JP2021095106A - Tire wheel assembly - Google Patents

Abstract

To provide a tire wheel assembly that can achieve high power receiving efficiency in automatic power supply using an electromagnetic induction system.SOLUTION: A tire wheel assembly includes a tire 10 and a wheel with a rim part. The tire is fitted to the rim part. The tire wheel assembly includes a power receiving coil. The tire includes: a pair of bead parts 11; and a carcass 14 including one or more carcass ply striding across the pair of bead parts toroidally. The carcass ply includes a cord inclined by an inclination angle of 80° or more relative to a tire circumferential direction.SELECTED DRAWING: Figure 2

Description

The present invention relates to a tire / wheel assembly.

In recent years, electric vehicles have been actively developed as vehicles that use electric energy as power (for example, Patent Document 1). In particular, in the autonomous driving technology that is being put into practical use in earnest, the development of the autonomous driving technology using an electric vehicle is proceeding because the response to the vehicle operation is better when the electric motor is used than when the engine is used. Has been done.

As a power supply system for supplying power to the power receiving device included in the tire / wheel assembly, an overhead wire system which is a wired system, an electromagnetic induction system which is a wireless system, an electric field coupling system, and the like have been proposed.

Japanese Unexamined Patent Publication No. 2018-088077

Among them, in the electromagnetic induction method, a current is passed through a transmission coil (primary coil) installed on the road surface side to generate a magnetic flux in a direction perpendicular to the road surface, and the magnetic flux is generated by the power receiving coil (primary coil) on the vehicle side. By passing through the secondary coil), a current flows through the power receiving coil, and electric energy is supplied from the power transmitting coil to the power receiving coil. The electromagnetic induction method is a technology that has attracted particular attention because of its high power receiving efficiency.

An object of the present invention is to provide a tire / wheel assembly capable of achieving high power receiving efficiency in automatic power feeding using an electromagnetic induction method.

The gist structure of the present invention is as follows.
(1) A tire and a wheel having a rim portion are provided.
The tire is attached to the rim portion and is mounted on the rim portion.
The tire / wheel assembly includes a power receiving coil.
The tire includes a pair of bead portions and a carcass composed of one or more carcass plies straddling the pair of bead portions in a toroidal shape.
The tire / wheel assembly is characterized in that the carcass ply cord is inclined at an inclination angle of 80 ° or more with respect to the tire circumferential direction.

The "rim" of the above "wheel" is an industrial standard that is effective in the area where tires are produced and used. In Japan, JATMA (Japan Automobile Tire Association) JATMA YEAR BOOK, and in Europe, ETRTO (The European). STANDARDS MANUAL of Tire and Rim Technical Organization), YEAR BOOK of TRA (The Tire and Rim Association, Inc.) in the United States, etc. In the case of "Measuring Rim", "Design Rim in YEAR BOOK of TRA" (that is, the "rim portion" of the above "wheel" includes a size that may be included in the above industrial standard in the future in addition to the current size. As an example of "size described in the future", the size described as "FUTURE DEVELOPMENTS" in the ETRTO 2013 edition can be mentioned.) If the size is not described in the above industrial standard, the tire A rim with a width corresponding to the bead width of.
Further, the "specified internal pressure" described later refers to the air pressure (maximum air pressure) corresponding to the maximum load capacity of a single wheel in the applicable size / ply rating described in the above JATMA, etc., and is not described in the above industrial standard. In the case of size, the "specified internal pressure" shall mean the air pressure (maximum air pressure) corresponding to the maximum load capacity specified for each vehicle equipped with tires.
Further, the "maximum load" described later means a load corresponding to the above maximum load capacity.

(2) In the above (1), a bead core is embedded in each of the pair of bead portions.
The carcass is composed of a carcass main body portion that straddles the pair of bead portions in a toroidal manner and a carcass winding portion that extends from the carcass main body portion and is wound from the inside to the outside in the tire width direction of the bead core. It is preferable to have one or more up plies.

According to the present invention, it is possible to provide a tire / wheel assembly capable of achieving high power receiving efficiency in automatic power feeding using an electromagnetic induction method.

It is the schematic which shows the wireless power receiving system which has the tire wheel assembly which concerns on one Embodiment of this invention by the cross section in the tire width direction. It is a tire width direction sectional view of the tire. It is sectional drawing in the width direction of a wheel. It is the schematic which shows the wireless power receiving system which has the tire wheel assembly of the modified example which concerns on one Embodiment of this invention by the cross section in the tire width direction. It is a schematic diagram which shows an example of a carcass structure. It is a tire width direction sectional view for demonstrating the depth of each gauge of a tire and the main groove in a circumferential direction. It is a top view which shows the structure of the inclined belt layer. It is a tire width direction sectional view of an example tire. It is a tire width direction sectional view of the tire of another example. It is a perspective view for demonstrating the structure of the reinforcing member of the example of FIG. It is a perspective view for demonstrating the structure of the reinforcing member of the example of FIG. It is sectional drawing which shows the inclined belt layer and the interlayer rubber. It is a tire width direction sectional view of an example tire. It is a tire width direction sectional view of an example tire. It is sectional drawing which shows an example of the end of the carcass folded part. It is sectional drawing which shows the other example of the end of a carcass folded part. It is sectional drawing which shows another example of the end of a carcass folded part. It is sectional drawing which shows the example in which the side reinforcing rubber is arranged. It is sectional drawing which shows another example in which the side reinforcing rubber is arranged. It is a tire width direction sectional view of an example tire. It is a tire width direction sectional view of an example tire.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, unless otherwise specified, the dimensions and the like refer to the dimensions and the like in the above standard state.

<Wireless power receiving system>
FIG. 1 is a schematic view schematically showing a wireless power receiving system having a tire / wheel assembly according to an embodiment of the present invention with a cross section in the tire width direction. The wireless power receiving system 1 is a system configured to receive electric power transmitted wirelessly (that is, wirelessly) from an external power transmission device. Explaining the external configuration of the wireless power receiving system first, the power transmission device 40 includes a power transmission coil (primary coil) 41. The power transmission device 40 is installed on a road surface such as a road, or is buried so as to be located near the road surface. The power transmission coil 41 generates an alternating magnetic field based on the alternating current supplied from the power source. The power transmission coil 41 is formed in an annular shape as a whole, and is arranged so that the axial direction of the ring is substantially perpendicular to the road surface so as to generate an alternating magnetic field toward the upper side of the road surface. However, in the drawing, the power transmission coil 41 is modeled. The power transmission coil 41 included in the power transmission device 40 is wound around a core such as a ferrite core and has an annular structure as a whole. It can be any coil that can be generated.
As shown in FIG. 1, the wireless power receiving system 1 includes a tire / wheel assembly 3 according to an embodiment of the present invention. The power receiving device 30 that receives the electric power supplied by radio is housed in the accommodating portion of the tire / wheel assembly 3 (the accommodating portion is a space inside the tire / wheel assembly 3). Hereinafter, the tire / wheel assembly 3 will be described.

≪Tire / Wheel Assembly≫
As shown in FIG. 1, the tire / wheel assembly 3 according to the embodiment of the present invention includes a tire 10 and a wheel 20 having a rim portion 21. The tire 10 is attached to the rim portion 21 of the wheel 20. Hereinafter, the tire 10 and the wheel 20 will be described in order.

(tire)
First, the configuration of an example of the tire 10 will be described. FIG. 2 is a cross-sectional view of the tire 10 in the tire width direction. As shown in FIG. 2, the tire 10 has a pair of bead portions 11, a pair of sidewall portions 12 connected to the bead portions 11, and a tread portion 13 connected to the pair of sidewall portions 12. ing.

In this example, the bead portion 11 has a bead core 11A and a bead filler 11B. The bead core 11A includes a plurality of bead wires around which the bead core 11A is covered with rubber in this example. The bead wire is formed by a steel cord in this example. The bead filler 11B is made of rubber or the like and is located outside the bead core 11A in the tire radial direction. In this example, the bead filler 11B has a substantially triangular cross section in which the thickness decreases toward the outside in the radial direction of the tire. On the other hand, in the present invention, the tire 10 may have a structure that does not have the bead core 11A or the bead filler 11B.

In the present invention, the bead wire can also be formed of a non-magnetic material. This is because the bead wire is made of a non-magnetic material so that the magnetic field reaching the power receiving coil 31 from the power transmitting coil 41 is not obstructed by the bead wire. Here, the non-magnetic material refers to a material other than the magnetic material, and the magnetic material refers to a material exhibiting ferromagnetism (ferromagnet). Therefore, the non-magnetic material includes a paramagnetic material and a diamagnetic material having a small magnetic permeability. As the non-magnetic material, for example, a resin material containing a thermoplastic resin such as polyester and nylon, a thermosetting resin such as a vinyl ester resin and an unsaturated polyester resin, and other synthetic resins can be used. The resin material can further contain fibers such as glass, carbon, graphite, aramid, polyethylene, and ceramic as reinforcing fibers. As the non-magnetic material, not only resin but also any non-metal material including rubber, glass, carbon, graphite, aramid, polyethylene, ceramic and the like can be used. Further, as the non-magnetic material, a metal material containing a paramagnetic material such as aluminum or a diamagnetic material such as copper can be used.

As shown in FIG. 2, the tire 10 has a carcass 14 straddling a pair of bead portions 11 in a toroidal manner. The end side of the carcass 14 is locked to the bead core 11A. Specifically, the carcass 14 has a carcass main body portion 14A arranged between the bead cores 11A and a carcass folding portion 14B that is folded around the bead core 11A from the inside in the tire width direction to the outside in the tire width direction. ing. The extending length of the carcass folded-back portion 14B from the inside in the tire width direction to the outside in the tire width direction can be appropriately set. Further, the carcass 14 may have a structure that does not have the carcass folded-back portion 14B, or may have a structure in which the carcass folded-back portion 14B is wound around the bead core 11A.

The carcass 14 can be composed of one or more carcass plies. For example, the carcass 14 can be composed of two carcass layers arranged so as to be laminated in the tire radial direction on the equatorial plane CL of the tire. In the present embodiment, the carcass cord constituting the carcass layer of the carcass 14 is made of a non-magnetic material (organic fiber in this example). Alternatively, the carcass cord constituting the carcass 14 can be configured with a steel cord.
Non-magnetic materials include paramagnetic and diamagnetic materials with low magnetic permeability. As the non-magnetic material, for example, a resin material containing a thermoplastic resin such as polyester and nylon, a thermosetting resin such as a vinyl ester resin and an unsaturated polyester resin, and other synthetic resins can be used. The resin material can further contain fibers such as glass, carbon, graphite, aramid, polyethylene, and ceramic as reinforcing fibers. As the non-magnetic material, not only resin but also any non-metal material including rubber, glass, carbon, graphite, aramid, polyethylene, ceramic and the like can be used. Further, as the non-magnetic material, a metal material containing a paramagnetic material such as aluminum or a diamagnetic material such as copper can be used.
In the present invention, a steel cord can be used as the carcass cord, but it is preferable to use a carcass cord made of a non-magnetic material. This is because the magnetic field reaching the power receiving coil 31 from the power transmitting coil 41 can be prevented from being obstructed by the carcass 14, and thus the power receiving efficiency can be improved.

A belt 15 and tread rubber are provided on the outer side of the crown portion of the carcass 14 in the tire radial direction. The belt 15 can be composed of, for example, one or more belt layers. In the illustrated example, the belt layer 15B is arranged on the outer side of the belt layer 15A in the tire radial direction. In the present embodiment, the belt cord forming the belt layer of the belt 15 is made of a non-magnetic material (organic fiber in this example). Alternatively, a steel cord can be used as the belt cord constituting the belt 15.
Non-magnetic materials include paramagnetic and diamagnetic materials with low magnetic permeability. As the non-magnetic material, for example, a resin material containing a thermoplastic resin such as polyester and nylon, a thermosetting resin such as a vinyl ester resin and an unsaturated polyester resin, and other synthetic resins can be used. The resin material can further contain fibers such as glass, carbon, graphite, aramid, polyethylene, and ceramic as reinforcing fibers. As the non-magnetic material, not only resin but also any non-metal material including rubber, glass, carbon, graphite, aramid, polyethylene, ceramic and the like can be used. Further, as the non-magnetic material, a metal material containing a paramagnetic material such as aluminum or a diamagnetic material such as copper can be used.
In the present invention, a steel cord can be used as the belt cord constituting the belt 15, but it is preferable to use a belt cord made of a non-magnetic material. This is because the magnetic field reaching the power receiving coil 31 from the power transmitting coil 41 can be prevented from being obstructed by the belt 15, and thus the power receiving efficiency can be improved. In the present invention, the number of layers of the belt layer, the inclination angle of the belt cord, the width of each belt layer in the tire width direction, and the like are not particularly limited and can be appropriately set.

As shown in FIG. 2, the tire 10 has an inner liner 16. The inner liner 16 is arranged so as to cover the inner surface of the tire 10. The inner liner 16 can be composed of one or more inner liner layers laminated in the tire radial direction on the equatorial surface CL of the tire. The inner liner 16 is made of, for example, a butyl rubber having low air permeability. Butyl rubber includes, for example, butyl rubber and a halogenated butyl rubber which is a derivative thereof. The inner liner 16 is not limited to the butyl rubber, and may be composed of other rubber compositions, resins, or elastomers.

In the present invention, the sidewall portion 12 may have a side reinforcing rubber. The side reinforcing rubber may have a crescent-shaped cross section, for example. As a result, when the tire is punctured, the side reinforcing rubber can take over the load and run.

The tire is preferably a passenger car tire, and more preferably a passenger car radial tire.

Here, in the tire 10, when the cross-sectional width SW of the tire 10 is less than 165 (mm), the ratio SW / OD of the cross-sectional width SW of the tire 10 and the outer diameter OD is 0.26 or less, and the tire. When the cross-sectional width SW of 10 is 165 (mm) or more, the cross-sectional width SW (mm) and the outer diameter OD (mm) of the tire 10 are determined.
OD (mm) ≥ 2.135 x SW (mm) + 282.3 (mm)
(Hereinafter referred to as "relational expression (1)")
It is preferable to satisfy.
By satisfying the above ratio SW / OD or the relational expression (1), the cross-sectional width SW of the tire 10 becomes relatively small with respect to the outer diameter OD of the tire 10, the air resistance is reduced, and the cross-sectional width is narrow. Therefore, it is possible to secure a vehicle space, and in particular, it is possible to secure an installation space for drive parts near the inside of the tire mounted on the vehicle.
Further, by satisfying the ratio SW / OD or the relational expression (1), the outer diameter OD of the tire 10 becomes relatively large with respect to the cross-sectional width SW of the tire 10, the rolling resistance is reduced, and the tire 10 is further satisfied. As the diameter of the tire increases, the wheel shaft becomes taller and the space under the floor is expanded, so that it is possible to secure a space for a vehicle trunk and the like and a space for installing drive parts.
As described above, by satisfying the above ratio SW / OD or the relational expression (1), it is possible to achieve low fuel consumption with respect to the supplied electric energy, and it is also possible to secure a large vehicle space. ..
Further, the tire 10 has a cross-sectional width SW (mm) and an outer diameter OD (mm) of the tire 10.
OD (mm) ≥ -0.0187 x SW (mm) ² + 9.15 x SW (mm) -380 (mm)
(Hereinafter referred to as "relational expression (2)")
It is preferable to satisfy.
By satisfying the above relational expression (2), the cross-sectional width SW of the tire becomes relatively small with respect to the outer diameter OD of the tire 10, the air resistance is reduced, and the vehicle space is secured due to the narrow cross-sectional width. In particular, it is possible to secure an installation space for drive parts in the vicinity of the inside of the tire 10 mounted on the vehicle.
Further, by satisfying the above relational expression (2), the outer diameter OD of the tire becomes relatively large with respect to the cross-sectional width SW of the tire 10, the rolling resistance is reduced, and the wheel is increased by increasing the diameter of the tire 10. Since the shaft is raised and the space under the floor is expanded, it is possible to secure a space such as a trunk of a vehicle and a space for installing drive parts.
As described above, by satisfying the above relational expression (2), it is possible to achieve low fuel consumption with respect to the supplied electric energy, and it is also possible to secure a large vehicle space.
In each of the above examples, the tire 10 preferably satisfies the ratio SW / OD and / or the relational expression (2), or preferably satisfies the relational expression (1) and / or the relational expression (2). ..

Further, it is preferable that the tire width direction cross-sectional area S1 of the bead filler 11B is 1 time or more and 8 times or less of the tire width direction cross-sectional area S2 of the bead core 11A. As a result, both power supply efficiency and fuel efficiency can be suitably achieved.
In the case of a sandwiched bead core structure in which the carcass is held from the inside and the outside in the width direction of the tire, the total volume of the bead cores inside and outside the width direction of the carcass is defined as S2.
By setting the cross-sectional area S1 of the bead filler 11B to the above range, the volume of the bead filler, which is a high-rigidity member, can be reduced, the vertical spring constant of the tire can be reduced, and the riding comfort can be improved. It is also possible to reduce the weight of the bead filler and reduce the weight of the tire, and therefore the rolling resistance value of the tire is further reduced.
In particular, in a narrow-width / large-diameter tire that satisfies the above relational expression (1) or (2), the tension rigidity of the belt is high and the tension rigidity of the tire side portion is lower than that of the belt. In addition, the effect of reducing the vertical spring constant by setting the cross-sectional area S1 of the bead filler within a predetermined range becomes very high.
Here, the cross-sectional area S1 in the tire width direction of the bead filler 11B is set to 8 times or less the cross-sectional area S2 in the tire width direction of the bead core 11A so that the volume of the bead filler, which is a high-rigidity member, does not become too large. By preventing the vertical spring constant from becoming too large, it is possible to suppress a decrease in ride comfort.
On the other hand, by setting the tire width direction cross-sectional area S1 of the bead filler 11B to one or more times the tire width direction cross-sectional area S2 of the bead core 11A, the rigidity of the bead portion is ensured and the lateral spring coefficient does not decrease too much. In this way, steering stability can be ensured.

Here, in the tire 10, when the width in the tire width direction of the bead filler 11B at the center position in the tire radial direction is BFW and the maximum width of the bead core 11A in the tire width direction is BDW,
0.1 ≤ BFW / BDW ≤ 0.6
It is preferable to satisfy.
As a result, both power supply efficiency and fuel efficiency can be suitably achieved.
By setting the ratio BFW / BDW to 0.6 or less, the volume of the bead filler is reduced while maintaining the height of the bead filler, the rigidity in the tire rotation direction is secured, and the vertical spring constant is reduced for riding. The comfort can be improved and the weight of the tire can be reduced.
On the other hand, by setting the ratio BFW / BDW to 0.1 or more, the rigidity of the bead portion can be ensured, the lateral spring constant can be maintained, and the steering stability can be further ensured.

Here, in the tire 10, when the height of the bead filler 11B in the tire radial direction is BFH and the section height (tire cross-sectional height) of the tire is SH,
0.1 ≤ BFH / SH ≤ 0.5
It is preferable to satisfy.
As a result, both power supply efficiency and fuel efficiency can be suitably achieved.
By setting the ratio BFH / SH to 0.5 or less, the radial height of the bead filler, which is a high-rigidity member, is reduced, the vertical spring constant of the tire is effectively reduced, and the riding comfort is improved. Can be done.
On the other hand, by setting the ratio BFH / SH to 0.1 or more, the rigidity of the bead portion can be ensured, the lateral spring constant can be maintained, and the steering stability can be further ensured.
Here, the tire section height SH is 1 / of the difference between the outer diameter of the tire and the rim diameter in the no-load state when the tire is incorporated in the rim and the internal pressure specified for each vehicle to which the tire is mounted is applied. It shall refer to 2.

The height BFH of the bead filler 11B in the tire radial direction is preferably 45 mm or less. As a result, both power supply efficiency and fuel efficiency can be suitably achieved.

In each of the above examples, the tire 10 has a gauge Ts of the sidewall portion 12 at the tire maximum width position (measured in this cross section in the normal direction of the tangent line at a point on the tire surface at the tire maximum width position) and a bead core. It is preferable that the ratio Ts / Tb with the bead width Tb (the width of the bead portion 11 in the tire width direction) at the center position in the tire radial direction of 11A is 15% or more and 60% or less. As a result, both power supply efficiency and fuel efficiency can be suitably achieved.
The "maximum tire width position" means the maximum width position in the cross section in the tire width direction in the reference state.
Gauge Ts is the total thickness of all members such as rubber, reinforcing members, and inner liner.
By setting the ratio Ts / Tb to the above range, it is possible to appropriately reduce the rigidity at the maximum width position of the tire where the bending deformation is large when the tire is loaded, reduce the vertical spring constant, and improve the riding comfort. ..
That is, if the ratio Ts / Tb exceeds 60%, the gauge of the sidewall portion 12 at the maximum tire width position becomes large, the rigidity of the sidewall portion 12 becomes high, and the vertical spring coefficient may become high. is there. On the other hand, if the ratio Ts / Tb is less than 15%, the lateral spring constant may be too low to ensure steering stability.

In each of the above examples, the tire 10 preferably has a gauge Ts of the sidewall portion 12 at the maximum tire width position of 1.5 mm or more. As a result, both power supply efficiency and fuel efficiency can be suitably achieved.
By setting the gauge Ts to 1.5 mm or more, it is possible to maintain an appropriate rigidity at the maximum tire width position, suppress a decrease in the lateral spring coefficient, and further secure steering stability.

In each of the above examples, the tire 10 preferably has a bead core 11A having a diameter Tbc (maximum width of the bead core in the tire width direction) of 3 mm or more and 16 mm or less. As a result, both power supply efficiency and fuel efficiency can be suitably achieved.
By setting Tbc to 3 mm or more, it is possible to realize weight reduction while ensuring bending rigidity and torsional rigidity on the rim flange, while by setting Tbc to 16 mm or less, weight increase can be suppressed. , Steering stability can be ensured.
Further, in the case of a structure in which the bead core is divided into a plurality of small bead cores by a carcass, the distance between the innermost end portion and the outermost outermost end portion in the width direction of all the small bead cores may be Tbc.

^{In each of the above examples, the tire 10 preferably has a ground contact area of 8000 mm 2} or more when a maximum load specified for each vehicle to which the tire is mounted is applied. As a result, it is possible to achieve both a reduction in the rolling resistance value of the tire and a reduction in the weight of the tire, and it is possible to preferably achieve both the power supply efficiency and the low fuel consumption. In addition, the tire axial force can be secured to improve the stability and safety of the vehicle.

In each of the above examples, the tire 10 preferably has a belt cord Young's modulus of 40,000 MPa or more. As a result, the carcass structure and belt rigidity can be optimized, and the strength of the tire that can be used even at a high internal pressure can be ensured. In addition, power supply efficiency and fuel efficiency can be suitably compatible with each other.

In each of the above examples, the tire 10 preferably has an inner liner 16 having a thickness of 0.6 mm or more. This makes it possible to suppress air leakage in a high internal pressure state. In addition, power supply efficiency and fuel efficiency can be suitably compatible with each other.

In each of the above examples, it is preferable that the ratio Ts / Tc of the gauge Ts of the sidewall portion 12 and the diameter Tc of the carcass cord at the tire maximum width position is 4 or more and 12 or less. As a result, both power supply efficiency and fuel efficiency can be suitably achieved.
By setting the ratio Ts / Tc to the above range, it is possible to appropriately reduce the rigidity at the maximum width position of the tire where the bending deformation is large when the tire is loaded, reduce the vertical spring constant, and improve the riding comfort. ..
That is, by setting the ratio Ts / Tc to 12 or less, the gauge of the sidewall portion 4 at the maximum tire width position is prevented from becoming too large, the rigidity of this portion is increased, and the longitudinal spring coefficient is increased. Can be suppressed. On the other hand, by setting the ratio Ts / Tc to 4 or more, the lateral spring constant can be prevented from being lowered too much, and steering stability can be ensured.

In each of the above examples, the tire 10 has a ratio Ta / Tc of the distance Ta and the diameter Tc of the carcass cord, where Ta is the distance in the tire width direction from the surface of the carcass cord to the outer surface of the tire at the maximum width position of the tire. Is preferably 2 or more and 8 or less. As a result, both power supply efficiency and fuel efficiency can be suitably achieved.
By setting the ratio Ta / Tc to 8 or less, the gauge of the sidewall portion 12 at the maximum tire width position is reduced, the rigidity of the sidewall portion 12 is reduced, the vertical spring coefficient is reduced, and the riding comfort is reduced. Can be further improved. On the other hand, by setting the ratio Ta / Tc to 2 or more, the lateral spring constant can be secured and the steering stability can be further ensured.
In addition, "Ta" means the distance in the tire width direction from the surface of the outermost carcass cord in the width direction to the outer surface of the tire at the tire maximum width position.
That is, when the carcass folded-back portion 14B extends radially outward from the maximum tire width position, the distance in the tire width direction from the surface of the carcass cord 14c of the portion forming the carcass folded-back portion 14B to the outer surface of the tire is set as Ta. ..

In each of the above examples, the tire 10 preferably has a carcass cord 14c having a diameter Tc of 0.2 mm or more and 1.2 mm or less. As a result, both power supply efficiency and fuel efficiency can be suitably achieved.
By setting the Tc to 0.8 mm or less, the vertical spring coefficient can be reduced and the ride quality can be improved. On the other hand, by setting the Tc to 0.4 mm or more, the lateral spring coefficient can be increased for maneuvering. Stability can be ensured.

Here, the internal pressure of the tire / wheel assembly is preferably 120 to 200 kPa. By setting the internal pressure to 200 kPa or less, the ground contact area becomes large. When the ground contact area is small, a space is created between the tire and the road surface, and water, foreign matter, etc. enter between them to hinder the magnetic flux and reduce the power receiving efficiency. It is possible to improve the power receiving efficiency by eliminating the space between the road surface and preventing the magnetic flux from being hindered by water, foreign matter, or the like. Further, by setting the internal pressure to 200 kPa or less, the sidewall portion of the tire is easily bent, and the distance between the power receiving coil and the power transmission coil can be shortened, which also improves the power receiving efficiency. Further, according to the tire / wheel assembly of the present embodiment, the internal pressure is 120 kPa or more, and rolling resistance can be reduced to improve fuel efficiency.
Here, the internal pressure is more preferably 140 to 180 kPa. This is because the power receiving efficiency can be further improved while further improving the fuel efficiency.
Further, the internal pressure is more preferably 150 to 170 kPa. This is because the power receiving efficiency can be further improved while further improving the fuel efficiency.
It is preferable that the relational expressions (1) and / or (2) of SW and OD are satisfied when the above internal pressure is applied.

Alternatively, the internal pressure of the tire / wheel assembly is preferably more than 200 kPa and 400 kPa or less. By setting the internal pressure to more than 200 kPa, rolling resistance can be reduced and fuel efficiency can be improved. Further, by setting the internal pressure to 400 kPa or less, the ground contact area becomes large. When the ground contact area is small, a space is created between the tire and the road surface, and water, foreign matter, etc. enter between them to hinder the magnetic flux and reduce the power receiving efficiency. It is possible to improve the power receiving efficiency by eliminating the space between the road surface and preventing the magnetic flux from being hindered by water, foreign matter, or the like. Further, by setting the internal pressure to 400 kPa or less, the sidewall portion of the tire is easily bent, and the distance between the power receiving coil and the power transmission coil can be shortened, which also improves the power receiving efficiency.
Here, the internal pressure is more preferably 260 to 350 kPa. It is possible to further improve fuel efficiency while further improving power receiving efficiency. Further, the internal pressure is more preferably 300 to 320 kPa. It is possible to further improve fuel efficiency while further improving power receiving efficiency.
It is preferable that the relational expressions (1) and / or (2) of SW and OD are satisfied when the above internal pressure is applied.

(wheel)
Next, the configuration of the wheel 20 will be described. FIG. 3 is a cross-sectional view in the width direction of the wheel 20 according to the embodiment of the present invention.

As shown in FIG. 3, the wheel 20 has a cylindrical rim portion 21 and a disc portion 22 provided inside the rim portion 21 in the radial direction and supported and fixed to the hub 2A of the vehicle 2. ..

The rim portion 21 has a pair of flanges 23 (inner flange 23A, outer flange 23B), a pair of bead seats 24 (inner bead seat 24A, outer bead seat 24B), and wells 25 from the outside in the width direction of the wheel. I have. The bead portion 11 of the tire 10 is mounted on the bead seat 24. The flange 23 extends from the bead seat 24 outward in the radial direction of the wheel and outward in the width direction of the wheel in order to support the bead portion 11 of the tire 10 from the side surface. The well 25 has a concave shape inward in the radial direction between the pair of bead seats 24 in order to facilitate the attachment / detachment of the tire. The well 25 has a bottom and an inclined surface connecting the bottom and the bead sheet 24. Further, the bead seat 24 is provided with a pair of humps 26 (inner hump 26A, outer hump 26B) inside the width direction of the wheel. The hump 26 projects radially outward of the wheel to prevent the tire bead from falling into the well 25.

The rim portion 21 can be made of, for example, a non-magnetic material.
Non-magnetic materials include paramagnetic and diamagnetic materials with low magnetic permeability. As the non-magnetic material, for example, a resin material containing a thermoplastic resin such as polyester and nylon, a thermosetting resin such as a vinyl ester resin and an unsaturated polyester resin, and other synthetic resins can be used. The resin material can further contain fibers such as glass, carbon, graphite, aramid, polyethylene, and ceramic as reinforcing fibers. As the non-magnetic material, not only resin but also any non-metal material including rubber, glass, carbon, graphite, aramid, polyethylene, ceramic and the like can be used. Further, as the non-magnetic material, a metal material containing a paramagnetic material such as aluminum or a diamagnetic material such as copper can be used. As a result, the magnetic field reaching the power receiving coil 31 from the power transmitting coil 41 can be prevented from being obstructed by the rim portion 21, and the power receiving efficiency can be improved.

Further, the rim portion 21 of the wheel 20 is provided with a valve 27 for filling the lumen of the tire 10 with a gas such as air when the tire 10 is mounted. The valve 27 can be made of, for example, the resin material described above. By configuring the valve 27 with the non-magnetic material described above, it is possible to prevent the magnetic field reaching the power receiving coil 31 from the power transmitting coil 41 from being obstructed by the valve 27.

The disk portion 22 has an annular mounting portion 22A constituting its radial inner end portion, and a plurality of spokes 22B extending radially outward from the mounting portion 22A. The mounting portion 22A is a portion to be coupled and fixed to the hub 2A of the vehicle 2 (see FIGS. 1 and 3), and is in the width direction of the wheel in order to insert a bolt or the like for fixing the hub 2A and the mounting portion 22A. It has a mounting hole that penetrates. The radial outer end of the wheel of the spokes 22B is integrally coupled to the end of the wheel radial inner surface of the rim portion 21.

The disk portion 22 may include, for example, a magnetic material having a high magnetic permeability (for example, a ferromagnetic material) such as metal or ferrite. As a result, the magnetic field reaching the power receiving coil 31 from the power transmitting coil 41 can be made less likely to be attenuated by the influence of the metal and other magnetic fields existing outside the tire / wheel assembly 3, and the power receiving efficiency can be improved. Can be done. For example, when the disc portion 22 is made of a resin material, the weight of the wheel 20 can be reduced.

The disc portion 22 of the wheel 20 further includes a wheel cover 28 that covers the outside of the spoke 22B in the width direction. The wheel cover 28 may include, for example, a magnetic material having a high magnetic permeability (for example, a ferromagnetic material) such as metal or ferrite. As a result, the magnetic field reaching the power receiving coil 31 from the power transmitting coil 41 can be made less likely to be attenuated by the influence of the metal and other magnetic fields existing outside the tire / wheel assembly 3, and the power receiving efficiency can be improved. Can be done.

The wheel 20 receives power supplied wirelessly from the tire radial outside of the tire 10 to the inside of the rim portion 21 in the tire radial direction, that is, in the space surrounded by the rim portion 21 and the disc portion 22. It is provided with a storage unit for accommodating (see FIGS. 1 and 4). For example, when the power receiving device 30 is attached to the hub 2A of the vehicle 2, the power receiving device 30 is accommodated in the accommodating portion of the wheel 20 by attaching the wheel 20 to the hub 2A of the vehicle 2.

<Power receiving coil>
Returning to FIG. 1, the power receiving device 30 is attached to, for example, the hub 2A of the vehicle 2, but the power receiving device 30 is not limited to this, and the power receiving device 30 is attached to the hub 2A of the vehicle 2 such as the drive shaft 2B. 30 can be attached to any position where the wheel 20 is housed inside the rim portion 21 of the wheel 20 in the tire radial direction. In this example, the power receiving device 30 is configured to be non-rotating with respect to the rotation of the tire 10 and the wheel 20.
In the present embodiment, the power receiving coil (secondary coil) 31 is attached to the outer peripheral surface of the bottom of the well 25, and four power receiving coils 31 are arranged on the circumference at equal intervals (interval d (mm)). ing. Therefore, in this example, the power receiving coil 31 is configured to rotate together with the rotation of the tire 10 and the wheel 20. At this time, the position of the power receiving coil 31 on the circumference changes with the rotation of the tire 10 and the wheel 20, but the power receiving coil 31 is in a state where the tire / wheel assembly 3 is located above the power transmission device 40. At least at a certain tire rotation angle, the tires are arranged so as to face the transmission coil 41. As a result, when the tire 10 is located on the road surface above the power transmission coil 41 and the power transmission coil 41 and the power reception coil 31 face each other, an electromotive force is generated in the power reception coil 31 based on the alternating magnetic field generated by the power transmission coil 41. It is generated, current flows and power is supplied. The power receiving coil 31 is formed in an annular shape as a whole, and is arranged so that the axial direction of the ring is substantially perpendicular to the road surface. The power receiving coil 31 is wound around a core such as a ferrite core to form an annular shape as a whole, but is not limited to this, and an electromotive force is generated based on an alternating magnetic field such as a coil spring or an air core coil. It can be any coil that can be generated.
Here, the power receiving coil 31 may be attached to the inner peripheral surface of the bottom of the well 25 as long as it can face the power transmission coil 41 when the tire 10 is located on the road surface above the power transmission coil 41. Alternatively, it can be attached to the inner peripheral surface or the outer peripheral surface of another portion of the rim portion 21. In this case as well, the power receiving coil 31 rotates with the rotation of the tire 10 and the wheel 20. Alternatively, it can be mounted inside the tire / wheel assembly 3. In this case, the power receiving coil 31 may be configured to be non-rotating with respect to the rotation of the tire 10 or the wheel 20, or for example, a core protruding into the tire cavity fixed to the wheel 20 may be provided. Therefore, the power receiving coil 31 can be attached to the core so that the power receiving coil 31 rotates with the rotation of the tire 10 and the wheel 20.
The number of power receiving coils 31 is not particularly limited. For example, when a continuous power receiving coil 31 is used on one circumference, the tire 10 is located on the road surface above the power transmission coil 41. In addition, continuous power supply is possible during the rolling of the tire, or if the total size of the power receiving coil 31 is reduced by dividing the tire into a plurality of parts, the weight increase due to the power receiving coil 31 can be suppressed and the fuel consumption can be reduced. The sex can be improved. In the present embodiment, four power receiving devices 30 are included corresponding to the above four power receiving coils 31, but the number of power receiving devices 30 is also an arbitrary number according to the number of power receiving coils 31 and the like. The number of power receiving devices 30 can be different from the number of power receiving coils 31.

In this example, the power receiving device 30 includes a power conversion circuit 32, a power storage unit 33, and a control unit 34. The power conversion circuit 32 converts the power generated in the power receiving coil 31 into DC power, and supplies the DC power to the power storage unit 33 or another in-vehicle device included in the vehicle 2 via a conductive wire or the like. The power storage unit 33 stores the electric power generated in the power receiving coil 31. The power storage unit 33 is, for example, a capacitor, but is not limited to this, and can be any power storage device such as a storage battery. When the power storage unit 33 is a capacitor, charging / discharging can be performed in a shorter time than that of a storage battery. Therefore, the power storage unit 33, which is a capacitor, is advantageous in a situation where high responsiveness is required such that the power generated in the power receiving coil 31 is stored when the vehicle 2 travels on the power transmission device 40 provided on the road. Is. The control unit 34 may include one or more processors that provide processing for controlling each function of the power receiving device 30. The control unit 34 can be a general-purpose processor such as a CPU (Central Processing Unit) that executes a program that defines a control procedure, or a dedicated processor that specializes in processing each function. The control unit 34 can include a storage means for storing a program or the like, and an arbitrary means used for controlling a power receiving device 30 such as a communication means for communicating with an external electronic device by wire or wirelessly.
When the power receiving coil 31 is configured to rotate with the rotation of the tire 10 and the wheel 20, as in the present embodiment, the electric power generated in the power receiving coil 31 is transmitted to the power receiving coil 31 via, for example, a slip ring. It can be transmitted to the power conversion circuit 32 or the like. Alternatively, the power generated in the power receiving coil 31 is transmitted to the first relay coil (by wire), and the magnetic field generated by the current flowing through the first relay coil passes through the second relay coil to the second relay coil. A current flows and can be transmitted from the second relay coil to the power conversion circuit 32 or the like. In this case, the first relay coil and the second relay coil are also configured to rotate with the rotation of the tire 10 and the wheel 20, and in the case of the above example, the relay coil can be attached to the outer peripheral surface of the well 25 as an example. ..
On the other hand, when the power receiving coil 31 does not rotate with respect to the rotation of the tire 10 or the wheel 20 (for example, when the power receiving coil 31 is attached to the hub 2A), the power storage unit 33 directly from the power receiving coil 31. Etc. can be transmitted. In this case, in particular, the carcass 14 is made of the above-mentioned non-magnetic material, the belt cord is made of the above-mentioned non-magnetic material, and the rim portion 21 of the wheel 20 is made of the above-mentioned non-magnetic material, thereby suppressing the decrease in power receiving efficiency. It is preferable from the viewpoint of

FIG. 4 is a schematic view schematically showing a wireless power receiving system having a tire / wheel assembly of a modified example according to an embodiment of the present invention by a cross section in the tire width direction.
In the example shown in FIG. 4, the tire / wheel assembly 1 includes an in-wheel motor 4. A power receiving device 30 is attached to the in-wheel motor 4.
As shown in FIG. 4, the power receiving device 30 can be attached to the tire 10 or the wheel 20 so that the tire 10 or the wheel 20 does not rotate when the tire 10 or the wheel 20 rotates (in the illustrated example, the cover of the hub 2A or the like).
In this case, in particular, only one power receiving device 30 (power receiving coil 31) can be arranged at a position facing the road surface. On the other hand, as shown in FIG. 1, when the power receiving device 30 is mounted at a position where the tire 10 and the wheel 20 rotate with rotation, one or more power receiving devices 30 (power receiving coil 31) are installed. , It is preferable to install the wheel 20 continuously or intermittently in the circumferential direction.

Returning to the description of the tire, in the present embodiment, the tire 10 includes a carcass 14 composed of one or more carcass plies, and the carcass ply cord has an inclination angle of 80 ° or more with respect to the tire circumferential direction. It is tilted.
Hereinafter, the action and effect of the tire / wheel assembly of the present embodiment will be described.

According to the tire / wheel assembly of the present embodiment, the cord of the carcass ply is inclined at an inclination angle of 80 ° or more with respect to the tire circumferential direction. This reduces tire deflection when a load is applied to the tire / wheel assembly (compared to the case where the carcass ply cord is tilted at an inclination angle of less than 80 ° with respect to the tire circumferential direction). This makes it possible to suppress fluctuations in the distance between the power transmission coil and the power reception coil and improve the power reception efficiency.

From the viewpoint of reducing the bending of the tire under load and improving the power receiving efficiency, the carcass ply cord is more preferably inclined at an inclination angle of 85 ° or more with respect to the tire circumferential direction, and is 90 °. It is more preferable that the tire is tilted at the tilt angle of.

From the viewpoint of reducing the bending of the tire under load and improving the power receiving efficiency, the number of carcass plies is preferably a plurality, and may be, for example, two or three. On the other hand, from the viewpoint of suppressing the weight increase due to the carcass, the number of carcass plies is preferably one.

FIG. 5 is a schematic view showing an example of the carcass structure.
As shown in FIG. 5, the carcass is composed of a carcass main body portion that straddles a pair of bead portions in a toroidal shape and a carcass winding portion that extends from the carcus main body portion and is wound up from the inside to the outside in the tire width direction of the bead core. It is also preferable to have one or more (two in the example shown in FIG. 5) up ply including the winding portion. By such a combination, it is possible to achieve a good balance between suppressing the weight increase due to the carcass and improving the power receiving efficiency. The bead core has an inner bead core on the inner side in the tire width direction and an outer bead core on the outer side in the tire width direction, and the carcass may be interposed between the inner bead core and the outer bead core.
As for the end of the upply, as shown in the figure, the end of the upply whose winding part is located inside in the tire width direction is located outside the end of the upply where the winding part is located outside in the tire width direction. However, it may be inside the tire radial direction or at the same position.

FIG. 6 is a cross-sectional view in the tire width direction for explaining the depth of each gauge and the main groove in the circumferential direction of the tire. FIG. 6 shows only one half in the tire width direction with the tire equatorial plane CL as the boundary, and the other half in the tire width direction has the same gauge (symmetrical with the tire equatorial plane CL as the boundary). Can be). However, it is also possible to make a gauge (at least one of the gauges shown) asymmetrical between one half and the other half in the tire width direction with the tire equatorial plane CL as a boundary, and in that case, the range of the following gauges is also possible. It is preferable to make them different within. As shown in FIG. 6, the gauge G1 (measured in the tire radial direction) at CL on the equatorial plane of the tire is preferably 5 to 15 mm. Further, the groove depth OTD1 of the circumferential main groove closest to the tire equatorial plane CL is preferably 2 to 10 mm. Further, the gauge SBG1 from the bottom of the main groove in the circumferential direction closest to the tire equatorial plane CL to the outermost reinforcing member in the tire radial direction is preferably 0.5 to 4.5 mm. Further, the groove depth OTD2 of the outermost circumferential main groove in the tire width direction is preferably 3 to 8 mm. Further, the gauge SBG2 from the bottom of the outermost circumferential main groove in the tire width direction to the outermost reinforcing member in the tire radial direction is preferably 0.5 to 4.5 mm. Further, as shown in FIG. 6, the gauge G3 of the entire tread rubber at the tread end TE is preferably 5 to 30 mm, and the gauge G4 from the tread surface at the tread end TE to the outermost reinforcing member in the tire radial direction is It is preferably 3 to 20 mm. Here, the "tread end" means both ends in the tire width direction of the ground contact surface when the tire / wheel assembly is filled with the specified internal pressure and the maximum load is applied. Further, also at the tread end TE, the gauges G3 and G4 are measured in the normal direction of the contour line (virtual line if a groove is provided) forming the tread surface of the tread portion, but the tread end TE is the end point. In this case, the gauge G4 shall be measured in the direction connecting the tread end TE and the outermost end of the belt layer in the tire radial direction, and the gauge G3 shall also be measured in the same direction. Further, as shown in FIG. 6, the gauge G5 of the entire rubber at the midpoint of the tread end TE and the maximum tire width position in the tire width direction is preferably 2 to 10 mm, and is from the midpoint to the carcass main body. The gauge G6 is preferably 1 to 8 mm. Further, the gauge G7 at the maximum tire width position is preferably 1.0 to 8 mm. Further, the gauge G8 from the maximum tire width position to the carcass (carcass folded portion in the illustrated example) is preferably 0.5 to 5 mm. Further, the gauge G9 at the outermost point (separation point) in the tire radial direction in contact with the rim flange in the reference state is preferably 5 to 35 mm. Further, the gauge G10 from the separation point to the carcass folded portion is preferably 2 to 10 mm. For G5 to G10, each gauge is measured in the normal direction of the outer contour line of the tire.

Here, as shown in FIG. 2, the tire 10 has one or more (four in the illustrated example) circumferential main grooves 17 extending in the tire circumferential direction on the tread surface of the tread portion 13. Then, the groove depth of the circumferential main groove 17 is set to OTD, and the outermost reinforcing member in the tire radial direction from the groove bottom of the circumferential main groove 17 (in the illustrated example, the outer belt in the tire radial direction among the two belt layers). When the gauge up to layer 15B) is SBG, at least one circumferential main groove is in the above reference state.
OTD ≧ SBG
Meet.
According to this, since OTD ≧ SBG is satisfied for at least one circumferential main groove 17, among the magnetic flux generated from the transmission coil 41, the magnetic flux passing through the position of the circumferential main groove 17 is OTD. <Compared to the case of SBG, the magnetic flux trying to reach the power receiving coil 31 is less likely to be obstructed by the tread rubber, and more magnetic flux can reach the power receiving coil 31. Therefore, high power receiving efficiency can be achieved in automatic power supply using the electromagnetic induction method.
Here, the ratio OTD / SBG is preferably 1.05 or more. This is because higher power receiving efficiency can be achieved in automatic power supply using the electromagnetic induction method. For the same reason, the ratio OTD / SBG is preferably 1.3 or more. On the other hand, from the viewpoint of ensuring wear resistance, the ratio OTD / SBG is preferably 1.5 or less.
When two or more circumferential main grooves satisfy OTG ≧ SBG, the values of the ratio OTD / SBG can be the same or different depending on the positions of the circumferential main grooves.
When the circumferential main groove has OTD <SBG, the ratio OTD / SBG of the circumferential main groove is preferably 0.8 or more from the viewpoint of ensuring drainage.
Further, it is preferable that at least one circumferential main groove (satisfying OTD ≧ SBG) is located in a region where the surface of the power receiving coil is projected in a direction orthogonal to the surface. This is because even higher power receiving efficiency can be achieved in automatic power supply using the electromagnetic induction method. The at least one circumferential main groove may be located on, for example, the tire equatorial plane CL, or may be the circumferential main groove closest to the tire equatorial plane CL, corresponding to the projected region. it can. Alternatively, for example, it may be a circumferential main groove located on the outermost side in the tire width direction.
Further, it is preferable that all the circumferential main grooves located in the region where the surface of the power receiving coil is projected in the direction orthogonal to the surface satisfy OTD ≧ SBG in order to further improve the power receiving efficiency.
The OTD is preferably 2 mm or more and 10 mm or less. When the OTD is 2 mm or more, higher power receiving efficiency can be achieved in automatic power feeding using the electromagnetic induction method, while when the OTD is 10 mm or less, steering stability can be ensured. Because it can be done. For the same reason, the OTD is more preferably 3 mm or more and 8 mm or less. The SBG is preferably 0.5 mm or more and 4.5 mm or less. In the case of the same tread thickness, the cut resistance can be ensured by setting the SBG to 0.5 mm or more, while the automatic power supply using the electromagnetic induction method can be ensured by setting the SBG to 4.5 mm or less. This is because higher power receiving efficiency can be achieved. For the same reason, the SBG is more preferably 1.0 to 3.5 mm.
Most preferably, the circumferential main groove extends straight in the circumferential direction of the tire. On the other hand, the circumferential main groove may extend in the tire circumferential direction while being zigzag or curved. In this case, in order to improve the power receiving efficiency, the circumferential main groove has a groove portion extending straight and continuously in the tire circumferential direction (see-through portion (when the kick-out side is viewed from the stepping side when touching down, the groove wall). It is preferable to have a part) where the kicking side can be seen without being obstructed by the tire.
Here, the groove width (opening width) of the main groove in the circumferential direction is preferably 2% or more of the tread width TW. According to this, the drainage property can be improved. For the same reason, the groove width of the circumferential main groove is more preferably 4% or more of the tread width TW. On the other hand, from the viewpoint of ensuring the rigidity of the land portion and improving the wear resistance, the groove width of the circumferential main groove is preferably 20% or less of the tread width TW. For the same reason, the groove width of the circumferential main groove is more preferably 15% or less of the tread width TW.
Here, the "tread width" refers to the distance in the tire width direction between the tread ends when the tire / wheel assembly is filled with the specified internal pressure and put into a no-load state.
Although not particularly limited, the groove width (opening width) of the circumferential main groove is preferably 3 mm or more. This is because the power receiving efficiency can be further improved. For the same reason, the groove width of the circumferential main groove is more preferably 5 mm or more, although it is not particularly limited. On the other hand, from the viewpoint of ensuring the rigidity of the land portion and improving the wear resistance, the groove width of the circumferential main groove is preferably 30 mm or less, although it is not particularly limited. For the same reason, the groove width of the circumferential main groove 17 is more preferably 20 mm or less.
The tread portion 13 may not have a width direction groove extending in the tire width direction, or may be provided with one or more width direction grooves. Further, the tread portion 13 may not have a circumferential sipe extending in the tire circumferential direction or a width sipe extending in the tire width direction, or one or more circumferential sipe and / or one or more. It is also possible to provide a tire in the width direction of. The groove in the width direction is a groove extending in the tire width direction, and the groove width (opening width) when the tire / wheel assembly is filled with the specified internal pressure and no load is applied is 2 mm or more. The circumferential sipe refers to a tire / wheel assembly having a groove width (opening width) of less than 2 mm when the tire / wheel assembly is filled with a specified internal pressure and no load is applied. The width direction sipe refers to a tire / wheel assembly having a groove width (opening width) of less than 2 mm when the specified internal pressure is applied and no load is applied.
The groove width (opening width) of the groove in the width direction is not particularly limited in order to achieve both drainage performance and cornering performance, but can be, for example, 1 to 15 mm. For the same reason, the groove width of the groove in the width direction is more preferably 2 to 10 mm.
Further, the groove depth (maximum depth) of the groove in the width direction is not particularly limited in order to achieve both wear performance and steering stability performance, but can be, for example, 2 to 10 mm. For the same reason, the groove depth of the widthwise groove is more preferably 3 to 8 mm.
In the tread of the tire, the groove that is connected without being divided in the middle from one side in the tire circumferential direction to the other side is a circumferential groove (including the circumferential main groove), and the other grooves are in the width direction. Make a groove.
The negative rate of the entire tread portion 13 of the tread portion 13 is not particularly limited, but can be 8 to 40%. Drainage can be further improved by setting the negative rate of the entire tread of the tread portion 13 to 8% or more, while wear resistance can be improved by setting the negative rate of the entire tread of the tread portion 13 to 40% or less. Can be enhanced. For the same reason, the negative rate of the entire tread portion 13 of the tread portion 13 is more preferably 15 to 35%.
Here, the "tread surface" refers to a surface of the ground contact surface that comes into contact with the road surface over the entire tire circumferential direction when the tire / wheel assembly is filled with the specified internal pressure and the maximum load is applied.
The "circumferential main groove" is a groove extending in the circumferential direction of the tire, and the groove width (opening width) when the tire / wheel assembly is filled with the specified internal pressure and no load is applied is 2 mm or more. To say.
Further, the "groove depth OTD of the circumferential main groove" is the circumferential main groove measured in the normal direction of the contour line (virtual line if a groove is provided) forming the tread surface of the tread portion in the above reference state. It shall mean the maximum depth.
Further, the "gauge SBG from the bottom of the main groove in the circumferential direction to the outermost reinforcing member in the tire radial direction" is a line segment forming the above OTD in a state where the internal pressure of the tire / wheel assembly is 0 kPa and no load is applied. The distance from the bottom of the main groove in the circumferential direction to the outermost reinforcing member in the tire radial direction of the extension line of. The reinforcing member may be, for example, a belt, or may be, for example, a belt reinforcing layer arranged on the outer side of the belt in the tire radial direction.

As a result of diligent studies by the present inventor, since the power receiving coil (and in some cases, the in-wheel motor) is mounted on the tire / wheel assembly as described above, the load supported by the tire becomes large, and the tire becomes large. It was found that the shoulder part of the tire is greatly distorted and heat is generated, which may reduce the durability of the tire.
Therefore, the tire 10 may have a reinforcing member (belt 15 in this example) made of one or more reinforcing layers (two belt layers 15A and 15B in this example) made of a rubberized layer of the cord. preferable. Here, in the above reference state, from both ends in the tire width direction of the maximum width reinforcing layer (in this example, the innermost belt layer 15A in the tire radial direction) having the maximum width in the tire width direction among one or more reinforcing layers. The area outside the tire width direction is defined as the shoulder area from the position where the maximum width reinforcing layer is separated by 5% of the width in the tire width direction inside the tire width direction. At this time, in the present embodiment, in the above reference state, the cord end (not shown in FIG. 2) of at least one reinforcing layer (in this example, both the belt layers 15A and 15B) is larger than the shoulder region. It is located inside in the tire width direction. According to this, in the tire 10, in the above reference state, the cord end (not shown in FIG. 2) of at least one reinforcing layer (in this example, both the belt layers 15A and 15B) is from the shoulder region. Is also located inside in the tire width direction. Therefore, the cord end, which tends to be the core of the failure, is not positioned in the shoulder region where the strain increases due to the increase in the load due to the power receiving coil 31, and the failure generated from the cord end is suppressed, so that the durability of the tire is maintained. Can be improved.
If the cord end of at least one reinforcing layer is located inside the shoulder region in the tire width direction, the above effect can be obtained for the reinforcing layer. Further, if the cord end is located inside the shoulder area in the tire width direction at least one of the start end and the end of the cord end, the above effect can be obtained for the end, and the cord end can be obtained. If the cord end is located inside the shoulder area in the tire width direction at both the start end and the end end, the above effect can be obtained at both ends.
Here, as in the above example, it is preferable that the cord ends of all the reinforcing layers are located inside the shoulder region in the tire width direction in the reference state. This is because the durability of the tire can be further improved by suppressing the failure that occurs from the end of the cord for all the reinforcing layers.
Further, in the reference state, the cord ends of at least one reinforcing layer are 10% of the width of the maximum width reinforcing layer in the tire width direction inward from both ends in the tire width direction of the maximum width reinforcing layer in the tire width direction in the reference state. It is preferably located inside the tire width direction rather than the separated tire width direction position. This is because the cord end can be moved further away from the shoulder region to suppress failures that occur from the cord end and further improve the durability of the tire.
Further, in the reference state, the cord ends of all the reinforcing layers are separated from both ends of the maximum width reinforcing layer in the tire width direction inward in the tire width direction by 10% of the width of the maximum width reinforcing layer in the tire width direction. It is preferably located inside the tire width direction rather than the tire width direction position. This is because, for all the reinforcing layers, the cord end can be further moved from the shoulder region to suppress the failure generated from the cord end, and the durability of the tire can be further improved.
FIG. 7 is a plan view showing the configuration of the inclined belt layer. As shown in FIG. 7, in the reinforcing member (tilt belt), the strip member 15a extends from one widthwise end toward the other widthwise end, is folded back at the other widthwise end, and is the other. Repeatedly extending from the width end to one width end, folding at one width end, and extending from one width end to the other width end. It is preferable that the tire is spirally wound in the circumferential direction (so-called endless belt structure). At this time, the strip member is separated from the widthwise end of the reinforcing layer (belt layer) by an appropriately set distance (separated position) so that the ends (starting end and / or ending) of the strip member are not located in the shoulder region. By starting or ending the winding, the cord end can be located inside the shoulder area in the tire width direction. The position in the tire width direction at the beginning of the cord end may be the same as or different from the position in the tire width direction at the end of the cord end.
Here, the reinforcing layer is preferably an inclined belt layer in which the cord is inclined with respect to the tire circumferential direction, and the reinforcing member is preferably an inclined belt. This is because when the reinforcing layer is an inclined belt, failure from the cord end of the inclined belt can be suppressed and the durability of the tire can be improved. The inclination angle of the cord with respect to the tire circumferential direction is not particularly limited, but may be 5 to 45 ° with respect to the tire circumferential direction.
Alternatively, it is also preferable that the reinforcing layer is a circumferential belt layer in which the cord extends along the tire circumferential direction, and the reinforcing member is a circumferential belt. In this case, the width of the circumferential belt layer in the tire width direction may be adjusted so that the outermost cord in the tire width direction is located inside the shoulder region in the tire width direction. As a result, when the reinforcing layer is a circumferential belt, it is possible to suppress a failure from the cord end of the circumferential belt and improve the durability of the tire.
Alternatively, the reinforcing layer is an inclined belt layer in which the cord is inclined with respect to the tire circumferential direction, and a circumferential direction in which the cord extends along the tire circumferential direction, which is arranged outside or inside the inclined belt layer in the tire radial direction. It is also preferable that the belt layer and the reinforcing member are the inclined belt and the circumferential belt arranged on the outer side or the inner side in the tire radial direction of the inclined belt and the inclined belt. Even in a configuration in which a circumferential belt is provided on the outer or inner side of the inclined belt in the tire radial direction, failure from the cord end of the inclined belt layer and / or the circumferential belt layer can be suppressed, and the durability of the tire can be improved. Because.

Further, it is preferable that the tire 10 has a reinforcing member (inclined belt 15 in this example) composed of two or more reinforcing layers (inclined belt layer in this example) composed of a rubberized layer of the cord.
As shown in FIG. 8, the cord end (for example, the cord end and the tire width direction end of the reinforcing layer) of at least one reinforcing layer (belt layer 15B on the outer side in the tire radial direction of the two belt layers in the illustrated example). The position in the tire width direction is the same as that of the other reinforcing layer (belt layer 15A in the illustrated example) located inside the tire radial direction from the at least one reinforcing layer (belt layer 15B in the illustrated example). The end is folded back from the inside to the outside in the tire radial direction and terminated on the outer side in the tire radial direction from at least one belt layer (belt layer 15B in the illustrated example) to terminate the other reinforcing layer (belt layer 15B in the illustrated example). ) Surrounded by. (Note that the ends of the other reinforcing layers located outside the tire radial direction from at least one belt layer are folded back from the tire radial outside to the inside, and are terminated inside the tire radial direction from at least one reinforcing layer. Thereby, the structure may be surrounded by another reinforcing layer.)
In this example, the cord end of at least one reinforcing layer is surrounded by another reinforcing layer with the other reinforcing layer folded from the inside to the outside in the tire radial direction or from the outside to the inside in the tire radial direction.
According to this, in the tire 10, the cord end of at least one reinforcing layer is surrounded by the other reinforcing layer with the other reinforcing layer folded back from the inside to the outside in the tire radial direction or from the outside to the inside in the tire radial direction. Has been done. As a result, even when the cord end is located in the shoulder region where the strain increases due to the increase in load due to having the power receiving coil 31, for example, the cord end is surrounded by another reinforcing layer as described above. Thereby, the cord end can be protected from distortion, the failure generated from the cord end can be suppressed, and the durability of the tire can be improved.
In particular, as in the example shown in FIG. 8, the cord end of at least one reinforcing layer (belt layer 15B on the outer side in the tire radial direction among the two belt layers in the illustrated example) is the reinforcing layer of at least one layer. The end of another reinforcing layer (belt layer 15A in the illustrated example) located inside the tire radial direction from the (belt layer 15B in the illustrated example) is folded back from the inside to the outside in the tire radial direction, and at least one belt layer (belt layer 15A). In the illustrated example, it is preferable that the tire is terminated on the outer side in the tire radial direction from the belt layer 15B) and is surrounded by another reinforcing layer (belt layer 15B in the illustrated example). According to this, it is possible to improve exercise performance such as cornering performance.
Further, as in the present embodiment, the reinforcing layer is preferably an inclined belt layer in which the cord is inclined with respect to the tire circumferential direction. At this time, the inclination angle of the cord with respect to the tire circumferential direction is not particularly limited, but can be, for example, 5 to 45 ° with respect to the tire circumferential direction.
The reinforcing layer of at least one layer surrounding the cord end may be a circumferential belt layer in which the cord extends along the tire circumferential direction, and in this case as well, failure of the circumferential belt layer from the cord end is suppressed. Therefore, the durability of the tire can be improved.
Further, in the above example, the case where the cord end and the tire width direction end of the reinforcing layer are the same in the tire width direction is shown, but they may be different, and in this case as well, the cord end is due to another reinforcing layer. If it is surrounded as described above, the above-mentioned effects can be obtained.
FIG. 9 is a cross-sectional view of a tire of another example in the tire width direction. 10A and 10B are perspective views for explaining the reinforcing member of FIG. 9.
As shown in FIGS. 9, 10A and 10B, at least one reinforcing layer (belt layer 15C in FIG. 9) is an annular core reinforcing layer, and another reinforcing layer (belt layer 15D in FIG. 9). Extends from one widthwise end of the core reinforcing layer 15C toward the other widthwise end, and is folded back from the tire radial inside to the outside at the other widthwise end, with reference to FIG. 10A. , Extending from the other widthwise end to one widthwise end, at one widthwise end, folded back from the tire radial outside to the inside, from one widthwise end to the other widthwise end It is preferable that the sheath reinforcing layer is spirally wound in the tire circumferential direction so that it extends toward the tire repeatedly (the completed state is FIG. 10B). The core reinforcing layer can be composed of one or more reinforcing layers composed of a rubberized layer of an organic fiber cord, or a single rubber, and is preferably a rubberized layer of a cord.
Even with such a configuration, the tire 10 has at least one reinforcing layer in which the cord end of the other reinforcing layer is folded back from the inside to the outside in the tire radial direction or from the outside to the inside in the tire radial direction to form another reinforcing layer. Surrounded by. As a result, even when the cord end is located in the shoulder region where the strain increases due to the increase in load due to having the power receiving coil 31, for example, the cord end is surrounded by another reinforcing layer as described above. Thereby, the cord end can be protected from distortion, the failure generated from the cord end can be suppressed, and the durability of the tire can be improved.
In particular, as in this example, at least one reinforcing layer (belt layer 15C) is an annular core reinforcing layer, and the other reinforcing layer (belt layer 15D) is one end in the width direction of the core reinforcing layer. Extends from the other widthwise end to the other widthwise end, folded back from the tire radial inside to the outside, and extends from the other widthwise end towards one widthwise end. Spiral in the tire circumferential direction so that at one width end, the tire is folded inward from the outside in the radial direction and extends from one width end to the other width end repeatedly. It is also preferable that the sheath reinforcing layer is in a wound state. Thereby, the durability of the belt can be improved.
In the examples shown in FIGS. 9, 10A and 10B, the core reinforcing layer extends with the cord extending along the tire circumferential direction or tilting at an inclination angle of 30 to 90 ° with respect to the tire circumferential direction. It is a core belt layer, and the sheath reinforcing layer is preferably a sheath belt layer in which the cord extends at an inclination angle of 45 ° or less with respect to the tire circumferential direction. Further, it is more preferable that the inclination angle of the cord of the core belt layer with respect to the tire width direction is smaller than the inclination angle of the cord of the sheath belt layer with respect to the tire width direction.

Here, it is preferable that the tire 10 has a reinforcing member (inclined belt 15 in this example) composed of two or more reinforcing layers (inclined belt layer in this example) made of a rubberized layer of the cord. FIG. 11 is a cross-sectional view showing the inclined belt layer and the interlayer rubber.
As shown in FIG. 11, among the layers of the two reinforcing layers adjacent in the tire radial direction, at least one layer (in the example shown in FIG. 11, the layer between the belt layer 15A and the belt layer 15B) is divided into two layers. The interlayer rubber 19 extends to the tire width direction region including the tire width direction end of the reinforcement layer (belt layer 15B in the illustrated example) located on the outer side in the tire radial direction. As a result, even when the cord end of the belt layer is located in the shoulder region where the strain increases due to the increase in the load due to having the power receiving coil 31, for example, the interlayer rubber 19 absorbs the strain, and the two layers Since the distance between the cord ends of the belt layer can be secured by the amount of the interlayer rubber 19 arranged, failures that occur from the cord ends (particularly the cord ends of the belt layer 15B on the outer side in the tire radial direction) can be suppressed. , The durability of the tire can be improved. In this example, the positions of the cord end and the tire width direction end of each inclined belt layer are the same.
Further, the interlayer rubber may extend from the end of the reinforcing layer located inside the tire radial direction to the outside in the tire width direction of the two reinforcing layers, or extend to the inside in the tire width direction. It may be the same, or the position in the tire width direction may be the same.
The interlayer rubber may or may not cover the end face of the reinforcing layer located on the outer side in the tire radial direction of the two reinforcing layers, or may not cover the reinforcing layer as shown in the drawing.
Here, the 100% modulus of the interlayer rubber is preferably 3.0 MPa or more. This is because the possible distortion can be sufficiently absorbed, the failure generated from the cord end can be further suppressed, and the durability of the tire can be further improved. For the same reason, the 100% modulus of the interlayer rubber is preferably 5.0 MPa or more. On the other hand, from the viewpoint of reducing the rigidity step with the surrounding rubber, the 100% modulus of the interlayer rubber is preferably 20.0 MPa or less.
Further, it is preferable that the interlayer rubber is in the form of a sheet and the maximum thickness in the tire radial direction is 3 mm or less. This is because the weight increase due to the interlayer rubber can be suppressed. For the same reason, the maximum thickness of the interlayer rubber is more preferably 2 mm or less. On the other hand, from the viewpoint of sufficiently absorbing the strain that may occur, the maximum thickness of the interlayer rubber is preferably 0.5 mm or more.
Further, in the cross section in the tire width direction, it is preferable that the thickness of the interlayer rubber gradually increases in the tire radial direction from the inside to the outside in the tire width direction. This is because the distance between the belt layers can be further secured on the end side of the belt layer, the failure generated from the cord end can be further suppressed, and the durability of the tire can be further improved. On the other hand, the thickness of the interlayer rubber can be constant when viewed in cross section in the tire width direction.
Here, the two-layer reinforcing layer in which the interlayer rubber is arranged between the layers is preferably a two-layer inclined belt layer in which the cord extends at an inclination angle of 20 to 70 ° with respect to the tire circumferential direction. .. This is because when the reinforcing layer is an inclined belt layer, it is possible to suppress a failure that occurs from the cord end of the inclined belt layer and improve the durability of the tire.
Alternatively, the two layers of reinforcing layers in which the interlayer rubber is arranged between the layers are a one-layer inclined belt layer in which the cord extends at an inclination angle of 45 ° or less with respect to the tire width direction, and the cord extends in the tire circumferential direction. It is also preferable that the belt layer is one layer extending along the circumferential direction. This is because when the reinforcing layer is the inclined belt layer and the circumferential belt layer, it is possible to suppress the failure generated from the cord end of the inclined belt layer and the circumferential belt layer and improve the durability of the tire.
Alternatively, the two-layer reinforcing layer in which the interlayer rubber is arranged between the layers is preferably a two-layer circumferential belt layer in which the cord extends along the tire circumferential direction. This is because when the reinforcing layer is the circumferential belt layer, it is possible to suppress a failure that occurs from the cord end of the circumferential belt layer and improve the durability of the tire.

Further, as examined by the present inventor, when foreign matter invades between the road surface and the tire during power supply (particularly, foreign matter from the stepping side or kicking side invades), the magnetic flux is hindered by the foreign matter and power is received. It turns out that there is a risk of reduced efficiency.
Therefore, the tire 10 has a belt 15 composed of one or more layers (two layers in the illustrated example), and is loaded with the above load load state (the tire / wheel assembly is filled with the specified internal pressure and the maximum load load is applied. When the outermost point of the ground contact surface in the tire width direction is the ground contact end E, as shown in FIG. 12, the width in the tire width direction is the smallest among the one or more belt layers in the above reference state. The width W1 in the tire width direction of the minimum width belt layer (belt layer 15B in the illustrated example) is smaller than the ground contact width W2, which is the distance in the tire width direction between the ground contact ends E, or the tire width direction of the minimum width belt layer. The width W1 of is preferably equal to the ground contact width W2. As a result, the deformation of the shoulder portion of the tire becomes large (relative to the case of W1> W2), and the contact length of the shoulder portion becomes long. This makes it difficult for foreign matter to enter between the road surface and the tire (particularly from the stepping side or kicking side) during power supply, and it is possible to suppress a decrease in power receiving efficiency due to the foreign matter hindering the magnetic flux.
The ratio W1 / W2 is preferably 0.98 or less. This is because the ground contact length of the shoulder portion becomes longer, it becomes difficult for foreign matter to enter, and the decrease in power receiving efficiency can be further suppressed. For the same reason, the ratio W1 / W2 is more preferably 0.9 or less, and further preferably 0.7 or less. On the other hand, from the viewpoint of enhancing the tagging effect of the belt and improving the steering stability, the ratio W1 / W2 is preferably 0.5 or more.

Further, as examined by the present inventor, if foreign matter enters between the road surface and the tire during power supply (particularly, foreign matter from the width direction invades), the magnetic flux is hindered by the foreign matter, and the power receiving efficiency is lowered. It turned out that there is a risk of getting tired.
Therefore, when the tire 10 has a belt 15 composed of one or more layers (two layers in the illustrated example), and the outermost point of the ground contact surface in the tire width direction in the above load state is the ground contact end E, As shown in FIG. 13, in the above reference state, the width W1 in the tire width direction of the minimum width belt layer (belt layer 15B in the illustrated example) having the smallest width in the tire width direction among one or more belt layers is It is also preferable that the contact patch width is larger than the contact patch width W2, which is the distance between the contact patch E in the tire width direction. As a result, the deformation of the shoulder portion of the tire is suppressed (relatively as compared with the case of W1 ≦ W2), the contact length of the shoulder portion is reduced, and the contact width is increased. This makes it difficult for foreign matter to enter between the road surface and the tire (particularly from the width direction) during power supply, and it is possible to suppress a decrease in power receiving efficiency due to the foreign matter hindering the magnetic flux.
The ratio W1 / W2 is preferably 1.02 or more. This is because the ground contact width is further increased, it becomes difficult for foreign matter to enter, and the decrease in power receiving efficiency can be further suppressed. For the same reason, the ratio W1 / W2 is more preferably 1.2 or more, and further preferably 1,3 or more. On the other hand, from the viewpoint of suppressing the weight increase due to the belt layer, the ratio W1 / W2 is preferably 1.5 or less.

Here, with reference to FIG. 13, in the above reference state, the tire width direction end of the minimum width belt layer (belt layer 15B in the illustrated example) having the minimum width in the tire width direction among one or more belt layers is Of one or more circumferential main grooves 17, it is also preferable that the tires are located on the outermost side in the tire width direction with respect to the outermost peripheral main groove 17 located on the outermost side in the tire width direction. As a result, deformation of the shoulder portion of the tire is suppressed (relative to the case where the tire width direction end of the minimum width belt layer is located inside the tire width direction with respect to the outermost circumferential main groove), and the shoulder portion is suppressed. The ground contact length of the part decreases and the ground contact width increases. This makes it difficult for foreign matter to enter between the road surface and the tire (particularly from the width direction) during power supply, and it is possible to suppress a decrease in power receiving efficiency due to the foreign matter hindering the magnetic flux.
Here, in the above reference state, the tire width direction end of the minimum width belt layer is preferably located 2 mm or more outside the tire width direction with respect to the outermost peripheral main groove. By setting it to 2 mm or more, the ground contact width is further increased, it becomes more difficult for foreign matter to enter between the road surface and the tire (especially from the width direction), and the decrease in power receiving efficiency due to the foreign matter hindering the magnetic flux is further suppressed. Because it can be done. For the same reason, in the above reference state, it is more preferable that the end of the minimum width belt layer in the tire width direction is located 5 mm or more outside the main groove in the outermost circumferential direction in the tire width direction. On the other hand, from the viewpoint of suppressing the weight increase due to the belt layer, the tire width direction end of the minimum width belt layer is preferably located 20 mm or less outside the tire width direction with respect to the outermost peripheral main groove.

Further, the tire 10 has a belt made of one or more belt layers made of a rubberized layer of a cord made of organic fibers (aramid fiber in this example), and the number of cords driven in the (each) belt layer is 10. It is preferably ~ 50/50 mm. If the number of cords driven in the belt layer exceeds 50/50 mm, the rate of propagation of distortion between the cords increases, which may cause a failure. On the other hand, if the number of cords driven in the belt layer is less than 10/50 mm, rubber has a lower magnetic permeability than organic fibers and easily interferes with the magnetic flux from the power transmission coil 31, which causes a decrease in power receiving efficiency. Become. On the other hand, by setting the number of cords driven in the belt layer within the above range, it is possible to improve the durability of the tire while improving the power receiving efficiency.
In some cases, the number of cords driven in the belt layer is preferably 15 to 45 cords / 50 mm. For example, in a tire / wheel assembly used for automatic driving, it is possible to run sufficiently even if the tag effect of the belt is not so large, and it is considered that improvement in power receiving efficiency is particularly desired. Therefore, high power receiving efficiency can be achieved by setting the number of belt cords to be driven in to 15 lines / 50 mm or more, while setting the number of belt layer cords to be driven in to 45 lines / 50 mm or less. , While further improving the durability of the tire, it is possible to sufficiently secure the running performance of the tire. The tire / wheel assembly used for autonomous driving may include, for example, an in-wheel motor.
As the organic fiber, for example, aramid fiber, PET fiber, nylon fiber and the like can be used.

Here, due to the arrangement of the power receiving coil and the power transmitting coil, the inside of the tire / wheel assembly when mounted on the vehicle may be the passage path of the magnetic flux.
As shown in FIG. 17, the tire 10 has a belt made of one or more belt layers made of a rubberized layer of a cord made of organic fibers, and in the above reference state, the tire width among the one or more belt layers. In the minimum width belt layer (belt layer 15B in the illustrated example) having the minimum width in the direction, the width Wa of the minimum width belt layer in the tire width direction in the tire width direction half portion inside the vehicle mounting is different from that of the vehicle mounting outside. It is preferable that the width Wb of the minimum width belt layer in the tire width direction half portion is larger than the width Wb in the tire width direction.
Here, in this example, organic fiber is used for the cord of the belt layer, and the magnetic permeability is higher than that of rubber. Therefore, when the belt layer is arranged, the magnetic flux from the power transmission coil 31 is less likely to be hindered.
Therefore, in this example, the magnetic flux from the power transmission coil 31 is less likely to be obstructed in the half portion in the tire width direction inside the vehicle. Therefore, according to this example, high power receiving efficiency can be achieved in automatic power feeding using the electromagnetic induction method.
Here, the width of the minimum width belt layer in the tire width direction is preferably 102% or more of the ground contact width. As described above, when the belt layer is arranged, the magnetic flux from the power transmission coil 31 is less likely to be obstructed. Therefore, by setting the tire width direction region to 102% or more of the ground contact width, the power receiving efficiency can be further improved. Because it can be done. For the same reason, the width of the minimum width belt layer in the tire width direction is more preferably 105% or more, and further preferably 125% or more of the ground contact width. On the other hand, from the viewpoint of suppressing the weight increase due to the belt layer, the width of the minimum width belt layer in the tire width direction is preferably 135% or less of the ground contact width.
The ratio Wa / Wb is preferably 1.1 or more. This is because the magnetic flux from the power transmission coil 31 can be made less likely to be obstructed in the half portion in the tire width direction inside the vehicle mounting, and the power receiving efficiency can be further improved. For the same reason, the ratio Wa / Wb is more preferably 1.2 or more, and even more preferably 1.3 or more. On the other hand, from the viewpoint of suppressing the weight increase due to the belt layer, the ratio Wa / Wb is preferably 1.5 or less.
If the magnetic flux can pass through the inside of the belt layer mounted on the vehicle at the time of power feeding, high power feeding efficiency can be achieved by the above-mentioned action and effect. For example, when a part or the whole of the power receiving coil 31 is arranged inside the vehicle mounting, or for example, a part or the whole of the power receiving coil 31 is arranged outside the vehicle mounting, but the surface of the power receiving coil. This is particularly effective when the axial direction perpendicular to the tire is inclined inward when the vehicle is mounted from the inside to the outside in the radial direction of the tire.
As the organic fiber, for example, aramid fiber, PET fiber, nylon fiber and the like can be used.

On the other hand, due to the arrangement of the power receiving coil and the power transmitting coil, the outside of the tire / wheel assembly when mounted on the vehicle may be the passage path of the magnetic flux.
As shown in FIG. 18, the tire 10 has a belt made of one or more belt layers made of a rubberized layer of a cord made of organic fibers, and in the above reference state, the tire width among the one or more belt layers. In the minimum width belt layer (belt layer 15B in the illustrated example) having the minimum width in the direction, the width Wb of the minimum width belt layer in the tire width direction in the tire width direction half portion on the outside of the vehicle mounting is the inside of the vehicle mounting. It is also preferable that the width Wa of the minimum width belt layer in the tire width direction half portion is larger than the width Wa in the tire width direction.
In this example, the width Wb in the tire width direction of the minimum width belt layer in the tire width direction half portion on the outside of the vehicle mounting is the tire width direction of the minimum width belt layer in the tire width direction half portion on the vehicle mounting inside. It is larger than the width Wa. Here, in the present embodiment, organic fibers are used for the cord of the belt layer, and the magnetic permeability is higher than that of rubber. Therefore, when the belt layer is arranged, the magnetic flux from the power transmission coil 31 is less likely to be hindered.
Therefore, in this example, the magnetic flux from the power transmission coil 31 is less likely to be obstructed in the tire width direction half portion outside the vehicle mounting. Therefore, according to this example, high power receiving efficiency can be achieved in automatic power feeding using the electromagnetic induction method.
Here, the width of the minimum width belt layer in the tire width direction is preferably 102% or more of the ground contact width. As described above, when the belt layer is arranged, the magnetic flux from the power transmission coil 31 is less likely to be obstructed. Therefore, by setting the tire width direction region to 102% or more of the ground contact width, the power receiving efficiency can be further improved. Because it can be done. For the same reason, the width of the minimum width belt layer in the tire width direction is more preferably 105% or more, and further preferably 125% or more of the ground contact width. On the other hand, from the viewpoint of suppressing the weight increase due to the belt layer, the width of the minimum width belt layer in the tire width direction is preferably 135% or less of the ground contact width.
The ratio Wb / Wa is preferably 1.1 or more. This is because the magnetic flux from the power transmission coil 31 can be made less likely to be obstructed in the half portion in the tire width direction on the outer side of the vehicle mounting, and the power receiving efficiency can be further improved. For the same reason, the ratio Wb / Wa is more preferably 1.2 or more, and even more preferably 1.3 or more. On the other hand, from the viewpoint of suppressing the weight increase due to the belt layer, the ratio Wb / Wa is preferably 1.5 or less.
If the magnetic flux can pass through the outside of the belt layer mounted on the vehicle at the time of power feeding, high power feeding efficiency can be achieved by the above-mentioned action and effect. For example, when a part or the whole of the power receiving coil 31 is arranged on the outside of the vehicle mounting, or for example, a part or the whole of the power receiving coil 31 is arranged on the inside of the vehicle mounting, but the surface of the power receiving coil. This is particularly effective when the axial direction perpendicular to the tire is inclined outward when the vehicle is mounted from the inside to the outside in the radial direction of the tire.
As the organic fiber, for example, aramid fiber, PET fiber, nylon fiber and the like can be used.

As a result of examination by the present inventor, it has been found that it is required to improve the traumatic resistance of the tire in view of the fact that the power receiving coil is mounted.
The tire 10 includes a carcass 14 composed of one or more carcass plies straddling a pair of bead cores in a toroidal shape, and the carcass ply extends from the carcass main body portion 14A straddling the pair of bead cores in a toroidal shape and the carcass main body portion. It is preferable that the bead core is composed of a carcass folded portion 14B that is folded outward from the inside in the tire width direction of the bead core and extends outward in the tire radial direction. According to this, the carcass ply extends from the carcass main body 14A that straddles the pair of bead cores in a toroidal shape and the carcass main body, and is folded back from the inside to the outside in the tire width direction of the bead core to have a tire diameter. It consists of a carcass folded-back portion 14B extending outward in the direction. As a result, the carcass folded-back portion 14B can protect the members such as the carcass main body and the power receiving coil from trauma (particularly at the sidewall portion) of the tire, and can improve the trauma resistance of the tire.
FIG. 14A is a schematic view showing an example of the carcass structure. As shown in FIG. 14A, in the above reference state, the end of the carcass folded portion is from the inner end in the tire radial direction in the tire radial region forming the tire cross-sectional height SH, to the outer side in the tire radial direction from the inner end in the tire radial direction. It is preferably located in the tire radial region up to a position separated by less than 1/4 of the tire cross-sectional height SH. This is because the weight increase due to the carcass can be suppressed while improving the trauma resistance as described above.
FIG. 14B is a schematic view showing another example of the carcass structure. As shown in FIG. 14B, in the above reference state, the end of the carcass folded portion is 1 / of the tire cross-sectional height SH from the inner end in the tire radial direction to the outer side in the tire radial direction in the tire radial region forming the tire cross-sectional height SH. It is also preferable that the tire is located in the tire radial region from a position separated by 4 or more to a position separated from the inner end in the tire radial direction to the outer side in the tire radial direction by less than 3/4 of the tire cross-sectional height SH. Compared with the case shown in FIG. 14A, the carcass folded portion increases the tire radial region that can be protected from trauma, so that the trauma resistance of the tire can be further improved. In the case of the carcass structure shown in FIG. 14B, the position of the end of the carcass folded portion in the tire radial direction can be the tire radial position of the tire maximum width position P, or the tire maximum width position as shown in the drawing. It may be inside the tire radial direction from P, or it may be outside the tire radial direction from the maximum tire width position P.
FIG. 14C is a schematic diagram showing another example of the carcass structure. As shown in FIG. 14C, in the above reference state, the end of the carcass folded portion is 3 / of the tire cross-sectional height SH from the inner end in the tire radial direction to the outer side in the tire radial direction in the tire radial region forming the tire cross-sectional height SH. It is also preferable that the tire is located on the outer side in the tire radial direction rather than the position separated by 4. Compared with the case shown in FIG. 14B, the tire radial region that can be protected from trauma by the carcass folded portion is further increased, so that the trauma resistance of the tire can be further improved.
In this case, the end of the carcass folded portion is located inside the tire width direction end of the maximum width belt layer having the maximum width in the tire width direction among one or more belt layers, that is, a so-called envelope structure. According to this, the trauma resistance of the tire can be particularly enhanced.
Here, in the cross-sectional view in the tire width direction in the above reference state, the gauge of the sidewall rubber measured in the normal direction of the contour line of the tire outer surface from the tire outer surface at the tire maximum width position is 0.5 to 5 mm. Is preferable.
When power is transmitted from the power transmission coil to the power reception coil by the electromagnetic induction method, the gauge is set to 0 in order to reduce the amount of magnetic flux blocked by the sidewall rubber and to reduce the weight of the tire. It is conceivable to make it relatively thin as 5 to 5 mm. Then, in such a case, it has been found that the problem of failure of members such as the carcass main body and the power receiving coil due to trauma can become remarkable.
Therefore, when the gauge is 5 mm or less, it is particularly effective to enhance the traumatic property of the tire by having the carcass folded portion (for example, as shown in each of the above examples).
The gauge is preferably 1.0 mm or more from the viewpoint of generating appropriate bending or the like as the sidewall portion of the tire.

Further, the tire 10 includes a pair of bead portions and a carcass made of one or more carcass plies straddling the pair of bead portions in a toroidal shape. The number of cords driven is preferably 10 to 50/50 mm. If the number of cords driven in the carcass ply exceeds 50/50 mm, the rate of propagation of distortion between the cords increases, which may cause a failure. On the other hand, if the number of carcass ply cords driven is less than 10/50 mm, rubber has a lower magnetic permeability than organic fibers and easily interferes with the magnetic flux from the power transmission coil 31, which causes a decrease in power receiving efficiency. Become. On the other hand, by setting the number of carcass ply cords driven in the above range, it is possible to improve the durability of the tire while improving the power receiving efficiency.
Here, it may be preferable that the number of carcass ply cords driven is 15 to 45/50 mm. For example, in a tire / wheel assembly used for automatic driving, it is possible to run sufficiently even if the strength of the carcass as a tire skeleton is not so high, and it is considered that improvement in power receiving efficiency is particularly desired. .. Therefore, high power receiving efficiency can be achieved by setting the number of carcass ply cords driven in to 15 lines / 50 mm or more, while setting the number of carcass ply cords driven in to 45 lines / 50 mm or less. , While further improving the durability of the tire, it is possible to sufficiently secure the running performance of the tire. The tire / wheel assembly used for autonomous driving may include, for example, an in-wheel motor.
As the organic fiber, for example, aramid fiber, PET fiber, nylon fiber and the like can be used.

As a result of examination by the present inventor, it has been found that it is preferable to protect the tire member and the power receiving coil from trauma, especially when the flatness of the tire is 75% or less.
Therefore, as shown in FIG. 15, the flatness of the tire 10 is 75% or less, and it is preferable that the side reinforcing rubber 60 is arranged on the sidewall portion 12 of the tire 10. In this example, since the flatness of the tire 10 is 75% or less, the distance between the ground contact surface and the wheel 20 becomes closer (relative to the tire having a large flatness) under load. Therefore, when the tire is significantly deformed, such as when riding on a curb or the like, a large load may be applied to the wheel 20. On the other hand, in the present embodiment, since the side reinforcing rubber 60 is arranged on the sidewall portion 12 of the tire 10, the sidewall portion 12 of the tire is reinforced by the side reinforcing rubber 60 to the wheel 20. The load can be reduced. In particular, when the power receiving coil 31 is provided on the rim portion, damage to the power receiving coil 31 can be suppressed. In this way, the trauma resistance can be improved.
Here, the flatness of the tire is preferably 70% or less, more preferably 65% or less, further preferably 60% or less, and particularly preferably 55% or less. Since the problem that a large load may be applied to the wheel described above becomes more prominent, it is particularly preferable to arrange the side reinforcing rubber on the sidewall portion of the tire 10 to reduce the load on the wheel as described above. This is because it is valid.
Here, the tire includes a pair of bead portions and a carcass straddling the pair of bead portions in a toroidal shape, and the side reinforcing rubber is between the carcass and the inner surface of the tire (inner liner in the illustrated example) in the tire width direction. It is preferably arranged in. As a result, the carcass can be protected by the side reinforcing rubber, and the trauma resistance of the tire can be improved.
Further, in the cross-sectional view in the tire width direction, the side reinforcing rubber preferably has a crescent-shaped cross section. As a result, when the tire is punctured, the side reinforcing rubber can take over the load and run.

As a result of the study by the present inventor, it is considered that run-flat durability is required even in the technique using the electromagnetic induction method.
Therefore, as shown in FIG. 15, the sidewall portion 12 of the tire 10 is provided with the side reinforcing rubber 60, and in the above reference state, the inner end of the side reinforcing rubber 60 in the tire width direction is inside the ground contact end E in the tire width direction. It is preferably located at. As a result, when the tire is punctured, the side reinforcing rubber 60 can sufficiently exert the effect of running by taking over the load, and the run-flat durability can be improved.
Here, the inner end of the side reinforcing rubber in the tire width direction is preferably located 3 mm or more inward in the tire width direction from the ground contact end. This is because the run-flat durability can be further improved. For the same reason, it is more preferable that the inner end of the side reinforcing rubber in the tire width direction is located 5 mm or more inward in the tire width direction from the ground contact end. On the other hand, from the viewpoint of suppressing the decrease in power receiving efficiency by the side reinforcing rubber hindering the magnetic flux, the inner end of the side reinforcing rubber in the tire width direction is located inside the tire width direction from the ground contact end within a range of 20 mm or less. Is preferable.
Here, the tire includes a pair of bead portions and a carcass straddling the pair of bead portions in a toroidal shape, and the side reinforcing rubber is arranged between the carcass and the inner surface of the tire in the tire width direction. preferable. As a result, the carcass can be protected by the side reinforcing rubber, and the trauma resistance of the tire can be improved.
Further, in the cross-sectional view in the tire width direction, the side reinforcing rubber preferably has a crescent-shaped cross section. This is because the side reinforcing rubber is suitable for running while taking over the load when the tire is punctured.

Further, as shown in FIG. 16, the sidewall portion 12 of the tire 10 is provided with the side reinforcing rubber 60, and in the above reference state, the inner end of the side reinforcing rubber 60 in the tire width direction is the position of the ground contact end E in the tire width direction. Alternatively, it is also preferable that the tire is located outside the ground contact end E in the tire width direction. As a result, when power is transmitted from the power transmission coil 41 to the power reception coil 31 via the ground plane, the magnetic flux can be prevented from being hindered by the side reinforcing rubber 60. According to this, it is possible to suppress a decrease in power receiving efficiency.
Here, the inner end of the side reinforcing rubber in the tire width direction is preferably located 3 mm or more outside the ground contact end in the tire width direction. This is because the decrease in power receiving efficiency can be further suppressed. For the same reason, it is more preferable that the inner end of the side reinforcing rubber in the tire width direction is located 5 mm or more outside the ground contact end in the tire width direction. On the other hand, from the viewpoint of improving the run-flat performance, the inner end of the side reinforcing rubber in the tire width direction is preferably located outside the ground contact end in the tire width direction within a range of 20 mm or less.
Here, the tire includes a pair of bead portions and a carcass straddling the pair of bead portions in a toroidal shape, and the side reinforcing rubber is arranged between the carcass and the inner surface of the tire in the tire width direction. preferable. As a result, the carcass can be protected by the side reinforcing rubber, and the trauma resistance of the tire can be improved.
Further, in the cross-sectional view in the tire width direction, the side reinforcing rubber preferably has a crescent-shaped cross section. This is because the side reinforcing rubber is suitable for running while taking over the load when the tire is punctured.

As a result of the study by the present inventor, it has been found that in a technique using the electromagnetic induction method, it is required to secure the power receiving efficiency not only during normal driving but also during run-flat driving.
Therefore, as shown in FIG. 15, a side reinforcing rubber 60 is provided on the sidewall portion 12 of the tire 10, and in the above reference state, the side reinforcing rubber 60 is provided in the tire width direction at the tire maximum width position in the tire radial direction. The width w is preferably 4 mm or more and 12 mm or less. If the width w is less than 4 mm, the load cannot be sufficiently supported on the shoulder during run-flat running, and the tire bends (for example, a state designed to maximize the power receiving efficiency with reference to normal running). The position of the power receiving coil 31 may be too close to the road surface, resulting in a decrease in power receiving efficiency. On the other hand, if the width w exceeds 12 mm, the magnetic flux may be hindered by the side reinforcing rubber and the power receiving efficiency may decrease during power supply during normal running. On the other hand, by setting the width w to 4 mm or more and 12 mm or less, it is possible to achieve both power receiving efficiency during normal running and run-flat running.
Here, in the above reference state, the width w of the side reinforcing rubber in the tire width direction at the tire radial position of the tire maximum width position is preferably 6 mm or more and 10 mm or less. By setting the width w to 6 mm or more, the load can be sufficiently supported on the shoulder during run-flat running, and fluctuations in the distance between the power receiving coil and the road surface (from normal running) are suppressed. It is possible to further suppress a decrease in power receiving efficiency during run-flat running. Further, by setting the width w to 10 mm or less, it is possible to prevent the magnetic flux from being further hindered by the side reinforcing rubber during power supply during normal traveling, and to further suppress a decrease in power receiving efficiency during normal traveling. For the same reason, the width w is more preferably 7 mm or more and 9 mm or less.
Here, the tire includes a pair of bead portions and a carcass straddling the pair of bead portions in a toroidal shape, and the side reinforcing rubber is arranged between the carcass and the inner surface of the tire in the tire width direction. preferable. As a result, the carcass can be protected by the side reinforcing rubber, and the trauma resistance of the tire can be improved.
Further, in the cross-sectional view in the tire width direction, the side reinforcing rubber preferably has a crescent-shaped cross section. This is because the side reinforcing rubber is suitable for running while taking over the load when the tire is punctured.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, in the present invention, the vehicle 2 has been described as being an automobile, but this is not the case. Vehicle 2 includes, in addition to automobiles such as passenger cars, trucks, buses, and two-wheeled vehicles, agricultural vehicles such as tractors, construction or construction vehicles such as dump trucks, electric bicycles, and power sources such as motors such as electric wheelchairs. It may include any vehicle that drives wheels and tires. Further, in addition to the one in which the vehicle itself is electrically driven, it may be used as a power source for using electric power in the vehicle.

Further, for example, in the present invention, the tire has been described as being filled with air, but the present invention is not limited to this. For example, the tire can be filled with a gas such as nitrogen. Further, for example, the tire can be filled with any fluid including not only gas but also liquid, gel-like substance, powder or granular material and the like.

Further, for example, in the present invention, the tire has been described as being a tubeless tire provided with an inner liner, but the present invention is not limited to this. For example, the tire may be a tube type tire provided with a tube.

Further, for example, in the present invention, the tire may be a non-pneumatic tire. In this case as well, the power receiving coil may be arranged at a position where it can face the power transmission coil.

In the present invention, it is particularly preferable to use a tire having a ground contact width of 120 mm or more.

1: Wireless power receiving system, 2: Vehicle,
2A: Hub, 2B: Drive shaft,
3: Tire / wheel assembly, 4: In-wheel motor,
10: Tire, 11: Bead part,
12: sidewall part, 13: tread part, 13a: tread,
14: Carcass, 14A: Carcass body, 14B: Carcass folded part,
15: Belt, 16: Inner liner,
17: Circumferential main groove, 19: Interlayer rubber,
20: Wheel, 21: Rim part,
22: Disc part, 22A: Mounting part, 22B: Spokes,
23: Flange, 24: Bead sheet, 25: Well,
26: Hump, 27: Valve, 28: Wheel cover,
30: Power receiving device, 31: Power receiving coil,
32: Power conversion circuit, 33: Power storage unit, 34: Control unit,
40: Power transmission device, 41: Power transmission coil,
60: Side reinforcement rubber

Claims (2)

With tires and wheels with rims
The tire is attached to the rim portion and is mounted on the rim portion.
The tire / wheel assembly includes a power receiving coil.
The tire includes a pair of bead portions and a carcass composed of one or more carcass plies straddling the pair of bead portions in a toroidal shape.
The tire / wheel assembly is characterized in that the carcass ply cord is inclined at an inclination angle of 80 ° or more with respect to the tire circumferential direction. A bead core is embedded in each of the pair of bead portions.
The carcass is composed of a carcass main body portion that straddles the pair of bead portions in a toroidal shape and a carcass winding portion that extends from the carcass main body portion and is wound up from the inside to the outside in the tire width direction of the bead core. The tire / wheel assembly according to claim 1, wherein the tire / wheel assembly has one or more upplies.

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