JP2021022624A - Tire/wheel assembly, wireless power receiving system, and tire - Google Patents

Abstract

To provide a tire/wheel assembly, a wireless power receiving system, and a tire capable of achieving high power receiving efficiency in automatic power feeding using an electromagnetic induction method.SOLUTION: In a tire-wheel assembly 3 with a tire 10 and a wheel 20 with a rim 21 in a wireless power receiving system 1, the tire is mounted on the rim, and a power receiving coil 31 is provided inside the tire/wheel assembly or on the rim. The tire is attached to the rim, specified internal pressure is filled, and when the area of a ground contact surface which is a surface that comes into contact with the road surface in a case in which the maximum load is applied is St (mm2), and a projected area is Sc (mm2) in a case in which the power receiving coil is positioned so as to maximize the projected area at the time of projecting the receiving coil onto the road surface by the receiving coil, the ratio Sc/St is more than 1.SELECTED DRAWING: Figure 1

Description

The present invention relates to a tire / wheel assembly, a wireless power receiving system, and a tire.

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 autonomous driving technology using an electric vehicle is proceeding because the response to vehicle operation is better when using an electric motor than when using an engine. Has been done. It has also been proposed that the electric motor be a so-called in-wheel motor that is housed inside the wheel of the tire / wheel assembly from the viewpoint of responsiveness to vehicle operation.

In an electric vehicle, it is possible to completely stop the vehicle at a service station or the like to supply power, but from the viewpoint of convenience of vehicle driving, etc., the vehicle is running (including when the vehicle is stopped at a traffic light, etc.). It is desirable that power is automatically supplied to the vehicle. When automatically supplying power to a vehicle using an in-wheel motor, it is preferable to supply power to a power receiving device housed inside the tire / wheel assembly from the viewpoint of energy efficiency of power supply. Here, as a method for automatically supplying electric power to a vehicle, an overhead wire method which is a wired method, an electromagnetic induction method which is a wireless method, an electric field coupling method, 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 (2) on the vehicle side. By passing through the next 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.

In automatic power supply using the electromagnetic induction method, it is required to achieve high power receiving efficiency.

An object of the present invention is to provide a tire / wheel assembly, a wireless power receiving system, and a tire 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.
The tire / wheel assembly of the present invention
With tires and wheels with rims
The tire is attached to the rim portion and is mounted on the rim portion.
A power receiving coil is provided inside the tire / wheel assembly or inside the rim portion.
The tire is mounted on the rim portion, the specified internal pressure is applied, and the area of the ground contact surface, which is the surface that comes into contact with the road surface when the maximum load is applied, is set to St (mm ² ), and the power receiving coil receives the power. When the projected area of the power receiving coil is positioned to be the maximum when the coil is projected onto the road surface, the ratio Sc / St is more than 1 when the projected area is Sc (mm ² ). It is a feature.
According to the tire / wheel assembly of the present invention, high power receiving efficiency can be achieved in automatic power feeding using the electromagnetic induction method.

Here, the "rim part" 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 Tire Rim Technical Organization) STANDARDS MANUAL, in the United States TRA (The Tire and Rim Association, Inc.) YEAR BOOK in YEAR BOOK, etc., or the size described in the future. In STANDARD S MANUAL, it means "Measuring Rim", and in TRA's YEAR BOOK, it means "Design Rim". Including. As an example of the "size described in the future", the size described as "FUTURE DEVELOPMENTS" in the ETRTO 2013 edition can be mentioned), but the size is not described in the above industrial standard. Refers to a rim having a width corresponding to the bead width of the tire.
In addition, the "specified internal pressure" 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 has a size not described in the above industrial standard. In this case, 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 maximum load capacity.

In the tire / wheel assembly of the present invention, the ratio Sc / St is preferably 1.1 or more and 2.0 or less.
Within the above range, high power receiving efficiency can be more reliably achieved while suppressing weight increase due to the power receiving coil.

In the tire / wheel assembly of the present invention, it is preferable that the power receiving coil is attached to the inner peripheral surface or the outer peripheral surface of the rim portion.
According to this configuration, the power receiving coil can be stably attached.

In the tire / wheel assembly of the present invention,
The rim portion has a well and has a well.
The power receiving coil is attached to the inner peripheral surface or the outer peripheral surface of the bottom of the well.
When the tire is mounted on the rim portion, the specified internal pressure is applied, a camber angle of -3 to 3 ° is applied, and the state in which the maximum load is applied is set as the camber applying load state.
The inner peripheral surface or the outer peripheral surface of the bottom of the well on the side to which the power receiving coil is attached in the camber-applied load state is a surface that is in contact with the road surface in the camber-applied load state. , Parallel, or tilted at an angle of -3 to 3 ° or less.
According to this configuration, when the power receiving coil is attached to the inner peripheral surface or the outer peripheral surface of the bottom of the well, the camber angle in the above range is given to the tire while suppressing the weight increase of the power receiving coil. The power receiving efficiency can be further improved.
The camber angle is defined as an angle with respect to a direction perpendicular to the ground plane. In addition, "+ (plus)" indicates that it is a positive camber, and "-(minus)" indicates that it is a negative camber. Further, the + (plus) and-(minus) angles of the inner peripheral surface or the outer peripheral surface of the bottom of the well are such that the inner peripheral surface or the outer peripheral surface of the bottom of the well becomes the ground contact surface when the camber angle is 0 °. The angle formed when a positive camber is applied to the inner peripheral surface or the outer peripheral surface that are parallel to each other is + (plus), and the angle formed when a negative camber is applied is − (minus).
Regarding the above "parallel" and "angle", when the inner peripheral surface and the outer peripheral surface of the bottom of the well are not straight in the cross-sectional view of the wheel, linear approximation is performed by the least squares method in the same cross-sectional view. Suppose you think.

In the tire / wheel assembly of the present invention,
The ground contact length of the ground contact surface in the tire circumferential direction is Lt (mm), and the ground contact width in the tire width direction is Wt (mm).
When the power receiving coil is positioned so that the projected length of the power receiving coil in the tire circumferential direction is maximized when the power receiving coil is projected onto the road surface, the projected length is defined as Lc (mm).
When the power receiving coil is positioned so that the projected width in the tire width direction of the power receiving coil is maximized when the power receiving coil is projected onto the road surface, the projected width is Wc (mm).
Lc> Lt and Wc> Wt
Is preferable.
According to this configuration, high power receiving efficiency can be more reliably achieved in automatic power supply using the electromagnetic induction method.

In the tire / wheel assembly of the present invention,
When the actual area of the power receiving coil is T (mm ² ),
The ratio Sc / T is preferably 0.5 or more.
By setting the above range, the amount of power received by the power receiving coil with respect to the weight of the power receiving coil can be increased.

In the tire / wheel assembly of the present invention,
A plurality of the power receiving coils are provided.
The maximum distance between the power receiving coils adjacent to the wheel in the circumferential direction along the circumferential direction is d (mm).
When the contact patch of the contact patch in the tire circumferential direction is Lt (mm),
d≤Lt
It is preferable to satisfy.
According to this configuration, it is possible to improve the power receiving efficiency when the tire rolls.

The wireless power receiving system of the present invention
With any of the above tire / wheel assemblies,
It is characterized by comprising a power receiving device for receiving electric power supplied by radio, which is housed in a housing portion radially inside the tire / wheel assembly with respect to the rim portion.
According to the wireless power feeding system of the present invention, high power receiving efficiency can be achieved in automatic power feeding using the electromagnetic induction method.

The tire of the present invention
It is characterized in that it is used for any of the above tire / wheel assemblies.
According to the tire of the present invention, high power receiving efficiency can be achieved in automatic power feeding using the electromagnetic induction method.

According to the present invention, it is possible to provide a tire / wheel assembly, a wireless power receiving system, and a tire 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 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 the wheel which concerns on one Embodiment of this invention. It is the schematic which shows the modification of the wireless power receiving system which concerns on one Embodiment of this invention by the cross section in the tire width direction. It is the figure which shows typically the ground contact length Lt (mm) and the projection length Lc (mm) of a power receiving coil when the tire is seen from the side. It is a tire width direction sectional view schematically showing a ground contact width Wt (mm) and a projection width Wc (mm) of a power receiving coil.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Wireless power receiving system>
FIG. 1 is a schematic view schematically showing a wireless power receiving system 1 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 schematic. The power transmission coil 41 included in the power transmission device 40 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 alternating magnetic field such as a coil spring or an air core coil can be applied. It can be any coil that can be generated.
As shown in FIG. 1, the wireless power receiving system 1 according to the embodiment of the present invention includes a tire / wheel assembly 3 and a power receiving device 30 that receives electric power supplied by radio. The power receiving device 30 is housed in an 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 and the power receiving device 30 will be described in order.

≪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, non-magnetic materials include paramagnetic materials and diamagnetic materials having 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 vinyl ester resin and 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 folded 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 folding portion 14B, or may have a structure in which the carcass folding 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 may be composed of 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 vinyl ester resin and 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. In the present embodiment, the carcass 14 has a radial structure, but the carcass 14 is not limited to this and may have a bias structure.

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, a plurality of belt layers laminated in the tire radial direction. In this 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 vinyl ester resin and 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 (not shown). 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. Further, in the present invention, the rubber or the side reinforcing rubber constituting the sidewall portion 12 may contain a magnetic material having a high magnetic permeability (for example, a ferromagnetic material) such as 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 sidewall portion 12 in the tire width direction, and thus the power receiving efficiency can be improved. Can be improved.

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

In each of the above examples, 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 to the outer diameter OD is 0.26 or less. Yes, when the cross-sectional width SW of the tire 10 is 165 (mm) or more, the cross-sectional width SW (mm) and the outer diameter OD (mm) of the tire 10 are
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 above 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 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, 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). ..

In each of the above examples, the tire 10 preferably satisfies the ratio SW / OD and / or the relational expression (2) when the internal pressure is 250 kPa or more, or the relational expression (1) and / Alternatively, it is preferable to satisfy the relational expression (2).

In each of the above examples, the tire 10 is preferably used at an internal pressure of 250 kPa or more. In this case, in particular, the tire 10 satisfies the ratio SW / OD and / or the relational expression (2) when the internal pressure is 250 kPa or more, or the relational expression (1) and / or the relational expression (2). ) Is satisfied. As a result, both the rolling resistance value of the tire and the weight of the tire can be reduced. Therefore, both power feeding efficiency and fuel efficiency can be suitably achieved.

In each of the above examples, 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 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 low as compared with 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. It is possible to suppress a decrease in ride comfort by preventing the vertical spring constant from becoming too large.
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.

In each of the above examples, when the width of the bead filler 11B in the tire width direction 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 secured, the lateral spring constant can be maintained, and the steering stability can be further secured.

In each of the above examples, 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 secured, the lateral spring constant can be maintained, and the steering stability can be further secured.
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 in the tire maximum width portion (measured in this cross section in the normal direction of the tangent line at a point on the tire surface in the tire maximum width portion) 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 portion" refers to the maximum width position in the cross section in the tire width direction when the tire is mounted on the rim and is in a no-load 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 in the maximum width portion of the tire having a large bending deformation under a tire load, reduce the longitudinal spring coefficient, and improve the riding comfort. ..
That is, if the ratio Ts / Tb exceeds 60%, the gauge of the sidewall portion 12 in the maximum tire width portion 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 width portion of the tire 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 in the maximum tire width portion, 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 the Tbc to 3 mm or more, it is possible to realize weight reduction while ensuring the flexural rigidity and torsional rigidity on the rim flange, while by setting the Tbc to 16 mm or less, the weight increase can be suppressed. , Steering stability can be ensured.
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 and the outermost end 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 power supply efficiency and 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, both power supply efficiency and fuel efficiency can be suitably achieved.

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, both power supply efficiency and fuel efficiency can be suitably achieved.

In each of the above examples, it is preferable that the ratio Ts / Tc of the gauge Ts of the sidewall portion 12 in the maximum width portion of the tire to the diameter Tc of the carcass cord 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 in the maximum width portion of the tire having a large bending deformation under a tire load, reduce the longitudinal spring coefficient, and improve the riding comfort. ..
That is, by setting the ratio Ts / Tc to 12 or less, the gauge of the sidewall portion 4 in the maximum tire width portion 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 does not decrease 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 in the maximum width portion 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 in the maximum tire width portion is reduced, the rigidity of the sidewall portion 12 is reduced, the longitudinal 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 in the tire maximum width portion.
That is, when the carcass folded portion 14B extends radially outward from the maximum tire width portion, the distance in the tire width direction from the surface of the carcass cord 14c of the portion forming the carcass folded portion 14B to the outer surface of the tire is set to 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 Tc to 0.8 mm or less, the vertical spring coefficient can be reduced and riding comfort can be improved. On the other hand, by setting Tc to 0.4 mm or more, the lateral spring coefficient can be increased for maneuvering. Stability can be ensured.

(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 attached to 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 in the radial direction of the wheel 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 vinyl ester resin and 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 cavity 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 above-mentioned non-magnetic material, 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 an accommodating portion 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 device≫
≪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 inner peripheral surface of the bottom of the well 25, and four power receiving coils 31 are arranged at equal intervals (interval d (mm)) on the circumference. Has been done. 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 and current flows to supply power. 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 outer 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 or 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, and the power receiving coil 31 can be configured to rotate 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 and 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 non-magnetic material, the belt cord is made of the above non-magnetic material, and the rim portion 21 of the wheel 20 is made of the above non-magnetic material, which suppresses the decrease in power receiving efficiency. It is preferable from the viewpoint of

FIG. 4 is a schematic view schematically showing a modified example of the wireless power receiving system according to the embodiment of the present invention with a cross section in the tire width direction.
As shown in FIG. 4, the power receiving device 30 can be attached to the tire 10 or the wheel 20 so as not to 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.

Here, in the present embodiment, the area of the ground contact surface, which is the surface that comes into contact with the road surface when the tire 10 is mounted on the rim portion 21, the specified internal pressure is applied, and the maximum load is applied, is set to St (mm ² ). When the power receiving coil 31 is positioned so that the projected area of the power receiving coil is maximized when the power receiving coil 31 is projected onto the road surface, the ratio Sc / when the projected area is Sc (mm ² ). St is more than 1 (in this embodiment, the ratio Sc / St is 1.1 or more and 2.0 or less). In this embodiment, the camber angle is set to 0 °.

FIG. 5A is a view when the tire is viewed from the side, schematically showing the ground contact length Lt (mm) and the projected length Lc (mm) of the power receiving coil. FIG. 5B is a cross-sectional view in the tire width direction schematically showing the ground contact width Wt (mm) and the projected width Wc (mm) of the power receiving coil. In FIG. 5A, only one of the power receiving coils 31 arranged at four locations on the periphery is shown. In FIG. 5B, a cross-sectional view in the tire width direction is shown through a portion where one power receiving coil 31 is located. In this example, the power receiving coil 31 has a curvature (not necessarily the same as the curvature of the wheel) corresponding to the curvature of the wheel 20 in the side view of FIG. 5A. In the side view shown in FIG. 5A, the actual periferi length of the power receiving coil 31 and the projected length of the power receiving coil 31 when projected onto the road surface are different (the actual periferi length of the power receiving coil 31 is longer than the projected length). .. On the other hand, in the cross-sectional view shown in FIG. 5B, the actual periferi width of the power receiving coil 31 and the projected width of the power receiving coil when projected onto the road surface are equal. On the other hand, in the present invention, the power receiving coil 31 may be configured to have no curvature in the side view of FIG. 5A. In this case, the actual periferi length (width) of the power receiving coil 31 is the projected length (width). Width). Further, in the present invention, the power receiving coil 31 may be configured to have a curvature in the cross-sectional view of FIG. 5B. In this case, the actual periferi length (width) of the power receiving coil 31 is the projected length (width). Become larger.
When the power receiving coil 31 is configured to rotate together with the tire 10 and the wheel 20 as in the present embodiment, when the power receiving coil 31 is projected onto the road surface within one rotation during the tire rolling. There is a timing at which the power receiving coil 31 is positioned so as to maximize the projected area.
For example, in order to stop on the power transmission device 41 at such a timing, automatic driving technology can be used, or a sensor for detecting the rotational state of the tire is provided in the tire 10 and the sensor is detected. The rotation information can be notified to the driver by a communication unit or the like, and the driver can stop the vehicle.
On the other hand, when the power receiving coil 31 is configured to be non-rotating with respect to the rotation of the tire 10 or the wheel 20, the power receiving coil 31 projects the power receiving coil 31 onto the road surface in advance. It can be positioned so that the projected area of the coil 31 is maximized.
As shown in FIGS. 5A and 5B, the ground contact length of the ground contact surface in the tire circumferential direction is Lt (mm), the ground contact width in the tire width direction is Wt (mm), and the power receiving coil 31 uses the power receiving coil 31. When the power receiving coil 31 is positioned so as to maximize the projected length in the tire circumferential direction when projected onto the road surface, the projected length is Lc (mm), and the power receiving coil 31 makes the power receiving coil 31 the road surface. When the projected width in the tire width direction of the power receiving coil 31 is set to the maximum when projected onto the tire, the projected width is Wc (mm).
Lc> Lt and Wc> Wt
Is.

Hereinafter, the operation and effect of the wireless power receiving system 1 according to the present embodiment will be described.
When the power receiving device 30 receives power wirelessly from the power transmitting device 40 provided on a road or the like, an obstacle enters the space between the power receiving device 30 and the power transmitting device 40, so that the surroundings of the obstacle An eddy current may be generated in the power transmission, which may reduce the power receiving efficiency.
On the other hand, among the magnetic fluxes emitted from the power transmission coil 41, the magnetic flux passing through the ground contact surface of the tire is not hindered by such obstacles, so that the power receiving efficiency of the magnetic flux passing through the ground contact surface of the tire is improved. Is efficient.
In the wireless power feeding system 1 of the present embodiment, since the ratio Sc / St is more than 1, all of the magnetic flux passing through the ground plane can be received by the power receiving coil 31. As a result, the power receiving efficiency of the power receiving coil 31 can be maximized and high power receiving efficiency can be achieved.
In particular, in the present embodiment, since the ratio Sc / St is 1.1 or more, high power receiving efficiency can be more reliably achieved. Further, in the present embodiment, since the ratio Sc / St is 2.0 or less, it is possible to suppress the weight increase due to the power receiving coil.
Further, in the present embodiment, since Lc> Lt and Wc> Wt, the power receiving efficiency of the power receiving coil 31 is maximized in both the tire circumferential direction and the tire width direction, and automatic power feeding using the electromagnetic induction method is used. In, high power receiving efficiency can be achieved more reliably.
Further, in particular, in the present embodiment, the power receiving coil 31 is attached to the inner peripheral surface or the outer peripheral surface (inner peripheral surface in the present embodiment) of the rim portion 21 (the bottom portion of the well 25 in the present embodiment). As a result, the power receiving coil 31 can be stably attached.
As described above, according to the wireless power feeding system 1 of the present embodiment, high power receiving efficiency can be achieved in the automatic power feeding using the electromagnetic induction method.

Similarly, according to the tire / wheel assembly 3, for example, by using it in the wireless power feeding system, high power receiving efficiency can be achieved in automatic power feeding using the electromagnetic induction method.

In the tire / wheel assembly of the present invention, the ratio Sc / St is preferably 1.1 or more and 2.0 or less. This is because, as described above, high power receiving efficiency can be more reliably achieved while suppressing the weight increase due to the power receiving coil. For the same reason, the ratio St / Sc is more preferably 1.2 or more and 1.9 or less.
Similarly, in the wireless power receiving system of the present invention, the ratio St / Sc is preferably 1.1 or more and 2.0 or less, and more preferably 1.2 or more and 1.9 or less.

In the tire / wheel assembly of the present invention, the rim portion has a well, and the power receiving coil is attached to the inner peripheral surface or the outer peripheral surface of the bottom portion of the well, and the tire is attached to the rim portion to fill the specified internal pressure. Then, when a camber angle of -3 to 3 ° is applied and the state in which the maximum load is applied is set to the camber applying load state, the inside of the bottom of the well on the side where the power receiving coil is attached in the camber applying load state. It is preferable that the peripheral surface or the outer peripheral surface is parallel to the ground contact surface, which is the surface that comes into contact with the road surface in the camber-applied load state, or is inclined at an angle of -3 to 3 °.
When the power receiving coil is attached to the inner peripheral surface or the outer peripheral surface of the bottom of the well, the projected area on the ground plane can be made larger than the actual area of the power receiving coil. This is because the power receiving efficiency when the tire is provided with the camber angle in the above range can be further improved while suppressing the weight increase of the power receiving coil.
Similarly, in the wireless power receiving system of the present invention, the rim portion has a well, and the power receiving coil is attached to the inner peripheral surface or the outer peripheral surface of the bottom of the well, and the tire is attached to the rim portion to apply a specified internal pressure. When the tire is filled and a camber angle of -3 to 3 ° is applied to make the state in which the maximum load is applied the camber-applied load state, the bottom of the well on the side where the power receiving coil is attached in the camber-applied load state. It is preferable that the inner peripheral surface or the outer peripheral surface is parallel to the ground contact surface, which is the surface that comes into contact with the road surface in the camber-applied load state, or is inclined at an angle of -3 to 3 °.

In the tire / wheel assembly of the present invention,
Lc> Lt and Wc> Wt
Is preferable.
This is because the power receiving efficiency of the power receiving coil can be maximized in both the tire circumferential direction and the tire width direction, and high power receiving efficiency can be more reliably achieved in the automatic power supply using the electromagnetic induction method.
Similarly, in the wireless power receiving system of the present invention,
Lc> Lt and Wc> Wt
Is preferable.

In the tire / wheel assembly of the present invention,
When the actual area of the power receiving coil (the area surrounded by the outer circumference of the power receiving coil) is T (mm ² ),
The ratio Sc / T is preferably 0.5 or more.
This is because the power receiving amount of the power receiving coil can be increased with respect to the weight of the power receiving coil by setting the above range.
For the same reason, the ratio Sc / T is more preferably 0.7 or more.
Similarly, in the wireless power receiving system of the present invention, the ratio Sc / T is preferably 0.5 or more, and more preferably 0.7 or more.

In the tire / wheel assembly of the present invention,
Equipped with multiple power receiving coils
Of the distances (minimum distances) along the circumferential direction between the power receiving coils adjacent to each other in the circumferential direction of the wheel, the maximum distance is d (mm).
When the contact patch of the contact patch in the tire circumferential direction is Lt (mm),
d≤Lt
It is preferable to satisfy.
According to this configuration, power is always supplied when the tire rolls (when the tire is located on the power transmission coil), and the power receiving efficiency when the tire rolls can be improved.
Similarly, in the wireless power receiving system of the present invention,
d≤Lt
It is preferable to satisfy.

When a plurality of power receiving coils are provided, it is preferable that the intervals between the power receiving coils adjacent to each other in the circumferential direction of the wheel along the circumferential direction are equal intervals from the viewpoint of uniformity.

<Tire>
The tire according to the embodiment of the present invention is used for the above-mentioned tire / wheel assembly. The tire according to the embodiment of the present invention is made of a non-magnetic material at least one (preferably all) of the bead wire, the carcass cord, and the belt cord used for the bead core.
According to the tire of the present embodiment, high power receiving efficiency can be achieved in automatic power feeding using an electromagnetic induction method by using it as a tire portion of the tire / wheel assembly, for example, in the wireless power feeding system. it can.

<Wireless power supply system>
This wireless power supply system includes the above-mentioned wireless power receiving system and a power transmission device. According to this wireless power feeding system, high power receiving efficiency can be achieved in automatic power feeding using the electromagnetic induction method.

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 automobiles such as passenger cars, trucks, buses, and two-wheeled vehicles, as well as power sources such as agricultural vehicles such as tractors, construction or construction vehicles such as dump trucks, electric bicycles, and 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 supply 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 that the tire has a ground contact width (the width of the ground contact surface in the tire width direction between both ends in the tire width direction) of 250 mm or less.

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, 14: Carcass, 14A: Carcass body part, 14B: Carcass folded part, 15: Belt, 16: Inner liner, 20: Wheel, 21: Rim part, 22: Disc part, 22A: Mounting part, 22B: Spokes , 23: Flange, 24: Bead-seat, 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: Transmission device, 41: Transmission coil

Claims (9)

A tire-wheel assembly comprising a tire and a wheel having a rim portion.
The tire is attached to the rim portion and is mounted on the rim portion.
A power receiving coil is provided inside the tire / wheel assembly or inside the rim portion.
The tire is mounted on the rim portion, the specified internal pressure is applied, and the area of the ground contact surface, which is the surface that comes into contact with the road surface when the maximum load is applied, is St (mm ² ), and the power receiving coil receives the power. When the projected area of the power receiving coil is located so as to be the maximum when the coil is projected on the road surface, the ratio Sc / St is more than 1 when the projected area is Sc (mm ² ). A characteristic tire / wheel assembly. The tire / wheel assembly according to claim 1, wherein the ratio Sc / St is 1.1 or more and 2.0 or less. The tire / wheel assembly according to claim 1 or 2, wherein the power receiving coil is attached to an inner peripheral surface or an outer peripheral surface of the rim portion. The rim portion has a well and has a well.
The power receiving coil is attached to the inner peripheral surface or the outer peripheral surface of the bottom of the well.
When the tire is mounted on the rim portion, the specified internal pressure is applied, a camber angle of an angle of -3 to 3 ° is applied, and the state in which the maximum load is applied is defined as a camber applying load state.
The inner peripheral surface or the outer peripheral surface of the bottom of the well on the side to which the power receiving coil is attached in the camber-applied load state is a surface that is in contact with the road surface in the camber-applied load state. The tire / wheel assembly according to any one of claims 1 to 3, which is parallel or inclined at an angle of -3 to 3 °. The ground contact length of the ground contact surface in the tire circumferential direction is Lt (mm), and the ground contact width in the tire width direction is Wt (mm).
When the power receiving coil is positioned so that the projected length of the power receiving coil in the tire circumferential direction is maximized when the power receiving coil is projected onto the road surface, the projected length is defined as Lc (mm).
When the power receiving coil is positioned so that the projected width in the tire width direction of the power receiving coil is maximized when the power receiving coil is projected onto the road surface, the projected width is Wc (mm).
Lt <Lc and Wt <Wc
The tire / wheel assembly according to any one of claims 1 to 4. When the actual area of the power receiving coil is T (mm ² ),
The tire / wheel assembly according to any one of claims 1 to 5, wherein the ratio Sc / T is 0.5 or more. A plurality of the power receiving coils are provided.
The maximum distance between the power receiving coils adjacent to the wheel in the circumferential direction along the circumferential direction is d (mm).
When the contact patch of the contact patch in the tire circumferential direction is Lt (mm),
d≤Lt
The tire / wheel assembly according to any one of claims 1 to 6, which satisfies the above conditions. The tire / wheel assembly according to any one of claims 1 to 7.
A wireless power receiving system comprising a power receiving device for receiving electric power supplied by radio, which is housed in a housing portion radially inside the tire / wheel assembly with respect to the rim portion. A tire, which is used for the tire / wheel assembly according to any one of claims 1 to 7.

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