Tire and wireless power supply system

Abstract

To provide a tire which is excellent in durability of a power incoming coil, and a wireless power supply system using the tire.SOLUTION: A tire 10 comprises: a tread part D provided with a belt 20;: a bead part A provided with a toric bead core 14; a pair of side wall parts B provided between the tread part D and the bead part A; and a power incoming coil 40 which receives electric power supplied by an AC magnetic field from the exterior of the tire 10. The power incoming coil 40 has a loop coil part 42 comprising a loop coil, and a drawing part 43 which connects the loop coil part 42 and an electronic circuit board 46, and the loop coil part 42 is located in a side area MS. The drawing part 43 and a belt adjacent area MS cross each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tire and a wireless power supply system. [Background technology]

[0002] Conventionally, a wireless power receiving system has been proposed that supplies power between a power transmitting coil provided in a vehicle body and a power receiving coil attached to a tire. The power receiving coil is provided, for example, along the tire cavity surface facing the tire cavity region (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-29235 Summary of the Invention [Problem to be solved by the invention]

[0004] In such a wireless power receiving system, the power receiving coil provided in the tire is deformed repeatedly together with the tire, and therefore is desired to have excellent durability.

[0005] An object of the present invention is to provide a tire having a power receiving coil with excellent durability and a wireless power supply system using the tire. [Means for solving the problem]

[0006] The tire of the present invention includes a tread portion provided with a belt, a bead portion provided with annular bead cores, a pair of sidewall portions provided between the tread portion and the bead portion, and a power receiving coil that receives power supplied by an AC magnetic field from outside the tire, the power receiving coil has a loop coil portion formed of a loop coil and a lead-out portion connecting the loop coil portion to an electronic circuit board, The loop coil portion is disposed in a side region, the side region is a region in a meridian cross section of the tire between a first perpendicular line drawn from an outer end of the bead core in the tire radial direction to a tire cavity surface in a normal direction of the tire cavity surface, and a second perpendicular line drawn from an outer end of the belt in the tire width direction to the tire cavity surface in a normal direction of the tire cavity surface, The pull-out portion and the belt adjacent region intersect, When the tire cross-sectional height is SH, the belt-adjacent region is an annular region whose outer edge is the position where a second perpendicular line drawn from the tire width direction side end of the belt in the normal direction to the tire cavity surface intersects with the tire cavity surface, and whose inner edge is a position spaced from the second perpendicular line along the tire cavity surface toward the bead portion by a length Fx expressed by the following formula (1): Fx = 0.12 × SH (1) [Effects of the Invention]

[0007] The tire and wireless power supply system according to the present invention have excellent durability of the power receiving coil. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a portion on one side in the tire width direction with respect to the tire equatorial plane in a tire meridian cross section of the contact patch side of a tire according to this embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the positional relationship between the power receiving coil and the fixing member according to this embodiment, as viewed from the inner side in the tire width direction. [Figure 3] FIG. 3 is a schematic diagram showing the tire cavity surface of the tire according to this embodiment, as viewed from the inner side in the tire width direction. [Figure 4] FIG. 4 is a schematic diagram showing the tire cavity surface of the tire according to this embodiment, as viewed from the inner side in the tire radial direction. [Figure 5] FIG. 5 is a schematic diagram showing the tire cavity surface of the tire according to this embodiment, as viewed from the inner side in the tire width direction. [Figure 6]FIG. 6 is a schematic diagram showing the tire cavity surface of a tire according to a modified example (1) of the present embodiment, as viewed from the inner side in the tire width direction. [Figure 7] FIG. 7 is a schematic diagram showing the tire cavity surface of a tire according to a modified example (2) of the present embodiment, as viewed from the inner side in the tire width direction. [Figure 8] FIG. 8 is a schematic diagram showing the tire cavity surface of a tire according to a modified example (3) of the present embodiment, as viewed from the inner side in the tire width direction. [Figure 9] FIG. 9 is a schematic diagram showing the tire cavity surface of a tire according to a modified example (4) of this embodiment, as viewed from the inner side in the tire width direction. [Figure 10] FIG. 10 is a diagram showing a wireless power supply system according to this embodiment, illustrating a power transmitting coil and a tire in which a power receiving coil is provided (a portion on one side in the tire width direction relative to the tire equatorial plane in a tire meridian cross section on the non-ground contact side). [Figure 11] Figure 11 is a diagram showing that the receiving coil is located within the power supply area of ​​the transmitting coil in the wireless power supply system according to this embodiment, where (A) and (B) show an example in which the power supply direction is the tire width direction, and (C) and (D) show an example in which the power supply direction is inclined relative to the tire width direction. [Figure 12] FIG. 12 is a diagram showing the installation position of the power transmitting coil in the wireless power supply system according to this embodiment. [Figure 13] FIG. 13 is a partial meridional cross-sectional view showing the installation positions of the power transmitting coil and the power receiving coil in the wireless power supply system according to this embodiment. [Figure 14] Figure 14 shows an arrangement of receiving coils (an arrangement in which the receiving coils are not continuous in the tire circumferential direction, unlike in Figure 1), where (A) to (F) are examples showing receiving coils 40 consisting of 2, 3, 4, 5, 6, and 8 loop coil sections 40a, respectively, (G) is an example in which multiple loop coil sections 40a are stacked in the tire radial direction, and (H) is an example in which some of the multiple loop coil sections extend at an angle relative to the tire radial direction. DETAILED DESCRIPTION OF THE INVENTION

[0009] The embodiments of the present invention relate to the following aspects.

[0010] [Aspect 1] A tire comprising a tread portion provided with a belt, bead portions provided with annular bead cores, a pair of sidewall portions provided between the tread portion and the bead portions, and a power receiving coil that receives power supplied by an AC magnetic field from outside the tire, the power receiving coil has a loop coil portion formed of a loop coil and a lead-out portion connecting the loop coil portion to an electronic circuit board, The loop coil portion is disposed in a side region, the side region is a region in a meridian cross section of the tire between a first perpendicular line drawn from an outer end of the bead core in the tire radial direction to a tire cavity surface in a normal direction of the tire cavity surface, and a second perpendicular line drawn from an outer end of the belt in the tire width direction to the tire cavity surface in a normal direction of the tire cavity surface, The pull-out portion and the belt adjacent region intersect, When the tire cross-sectional height is SH, the belt-adjacent region is an annular region whose outer edge is a position where a second perpendicular line drawn from a side end of the belt in the tire width direction in a direction normal to the tire cavity surface intersects with the tire cavity surface, and whose inner edge is a position spaced apart from the second perpendicular line along the tire cavity surface toward the bead portion by a length Fx expressed by the following formula (1): Fx = 0.12 × SH (1)

[0011] [Aspect 2] The tire according to aspect 1, wherein a distance W in the tire width direction between a base end of the pull-out portion connected to the loop coil portion and a tip end intersecting an outer edge of the electronic circuit board, and a tire cross-sectional height SH satisfy the following formula (2): 0.1≦W / SH≦1.0 (2)

[0012] [Aspect 3] The tire according to aspect 2, wherein a distance L1 in the tire circumferential direction when a base end of the pull-out portion connected to the loop coil portion and a tip end intersecting an outer edge of the electronic circuit board are projected onto the loop coil portion, and a length LC in the tire circumferential direction of the tread portion satisfy the following formula (3): 0.002≦L1 / LC≦0.030 (3)

[0013] [Aspect 4] The tire according to aspect 3, wherein a distance L2 in the tire circumferential direction between an intersection of an outer edge of the belt-adjacent region and the pull-out portion and a point obtained by projecting the intersection of an inner edge of the belt-adjacent region and the pull-out portion onto the outer edge of the belt-adjacent region, and the length Fx satisfy the following formula (4): 0.25≦L2 / Fx≦4.00 (4)

[0014] [Aspect 5] The tire according to any one of aspects 1 to 4, wherein a distance L3 in the tire circumferential direction between points obtained by projecting a midpoint between a pair of base ends of the pull-out portion connected to the loop coil portion and a midpoint between a pair of tip ends at a position intersecting with the outer edge of the electronic circuit board onto an imaginary line extending in the tire circumferential direction and passing through the outer edge of the electronic circuit board, and a distance W in the tire width direction satisfy the relationship of the following formula (5): 0.25≦L3 / W≦4.00 (5) [Aspect 6] The tire according to any one of aspects 1 to 5, wherein a tire thickness Ga at an outer edge where the pull-out portions of the electronic circuit board installed on the tire cavity surface intersect, and a tire thickness Gb at an inner edge of the belt-adjacent region satisfy the following formula (6): 0.30≦Gb / Ga≦0.80 (6)

[0015] [Aspect 7] A tire according to aspect 4, wherein a maximum contact width H of the tread portion, a contact length S8 at a position that is 80% of the maximum contact width, and a contact length S9 at a position that is 90% of the maximum contact width satisfy the following formula (7): 0.025≦(|S8-S9|) / H≦0.400···(7)

[0016] [Aspect 8] A tire according to aspect 4, wherein the belt includes a steel cord, and an angle θ formed between the steel cord and a conductor of the pull-out portion in a region overlapping with the pull-out portion is 55° or less.

[0017] [Aspect 9] A tire according to any one of aspects 1 to 8, further comprising a reinforcing layer for suppressing deformation of the pulled-out portion on the outer side in the tire width direction at a location where the belt has only one layer.

[0018] [Aspect 10] A tire according to any one of aspects 1 to 9, further comprising a second additional reinforcing layer on the outer side of the belt in the tire width direction, the second additional reinforcing layer suppressing deformation of the pull-out portion.

[0019] [Aspect 11] The tire according to any one of aspects 1 to 10, mounted on a genuine rim.

[0020] [Aspect 12] 12. A wireless power supply system that applies AC power to a power transmitting coil that forms a resonant circuit with a capacitor and a coil, and transmits the power to the power receiving coil that also forms a resonant circuit with a capacitor and a coil, the wireless power supply system including the tire according to any one of aspects 1 to 11.

[0021] [Aspect 13] 13. The wireless power transfer system according to claim 12, wherein at least a portion of the power receiving coil is located within a power transfer region extending in a winding axis direction of the power transmitting coil across both longitudinal ends of the power transmitting coil in a tire meridian cross section.

[0022] [Aspect 14] A wireless power transfer system according to aspect 12 or 13, wherein a power transmission side surface of the power transmission coil unit including the power transmission coil that faces the power receiving coil forms an angle with the tire radial direction as viewed from the tire meridian cross section within a range of 70° toward the tire and 30° toward the tire away from the tire, with the inner end of the power transmission coil unit in the tire radial direction as the center.

[0023] [Aspect 15] 15. The wireless power supply system according to any one of aspects 12 to 14, wherein the power transmitting coils are installed within a range of 60° on both sides in the tire circumferential direction, centered on an imaginary line extending vertically upward from the center of the tire.

[0024] 1. Tires (Tire composition) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the tire radial direction refers to a direction perpendicular to the tire rotational axis, the tire radially inner side refers to the side toward the tire rotational axis in the tire radial direction, and the tire radially outer side refers to the side away from the tire rotational axis in the tire radial direction. The tire circumferential direction refers to the direction around the tire rotational axis as the central axis. Furthermore, the tire width direction refers to a direction parallel to the tire rotational axis, the tire widthwise inner side refers to the side toward the tire equatorial plane (tire equator line) in the tire width direction, and the tire widthwise outer side refers to the side away from the tire equatorial plane in the tire width direction. The tire equatorial plane refers to a plane that is perpendicular to the tire rotational axis and passes through the center of the tire width. Furthermore, the term "direction along" is not limited to being parallel to a certain reference point, but also includes being along a direction within a range of less than ±15° from the certain reference point.

[0025] Similarly, in the following description, a regular rim refers to an "applicable rim" as defined by JATMA, a "design rim" as defined by TRA, or a "measuring rim" as defined by ETRTO.

[0026] Similarly, in the following explanation, "normal internal pressure" refers to the "maximum air pressure" specified by JATMA, the maximum value specified in "Tire Load Limits at Various Cold Inflation Pressures" specified by TRA, or the "Inflation Pressures" specified by ETRTO. Also, "normal load" refers to the "maximum load capacity" specified by JATMA, the maximum value specified in "Tire Load Limits at Various Cold Inflation Pressures" specified by TRA, or the "Load Capacity" specified by ETRTO.

[0027] 1 is a diagram showing a portion on one side in the tire width direction with the tire equatorial plane CP as the reference in a tire meridian cross section of the contact patch side of a tire 10 according to this embodiment. Note that the drawing shows the tire portion on the contact patch side in a state where the tire is mounted on a rim and has a normal internal pressure applied, and is in an unloaded state.

[0028] As shown in Fig. 1, a tire 10 according to this embodiment includes a tire main body 11 and a power receiving coil 40. The tire main body 11 has, from the inner side to the outer side in the tire radial direction, a bead portion A, a sidewall portion B, a shoulder portion C, and a tread portion D. An inner liner 12 exposed to a tire cavity surface 13 is provided in the region from the bead portion A to the tread portion D, and a carcass 18 including a main portion 18a extending along the inner liner 12 and a folded portion 18b folded back around a bead core 14 and a bead filler 16 is provided on the opposite side from the tire cavity surface 13, and a belt 20 (belt layers 20a, 20b) is provided on the outer side in the tire radial direction of the carcass 18 in the tread portion D.

[0029] In the tire 10 configured as described above, the inner liner 12 is a layer for blocking gas coming into contact with the tire cavity surface 13. The inner liner 12 can be configured with a single inner liner layer, or can be configured with multiple inner liner layers laminated in the tire radial direction at the tire equatorial plane CP. The inner liner 12 includes at least one layer made of rubber or resin with low air permeability, and can include an adhesive layer at least in the portion in contact with the carcass 18 as other layers.

[0030] The bead core 14 is, for example, a ring-shaped reinforcing material made of bundled cords, and may have a structure in which a plurality of bead wires made of steel cords or organic fiber cords are covered with rubber. The bead filler 16 is a member for increasing the rigidity of the bead portion A, and may have a substantially inverted triangular shape as shown in Fig. 1, in which the tire width direction dimension at the tire radially inner end is substantially equal to the tire width direction dimension at the tire radially outer end of the bead core 14, and the tire width direction dimension gradually decreases toward the tire radially outer side.

[0031] The carcass 18 is a component that forms the framework of the tire 10 and is composed of at least one carcass layer (carcass ply), and each carcass layer is configured with a plurality of carcass cords coated with rubber. Generally, steel cords or organic fiber cords are used as the carcass cords. However, in the tire 10 according to this embodiment, as described below, it is preferable to use a non-magnetic material for the carcass cords in order to prevent a metal member from interfering with the magnetic field that is generated in the sidewall portion B so as to penetrate the tire cavity surface 13 of the inner liner 12 substantially perpendicularly. For example, organic fibers such as rayon, polyester, polyamide, and aramid can be used as the non-magnetic material.

[0032] The belt 20 is a reinforcing layer provided on the radially outer side of the carcass 18, and is a member that tightens the carcass 18 to increase the rigidity of the tread portion D, improves steering stability, and reduces strain deformation and rolling resistance. The belt 20 can be composed of multiple belt layers (two belt layers 20a, 20b in the example shown in FIG. 1) stacked in the radial direction of the tire in the tread portion D. Each of the belt layers 20a, 20b has a configuration in which multiple belt cords are covered with rubber. Generally, steel cords or organic fiber cords are used as the belt cords. As the belt cords, magnetic materials such as steel cords can of course be used, but non-magnetic materials (including paramagnetic materials and diamagnetic materials) can also be used.

[0033] The side tread 26 is arranged to connect the bead portion A and the tread portion D. The cap tread 30 is formed on a tread surface 34, which is the surface of the tread portion D, over the entire tire contact area. Both the side tread 26 and the cap tread 30 can use conventional rubber materials depending on the required characteristics of each.

[0034] The tire 10 according to this embodiment includes a power receiving coil 40 on the inner side in the tire width direction of the tire cavity surface 13, which receives AC power transmitted from a power transmitting coil (not shown) installed outside the tire 10. The power receiving coil 40 is fixed to the tire cavity surface 13 by a fixing member 41.

[0035] The power receiving coil 40 is formed of a conductor wire, for example, an electric wire made of copper, aluminum, or iron. The diameter of the conductor wire is preferably 0.5 to 1.2 mm. The conductor wire may be a solid wire or a stranded wire. In the present embodiment, the conductor wire is a solid wire. As shown in FIG. 2, the power receiving coil 40 has a loop coil portion 42 and a lead-out portion 43. In the loop coil portion 42, the conductor wire is wound around the tire rotation axis so as to be aligned in the tire circumferential direction along the tire cavity surface 13 corresponding to the tread portion D. The number of turns of the conductor wire in the loop coil portion 42 is preferably 1 to 5. The number of turns of the loop coil portion 42 shown in FIG. 2 is 1. The number of turns of the loop coil portion 42 is not limited to one or more complete turns in which both ends of the conductor wire cross each other, and the both ends of the conductor wire do not have to cross each other as shown in FIG. 2. The distance d1 between the two ends of the conductor when the two ends of the conductor do not intersect is not particularly limited, and may be, for example, 0.3% or more and 5.0% or less of the circumferential length of the loop coil portion 42, preferably 0.5% or more and 4.0% or less.

[0036] The loop coil portion 42 is preferably provided in a side region MS (FIG. 1) on the tire cavity surface 13. The side region MS refers to the region sandwiched between a first perpendicular line VT1 and a second perpendicular line VT2. The first perpendicular line VT1 is a perpendicular line extending from the tire radially outer end of the bead core 14 to the tire cavity surface 13 in a direction normal to the tire cavity surface 13. The second perpendicular line VT2 is a perpendicular line extending from the tire widthwise outer end of the belt 20 to the tire cavity surface 13 in a direction normal to the tire cavity surface 13. The side region MS is an annular region sandwiched between a first arc (not shown) connecting the intersections of the first perpendicular line VT1 and the tire cavity surface 13 in the tire circumferential direction, and a second arc (not shown) connecting the intersections of the second perpendicular line VT2 and the tire cavity surface 13 in the tire circumferential direction.

[0037] The lead-out portion 43 electrically connects the loop coil portion 42 and the electronic circuit board 46. The lead-out portion 43 shown in FIG. 2 is an extended portion of the conductive wire constituting the loop coil portion 42, and both ends are connected to the electronic circuit board 46 arranged outside the loop coil portion 42. The lead-out portion 43 is arranged radially outward from the loop coil portion 42. The lead-out portion 43 is a conductive wire that extends from a base end 43A formed by bending both ends of a conductive wire wound around the tire center axis toward the radially outer side of the loop coil portion 42 to a tip end 43B that contacts the outer edge 46E of the electronic circuit board 46. The length of the conductive wire of the lead-out portion 43 is preferably 5 mm or more, and more preferably 10 mm or more. By having a length of 5 mm or more, the electronic circuit board 46 is less susceptible to the influence of the magnetic field generated around the loop coil portion 42. Although not shown, the electronic circuit board 46 is mounted with, for example, a resonance capacitor for the power receiving coil 40 and a rectifier circuit that converts the received AC power into DC power.

[0038] The lead-out portion 43 is disposed so as to intersect with the belt-adjacent region MR (FIG. 1). The belt-adjacent region MR is an annular region whose outer edge is an arc (second arc) formed by connecting the intersections of the second perpendicular line VT2 and the tire cavity surface 13 in the tire circumferential direction, and whose inner edge is a position spaced from the second perpendicular line VT2 along the tire cavity surface 13 toward the bead portion A by a length Fx expressed by the following formula (2). The length Fx can be measured by placing a tape measure against the tire cavity surface 13.

[0039] Fx = 0.12 × SH (1)

[0040] Because the pull-out portion 43 intersects with the belt-adjacent region MR, the loop coil portion 42 and the electronic circuit board 46 are disposed outside the belt-adjacent region MR. In other words, the electronic circuit board 46 is disposed in a portion that overlaps with the belt 20 in the tire radial direction. It is preferable that the only metal member disposed in the belt-adjacent region MR is the conductor that constitutes the pull-out portion 43. Here, examples of metal members include reinforcing materials using metal cords and electronic circuits such as RFID.

[0041] As shown in FIG. 3 , the lead-out portion 43 is inclined toward one side in the tire circumferential direction from the base end 43A connected to the loop coil portion 42 toward the tire radial outside. The pair of conductors constituting the lead-out portion 43 are linearly arranged when viewed from the tire widthwise inside. The pair of conductors constituting the lead-out portion 43 are arranged parallel to each other in the range from the base end 43A connected to the loop coil portion 42 to the outer edge 46E of the electronic circuit board 46. Here, "parallel" does not necessarily mean that the pair of conductors are completely parallel, but also includes cases where they extend within a range of ±10°. From the viewpoint of power supply efficiency, it is preferable that the lead-out portion 43 be spaced a certain distance in the tire radial direction from the loop coil portion 42. Furthermore, from the viewpoint of durability, it is preferable that the lead-out portion 43 be spaced a certain distance in the tire circumferential direction from the base end 43A connected to the loop coil portion 42.

[0042] The drawn-out portion 43 shown in FIG. 3 is disposed at a position where the distance W in the tire width direction satisfies the following formula (2). The distance W is the distance in the tire width direction between the base end 43A connected to the loop coil portion 42 and the tip end 43B intersecting with the outer edge 46E of the electronic circuit board 46. The distance W is the distance along the tire cavity surface 13. SH is the tire cross-sectional height (FIG. 1). The base end 43A connected to the loop coil portion 42 refers to the point where the loop coil portion 42 is bent radially outward.

[0043] 0.1≦W / SH≦1.0 (2)

[0044] By arranging the lead-out portion 43 within a range where the distance W and the tire cross-sectional height SH satisfy the above formula, it is possible to suppress a decrease in power supply efficiency.

[0045] The distance W is the distance between the base end 43A of the drawn-out portion 43 connected to the loop coil portion 42 and the tip end 43B intersecting with the outer edge 46E of the electronic circuit board 46, projected onto the tire cavity surface 13. For example, a first imaginary line VR1 is drawn in the tire circumferential direction from the outer edge 46E of the electronic circuit board 46. Next, a second imaginary line VR2 is drawn in the tire radial direction from the base end 43A connected to the loop coil portion 42, and an intersection point P1 between the first imaginary line VR1 and the base end 43A connected to the loop coil portion 42 is determined. Finally, a tape measure is placed along the second imaginary line VR2, and the distance on the tire cavity surface 13 between the base end 43A connected to the loop coil portion 42 and the intersection point P1 is measured, and this length is defined as the distance W.

[0046] It is more preferable that the lead-out portion 43 is disposed at a position where the distance W in the tire radial direction satisfies 0.2≦W / SH≦1.0. The distance W may be 10 mm or more and 80 mm or less, or 20 mm or more and 70 mm or less.

[0047] The lead-out portion 43 shown in Fig. 3 is disposed at a position where the tire circumferential distance L1 satisfies the following formula (3). The tire circumferential distance L1 is the distance in the tire circumferential direction between the base end 43A connected to the loop coil portion 42 and the tip end 43B intersecting with the outer edge 46E of the electronic circuit board 46. The distance L1 is the distance along the tire cavity surface 13. The tire circumferential length LC is the tire circumferential length of the tread surface 34 at the tire equatorial plane CP.

[0048] 0.002≦L1 / LC≦0.030 (3)

[0049] By arranging the drawn-out portion 43 in a range in which the distance L1 and the tire circumferential direction length LC satisfy the above formula (3), the drawn-out portion 43 is less likely to break due to deformation when the tire 10 contacts the ground. The drawn-out portion 43 may be arranged on one side or the other side in the tire circumferential direction with respect to the base end 43A connected to the loop coil portion 42.

[0050] Distance L1 is the length of loop coil portion 42 between the base end 43A and the tip 43B of lead-out portion 43 projected onto loop coil portion 42. For example, a third imaginary line VR3 is drawn in the tire radial direction from tip 43B, which intersects with the outer edge 46E of electronic circuit board 46, toward loop coil portion 42. The length in the tire circumferential direction between the third imaginary line VR3 and second imaginary line VR2 is defined as distance L1. If lead-out portion 43 is made up of multiple conductors, the smaller of the distances L1 measured for each conductor is used.

[0051] It is more preferable that the lead-out portion 43 is disposed at a position where the distance L1 in the tire circumferential direction satisfies 0.004≦L1 / LC≦0.025. The distance L1 may be 5 mm or more and 60 mm or less, or 10 mm or more and 50 mm or less.

[0052] The pull-out portion 43 is preferably disposed in a predetermined direction relative to the belt-adjacent region MR. The pull-out portion 43 shown in FIG. 3 is disposed at a position where the tire circumferential distance L2 satisfies the following formula (4). The tire circumferential distance L2 is the tire circumferential distance between an intersection P3 between the outer edge of the belt-adjacent region MR and the pull-out portion 43, and an intersection P4 between the inner edge of the belt-adjacent region MR and the pull-out portion 43. The distance L2 is the distance along the tire cavity surface 13. The intersections P3 and P4 are the tire circumferential midpoints of the two conducting wires that make up the pull-out portion 43.

[0053] 0.25≦L2 / Fx≦4.00 (4)

[0054] By arranging the pull-out portion 43 within a range where the distance L2 and Fx satisfy the above formula (4), it is possible to prevent breakage of the conductive wire that constitutes the pull-out portion 43. The distance L2 is the distance in the tire circumferential direction between a point P41 obtained by projecting an intersection P4 between the inner edge of the belt-adjacent region MR and the pull-out portion 43 onto the outer edge of the belt-adjacent region MR, and an intersection P3 between the outer edge of the belt-adjacent region MR and the pull-out portion 43.

[0055] The lead-out portion 43 is preferably disposed in a predetermined direction relative to the base end 43A connected to the loop coil portion 42. The lead-out portion 43 shown in FIG. 3 is disposed at a position where the tire circumferential distance L3 satisfies the following formula (5). The tire circumferential distance L3 is the tire circumferential distance between a midpoint P5 of the pair of base ends 43A connected to the loop coil portion 42 and a midpoint P6 of the pair of tips that intersects with the outer edge 46E of the electronic circuit board. The distance L3 is the tire circumferential distance along the tire cavity surface 13 between the points obtained by projecting the midpoint P5 and the midpoint P6 onto the first virtual line VR1. W is the tire radial distance between the midpoints P5 and P6.

[0056] 0.25≦L3 / W≦4.00 (5)

[0057] By arranging the lead-out portion 43 within a range in which the distance L3 and the distance W in the tire radial direction satisfy the above formula (5), breakage of the conductive wire constituting the lead-out portion 43 due to deformation during tire rotation can be more reliably prevented.

[0058] In the tire 10, it is preferable that the tire thickness Ga at the outer edge 46E where the drawn-out portion 43 of the electronic circuit board 46 intersects and the tire thickness Gb at the inner edge of the belt adjacent region MR satisfy the following formula (6).

[0059] 0.30≦Gb / Ga≦0.80 (6)

[0060] The tire thickness Ga refers to the distance between the intersection of a third perpendicular line VT3, which passes through the tip 43B of the drawn-out portion 43 where the outer edge 46E of the electronic circuit board 46 and the drawn-out portion 43 intersect, and extends toward the tire cavity surface 13 in the normal direction to the tire cavity surface 13, and the tire cavity surface, and the intersection of the third perpendicular line VT3 and the tire outer surface. The tire thickness Gb refers to the distance between the intersection of a fourth perpendicular line VT4, which passes through the inner edge of the belt-adjacent region MR and extends toward the tire cavity surface 13 in the normal direction to the tire cavity surface 13, and the tire cavity surface 13, and the intersection of the fourth perpendicular line VT4 and the tire outer surface. When the tire thicknesses Ga and Gb are within the above ranges, the tire main body 11 has appropriate rigidity in the belt-adjacent region MR. It is more preferable that the tire thicknesses Ga and Gb satisfy the relationship 0.35≦Gb / Ga≦0.75.

[0061] The tire 10 may have a first additional reinforcing layer 49 that suppresses deformation of the pull-out portion 43. The first additional reinforcing layer 49 is provided on the outer side in the tire width direction, further outward in the tire radial direction of the belt 20 at a location where the belt 20 has only one layer. The tire 10 has lower rigidity at the location on the outer side in the tire width direction where the belt 20 has only one layer than at a location closer to the tire equatorial plane CP where the belt 20 has two layers. The tire 10 according to the present embodiment suppresses a decrease in rigidity at the location where the belt 20 has only one layer by providing the first additional reinforcing layer 49. The tire 10 may also have a second additional reinforcing layer 51 that extends further outward in the tire width direction from the outer end of the belt 20 in the tire width direction. The second additional reinforcing layer 51 is arranged on the outer side in the tire width direction where the belt 20 is not present. The tire 10 has lower rigidity at the outer location in the tire width direction where the belt 20 is not present than at a location where the belt 20 has two layers and a location where the belt 20 has only one layer. The tire 10 according to this embodiment is provided with the second additional reinforcing layer 51 to suppress a decrease in rigidity at outer locations in the tire width direction where the belt 20 is not present. The position at which the second additional reinforcing layer 51 is provided may overlap the belt adjacent region MR in the tire radial direction. The second additional reinforcing layer 51 may extend beyond the belt adjacent region MR to the outer side in the tire radial direction. The first additional reinforcing layer 49 and the second additional reinforcing layer 51 may be integral.

[0062] The tire 10 of this embodiment described above is obtained through each of the usual manufacturing steps, i.e., a tire material mixing step, a tire material processing step, a green tire molding step, a vulcanization step, and a post-vulcanization inspection step, etc. When manufacturing the tire of this embodiment, convex portions and concave portions corresponding to a predetermined tread pattern are formed on the inner wall of a vulcanization mold, and vulcanization is carried out using this mold.

[0063] The tire 10 may be formed by placing the power receiving coil 40 and the electronic circuit board 46 on a green tire before the vulcanization process and then undergoing the vulcanization process, or the power receiving coil 40 and the electronic circuit board 46 may be fixed to the tire inner cavity surface after vulcanization.

[0064] (Action and effect) A tire 10 mounted on a vehicle (not shown) deforms mainly on the contact patch side when rotating. That is, when the tire 10 is viewed from the outside in the tire width direction, the tire 10, which is a nearly perfect circle, deforms into a shape that conforms to the road surface on the contact patch side. Also, in a tire meridian cross section, the tire 10 deforms so that the sidewall portion B on the contact patch side bulges outward in the tire radial direction. The sidewall portion B has the largest deformation amount on the side of the side region MS closest to the contact patch, i.e., the belt adjacent region MR. The tire cavity surface 13 is integral with the sidewall portion B, and therefore deforms in the same way as the sidewall portion B.

[0065] The power receiving coil 40 is provided on the tire cavity surface 13 and is therefore affected by deformation of the tire cavity surface 13. The conducting wire that makes up the power receiving coil 40 is made of metal, and is therefore more rigid and less likely to deform than the inner liner 12 that makes up the tire cavity surface 13.

[0066] Incidentally, if the entire power receiving coil were fixed to the tire cavity surface, it would deform integrally with the tire cavity surface. The power receiving coil's conducting wires are harder and less likely to deform than the tire rubber, so if the tire deforms significantly, they will not be able to follow the tire deformation and may break.

[0067] Because the loop coil portion 42 of the power receiving coil 40 is provided within the side region MS of the tire cavity surface 13, the magnetic field is less susceptible to the influence of the bead core 14 and the belt 20, and a decrease in power supply efficiency can be suppressed. Furthermore, because the loop coil portion 42 has a circular shape centered on the tire rotation axis when viewed in the tire width direction, the length of the loop coil portion 42 in the tire radial direction at the sidewall portion B in the tire meridian cross section is short. Therefore, the loop coil portion 42 is less affected by deformation of the sidewall portion B. Furthermore, because the loop coil portion 42 has a circular shape centered on the tire rotation axis, fluctuations in the amount of power received during tire rotation can be suppressed, and a decrease in power supply efficiency can be suppressed.

[0068] Because the loop coil portion 42 is provided in the side region MS, when viewed from the outside in the tire width direction, it deforms in a direction along the road surface together with the tire cavity surface 13, but the amount of deformation of the loop coil portion 42 at each end of the leading side and trailing side in the contact patch is smaller than the amount of deformation in the tire width direction in the tire meridian cross section. The tire 10 deforms approximately flat along the road surface in the contact patch between the leading side end and the trailing side end.

[0069] Furthermore, since the loop coil portion 42 has a circular shape centered on the tire rotation axis, it is less susceptible to deformation in the tire width direction in the tire meridian cross section, which has a larger deformation amount.

[0070] The pull-out portion 43 has an outer edge defined by an arc (second arc) connecting intersections of the second perpendicular line VT2 and the tire cavity surface 13 in the tire circumferential direction, and intersects with the belt adjacent region whose inner edge is located at a position spaced a distance Fx expressed by the above formula (1) Fx = 0.12 × SH from the second perpendicular line VT2 along the tire cavity surface 13 toward the bead portion A. In a meridian cross section, the pull-out portion 43 deforms in the longitudinal direction of the conductor due to deformation of the tire cavity surface 13 in the tire width direction.

[0071] Because the pull-out portion 43 intersects with the belt-adjacent region MR, the loop coil portion 42 and the electronic circuit board 46 are positioned outside the belt-adjacent region MR. That is, the loop coil portion 42 is disposed in the side region MS, which is less susceptible to the influence of the bead core 14 and the belt 20, and the electronic circuit board 46 is positioned closer to the tire equatorial plane CP than the belt-adjacent region MR, thereby suppressing a decrease in power supply efficiency. Because the higher rigidity of the belt 20 suppresses local deformation on the tire equatorial plane CP side than the belt-adjacent region MR, the electronic circuit board 46 is less likely to fall off from the tire cavity surface 13, thereby improving durability.

[0072] The lead-out portion 43 is disposed within a predetermined range in the tire radial direction from the loop coil portion 42 by satisfying the above formula (2) 0.1≦W / SH≦1.0. That is, by having W / SH equal to or greater than the above lower limit, the tire 10 can suppress the occurrence of eddy current loss on the electronic circuit board 46. Furthermore, by having W / SH equal to or less than the above upper limit, the tire 10 can suppress the resistance value of the power receiving coil 40 from increasing. Therefore, by satisfying the above formula (1), the tire 10 can suppress a decrease in power supply efficiency.

[0073] In addition to the above formula (2), the drawn-out portion 43 satisfies the above formula (3), 0.002≦L1 / LC≦0.030, so that the drawn-out portion 43 is disposed at a position a predetermined distance away in the tire circumferential direction from the base end 43A connected to the loop coil portion 42. That is, when L1 / LC is equal to or greater than the above lower limit, the tire 10 can reduce the risk of the drawn-out portion 43 breaking due to deformation of the shoulder portion C and the sidewall portion B. Furthermore, when L1 / LC is equal to or less than the above upper limit, the overlapping region between the drawn-out portion 43 and the loop coil portion 42 in the tire circumferential direction can be set to an appropriate range, so that an increase in noise and a decrease in power supply efficiency can be suppressed.

[0074] The pull-out portion 43 is arranged in a predetermined direction with respect to the belt-adjacent region MR by satisfying the above formula (4) 0.25≦L2 / Fx≦4.00. That is, by having L2 / F2 within the above range, the pull-out portion 43 is arranged in a predetermined direction with respect to the belt-adjacent region MR. The belt-adjacent region MR has a large amount of deformation outward in the tire width direction in a tire meridian cross section. By arranging the pull-out portion 43 in a predetermined direction with respect to the belt-adjacent region MR, deformation of the conductor extending in the longitudinal direction is suppressed. Therefore, the tire 10 can reduce the risk of breakage of the pull-out portion 43.

[0075] By satisfying the above formula (5) 0.25≦L3 / W≦4.00, the drawn-out portion 43 is arranged in a predetermined direction in the range from the base end 43A connected to the loop coil portion 42 to the tip end 43B connected to the electronic circuit board 46. In other words, by having L3 / W within the above range, the tire 10 can reduce the risk of the drawn-out portion 43 breaking due to deformation of the shoulder portion C and the sidewall portion B.

[0076] By satisfying the above formula (6) 0.30≦Gb / Ga≦0.80, the tire 10 obtains a tire main body 11 having appropriate rigidity in the belt-adjacent region MR. With the rigidity in the belt-adjacent region MR in the tire 10 within an appropriate range, durability of the pull-out portion 43 is improved and an increase in rolling resistance can be suppressed.

[0077] By having at least one of the first additional reinforcing layer 49 and the second additional reinforcing layer 51, the tire 10 can suppress a decrease in rigidity in the belt-adjacent region MR of the tire 10, thereby suppressing deformation of the belt-adjacent region MR and the pull-out portion 43.

[0078] (Variation) The present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the present invention.

[0079] In the tire 10, it is preferable that the difference between the angle of the tire ground contact edge and the angle of the drawn-out portion is within a predetermined range. As shown in Fig. 4, the drawn-out portion 43a is arranged in a direction along the tire ground contact edge that satisfies the following formula (7). H is the maximum ground contact width of the tire, S8 is the ground contact length at a position (0.8H) that is 80% of the maximum ground contact width, and S9 is the ground contact length at a position (0.9H) that is 90% of the maximum ground contact width. The ground contact lengths are the lengths in the circumferential direction of the tire.

[0080] 0.025≦(|S8-S9|) / H≦0.400···(7)

[0081] The maximum contact width H refers to the maximum length of the contact edge in the tire width direction. The contact edge is the maximum position in the tire width direction of the contact surface between the tire and a flat plate when the tire 10 is mounted on a standard rim, pressurized to the standard internal pressure, placed perpendicular to a flat plate in a stationary state, and subjected to a load corresponding to 80% of the standard load. As shown in Figure 4, the contact width, which is the tire width direction length of the contact edge, varies in the tire circumferential direction. That is, the contact width of the tire 10 shown in Figure 4 is maximum at approximately the center of the contact surface in the tire circumferential direction and gradually decreases toward both ends in the tire circumferential direction.

[0082] By satisfying the above formula (7), the difference between the angle α1 of the ground contact end with respect to the tire rotation axis as viewed from the tire radial direction when the tire 10 is in contact with the ground and the angle α2 of the conductor of the pull-out portion 43a with respect to the tire rotation axis as viewed from the tire radial direction can be kept within a predetermined range. For the tire 10, it is preferable that the difference between the angle α1 of the ground contact end with respect to the tire rotation axis as viewed from the tire radial direction and the angle α2 of the conductor of the pull-out portion 43 is smaller when the tire 10 is stepped on. In other words, it is preferable that the pull-out portion 43a is inclined at the predetermined angle α2 from the base end 43A connected to the loop coil portion 42 toward the outer side in the tire width direction toward the leading-in side in the tire circumferential direction.

[0083] By satisfying the above formula (7), 0.025≦(|S8−S9|) / H≦0.400, the tire 10 is arranged such that the drawn-out portion 43a is oriented along the ground-contact edge. The tire 10 deforms such that the shoulder portion C and the sidewall portion B bulge outward in the tire width direction before and after contact with the road surface. By keeping the difference between the angle α1 of the ground-contact edge when the tire 10 contacts the road surface and the angle α2 of the conductor of the drawn-out portion 43a relative to the tire circumferential direction within a predetermined range, there is little difference between the deformation direction of the shoulder portion C and the sidewall portion B and the extension direction of the conductor of the drawn-out portion 43a when the tire 10 is stepped on or kicked off. In other words, the conductor of the drawn-out portion 43a can absorb the load received due to the deformation of the shoulder portion C and the sidewall portion B as a whole. This allows the conductor of the drawn-out portion 43a to be suppressed from instantaneous and local deformation, resulting in excellent durability.

[0084] Incidentally, if the difference between the angle α1 of the contact end when the tire 10 comes into contact with the ground and the angle α2 of the conductor of the pull-out portion 43a relative to the tire circumferential direction is too large, the pull-out portion 43a is likely to be subjected to instantaneous and localized loads from the shoulder portion C and the sidewall portion B at least when stepping on or kicking off, making it more likely to break.

[0085] As shown in Fig. 5, in the tire 10, the angle θ formed between the steel cords of the belt layers 20a, 20b and the conductor wires of the pull-out portion 43b is preferably 55° or less. In the tire shown in Fig. 1 which includes two belt layers 20a, 20b, the angle θ of the one of the two belt layers 20a, 20b which is smaller than the angle formed between the steel cords of the pull-out portion 43b is preferably 55° or less. The angle θ formed between the steel cords of the belt layers 20a, 20b and the conductor wires of the pull-out portion 43b is more preferably 50° or less, and even more preferably 40° or less.

[0086] In the tire 10, the angle formed between the steel cords of the belt layers 20a, 20b and the conductor of the pull-out portion 43b is 55° or less, so that the pull-out portion 43b is arranged in a direction along the steel cords of at least one belt layer. Since the belt layers 20a, 20b hardly deform in the extending direction of the steel cords, the smaller the angle formed between the steel cords and the conductor of the pull-out portion 43b, the smaller the deformation amount of the pull-out portion 43b. Therefore, by setting the angle formed between the steel cords of the belt layers 20a, 20b and the conductor of the pull-out portion 43b to 55° or less, the pull-out portion 43b has excellent durability.

[0087] In the above embodiment, the pull-out portion 43 is inclined to one side in the tire circumferential direction from the base end 43A connected to the loop coil portion 42 toward the tire radial outside, but the present invention is not limited to this. As shown in FIG. 6, the pull-out portion 43c may be disposed at a position along the tire radial direction from the base end 43A connected to the loop coil portion 42. The pull-out portion 43c is disposed at a position where the distance W in the tire radial direction satisfies the above formula (1). By satisfying at least the above formula (1), the pull-out portion 43c can obtain the same effect as the above embodiment.

[0088] 7, the pull-out portion 43d may have a portion inclined toward one side in the tire circumferential direction from the base end 43A connected to the loop coil portion 42 toward the tire radially outward, and a portion disposed along the tire radial direction. The pull-out portion 43d shown in FIG. 7 extends from the base end 43A connected to the loop coil portion 42 to the outer edge of the belt adjacent region MR, inclined toward one side in the tire circumferential direction toward the tire radially outward, and extends in the tire radial direction from the outer edge of the belt adjacent region MR to the outer edge of the electronic circuit board 46. The pull-out portion 43d can achieve the same effect as the above embodiment by satisfying at least the above formula (1). The pull-out portion 43d shown in FIG. 7 can also satisfy the above formulas (2) to (7). Furthermore, in the pull-out portion 43d shown in FIG. 7, the angle formed between the steel cords of the belt layers 20a, 20b and the conductor of the pull-out portion 43d may be 55° or less.

[0089] In the above embodiment, the lead-out portion 43 has been described as having a pair of conductors arranged in a straight line when viewed from the inner side in the tire width direction, but the present invention is not limited to this. As shown in FIG. 8, the lead-out portion 43e may have a pair of conductors arranged in a curved line. The lead-out portion 43e can achieve the same effects as the above embodiment by satisfying at least the above formula (1). The lead-out portion 43e shown in FIG. 8 can also satisfy at least the above formulas (2) to (5).

[0090] In the above embodiment, the pair of conductors constituting the lead-out portion 43 are arranged parallel to each other in the range from the base end 43A connected to the loop coil portion 42 to the outer edge 46E of the electronic circuit board 46. However, the present invention is not limited to this. As shown in FIG. 9, the lead-out portions 43f may intersect each other. In the lead-out portion 43f shown in FIG. 7, the pair of conductors constituting the lead-out portion 43f are inclined toward each other in the tire circumferential direction from the base end 43A connected to the loop coil portion 42 to the outer edge of the belt-adjacent region MR toward the tire radially outward side, and are inclined toward opposite sides in the tire circumferential direction from the outer edge of the belt-adjacent region MR toward the tire radially outward side to the outer edge of the electronic circuit board 46. The pair of conductors intersect each other at the inner edge of the belt-adjacent region MR. The lead-out portion 43f can achieve the same effect as the above embodiment by satisfying at least the above formula (1).

[0091] Furthermore, the lead-out portion 43f shown in FIG. 9 can satisfy at least the above formulas (2) and (7). For example, by installing the lead-out portion 43f in a tire that satisfies the above formula (7), the difference between the extending direction of one of the pair of conductors constituting the lead-out portion 43f and the deformation direction of the shoulder portion C and the sidewall portion B is reduced, thereby achieving the same effect as the above embodiment. Furthermore, the lead-out portion 43f shown in FIG. 9 may have an angle of 55° or less between the steel cords of the belt layers 20a, 20b and the conductors of the lead-out portion 43d. That is, by setting the angle between one of the pair of conductors constituting the lead-out portion 43f and the steel cords of the belt layers 20a, 20b to 55° or less, the lead-out portion 43f can achieve the same effect as the above embodiment.

[0092] 2. Wireless Power Supply System 10 is a diagram showing a tire 10 (a portion on one side in the tire width direction with reference to the tire equatorial plane CP in a tire meridian cross section of the tire on the non-ground-contact side) provided with a power transmitting coil 52 and a power receiving coil 40 in a wireless power supply system 50 according to this embodiment. Note that Fig. 10 shows the tire portion on the opposite side from the ground contact surface when the tire is mounted on a rim, pressurized to a normal internal pressure, and subjected to a load of 80% of the normal load (the same applies hereinafter to the invention of a wireless power supply system).

[0093] The power transmission coil 52 shown in the figure forms a resonant circuit using a capacitor and a coil, and is attached, for example, to the tire-side surface of a knuckle or hub carrier, which are components of a steering axle of a vehicle (not shown), or to one of the components that make up the strut structure.

[0094] Next, the power receiving coil 40 shown in Fig. 10 has the same configuration as the power receiving coil shown in Fig. 1, and a resonant circuit is formed by a capacitor and a coil. Note that the tire 10 shown in Fig. 10 is a tire of the basic configuration 1 related to the tire 10 described above, and a tire that adds at least one of additional configurations 2 to 8 to the basic configuration 1, and its actions, functions, etc. are as described above.

[0095] Under these assumptions, the wireless power feed system 50 according to this embodiment is a magnetic field resonance type wireless power feed system that uses an AC magnetic field, and as shown in Fig. 10, power is fed to the power transmitting coil 52, and the power is transmitted to the power receiving coil 40 by the AC magnetic field. With this wireless power feed system 50, as described above, it is possible to improve the power feeding efficiency.

[0096] Here, it is preferable to transmit power of 0.1 to 15 W at a frequency of 1 to 20 MHz to drive sensors and associated electrical circuits installed inside the tire 10. More preferably, AC power with a frequency of 6.78 to 13.56 MHz is applied to the power transmission coil 52.

[0097] Furthermore, the shortest distance between the power transmitting coil 52 and the power receiving coil 40 (hereinafter sometimes referred to as the "transmission gap G") is preferably 10 mm or more and 80 mm or less. Here, the transmission gap G is a value measured when the tire 10 is mounted on a rim, pressurized to the normal internal pressure, mounted on a vehicle, and stopped on flat ground. The transmission gap G is the shortest distance between the power transmitting coil 52 and the power receiving coil 40, i.e., in FIG. 10, it refers to the distance between the innermost position of the power transmitting coil 52 in the tire width direction and the outermost position of the power receiving coil 40 in the tire width direction.

[0098] Setting the transmission gap G to 10 mm or more can prevent excessive fluctuations in received power caused by fluctuations in the relative positions of the power transmitting coil 52 and the power receiving coil 40 shown in FIG. 10 in the direction of power transmission, simplifying the circuit configuration connected to the power receiving coil 40 and thereby facilitating stable power supply to an electronic device. The fluctuations in received power depend on fluctuations in the relative positions between the two coils 52, 40 caused by slight expansion of the tire 10 due to centrifugal force while the tire 10 is rotating. Specifically, as the tire rotation speed increases, the tire 10 expands in the tire radial direction, causing the power receiving coil 40 to move radially outward (toward the top of FIG. 10 ), while the position of the power transmitting coil 52 remains unchanged, resulting in a change in the relative positions between the two coils 52, 40.

[0099] In contrast to this, by setting the transmission gap G to 80 mm or less, the strength of the magnetic field generated between the two coils 52, 40 does not become excessively small, and power can be efficiently supplied by the AC magnetic field.

[0100] The transmission gap G is more preferably 12 mm or more and 75 mm or less, and most preferably 15 mm or more and 70 mm or less.

[0101] By adopting the above-described range of transmission gap G, power range, and frequency band, not only can the temperature rise of the power receiving coil 40 be suppressed, but also an increase in the number of coil turns (and thus an increase in coil weight) is unnecessary, so that the rolling resistance of the tire is not increased, power can be fed efficiently, and excellent power feeding efficiency can be achieved. Furthermore, in particular, according to the above-described range of transmission gap G, excellent power feeding efficiency can be obtained when power is transmitted using the tire structure in magnetic field resonance type wireless power feeding in the above frequency band.

[0102] 10, the power transmitting coil 52 is disposed so as to extend in the tire radial direction, but this embodiment is not limited to such an arrangement. That is, as long as the transmission gap G described above is within a predetermined range, the extension direction of the power transmitting coil 52 may be inclined with respect to the tire radial direction.

[0103] When the power receiving coil 40 is provided on the inside of the vehicle mounting surface, the power transmitting coil 52 can be installed inside the wheel house, thereby easily keeping the transmission gap G within the above range.

[0104] In a tire meridian cross section, it is preferable that at least a portion of the power receiving coil 40 be located within a power supply region that extends in the winding axis direction of the power transmitting coil 52 across both longitudinal ends of the power transmitting coil 52.

[0105] Here, the positional relationship between the power receiving coil 40 and the power transmitting coil 52 is measured with the tire 10 mounted on a rim, pressurized to the normal internal pressure, attached to a vehicle, and stopped on flat ground. More preferably, the power transmitting coil 52 is arranged so that the power transmitting coil radial direction area defined by the length between both ends of the tire in the radial direction overlaps at least a part of the power receiving coil radial direction area defined by the length between both ends of the tire in the radial direction. Such an arrangement can achieve higher power transfer efficiency.

[0106] 11(A) and 11(B) is disposed on the outer side in the tire width direction, at a position corresponding to a partial region in the tire circumferential direction. The power receiving coil 40 provided on the tire cavity surface extends around the entire tire circumferential direction. At least a portion of the power receiving coil 40 is provided in a region obtained by projecting the power transmitting coil radial region onto the tire cavity surface, i.e., a region between points where imaginary lines extending from the tire radially outer end and the tire radially inner end of the power transmitting coil 52 to the tire cavity surface and parallel to the winding axis of the power transmitting coil 52 intersect with the tire cavity surface. For the power receiving coil 40 provided on the tire cavity surface, it is preferable that a portion of the tire radial direction of the power receiving coil 40 is included in the region obtained by projecting the power transmitting coil radial region, and it is more preferable that the entire tire radial direction of the power receiving coil 40 is included in the region obtained by projecting the power transmitting coil radial region.

[0107] In the wireless power supply system 50 according to this embodiment, the power transmission coil 52 is attached to a knuckle or hub carrier (located on the outer side of the sidewall portion B in the tire width direction), which is a part of the steering axle of the vehicle, or to the tire-side surface of any part constituting the strut structure. Therefore, when examining the power supply efficiency taking into account the shape of the tire 10, particularly the sidewall portion B, it is desirable that the direction of the magnetic field lines penetrating the tire at the sidewall portion B, and therefore the power supply direction Dp, be approximately the tire width direction, as shown in Figures 11(A) and 11(B).

[0108] Based on this knowledge, when the power supply direction Dp is set to be substantially in the tire width direction as shown in Figures 11(A) and (B), power supply can be performed more efficiently, and ultimately excellent power supply efficiency can be achieved.

[0109] Furthermore, in the examples shown in Figures 11(B) and (C), the constituent surfaces (planes normal to the winding axes of each coil in Figures 11(B) and (C)) of the transmitting coil 52 and the receiving coil 40 are parallel to each other, so power can be supplied more efficiently than in the examples shown in Figures 11(A) and (D), and superior transmission efficiency can be achieved.

[0110] 11(A) and 11(D), the constituent surfaces of the power transmitting coil 52 and the power receiving coil 40 do not need to be parallel to each other. This is because, when the magnetic field generated by the power transmitting coil 52 interlinks with the power receiving coil 40, an electromotive force is generated by the AC magnetic field, and there are no restrictions on the relative orientation of the surfaces.

[0111] The power transmission coil 52 is preferably installed within a range of 60° on both sides in the tire circumferential direction, centered on an imaginary line extending vertically upward from the center of the tire.

[0112] Typically, when the tire 10 rolls, the power receiving coil 40 deforms in accordance with the deformation of the tire 10 at the contact portion of the tire 10, whereas the power receiving coil 40 in a portion of the tire 10 away from the contact portion (the upper portion of the tire 10 in FIG. 12 ) hardly deforms in accordance with the tire deformation. For this reason, by installing the power transmitting coil 52 located on the outside of the tire 10 near the upper portion of the tire away from the contact portion of the tire 10 (a tire circumferential range R extending 60° on both sides of an imaginary line extending vertically upward from the tire center O), it is possible to suppress fluctuations in the transmission gap G described above when the tire rolls, thereby enabling more efficient power transfer and ultimately achieving even better power transfer efficiency. Note that the example shown in FIG. 12 is an example in which the power transmitting coil 52 is attached to a wheel well 54, and the tire circumferential range R described above is applied within the wheel well 54.

[0113] It is more preferable that the power transmission coil 52 be installed within a circumferential range of 55° on either side of an imaginary line extending vertically upward from the tire center O, and it is extremely preferable that the power transmission coil 52 be installed within a circumferential range of 50° on either side of the imaginary line.

[0114] Furthermore, the shape of the power transmission coil 52 is not particularly limited, but when the power transmission coil 52 is installed, for example, inside a wheelhouse, it is preferable to use a so-called spiral coil, which allows the overall thickness to be reduced.

[0115] Although the case where the power transmitting coil unit 56 includes the case 58 has been described, the present invention is not limited to this. The power transmitting coil unit 56 may have a power transmitting coil 52 and a resin film that covers the power transmitting coil 52. In this case, the power transmitting side surface refers to the surface of the resin film that faces the power receiving coil 40. The power transmitting coil unit 56 may also be composed of the power transmitting coil 52. In this case, the power transmitting side surface refers to the surface of the power transmitting coil 52 that faces the power receiving coil 40.

[0116] It is preferable that the angle β that the power transmission side surface 60 of the power transmission coil unit 56 including the power transmission coil 52 makes with the tire radial direction as viewed from the tire meridian cross section is in the range of 70° toward the tire 10 and 30° away from the tire 10, with the tire radial inner end 57 of the power transmission coil unit 56 as the center.

[0117] As described above, the power transmitting coil unit 56 may have a power transmitting coil 52 and a case 58 that houses the power transmitting coil 52. As shown in Fig. 13 , the case 58 has a power transmitting side surface 60, and the angle formed between the power transmitting side surface 60, which is centered on the lower end of the power transmitting coil unit 56 in the tire radial direction, and the tire radial direction is defined as β. The angle β is in the range of 70° toward the tire 10 and 30° away from the tire radial direction.

[0118] The power transmission side surface 60 of the power transmission coil unit 56 facing the power receiving coil 40 is less likely to get wet because the angle β between the power transmission side surface 60 and the tire circumferential direction when viewed from the tire meridian cross section is within the above range, making it easy to install the power transmission coil unit 56 at an angle and position that allows efficient power supply to the power receiving coil 40. <Other forms of tires and wireless power supply systems> The tire and the wireless power supply system according to the present invention have been described above. Other matters relating to the tire and the wireless power supply system according to the present invention will be listed below.

[0119] The carbon content of the inner liner 12, which is a component of the tire 10, is preferably 45 to 75 parts by mass (mass parts when the rubber is 100, the same applies below), the carbon content of the side tread is 25 to 65 parts by mass, the carbon content of the bead filler 16 is 40 to 80 parts by mass, and the carbon content of the covering rubber of the carcass 18 is 35 to 70 parts by mass. By adopting these respective content amounts, it is possible to achieve the desired rubber properties in each rubber layer. Note that, while the thermal conductivity of rubber is usually determined by the type of polymer and compounding ingredients, adjusting the carbon content is most preferable because it makes it easy to change the heat dissipation properties, thereby ensuring durability while maintaining the rubber properties required for a tire.

[0120] 10, the power receiving coil 40 is preferably provided in the tire cavity of the sidewall portion B of the tire 10 with its constituent surface facing in the tire width direction. As described above, when the power feeding direction of the power transmitting coil 52 is set to be approximately the tire width direction, as shown in FIGS. 11(A) and 11(B), by providing the power receiving coil 40 with its constituent surface facing in the tire width direction, the power feeding surface of the power transmitting coil 52 and the constituent surface of the power receiving coil 40 become parallel. This allows power feeding to be performed more efficiently, and ultimately realizes excellent power feeding efficiency.

[0121] Figure 14 is a diagram showing arrangements of the receiving coil 40, where (A) to (F) are examples showing a receiving coil 40 consisting of 2, 3, 4, 5, 6, and 8 sets of loop coil sections 40a, respectively, (G) is an example in which multiple loop coil sections 40a are stacked in the tire radial direction, and (H) is an example in which some of the multiple loop coil sections 40a extend at an angle relative to the tire radial direction.

[0122] As shown in Figures 14(A) to 14(H), the power receiving coil 40 may be formed from multiple loop coil portions 40a. On the tire cavity surface where the power receiving coil 40 is provided, the tire 10 repeatedly deforms and releases while the tire 10 is rolling. If one power receiving coil 40 is provided around the entire circumference of the tire 10, the power receiving coil 40 will have portions that are distorted by deformation while the tire 10 is rolling (near the contact area of ​​the tire 10) and portions that are not deformed (upper part of the tire 10), making it easier for the power receiving coil 40 to peel off from the tire cavity surface. Therefore, by dividing the circumference of the tire into multiple regions and arranging loop coil portions 40a in each of the divided regions, it is possible to prevent the power receiving coil 40 from peeling off from the tire inner circumferential surface. [Example]

[0123] Below, we will explain the results of manufacturing a tire corresponding to the invention defined in the claims of this application and evaluating the durability of the power receiving coil.

[0124] The tire size was set to 245 / 40R19 (specified by JATMA), and the tire shown in Fig. 1 was produced. The conditions of the tires 10 of Examples 1 to 5 are as shown in Table 1 below. In Table 1, "Fx / SH", "W / SH", "L1 / LC", "L2 / Fx", "L3 / W", "Gb / Ga", "(|S8-S9|) / H", and "θ" conform to the definitions described in this specification. The tires of Examples 1 to 3 thus produced were mounted on wheels with a rim size of 19×8.5J, and the durability and power transmission efficiency of the power receiving coil were evaluated by the methods described below.

[0125] (durability) A running test was started using a drum testing machine under conditions of an air pressure of 220 kPa, a load of 6.6 kN, and an initial speed of 150 km / h. The speed was increased by 5 km / h every 10 minutes, and the speed at which the receiving coil broke or fell off from the inside of the tire was indexed. (power transmission efficiency) For the wireless power transfer system using a tire, the ratio (power transfer efficiency) of power 2 received by the receiving coil (and capacitor resonant circuit) to power 1 transmitted from the transmitting coil was measured, and these ratios were expressed as indexes with Reference Example 1 set to 100. The ratio of power 1 and 2 was measured using a vector network analyzer.

[0126] [Table 1]

[0127] In Examples 1 to 26, compared to Reference Example 1, it was found that durability of the receiving coil was improved by having an "Fx / SH" of 0.12. In Examples 3 to 5, compared to Examples 1 and 2, it was found that superior power supply efficiency was achieved by having an "W / SH" of 0.1 or more and 1.0 or less. In Examples 7 to 9, compared to Examples 3 to 6, it was found that superior power supply efficiency was achieved by having an "L1 / LC" of 0.002 or more and 0.030 or less. In Examples 11 to 13, compared to Examples 1 to 10, it was found that durability of the receiving coil was improved by having an "L2 / Fx" of 0.25 or more and 4.00 or less. In Examples 15 to 17, compared to Examples 11 to 14, it was found that durability of the receiving coil was further improved by having an "L3 / W" of 0.25 or more and 4.00 or less. In Examples 19 to 21, it was found that the durability of the receiving coil was further improved by having "Gb / Ga" of 0.30 or more and 0.80 or less compared to Examples 15 to 18. In Examples 23 to 25, it was found that the durability of the receiving coil was further improved by having "(|S8-S9|) / H" of 0.025 or more and 0.400 or less compared to Examples 19 to 22. In Example 26, it was found that the durability of the receiving coil was further improved by having "θ" of 55° compared to Examples 22 to 25. [Explanation of symbols]

[0128] 10 Tires 11 Tire body 12 Inner liner 13 Tire cavity surface 14 Bead core 16 Bead Filler 18 Carcass 18a Main body 18b Folded part 20 Belt 20a belt layer 20b Belt layer 26 Side tread 30 Cap Tread 34 Tread surface 40 receiving coil 40a Loop coil section 41 Fixing member 41A 1st layer 41B 2nd layer 42 Loop coil section 43,43a,43b,43c,43d,43e,43f Drawer part 43A Proximal end 43B Tip 46 Electronic Circuit Board 46E outer edge 49 First additional reinforcement layer 50 Wireless Power Supply System 51 Second additional reinforcement layer 52 Transmission coil 54 Wheelhouse 56 Power transmission coil unit 58 cases 60 Power transmission surface 62 receiving coil 64 Loop coil section 66 Conductor A Bead part B Sidewall C Shoulder part D Tread

Claims

1. A tire comprising a tread portion provided with a belt, bead portions provided with annular bead cores, a pair of sidewall portions provided between the tread portion and the bead portions, and a power receiving coil that receives power supplied by an AC magnetic field from outside the tire, the power receiving coil has a loop coil portion formed of a loop coil and a lead-out portion connecting the loop coil portion to an electronic circuit board, The loop coil portion is disposed in a side region, the side region is a region in a meridian cross section of the tire between a first perpendicular line drawn from an outer end of the bead core in the tire radial direction to a tire cavity surface in a normal direction of the tire cavity surface, and a second perpendicular line drawn from an outer end of the belt in the tire width direction to the tire cavity surface in a normal direction of the tire cavity surface, The pull-out portion and the belt adjacent region intersect, When the tire cross-sectional height is SH, the belt-adjacent region is an annular region whose outer edge is a position where a second perpendicular line drawn from a side end of the belt in the tire width direction in a direction normal to the tire cavity surface intersects with the tire cavity surface, and whose inner edge is a position spaced apart from the second perpendicular line along the tire cavity surface toward the bead portion by a length Fx expressed by the following formula (1): Fx=0.12×SH...(1)

2. 2. The tire according to claim 1, wherein a distance W in the tire width direction between a base end of the pull-out portion connected to the loop coil portion and a tip end intersecting an outer edge of the electronic circuit board, and a tire cross-sectional height SH satisfy the following formula (2): 0.1≦W / SH≦1.0 (2)

3. 3. The tire according to claim 2, wherein a distance L1 in the tire circumferential direction when a base end of the pull-out portion connected to the loop coil portion and a tip end intersecting an outer edge of the electronic circuit board are projected onto the loop coil portion, and a length LC in the tire circumferential direction of the tread portion satisfy the following formula (3): 0.002≦L1 / LC≦0.030 (3)

4. 4. The tire according to claim 3, wherein a distance L2 in the tire circumferential direction between an intersection of an outer edge of the belt-adjacent region and the pull-out portion and a point obtained by projecting the intersection of an inner edge of the belt-adjacent region and the pull-out portion onto the outer edge of the belt-adjacent region, and the length Fx satisfy the following formula (4): 0.25≦L2 / Fx≦4.00 (4)

5. 2. The tire according to claim 1, wherein a distance L3 in the tire circumferential direction between points obtained by projecting a midpoint between a pair of base ends of the pull-out portion connected to the loop coil portion and a midpoint between a pair of tip ends at a position intersecting an edge of the electronic circuit board onto an imaginary line extending in the tire circumferential direction and passing through an outer edge of the electronic circuit board, and a distance W in the tire width direction satisfy the relationship of the following formula (5): 0.25≦L3 / W≦4.00 (5)

6. 2. The tire according to claim 1, wherein a tire thickness Ga at an outer edge where a lead-out portion 43 of the electronic circuit board installed on the tire cavity surface intersects, and a tire thickness Gb at an inner edge of the belt-adjacent region satisfy the following formula (6): 0.30≦Gb / Ga≦0.80 (6)

7. 5. The tire according to claim 4, wherein a maximum ground contact width H of the tread portion, a ground contact length S8 at a position that is 80% of the maximum ground contact width, and a ground contact length S9 at a position that is 90% of the maximum ground contact width satisfy the following formula (7): 0.025≦(|S8-S9|) / H≦0.400...(7)

8. The tire according to claim 4, wherein the belt includes a steel cord, and an angle θ formed between the steel cord and a conductor of the pull-out portion in a region overlapping the pull-out portion is 55° or less.

9. The tire according to claim 1, further comprising a reinforcing layer for suppressing deformation of the pull-out portion on the outer side in the tire width direction at a location where the belt has only one layer.

10. The tire according to claim 1 , further comprising a second additional reinforcing layer on an outer side of the belt in the tire width direction, the second additional reinforcing layer suppressing deformation of the pull-out portion.

11. The tire according to any one of claims 1 to 10, mounted on a regular rim.

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

13. 13. The wireless power transfer system according to claim 12, wherein at least a portion of the power receiving coil is located within a power transfer region that extends in a winding axis direction of the power transmitting coil across both longitudinal end portions of the power transmitting coil in a tire meridian cross section.

14. 13. The wireless power transfer system according to claim 12, wherein a power transmitting side surface of the power transmitting coil unit including the power transmitting coil that faces the power receiving coil forms an angle with the tire radial direction as viewed from the tire meridian cross section within a range of 70° toward a side closer to the tire and 30° toward a side away from the tire, with an inner end of the power transmitting coil unit in the tire radial direction as a center.

15. The wireless power supply system according to claim 12 , wherein the power transmitting coils are installed within a range of 60° on both sides in the tire circumferential direction about an imaginary line extending vertically upward from the center of the tire.

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