the tire.

[0138] Figure 19 It means in Figure 1 The tire shown is a radial cross-sectional view of the tire 10 in which power is supplied from the receiving coil 40 to the electronic device 47 mounted on the inner surface of the tire via the power line 45 (however, it is half in the tire width direction).

[0139] Figure 20 This is a meridian cross-sectional view of one side of the tire width direction, with the tire equatorial plane (not shown) as the reference, in the tire of the second embodiment.

[0140] Figure 21 This is a radial cross-sectional view showing an improved example of the tire according to the second embodiment.

[0141] Figure 22 This is a meridional cross-sectional view used to illustrate the deflection amount in the tire width direction of the tire according to the second embodiment.

[0142] Figure 23 This is a meridional cross-sectional view of one side of the tire width direction, with the tire equatorial plane (not shown) as a reference, in the tire of the third embodiment.

[0143] Figure 24 It means Figure 23 This is a schematic diagram showing the configuration of the receiving coil 40 in the tire circumferential direction.

[0144] Figure 25 This indicates that the fixed component 41 is relative to... Figure 23 The schematic diagram shows a specific example of the setting ratio of the receiving coil 40, namely [(∑θ2) / θ1]. (A) shows an example of setting multiple fixed members 41a at certain intervals, and (B) shows an example of setting one fixed member 41b.

[0145] Figure 26 This is a cross-sectional view showing the wires 42 that make up the current receiving coil 40. Detailed Implementation

[0146] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the tire radial direction refers to the direction orthogonal to the tire's rotation axis; the inner side of the tire radial direction refers to the side facing the tire's rotation axis in the tire's radial direction; and the outer side of the tire radial direction refers to the side away from the tire's rotation axis in the tire's radial direction. Furthermore, the tire circumferential direction refers to the circumferential direction about the tire's rotation axis. Moreover, the tire width direction refers to the direction parallel to the tire's rotation axis; the inner side of the tire width direction refers to the side facing the tire's equatorial plane (tire equator) in the tire's width direction; and the outer side of the tire width direction refers to the side away from the tire's equatorial plane in the tire's width direction. It should be noted that the tire equatorial plane is a plane orthogonal to the tire's rotation axis that passes through the center of the tire's width.

[0147] Similarly, in the following description, a standard rim refers to the “applicable rim” as defined by JATMA (Japan Automobile Tire Manufacturers Association), the “Design Rim” as defined by TRA (American Tire & Rim Association), or the “Measuring Rim” as defined by ETRTO (European Tire & Rim Technology Organization).

[0148] Similarly, in the following description, standard tire pressure refers to the "maximum tire pressure" specified by JATMA, the maximum value recorded in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" specified by TRA, or "INFLATION PRESSURES" specified by ETRTO. Furthermore, standard load refers to the "maximum load capacity" specified by JATMA, the maximum value recorded in "TIRE LOAD LIMITS ATVARIOUS COLD INFLATION PRESSURES" specified by TRA, or "LOADCAPACITY" specified by ETRTO.

[0149] <Tires>

[0150] 1. First Implementation Method

[0151] Hereinafter, the tire of the present invention (basic embodiment 1 and additional embodiments 2-13 shown below) and the first embodiment of the wireless power supply system of the present invention (basic embodiment 14 and additional embodiments 15-17 shown below) will be described in detail based on the accompanying drawings. It should be noted that these embodiments do not limit the present invention. Furthermore, the constituent elements of each embodiment include elements that can be easily replaced by those skilled in the art, or substantially the same elements. Moreover, the embodiments can be arbitrarily combined within the scope that is obvious to those skilled in the art.

[0152] [Basic Implementation Method 1]

[0153] Figure 1 This is a radial cross-sectional view of the tire of the first embodiment, showing a portion of the tire on one side in the tire width direction with reference to the tire equatorial plane (not shown). It should be noted that this figure shows the tire portion on the side opposite to the contact patch when assembled to the rim and subjected to normal internal pressure and normal load (hereinafter, the same applies to the invention of the tire).

[0154] like Figure 1 As shown, the tire 10 of this embodiment has a bead portion A, a sidewall portion B, a shoulder portion C, and a tread portion D extending radially from the inner side of the tire to the outer side. An inner liner 12 exposed to the inner surface of the tire is provided in the area from the bead portion A to the tread portion D. A tire body 18 is provided on the side of the inner liner 12 opposite to the inner surface of the tire. The tire body 18 includes a main body portion 18a extending along the inner liner 12 and a folded-back portion 18b that wraps around the bead core 14 and the sidewall core 16. On the radial outer side of the tire body 18 at 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 radially outward.

[0155] Furthermore, a rim protector 24 is provided further outward in the tire width direction of the folded portion 18b of the tire carcass 18, which is located on the outer side of the bead core 14 and the sidewall core 16. A sidewall tread 26, a wing tip 28, and a crown 30 are sequentially provided on the outer radial side of the rim protector 24.

[0156] Figure 2 express Figure 1 The tire 10 further includes a zero-pressure liner 32. The zero-pressure liner 32 is formed at least throughout the sidewall portion B (and may also include the bead portion A and the shoulder portion C) on the outer side of the inner liner 12 in the tire width direction. The tire of this embodiment is not limited to... Figure 1 The examples shown also include, for example, Figure 2 The example shown is a run-flat tire in which a zero-pressure liner 32 is provided on the outer side of the inner liner 12 in the tire width direction, mainly in the sidewall portion B.

[0157] also, Figure 3 express Figure 1 The tire 10 further includes a second filler 25. The second filler 25 is made of a different rubber than the rim protector 24, and as shown in the illustrated example, it is disposed on the outer side of the fold-back portion 18b in the tire width direction, adjacent to the fold-back portion 18b of the tire carcass 18. Furthermore, Figure 4 express Figure 1The tire 10 further includes a steel reinforcement (SRF) 19. As shown in the example, the steel reinforcement 19 is disposed adjacent to the folded-back portion 18b of the tire carcass 18 in the tire width direction inside the folded-back portion 18b. By providing the second filler 25 or the steel reinforcement 19, the rigidity of the sidewall portion B can be improved. The tire of this embodiment is not limited to... Figure 1 The examples shown also include, for example, Figure 3 and Figure 4 A tire with a second filler 25 or a steel reinforcement 19 as shown.

[0158] In the tire 10 configured as described above, the inner liner 12 is a layer used to block gas from contacting the inner surface of the tire. The inner liner 12 may consist of a single inner liner layer or multiple inner liner layers stacked radially along the tire equator. The inner liner 12 includes at least one layer made of low-permeability rubber or resin, and may include an adhesive layer as an additional layer at least in the contact portion with the tire carcass 18.

[0159] The bead core 14 is, for example, an annular reinforcement formed by bundling cords, and can be configured as a structure in which rubber is used to cover the area around multiple bead wires made of steel cords or organic fiber cords. The sidewall core 16 is a component used to improve the rigidity of the bead portion A, and can be configured as follows: Figure 1 The approximate triangular shape shown has a tire width dimension at the inner radial end of the tire and a tire width dimension at the outer radial end of the tire bead core 14 that are approximately equal, and the tire width dimension gradually decreases towards the outer radial direction of the tire.

[0160] The carcass 18 is a component forming the skeleton of the tire 10, and is composed of at least one carcass layer (carcass ply), each carcass layer having a structure in which multiple carcass cords are covered with rubber. Typically, steel cords or organic fiber cords are used as carcass cords. However, in the tire 10 of this embodiment, as described later, in order to prevent the magnetic field generated in the sidewall portion B, which penetrates substantially perpendicularly through the inner surface of the tire liner 12, from being obstructed by the metal component, it is preferable to use a non-magnetic material as the carcass cord. For example, organic fibers such as rayon, polyester, polyamide, and aramid can be used as non-magnetic materials.

[0161] The belt 20 is a reinforcing layer disposed on the radially outer side of the tire carcass 18. It is a component that secures the tire carcass 18, increases the rigidity of the tread portion D, thereby improving driving stability, and reduces rolling resistance by decreasing strain deformation. The belt 20 can be composed of multiple belt layers stacked radially along the tire tread portion D (in... Figure 1The example shown consists of two bundle layers 20a and 20b. Each bundle layer 20a and 20b is composed of multiple bundle cords covered with rubber. Typically, steel cords or organic fiber cords are used as bundle cords. As bundle cords, it is natural to use magnetic materials such as steel cords, but non-magnetic materials (including paramagnetic and diamagnetic materials) can also be used.

[0162] The belt cover 22 is a component that enhances the securing effect of the belt 20 to the tire carcass 18, particularly for preventing deformation of the tread portion D due to centrifugal forces generated during high-speed vehicle operation. The belt cover 22 can be composed of multiple belt cover layers stacked radially outward from the tire on the radial side of the belt 20. Figure 1 The example shown consists of three belt cover layers 22a, 22b, and 22c. Each belt cover layer 22a, 22b, and 22c has a structure in which multiple cords are rubber-coated. Typically, steel cords or organic fiber cords are used as the cords used in the belt cover layers. As for the cords, it is natural to use magnetic materials such as steel cords, but non-magnetic materials (including paramagnetic and diamagnetic materials) can also be used.

[0163] The rim protector 24 is disposed in the area that contacts the rim flange of a wheel (not shown), and the sidewall tread 26 is configured to connect the rim protector 24 to the tread portion D. In the radial sectional view of the tire, winglets 28 are respectively disposed at the boundaries of the tread portion D and the sidewall tread 26 on the left and right sides of the tire, and the crown 30 is formed on the surface of the tread portion D in a manner that covers the entire area of ​​the tire contact patch. It should be noted that the rim protector 24, the second filler 25, the sidewall tread 26, the winglets 28, the crown 30, and the zero-pressure liner 32 can all use conventionally used rubber components according to their respective required characteristics.

[0164] To exist Figure 1 The tire 10 shown includes components 12 to 30 (and, depending on the situation, also includes...). Figure 2 Zero-pressure liner 32 Figure 3 Second filler 25 Figure 4 Provided that at least one of the steel reinforcement members 19 is present, the tire 10 of this embodiment has a receiving coil 40 on the inner side of the tire cavity surface in the tire width direction. Figure 1 The receiving coil 40 receives alternating current from a power supply coil (not shown) disposed outside the tire 10. Here, power transmission can be, for example, based on magnetic field resonance. The receiving coil 40 can be disposed in contact with the inner liner 12, or it can be embedded in the inner liner 12. Furthermore, the receiving coil 40 can also be configured to be fixed to the inner liner 12 via a fixing member other than rubber (e.g., made of a non-magnetic material, especially a rubber with relatively high thermal conductivity such as silicone rubber for the fixing part). Figure 1It should be noted that, when a zero-pressure liner is provided, the receiving coil 40 can also be provided on the inner circumference of the liner 12.

[0165] In the power supply of the tire 10 using this embodiment, for example, a direct current obtained from an on-board battery (not shown) is temporarily converted into an alternating current by an AC power supply device, and this alternating current is applied to a power supply coil (e.g., mounted on the tire side surface of a steering knuckle or wheel hub, which is a component of the vehicle's steering axle, or any component constituting the strut structure), thereby generating an alternating magnetic field around the power supply coil. This alternating magnetic field links with a receiving coil 40, thereby generating an induced electromotive force in the receiving coil 40 to supply power.

[0166] In achieving such power supply, in the tire 10 of this embodiment, in the tire radial section view ( Figure 1 The receiving coil 40 is positioned at the outermost radial position of the tire from the bead core 14. Figures 1-3 Point P1 (as shown) to the innermost radial position of the tire of belt 20 ( Figures 1-3 The radial region of the tire up to point P2 (as shown). Figure 1 As shown, the radial region of the tire is the area with a radial length of WH that extends along the tire width direction in the radial section view of the tire. Hereinafter, for ease of explanation, the radial region of the tire will be denoted by the reference numeral WH.

[0167] More specifically, the tire radial region WH is the tire radial region defined by the outer radial end of the bead core 14 (point P1), which may contain a strong magnetic material, and the innermost radial position of the belt 20 (point P2, the outer radial end of the belt 20 in the tire width direction), which may contain a strong magnetic material. It is a region further radially outer than point P1 and further radially inner than point P2. It should be noted that in the tire radial region WH, the tire 10 is curved in an outwardly convex shape. Therefore, if the current-receiving coil 40 is provided in the tire radial region WH, the current-receiving coil 40 is generally positioned further radially outer than points P1 and P2. However, this is not limited to the tire width direction positions of points P1 and P2. That is, if point P1 is clearly located further radially inner than point P2, and the current-receiving coil 40 is positioned near the bead core 14, it is possible that the current-receiving coil 40 is positioned further radially inner than the width direction end of the belt 20 (point P2). Furthermore, if point P1 is located significantly further outward in the tire width direction than point P2, and the power receiving coil 40 is positioned near the belt 20, there may be a situation where the power receiving coil 40 is positioned further inward in the tire width direction than the radially outer end (point P1) of the bead core 14.

[0168] Figures 1-3The diagram shows a case where there is no strong magnetic material surrounding the bead core 14. On the other hand, Figure 4 This illustration shows a case where a steel reinforcement (SRF) 19 is provided around the bead core 14 (located further radially outward than the bead core 14) as a reinforcement for strong magnetism. Figure 4 In the case of tire 10 shown, the innermost radial position of the tire radial region WH is... Figure 4 Point P3 is shown.

[0169] Furthermore, in the tire 10 of this embodiment, the relative permittivity (the ratio of the permittivity of a specific component to the permittivity of vacuum, hereinafter the same) of the components disposed in the radial region WH of the tire, excluding the tread portion D, from the outermost radial position of the bead core 14 to the innermost radial position of the belt 20, is 3.5 or more and 250 or less. It should be noted that "components other than the tread portion D" refers to the remaining components other than the crown 30, wing tip 28, belt cover 22, belt edge pad, etc.

[0170] (Functions, etc.)

[0171] As described above, a wireless power receiving system that supplies power between a power transmission coil buried near the road surface and a power receiving coil mounted on the centerline of the tire width direction of a wheel is previously known (Patent Document 1, Figure 1 In this wireless power receiving system, the magnetic field from the transmitting coil to the receiving coil can sometimes be affected by the belt bundle. For example, in this wireless power receiving system, if the belt bundle uses metal belt cords, a portion of the magnetic field that should reach the receiving coil from the transmitting coil is blocked by the magnetic material (belt cords) contained in the belt bundle, which may prevent the achievement of excellent power supply efficiency.

[0172] Therefore, the inventors have repeatedly conducted in-depth research on the following tire 10: even when Figure 1 When the belt 20 shown uses a metal belt cord, a portion of the magnetic field that should reach the receiving coil 40 from the power supply coil is not blocked by the tire 10, which contains magnetic material between the two coils, thereby achieving excellent power supply efficiency.

[0173] Specifically, the inventors have conducted in-depth research on the optimal position of the receiving coil 40, which is located inside the tire width direction of the inner cavity surface of the tire 10, relative to the power supply coil (not shown) located outside the tire 10.

[0174] Furthermore, the inventors conducted an in-depth study on the range of relative permittivity of the components other than the tread portion D in the radial region WH of the tire, which is located from the outermost radial position of the bead core 14 to the innermost radial position of the tire in the belt 20.

[0175] First, the inventors Figure 1 By focusing on multiple line segments that reach the tire's outer surface from each point (starting point) on the inner surface of the tire with the shortest distance, the following insights were derived: by extracting a region consisting of multiple line segments that do not contain the belt 20 from these line segments, and setting the receiving coil 40 in a manner that does not deviate from the inner surface of the tire contained in the region, most of the magnetic field generated between the two coils will not be blocked by the belt 20, which may contain magnetic material.

[0176] Next, considering that the above-mentioned insights are for defining the radially outer end of the tire in the area where the receiving coil 40 is installed, the inventors further investigated the radially inner end of the tire that defines this area. As a result, the inventors, focusing on the bead core 14 which may be made of a metal component, also concluded that by extracting an area composed of multiple line segments that do not include the bead core 14, and arranging the receiving coil 40 in a manner that does not detach from the inner surface of the tire cavity contained in that area, most of the magnetic field generated between the two coils will not be blocked by the bead core 14, which may contain magnetic material.

[0177] Furthermore, the inventors have concluded that by arranging the receiving coil 40 as described above, when power is supplied from the outside of the tire 10 via electromagnetic induction, it is possible to handle power supply from the tire width direction ( Figure 1 (Arrow a1 direction) Power supply from the outside and from the radial direction of the tire ( Figure 1 Two power supply methods (in the direction of arrow a2) were proposed, and the following conclusions were drawn: The influence of strongly magnetic materials in the belt 20, bead section A, etc., can be minimized, thereby achieving higher transmission efficiency. It should be noted that the strongly magnetic material here mainly refers to iron (steel). For example, the strongly magnetic material in bead section A is the steel cord of the bead core 14 (in... Figure 4 In the example of its composition, the strong magnetic body of the belt 20 (including steel reinforcement 19) is a magnetic material such as steel cord constituting the belt 20.

[0178] Furthermore, the inventors, focusing on the relative permittivity of components disposed near the receiving coil 40, have concluded that the relative permittivity of components disposed in the radial region WH of the tire, excluding the tread portion D, from the outermost radial position of the bead core 14 to the innermost radial position of the belt 20, affects the transmission efficiency of wireless power transmission from the transmitting coil to the receiving coil 40. It should be noted that these components include the inner liner 12, the sidewall core 16, the tire body 18, the rim protector 24, the second filler 25, the sidewall tread 26, the wing tip 28, the zero-pressure liner 32, and other components.

[0179] More specifically, the inventors have concluded that if the relative permittivity of these components is too high, the attenuation of electromagnetic waves during power transmission increases, resulting in reduced transmission efficiency. On the other hand, after further reducing carbon content, the inventors have concluded that if the relative permittivity of these components is too low, it becomes difficult to maintain the original rubber physical properties of these components, thus making it difficult to meet the desired tire performance. It should be noted that the relative permittivity of the carcass 18 is a value when it also includes fiber cords or the like as reinforcement.

[0180] Based on the above insights, in the tire 10 of this embodiment, the receiving coil 40 is disposed in the radial region WH of the tire, from the outermost radial position of the bead core 14 to the innermost radial position of the belt 20. Therefore, according to the tire 10 of this embodiment, since there is no excessive arrangement of tire 10 components that may contain magnetic materials between the supply coil and the receiving coil 40, the power supply efficiency can be improved.

[0181] Furthermore, based on the above insights, in the tire 10 of this embodiment, the relative permittivity of the components disposed in the radial region WH of the tire, excluding the tread portion D, from the outermost radial position of the bead core 14 to the innermost radial position of the belt 20, is 3.5 or more and 250 or less. Here, the aforementioned relative permittivity is preferably set to 4.0 or more and 240 or less, and extremely preferably to 4.5 or more and 230 or less. The relative permittivity is determined by the polymer structure of the components, the compounding agents, etc. The relative permittivity is a measured value at 10 MHz. Furthermore, the dielectric loss tangent (tanδ) of these components is preferably 0.02 to 1.6.

[0182] The relative permittivity and dielectric loss tangent (tanδ) were measured at 23°C and 10MHz. More specifically, the relative permittivity and dielectric loss tangent (tanδ) were measured as follows: a sheet sample of a certain thickness was prepared using a component cut from tire 10, and the relative permittivity and dielectric loss tangent (tanδ) were measured at 10MHz with an AC voltage applied, using a Hewlett Packard HP 4291B RF impedance / material analyzer as the impedance analyzer and a Hewlett Packard 16453A dielectric material test fixture as the test fixture.

[0183] (Additional Implementation Method 2)

[0184] In basic implementation 1, since the magnetic field passes through the inner liner 12 and the tire body 18 when passing through the radial region WH of the tire, the relative permittivity of the inner liner 12 and the tire body 18 has a significant impact on the wireless power supply magnetic field, and thus a significant impact on the transmission efficiency. Furthermore, although the inner liner 12 and the tire body 18 are thinner than other components in the tire width direction, they are expected to be positioned closer to the receiving coil 40 than other components, thus having a greater impact on the wireless power supply magnetic field compared to other components.

[0185] If the relative permittivity of the liner 12 and the carcass 18 is too high, the attenuation of the electromagnetic waves transmitted by electricity will increase, and the transmission efficiency will decrease. On the other hand, if the relative permittivity of the liner 12 and the carcass 18 is too low, it will be difficult to adjust the original rubber physical properties of these components, thus making it difficult to meet the desired tire performance.

[0186] Therefore, in basic embodiment 1, it is preferable that the relative permittivity of the liner 12 is in the range of 8 to 90 and the relative permittivity of the carcass 18 is in the range of 4 to 20 (additional embodiment 2).

[0187] Since the liner 12 includes an air-blocking layer and an adhesive rubber layer, the relative permittivity of the liner 12 is the value of the entire component including the air-blocking layer and the adhesive rubber layer. The relative permittivity of the liner 12 is preferably set to 8.5 or more and 85 or less, and extremely preferably set to 9 or more and 80 or less.

[0188] Furthermore, since the carcass 18 includes reinforcing fibers, the relative permittivity of the carcass 18 is the value of the entire component, including the fiber cords and the like that serve as reinforcing members. The relative permittivity of the carcass 18 is preferably 4.5 or more and 18 or less, and extremely preferably 5 or more and 16 or less. Furthermore, the dielectric loss tangent (tanδ) of the liner 12 is preferably 0.06 to 0.80, and more preferably 0.08 to 0.74. Furthermore, the dielectric loss tangent (tanδ) of the carcass 18 is preferably 0.06 to 0.16, and more preferably 0.07 to 0.15.

[0189] (Additional Implementation Method 3)

[0190] In the basic embodiment 1 or the basic embodiment 1 with the addition of the additional embodiment 2, it is preferable that the relative permittivity of the sidewall tread 26 (the rubber material of the sidewall tread 26) is in the range of 3.5 to 40, and the relative permittivity of the rim protector 24 and the sidewall core 16 (the rubber materials of the rim protector 24 and the sidewall core 16) is in the range of 70 to 235 (additional embodiment 3).

[0191] Both the rim protector 24 and the sidewall core 16 are located near the bead portion A, and the required rubber material properties are largely the same, but differ from those required for the sidewall tread 26. The sidewall tread 26 is expected to be positioned closer to the receiving coil 40 than the rim protector 24 and the sidewall core 16, thus its influence on the wireless power supply magnetic field is expected to be greater than that of the rim protector 24 and the sidewall core 16. According to Additional Embodiment 3, while maintaining the required physical properties (elongation, low heat generation, etc.) for the sidewall tread 26 and the required physical properties (hardness, elastic modulus, etc.) for the rim protector 24 and the sidewall core 16, a higher transmission efficiency can be maintained. The relative permittivity of the sidewall tread 26 is preferably set to 4.0 or higher and 38 or lower, and extremely preferably 4.5 or higher and 36 or lower. The relative permittivity of the rim protector 24 and the sidewall core 16 is preferably set to 75 or higher and 230 or lower, and extremely preferably 80 or higher and 225 or lower. Furthermore, the dielectric loss tangent (tanδ) of the sidewall tread 26 is preferably 0.02 to 0.5, and more preferably 0.03 to 0.45. Additionally, the dielectric loss tangent (tanδ) of the rim protector 24 and the sidewall core 16 is preferably 0.6 to 1.5.

[0192] It should be noted that, in the presence of such Figure 3 In the case of the tire 10 with the second filler 25 shown, the relative permittivity of the second filler 25 is preferably the same as that of the sidewall core 16. That is, the relative permittivity of the second filler 25 is preferably set to a range of 70 to 235, more preferably 75 to 230, and extremely preferably 80 to 225. Furthermore, the dielectric loss tangent (tanδ) of the second filler 25 is preferably 0.6 to 1.5.

[0193] (Additional Implementation Method 4)

[0194] Figure 5This is a radial cross-sectional view of the tire 10 in additional embodiment 4, showing the main part of the tire. In the basic embodiment 1 or the basic embodiment 1 with at least one of the additional embodiments 2 and 3, it is preferred that, as shown in the figure, the receiving coil 40 generates electricity by receiving a magnetic field transmitted from a power supply coil disposed outside the tire in the tire width direction. In the tire radial cross-sectional view, in the radial region R1 of the receiving coil, whose tire radial length is defined by the length between the two ends of the tire radial direction of the receiving coil 40, and in the near-receiving region R2 adjacent to the radial sides of the tire relative to the radial region R1 and whose tire radial length is defined by 15% of the tire radial length of the radial region WH, a sidewall tread 26 with a relative permittivity in the range of 3.5 to 37 is disposed, and a rim protector 24 and a sidewall core 16 are not disposed. The relative permittivity of the rim protector 24 and the sidewall core 16 disposed on the inner side of the tire radial direction of the receiving coil region R1 and the near-receiving region R2 is in the range of 70 to 250 (additional embodiment 4).

[0195] like Figure 5 As shown, in the additional embodiment 4, the tire 10 is configured such that the entire area of ​​the radial region R1 of the receiving coil and the region near the receiving coil R2 overlaps with the sidewall tread 26 in the tire radial direction, but does not overlap with the rim protector 24 and the sidewall core 16 in the tire radial direction. Figure 5 As shown, the radial region of the receiving coil is a region extending radially with a length of R1 along the tire width direction in a tire radial cross-sectional view. Furthermore, the region near the receiving coil is a region extending radially with a length of R2 along the tire width direction in a tire radial cross-sectional view. For ease of explanation, the radial region of the receiving coil is indicated by reference numeral R1, and the region near the receiving coil is indicated by reference numeral R2. In Additional Embodiment 4, in Figure 5 In the positional relationship shown, the relative permittivity of the sidewall tread 26 is in the range of 3.5 to 37, and the relative permittivity of the rim protector 24 and the sidewall core 16 is in the range of 70 to 250.

[0196] According to Additional Embodiment 4, by arranging the receiving coil 40 in a manner that avoids the radial position of the tire where the rim protector 24 and the sidewall core 16 have relatively high relative permittivity, higher transmission efficiency can be achieved, and the influence of the physical properties of the rim protector 24 and the sidewall core 16 on the transmission efficiency can be suppressed. Therefore, the physical properties of the rim protector 24 and the sidewall core 16 can be set within a range suitable for tire performance. Thus, the relative permittivity of the rim protector 24 and the sidewall core 16 is allowed to be higher than that of Additional Embodiment 3, but the relative permittivity of the sidewall tread 26 has a greater impact on the transmission efficiency, and is therefore suppressed to be lower than that of Additional Embodiment 3. The relative permittivity of the sidewall tread 26 is preferably set to 4.0 or higher and 35 or lower, and extremely preferably to 4.5 or higher and 33 or lower. The relative permittivity of the rim protector 24 and the sidewall core 16 is preferably set to 75 or higher and 240 or lower, and extremely preferably to 80 or higher and 230 or lower. In addition, the dielectric loss tangent (tanδ) of the preferred sidewall tread 26 is 0.02 to 0.47, and the dielectric loss tangent (tanδ) of the rim protector 24 and the sidewall core 16 is 0.6 to 1.6.

[0197] It should be noted that, in the presence of such Figure 3 In the case of the tire 10 with the second filler 25 shown, the relative permittivity of the second filler 25 is preferably the same as that of the sidewall core 16. That is, the relative permittivity of the second filler 25 is preferably set to a range of 70 to 250, more preferably 75 to 240, and extremely preferably 80 to 230. Furthermore, the dielectric loss tangent (tanδ) of the second filler 25 is preferably 0.6 to 1.6.

[0198] Figure 6 This is a schematic diagram illustrating the radial region R1 of the receiving coil, and a diagram showing the state of the tire 10 as viewed from the tire width direction. Figure 6 (A) is an example of multiple coil elements 40a with diameters falling within the radial region WH of the tire arranged circumferentially along the tire, and is an example of the coil 40 being composed of multiple coil elements 40a. Furthermore, Figure 6 (B) is an example of using the entire circumference of the tire to construct a current receiving coil 40. The radial length (=R1) of the radial region R1 of the current receiving coil is the maximum length occupied by the current receiving coil 40 in the radial direction of the tire. Figure 6 (A) and Figure 6 In any example of (B), the radial region R1 of the receiving coil is contained within the radial region WH of the tire.

[0199] (Additional Implementation Method 5)

[0200] Figure 7This is a radial cross-sectional view of the tire 10 showing the main part of the tire according to Additional Embodiment 5. In the basic embodiment 1 or in which at least one of Additional Embodiments 2 to 3 is added, it is preferable that, as shown in this figure, the receiving coil 40 generates electricity by receiving a magnetic field transmitted from a power supply coil disposed outside the tire in the tire width direction. In the radial cross-sectional view of the tire, in the radial region R1 of the receiving coil, whose radial length is defined by the length between the two ends of the radial region of the receiving coil 40, a sidewall tread 26 with a relative permittivity in the range of 3.5 to 37 is provided, and a rim protector 24 and a sidewall core 16 are not provided. In at least a portion of the power receiving vicinity region R2, which is adjacent to the radial sides of the tire relative to the radial region R1 and whose radial length is defined by 15% of the radial length of the tire radial region WH, at least one of a sidewall core 16 with a relative permittivity in the range of 70 to 235 is provided (Additional Embodiment 5).

[0201] like Figure 7 As shown, in the additional embodiment 5, the tire 10 is configured such that the entire radial region R1 of the receiving coil overlaps with the sidewall tread 26 in the tire radial direction, and at least a portion of the near-receiving region R2 overlaps with at least one of the rim protector 24 and the sidewall core 16 in the tire radial direction. Figure 7 The location shown overlaps with the rim protector 24. At least a portion of the area R2 near the power source can also be configured to overlap with both the rim protector 24 and the sidewall core 16 in the tire radial direction. In Additional Embodiment 5, in Figure 7 In the positional relationship shown, the relative permittivity of the sidewall tread 26 is in the range of 3.5 to 37, and the relative permittivity of the rim protector 24 and the sidewall core 16 is in the range of 70 to 235.

[0202] The inner surface of the tire where the receiving coil 40 is located undergoes repeated deformation and release during tire rolling. To improve the durability of the receiving coil 40 against these deformations, it is sometimes preferable to place the receiving coil 40 close to the rim protector 24 or the sidewall core 16 on the radially inner side of the tire. According to Additional Embodiment 5, when it is necessary to place the receiving coil 40 close to the rim protector 24 and the sidewall core 16 for reasons such as durability, the relative permittivity of the rim protector 24 and the sidewall core 16 located in the near-receiving region R2 is set within the aforementioned range. Thus, by not placing the rim protector 24 and the sidewall core 16 in the radial region R1 of the receiving coil, excellent transmission efficiency can be achieved, and by keeping the physical properties of the rim protector 24 and the sidewall core 16 within a range suitable for tire performance, excellent durability can be achieved. The relative permittivity of the sidewall tread 26 is preferably set to 4.0 or higher and 35 or lower, and extremely preferably 4.5 or higher and 33 or lower. The relative permittivity of the rim protector 24 and the sidewall core 16 is preferably set to 75 or more and 230 or less, and extremely preferably to 80 or more and 225 or less. Furthermore, the dielectric loss tangent (tanδ) of the sidewall tread 26 is preferably 0.02 to 0.47, and the dielectric loss tangent (tanδ) of the rim protector 24 and the sidewall core 16 is preferably 0.6 to 1.5.

[0203] It should be noted that, in the presence of such Figure 3 In the case of the tire 10 with the second filler 25 shown, the relative permittivity of the second filler 25 is preferably the same as that of the sidewall core 16. That is, the relative permittivity of the second filler 25 is preferably set to a range of 70 to 235, more preferably 75 to 230, and extremely preferably 80 to 225. Furthermore, the dielectric loss tangent (tanδ) of the second filler 25 is preferably 0.6 to 1.5.

[0204] (Additional Implementation Method 6)

[0205] Figure 8 This is a radial cross-sectional view of the tire 10 showing the main part of the tire according to Additional Embodiment 6. In the basic embodiment 1 or the basic embodiment 1 with at least one of Additional Embodiments 2 to 3 added, it is preferable that, as shown in this figure, the receiving coil 40 generates electricity by receiving a magnetic field transmitted from a power supply coil disposed outside the tire in the tire width direction. In the radial cross-sectional view of the tire, in the radial region R1 of the receiving coil, whose radial length is defined by the length between the two ends of the receiving coil 40 in the tire radial direction, a sidewall tread 26 with a relative permittivity in the range of 3.5 to 37 is disposed, and at least one of a sidewall core 16 with a relative permittivity in the range of 70 to 220 and a rim protector 24 is disposed (Additional Embodiment 6).

[0206] like Figure 8 As shown, in the additional embodiment 6, the tire 10 is configured such that the radial region R1 of the receiving coil overlaps with the sidewall tread 26 in the tire radial direction, and simultaneously overlaps with at least one of the rim protector 24 and the sidewall core 16 (in Figure 8 The location shown is the rim protector 24). The radial region R1 of the receiving coil can also be configured to overlap with both the rim protector 24 and the sidewall core 16 in the tire radial direction. In Additional Embodiment 6, in Figure 8 In the positional relationship shown, the relative permittivity of the sidewall tread 26 is in the range of 3.5 to 37, and the relative permittivity of the rim protector 24 and the sidewall core 16 is in the range of 70 to 220.

[0207] According to Additional Embodiment 6, when at least one of a rim protector 24 and a sidewall core 16 with relatively high relative permittivity is disposed in the radial region R1 of the receiving coil, and a sidewall tread 26 with relatively low relative permittivity, the relative permittivity of at least one of the rim protector 24 and the sidewall core 16 decisively affects the transmission efficiency. Therefore, by setting the relative permittivity of the rim protector 24 and the sidewall core 16 within the aforementioned range, the transmission efficiency required for wireless power supply can be maintained. The relative permittivity of the sidewall tread 26 is preferably set to 4.0 or higher and 35 or lower, and extremely preferably to 4.5 or higher and 33 or lower. The relative permittivity of the rim protector 24 and the sidewall core 16 is preferably set to 75 or higher and 215 or lower, and extremely preferably to 80 or higher and 210 or lower. In addition, the dielectric loss tangent (tanδ) of the sidewall tread 26 is preferably 0.02 to 0.47, and the dielectric loss tangent (tanδ) of the rim protector 24 and the sidewall core 16 is preferably 0.6 to 1.4.

[0208] Figure 9 This is a radial cross-sectional view of the tire 10 in Additional Embodiment 6, showing the main portion of the tire 10, and illustrating the case where the tire 10 includes the second filler 25. In this case, the relative permittivity of the second filler 25 is preferably the same as that of the sidewall core 16. That is, the relative permittivity of the second filler 25 is preferably set to a range of 70 to 220, more preferably 75 to 215, and extremely preferably 80 to 210. Furthermore, the dielectric loss tangent (tanδ) of the second filler 25 is preferably 0.6 to 1.4.

[0209] (Additional Implementation Method 7)

[0210] Figure 10This is a radial cross-sectional view of the tire 10 showing the main part of the tire according to Additional Embodiment 7. In the basic embodiment 1 or the basic embodiment 1 with at least one of Additional Embodiments 2 to 3 added, it is preferable that, as shown in this figure, the receiving coil 40 generates electricity by receiving a magnetic field transmitted from a power supply coil disposed outside the tire in the tire width direction. In the radial cross-sectional view of the tire, in the radial region R1 of the receiving coil, whose radial length is defined by the length between the two ends of the receiving coil 40 in the tire radial direction, at least one of the sidewall core 16 and the rim protector 24 is disposed, with a relative permittivity in the range of 70 to 200, and no sidewall tread 26 is disposed. The relative permittivity of the sidewall tread 26 disposed outside the radial region R1 of the receiving coil in the tire radial direction is in the range of 3.5 to 40 (Additional Embodiment 7).

[0211] like Figure 10 As shown, in the additional embodiment 7, the tire 10 is configured such that the radial region R1 of the receiving coil overlaps with at least one of the sidewall core 16 and the rim protector 24 in the tire radial direction (in Figure 10 The indicated position is both the sidewall core 16 and the rim protector 24, and does not overlap with the sidewall tread 26. The radial region R1 of the receiving coil can also be configured to overlap with either the rim protector 24 or the sidewall core 16 in the tire radial direction. In Additional Embodiment 7, in Figure 10 In the positional relationship shown, the relative permittivity of the rim protector 24 and the sidewall core 16 is in the range of 70 to 200, and the relative permittivity of the sidewall tread 26 is in the range of 3.5 to 40.

[0212] According to Additional Embodiment 7, when only at least one of the rim protector 24 and the sidewall core 16 with relatively high relative permittivity is provided in the radial region R1 of the receiving coil, but the sidewall tread 26 is not provided, the transmission efficiency required for wireless power supply can be maintained by setting the relative permittivity of the rim protector 24 and the sidewall core 16 within the above-mentioned range. The relative permittivity of the rim protector 24 and the sidewall core 16 is preferably set to 75 or more and 195 or less, and extremely preferably to 80 or more and 190 or less. The relative permittivity of the sidewall tread 26 is preferably set to 4.0 or more and 38 or less, and extremely preferably to 4.5 or more and 36 or less. Furthermore, the dielectric loss tangent (tanδ) of the rim protector 24 and the sidewall core 16 is preferably 0.6 to 1.3, and the dielectric loss tangent (tanδ) of the sidewall tread 26 is preferably 0.02 to 0.50.

[0213] It should be noted that, in the presence of such Figure 3In the case of the tire 10 with the second filler 25 shown, the relative permittivity of the second filler 25 is preferably the same as that of the sidewall core 16. That is, the relative permittivity of the second filler 25 is preferably set to a range of 70 to 200, more preferably 75 to 195, and extremely preferably 80 to 190. Furthermore, the dielectric loss tangent (tanδ) of the second filler 25 is preferably 0.6 to 1.3.

[0214] (Additional Implementation Method 8)

[0215] In the basic embodiment 1 or in which at least one of the additional embodiments 2 to 7 is added, it is preferable that the difference in relative permittivity between each member disposed in the radial region WH of the tire and other members adjacent in the tire width direction is 170 or less (additional embodiment 8).

[0216] For example, along Figure 1 The single-dot line I-I' shown indicates that, starting from the inside in the tire width direction, the inner liner 12, tire body 18, sidewall tread 26, and wing tip 28 are arranged sequentially and adjacently. Furthermore, along... Figure 1 The single-dot line II-II' shown indicates that, starting from the inside in the tire width direction, the inner liner 12, tire body 18, and sidewall tread 26 are arranged sequentially adjacent to each other. Furthermore, along... Figure 1 The single-dot line III-III' shown indicates that, starting from the inside of the tire width direction, the inner liner 12, tire body 18, rim protector 24, and sidewall tread 26 are arranged sequentially and adjacently. Furthermore, along... Figure 3 The single-dot line IV-IV' shown includes, from the inside of the tire, the following components arranged sequentially and adjacently: inner liner 12, main body 18a of tire carcass 18, sidewall core 16, folded-back portion 18b of tire carcass 18, second filler 25, rim protector 24, and sidewall tread 26. The difference in relative permittivity between these adjacent components is all less than 170. More specifically, it includes components having… Figure 2 Including the configuration of the zero-pressure liner 32 shown, considering all combinations, the difference in relative permittivity between adjacent components can be expressed by the following inequality. It should be noted that the relative permittivity of the inner liner 12 is set as IL, the relative permittivity of the carcass 18 as C, the relative permittivity of the sidewall tread 26 as ST, the relative permittivity of the wing tip 28 as WT, the relative permittivity of the second filler 25 as 2FL, the relative permittivity of the sidewall core 16 as BFL, the relative permittivity of the rim protector 24 as RC, and the relative permittivity of the zero-pressure liner 32 as RFL. The relative permittivity of the inner liner 12 is the value of the entire component including the air-blocking layer and the adhesive rubber layer. Furthermore, the relative permittivity of the carcass 18 is the value of the entire component including the reinforcing fibers. The relative permittivity of the other components is the relative permittivity of the rubber layer of the component.

[0217] |IL-C|≤170

[0218] |ST-C|≤170

[0219] |ST-WT|≤170

[0220] |RC-C|≤170

[0221] |RC-ST|≤170

[0222] |C-BFL|≤170

[0223] |C-2FL|≤170

[0224] |ST-2FL|≤170

[0225] |RC-2FL|≤170

[0226] |IL-RFL|≤170

[0227] |C-RFL|≤170

[0228] If the difference in relative permittivity between adjacent components is large at the boundary surface of adjacent components, high-frequency magnetic field reflection will occur, reducing transmission efficiency. However, according to Additional Embodiment 8, since the difference in relative permittivity between adjacent components is 170 or less, the reflection of high-frequency magnetic field is suppressed, thereby suppressing the reduction in transmission efficiency. More specifically, even if the difference in relative permittivity between adjacent components is 170 or less, high-frequency electromagnetic waves will still be reflected at the boundary surface of adjacent components. However, in this case, the losses caused by eddy currents generated by the metal of the tire bead portion A and belt 20 are greater, so the reflection of high-frequency electromagnetic waves is relatively not a problem. Therefore, by setting the difference in relative permittivity between adjacent components to 170 or less, the problem can be limited to eddy current losses at the bead portion A and belt 20. Furthermore, by ensuring that all components in the radial region WH of the tire meet the above range, the degree of freedom in arranging the position of the receiving coil 40 is increased. The difference in relative permittivity between adjacent components is preferably set to 160 or less, and extremely preferably 150 or less. Furthermore, the difference in dielectric loss tangent (tanδ) between the relative permittivity of adjacent components is preferably 0.9 or less.

[0229] (Additional Implementation Method 9)

[0230] In the basic embodiment 1 or in which at least one of the additional embodiments 2 to 8 is added, it is preferred that the receiving coil 40 generates electricity by receiving a magnetic field transmitted from the sending coil disposed outside the tire in the tire width direction, and in a tire radial cross-sectional view, the difference in relative permittivity between the member of the radial region R1 of the receiving coil disposed in the tire radial direction and other members adjacent in the tire width direction is 165 or less (additional embodiment 9).

[0231] Since the components disposed in the radial region R1 of the receiving coil have a significant impact on power transmission efficiency, it is preferable that the difference in relative permittivity between adjacent components is smaller compared to components disposed radially outside the radial region R1 of the receiving coil. Therefore, it is preferable to satisfy the above-mentioned range. The difference in relative permittivity between adjacent components is preferably set to 155 or less, and extremely preferably 150 or less. Furthermore, the difference in dielectric loss tangent (tanδ) of the relative permittivity of adjacent rubber layers is preferably 0.88 or less.

[0232] (Additional Implementation Method 10)

[0233] In the basic embodiment 1 or the basic embodiment 1 with at least one of the additional embodiments 2 to 9, it is preferred that the conductive wire 43 of the receiving coil 40 is separated by a support layer 44 disposed on the surface of the inner liner 12 constituting the inner cavity surface of the tire, and in the radial region WH of the tire, the relative permittivity of the support layer 44 existing between the conductive wire 43 and the inner liner 12 is lower than the relative permittivity of the inner liner 12 (additional embodiment 10).

[0234] Figure 11 This is a radial cross-sectional view of the tire 10 in the additional embodiment 10, showing the main part of the tire 10. It is an enlarged view showing the current receiving coil 40 and its surrounding area provided on the surface of the inner liner 12 constituting the inner cavity surface of the tire by the spacer support layer 44. Figure 11 (A) shows an example in which the conductive wire 43 of the receiving coil 40 is separated from the insulating support layer 44 and disposed on the surface of the inner liner 12, and the conductive wire 43 is exposed in the inner cavity of the tire. Figure 11 (B) shows an example in which the conductive wire 43 of the current receiving coil 40 is separated by a support layer 44 disposed on the surface of the liner 12, and the conductive wire 43 is covered by the support layer 44. Figure 11 (C) represents an example in which the conductive wire 43 of the current receiving coil 40 is separated from the support layer 44 and disposed on the surface of the liner 12, and the conductive wire 43 is covered by a layer 46 different from the support layer 44.

[0235] exist Figure 11 (A) ~ Figure 11In any of (C), the support layer 44 is sandwiched between the conductive wire 43 and the inner liner 12, and the conductive wire 43 and the inner liner 12 are not in contact. Current caused by magnetic field resonance flows in the conductive wire 43, thereby generating a magnetic field around the conductive wire 43. However, the closer to the conductive wire 43, the greater the magnetic flux density, and the greater the influence of the relative permittivity of the component near the conductive wire 43 on magnetic field attenuation. According to Additional Embodiment 10, by separating the conductive wire 43 from the inner liner 12 and providing a support layer 44 with a lower relative permittivity between the inner liner 12 and the conductive wire 43, magnetic field attenuation can be suppressed. The support layer 44 and another layer 46 are made of an insulating material, such as rubber, resin, etc.

[0236] (Additional Implementation Method 11)

[0237] Figure 12 This is a radial cross-sectional view of the tire 10 in the additional embodiment 11, showing the main part of the tire 10. It is an enlarged view showing the current receiving coil 40 and its surrounding area provided on the surface of the inner liner 12 of the tire cavity by the spacer support layer 44. Figure 12 (A) and Figure 11 (A) Similarly, an example is shown in which the conductive wire 43 of the receiving coil 40 is separated from the insulating support layer 44 and disposed on the surface of the inner liner 12, and the conductive wire 43 is exposed in the inner cavity of the tire. Figure 12 (B) represents an example where the support layer 44 is embedded in the liner 12. Dmin in equation (1) is... Figure 12 (A) and Figure 12 (B) shows the shortest distance from the conductive line 43 of the current receiving coil 40 to the inner liner 12.

[0238] In the basic embodiment 1 or in which at least one of additional embodiments 2 to 10 is added, it is preferable that the receiving coil 40 generates electricity by receiving a magnetic field transmitted from a power supply coil disposed outside the tire in the tire width direction. In a tire meridian cross-sectional view, the relative permittivity εr of each component on a virtual line in the tire width direction at any position within the radial region R1 of the receiving coil is... k Thickness G in the tire width direction k The sum of the products (mm) (k=1 to n (n is the number of components on the virtual line)) and the relationship with the shortest distance Dmin from the conductive line 43 of the current receiving coil 40 to the inner liner 12 are within the range of Equation (1) (Additional Embodiment 11). The relative permittivity of the inner liner 12 is the value of the entire component including the air blocking layer and the adhesive rubber layer. In addition, the relative permittivity of the tire body 18 is the value of the entire component including the fiber cords, etc., which serve as reinforcements. The thickness of the inner liner 12 and the tire body 18 is set to the thickness of the component itself.

[0239] [Formula 3]

[0240]

[0241] The inventors first discovered that the relative permittivity εr of each component on the aforementioned virtual line... k Thickness G in the tire width direction k The larger the sum of the products (mm), the greater the magnetic field attenuation. Furthermore, as mentioned above, the current caused by magnetic field resonance flows in the conductive line 43, but the closer to the conductive line 43, the greater the magnetic flux density, and the greater the influence of the relative permittivity of the support layer 44 near the conductive line 43 on the magnetic field attenuation. Therefore, the inventors discovered the relationship in equation (1) based on the following insight: if the thickness (shortest distance Dmin) of the support layer 44 is small, then even if the relative permittivity εr of each component is small... k Thickness G in the tire width direction k The sum of the products of (mm) is large, which can also suppress the attenuation of the magnetic field.

[0242] According to the additional embodiment 11, the attenuation of the magnetic field passing through the tire 10 is suppressed, and the loss of the magnetic field formed around the conductive wire 43 is also suppressed, thereby maintaining a high transmission efficiency. If the value of Σ / Dmin in equation (1) is less than 200, the shortest distance Dmin will become too large, the support layer 44 will become thicker, thereby increasing the tire mass, or the thickness G of each component will increase. k If the value of ∑ / Dmin is too small, the rigidity of tire 10 cannot be adequately obtained. Furthermore, if the value of ∑ / Dmin is greater than 6000, the shortest distance Dmin is too small, causing the liner 12 to be close to the conductive wire 43, resulting in increased magnetic field attenuation, or the thickness G of each component... k If the value is too large, the attenuation of the magnetic field will increase. Therefore, it is preferable to satisfy the range of equation (1). The relative permittivity εr of each component k Thickness G in the tire width direction k The sum of the products of (mm) divided by the shortest distance Dmin is preferably 250 to 5500, and most preferably 300 to 5000.

[0243] (Additional Implementation Method 12)

[0244] In the manner of basic implementation 1 or basic implementation 1 incorporating at least one of additional implementations 2 to 11, it is preferred that, as Figure 2 As shown, a sidewall support layer (zero-pressure liner 32) is provided inside the tire width direction of the tire body 18. The relative permittivity of the sidewall support layer (rubber material) is in the range of 8 to 90, and is lower than that of the one with a higher relative permittivity, the rim protector 24 and the sidewall core 16 (rubber material) (Additional Embodiment 12).

[0245] Additional implementation method 12 corresponds to Figure 2 The configuration is shown. Since the zero-pressure liner 32 is arranged throughout the radial region WH of the tire, the receiving coil 40 is arranged close to the zero-pressure liner 32. The greater the thickness t of the zero-pressure liner 32, the greater its influence on magnetic field attenuation. According to Additional Embodiment 12, the rubber layer arranged around the receiving coil 40 consists of the inner liner 12, the tire body 18, and the zero-pressure liner 32. The receiving coil 40 is separated from the rim protector 24 and the sidewall core 16. Therefore, if the relative permittivity of the zero-pressure liner 32 is lower than that of the rim protector 24 and the sidewall core 16, the sidewall portion B will become thicker due to the zero-pressure liner 32, which can mitigate the degree of magnetic field attenuation caused by this. The relative permittivity of the rubber material constituting the zero-pressure liner 32 is preferably set to the range of 8.5 to 85, and extremely preferably to 9 to 80 or less. Furthermore, the difference in dielectric loss tangent (tanδ) of the zero-pressure liner 32 is preferably 0.06 or more and 0.8 or less.

[0246] (Additional Implementation Method 13)

[0247] In additional embodiment 12, it is preferred that, for example, in Figure 2 In the radial cross-sectional view of the tire shown, within the radial region R1 of the coil receiving coil 40, whose radial length is defined by the length between the two radial ends of the coil receiving coil 40, the maximum value of the thickness t in the tire width direction of the sidewall support layer (zero-pressure liner 32) is in the range of 4 to 12 mm (Additional Embodiment 13). If the thickness t of the zero-pressure liner 32 is greater than 12 mm, the heat generated by the zero-pressure liner 32 during driving increases, thereby hindering the heat dissipation of the coil receiving coil 40. If the thickness t of the zero-pressure liner 32 is greater than 12 mm, the effect on magnetic field attenuation increases. Furthermore, by setting the thickness t of the zero-pressure liner 32 to 4 mm or more, the coil receiving coil 40 can be separated from the rim protector 24 and the sidewall core 16, which have a higher relative permittivity, thus reducing the impact on transmission efficiency and achieving both puncture resistance and safety. Therefore, the maximum value of the thickness t in the tire width direction of the zero-pressure liner 32 is preferably in the range of 4 to 12 mm. The maximum value of the tire width direction thickness t of the zero-pressure liner 32 is preferably set to the range of 4.5 to 11.5, and extremely preferably to be 5 to 11 or less. In addition, the dielectric loss tangent (tanδ) of the zero-pressure liner 32 is preferably 0.06 to 0.8.

[0248] <Wireless Power Supply System>

[0249] [Basic Implementation Method 14]

[0250] Figure 13This diagram shows the power transmission coil 52 in the wireless power supply system 50 of this embodiment, and the tire 10 (on the tire width direction relative to the tire equatorial plane CP in the tire radial cross-sectional view) equipped with the power receiving coil 40. It should be noted that this diagram shows the tire portion opposite to the contact patch when assembled to the rim and subjected to normal internal pressure and a load of 80% of the normal load (this also applies to the invention of the wireless power supply system below). It should be noted that the power transmission coil 52 shown in this diagram is a coil with the tire width direction as its winding axis, but particularly regarding the portion extending in its tire radial direction, it may extend only in the tire radial direction, or it may extend in at least one of the other tire circumferential and tire width directions.

[0251] The power supply coil 52 shown in the figure consists of a capacitor and a coil forming a resonant circuit, for example, mounted on the tire side surface of the steering knuckle, which is a steering shaft component of a vehicle not shown.

[0252] In contrast, Figure 13 The power receiving coil 40 shown is Figure 1 The receiving coils shown are identical in configuration, forming a resonant circuit with a capacitor and a coil. It should be noted that... Figure 13 The tire 10 shown is a tire of the basic embodiment 1 related to the above-described tire 10, and a tire of the basic embodiment 1 incorporating at least one of the additional embodiments 2 to 13, the function of which is as described above.

[0253] Under this premise, the wireless power supply system 50 of this embodiment uses a magnetic field resonance method for wireless power supply, such as... Figure 13 As shown, power is supplied to the transmitting coil 52, and power is transmitted to the receiving coil 40 via an alternating magnetic field. According to this wireless power supply system 50, as described above, power supply efficiency can be improved.

[0254] Here, in order to drive the sensors and associated circuits installed in the tire 10, it is preferable to supply 0.1 to 15 W of power at a frequency of 1 to 20 MHz. More preferably, AC power at a frequency of 6.78 to 13.56 MHz is supplied to the power supply coil 52.

[0255] Furthermore, the shortest distance between the transmitting coil 52 and the receiving coil 40 (hereinafter sometimes referred to as "transmission gap G") is preferably 10 mm to 80 mm. Here, the transmission gap G is set as a value measured when the tire 10 is assembled on the rim and a normal internal pressure is applied, mounted on the vehicle, and stopped on level ground. Furthermore, the transmission gap G refers to... Figure 13 The shortest distance between the transmitting coil 52 and the receiving coil 40, i.e. Figure 13The distance between the innermost position of the transmitting coil 52 in the tire width direction and the outermost position of the receiving coil 40 in the tire width direction.

[0256] By setting the transmission gap G to 10mm or more, it is possible to suppress the influence of [something] in the direction of power transmission. Figure 13 The large rate of change in the received power caused by the relative positional variation of the transmitting coil 52 and the receiving coil 40 simplifies the circuit configuration connected to the receiving coil 40, thereby enabling the easy supply of stable power to electronic devices. Here, the variation in received power depends on the slight expansion of the tire 10 due to centrifugal force during tire 10 rolling, causing a change in the relative position between the two coils 52 and 40. Specifically, the faster the tire rolls, the more the receiving coil 40 will move radially outward due to the radial expansion of the tire 10. Figure 13 The upper side of the coil 52 moves, while the position of the power supply coil 52 remains unchanged. Therefore, the relative positions between the two coils 52 and 40 change.

[0257] In contrast, by setting the transmission gap G to less than 80mm, the strength of the magnetic field generated between the two coils 52 and 40 will not become too small, thus enabling efficient power supply based on electromagnetic induction.

[0258] It should be noted that the transmission gap G is preferably 12mm or more and 75mm or less, and extremely preferably 15mm or more and 70mm or less.

[0259] By employing the transmission gap G range, power range, and frequency band as described above, not only can the temperature rise of the receiving coil 40 be suppressed, but also power can be efficiently supplied without increasing the number of coil turns (and thus without increasing the coil weight), without increasing the rolling resistance of the tire, thereby achieving excellent transmission efficiency. Furthermore, especially when using a tire structure to transmit power in wireless power supply via magnetic resonance in the aforementioned frequency band, based on the aforementioned transmission gap G range, excellent power supply efficiency can be obtained.

[0260] [Additional Implementation Method 15]

[0261] Figure 14 The diagram shows the overlap pattern of the tire radial position of the power supply coil 52 and the tire radial position of the power receiving coil 40 in the wireless power supply system 50 of this embodiment. (A) shows an example where the outer radial portion of the power supply coil 52 overlaps with the inner radial portion of the power receiving coil 40. (B) shows an example where the inner radial portion of the power supply coil 52 overlaps with the outer radial portion of the power receiving coil 40.

[0262] In basic implementation 14, it is preferable that, as Figure 14As shown in (A) and (B), in the radial cross-sectional view of the tire, at least a portion of the receiving coil 40 is located within a power supply area extending along the winding axis of the sending coil 52, between both ends of the sending coil 52 in the longitudinal direction (Additional Embodiment 15). Here, the positional relationship between the receiving coil 40 and the sending coil 52 in the radial direction of the tire is measured with the tire 10 assembled on the rim and with normal internal pressure applied, mounted on the vehicle, and stopped on level ground.

[0263] In the wireless power supply system 50 of this embodiment, the power supply coil 52 is mounted on the tire side surface of the steering knuckle or wheel hub frame (located outside the tire width direction of the sidewall portion B), which is a steering axle component of the vehicle, or any component constituting the strut structure. Therefore, considering the shape of the tire 10, especially the sidewall portion B, when studying power supply efficiency, it is ideal that... Figure 14 As shown in (A) and (B), the direction of the magnetic field line passing through the tire at the sidewall B, and thus the power supply direction Dp, is set to approximately the tire width direction.

[0264] According to this view, such as Figure 14 As shown in (A) and (B), when the power supply direction Dp is set to approximately the tire width direction, power supply can be delivered more efficiently, thereby achieving excellent transmission efficiency.

[0265] In addition, Figure 14 In the examples shown in (B) and (C), regarding each transmitting coil 52 and receiving coil 40, due to the constituting surface (in Figure 14 (B) and (C) are planes whose normals are the winding axes of each coil, and therefore are parallel to each other. Figure 14 Compared to the examples shown in (A) and (D), it can provide power more efficiently, thereby achieving excellent transmission efficiency.

[0266] It should be noted that, as Figure 14 As shown in (A) and (D), the surfaces of the transmitting coil 52 and the receiving coil 40 do not need to be parallel to each other. This is because if the magnetic field generated by the transmitting coil 52 links with the receiving coil 40, an electromotive force will be generated through electromagnetic induction, and there are no restrictions on the relative orientation of the surfaces.

[0267] [Additional Implementation Method 16]

[0268] Figure 15 This is a diagram showing the installation position of the power transmission coil 52 in the wireless power supply system 50 of this embodiment.

[0269] In the basic implementation method 14 or the basic implementation method 14 with the addition of the additional implementation method 15, it is preferred that, as Figure 15As shown, the power supply coil 52 is disposed within a range of 60° on both sides of the tire circumference centered on a virtual line extending vertically upward from the tire center O (Additional Embodiment 16).

[0270] Normally, when the tire 10 rolls, the current-receiving coil 40 at the ground contact portion of the tire 10 also deforms along with the deformation of the ground contact portion. On the other hand, at the portion of the tire 10 away from the ground contact portion ( Figure 15 The deformation of the receiving coil 40 due to tire deformation is almost invisible (located on the upper part of the tire 10). Therefore, by placing the power supply coil 52, which is disposed on the outside of the tire 10, near the upper part of the tire (within a 60° circumferential range on both sides of a virtual line extending vertically upward from the tire center O), the variation of the transmission gap G can be suppressed when the tire rolls, enabling more efficient power supply and thus achieving superior transmission efficiency. It should be noted that... Figure 15 The example shown is an example of mounting the power supply coil 52 on the wheel cover 54, within which the above-mentioned tire circumferential range applies.

[0271] It should be noted that the power supply coil 52 is preferably located within a 55° circumferential range on both sides of the virtual line extending vertically upward from the center of the tire, and most preferably within a 50° circumferential range on both sides of the virtual line.

[0272] Furthermore, the shape of the power supply coil 52 is not particularly limited, but when the power supply coil 52 is placed inside, for example, a wheel cover, it is preferable to make a so-called spiral coil that can reduce the overall thickness.

[0273] [Additional Implementation Method 17]

[0274] Figure 16 and Figure 17 It means in Figure 1 The diagram shows the location of the power supply coil in the tire.

[0275] In the basic embodiment 14 or the basic embodiment 14 with at least one of the additional embodiments 15 and 16, it is preferred that the power supply coil 52 is disposed on the unsprung member of the vehicle (additional embodiment 17).

[0276] Unsprung components include, for example, steering knuckles, brake calipers, and damper housings of strut suspensions. By providing a power supply coil 52 on the unsprung component, the distance between the power supply coil 52 and the power receiving coil 40 provided on the tire 10 can be kept constant even when the vehicle moves up and down due to road surface irregularities.

[0277] like Figure 16 (A) and Figure 16As shown in (B), the power supply coil 52 can be mounted on the damper housing 60 of the strut suspension. Figure 16 (A) shows an example in which the power supply coil 52 is disposed in the damper housing 60 of the front wheel. Figure 16 (B) shows an example where the power supply coil 52 is disposed in the damper housing 60 of the rear wheel. Therefore, even when the tire 10 moves up and down due to road surface irregularities, the power supply coil 52 can be positioned opposite the power receiving coil 40 in the tire width direction, bypassing the belt and bead core, to transmit power in the tire width direction. Thus, the wireless power supply system 50 can improve power supply efficiency.

[0278] Alternatively, the power supply coil 52 can be installed on components such as the steering knuckle of a multi-link suspension that move together with the tire 10 in conjunction with the steering. Figure 17 The front wheel of the multi-link suspension has a steering knuckle 70 that is linked to the steering mechanism and rolls relative to the upper arm 72 along with the tire 10. This allows the distance between the power supply coil 52 and the power receiving coil 40 located on the tire 10 to remain constant, even during steering. Therefore, the tire 10 can be stably powered while driving.

[0279] <Other methods regarding tires and wireless power systems>

[0280] The above is a description of the tire and wireless power supply system of the present invention. Other matters concerning the tire and wireless power supply system of the present invention are listed below.

[0281] Preferably, as Figure 1 The carbon content of the inner liner 12 of the tire 10 shown is 45 to 75 parts by weight (assuming 100 parts of rubber, the same below), the carbon content of the sidewall tread is 25 to 65 parts by weight, the carbon content of the rim protector is 60 to 90 parts by weight, the carbon content of the sidewall core 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 zero-pressure liner is 45 to 75 parts by weight. By using these proportions of each component, the desired relative permittivity can be achieved in each rubber layer, and the aforementioned tire performance can be achieved. It should be noted that, generally, the relative permittivity of rubber is determined by the polymer type and compounding agents. Adjusting the carbon content easily changes the electrical properties (due to the high conductivity of carbon particles themselves) and easily balances the rubber properties required for the tire, therefore it is the most preferred method.

[0282] about Figure 13 The wireless power supply system 50 shown is preferably configured such that the receiving coil 40 is disposed in the tire cavity of the sidewall portion B of the tire 10 with the receiving surface facing the tire width direction. As described above, Figure 14As shown in (a) and (b), when the transmission direction determined by the power supply coil 52 is set to approximately the tire width direction, the power supply surface of the power supply coil 52 is parallel to the power receiving surface of the power receiving coil 40 by setting the power receiving surface of the power receiving coil 40 to face the tire width direction. This allows for more efficient power supply and thus achieves superior transmission efficiency.

[0283] Figure 18 This indicates the configuration of the receiving coil 40 (and...). Figure 6 (A) Similarly, the current receiving coil 40 is discontinuous in the tire circumferential direction. (A) to (F) are examples of current receiving coils 40 consisting of 2, 3, 4, 5, 6 and 8 sets of current receiving coil elements 40a, respectively. (G) is an example of multiple current receiving coil elements 40a being stacked in the tire radial direction. (H) is an example of a portion of multiple current receiving coil elements 40a extending obliquely relative to the tire radial direction.

[0284] like Figure 18 As shown in (A) to (H), the receiving coil 40 can also be formed by multiple receiving coil elements 40a. During tire rolling, the inner surface of the tire where the receiving coil 40 is located repeatedly deforms and releases the tire 10. When a single receiving coil 40 is positioned around the entire circumference of the tire 10, during tire rolling, the coil 40 has a deformed and skewed portion (near the ground contact portion of the tire 10) and an undeformed portion (the upper part of the tire 10), making it easy for the receiving coil 40 to peel off from the inner surface of the tire. Therefore, by dividing the tire circumference into multiple regions and arranging the receiving coil elements 40a in each of these regions, it is possible to suppress the peeling of the receiving coil 40 from the inner surface of the tire.

[0285] Figure 19 It means in Figure 1 The tire shown is a radial cross-sectional view of the tire 10 in which power is supplied from the receiving coil 40 to the electronic device 47 mounted on the inner surface of the tire via the power line 45 (however, it is half in the tire width direction).

[0286] As shown in the figure, the receiving coil 40 is connected to a capacitor (not shown) that serves as a resonant circuit, and then supplies power to electronic devices 47 (sensors, signal processing circuits, communication channels, etc.) mounted on the inner surface of the tire via power lines 45 mounted on the inner surface of the tire. Compared to the receiving coil 40, the electronic devices 47 have lower durability against deformation; however, even when placed near the belt 20, which is a magnetic material, they do not cause obstacles due to the magnetic field. Therefore, the electronic devices 47 are also positioned on the inner surface of the tire 10 in the tire's width direction region where the belt 20 is formed, where rigidity is high, while the receiving coil 40 is positioned on the inner surface of the tire's sidewall portion B, which improves power supply efficiency. The two are wiredly connected by the power lines 45. This allows the power received by the receiving coil 40 to be supplied to the electronic devices 47 with less loss and higher power supply efficiency, while ensuring the durability of the electronic devices 47. Furthermore, by arranging all these components (current receiving coil 40, capacitor, power line 45, and electronic device 47) on the inner surface of the tire, the increase in manufacturing cost and manufacturing difficulty of the tire 10 is suppressed.

[0287] 2. Second Implementation Method

[0288] Hereinafter, a second embodiment of the tire of the second invention (basic embodiment 2 and additional embodiments 18-22 shown below) will be described in detail with reference to the accompanying drawings. It should be noted that the second embodiment does not limit the present invention. Furthermore, the constituent elements of the second embodiment include elements that can be easily replaced by those skilled in the art, or substantially the same elements. Moreover, the second embodiment can be arbitrarily combined within the scope that is obvious to those skilled in the art.

[0289] [Basic Implementation Method 2]

[0290] The same reference numerals are used for components that are the same as those in the first embodiment described above, and the descriptions are omitted. Figure 1 This is a meridian cross-sectional view of one side of the tire width direction, with the tire equatorial plane (not shown) as the reference. It should be noted that this figure shows the tire portion on the side opposite to the contact patch when it is assembled to the rim and subjected to normal internal pressure and normal load (hereinafter, the same applies to the invention of the tire).

[0291] like Figure 20As shown, the tire 10A of this embodiment has a bead portion A, a sidewall portion B, a shoulder portion C, and a tread portion D extending radially from the inner side of the tire to the outer side. An inner liner 12 exposed to the inner surface of the tire is provided in the area from the bead portion A to the tread portion D. A tire body 18 is provided on the side of the inner liner 12 opposite to the inner surface of the tire. The tire body 18 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 sidewall core 16. On the radial outer side of the tire body 18 at the tread portion D, a belt 20 (belt layers 20a, 20b) and a belt cover 22 (belt cover layers 22a, 22b) are sequentially provided radially outward.

[0292] Furthermore, a rim protector 24 is provided further outward in the tire width direction of the folded-back portion 18b of the tire carcass 18, which is located on the outer side of the bead core 14 and the sidewall core 16. A second filler 25 is provided between the rim protector 24 and the folded-back portion 18b. A sidewall tread 26, a wing tip 28, and a crown 30 are sequentially provided on the outer radial side of the rim protector 24. A bead reinforcement layer 31 is provided in the bead portion A, which folds back at the toe 33 from the inner circumference of the tire and extends to the radial middle portion of the sidewall core 16 on the outer circumference of the tire.

[0293] In the tire 10A configured as shown above, the inner liner 12 is a layer used to block gas from contacting the inner surface of the tire. The inner liner 12 may consist of a single inner liner layer or multiple inner liner layers stacked radially along the tire equatorial plane CP. The inner liner 12 includes at least one layer made of low-permeability rubber or a layer made of resin, and may include an adhesive layer as an additional layer at least in the contact portion with the tire carcass 18.

[0294] The bead core 14 is, for example, an annular reinforcement formed by bundling cords, and can be configured as a structure in which rubber is used to cover the area around multiple bead wires made of steel cords or organic fiber cords. The sidewall core 16 is a component used to improve the rigidity of the bead portion A, and can be configured as follows: Figure 20 The approximate triangular shape shown has a tire width dimension at the inner radial end of the tire and a tire width dimension at the outer radial end of the tire bead core 14 that are approximately equal, and the tire width dimension gradually decreases towards the outer radial direction of the tire.

[0295] The carcass 18 is a component forming the skeleton of the tire 10A, and is composed of at least one carcass layer (carcass ply), each carcass layer having a structure in which multiple carcass cords are covered with rubber. Typically, steel cords or organic fiber cords are used as carcass cords. However, in the tire 10A of this embodiment, as described later, in order to prevent the magnetic field generated in the sidewall portion B, which penetrates substantially perpendicularly through the tire's inner cavity surface of the inner liner 12, from being obstructed by the metal component, it is preferable to use a non-magnetic material as the carcass cord. For example, organic fibers such as rayon, polyester, polyamide, and aramid can be used as non-magnetic materials.

[0296] The belt 20 is a reinforcing layer disposed on the radially outer side of the tire carcass 18. It is a component that secures the tire carcass 18, increases the rigidity of the tread portion, thereby improving driving stability, and reduces rolling resistance by decreasing strain deformation. The belt 20 can be composed of multiple belt layers stacked radially along the tire tread portion D. Figure 20 The example shown consists of two bundle layers 20a and 20b. Each bundle layer 20a and 20b is composed of multiple bundle cords covered with rubber. Typically, steel cords or organic fiber cords are used as bundle cords. As bundle cords, it is natural to use magnetic materials such as steel cords, but non-magnetic materials (including paramagnetic and diamagnetic materials) can also be used.

[0297] The belt cover 22 is a component that enhances the securing effect of the belt 20 to the tire carcass 18, particularly for preventing deformation of the tread portion D due to centrifugal forces generated during high-speed vehicle operation. The belt cover 22 can be composed of multiple belt cover layers stacked radially outward from the tire on the radial side of the belt 20. Figure 20 The example shown consists of two belt cover layers 22a and 22b. Each belt cover layer 22a and 22b has a structure in which multiple cords are covered with rubber. Typically, steel cords or organic fiber cords are used as the cords used in the belt cover layers. As the cords, it is natural to use magnetic materials such as steel cords, but non-magnetic materials (including paramagnetic and antimagnetic materials) can also be used. The bead reinforcement layer 31 is a component that wraps around the folded-back portion 18b of the tire carcass 18 to help improve the rigidity of the bead portion A, and it has a structure in which multiple cords made of steel cords are covered with rubber. The tire 10A has a second tire carcass 29 between the folded-back portion 18b of the tire carcass 18 and the bead reinforcement layer 31. The second tire carcass 29 extends from the toe 33 to the tread portion D.

[0298] A rim protector 24 is disposed in the area contacting the rim flange of a wheel (not shown), and a sidewall tread 26 is configured to connect the rim protector 24 to the tread portion D. In a radial sectional view of the tire, winglets 28 are respectively disposed at the boundaries of the tread portion D and the sidewall tread 26 on the left and right sides of the tire, and a crown 30 is formed on the surface of the tread portion D in a manner that covers the entire area of ​​the tire contact patch. A second filler 25 is made of a different rubber than the rim protector 24 and, as shown in the example, is positioned adjacent to the folded-back portion 18b of the tire carcass 18. By providing the second filler 25, the rigidity of the sidewall portion B can be moderately improved. It should be noted that the rim protector 24, the second filler 25, the sidewall tread 26, the winglets 28, and the crown 30 can all use conventionally used rubber components according to their respective required characteristics.

[0299] Assuming that the tire 10A described above has constituent elements 12 to 30, the tire 10A of this embodiment has a receiving coil 40 on the inner side of the tire cavity surface in the tire width direction. Figure 20 The receiving coil 40 receives alternating current from a power supply coil (not shown) disposed outside the tire 10A. The receiving coil 40 can be disposed in contact with the inner liner 12, or it can be embedded in the inner liner 12. Furthermore, the receiving coil 40 can also be configured to be fixed to the inner liner 12 via a fixing member other than rubber (e.g., made of a non-magnetic material, especially a rubber with relatively high thermal conductivity such as silicone rubber for the fixing part). Figure 20 ).

[0300] In the power supply of the tire 10A using this embodiment, a direct current obtained from a vehicle battery (not shown) is temporarily converted into an alternating current by an AC power supply device, and this alternating current is applied to a power supply coil (e.g., mounted on the tire side surface of the steering knuckle, which is a component of the vehicle's steering shaft), thereby generating an alternating magnetic field around the power supply coil. This alternating magnetic field links with the receiving coil 40, thereby generating an induced electromotive force in the receiving coil 40 to supply power.

[0301] In achieving such power supply, in the tire 10A of this embodiment, in the tire radial section view ( Figure 20 In this configuration, the receiving coil 40 is disposed in the radial region WH of the tire, from the outermost radial position P1 of the bead core 14 to the innermost radial position P2 of the belt 20. Furthermore, the receiving coil 40 is disposed in the region outside the tire width direction starting from the innermost radial position P2.

[0302] More specifically, the tire radial region WH is the tire radial region defined by the outer radial end of the bead core 14 (point P1), which may contain a strong magnetic material, and the innermost radial position of the belt 20 (point P2, the outer radial end of the belt 20 in the tire width direction), which may contain a strong magnetic material. It is a region further radially outer than point P1 and further radially inner than point P2. It should be noted that in the tire radial region WH, the tire 10A is curved in an outwardly convex shape. Therefore, if the current receiving coil 40 is provided in the tire radial region WH, the current receiving coil 40 is generally positioned further radially outer than the outer radial end of the belt 20 in the tire width direction (point P2). However, if point P1 is clearly located further radially inner than point P2, and the current receiving coil 40 is positioned near the bead core 14, it is possible that the current receiving coil 40 is positioned further radially inner than the width end of the belt 20 (point P2). Furthermore, if point P1 is located significantly further outward in the tire width direction than point P2, and the power receiving coil 40 is positioned near the belt 20, there may be a situation where the power receiving coil 40 is positioned further inward in the tire width direction than the radially outer end (point P1) of the bead core 14.

[0303] The tire sidewall refers to the externally visible tire surface on the side opposite to the tire's inner cavity surface within the tire's radial region WH. The outer rubber layer exposed on the tire sidewall contains an anti-aging agent at 0.5 to 8.0 parts by weight relative to 100 parts by weight of the rubber, and contains wax at 0.1 to 5.0 parts by weight relative to 100 parts by weight of the rubber. In this embodiment, the outer rubber layer exposed on the tire sidewall includes a rim protector 24, a sidewall tread 26, and a wing tip 28. That is, at least a portion of each of the rim protector 24, sidewall tread 26, and wing tip 28 is exposed on the tire sidewall, contains an anti-aging agent at 5.0 to 8.0 parts by weight relative to 100 parts by weight of the rubber, and contains wax at 0.1 to 5.0 parts by weight relative to 100 parts by weight of the rubber.

[0304] Generally, rubber can deteriorate and crack when exposed to ultraviolet light and oxygen atmospheres. To address this, rubber can be treated by containing anti-aging agents and waxes to inhibit deterioration and crack formation.

[0305] Tire 10A contains an anti-aging agent of 0.5 parts by mass or more relative to 100 parts by mass of rubber and a wax of 0.1 parts by mass or more relative to 100 parts by mass of rubber, thereby inhibiting the deterioration and cracking of rubber. On the other hand, tires containing anti-aging agents and waxes of 8.0 parts by mass or less relative to 100 parts by mass of rubber and 5.0 parts by mass or less relative to 100 parts by mass of rubber, respectively, can inhibit the precipitation of anti-aging agents and waxes on the tire sidewalls due to years of use.

[0306] The anti-aging agent is preferably an amine-based anti-aging agent. Examples of anti-aging agents include alkylated diphenylamine, 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, N,N'-diphenyl-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, N-phenyl-N'-1,3-dimethylbutyl-p-phenylenediamine, p-(p-toluenesulfonamide)diphenylamine, and N-phenyl-N'-(3-methacryloyloxy-2-hydroxypropyl)-p-phenylenediamine.

[0307] The content of anti-aging agents can be determined, for example, by gas chromatography according to JIS K6229 and JIS K0114, as follows: A brand new, unused tire is disassembled, and the outer rubber layer is cut into thin slices. These slices are then cut into test pieces approximately 1 mm square and 30 mm in length. The samples are extracted with acetone for 8 hours, and the resulting filtrate is allowed to return to room temperature to prepare the gas chromatographic sample. Furthermore, four solutions (standard samples) are prepared, each containing an anti-aging agent concentration ranging from 100 ppm to 1000 ppm. The area of ​​the resulting gas chromatographic sample is then calculated, and the content of the anti-aging agent in the sample is determined based on the calibration curve.

[0308] Wax is a substance that is malleable at ambient temperature, has relatively low viscosity when molten, is insoluble in water, and is hydrophobic. Examples of waxes include: petroleum-based waxes such as paraffin wax and microcrystalline wax; natural waxes such as plant-based waxes and animal-based waxes; and synthetic waxes such as polymers of ethylene and propylene. These waxes can be used alone or in combination of two or more.

[0309] The wax content can be determined, for example, according to JIS K6229, as follows: A brand new, unused tire is disassembled, and the outer rubber layer is cut into thin slices. These slices are then cut into test pieces approximately 1 mm square and 30 mm in length. Acetone is used for extraction for 8 hours, and the resulting filtrate is cooled (temperature <0°C) to allow the wax to precipitate. The wax content is then determined based on the weight of the precipitated wax and the weight of the test sample.

[0310] (Functions, etc.)

[0311] As described above, a wireless power receiving system that supplies power between a power transmission coil buried near the road surface and a power receiving coil mounted on the centerline of the tire width direction of a wheel is previously known (Patent Document 1, Figure 20 In this wireless power receiving system, the magnetic field from the transmitting coil to the receiving coil can sometimes be affected by the belt bundle. For example, in this wireless power receiving system, if the belt bundle uses a metallic (magnetic material only) belt cord, a portion of the magnetic field that should have reached the receiving coil from the transmitting coil is blocked by the magnetic material (belt cord) contained in the belt bundle, which may prevent the achievement of excellent power supply efficiency.

[0312] Therefore, the inventors have repeatedly conducted in-depth research on the following tire 10: even when Figure 20 When the belt 20 shown uses a metal belt cord, a portion of the magnetic field that should reach the receiving coil 40 from the power supply coil is not blocked by the tire 10, which contains magnetic material between the two coils, thereby achieving excellent power supply efficiency.

[0313] Specifically, the inventors have conducted in-depth research on the optimal position of the receiving coil 40, which is located inside the tire width direction of the inner cavity surface of the tire 10, relative to the power supply coil (not shown) located outside the tire 10.

[0314] First, the inventors et al. Figure 20 By focusing on multiple line segments that reach the tire's outer surface from each point (starting point) on the inner surface of the tire with the shortest distance, the following insights were derived: by extracting a region consisting of multiple line segments that do not contain the belt 20 from these line segments, and setting the receiving coil 40 in a manner that does not deviate from the inner surface of the tire contained in the region, most of the magnetic field generated between the two coils will not be blocked by the belt 20, which may contain magnetic material.

[0315] Next, considering that the above-mentioned insights are for defining the radially outer end of the tire in the area where the receiving coil 40 is installed, the inventors further investigated the radially inner end of the tire that defines this area. As a result, the inventors, focusing on the bead core 14 which may be made of a metal component, also concluded that by extracting an area composed of multiple line segments that do not include the bead core 14, and installing the receiving coil 40 in a manner that does not detach from the inner surface of the tire cavity contained in that area, most of the magnetic field generated between the two coils will not be blocked by the bead core 14, which may contain magnetic material.

[0316] Based on the above insights, in the tire 10 of this embodiment, the receiving coil 40 is disposed in the radial region WH of the tire, from the outermost radial position P1 of the bead core 14 to the innermost radial position P2 of the belt 20. Therefore, according to the tire 10 of this embodiment, since there is no excessive arrangement of tire 10 components that may contain magnetic materials between the supply coil and the receiving coil 40, the power supply efficiency can be improved.

[0317] Subsequently, during tire rolling, the use of the brakes generates iron dust from the brake discs and brake pads. In wireless power receiving systems, this iron dust can disrupt a portion of the magnetic field that should flow from the transmitting coil to the receiving coil. Therefore, methods to suppress the effects of iron dust generated from the brake discs and brake pads on the power receiving system have been extensively studied.

[0318] Specifically, the inventors have come to the following conclusion: due to changes over the years, the anti-aging agents and waxes contained in the rubber of the tire will precipitate out onto the tire surface, and iron powder generated from the brake disc and brake pads can easily adhere to the precipitated anti-aging agents and waxes.

[0319] Based on the above understanding, in the tire 10 of this embodiment, the anti-aging agent and wax contained in the outer rubber are limited to 0.5 to 8.0 parts by weight and 0.1 to 5.0 parts by weight, respectively, relative to 100 parts by weight of the rubber. By keeping the content of antioxidants and waxes in the outer rubber within the above ranges, the tire 10 can maintain the performance of the outer rubber while suppressing the amount of antioxidants and waxes precipitated. Therefore, according to the tire 10 of this embodiment, since the amount of antioxidants and waxes precipitated on the tire sidewall is suppressed, iron powder is difficult to adhere to the tire sidewall. Therefore, even after years of use, the tire 10 can suppress the decrease in power supply efficiency.

[0320] It should be noted that, relative to 100 parts by weight of rubber, the anti-aging agent is preferably contained in 0.7 to 7.8 parts by weight, and most preferably in 0.8 to 7.5 parts by weight. Furthermore, relative to 100 parts by weight of rubber, the wax is preferably contained in 0.2 to 4.8 parts by weight, and even more preferably in 0.3 to 4.5 parts by weight.

[0321] Figure 21 This is a radial sectional view showing an improved example of the tire according to this embodiment. In this embodiment, a different type of tire may also be used. Figure 21 The tire shown is 10B instead. Figure 20 The tire shown is 10A. (As shown) Figure 21 As shown, tire 10B is a run-flat tire with a run-flat liner 27 mainly provided on the outer sidewall portion B in the tire width direction of the inner liner 12. The run-flat liner 27 is formed at least throughout the sidewall portion B and the shoulder portion C between the inner liner 12 and the tire body 18. It should be noted that when the run-flat liner 27 is provided, the coil 40 can also be provided on the inner circumference of the inner liner 12. Furthermore, in Figure 21 In the example shown, the carcass 18 is composed of two carcass plies 19a and 19b. Carcass ply 19a terminates at the upper radial part of the tire in the zero-pressure liner 27, while carcass ply 19b terminates at the central radial part of the tire in the sidewall core 16.

[0322] for Figure 20 and Figure 21In either of the tires 10A and 10B shown, the receiving coil 40 can be disposed on the inner surface of the tire via a support layer (not shown) disposed between the receiving coil 40 and the inner surface of the tire (composed of the inner liner 12). The support layer is a plate-shaped member of a specified thickness, formed of an insulating material, such as rubber or synthetic resin. The outer side of the support layer in the tire width direction can also be bonded to the inner liner 12 by an adhesive. The receiving coil is disposed on the inner side of the support layer in the tire width direction. The receiving coil can be bonded to the support layer by an adhesive. In another example, the receiving coil 40 can also be covered by a covering layer. The covering layer can be formed of the same material as the support layer or a different material. In this case, the support layer, the receiving coil 40, and the covering layer are arranged sequentially from the outer side in the tire width direction to the inner side in the tire width direction, and are formed integrally on the inner surface of the tire. The receiving coil 40 is held between the support layer and the covering layer. Furthermore, in another example, the receiving coil 40 can also be embedded in the support layer. In this case, the support layer has a thickness sufficient to cover the receiving coil 40.

[0323] (Additional Implementation Method 18)

[0324] In basic embodiment 2, the thickness t of the outer rubber layer is preferably 2.5 to 20.0 mm (additional embodiment 18), more preferably 2.7 to 18.0 mm, and extremely preferably 2.9 to 16.0 mm. The outer rubber layer in the radial region WH of the tire includes rim protector 24, sidewall tread 26, and wing tip 28. Figure 20 As shown, the thickness t of the outer rubber layer refers to the length in the direction perpendicular to the outer surface of the tire body 18 in the tire width direction, i.e., the outer surface of the folded-back portion 18b in the tire width direction. For example... Figure 20 As shown, the thickness t of the outer rubber layer varies in the radial direction of the tire. That is, the thickness t of the outer rubber layer is preferably within the above-mentioned range at any location.

[0325] By keeping the thickness t of the outer rubber layer within the aforementioned range, tire 10A can maintain the performance of the outer rubber layer and prevent excessive content of anti-aging agents and waxes, thereby more reliably suppressing the precipitation of anti-aging agents and waxes.

[0326] If the thickness t of the outer rubber layer of tire 10A is too large, the overall content of anti-aging agents and waxes in the outer rubber layer will be excessive. On the other hand, if the thickness t of the outer rubber layer of tire 10A is too small, it is difficult to maintain the performance of the outer rubber layer.

[0327] (Additional Implementation Method 19)

[0328] Figure 22 This is a meridional cross-sectional view used to illustrate the deflection of the tire in the width direction of the tire according to this embodiment. In the case of Basic Embodiment 2 or Basic Embodiment 2 with Additional Embodiment 18, it is preferable to... Figure 22 As shown, in a tire 10A mounted on a specified rim and subjected to a normal internal pressure, the tire radial length SH (mm) from the toe 33 to the tread surface 34 of the tire 10A in an unloaded state, and the tire width deflection D before and after applying a load corresponding to 80% of the normal load to the tire 10A, satisfy the following formula (2) (Additional Embodiment 19).

[0329] 0.0278×SH-1.33≤D≤0.286×SH-13.7……(2)

[0330] Figure 22 The radial section shown by the dashed line represents a tire 10A in an unloaded state, mounted on a specified rim and with a standard internal pressure applied. The radial length of the tire (also known as the tire section height) from the unloaded toe 33 to the tread surface 34 at the contact patch center is denoted as SH (mm). Furthermore, the width length of the tire in the unloaded state is denoted as D1. Figure 21 The meridian profile shown by the solid line represents a tire 10A mounted on a specified rim and with the normal internal pressure, after a load corresponding to 80% of the normal load has been applied. The length in the tire width direction at the contact patch center after applying a load corresponding to 80% of the normal load is defined as D2.

[0331] The tire deflection D in the width direction before and after applying a load corresponding to 80% of the normal load is the difference (D2-D1) between the tire width length D1 in the unloaded state and the tire width length D2 after applying a load corresponding to 80% of the normal load.

[0332] Regarding tire 10A, preferably, in a radial cross-sectional view of the tire, at least 6% of the cross-sectional area of ​​the rubber disposed in the radial region WH of the tire has a JIS hardness of 65 or higher, more preferably at least 8%, and extremely preferably at least 10%. The rubber disposed in the radial region WH of the tire includes a sidewall core 16, a rim protector 24, (second filler 25), and a sidewall tread 26. The JIS hardness is the hardness measured by a type A durometer according to JIS-K6253 at a temperature of 23°C.

[0333] Tire 10A maintains tire performance during rolling by keeping the deflection D within the range expressed by the above formula (2), and suppresses deformation of the tire sidewall centered on the sidewall portion B. By suppressing deformation of the tire sidewall, tire 10A is able to suppress the exudation of anti-aging agents and waxes from the rubber on the tire sidewall.

[0334] When the deformation of the tire sidewall is too large, i.e., when the tire 10 is prone to deformation, the tire 10 will deform repeatedly, causing the anti-aging agent and wax to easily leach out from the rubber on the tire sidewall. In addition, when the deformation of the tire sidewall is too large, the current receiving coil located on the inner surface of the tire in the radial region WH of the tire is prone to detaching from the inner surface of the tire.

[0335] It should be noted that in the above formula (2), the deflection amount D is more preferably 0.0278×SH-1.31≤D, and extremely preferably 0.0278×SH-1.29≤D. Similarly, the deflection amount D is more preferably D≤0.286×SH-13.9, and extremely preferably D≤0.286×SH-14.1.

[0336] (Additional Implementation Method 20)

[0337] In the basic embodiment 2 or in which at least one of the additional embodiments 18 and 19 is added, it is preferred that the cross-sectional area S of the outer rubber layer is... o With 100% modulus M o The sum of the products, and the cross-sectional area S of the inner rubber layer disposed inside the tire width direction of the outer rubber layer and not exposed on the tire sidewall. i With 100% modulus M i The sum of their products satisfies the following equation (3) (Additional Implementation 20).

[0338] [Formula 4]

[0339]

[0340] The cross-sectional area is the cross-sectional area of ​​the rubber in the meridian section. The inner rubber layer consists of the sidewall core 16 and the second filler 25. The inner rubber layer does not include the liner 12 and the carcass 18. Figure 20 In a tire, the cross-sectional area S of the outer rubber layer ok The cross-sectional area S of the rim protector 24 is the radial region WH of the tire. o1 The cross-sectional area S of the sidewall tread 26 o2 and the cross-sectional area S of the wingtip 28 o3 The cross-sectional area S of the inner rubber layer ik The cross-sectional area S of the sidewall core 16 is the range of the radial region WH of the tire. i1 and the cross-sectional area S of the second filler 25 i2 .

[0341] 100% modulus is the tensile stress at 100% elongation. 100% modulus can be determined by the following steps: First, cut a JIS No. 3 dumbbell-shaped test piece from rubber test pieces obtained from various parts of the tire according to JIS K6251. Next, measure the 100% deformation stress according to JIS K6251. This 100% deformation stress is set as the measured value of the 100% modulus.

[0342] 100% modulus M of the outer rubber layer ok The measured value M of rim protector 24 o1 The measured value M of the sidewall tread 26 o2 And the measured value M at the wingtip 28 o3 The 100% modulus M of the inner rubber layer ik The measured value M of the tire sidewall core 16 i1 And the measured value M of the second filler 25 i2 .

[0343] The cross-sectional area S of the outer rubber layer in the above formula (3) o With 100% modulus M o The sum of these products is the load required for 100% deformation of the outer rubber layer (hereinafter referred to as the "outer rubber load"). Similarly, the cross-sectional area S of the inner rubber layer... i With 100% modulus M i The sum of these products is the load required for 100% deformation of the inner rubber layer (hereinafter referred to as the "inner rubber load"). In this specification, the value obtained by dividing the inner rubber load by the outer rubber load is called the load index.

[0344] By keeping the load index within the range of equation (3) above, the tire can suppress deformation of the tire sidewall, suppress the precipitation of anti-aging agents and waxes from the rubber on the tire sidewall, and ensure the cut resistance of the outer rubber layer. When the load index is less than the above range, the tire deformation increases excessively due to insufficient rigidity of the inner rubber layer, or the volume of the outer rubber layer increases excessively, thereby increasing the precipitation of anti-aging agents and waxes. On the other hand, when the load index is greater than the above range, the thickness of the outer rubber layer is too small, thereby reducing the cut resistance of the tire sidewall.

[0345] By ensuring that the load index satisfies equation (3), tire performance during rolling is maintained, and deformation of the tire sidewall centered on sidewall portion B is suppressed. Therefore, the function of tire 10 is maintained, and the amount of deformation of tire 10 is suppressed, thereby suppressing the amount of anti-aging agent and wax exudation.

[0346] It should be noted that the above-mentioned load index value is more preferably set to 0.35 or higher and 6.5 or lower, and extremely preferably set to 0.4 or higher and 6.0 or lower. Figure 21In the case of the tire 10A shown, which includes a zero-pressure liner 27, the inner rubber layer consists of a sidewall core 16, a second filler 25, and a zero-pressure liner 27.

[0347] (Additional Implementation Method 21)

[0348] In the basic embodiment 2 or in which at least one of the additional embodiments 18 to 20 is added, it is preferred that the height of the unevenness of the outer rubber surface is 2.0 mm or less (additional embodiment 21).

[0349] Tire 10A may have, for example, embossing, markings, serrations, and decorative patterns as unevenness on the outer rubber surface, i.e., the tire sidewall. The height of the unevenness formed on the outer rubber surface (tire sidewall) of tire 10A is 2.0 mm or less. Unevenness refers to the shape of a surface with peaks and valleys. The height of the unevenness refers to the length in the thickness direction of the outer rubber layer between the position where the peak height is greatest and the position where the valley depth is greatest. By keeping the height of the aforementioned unevenness of tire 10A to 2.0 mm or less, iron powder is less likely to accumulate in the uneven portions. Therefore, tire 10A suppresses iron powder adhesion to the uneven portions of the tire sidewall. It should be noted that the lateral grooves (not shown) formed on the tire shoulder C are not included in the aforementioned unevenness. This is because, since the tire shoulder C is near the belt 20, even if iron powder accumulates in the lateral grooves formed on the tire shoulder C, the impact on power supply efficiency is relatively small.

[0350] (Additional Implementation Method 22)

[0351] In the basic embodiment 2 or in which at least one of the additional embodiments 18 to 21 is added, it is preferable that the receiving coil 40 generates electricity by receiving a magnetic field transmitted from a supply coil disposed outside the tire in the tire width direction, in a tire radial cross-sectional view ( Figure 20 In the following embodiment, the radial region R1 of the power receiving coil 40, whose radial length is defined by the length between the two ends of the power receiving coil 40 in the radial direction of the tire, and the near-power receiving region R2, which is adjacent to the radial sides of the tire relative to the radial region R1 and whose radial length is defined by 15% of the radial length of the tire radial region WH, contains an anti-aging agent in the amount of 0.5 to 7.5 parts by weight relative to 100 parts by weight of rubber, and contains wax in the amount of 0.1 to 4.5 parts by weight relative to 100 parts by weight of rubber, and the height of the unevenness of the surface of the outer rubber layer is 1.5 mm or less (Additional Embodiment 22).

[0352] Tire 10A maintains the performance of the outer rubber layer by keeping the content of anti-aging agents and waxes in the charged region AR within the aforementioned range, and more reliably suppresses the precipitation of anti-aging agents and waxes. Furthermore, by keeping the height of the unevenness of the outer rubber surface within the aforementioned range, tire 10A prevents iron powder from accumulating in the uneven areas, thus more reliably suppressing iron powder adhesion to the uneven areas of the tire sidewall. Therefore, tire 10A more reliably suppresses iron powder adhesion to the tire sidewall of the charged region AR.

[0353] The outer rubber layer of the aforementioned power-receiving area AR varies depending on the location of the power-receiving coil 40. Figure 20 In the tire 10A shown, the outer rubber layer of the receiving area AR is the sidewall tread 26. The receiving coil 40 is positioned at a point... Figure 20 When the position shown is further outward from the radial direction of the tire, the outer rubber layer of the receiving area AR includes the sidewall tread 26 and the wing tip 28. Furthermore, when the receiving coil 40 is positioned further outward than... Figure 20 When the position shown is closer to the radial inner side of the tire, the outer rubber layer of the receiving area AR includes the sidewall tread 26 and the rim protector 24. Furthermore, when the receiving coil 40 is positioned radially closer to the tire than... Figure 20 In the case of a wider range shown, the outer rubber layer of the electrically charged area AR includes rim protector 24, sidewall tread 26, and wing tip 28.

[0354] 3. Third Implementation Method

[0355] Hereinafter, with reference to the accompanying drawings, a third embodiment of the tire of the present invention (basic embodiment 3 and additional embodiments 23-27 shown below) will be described in detail. It should be noted that the third embodiment does not limit the present invention. Furthermore, the constituent elements of the third embodiment include elements that can be easily replaced by those skilled in the art, or substantially the same elements. Moreover, the third embodiment can be arbitrarily combined within the scope that is obvious to those skilled in the art. The third embodiment can be arbitrarily combined with the first embodiment and the second embodiment described above.

[0356] [Basic Implementation Method 3]

[0357] Figure 23 This is a meridional sectional view of one side of the tire in the width direction, with the tire equatorial plane (not shown) as a reference. It should be noted that this figure shows the tire portion on the side opposite to the contact patch when it is assembled to the rim and subjected to normal internal pressure and 80% of the normal load (hereinafter, the same applies to the invention of the tire).

[0358] like Figure 23 As shown, the tire 10C of this embodiment has a bead portion A, a sidewall portion B, a shoulder portion C, and a tread portion D extending radially from the inner side of the tire to the outer side. An inner liner 12 exposed to the inner surface of the tire is provided in the area from the bead portion A to the tread portion D. A tire body 18 is provided on the side of the inner liner 12 opposite to the inner surface of the tire cavity. The tire body 18 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 sidewall core 16. On the radial outer side of the tire body 18 at 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 radially outward.

[0359] Furthermore, a rim protector 24 is provided further outward in the tire width direction of the folded-back portion 18b of the tire carcass 18, which is located on the outer side of the bead core 14 and the sidewall core 16. A sidewall tread 26, a wing tip 28, and a crown 30 are sequentially provided on the radially outer side of the rim protector 24. It should be noted that the tire in this embodiment is not limited to... Figure 23 The examples shown also include, for instance, run-flat tires in which a zero-pressure liner is provided primarily on the outer sidewall portion B in the tire width direction of the inner liner 12.

[0360] In the tire 10C configured as shown above, the inner liner 12 is a layer used to block gas from contacting the inner surface of the tire. The inner liner 12 may consist of a single inner liner layer or multiple inner liner layers stacked radially along the tire equator. The inner liner 12 includes at least one layer made of low-permeability rubber or a layer made of resin, and may include an adhesive layer as another layer at least in the contact portion with the tire carcass 18.

[0361] The bead core 14 is, for example, an annular reinforcement formed by bundling cords, and can be configured as a structure in which rubber is used to cover the area around multiple bead wires made of steel cords or organic fiber cords. The sidewall core 16 is a component used to improve the rigidity of the bead portion A, and can be configured as follows: Figure 23 The approximate triangular shape shown has a tire width dimension at the inner radial end of the tire and a tire width dimension at the outer radial end of the tire bead core 14 that are approximately equal, and the tire width dimension gradually decreases towards the outer radial direction of the tire.

[0362] The carcass 18 is a component forming the skeleton of the tire 10C, and is composed of at least one carcass layer (carcass ply), each carcass layer having a structure in which multiple carcass cords are covered with rubber. Typically, steel cords or organic fiber cords are used as carcass cords. However, in the tire 10C of this embodiment, as described later, in order to prevent the magnetic field generated in the sidewall portion B, which penetrates the inner cavity surface of the inner liner 12 substantially perpendicularly, from being obstructed by the metal component, a non-magnetic material is preferably used as the carcass cord. For example, organic fibers such as rayon, polyester, polyamide, and aramid can be used as non-magnetic materials.

[0363] The belt 20 is a reinforcing layer disposed on the radially outer side of the tire carcass 18. It is a component that secures the tire carcass 18, increases the rigidity of the tread portion, thereby improving driving stability, and reduces rolling resistance by decreasing strain deformation. The belt 20 can be composed of multiple belt layers stacked radially along the tire tread portion D. Figure 23 The example shown consists of two bundle layers 20a and 20b. Each bundle layer 20a and 20b is composed of multiple bundle cords covered with rubber. Typically, steel cords or organic fiber cords are used as bundle cords. As bundle cords, it is natural to use magnetic materials such as steel cords, but non-magnetic materials (including paramagnetic and diamagnetic materials) can also be used.

[0364] The belt cover 22 is a component that enhances the securing effect of the belt 20 to the tire carcass 18, particularly for preventing deformation of the tread portion D due to centrifugal forces generated during high-speed vehicle operation. The belt cover 22 can be composed of multiple belt cover layers stacked radially outward from the tire on the radial side of the belt 20. Figure 23 The example shown consists of three belt cover layers 22a, 22b, and 22c. Each belt cover layer 22a, 22b, and 22c has a structure in which multiple cords are rubber-coated. Typically, steel cords or organic fiber cords are used as the cords used in the belt cover layers. As for the cords, it is natural to use magnetic materials such as steel cords, but non-magnetic materials (including paramagnetic and diamagnetic materials) can also be used.

[0365] A rim protector 24 is disposed in the area contacting the rim flange of a wheel (not shown), and a sidewall tread 26 is configured to connect the rim protector 24 to the tread portion D. In a radial sectional view of the tire, winglets 28 are respectively disposed at the boundaries of the tread portion D and the sidewall tread 26 on the left and right sides of the tire, and a crown 30 is formed on the surface of the tread portion D in a manner that covers the entire area of ​​the tire contact patch. A run-flat liner (not shown) is formed on the outer periphery of the inner liner 12, covering at least the sidewall portion B (and possibly the bead portion A and / or the shoulder portion C). It should be noted that the rim protector 24, sidewall tread 26, winglets 28, crown 30, and run-flat liner can all utilize conventionally used rubber components according to their respective required characteristics.

[0366] Assuming the presence of the constituent elements 12 to 30 of the tire 10C shown above (including, depending on the case, a zero-pressure liner), the tire 10C of this embodiment receives a high-voltage coil 40 on its inner cavity surface. Figure 23 The receiving coil 40 receives alternating current from a power supply coil (not shown) located outside the tire 10C. The receiving coil 40 can be disposed in contact with the inner liner 12 or embedded within the inner liner 12. Furthermore, the receiving coil 40 can also be fixed to the inner liner 12 via a fixing member other than rubber (e.g., made of a non-magnetic material, particularly silicone rubber or other rubbers with relatively high thermal conductivity). It should be noted that, in the case of a zero-pressure liner, the receiving coil 40 can also be disposed on the inner circumference of the inner liner 12.

[0367] In the power supply of the tire 10C using this embodiment, for example, a direct current obtained from an on-board battery (not shown) is temporarily converted into an alternating current by an AC power supply device, and this alternating current is applied to a power supply coil (e.g., mounted on the tire side surface of a steering knuckle or wheel hub, which is a component of the vehicle's steering axle, or any component constituting the strut structure), thereby generating an alternating magnetic field around the power supply coil. This alternating magnetic field links with a receiving coil 40, thereby generating an induced electromotive force in the receiving coil 40 to supply power.

[0368] When such power supply is achieved, in the tire 10C of this embodiment, in the radial region CW between the two feet of the perpendicular lines drawn from the two ends of the tire radial direction of the power receiving coil 40 to the inner liner 12 formed on the inner periphery side of the tire body 18, the thermal conductivity λ1 of the inner liner 12 is 0.10 W / m・K or more.

[0369] In this embodiment, thermal conductivity is determined by the heat flow meter method as specified in JISA 1412-2 and ISO 8301, or the laser flash method as specified in JIS R 1611, or other methods as specified in other standards equivalent to these methods.

[0370] (Functions, etc.)

[0371] As mentioned above, conventionally, the receiving coil is usually mounted on a metal rim, thus the alternating magnetic field is affected by the rim, and there is a tendency for the acceptable power of the receiving coil to decrease (Patent Document 1, ...). Figure 1 On the other hand, when the receiving coil is partially off the ground from the metal rim, although the power supply efficiency is improved, it is difficult to dissipate the heat generated by the receiving coil.

[0372] Therefore, the inventors have conducted in-depth research on setting the location of the receiving coil as a tire component, which is a tire component other than metal parts, and whose surface area (i.e., heat dissipation area) is as large as possible. As a result, the inventors, focusing on setting the receiving coil in the inner liner formed on the inner periphery of the tire body, have reached the following insight: by appropriately adjusting the thermal conductivity of the inner liner in at least a specified area, even if a temperature rise occurs near the location of the receiving coil during power reception, heat will not locally accumulate in the rim-assembled tire, and the fixing state of the receiving coil remains good, thereby achieving excellent power supply efficiency. It should be noted that the specific basis for selecting the specified area of ​​the inner liner with a specific thermal conductivity, and the selection of the range of that thermal conductivity, is as follows.

[0373] As mentioned above, regarding the location of the power supply coil, an example that can be cited is the steering knuckle (not shown), which is a component of the steering shaft of a vehicle. This steering knuckle is typically located in... Figure 23 The middle part is located on the outer side of the tire width direction of sidewall B. Figure 23 (Right side of the middle). Therefore, the magnetic field generated between the power supply coil and the power receiving coil 40 is generated in such a way that the magnetic field lines in the side wall portion B penetrate the inner cavity surface of the liner 12 approximately perpendicularly.

[0374] Furthermore, while the receiving coil 40 generates heat during power supply, the heat generated by the tire 10C, in addition to that generated by the receiving coil 40, also includes heat generated by the rubber components that roll with the tire, and heat generated by friction between the road surface and the tire tread. In such a harsh environment with multiple causes of heat generation, it is important to efficiently dissipate the heat generated by the receiving coil 40.

[0375] Therefore, by from Figure 23 In the radial region CW of the tire between the two feet of the perpendicular lines drawn from the two radial ends of the receiving coil 40 to the inner liner 12, the thermal conductivity of the inner liner 12 is set to 0.10 W / m·K or higher. This promotes heat diffusion within the inner liner 12, which is close to the heat source, i.e., the receiving coil 40, thereby suppressing the temperature rise of the receiving coil 40. As a result, heat is prevented from accumulating locally within the tire 10C. Consequently, the fixed state of the receiving coil 40 and the inner liner 12 can be well maintained, and deformation of the receiving coil 40 can be suppressed, thereby achieving excellent power supply efficiency.

[0376] Here, the thermal conductivity is preferably set to 0.11 W / m·K or higher, and extremely preferably 0.12 W / m·K or higher.

[0377] (Additional Implementation Method 23)

[0378] In basic implementation 1, it is preferable to view the tire radial section ( Figure 23 In this embodiment, the receiving coil 40 is disposed in the radial region WH of the tire, from the outermost radial position P1 of the tire bead core 14 to the innermost radial position P2 of the tire belt 20 (Additional Embodiment 23).

[0379] In the aforementioned Patent Document 1, a wireless power receiving system is known that supplies power between a power transmission coil buried near the road surface and a power receiving coil installed on the centerline of the tire width direction of a wheel (Patent Document 1, Figure 1 In this wireless power receiving system, the magnetic field from the transmitting coil to the receiving coil can sometimes be affected by the belt bundle. For example, in this wireless power receiving system, if the belt bundle uses a metallic (magnetic material only) belt cord, a portion of the magnetic field that should have reached the receiving coil from the transmitting coil is blocked by the magnetic material (belt cord) contained in the belt bundle, which may prevent the achievement of excellent power supply efficiency.

[0380] Therefore, the inventors have repeatedly conducted in-depth research on the following tire 10C: even when Figure 23 When the belt 20 shown uses a metal belt cord, a portion of the magnetic field that should reach the receiving coil 40 from the power supply coil is not blocked by the tire 10C, which contains magnetic material between the two coils, thereby achieving excellent power supply efficiency.

[0381] Specifically, the inventors have conducted in-depth research on the optimal position of the receiving coil 40, which is disposed on the inner surface of the tire 10C, relative to the power supply coil (not shown) disposed on the outside of the tire 10C.

[0382] First, the inventors et al. Figure 23 By focusing on multiple line segments from each point (starting point) on the inner surface of the tire (the same applies in the case of a zero-pressure liner) to each point (end point) on the outer surface of the tire with the shortest distance, the following insights were obtained: by extracting a region consisting of multiple line segments that do not contain the belt 20 from these line segments, and setting the receiving coil 40 in a manner that does not deviate from the inner surface of the tire contained in the region, most of the magnetic field generated between the two coils will not be blocked by the belt 20, which may contain magnetic material.

[0383] Next, considering that the above-mentioned insights are for defining the radially outer end of the tire in the area where the receiving coil 40 is installed, the inventors further investigated the radially inner end of the tire that defines this area. As a result, the inventors, focusing on the bead core 14 which may be made of a metal component, also concluded that by extracting an area composed of multiple line segments that do not include the bead core 14, and installing the receiving coil 40 in a manner that does not detach from the inner surface of the tire cavity contained in that area, most of the magnetic field generated between the two coils will not be blocked by the bead core 14, which may contain magnetic material.

[0384] Based on the above insights, in the tire 10C of this embodiment, the receiving coil 40 is disposed in the radial region WH of the tire, from the outermost radial position of the bead core 14 to the innermost radial position of the belt 20. Therefore, according to the tire 10C of this embodiment, since there is no excessive arrangement of tire 10C components that may contain magnetic materials between the supply coil and the receiving coil 40, the power supply efficiency can be improved.

[0385] (Additional Implementation Method 24)

[0386] In the basic embodiment 3 or the basic embodiment 3 with the addition of additional embodiment 22, it is preferable that the tire radial profile is cut at a position other than the end of the receiving coil 40 (e.g., Figure 23 In the above, the total cross-sectional area S (m²) of the conductors of the receiving coil 40 is... 2 The relationship between the resistance value r (Ω) of the receiving coil 40 at the frequency of the aforementioned alternating current and the thermal conductivity λ1 (W / m・K) of the inner lining 12 satisfies

[0387] 1×10 5 ≤r / (λ1×S)≤8×10 7

[0388] (Additional Implementation Method 24).

[0389] Here, the receiving coil 40 is composed of conductive wires physically connected to the connected circuit (resonant circuit and / or rectifier circuit, etc.), excluding any independent relay circuits in the presence of such circuits. Furthermore, the resistance value r (Ω) of the receiving coil 40 is obtained by measuring the resistance when a specific frequency of alternating current is applied to both ends of the receiving coil 40 using an impedance analyzer or network analyzer. Here, the specific frequency refers to the frequency of the alternating current generated by the AC power source in the power supply system; in other words, it refers to the frequency of the power supplied to the transmitting coil, or the frequency of the alternating magnetic field generated during the transmission gap—that is, the frequency that enables wireless power supply.

[0390] Figure 24 It means Figure 23 This is a schematic diagram showing the winding configuration of the receiving coil 40 in the tire circumferential direction. If... Figure 24 The tire meridian section shown along line A-A' indicates that the shape of the receiving coil 40 is as follows: Figure 23 As shown. In contrast, in Figure 24 In most of the region X enclosed by the dashed line (especially the central region in the vertical direction of the paper), in the case of a tire meridian section cut along the tire width direction, it is similar to... Figure 23 Compared to the previous case, the receiving coil 40 is longer in the tire width direction. Therefore, in this embodiment, in Figure 24 The tire meridian profile cut along the tire width direction within the area X enclosed by the dashed line is excluded.

[0391] Here, in this embodiment, [r / (λ1×S)] is an index representing the degree of temperature rise when the region containing the receiving coil 40 and its adjacent liner 12 heats up. That is, if the total cross-sectional area S (m²) of each unit conductor of the receiving coil 40 is [r / (λ1×S)], then [r / (λ1×S)] is considered as [r / (λ1×S)]. 2 If the resistance (r / S) of the receiving coil 40 is high, more heat will be generated, resulting in a higher temperature rise. If the thermal conductivity λ1 (W / m・K) of the lining 12 is low, heat dissipation cannot be promoted, resulting in a higher temperature rise.

[0392] By setting the upper limit of [r / (λ1×S)] to 8×10 7 The following measures can suppress the temperature rise in the area containing the coil 40 and the inner liner 12 when heating occurs, thereby further improving the durability of the tire 10C by maintaining the coil 40 and the inner liner 12 in a better fixed state.

[0393] Conversely, if the total cross-sectional area S (m²) of the conductor of the current-receiving coil 40 is excessively increased... 2 As the weight of the receiving coil 40 increases, the rolling resistance increases and the combustion efficiency decreases. Therefore, by increasing the total cross-sectional area S (m²) of the conductors of the receiving coil 40... 2 However, since the value is not large, the lower limit of [r / (λ1×S)] is set to 1×10. 5 The above enables efficient power supply with good combustion efficiency, thereby achieving excellent transmission efficiency.

[0394] It should be noted that the upper limit of [r / (λ1×S)] is preferably set to 6×10. 7 Hereinafter, the optimal setting is 4×10 7 Furthermore, on the other hand, its lower limit is preferably set to 2×10. 5 The optimal setting is 4×10. 5 above.

[0395] (Additional Implementation Method 25)

[0396] In the basic embodiment 3 or the basic embodiment 3 with at least one of the additional embodiments 23 and 24, it is preferable that the thermal conductivity λ2 of the rubber layer other than the inner liner 12 in the above-mentioned tire radial region WH (the tire radial region from the outermost position of the tire bead core 14 to the innermost position of the tire radial region of the belt 20) is 0.13 W / m・k or more (additional embodiment 25).

[0397] Here, the rubber layers other than the inner liner 12 include rim protector 24, sidewall tread 26, sidewall core 16, wing tip 28, and zero-pressure liner (not shown). It should be noted that this rubber layer also includes a second filler (not shown) located on the outer side of the folded portion 18b of the tire carcass in the tire width direction and on the inner side of the rim protector 24 and the sidewall tread 26 in the tire width direction.

[0398] Through Figure 23 In the radial region WH of the tire, centered on the sidewall portion B and extending to the nearby bead portion A and shoulder portion C, setting the thermal conductivity λ2 of the aforementioned rubber layer to 0.13 W / m·K or higher further promotes heat diffusion in this region, thereby further suppressing the temperature rise of the current-receiving coil 40. As a result, localized heat accumulation in the tire 10C can be further avoided, thereby better maintaining the fixed state of the current-receiving coil 40 and the inner liner 12 and further improving the durability of the tire 10C.

[0399] (Additional Implementation Method 26)

[0400] Figure 25 This indicates that the fixed component 41 is relative to... Figure 23 The schematic diagram shows a specific example of the setting ratio of the receiving coil 40, namely [(∑θ2) / θ1]. (A) shows an example of setting multiple fixed members 41a at certain intervals, and (B) shows an example of setting one fixed member 41b.

[0401] In the basic embodiment 3 or in which at least one of the additional embodiments 23 to 25 is added, it is preferable to provide a fixing member 41 (41a, 41b) for fixing the receiving coil 40 to the inner surface of the tire cavity.

[0402] With the tire center as the reference, the ratio of the sum of the tire circumferential setting angles θ2 of the fixing member ∑θ2 to the tire circumferential setting angle θ1 of the receiving coil 40 [(∑θ2) / θ1] is related to the thermal conductivity λ3 (W / m・K) of the fixing member.

[0403] 0.14×[(∑θ2) / θ1]+0.13≤λ3≤0.38×[(∑θ2) / θ1]+0.42

[0404] (Additional Implementation Method 25).

[0405] exist Figure 25 In either example (A) or (B), the tire circumferential configuration angle θ1 of the receiving coil 40 is 360°, therefore in Figure 25 In the examples shown in (A) and (B), the above ratio can be expressed as [(Σθ2) / 360°].

[0406] By setting the thermal conductivity λ3 of the fixing member 41 within a range above the lower limit of the above formula, the temperature rise of the receiving coil 40, which is heated by the power supply, can be suppressed, thereby further improving the durability of the tire 10C by maintaining the fixed state of the receiving coil 40 and the inner liner 12.

[0407] In contrast, by setting the thermal conductivity λ3 of the fixing member 41 to a range below the upper limit of the above formula, the fixing member 41 can follow the inner liner 12 well when the tire deforms during tire rolling, thereby further improving the durability of the tire 10C by maintaining the fixed state of the coil 40 and the inner liner 12.

[0408] It should be noted that in this embodiment, when the receiving coil 40 is embedded in the inner liner 12, the inner liner 12 is considered as a fixing member 41.

[0409] Furthermore, regarding the thermal conductivity λ1 of the lining 12 and the thermal conductivity λ3 of the fixing member 41, from the viewpoint of heat dissipation, it is preferable that λ3 is greater than λ1. The relationship between thermal conductivity λ1 and λ2 is more preferably λ3>1.1×λ1, and extremely preferably λ3>1.2×λ1.

[0410] Furthermore, such as Figure 25 As shown in example (A), when multiple fixing members 41a are arranged at intervals, it is preferable to set the tire circumferential angle α between adjacent fixing members to 35° or less, with the tire center as the reference. With this configuration, frictional heat that may be generated between the wire constituting the current-receiving coil 40 and its adjacent rubber components in areas where fixing members 41a are not located during tire rolling (vehicle travel) can be reduced, thereby suppressing overall tire heating. As a result, the fixed state of the current-receiving coil 40 and the inner liner 12 can be maintained even better, further improving the durability of the tire 10C.

[0411] It should be noted that, with the tire center as the reference, the tire circumferential angle between adjacent fixed components is more preferably 33° or less, and extremely preferably 30° or less.

[0412] (Additional Implementation Method 27)

[0413] Figure 26 This is a cross-sectional view showing the wire 42 constituting the current-receiving coil 40. As shown in the figure, the wire 42 includes a wire 42a and a covering layer 42b covering the wire 42a. The wire 42a is made of a conductor, and in the case of using it in a high-frequency AC circuit as in this embodiment, a conductor with a low resistance value is particularly suitable. Furthermore, for the wire 42a, if the condition of using it as a coil to receive a magnetic field is further added, copper, as a non-magnetic metal with low magnetic permeability, is most suitable.

[0414] The covering layer 42b is made of an insulating material, and in particular, if flexibility is required to balance processability, it is made of a resin material. Especially in this embodiment, since it is desirable for the covering layer 42b to have high thermal conductivity, it is preferably made of resin materials such as polyurethane, polyester, polyvinyl formal, polyethylene, nylon, polyvinyl chloride, polyamide-imide, polyesterimide, and polyimide.

[0415] In the basic embodiment 3 or the basic embodiment 3 with at least one of the additional embodiments 23 to 26, it is preferred that the conductor 42 constituting the receiving coil 40 includes a wire 42a and a covering layer 42b covering the wire 42a, the thermal conductivity λ4 (W / m·K) of the covering layer 42b is greater than the thermal conductivity λ1 (W / m·K) of the inner liner 12, and the thickness of the covering layer 42b is 10 to 100 μm (additional embodiment 27).

[0416] By making the thermal conductivity λ4 (W / m·K) of the covering layer 42b greater than the thermal conductivity λ1 (W / m·K) of the inner liner 12, and / or setting the thickness of the covering layer 42b to 100 μm or less, the heat generated by the wire 42a can be more efficiently diffused to the inner liner 12 via the covering layer 42b. This further improves the durability of the tire 10C by better maintaining the fixed state between the receiving coil 40 and the inner liner 12. It should be noted that, from the viewpoint of further promoting the aforementioned heat diffusion, the thermal conductivity λ4 of the covering layer 42b is more preferably 0.15 (W / m·K) or more, more preferably 0.16 (W / m·K) or more, and extremely preferably 0.17 (W / m·K) or more. Similarly, from the viewpoint of further promoting the aforementioned heat diffusion, the thickness of the covering layer 42b is more preferably 90 μm or less, and extremely preferably 80 μm or less.

[0417] In contrast, by setting the thickness of the coating layer 42b to 10 μm or more, the formability of the wire 42 can be ensured, as well as the durability of the wire 42 itself, thereby improving the durability of the tire 10C. Setting the thickness of the coating layer 42b to 12 μm or more makes this effect even better, and setting it to 15 μm or more makes this effect extremely good.

[0418] Example

[0419] 1. First Embodiment

[0420] Hereinafter, a comparison of the effects of the first inventions (hereinafter referred to as "Examples 1-1 to 1-13") as defined in claims 1 to 13 of this application corresponding to the first embodiment will be described. It should be noted that, regarding the comparison between Examples 1-1 to 1-13 and the prior art (examples described in Patent Document 1), as mentioned above, the differences in the effects of the present application are more obvious in structure, and therefore will not be specifically described together.

[0421] Set the tire size to 245 / 40R19 (as specified by JATMA) and manufacture... Figure 13 The power supply efficiency from the power supply coil 52 to the power receiving coil 40 of the wireless power supply system 50 shown (Examples 1-1 to 1-13) was investigated. It should be noted that the conditions of the tires 10 included in each of the wireless power supply systems 50 of Examples 1-1 to 1-13 are shown in Tables 1-1 and 1-2 below.

[0422] [Table 1-1]

[0423]

[0424] [Table 1-2]

[0425]

[0426] For the wireless power supply systems of Invention Examples 1-1 to 1-13 constructed in this way, the ratio (power transmission efficiency) of the power 2 received by the receiving coil 40 (and the resonant circuit of the capacitor) to the power 1 transmitted from the transmitting coil 52 is measured, and these ratios are expressed using the exponent when Invention Example 1 is set to 100. It should be noted that the above-mentioned ratio of power 1 to 2 is measured using a vector network analyzer. The results are recorded in Tables 1-1 and 1-2. It should be noted that in this specification, a power transmission efficiency of 95 or higher is considered good.

[0427] As can be seen from Tables 1-1 and 1-2, the wireless power supply systems within the technical scope of this invention all exhibit excellent electromagnetic wave ratios after transmission, thereby achieving excellent power supply efficiency.

[0428] 2. Second Embodiment

[0429] Hereinafter, a comparison of the effects of the second inventions (hereinafter referred to as "Examples 2-1 to 2-9") as defined in the claims of this application corresponding to the second embodiments will be described. It should be noted that, regarding the comparison between Examples 2-1 to 2-9 and the prior art (examples described in Patent Document 1), as mentioned above, the differences in the effects of the present application are more obvious in structure, and therefore will not be specifically described together.

[0430] Set the tire size to 245 / 40R19 (as specified by JATMA) and manufacture... Figure 20 The tires shown are as described. It should be noted that the conditions for tires 10 in Examples 2-1 to 2-9 are shown in Table 2 below.

[0431]

[0432] It should be noted that in Table 2, the anti-aging agent, wax, thickness of outer rubber, deflection D, value calculated by formula (3) (load index), and height of unevenness are based on the definitions recorded in this specification.

[0433] For the wireless power supply system using the tires of Invention Examples 2-1 to 2-9, the ratio (power transmission efficiency) of the power 2 received by the receiving coil (and the resonant circuit of the capacitor) to the power 1 transmitted from the transmitting coil 52 was measured, and these ratios were expressed using the exponent when Invention Example 1 was set to 100. It should be noted that the ratio of power 1 to 2 was measured using a vector network analyzer. The results are recorded in Table 2. All tires were mounted on standard rims, an air pressure of 230 kPa was applied, and the tires were installed on the front wheels of a passenger car (FR sedan) weighing approximately 1800 kg. After driving 2000 km, the amount of precipitation and the presence of cracks were evaluated.

[0434] In Table 2, in the "Extraction Amount" column, based on the extraction amount of the anti-aging agent and wax in Invention Example 2-1, "A" indicates a case where the extraction amount is equal to or less than that in Invention Example 2-1, and "B" indicates a case where the extraction amount is greater than that in Invention Example 2-1. Furthermore, in the "Presence or Absence of Cracks" column, "A" indicates a case without crack damage, and "B" indicates a case with damage.

[0435] As shown in Table 2, the wireless power supply systems within the technical scope of this invention all exhibit excellent power transmission efficiency, thereby achieving excellent power supply efficiency.

[0436] 3. Third embodiment

[0437] Hereinafter, a comparison of the effects of the third inventions (hereinafter referred to as "Invention Examples 3-1 to 3-6") as defined in the claims of this application corresponding to the third embodiment will be described. It should be noted that, regarding the comparison between Invention Examples 3-1 to 3-6 and the prior art (the examples described in Patent Document 1), as mentioned above, the differences in the effects of the present application are more obvious in terms of their composition, and therefore will not be specifically described in the same way.

[0438] Set the tire size to 245 / 40R19 (as specified by JATMA) and manufacture... Figure 13 The power supply efficiency from the power supply coil 52 to the power receiving coil 40 of the wireless power supply system 50 shown (Examples 1-6) was investigated. It should be noted that the conditions of the tires included in each of the wireless power supply systems 50 of Examples 3-1 to 3-6 are shown in Table 3 below.

[0439]

[0440] ※0.14×[(Σθ2) / θ1]+0.13≤λ3≤0.38×[(Σθ2) / θ1]+0.42

[0441] It should be noted that in Table 3, thermal conductivity λ1~λ4, r, S, θ1 and θ2 are based on the definitions described in this specification.

[0442] For the wireless power supply systems of Invention Examples 3-1 to 3-6 constructed in this way, the ratio (power transmission efficiency) of the power 2 received by the receiving coil (and the resonant circuit of the capacitor) to the power 1 transmitted from the transmitting coil 52 is measured, and these ratios are expressed by the exponent when Invention Example 3-1 is set to 100. It should be noted that the above-mentioned ratio of power 1 to 2 is measured using a vector network analyzer. The results are also recorded in Table 3. It should be noted that in this specification, a power transmission efficiency of 95 or higher is considered good.

[0443] As shown in Table 3, the wireless power supply systems within the technical scope of this invention all exhibit excellent power transmission efficiency, thereby achieving excellent power supply efficiency.

[0444] Explanation of reference numerals in the attached figures

[0445] 10, 10A, 10B, 10C: Tires

[0446] 12: Lining

[0447] 14: Tire bead core

[0448] 16: Tire sidewall core

[0449] 18: Fetus

[0450] 19: Steel Reinforcement Component (SRF)

[0451] 20: Belt

[0452] 22: Belt cover

[0453] 24: Wheel rim protector

[0454] 25: Second filler

[0455] 26: Sidewall tread

[0456] 27: Zero-pressure liner

[0457] 28: Wing tip

[0458] 29: Second fetus

[0459] 30: tire crown

[0460] 31: Bead reinforcement layer

[0461] 32: Zero-pressure liner

[0462] 33: Fetal toe

[0463] 34: Tread

[0464] 40: Receiving coil

[0465] 40a: Elements of the receiving coil

[0466] 41: Fixed components

[0467] 42: Wire

[0468] 43: Conductive wire

[0469] 44: Support layer

[0470] 45: Power Line

[0471] 47: Electronic devices

[0472] 50: Wireless Power Supply System

[0473] 52: Transmission coil

[0474] 54: Wheel Cover

[0475] 60: Damper housing

[0476] 70: Steering knuckle

[0477] 72: Upper arm

[0478] A: Bead section

[0479] AR: Electric Receiving Area

[0480] B: Side wall portion

[0481] C: Tire shoulder

[0482] CP: Tire equatorial plane

[0483] CW: Tire radial zone

[0484] D: Fetal face

[0485] Dp: Power supply direction

[0486] G: Transmission gap

[0487] O: Tire Center

[0488] R1: Radial region of the receiving coil

[0489] R2: Area near power reception

[0490] WH: Tire radial zone

[0491] α: Tire circumferential angle

[0492] θ1: Tire circumferential configuration angle

[0493] θ2: Tire circumferential setting angle

Claims

1. A tire having a bead core, a sidewall core disposed radially outward of the bead core, a carcass folded back around the bead core, and a belt disposed radially outward of the carcass, wherein a receiving coil is disposed within the tire cavity, the receiving coil receiving electricity supplied from outside the tire via an alternating magnetic field. The tire is characterized in that, in a radial cross-sectional view of the tire, the receiving coil is disposed in the radial region of the tire extending from the outermost radial position of the bead core to the innermost radial position of the belt. The relative permittivity of the components disposed in the radial region of the tire, excluding the tread portion, is 3.5 or higher and 250 or lower.

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

3. The tire according to claim 1 or 2, wherein the relative permittivity of the rubber material constituting the sidewall tread is in the range of 3.5 to 40, and the relative permittivity of the rubber material constituting the rim protector and the sidewall core is in the range of 70 to 235.

4. The tire according to claim 1 or 2, wherein, The receiving coil generates electricity by receiving a magnetic field transmitted from a transmitting coil located outside the tire in the tire width direction. In a radial cross-sectional view of the tire, a sidewall tread with a relative permittivity between 3.5 and 37 is provided in the radial region of the coil, defined by the length between the two radial ends of the coil, and in the vicinity of the coil, which is adjacent to both radial sides of the coil and defined by a radial length of 15% of the radial length of the coil. No rim protector or sidewall core is provided. The relative permittivity of the rim protector and sidewall core disposed on the radial inner side of the tire in the radial region of the receiving coil and the region near the receiving coil is in the range of 70 to 250.

5. The tire according to claim 1 or 2, wherein, The receiving coil generates electricity by receiving a magnetic field transmitted from a transmitting coil located outside the tire in the tire width direction. In a radial cross-sectional view of the tire, in the radial region of the coil, whose radial length is defined by the length between the two radial ends of the coil, a sidewall tread with a relative permittivity between 3.5 and 37 is provided, and no rim protector or sidewall core is provided. At least a portion of the near-electric region adjacent to the radial sides of the tire relative to the radial region of the receiving coil, and the length of the tire's radial direction is defined as 15% of the radial length of the tire's radial region, is provided with at least one of a sidewall core and a rim protector having a relative permittivity in the range of 70 to 235.

6. The tire according to claim 1 or 2, wherein, The receiving coil generates electricity by receiving a magnetic field transmitted from a transmitting coil located outside the tire in the tire width direction. In a radial section view of the tire, in the radial region of the coil, whose radial length is defined by the length between the two radial ends of the coil, a sidewall tread with a relative permittivity of 3.5 to 37 is provided, and at least one of a sidewall core and a rim protector with a relative permittivity of 70 to 220 is provided.

7. The tire according to claim 1 or 2, wherein, The receiving coil generates electricity by receiving a magnetic field transmitted from a transmitting coil located outside the tire in the tire width direction. In a radial cross-sectional view of the tire, in the radial region of the coil, whose radial length is defined by the length between the two radial ends of the coil, at least one of a sidewall core and a rim protector with a relative permittivity in the range of 70 to 200 is provided, and no sidewall tread is provided. The relative permittivity of the sidewall tread located radially outside the radial region of the receiving coil is in the range of 3.5 to 40.

8. The tire according to claim 1 or 2, wherein, The difference in relative permittivity between each component disposed in the radial region of the tire and other components adjacent in the tire width direction is less than 170.

9. The tire according to claim 1 or 2, wherein, The receiving coil generates electricity by receiving a magnetic field transmitted from a transmitting coil located outside the tire in the tire width direction. In a radial section view of the tire, the difference in relative permittivity between the member of the radial region of the coil, whose length is defined by the length between the two radial ends of the coil, and other members adjacent to it in the tire width direction is 165 or less.

10. The tire according to claim 1 or 2, wherein, The conductive wire dielectric support layer of the receiving coil is disposed on the inner liner surface that constitutes the inner cavity surface of the tire. The relative permittivity of the support layer, which exists between the conductive wire and the liner in the radial region of the tire, is lower than that of the liner.

11. The tire according to claim 1 or 2, wherein, The receiving coil generates electricity by receiving a magnetic field transmitted from a transmitting coil located outside the tire in the tire width direction. In a radial section view of the tire, the sum of the products of the relative permittivity of each component and the thickness in the tire width direction on a virtual line along the tire width direction at any position within the radial region of the coil, defined by the length between the two ends of the coil in the tire's radial direction, and the relationship between this sum and the shortest distance Dmin from the conductive line of the coil to the liner, falls within the range of equation (1). [Formula 1] 。 12. The tire according to claim 1 or 2, wherein the tire has a sidewall support layer on the inner circumferential side of the tire carcass, the relative permittivity of the sidewall support layer being in the range of 8 to 90, and being lower than the relative permittivity of the rim protector and the sidewall core, whichever has a higher relative permittivity.

13. The tire according to claim 12, wherein, In a radial section view of the tire, in the radial region of the coil, whose radial length is defined by the length between the two ends of the coil in the radial direction of the tire, the maximum value of the thickness of the sidewall support layer in the tire width direction is in the range of 4 mm to 12 mm.

14. A wireless power supply system that provides AC power to a transmitting coil comprising a resonant circuit of a capacitor and a coil, transmits power to a receiving coil comprising a resonant circuit of a capacitor and a coil, and includes the tire of claim 1.

15. The wireless power supply system according to claim 14, wherein, In a radial cross-sectional view of the tire, at least a portion of the receiving coil is located within a power supply area that extends along the winding axis of the supply coil between its two ends in the longitudinal direction.

16. The wireless power supply system according to claim 14 or 15, wherein, The power supply coil is positioned within a 60° radius on either side of the tire circumference, 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 supply coil is mounted on the unsprung component of the vehicle.

18. A tire having a bead core, a sidewall core disposed radially outward of the bead core, a carcass folded back around the bead core, and a belt disposed radially outward of the carcass, wherein a receiving coil is located on an inner surface of the tire cavity, the receiving coil receiving power supplied from outside the tire via an alternating magnetic field. The tire is characterized in that, in a radial cross-sectional view of the tire, the receiving coil is disposed within the radial region of the tire extending from the outermost radial position of the bead core to the innermost radial position of the belt. It has an outer layer of rubber exposed on the tire sidewall in the radial region of the tire. The outer rubber layer contains an anti-aging agent in the amount of 0.5 to 8.0 parts by weight relative to 100 parts by weight of the rubber, and contains wax in the amount of 0.1 to 5.0 parts by weight relative to 100 parts by weight of the rubber.

19. A tire having a bead core, a sidewall core disposed radially outward of the bead core, a carcass folded back around the bead core, and a belt disposed radially outward of the carcass, wherein a receiving coil is located on an inner cavity surface, the receiving coil receiving electricity supplied from outside the tire via an alternating magnetic field. The tire is characterized in that, in a radial cross-sectional view of the tire, in the radial region between the two feet of a perpendicular line drawn from the two ends of the tire radially connected to the inner liner formed on the inner periphery of the tire body, the thermal conductivity λ1 of the inner liner is 0.10 W / m・K or higher.

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