Tire and wireless power supply system

Abstract

To provide a tire which can realize, when a steel cord is used for a belt, excellent power supply efficiency without allowing magnetic field from a power-feeding coil to a power-receiving coil from being disturbed by a metallic component.SOLUTION: A tire includes in a tire meridian cross sectional view: a power-receiving coil (40) which is arranged at a tire radial direction area (WH) from a tire radial direction outermost position (P1) of a bead core (14) to a tire radial direction innermost position (P2) of a belt (20); and an outer layer rubber (26) which is exposed to a tire side face of the tire radial direction area. The outer layer rubber includes 0.5 - 8.0 pts.mass of an antioxidant to 100 pts.mass of the rubber and includes 0.1 - 5.0 pts.mass of a wax to 100 pts.mass of the rubber.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

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

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

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

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

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a tire and a wireless power supply system using the tire that can achieve excellent power supply efficiency without the magnetic field reaching the power reception coil from the power transmission coil being hindered by a metal member existing between the two coils, even when a steel cord is used for the belt.

Means for Solving the Problems

[0006] The tire of the present invention has a bead filler provided on the outer side in the tire radial direction of the bead core, a carcass folded around the bead core, and a belt provided on the outer side in the tire radial direction of the carcass, and is a tire provided with a power receiving coil on the inner cavity surface of the tire for receiving power supplied by an alternating magnetic field from the outside of the tire. In a tire meridian cross-sectional view, the power receiving coil is provided in a tire radial region from the outermost position in the tire radial direction of the bead core to the innermost position in the tire radial direction of the belt, and is provided with an outer layer rubber exposed on the tire side surface of the tire radial region. The outer layer rubber contains 0.5 to 8.0 parts by mass of an anti-aging agent and 0.1 to 5.0 parts by mass of wax with respect to 100 parts by mass of rubber, which is characterized in that.

Advantages of the Invention

[0007] In the tire according to the present invention, improvements have been made to the position of the power receiving coil on the inner cavity surface of the tire. Further, in the tire of the present invention, the contents of the anti-aging agent and wax contained in the outer layer rubber exposed on the tire side surface are limited. As a result, according to the tire according to the present invention, the power supply efficiency can be improved. Further, the tire according to the present invention can suppress a decrease in power supply efficiency while maintaining weather resistance due to long-term use.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0009] Hereinafter, the tire according to the present invention (basic form 1 and additional forms 2 to 6 shown below), and embodiments of the wireless power supply system according to the present invention (basic form 7 and additional forms 8, 9 shown below) will be described in detail with reference to the drawings. Note that these embodiments do not limit the present invention. In addition, the constituent elements of each embodiment include those that can be replaced and are easy for those skilled in the art, or those that are substantially the same. Furthermore, each embodiment can be arbitrarily combined within the scope obvious to those skilled in the art.

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

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

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

[0013] <Tire> [Basic form 1] FIG. 1 is a meridional sectional view showing one side in the tire width direction with respect to the tire equatorial plane (not shown) of the tire according to the present embodiment. In the same figure, the tire portion on the side opposite to the ground contact surface in a state where it is mounted on a rim and a normal internal pressure is applied, and a normal load is applied is shown (hereinafter, the same applies to the invention of the tire).

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

[0015] Further, a rim cushion 24 is provided on the outer side in the tire width direction of the folded-back portion 18b of the carcass 18 provided on the outer side in the tire width direction of the bead core 14 and the bead filler 16. A second filler 25 is provided between the rim cushion 24 and the folded-back portion 18b. On the outer side in the tire radial direction of the rim cushion 24, a side tread 26, a wing tip 28, and a cap tread 30 are sequentially provided. In the bead portion A, a bead reinforcing layer 31 is provided which is folded back at the bead toe 32 from the inner peripheral side of the tire and extends to the intermediate portion in the tire radial direction of the bead filler 16 on the outer peripheral side of the tire.

[0016] In the tire 10 configured as described above, the inner liner 12 is a layer for blocking the gas in contact with the inner cavity surface of the tire. The inner liner 12 can be composed of a single inner liner layer, or can also be composed of a plurality of inner liner layers laminated in the tire radial direction at the tire equatorial plane CP. The inner liner 12 includes at least one layer made of a rubber or resin layer with low air permeability, and as other layers, it can include an adhesive layer at least at the contact portion with the carcass 18.

[0017] The bead core 14 is, for example, a ring-shaped reinforcing material formed by bundling cords, and can have a structure in which a plurality of bead wires made of steel cords or organic fiber cords are coated with rubber. The bead filler 16 is a member for enhancing the rigidity of the bead portion A, and the tire width direction dimension at the inner end portion in the tire radial direction thereof is substantially equal to the tire width direction dimension at the outer end portion in the tire radial direction of the bead core 14, and can have a substantially triangular shape as shown in FIG. 1 in which the tire width direction dimension gradually decreases toward the outer side in the tire radial direction.

[0018] The carcass 18 is a member forming the skeleton of the tire 10, and is composed of at least one carcass layer (carcass ply), and each carcass layer has a configuration in which a plurality of carcass cords are coated with rubber. Generally, steel cords or organic fiber cords are used as the carcass cords. However, in the tire 10 according to the present embodiment, as will be described later, in order to prevent the magnetic field generated so as to penetrate the inner cavity surface of the inner liner 12 substantially perpendicularly in the sidewall portion B from being obstructed by a metal member, it is preferable to use a non-magnetic material as the carcass cord. For example, as the non-magnetic material, organic fibers such as rayon, polyester, polyamide, and aramid can be used.

[0019] The belt 20 is a reinforcing layer provided on the outer side of the carcass 18 in the tire radial direction. It is a member that tightens the carcass 18 to increase the rigidity of the tread portion, improve the handling stability, and reduce the strain deformation to decrease the rolling resistance. The belt 20 can be composed of a plurality of belt layers (two belt layers 20a and 20b in the example shown in FIG. 1) laminated in the tire radial direction in the tread portion D. Each of the belt layers 20a and 20b has a structure in which a plurality of belt cords are coated with rubber. Generally, steel cords or organic fiber cords are used as the belt cords. As the belt cords, not only magnetic materials such as steel cords can be used, but also non-magnetic materials (including paramagnetic materials and diamagnetic materials) can be used.

[0020] The belt cover 22 is a member that reinforces the tightening effect of the carcass 18 by the belt 20, and is particularly a member for preventing the tread portion D from deforming due to the centrifugal force generated during high-speed running of the vehicle. The belt cover 22 can be composed of a plurality of belt cover layers (two belt cover layers 22a and 22b in the example shown in FIG. 1) laminated in the tire radial direction on the outer side of the belt 20 in the tire radial direction. Each of the belt cover layers 22a and 22b has a structure in which a plurality of cords are coated with rubber. Generally, steel cords or organic fiber cords are used as the cords used for the belt cover layer. As this cord, not only magnetic materials such as steel cords can be used, but also non-magnetic materials (including paramagnetic materials and diamagnetic materials) can be used. The bead reinforcing layer 31 is a member that wraps around the folded-back portion 18b of the carcass 18 and contributes to improving the rigidity of the bead portion A, and has a structure in which a plurality of cords made of steel cords or the like are coated with rubber. The tire 10 includes a second carcass 29 between the folded-back portion 18b of the carcass 18 and the bead reinforcing layer 31. The second carcass 29 extends from the bead toe 32 to the tread portion D.

[0021] The rim cushion 24 is provided in a region that contacts the rim flange of a wheel (not shown), and the side tread 26 is arranged so as to connect the rim cushion 24 and the tread portion D. The wing tips 28 are respectively provided at the boundaries between the tread portions D on the left and right of the tire and the side tread 26 in a meridian cross-section view of the tire, and the cap tread 30 is formed on the surface of the tread portion D over the entire contact surface of the tire. The second filler 25 is made of a rubber different from that of the rim cushion 24 and is provided adjacent to the folded-back portion 18b of the carcass 18 as in the illustrated example. By providing the second filler 25, the rigidity of the sidewall portion B can be appropriately improved. Note that any of the rim cushion 24, the second filler 25, the side tread 26, the wing tips 28, and the cap tread 30 can use rubber members conventionally used according to their respective required characteristics.

[0022] On the premise of the existence of the components 12 to 30 of the tire 10 shown above, the tire 10 according to the present embodiment includes a power receiving coil 40 (FIG. 1) that receives AC power transmitted from a power transmission coil (not shown) installed outside the tire 10 on the inner side in the tire width direction of the tire inner cavity surface. The power receiving coil 40 may be provided in contact with the inner liner 12, or may be embedded in the inner liner 12. Further, the power receiving coil 40 may be provided so as to be fixed to the inner liner 12 via a fixing member other than rubber (for example, made of a non-magnetic material, but in particular, a rubber having a relatively high thermal conductivity such as silicone rubber can be used for the fixing portion) (FIG. 1).

[0023] Power supply using the tire 10 according to the present embodiment converts a DC current obtained from an in-vehicle battery (not shown) into an AC current once by an AC power supply device, and applies this AC current to a power transmission coil (for example, attached to the tire-side surface of a knuckle, which is a component of a vehicle's steering axle). By doing so, an AC magnetic field is generated around the power transmission coil. When this AC magnetic field intersects the power receiving coil 40, an induced electromotive force is generated in the power receiving coil 40 and power is supplied.

[0024] In realizing such power supply, in the tire 10 according to the present embodiment, in a tire meridian cross-sectional view (FIG. 1), the power receiving coil 40 is provided in a tire radial direction region WH from the outermost position P1 in the tire radial direction of the bead core 14 to the innermost position P2 in the tire radial direction of the belt 20. Further, the power receiving coil 40 is provided in a region on the outer side in the tire width direction from the innermost position P2 in the tire radial direction.

[0025] More specifically, the tire radial direction region WH is a tire radial direction region defined by the radially outer end (point P1) of the bead core 14 that may contain a ferromagnetic material and the innermost position in the tire radial direction (point P2, the outer end in the tire width direction of the belt 20) of the belt 20 that may contain a ferromagnetic material, and is a region radially outside point P1 and radially inside point P2. In the tire radial direction region WH, since the tire 10 is curved in a shape convex outward, when the power receiving coil 40 is provided in the tire radial direction region WH, the power receiving coil 40 will basically be arranged outside the outer end (point P2) in the tire width direction of the belt 20 in the tire width direction. However, when point P1 is clearly inside the tire width direction of point P2 and the power receiving coil 40 is arranged near the bead core 14, it may be arranged inside the outer end (point P2) in the tire width direction of the belt 20 in the tire width direction. Further, when point P1 is clearly outside the tire width direction of point P2 and the power receiving coil 40 is arranged near the belt 20, it may be arranged inside the tire width direction of the radially outer end (point P1) of the bead core 14 in the tire width direction.

[0026] The tire side surface is the tire surface that can be visually recognized from the outside opposite to the inner cavity surface of the tire in the tire radial region WH. The outer layer rubber exposed on the tire side surface contains 0.5 to 8.0 parts by mass of an anti-aging agent and 0.1 to 5.0 parts by mass of wax based on 100 parts by mass of the rubber. In the case of this embodiment, the outer layer rubber exposed on the tire side surface includes the rim cushion 24, the side tread 26, and the wing tip 28. That is, at least a part of the rim cushion 24, the side tread 26, and the wing tip 28 is exposed on the tire side surface, and contains 5.0 to 8.0 parts by mass of an anti-aging agent and 0.1 to 5.0 parts by mass of wax based on 100 parts by mass of the rubber.

[0027] Generally, rubber may deteriorate and cracks may occur when it is exposed to an ultraviolet and oxygen atmosphere. In contrast, rubber can suppress the occurrence of deterioration and cracks by containing an anti-aging agent and wax.

[0028] By containing 0.5 parts by mass or more of an anti-aging agent and 0.1 parts by mass or more of wax based on 100 parts by mass of the rubber, the tire 10 can suppress the deterioration of the rubber and the occurrence of cracks. On the other hand, the tire can suppress the precipitation of the anti-aging agent and wax on the tire side surface due to long-term use by having 8.0 parts by mass or less of the contained anti-aging agent and 5.0 parts by mass or less of wax based on 100 parts by mass of the rubber, respectively.

[0029] The anti-aging agent is preferably an amine-based anti-aging agent. Examples of the anti-aging agent 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-toluenesulfonylamide)diphenylamine, and N-phenyl-N′-(3-methacryloyloxy-2-hydroxypropyl)-p-phenylenediamine.

[0030] The content of the anti-aging agent can be measured, for example, by gas chromatography in accordance with JIS K6229 and JIS K0114 as follows. That is, a new tire that has not been run is disassembled, and after thinly slicing the outer rubber layers respectively, it is cut into test pieces about 30 mm long and 1 mm square, extracted with acetone for 8 hours, and the obtained filtrate is returned to room temperature to be used as a gas chromatograph measurement sample. Also, a solution (standard sample) with four concentrations in the range of 100 ppm to 1000 ppm of the anti-aging agent to be measured is prepared. Then, the area of the obtained gas chromatograph measurement sample is determined, and the content of the anti-aging agent in the gas chromatograph measurement sample is calculated using a calibration curve.

[0031] Wax means a substance that has malleability at ambient temperature, has a relatively low viscosity when melted, is insoluble in water, and is hydrophobic. Examples of waxes include petroleum waxes such as paraffin wax and microcrystalline wax; natural waxes such as plant waxes and animal waxes; and synthetic waxes such as polymers of ethylene, propylene, etc. These may be used alone or in combination of two or more.

[0032] The content of the wax can be measured, for example, by the method in accordance with JIS K6229 as follows. That is, a new tire that has not been run is disassembled, and after thinly slicing the outer rubber layers respectively, it is cut into test pieces about 30 mm long and 1 mm square, extracted with acetone for 8 hours, and the obtained filtrate is cooled (temperature <0 °C) to precipitate the wax. Then, the content of the wax is determined from the precipitated weight and the sample weight.

[0033] (Function, etc.) As described above, a wireless power reception system that supplies power between a power transmission coil buried near a road surface and a power reception coil attached on the center line in the tire width direction of a wheel has been conventionally known (Patent Document 1, FIG. 1). In this wireless power reception system, the magnetic field reaching the power reception coil from the power transmission coil may be affected by the belt. For example, in this wireless power reception system, when a metal belt cord (limited to a magnetic material) is used for the belt, a part of the magnetic field that should reach the power reception coil from the power transmission coil may be blocked by the magnetic material (belt cord) contained in the belt, and as a result, excellent power supply efficiency may not be achieved.

[0034] Therefore, even when a metal belt cord is used for the belt 20 shown in FIG. 1, the inventors have earnestly studied a tire 10 that can realize excellent power supply efficiency without a part of the magnetic field that should reach the power reception coil 40 from the power transmission coil being blocked by the components of the tire 10 including a magnetic material existing between these two coils.

[0035] Specifically, the inventors earnestly studied at what position the power reception coil 40 provided on the inner side in the tire width direction of the inner cavity surface of the tire 10 should be formed with respect to the power transmission coil (not shown) provided outside the tire 10.

[0036] First, in FIG. 1, the inventors focused on a plurality of line segments that reach from each point (starting point) on the inner cavity surface of the tire to each point (ending point) on the outer surface of the tire at the shortest distance, and extracted a region composed of a plurality of line segments that do not include the belt 20 from among these line segments. By providing the power reception coil 40 so as not to deviate from the inner cavity surface of the tire included in this region, the inventors obtained the finding that most of the magnetic field generated between the two coils is not blocked by the belt 20 that may contain a magnetic material.

[0037] Next, in view of the above finding being for defining the radially outer end portion of the installation region of the power receiving coil 40, the inventors of the present invention also earnestly studied how to define the radially inner end portion of this installation region. As a result, the inventors focused on the bead core 14 that might be composed of a metal member, extracted a region composed of a plurality of line segments that do not include the bead core 14 among the above line segments, and provided the power receiving coil 40 so as not to deviate from the tire inner cavity surface included in this region. Thus, the inventors also obtained the finding that most of the magnetic field generated between the two coils would not be blocked by the bead core 14 that might contain a magnetic material.

[0038] Based on the above findings, in the tire 10 according to the present embodiment, the power receiving coil 40 is provided in the tire radial direction region WH from the radially outermost position P1 of the bead core 14 to the radially innermost position P2 of the belt 20. Thereby, according to the tire 10 of the present embodiment, since no excessive component of the tire 10 that might contain a magnetic material is provided between the power transmission coil and the power receiving coil 40, the power supply efficiency can be improved.

[0039] Next, during tire rolling, iron powder is generated from the brake rotor and brake pads when braking. The iron powder causes a part of the magnetic field that should reach the power receiving coil from the power transmission coil to be blocked in the wireless power receiving system. Therefore, the inventors earnestly studied a method for suppressing the influence of the iron powder generated from the brake rotor and brake pads on the power receiving system.

[0040] Specifically, the inventors obtained the finding that due to aging, the anti-aging agent and wax contained in the rubber are deposited on the tire surface, and the iron powder generated from the brake rotor and brake pads easily adheres to the deposited anti-aging agent and wax.

[0041] Based on the above findings, for the tire 10 according to the present embodiment, the anti-aging agent and wax contained in the outer layer rubber are respectively limited to 0.5 to 8.0 parts by mass and 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the rubber. Since the contents of the anti-aging agent and wax in the outer layer rubber of the tire 10 are within the above ranges, it is possible to suppress the precipitation amount of the anti-aging agent and wax while maintaining the performance as the outer layer rubber. Thereby, according to the tire 10 according to the present embodiment, since the precipitation amount of the anti-aging agent and wax deposited on the tire side surface is suppressed, it is difficult for iron powder to adhere to the tire side surface. Therefore, even with aging use, the tire 10 can suppress a decrease in the power transmission power supply efficiency.

[0042] In addition, it is more preferable that the anti-aging agent contains 0.7 to 7.8 parts by mass, and extremely preferably 0.8 to 7.5 parts by mass with respect to 100 parts by mass of the rubber. Also, it is more preferable that the wax contains 0.2 to 4.8 parts by mass, and further preferably 0.3 to 4.5 parts by mass with respect to 100 parts by mass of the rubber.

[0043] FIG. 2 is a meridian cross-sectional view showing a modified example of the tire according to the present embodiment. In the present embodiment, instead of the tire 10 shown in FIG. 1, the tire 10A shown in FIG. 2 can also be adopted. As shown in FIG. 2, the tire 10A is a run-flat tire in which a run-flat liner 27 is provided on the outer side in the tire width direction of the inner liner 12 mainly in the sidewall portion B. The run-flat liner 27 is formed between the inner liner 12 and the carcass 18 at least over the sidewall portion B and the shoulder portion C. In addition, even when the run-flat liner 27 is provided, the power receiving coil 40 can be provided on the inner peripheral side of the inner liner 12. Further, in the example shown in FIG. 2, the carcass 19 is composed of two carcass plies 19a and 19b. The carcass ply 19a terminates at the upper part in the tire radial direction of the run-flat liner 27, while the carcass ply 19b terminates at the central part in the tire radial direction of the bead filler 16.

[0044] For both of the tires 10 and 10A shown in FIGS. 1 and 2, the power receiving coil 40 may be provided on the inner cavity surface of the tire via a support layer (not shown) provided between the power receiving coil 40 and the inner cavity surface of the tire (formed by the inner liner 12). The support layer is a plate-like member having a predetermined thickness and is formed of an insulating material, such as rubber or synthetic resin. The outer side of the support layer in the tire width direction may be adhered to the inner liner 12 with an adhesive. The inner side of the support layer in the tire width direction is provided with the power receiving coil. The power receiving coil may be adhered to the support layer with an adhesive. In another example, the power receiving coil 40 may be covered by a coating layer. The coating layer may be formed of the same material as the support layer or a different material. In this case, the support layer, the power receiving coil 40, and the coating layer are arranged in order from the outer side in the tire width direction to the inner side in the tire width direction and are integrated with the inner cavity surface of the tire. The power receiving coil 40 is sandwiched between the support layer and the coating layer. Further, in another example, the power receiving coil 40 may be embedded in the support layer. In this case, the support layer has a thickness sufficient to cover the power receiving coil 40.

[0045] (Additional Form 2) In Basic Form 1, it is preferable that the thickness t of the outer layer rubber is 2.5 to 20.0 mm (Additional Form 2), more preferably 2.7 to 18.0 mm, and extremely preferably 2.9 to 16.0 mm. The outer layer rubber in the tire radial region WH includes the rim cushion 24, the side tread 26, and the wing tip 28. The thickness t of the outer layer rubber refers to the length in the direction perpendicular to the outer surface of the carcass 18 in the tire width direction, that is, the outer surface of the folded-back portion 18b in the tire width direction, as shown in FIG. 1. The thickness t of the outer layer rubber changes in the tire radial direction as shown in FIG. 1. That is, it is preferable that the thickness t of the outer layer rubber is within the above range at any location.

[0046] By having the thickness t of the outer layer rubber of the tire 10 within the above range, while maintaining the performance as the outer layer rubber, it is possible to prevent the contents of the anti-aging agent and the wax from becoming excessive and more reliably suppress the precipitation amount of the anti-aging agent and the wax.

[0047] If the thickness t of the outer layer rubber of the tire 10 is too large, the contents of the anti-aging agent and wax as the entire outer layer rubber will be excessive. On the other hand, if the thickness t of the outer layer rubber of the tire 10 is too small, it will be difficult to maintain the performance of the outer layer rubber.

[0048] (Additional Form 3) FIG. 3 is a meridian cross-sectional view for explaining the amount of deflection in the tire width direction of the tire according to the present embodiment. In the basic form 1 or the form obtained by adding the additional form 2 to the basic form 1, as shown in FIG. 3, in the tire 10 mounted on a specified rim and applied with a normal internal pressure, the length SH (mm) in the tire radial direction from the bead toe 32 to the tread surface 34 of the tire 10 in the unloaded state, and the amount of deflection D in the tire width direction before and after applying a load corresponding to 80% of the normal load to the tire 10 preferably satisfy the following formula (1) (Additional Form 3). 0.0278×SH - 1.33 ≦ D ≦ 0.286×SH - 13.7 ···(1)

[0049] The meridian cross-section shown by the broken line in FIG. 3 shows the tire 10 in the unloaded state mounted on a specified rim and applied with a normal internal pressure. Let the length in the tire radial direction from the bead toe 32 in the unloaded state to the tread surface 34 at the ground contact center (also referred to as the tire section height) be SH (mm). Also, let the length in the tire width direction of the tire in the unloaded state be D1. The meridian cross-section shown by the solid line in FIG. 2 shows the tire 10 after applying a load corresponding to 80% of the normal load to the tire 10 mounted on a specified rim and applied with a normal internal pressure. Let the length in the tire width direction at the ground contact center after applying a load corresponding to 80% of the normal load be D2.

[0050] The amount of deflection D in the tire width direction before and after applying a load corresponding to 80% of the normal load to the tire is the difference (D2 - D1) between the length D1 in the tire width direction of the tire in the unloaded state and the length D2 in the tire width direction after applying a load corresponding to 80% of the normal load.

[0051] The tire 10 preferably has a JIS hardness of 65 or more, more preferably 8% or more, and extremely preferably 10% or more of the cross-sectional area of the tire radial region WH among the rubber disposed in the tire radial region WH in a tire meridian cross-sectional view. The rubber disposed in the tire radial region WH includes a bead filler 16, a rim cushion 24, (a second filler 25), and a side tread 26. The JIS hardness is a durometer hardness measured under the condition of a temperature of 23°C using a type A durometer in accordance with JIS-K6253.

[0052] By having the deflection amount D within the range represented by the above formula (1), the tire 10 suppresses the deformation of the tire side surface centered on the sidewall portion B while maintaining the tire performance during tire rolling. By suppressing the deformation of the tire side surface, the tire 10 can suppress the precipitation of an anti-aging agent and wax from the rubber on the tire side surface.

[0053] When the deformation amount of the tire side surface of the tire 10 is too large, that is, when the tire 10 is easily deformed, the anti-aging agent and wax are likely to precipitate from the rubber on the tire side surface due to repeated deformation. Further, when the deformation amount of the tire side surface is too large, the power receiving coil provided on the inner cavity surface of the tire in the tire radial region WH is likely to fall off from the inner cavity surface of the tire.

[0054] In the above formula (1), it is more preferable that the deflection amount D satisfies 0.0278×SH - 1.31 ≤ D, and extremely preferably 0.0278×SH - 1.29 ≤ D. Similarly, it is more preferable that the deflection amount D satisfies D ≤ 0.286×SH - 13.9, and extremely preferably D ≤ 0.286×SH - 14.1.

[0055] (Additional Form 4) In the basic form 1 or the form obtained by adding at least one of the additional forms 2 and 3 to the basic form 1, the cross-sectional area S of the outer layer rubber o and the 100% modulus M oThe sum of the products with and the cross-sectional area S of the inner rubber layer that is disposed on the inner side in the tire width direction of the outer rubber layer and does not expose to the tire side surface i and the 100% modulus M i The sum of the products with satisfies the following formula (2) (Additional form 4) is preferable.

[0056] [Number]

[0057] The cross-sectional area is the cross-sectional area of the rubber in the meridian section. The inner rubber layer is the bead filler 16 and the second filler 25. The inner rubber layer does not include the inner liner 12 and the carcass 18. In the tire of FIG. 1, the cross-sectional area S of the outer rubber layer ok is the cross-sectional area S of the rim cushion 24 in the range of the tire radial direction region WH o1 , the cross-sectional area S of the side tread 26 o2 and the cross-sectional area S of the wing tip 28 o3 . The cross-sectional area S of the inner rubber layer ik is the cross-sectional area S of the bead filler 16 in the range of the tire radial direction region WH i1 and the cross-sectional area S of the second filler 25 i2 .

[0058] The 100% modulus is the tensile stress when a 100% elongation is given. The 100% modulus can be measured by the following procedure. First, a JIS No. 3 dumbbell-shaped test piece is cut out from the rubber test pieces obtained from each part of the tire in accordance with JIS K6251. Next, the 100% deformation stress is measured in accordance with JIS K6251. The measured value of the 100% deformation stress is taken as the measured value of the 100% modulus.

[0059] The 100% modulus M of the outer rubber layer ok is the measured value M of the rim cushion 24 o1 , the measured value M of the side tread 26 o2 and the measured value M of the wing tip 28 o3 . The 100% modulus M of the inner rubber layer ik is the measured value M of the bead filler 16 i1and the measured value M of the second filler 25 i2 is as follows.

[0060] The cross-sectional area S of the outer rubber in the above formula (2) o and the 100% modulus M o The sum of the products is the load required for the outer rubber to deform by 100% (hereinafter referred to as the "outer rubber load"). Similarly, the cross-sectional area S of the inner rubber i and the 100% modulus M i The sum of the products is the load required for the inner rubber to deform by 100% (hereinafter referred to as the "inner rubber load"). The value obtained by dividing the inner rubber load by the outer rubber load is called the load index in this specification.

[0061] When the load index is within the range of the above formula (2), the tire can suppress the deformation of the tire sidewall, suppress the precipitation of the anti-aging agent and wax from the rubber on the tire sidewall, and ensure the cut resistance of the outer rubber. When the load index is smaller than the above range, the rigidity of the inner rubber is insufficient, so the deformation amount of the tire becomes excessively large, or the volume of the outer rubber becomes excessively large, increasing the precipitation amount of the anti-aging agent and wax. On the other hand, when the load index is larger than the above range, the thickness of the outer rubber becomes too small, reducing the cut resistance on the tire sidewall.

[0062] By satisfying the above load index with the above formula (2), while maintaining the tire performance during tire rolling, the deformation of the tire sidewall centered on the sidewall portion B is suppressed. Therefore, while maintaining the function of the tire 10, the deformation amount of the tire 10 is suppressed, so that the precipitation amount of the anti-aging agent and wax can be suppressed.

[0063] It should be noted that the value of the above load index is more preferably 0.35 or more and 6.5 or less, and extremely preferably 0.4 or more and 6.0 or less. In the case of the tire 10A including the run-flat liner 27 shown in FIG. 2, the inner rubber is the bead filler 16, the second filler 25, and the run-flat liner 27.

[0064] (Additional Form 5) In the basic form 1 or the form obtained by adding at least any one of the additional forms 2 to 4 to the basic form 1, it is preferable that the height of the unevenness on the surface of the outer layer rubber is 2.0 mm or less (additional form 5).

[0065] The tire 10 may have, for example, embossing, decoration, serration, and decorative patterns as unevenness on the surface of the outer layer rubber, that is, on the tire sidewall. The height of the unevenness formed on the surface of the outer layer rubber (tire sidewall) of the tire 10 is 2.0 mm or less. The unevenness is a surface shape having mountains and valleys. The height of the unevenness refers to the length in the thickness direction of the outer layer rubber between the position where the mountain height is maximum and the position where the valley depth is maximum. Since the height of the above-mentioned unevenness of the tire 10 is 2.0 mm or less, iron powder is less likely to accumulate in the uneven portion. Therefore, in the tire 10, the adhesion of iron powder to the uneven portion on the tire sidewall is suppressed. Note that the lug grooves (not shown) formed in the shoulder portion C are not included in the above-mentioned unevenness. This is because the shoulder portion C is in the vicinity of the belt 20, and even if iron powder accumulates in the lug grooves formed in the shoulder portion C, the influence on the power feeding efficiency is small.

[0066] (Additional form 6) In the basic form 1 or the form obtained by adding at least any one of the additional forms 2 to 5 to the basic form 1, the power receiving coil 40 generates electric power by receiving the magnetic field transmitted from the power transmitting coil disposed outside the tire in the tire width direction of the power receiving coil 40. In the tire meridian cross-sectional view (FIG. 1), in the power receiving coil radial region R1 defined by the length in the tire radial direction between both ends of the power receiving coil 40 in the tire radial direction, and in the power receiving vicinity regions R2 adjacent to both sides in the tire radial direction with respect to the power receiving coil radial region R1 and defined by 15% of the length in the tire radial direction of the tire radial region WH, the outer layer rubber contains 0.5 to 7.5 parts by mass of an anti-aging agent with respect to 100 parts by mass of the rubber and 0.1 to 4.5 parts by mass of wax with respect to 100 parts by mass of the rubber, and it is preferable that the height of the unevenness on the surface of the outer layer rubber is 1.5 mm or less (additional form 6).

[0067] The tire 10 can more reliably suppress the deposition amount of the anti-aging agent and the wax while maintaining the performance as the outer layer rubber because the content of the anti-aging agent and the wax in the outer layer rubber in the power receiving region AR is within the above range. Further, since the height of the unevenness on the surface of the outer layer rubber of the tire 10 is within the above range, it is difficult for iron powder to accumulate in the uneven portions, so that it is more reliably suppressed that iron powder adheres to the uneven portions on the side surface of the tire. Therefore, the tire 10 more reliably suppresses the adhesion of iron powder to the side surface of the power receiving region AR.

[0068] The outer layer rubber included in the power receiving region AR varies depending on the position where the power receiving coil 40 is installed. In the tire 10 shown in FIG. 1, the outer layer rubber included in the power receiving region AR is the side tread 26. When the power receiving coil 40 is installed at a position radially outside the tire diameter than the position shown in FIG. 1, the outer layer rubber included in the power receiving region AR includes the side tread 26 and the wing tip 28. When the power receiving coil 40 is installed at a position radially inside the tire diameter than the position shown in FIG. 1, the outer layer rubber included in the power receiving region AR includes the side tread 26 and the rim cushion 24. Further, when the power receiving coil 40 is installed in a wider range in the tire diameter direction than the range shown in FIG. 1, the outer layer rubber included in the power receiving region AR includes the rim cushion 24, the side tread 26, and the wing tip 28.

[0069] <Wireless power supply system> [Basic form 7] Figure 4 shows a wireless power supply system 50 according to this embodiment, including a power transmission coil 52 and a tire 10B provided with a power reception coil 40 (a portion on one side in the tire width direction with reference to the tire equatorial plane CP in a tire meridian cross-sectional view). The tire 10B is different from the tire 10 shown in FIG. 1 in that the second filler 25 is omitted. The rim cushion 24 of the tire 10B is in contact with the folded portion 18b of the carcass 18. In the same figure, a tire portion on the side opposite to the ground contact surface is shown in a state where the rim is assembled and normal internal pressure is applied, and a load of 80% of the normal load is applied (hereinafter, the same applies to the invention of the wireless power supply system). The wireless power supply system 50 will be described for the case of being applied to the tire 10B, but the present invention is not limited to this, and it goes without saying that it is applicable to the tire 10 and the tire 10A.

[0070] The power transmission coil 52 shown in the figure constitutes a resonance circuit with a capacitor and a coil, and is attached to the surface on the tire side of a knuckle or a hub carrier, which is a component of a steering axle of a vehicle (not shown), or any component constituting a strut structure.

[0071] Next, the power reception coil 40 shown in FIG. 4 has the same configuration as the power reception coil shown in FIG. 1, and constitutes a resonance circuit with a capacitor and a coil. The tire 10B shown in FIG. 4 is a tire in which at least one of the basic form 1 of the tire related to the above-described tire 10 and the additional forms 2 to 6 is added, and its actions, functions, etc. are as described above.

[0072] Under such a premise, the wireless power supply system 50 according to this embodiment is wireless power supply using a magnetic field resonance method using an alternating magnetic field. As shown in FIG. 4, power is supplied to the power transmission coil 52, and power is transmitted to the power reception coil 40 by the alternating magnetic field. According to such a wireless power supply system 50, as described above, the power supply efficiency can be improved.

[0073] Here, in order to drive the sensors and the accompanying electric circuits installed inside the tire 10B, it is preferable to transmit power at a frequency of 1 to 20 MHz with a power of 0.1 to 15 W. More preferably, the power transmission coil 52 is supplied with AC power having a frequency of 6.78 to 13.56 MHz.

[0074] In addition, the shortest distance between the power transmission coil 52 and the power reception coil 40 (hereinafter, may be referred to as "transmission gap G") is preferably 10 mm or more and 80 mm or less. Here, the transmission gap G is a value measured in a state where the tire 10B is rim-mounted, normal internal pressure is applied, and the vehicle is attached and stopped on flat ground. Further, the transmission gap G refers to the shortest distance between the power transmission coil 52 and the power reception coil 40, that is, in FIG. 4, the distance between the innermost position in the tire width direction of the power transmission coil 52 and the outermost position in the tire width direction of the power reception coil 40.

[0075] By setting the transmission gap G to 10 mm or more, it is possible to suppress the power reception power fluctuation rate from becoming excessive due to the fluctuation of the relative position between the power transmission coil 52 and the power reception coil 40 shown in FIG. 4 in the power transmission direction, and the circuit configuration connected to the power reception coil 40 can be made simple, and thus stable power can be easily supplied to the electronic device. Here, the fluctuation of the power reception power depends on the fact that during the rolling of the tire 10, the tire 10 expands slightly due to centrifugal force, and the relative position between the two coils 52 and 40 fluctuates. Specifically, the higher the tire rolling speed, the more the tire 10 expands in the tire diameter direction, and the power reception coil 40 moves to the outside in the tire diameter direction (the upper side in FIG. 4), while the position of the power transmission coil 52 remains unchanged, so the relative position between the two coils 52 and 40 changes.

[0076] On the other hand, by setting the transmission gap G to 80 mm or less, the strength of the magnetic field generated between the two coils 52 and 40 does not become excessively small, and power feeding by the alternating magnetic field can be efficiently performed.

[0077] Note that the transmission gap G is more preferably 12 mm or more and 75 mm or less, and extremely preferably 15 mm or more and 70 mm or less.

[0078] By adopting the range of the transmission gap G, the power range, and the frequency band as described above, not only can the temperature rise of the power receiving coil 40 be suppressed, but also an increase in the number of turns of the coil etc. (and thus an increase in the coil weight) is not required, so that the rolling resistance of the tire is not increased, and power feeding can be efficiently performed, and thus excellent power feeding efficiency can be realized. In particular, according to the range of the transmission gap G described above, excellent power feeding efficiency can be obtained when power is transmitted using the tire structure in magnetic field resonance type wireless power feeding in the above frequency band.

[0079] Note that in the example shown in FIG. 4, the power transmission coil 52 is arranged so as to extend in the tire diameter direction, but the present embodiment is not limited to such an arrangement form. That is, as long as the above-described transmission gap G is within a predetermined range, the extending direction of the power transmission coil 52 may be inclined with respect to the tire diameter direction.

[0080] [Additional Form 8] FIG. 5 is a diagram showing that the power receiving coil 40 is located within the power feeding region of the power transmission coil 52 for the wireless power feeding system 50 according to the present embodiment. (A) and (B) show examples where the power feeding direction is the tire width direction, and (C) and (D) show examples where the power feeding direction is inclined downward with respect to the tire width direction. In FIG. 5, (A) and (C) are examples where the inner part in the tire diameter direction of the power receiving coil 40 is included in the power feeding region of the power transmission coil 52, and (B) and (D) are examples where the outer part in the tire diameter direction of the power receiving coil 40 is included in the power feeding region of the power transmission coil 52.

[0081] In the basic form 7, as shown in FIGS. 5(A) to 5(D), in the tire meridian cross-sectional view, at least a part of the power receiving coil 40 is preferably located in the power supply region extending in the winding axis direction of the power transmission coil 52 between both longitudinal ends of the power transmission coil 52 (additional form 8). Here, the positional relationship between the power receiving coil 40 and the power transmission coil 52 is measured in a state where the tire 10B is rim-mounted, a normal internal pressure is applied, and the vehicle is mounted and stopped on a flat ground. More preferably, the power transmission coil radial region defined by the length between both tire radial ends of the power transmission coil 52 is preferably arranged so as to overlap at least a part of the power receiving coil radial region R1. With such an arrangement, higher power supply efficiency can be achieved.

[0082] The power transmission coils 52 shown in FIGS. 5(A) and 5(B) are arranged at positions corresponding to a part of the region in the tire circumferential direction on the outer side in the tire width direction. The power receiving coil 40 provided on the inner cavity surface of the tire extends over the entire circumference in the tire circumferential direction. At least a part of the power receiving coil 40 is provided in the region where the power transmission coil radial region is projected onto the inner cavity surface of the tire, that is, the region between the points where the virtual lines parallel to the winding axis of the power transmission coil 52 extending from the outer tire radial end and the inner tire radial end of the power transmission coil 52 intersect the inner cavity surface of the tire. The power receiving coil 40 provided on the inner cavity surface of the tire is preferably such that a part of the power receiving coil 40 in the tire radial direction is included in the region where the above power transmission coil radial region is projected, and more preferably, the entire power receiving coil 40 in the tire radial direction is included in the region where the above power transmission coil radial region is projected.

[0083] In the wireless power supply system 50 according to the present embodiment, the power transmission coil 52 is attached to the surface on the tire side of a knuckle or a hub carrier (located on the outer side in the tire width direction of the sidewall portion B) which is a component of the steering axle of the vehicle, or any component constituting the strut structure. Therefore, when considering the power supply efficiency in consideration of the shape of the tire, particularly the sidewall portion B of the tire 10B, as shown in FIGS. 5(A) and 5(B), it is desirable that the direction of the magnetic field lines penetrating the tire in the sidewall portion B, and thus the power supply direction Dp, be substantially in the tire width direction.

[0084] In line with such findings, as shown in FIGS. 5(A) and 5(B), when the power supply direction Dp is substantially in the tire width direction, power supply can be performed more efficiently, and thus excellent power supply efficiency can be achieved.

[0085] Also, in the examples shown in FIGS. 5(B) and 5(C), for each of the power transmission coil 52 and the power reception coil 40, since the constituent surfaces (the planes perpendicular to the winding axes of the respective coils in FIGS. 5(B) and 5(C)) are parallel to each other, compared with the examples shown in FIGS. 5(A) and 5(D), power supply can be performed more efficiently, and thus excellent transmission efficiency can be achieved.

[0086] Note that, as shown in FIGS. 5(A) and 5(D), the power transmission coil 52 and the power reception coil 40 do not necessarily have their constituent surfaces parallel to each other. The reason is that if the magnetic field generated by the power transmission coil 52 links the power reception coil 40, an electromotive force is generated by the alternating magnetic field, and there is no restriction on the relative orientation between the above-mentioned surfaces.

[0087] [Additional Mode 9] FIG. 6 is a diagram showing the installation position of the power transmission coil 52 with respect to the wireless power supply system 50 according to the present embodiment.

[0088] In the basic mode 7 or the mode obtained by adding the additional mode 8 to the basic mode 7, as shown in FIG. 6, it is preferable that the power transmission coil 52 is installed within a range of 60° on both sides in the tire circumferential direction centered on an imaginary line extending vertically upward from the tire center O (Additional Mode 9).

[0089] Generally, when the tire 10B rolls, the power receiving coil 40 deforms along with the deformation at the grounding portion of the tire 10B. On the other hand, at the portion away from the grounding portion of the tire 10B (the upper portion of the tire 10B in FIG. 6), almost no deformation of the power receiving coil 40 due to the tire deformation is observed. For this reason, by installing the power transmission coil 52 arranged outside the tire 10B in the vicinity of the upper part of the tire away from the installation portion of the tire 10B (the tire circumferential direction range R of 60° on both sides of the virtual line extending vertically upward from the tire center O), when the tire rolls, the fluctuation of the above-described transmission gap G can be suppressed, power supply can be performed more efficiently, and thus more excellent power supply efficiency can be realized. Note that the example shown in FIG. 6 is an example in which the power transmission coil 52 is attached to the wheel house 54, and the tire circumferential direction range R described above is applied within the wheel house 54.

[0090] Note that it is more preferable that the power transmission coil 52 is installed in the tire circumferential direction range of 55° on both sides of the virtual line extending vertically upward from the tire center O, and it is extremely preferable that the power transmission coil 52 is installed in the tire circumferential direction range of 50° on both sides of the virtual line.

[0091] Also, the shape of the power transmission coil 52 is not particularly limited. However, when the power transmission coil 52 is installed in the wheel house, for example, it is preferable to use a so-called spiral coil that can reduce the thickness as a whole.

[0092] [Additional Form 10] FIG. 7 is a schematic diagram showing the position where the power transmission coil is installed in the tire shown in FIG. 1.

[0093] In the basic form 7 or the form obtained by adding at least any one of the additional forms 8 and 9 to the basic form 7, it is preferable that the power transmission coil 52 is installed on the lower spring member of the vehicle (Additional Form 10).

[0094] The spring lower member includes, for example, a knuckle, a brake caliper, and a damper case of a strut suspension. By providing the power transmission coil 52 on the spring lower member, even when the vehicle moves up and down due to unevenness of the road surface, the distance between the power transmission coil 52 and the power reception coil 40 provided on the tire 10 can be kept constant.

[0095] FIGS. 7(A), (B) and FIG. 8 are diagrams showing the positions where the power transmission coil 52 is installed in the wireless power supply system 50 shown in FIG. 4. As shown in FIGS. 7(A) and 7(B), the power transmission coil 52 may be provided in the damper case 60 of the strut suspension. FIG. 7(A) shows an example in which the power transmission coil 52 is provided in the damper case 60 of the front wheel, and FIG. 7(B) shows an example in which the power transmission coil 52 is provided in the damper case 60 of the rear wheel. Thereby, even when the tire 10 moves up and down due to unevenness of the road surface, the power transmission coil 52 faces the power reception coil 40 in the tire width direction, avoids the belt 20 and the bead core 14, and can transmit power in the tire width direction. Therefore, the wireless power supply system 50 can improve the power supply efficiency.

[0096] Further, the power transmission coil 52 may be provided on a member that moves together with the tire 10 in conjunction with steering, such as a knuckle of a multi-link type suspension. FIG. 8 shows a front wheel of a multi-link type suspension, and the knuckle 70 changes its orientation together with the tire 10 with respect to the upper arm 72 in conjunction with steering. Thereby, even during steering, the distance between the power transmission coil 52 and the power reception coil 40 provided on the tire 10B can be kept constant. Therefore, the tire 10B can be stably powered during vehicle travel.

[0097] <Other embodiments of the tire and the wireless power supply system> The above is the description of the tire and the wireless power supply system according to the present invention. Hereinafter, other matters regarding the tire and the wireless power supply system according to the present invention will be listed.

[0098] The carbon content of the inner liner 12, which is a component of the tire 10B, is 45 to 75 parts by mass (parts by mass when the rubber is 100, the same hereinafter), the carbon content of the side tread is 25 to 65 parts by mass, the carbon content of the rim cushion is 50 to 80 parts by mass, the carbon content of the bead filler 16 is 40 to 80 parts by mass, the carbon content of the covering rubber of the carcass 18 is 35 to 70 parts by mass, and the carbon content of the run-flat liner 27 is preferably 45 to 75 parts by mass. By adopting these respective compounding amounts, it is possible to realize high power feeding efficiency while realizing desired rubber physical properties in each rubber layer. Usually, carbon compounded in rubber has an ultraviolet absorption ability in addition to the reinforcing effect and has an effect of suppressing the deterioration of rubber. Therefore, even when the compounding amounts of the anti-aging agent and wax are reduced, the weather resistance of the tire can be maintained, the decrease in power feeding efficiency can be suppressed, and it is most preferable because it is easy to achieve compatibility with the characteristics of the rubber required for the tire.

[0099] Regarding the wireless power feeding system 50 shown in FIG. 4, the power receiving coil 40 is preferably provided in the tire inner cavity of the sidewall portion B of the tire 10B so that the configuration surface faces in the tire width direction. As described above, as shown in FIGS. 5(A) and (B), when the power feeding direction by the power transmitting coil 52 is substantially in the tire width direction, by providing the power receiving coil 40 so that its configuration surface faces in the tire width direction, the power transmitting surface of the power transmitting coil 52 and the configuration surface of the power receiving coil 40 become parallel. Thereby, power feeding can be performed more efficiently, and thus excellent power feeding efficiency can be realized.

[0100] FIG. 9 is a diagram showing the arrangement mode of the power receiving coil 40. (A) to (F) are examples showing the power receiving coil 40 composed of 2 sets, 3 sets, 4 sets, 5 sets, 6 sets, and 8 sets of power receiving coil elements 40a respectively, (G) is an example in which a plurality of power receiving coil elements 40a are laminated in the tire radial direction, and (H) is an example in which a part of the plurality of power receiving coil elements 40a extends obliquely with respect to the tire radial direction.

[0101] As shown in FIGS. 9(A) to 9(H), the power receiving coil 40 may be formed of a plurality of power receiving coil elements 40a. On the inner surface of the tire cavity where the power receiving coil 40 is provided, during the rolling of the tire 10, the deformation and release of the tire 10 are repeated. When one power receiving coil 40 is provided around the entire circumference of the tire 10, this power receiving coil 40 has a portion that is deformed and distorted (near the grounding portion of the tire 10) and a portion that is not deformed (the upper portion of the tire 10) during the rolling of the tire 10, and the power receiving coil 40 is likely to peel off from the inner surface of the tire cavity. Therefore, by dividing the tire circumference into a plurality of regions and arranging the power receiving coil elements 40a in each of the divided regions, it is possible to suppress the peeling of the power receiving coil 40 from the inner peripheral surface of the tire.

[0102] FIG. 10 is a tire meridian cross-sectional view (however, half in the tire width direction) showing a power supply mode for supplying power from the power receiving coil 40 to the electronic device 46 attached to the inner surface of the tire cavity via the power line 44 in the tire 10B.

[0103] According to what is shown in the figure, the power receiving coil 40 is connected to a capacitor (not shown) as a resonant circuit, and further supplies power to an electronic device 46 (sensor, signal processing circuit, communication circuit, etc.) attached to the inner surface of the tire cavity via the power line 44 attached to the inner surface of the tire cavity. The electronic device 46 has lower durability against deformation than the power receiving coil 40, and on the other hand, even if it is installed near the belt 20 which is a magnetic body, there is no trouble due to the influence of the magnetic field. For this reason, the electronic device 46 is arranged on the inner surface of the tire cavity in the tire width direction region where the belt 20 having high rigidity is formed in the tire 10, the power receiving coil 40 is arranged on the inner surface of the tire cavity of the sidewall portion B where the power supply efficiency can be increased, and these two are wired-connected by the power line 44. Thereby, the power received by the power receiving coil 40 can be supplied to the electronic device 46 with less loss and high power supply efficiency, and at the same time, the durability of the electronic device 46 can be ensured. Further, by arranging all these components (power receiving coil 40, capacitor, power line 44, and electronic device 46) on the inner surface of the tire cavity, an increase in the manufacturing cost and manufacturing difficulty of the tire 10 is suppressed.

Example

[0104] Hereinafter, the comparison of the predetermined effects of the present application among the inventions defined in claims 1 to 6 of the present application (hereinafter referred to as "Invention Examples 1 to 9") will be described. Regarding the comparison between Invention Examples 1 to 9 and the conventional example (the example described in Patent Document 1), as described above, since the difference in the predetermined effects of the present application is obvious in terms of structure, it is not particularly mentioned together.

[0105] A tire having a tire size of 245 / 40R19 (specified by JATMA) was manufactured, as shown in FIG. 1. Regarding the various conditions of the tire 10 in Examples 1 to 10, they are as shown in Table 1 below.

[0106]

Table 1

[0107] In Table 1, regarding the anti-aging agent, wax, thickness of the outer rubber, deflection amount D, value calculated by formula (2), and height of unevenness, they conform to the definitions described in this specification.

[0108] Regarding the wireless power supply system using the tires of Invention Examples 1 to 9 manufactured in this way, the ratio (power transmission efficiency) of the power 2 received by the receiving coil (and the resonance circuit of the capacitor) to the power 1 transmitted from the transmission coil 52 was measured, and these ratios were expressed as indices when Invention Example 1 was set to 100. The measurement of the ratio of power 1 and 2 was performed using a vector network analyzer. The results are also shown in Table 1. Regarding the deposition amount and the presence or absence of cracks, all the tires were mounted on a regular rim, an air pressure of 230 kPa was applied, and they were mounted on the front wheels of a passenger car (FR sedan) with a vehicle weight of about 1800 kg and evaluated after traveling 2000 km. In Table 1, in the column of "deposition amount", based on the deposition amount of the anti-aging agent and wax in Invention Example 1, when the deposition amount is equal to or less than that of Invention Example 1, it is indicated as "A", and when the deposition amount is more than that of Invention Example 1, it is indicated as "B". In the column of "presence or absence of cracks", when there is no crack damage, it is indicated as "A", and when there is damage, it is indicated as "B".

[0109] According to Table 1, it can be seen that all the wireless power supply systems belonging to the technical scope of the present invention show excellent power transmission efficiency, and thus achieve excellent power supply efficiency.

Explanation of Signs

[0110] 10, 10A, 10B tires 12 inner liner 14 bead core 16 bead filler 18, 19 carcass 18a body part 18b folded-back part 19a, 19b carcass ply 20 belt 20a, 20b belt layer 22 belt cover 22a, 22b, 22c belt cover layer 24 rim cushion 25 second filler 26 side tread 27 run-flat liner 28 wing tip 30 cap tread 31 bead reinforcement layer 40 power receiving coil 41, 41a, 41b fixing member 42 wire 44 power line 46 electronic device 50 wireless power supply system 52 power transmission coil 54 wheel house A bead part B sidewall part C shoulder part D tread part Dp power supply direction G transmission gap O tire center R Tire circumferential direction range of 45° on both sides of the virtual line extending vertically upward from the tire center O Radial region of the power receiving coil R1 Region near the power receiving point R2 Power receiving region AR Thickness of the outer rubber t

Claims

1. A tire having a bead core, a bead filler provided on the outer side in the tire radial direction of the bead core, a carcass folded around the bead core, and a belt provided on the outer side in the tire radial direction of the carcass, the tire comprising a power receiving coil on the inner surface of the tire cavity for receiving power supplied by an alternating magnetic field from outside the tire, in a tire meridian cross-sectional view, the power receiving coil is provided in a tire radial direction region from the outermost position in the tire radial direction of the bead core to the innermost position in the tire radial direction of the belt, comprising an outer layer rubber exposed on the tire side surface of the tire radial direction region, the outer layer rubber contains 0.5 to 8.0 parts by mass of an anti-aging agent with respect to 100 parts by mass of the rubber and 0.1 to 5.0 parts by mass of wax with respect to 100 parts by mass of the rubber, a tire characterized by this.

2. The tire according to claim 1, wherein the thickness of the outer layer rubber is 2.5 to 20.0 mm.

3. In a tire mounted on a specified rim and applied with a normal internal pressure, the length SH in the tire radial direction from the bead toe to the tread surface of the tire in the unloaded state, and the amount of deflection D in the tire width direction before and after applying a load corresponding to 80% of the normal load to the tire, satisfy the following formula (1), the tire according to claim 1 or 2. 0.0278×SH−1.33≦D≦0.286×SH−13.7...(1)

4. The cross-sectional area S of the outer rubber ｏ and the 100% modulus M ｏ The sum of the products of and, The cross-sectional area S of the inner rubber layer disposed on the inner side in the tire width direction of the outer rubber layer and not exposed on the tire sidewall ｉ and the 100% modulus M ｉ The sum of the products thereof satisfies the following formula (2). The tire according to claim 1 or 2 【Number 1】

5. The tire according to claim 1 or 2, wherein the height of the unevenness on the surface of the outer layer rubber is 2.0 mm or less.

6. In a tire meridian cross-sectional view, a power receiving coil radial direction region defined by the length in the tire radial direction between both ends in the tire radial direction of the power receiving coil, and adjacent to both sides in the tire radial direction with respect to the power receiving coil radial direction region, and the length in the tire radial direction is defined by 15% of the length in the tire radial direction of the tire radial direction region in the vicinity of power reception region, the outer layer rubber contains 0.5 to 7.5 parts by mass of an anti-aging agent with respect to 100 parts by mass of the rubber and 0.1 to 4.5 parts by mass of wax with respect to 100 parts by mass of the rubber, the tire according to claim 1 or 2, wherein the height of the unevenness on the surface of the outer layer rubber is 1.5 mm or less.

7. A wireless power supply system that applies AC power to a power transmission coil that constitutes a resonance circuit with a capacitor and a coil, and transmits power to the power receiving coil that constitutes a resonance circuit with the capacitor and the coil, characterized by including the tire according to claim 1 or 2.

8. The wireless power supply system according to claim 7, wherein at least a part of the power receiving coil is located in a power supply region that extends in the winding axis direction of the power transmission coil between both longitudinal ends of the power transmission coil in a tire meridian cross-sectional view.

9. The wireless power supply system according to claim 7, wherein the power transmission coil is installed in a range of 60° on both sides in the tire circumferential direction centered on an imaginary line extending vertically upward from the tire center.

10. The wireless power supply system according to claim 7, wherein the power transmission coil is installed on a spring lower member of a vehicle.

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