Power supply unit, sensor module, tire provided with same, and wireless power transfer system

Abstract

The present invention provides a power supply unit, a sensor module, a tire provided with the power supply unit and the sensor module, and a wireless power transfer system that enable storage of power supplied by a power transmission device outside a tire and enable improvement in impact resistance. This power supply unit is provided with a unit body 11 that integrally houses a power receiving portion 12 for receiving power and a power storage portion 13 for storing the received power. At least a part of the unit body 11 is housed in an elastic body 30, and the elastic body 30 has a modulus M50 of from 0.3 MPa to 10 MPa at 50% elongation.

Description

Power supply unit, sensor module, tire equipped with the same, and wireless power supply system

[0001] The present invention relates to a power supply unit, a sensor module, a tire equipped with the same, and a wireless power supply system, and more particularly to a power supply unit, a sensor module, and a tire equipped with the same that can receive and store power from a power transmission device outside the tire and improve impact resistance, as well as a wireless power supply system.

[0002] Various sensors are installed in the tire cavity to acquire internal tire information such as internal pressure and temperature (see, for example, Patent Documents 1 and 2). Such sensors require an abundant power source to continuously acquire advanced tire information. For example, when a battery is used as the sensor's power source, there is a problem that it is not possible to continuously supply power for a long period of time. Furthermore, when used for a long period of time, the sensor may be damaged depending on the tire's operating environment, so there is a need to adequately protect the sensor.

[0003] Japanese Patent No. 6272225 Publication Japanese Special Table No. 2016-505438

[0004] An object of the present invention is to provide a power supply unit, a sensor module, a tire equipped with the same, and a wireless power supply system that can receive and store power from a power transmission device outside the tire and improve impact resistance.

[0005] In order to achieve the above object, the power supply unit of the present invention comprises a unit body that integrally houses a power receiving section that receives power and a power storage section that stores the received power, at least a part of the unit body is housed in an elastic body, and the modulus M of the elastic body at 50% elongation is 50 is in the range of 0.3 MPa to 10 MPa.

[0006] The sensor module of the present invention includes a module body that integrally houses a power receiving unit that receives power, a power storage unit that stores the received power, and electronic components including a sensor element that detects tire information, and at least a portion of the module body is housed in an elastic body, and the modulus M of the elastic body at 50% elongation is 50 is in the range of 0.3 MPa to 10 MPa.

[0007] Further, a wireless power feeding system of the present invention is a wireless power feeding system including: a tire having the above-described power supply unit or sensor module on its inner surface; a power receiving circuit section disposed as the power receiving section of the power supply unit or the power receiving section of the sensor module and configured to wirelessly receive power; and a power feeding device including a power feeding circuit section configured to wirelessly feed power to the power receiving section, wherein the power feeding circuit section has at least a power feeding coil that generates magnetic flux and supplies power to the power feeding coil to generate magnetic flux, the power receiving circuit section has at least a power receiving coil that receives the magnetic flux emitted from the power feeding coil and recovers energy generated in the power receiving coil by electromagnetic induction, and the power feeding circuit section has a power feeding-side resonance capacitor that forms a parallel resonance circuit in combination with the power feeding coil so as to resonate at a predetermined resonance period; and a control circuit that inputs a drive pulse signal to control on / off of the switch circuit and adjusts the timing of inputting the drive pulse signal, wherein the power receiving circuit unit has a power receiving-side resonance capacitor that forms a resonance circuit in combination with the power receiving coil so as to resonate at a predetermined resonance period, and when the power feeding device is installed in close proximity to a part of the tire and the power receiving unit is located within the power feeding range of the power feeding device, the power feeding device further has a frequency adjustment circuit that appropriately fine-tunes the capacitance of the power feeding-side resonance capacitor or the inductance of the power feeding coil in relation to the distance between the power receiving unit and the power feeding device, and fine-tunes the resonance period of the power feeding device at the timing of inputting the drive pulse signal, thereby appropriately controlling the distance between the power receiving unit and the power feeding device.

[0008] The power supply unit of the present invention includes a unit body that integrally houses a power receiving section that receives power and a power storage section that stores the received power, so that the power receiving section receives power supplied from a power transmitting device outside the tire and the received power can be stored in the power storage section. This makes it possible to use the unit for a long period of time without having to replace batteries as in the past. Furthermore, at least a portion of the unit body is housed in an elastic body, and the modulus M of the elastic body at 50% elongation is 50 Since the stress is in the range of 0.3 MPa to 10 MPa, when the elastic body is deformed, it is possible to appropriately secure the force to maintain the original shape or the force to return to its original shape without breaking, and it is possible to mitigate or absorb the impact, thereby sufficiently protecting the power supply unit, thereby improving the impact resistance of the power supply unit.

[0009] In the power supply unit of the present invention, the inner surface area Ea [mm 2 ] and the outer surface area of ​​the unit body Pa [mm 2 ] preferably satisfies the relationship 0.4≦Ea / Pa. This makes it possible to prevent the power supply unit from being damaged or falling off from the elastic body.

[0010] The sensor module of the present invention includes a module body that integrally houses a power receiving unit that receives power, a power storage unit that stores the received power, and electronic components including a sensor element that detects tire information, so that the power receiving unit receives power supplied from a power transmitting device outside the tire and stores the received power in the power storage unit. This makes it possible to use the module for a long period of time without having to replace batteries as in the past. Furthermore, at least a portion of the module body is housed in an elastic body, and the modulus M of the elastic body at 50% elongation is 100%. 50 Since the stress is in the range of 0.3 MPa to 10 MPa, when the elastic body is deformed, it is possible to appropriately secure the force to maintain the original shape or the force to return to its original shape without breaking, and it is possible to mitigate or absorb the impact, thereby sufficiently protecting the sensor module, thereby improving the impact resistance of the sensor module.

[0011] In the sensor module of the present invention, the inner surface area Ea [mm 2 ] and the outer surface area of ​​the module body Ma [mm 2 It is preferable that the relationship between the elasticity of the sensor module and the elasticity of the elastic body is 0.5≦Ea / Ma. This makes it possible to prevent the sensor module from being damaged or falling off from the elastic body.

[0012] In the power supply unit or sensor module of the present invention, the elongation at break EB [%] of the elastic body at 20°C and the modulus M of the elastic body at 100% elongation 100 It is preferable that the modulus [MPa] satisfies the following formula (1): 1000≧275×M This allows the elongation at break at room temperature and the modulus at high temperature of the elastic body to be properly balanced, and allows for both ease of installation of the power supply unit or sensor module in the elastic body and high-speed durability. 100 -EB ... (1)

[0013] In the tire of the present invention, the tire is provided with the above-mentioned power supply unit or sensor module on its inner surface, and a reinforcing layer including a plurality of steel cords is disposed, the sensor module is disposed in a region of the tire inner surface corresponding to the region of the reinforcing layer, and the ratio of the area of ​​the portion excluding the steel cords to the area of ​​the reinforcing layer in a front view is preferably in the range of 5% to 60%. This allows the power receiving function of the power receiver and the power storing function of the power storing unit to be fully exhibited while ensuring the effects of the reinforcing layer (for example, course retention, external damage resistance, and cornering performance).

[0014] In the tire of the present invention, the tire is equipped with the power supply unit or the sensor module, and the power receiving unit is preferably arranged parallel to the inner surface of the tire. This arrangement is suitable for the power receiving unit to receive power supplied from a power transmitting device outside the tire.

[0015] In the present invention, the modulus at 50% elongation is determined by taking a predetermined rubber test piece (for example, a dumbbell-shaped No. 7) from the elastic body, conducting a tensile test on this rubber test piece at a tensile speed of 500 mm / min in accordance with JIS K6251:2017, and measuring the tensile stress at 50% elongation (MPa:M 50) at room temperature.

[0016] The tire of the present invention is preferably a pneumatic tire, but may also be a non-pneumatic tire. In the case of a pneumatic tire, the interior thereof can be filled with air, an inert gas such as nitrogen, or other gases.

[0017] FIGS. 1(a) and 1(b) show an example of a power supply unit according to an embodiment of the present invention, with FIG. 1(a) being a perspective view of the power supply unit and FIG. 1(b) being a cross-sectional view of the power supply unit. FIGS. 2(a) and 2(b) show an example of a sensor module according to an embodiment of the present invention, with FIG. 2(a) being a perspective view of the sensor module and FIG. 2(b) being a cross-sectional view of the sensor module. FIG. 3 is a meridian cross-section of an example of a pneumatic tire according to an embodiment of the present invention. FIG. 4 is a plan view showing a belt layer disposed in the pneumatic tire of FIG. 3. FIG. 5 is a basic circuit diagram of a wireless power supply system according to an embodiment of the present invention. FIG. 6 is a basic waveform diagram of a power supply device according to the present invention (when SW2 = OFF). FIG. 7 is a basic waveform diagram of a power supply device according to the present invention (when SW2 = ON). FIG. 8 is a configuration diagram of a wireless power supply system according to an embodiment of the present invention.

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in which: Figures 1(a) and 1(b) show a power supply unit according to an embodiment of the present invention.

[0019] 1(a) and 1(b), the power supply unit 10 includes a unit body 11 (housing) that integrally houses a power receiving unit 12 that receives power supplied from a power transmission device (power supply device) outside the tire, and a power storage unit 13 that stores the received power. The unit body 11 has a contact surface 11x that contacts the inner surface of the tire. That is, the contact surface 11x is the surface that contacts the bottom surface of the elastic body 30, which will be described later. This contact surface 11x may be adhered to the elastic body 30, but doing so makes it difficult to replace the power supply unit 10.

[0020] The power receiving unit 12 receives power wirelessly from a power transmitting device (power supply device) outside the tire. The wireless power supply method can be electromagnetic induction. The power receiving unit 12 can be configured, for example, with a coil, a capacitor, a rectifier circuit, etc.

[0021] The power storage unit 13 stores the power received by the power receiving unit 12. A secondary battery can be used as the power storage unit 13. For example, when the power storage unit 13 is connected to a sensor or the like attached to the tire cavity, the power storage unit 13 can supply power to the sensor.

[0022] The power receiving unit 12 and the power storage unit 13 are electrically connected to each other. In particular, it is preferable that the power receiving unit 12 and the power storage unit 13 are stacked in this order from the tire inner surface side.

[0023] In this power supply unit 10, at least a portion of the unit body 11 is housed in an elastic body 30. In other words, the elastic body 30 is a housing for protecting the power supply unit 10. The elastic body 30 includes a flat base 31 that is fixed to the inner surface of the tire, and a cylindrical side wall 32 that protrudes from the base 31.

[0024] The elastic body 30 can be made of, for example, rubber. The elastic body 30 has a modulus M 50 In particular, the modulus M 50 is preferably in the range of 0.5 MPa to 8.0 MPa, and more preferably in the range of 0.5 MPa to 4.0 MPa.

[0025] The power supply unit 10 described above includes a unit body 11 that integrally houses a power receiving section 12 that receives power and a power storage section 13 that stores the received power, so that the power receiving section 12 receives power supplied from a power transmission device outside the tire and the received power can be stored in the power storage section 13. This makes it possible to use the unit for a long period of time without having to replace batteries as in the past. Furthermore, at least a portion of the unit body 11 is housed in an elastic body, and the modulus M of the elastic body 30 at 50% elongation is 50Since the stress is in the range of 0.3 MPa to 10 MPa, when the elastic body 30 is deformed, it is possible to appropriately secure the force that tries to maintain the original shape or the force that tries to return to the original shape without breaking, and it is possible to alleviate or absorb the impact, thereby sufficiently protecting the power supply unit 10. This makes it possible to improve the impact resistance of the power supply unit 10.

[0026] Here, the modulus M of the elastic body 30 50 If the modulus M of the elastic body 30 is less than 0.3 MPa, the force of the elastic body 30 to maintain its original shape will be low, and the effect of improving impact resistance will not be sufficiently obtained. 50 If the elastic modulus exceeds 10 MPa, the flexibility of the elastic body 30 decreases, making it difficult for the elastic body 30 to follow deformation when the tire comes into contact with the ground during rotation. As a result, the cushioning properties of the elastic body 30 decrease, and the impact resistance of the power supply unit 10 tends to decrease.

[0027] In the power supply unit, the inner surface area Ea [mm 2 ] and the outer surface area of ​​the unit body 11 Pa [mm 2 The ratio Ea / Pa preferably satisfies the relationship 0.4≦Ea / Pa, more preferably satisfies the relationship 0.5≦Ea / Pa, and most preferably satisfies the relationship 0.6≦Ea / Pa. As the ratio Ea / Pa increases, the contact area between the elastic body 30 and the power supply unit 10 increases, and the height of the elastic body 30 (side wall portion 32) increases. The upper limit of the ratio Ea / Pa is preferably 2.0 or less, or may be 1.5 or less, or may be 1.0 or less. For example, a second power supply unit (not shown) may be stacked on the unit main body 11. In this case, the outer surface area Pa of the unit main body 11 does not include the outer surface area of ​​the stacked second power supply unit. By appropriately setting the ratio Ea / Pa in this way, damage to the power supply unit 10 and detachment from the elastic body 30 can be prevented. The inner surface area Ea of the elastic body 30 is the inner surface area measured when the power supply unit 10 is housed in the elastic body 30, and can be measured using images of the elastic body 30 and the power supply unit 10 taken using X-rays or CT (Computed Tomography).

[0028] If the ratio Ea / Pa is less than 0.4, when the power supply unit 10 falls off the elastic body 30, the power supply unit 10 may fail due to insufficient protection function.

[0029] 2(a) and 2(b) show a sensor module according to an embodiment of the present invention. As shown in FIGS. 2(a) and 2(b), the sensor module 20 includes a power receiving unit 12 that receives power from a power transmission device (power supply device) located outside the tire, a power storage unit 13 that stores the received power, and a module main body 21 (housing) that houses electronic components 22, including a sensor element that detects tire information. The power receiving unit 12 and the power storage unit 13 are electrically connected, and the power storage unit 13 is electrically connected to the electronic components 22, including the sensor element, and can supply power to the electronic components 22. The module main body 21 has a contact surface 21x that contacts the inner surface of the tire. That is, the contact surface 21x is the surface that contacts the bottom surface of the elastic body 30. While the contact surface 21x may be bonded to the elastic body 30, doing so would make it difficult to replace the sensor module 20.

[0030] 2(a) and 2(b) show an example in which the power receiving unit 12, the power storage unit 13, and the electronic component 22 are stacked in this order from the tire inner surface side, but this is not limited to this and the stacking order can be changed as appropriate depending on the various sensor functions. Furthermore, the electronic component 22 including the sensor element is integrally configured as a sensor unit, and this sensor unit and the power supply unit 10 are combined to configure the sensor module 20.

[0031] The module body 21 has a structure that houses various electronic components 22 therein. The electronic components 22 can be configured to include various sensors, transmitters, receivers, control circuits, and the like for acquiring tire information. Examples of tire information acquired by the sensors include the internal temperature and pressure of the pneumatic tire, the amount of wear and deformation of the tread, and abnormal tire conditions (such as separation failures). For example, a temperature sensor and a pressure sensor are used to measure the internal temperature and pressure. To detect the amount of wear and deformation of the tire tread, for example, a piezoelectric element is provided as a sensor element, which detects an output voltage corresponding to tire deformation during driving, and the amount of tread wear is detected based on the output voltage. Other sensors that can be used include an acceleration sensor, a magnetic sensor, an optical sensor, and a sound sensor (microphone).

[0032] In such a sensor module 20, at least a part of the module body 21 is housed in an elastic body 30. The elastic body 30 housing the module body 21 has a modulus M 50 In particular, the modulus M 50 is preferably in the range of 0.5 MPa to 8.0 MPa, and more preferably in the range of 0.5 MPa to 4.0 MPa.

[0033] The sensor module 20 described above includes a module body 21 that integrally houses the power receiving unit 12 that receives power, the power storage unit 13 that stores the received power, and electronic components 22 that include a sensor element that detects tire information. Therefore, the power receiving unit 12 receives power supplied from a power transmitting device outside the tire and stores the received power in the power storage unit 13. This allows for long-term use without the need for battery replacement as in the past. Furthermore, at least a portion of the module body 21 is housed in an elastic body 30, and the modulus M of the elastic body 30 at 50% elongation is 50Since the stress is in the range of 0.3 MPa to 10 MPa, when the elastic body 30 is deformed, it is possible to appropriately secure the force to maintain the original shape or the force to return to the original shape without breaking, and it is possible to alleviate or absorb the impact, thereby sufficiently protecting the sensor module 20. This makes it possible to improve the impact resistance of the sensor module 20.

[0034] In the above sensor module, the inner surface area Ea [mm 2 ] and the outer surface area Ma [mm 2 The ratio Ea / Ma preferably satisfies the relationship 0.5≦Ea / Ma, more preferably satisfies the relationship 0.7≦Ea / Ma, and most preferably satisfies the relationship 0.8≦Ea / Ma. As the ratio Ea / Ma increases, the contact area between the elastic body 30 and the sensor module 20 increases, and the height of the elastic body 30 (side wall portion 32) increases. The upper limit of the ratio Ea / Ma is preferably 2.0 or less, or may be 1.5 or less, or may be 1.0 or less. For example, a second power supply unit (not shown) or a second sensor unit (not shown) may be stacked on the module main body 21. In this case, the outer surface area Ma of the module main body 21 does not include the outer surface areas of the stacked second power supply unit and second sensor unit. By appropriately setting the ratio Ea / Ma in this way, damage to the sensor module 20 and detachment from the elastic body 30 can be prevented. The inner surface area Ea of the elastic body 30 is the inner surface area measured when the sensor module 20 is housed in the elastic body 30, and can be measured using images of the elastic body 30 and the sensor module 20 taken using X-rays or CT.

[0035] In the elastic body 30 that houses the power supply unit and the sensor module, the elongation at break EB [%] at 20°C and the modulus M at 100% elongation 100 It is preferable that the elongation at break EB at room temperature and the modulus M at high temperature of the elastic body 30 satisfy the relationship of the following formula (1). 100This allows for an appropriate balance between ease of housing the power supply unit 10 or the sensor module 20 in the elastic body 30 and high-speed durability. When housing the power supply unit 10 or the sensor module 20 in the elastic body 30, the physical properties of the elastic body 30 at room temperature (20°C) are relevant, but when the tire rotates, frictional heat is generated between the contact surfaces of the power supply unit 10 or the sensor module 20 and the elastic body 30, which can cause the physical properties of the elastic body 30 to deteriorate and the durability to decrease. Therefore, the elongation at break EB at room temperature and the modulus M at high temperature of the elastic body 30 are also important. 100 It is important to properly balance 1000 ≥ 275 x M 100 -EB ... (1)

[0036] In order to further improve the durability of the elastic body 30, 275×M in the above formula (1) 100 The −EB value is preferably 950 or less, more preferably 800 or less, and most preferably 700 or less. The lower limit may be 100 or more, 200 or more, or 250 or more.

[0037] In addition, the elastic body 30 has an elongation at break EB of 150% or more at 20°C and a modulus M at 100% elongation at 100°C. 100 is preferably 5.0 MPa or less. In particular, the elongation at break EB at 20°C is preferably 160% or more, more preferably 180% or more, even more preferably 200% or more, even more preferably 230% or more, even more preferably 250% or more, even more preferably 280% or more, and even more preferably 300% or more. In addition, the modulus M at 100% elongation at 100°C 100 is preferably 4.9 MPa or less, more preferably 4.7 MPa or less, even more preferably 4.5 MPa or less, even more preferably 4.2 MPa or less, even more preferably 4.0 MPa or less, and even more preferably 3.7 MPa or less. 100The lower limit is more preferably 1.0 MPa or more, even more preferably 1.3 MPa or more, and even more preferably 1.5 MPa or more, since this makes it easier to prevent the housed power supply unit 10 or sensor module 20 from falling off.

[0038] Here, the elongation at break EB at 20°C is a value confirmed by a method in which a predetermined rubber test piece (for example, a dumbbell-shaped No. 7) is taken from the elastic body 30, a tensile test is performed on this rubber test piece at a tensile speed of 500 mm / min in accordance with JIS K6251:2017, and the elongation at break (elongation at break (%): EB) is measured at 20°C. Also, the modulus M at 100% elongation is 100 A predetermined rubber test piece (for example, a dumbbell-shaped No. 7) is taken from the elastic body 30, and a tensile test is carried out on this rubber test piece at a tensile speed of 500 mm / min in accordance with JIS K6251:2017 to measure the tensile stress at 100% elongation (MPa: M 100 ) at 100°C.

[0039] Fig. 3 shows a pneumatic tire according to an embodiment of the present invention. As shown in Fig. 3, the pneumatic tire includes a tread portion 1 extending in the circumferential direction of the tire to form an annular shape, a pair of sidewall portions 2 disposed on both sides of the tread portion 1, and a pair of bead portions 3 disposed radially inward of the sidewall portions 2.

[0040] A carcass layer 4 is mounted between the pair of bead portions 3, 3. This carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction, and is folded back from the inside to the outside of the tire around a bead core 5 disposed in each bead portion 3. A bead filler 6 made of a rubber composition and having a triangular cross section is disposed on the outer periphery of the bead core 5. An inner liner layer 9 is disposed in the region between the pair of bead portions 3 on the tire inner surface Ts. This inner liner layer 9 forms the tire inner surface Ts.

[0041] Meanwhile, multiple belt layers 7 (two layers in FIG. 3 ) are embedded on the outer circumferential side of the carcass layer 4 in the tread portion 1. These belt layers 7 include multiple reinforcing cords that are inclined with respect to the tire circumferential direction, and are arranged so that the reinforcing cords cross each other between the layers. In the belt layers 7, the inclination angle of the reinforcing cords with respect to the tire circumferential direction is set, for example, in the range of 10° to 40°. Steel cords are preferably used as the reinforcing cords of the belt layers 7. At least one belt cover layer 8 is arranged on the outer circumferential side of the belt layers 7, with the aim of improving high-speed durability, and the reinforcing cords are arranged at an angle of, for example, 5° or less with respect to the tire circumferential direction. Organic fiber cords such as nylon and aramid cords are preferably used as the reinforcing cords of the belt cover layer 8.

[0042] The above-described tire internal structure is a typical example of a pneumatic tire, but is not limited to this.

[0043] In the above-described pneumatic tire, at least one power supply unit 10 or sensor module 20 can be attached to the tire inner surface Ts. In this case, it is preferable that the power receiving unit 12 of the power supply unit 10 is disposed parallel to the tire inner surface Ts. In particular, it is more preferable that the power receiving unit 12 is disposed so that the angle between the central axis of the coil inside the power receiving unit 12 and the tire inner surface Ts is 45° to 135°.

[0044] Arranging the power receiving unit 12 in this manner is suitable for the power receiving unit 12 to receive power supplied from a power transmitting device outside the tire. The power receiving unit 12 can be attached to the tire inner surface Ts corresponding to any of the tread portion 1, sidewall portion 2, and bead portion 3. However, if the sensor function is intended to be road surface detection or wear detection, it is desirable to detect the behavior of the tire contact patch, so it is preferable to attach it to the tire inner surface Ts corresponding to the tread portion 1. Furthermore, if fault detection is intended, it is desirable to attach it near the location to be detected, so it can be attached to the tire inner surface Ts corresponding to any location.

[0045] Furthermore, in the above-described pneumatic tire, in addition to the belt layer 7 disposed in the tread portion 1, an additional reinforcing layer including a plurality of steel cords can be disposed in the sidewall portion 2. The power supply unit 10 or the sensor module 20 is disposed in a region of the tire inner surface Ts corresponding to the region where such a reinforcing layer (belt layer 7 or additional reinforcing layer) is disposed. In this case, in a front view of the reinforcing layer (belt layer 7 or additional reinforcing layer), the ratio (×100%) of the area of ​​the portion excluding the steel cords to the area of ​​the reinforcing layer is preferably in the range of 5% to 60%, more preferably in the range of 10% to 45%. This area ratio (void ratio) is calculated by using an image of the reinforcing layer taken from the tire outer surface side using X-rays or CT, extracting a 30 mm square region from the image (for example, region S1 or region S2 shown in FIG. 4 ), and binarizing the image using image processing. For example, in the case of the tread portion 1, either the region S1 in the center portion or the region S2 in the shoulder portion may be used. When the region S2 in the shoulder portion is used, a 30 mm square region is targeted, with one end of the region S2 being a position 5 mm away inward in the tire width direction from the end Ae of the intersection region A between the belt layer 7A on the inner side in the tire radial direction and the belt layer 7B on the outer side in the tire radial direction.

[0046] By setting the area ratio (gap ratio) appropriately in this way, the effects of the reinforcing layer (for example, course retention, damage resistance, and turning ability) can be ensured while the power receiving function of the power receiving unit 12 and the power storing function of the power storing unit 13 can be fully exhibited. Such a reinforcing layer is preferably composed of three layers or less, and more preferably composed of two or three layers.

[0047] If the area ratio is less than 5%, the gaps between the steel cords cannot be sufficiently secured, resulting in a decrease in power supply efficiency. Conversely, if the area ratio is more than 60%, the reinforcing layer may not be effective enough, resulting in a decrease in trackability and resistance to external damage. To improve power supply efficiency, a reinforcing cord made of aramid fiber can be used in the reinforcing layer, but this is not very suitable from the viewpoint of handling stability (trackability, cornering, etc.).

[0048] 3 and 4 show an example in which the sensor module 20 is attached to the tire inner surface Ts of the tread portion 1, but the present invention is not limited to this. For example, when the power supply unit 10 or the sensor module 20 is attached to the tire inner surface Ts of the sidewall portion 2, the void ratio is calculated based on the steel cords of the additional reinforcing layer arranged in the sidewall portion 2, similar to the case of the belt layer 7 described above.

[0049] Next, a wireless power supply system using a parallel resonant circuit according to the present invention will be described. In the wireless power supply system according to the present invention, a power receiving circuit section 700 (described later) can be replaced with the power receiving section 12 of the power supply unit 10 or the power receiving section 12 of the sensor module 20, and a power storage device 74 (described later) can be replaced with the power storage section 13 of the power supply unit 10 or the power storage section 13 of the sensor module 20.

[0050] Fig. 5 shows a basic circuit configuration diagram of a wireless power feeding system 50 according to an embodiment of the present invention. As shown in Fig. 5, the wireless power feeding system 50 is configured by combining a power feeding device 60 and a power receiver 70. Electrical energy is supplied from the power feeding device 60 to the power receiver 70.

[0051] As shown in FIG. 5 , the power receiver 70 is composed of a power receiving coil 71, a power receiving-side resonant capacitor 72, a rectifier circuit 73, a power storage device 74, and a power receiving-side frequency adjustment circuit 75. Both ends of the power receiving coil 71 are connected to the power storage device 74 via the rectifier circuit 73. The power receiving-side resonant capacitor 72 is connected in parallel to the power receiving coil 71. In this case, the resonant capacitor 72 is composed of one or more parallel capacitors. A frequency adjustment circuit 75 is connected between the resonant capacitor 72 and the rectifier circuit 73, and this frequency adjustment circuit 75 adjusts the frequency of the rectifier circuit 73. The power receiving-side frequency adjustment circuit 75 is composed of a frequency adjustment element, which is a capacitor or inductor element, and an FET switching element. Note that if the resonant frequency is constant, the FET switching element is not necessarily required because the resonant frequency can be tuned using the frequency adjustment element during manufacturing.

[0052] There are several characteristic features of the power receiver 70. First, the power receiver 70 is equipped with some kind of power storage device 74. Second, the size, material, and electrical specifications of the power receiving coil 71 provided in the power receiver 70 and the power feeding coil 61 of the power feeding device 60 are designed according to the power feeding range, power feeding distance, and power feeding capacity. Third, the power receiving coil 71 of the power receiver 70 and the resonant capacitor 72 on the power receiving side are configured as a so-called resonator (LC resonant circuit) and are configured with specifications that provide good characteristics at a predetermined resonant frequency. (The same applies to the power feeding coil 61 of the power feeding device 60 and the resonant capacitor 62 of the power feeding device 60.) Fourth, when the power receiver 70 is a parallel resonant circuit, the rectifier circuit may be a half-wave rectifier.

[0053] In the power receiver 70 of this embodiment, the power receiving coil 71, the resonance capacitor 72, the rectifier circuit 73, and the frequency adjustment circuit 75 constitute a power receiving circuit section 700 that recovers energy generated in the power receiving coil 71 by electromagnetic induction. The power receiving circuit section 700 does not include a power storage device 74.

[0054] In the present invention, the allowable deviation of the resonant frequency is large, so that it is possible to realistically deal with the problem of variations in electrical performance of manufactured products, i.e., the problem of yield. Therefore, it is also possible to determine the resonant frequency for each model.

[0055] The power supply device 60 includes a power supply coil 61, a resonance capacitor 62 that forms a resonance circuit together with the power supply coil 61, a switch circuit 63 for turning power on and off to the power supply coil 61, and a control circuit 64 that operates the switch circuit 63. The resonance capacitor 62 on the power supply side is composed of one or more capacitors connected in parallel. A frequency adjustment circuit 65 (e.g., a circuit including a PLL circuit) that creates the on / off timing of the switch is connected to the control circuit 64. The control circuit 64 includes a resonance state sensor 66 that detects the resonance state. This is composed of, for example, a phase detection circuit. A current measurement circuit 67 and a voltage sensor 68 are connected to the resonance state sensor 66. The power supply device 60 also includes a power supply 69 that supplies power to the power supply coil 61 and the necessary power to each circuit.

[0056] The features of the power supply device 60 are as follows. First, the power supply coil 61 and the resonance capacitor 62 form a parallel resonance circuit. Second, there is only one switch circuit. When this switch is turned on, the drive state is established, and when it is turned off, the resonance state is established. Third, a control circuit 64 controls the switch circuit 63 using the timing of a frequency adjustment circuit 65, thereby controlling the timing of the drive state and the resonance state. Fourth, there is a resonance state sensor 66 that detects the resonance state (mainly the frequency deviation), and the control circuit 64 controls to stop power supply or adjust the resonance frequency based on the detection result of the resonance state sensor 66.

[0057] In the power supply device 60 of this embodiment, the power supply coil 61, the resonance capacitor 62, the switch circuit 63, the control circuit 64, the frequency adjustment circuit 65, the resonance state sensor 66, the current measurement circuit 67, and the voltage sensor 68 constitute a power supply circuit section 600 that supplies power to the power supply coil 61 to generate magnetic flux. The power supply circuit section 600 does not include a power source 69.

[0058] FIG. 5 shows a basic circuit diagram (similar to a block diagram). In this basic circuit, a power supply coil 61 generates magnetic flux and causes electromagnetic induction. The electrical circuit of the power supply device 60 includes at least a resonant capacitor 62 and a power source 69, which establish a resonant relationship with the power receiving coil 71 of the power receiver 70 at a fixed frequency. This frequency is called the resonant frequency, and typically uses a long-wave frequency that has minimal effect on the human body. Assuming this is the reference resonant frequency, the reference resonant frequency used in the present invention is not particularly limited. Meanwhile, the resonant frequency of the power supply side and the power receiving side, which will be described later, are normally set to the same resonant frequency. However, an important feature of the present invention is that the resonant frequencies are set to different frequencies based on a predetermined timing.

[0059] The appropriate resonant frequency depends on the distance between the power feeding coil 61 and the power receiving coil 71. The resonant frequency varies slightly depending on the positional relationship and state of the power receiving coil 71 of the power receiver 70. For example, the situation changes depending on the position and tilt of the power receiving coil 71 of the power receiver 70. Therefore, energy can be supplied if the power receiving coil 71 is within the range of the magnetic flux transmitted from the power feeding coil 61. In this case, the coefficient indicating the degree of magnetic coupling between the coil windings is generally called the coupling coefficient (K). The present invention is also characterized by the method for determining the predetermined coupling coefficient that improves power supply efficiency.

[0060] The entry of the receiving coil 71 into the magnetic flux affects the power supply device 60 in the form of a shift in the resonant frequency. A shift in the resonant frequency reduces the efficiency of energy supply. Therefore, the shifted frequency and phase are detected by a resonance state sensor 66 (e.g., a circuit including a phase detection circuit), and the resonant frequency of the power supply coil 61 is adjusted accordingly. For example, this adjustment can be achieved by changing the resonant capacitor 62. This adjustment, also known as tuning, can be performed during manufacturing or automatically controlled during operation using an adjustment circuit, but is collectively referred to as a frequency adjustment circuit. The resonant capacitor is composed of one or more capacitors. The simplest tuning method involves connecting several types of capacitors in parallel in advance, eliminating unnecessary capacitors by pattern cutting during manufacturing, and then adjusting the resonant frequency to a desired frequency. Another method involves manually adjusting the resonant frequency using an adjustment knob using a trimmer capacitor, variable capacitor, or the like.

[0061] In addition, as a method of automatically controlling the frequency during operation using an adjustment circuit, several pairs of capacitors and switches are connected in parallel in advance, and the adjustment circuit controls the switches connected in series to each capacitor to achieve a predetermined resonance frequency. Another method is to attach a servo motor to the adjustment knob of a variable capacitor, and have the adjustment circuit control the servo motor to achieve a predetermined resonance frequency.

[0062] On the other hand, the receiving side is often adjusted during manufacturing, but a method in which the inductance of the receiving coil is measured in advance and a capacitor that matches it is installed in the unused part can also be considered a frequency adjustment circuit in a broad sense.

[0063] Connecting capacitors in parallel reduces internal resistance and further reduces heat generation. Furthermore, the frequency adjustment circuit 65 can adjust the power supply capacity (power) by lengthening or shortening the driving time using, for example, a circuit incorporating a PLL (phase-locked loop) circuit. In some cases, it is also possible to change the resonant frequency by providing multiple power supply coils 61 and switching between them. Here again, a feature of the present invention is that the optimal resonant frequency adjusted by frequency adjustment is a shifted resonant frequency based on a predetermined timing period, which will be described later.

[0064] Various factors must be taken into consideration when adjusting the frequency (or phase). Therefore, it is preferable to provide a control circuit 64 that performs programmatic control using a microcontroller (an integrated circuit including a processor, memory, and peripheral circuits) or a programmable logic device (an integrated circuit that can define and change internal logic circuits). The control circuit 64 is connected to a resonance state sensor 66 (a phase detection circuit). The resonance state sensor 66 detects a frequency or phase shift and transmits a signal to the control circuit 64. As a result, when an object other than the specified power receiver 70 approaches, the resonance state sensor 66 detects an abnormal frequency or phase and transmits a signal to the control circuit 64, which then acts on the power source 69 to stop power supply.

[0065] However, since this system uses a tire in which the steel cords of the above-mentioned reinforcing layer (belt layer 7 or additional reinforcing layer) are embedded, a certain amount of energy loss is detected. Whether or not there is an abnormality is determined on the assumption that the tire is in a predetermined position.

[0066] The wireless power feeding system of the present invention is configured with the basic circuit shown in Fig. 5. The position of the resonant capacitor 62 of the power feeding device 60 is connected in parallel with the power feeding coil 61. A circuit in which this resonant capacitor 62 is arranged is generally called a parallel resonant circuit. On the other hand, a commonly used wireless power feeding system forms a series resonant circuit, and this resonant capacitor is arranged in series with the coil.

[0067] This parallel resonant circuit is characterized in that, when SW1 is turned on and a stable resonant state is established, the power supply device 60 continues to resonate with the power receiver 70 while the energy stored in the receiving coil 71 and the resonant capacitor 72 is released when SW1 is turned off. Here, based on the transition of the resonant state detected by a resonance state sensor 66 connected in parallel with the power supply coil 61, the control circuit 64 realizes power supply at an appropriate frequency through timing control of the drive state by the resonance capacitor and the frequency adjustment circuit 65 (PLL circuit). The resonance state sensor 66 is a sensor that detects the resonant state, and detects transitions in voltage and current and the phase of the resonant frequency, etc.

[0068] A detailed example of the switch circuit 63 in Fig. 5 is composed of an N-channel MOSFET and a Schottky barrier diode. Also, a detailed example of the rectifier circuit 73 of the power receiver 70 is composed of a capacitor, a voltage stabilization circuit 76, and a Schottky barrier diode 77. The Schottky barrier diode 77 may be a rectifier diode. These are just examples, and an appropriate configuration may be used depending on the product specifications.

[0069] A flyback switch is provided to switch between using the Schottky barrier diode that constitutes the switch circuit 63 and short-circuiting it. When the Schottky barrier diode element is used, it is called the "resonance method," and when the Schottky barrier diode element is short-circuited, it is called the "flyback method." The flyback switch FS (SW2) may be provided as an electronic switch for switching, or may be manually shorted using a jumper pin or the like. In some cases, when using only the flyback method, a short pattern may be implemented without implementing a diode.

[0070] The basic waveform diagram of the power supply device in the case of the resonance method (when SW2=OFF) is shown in Fig. 6, which will be described later. In the case of the flyback method, the waveform diagram is shown in Fig. 7, which is a "basic waveform diagram of the power supply device (when SW2=ON)."

[0071] Fig. 6 shows a basic waveform diagram (when SW2 = OFF) of the power supply device according to the present invention. That is, it is a waveform diagram of the resonance method. In Fig. 6, the waveform of the drive current is omitted. Also, the resonance coil current is omitted and only the receiving coil voltage is depicted. The resonance coil voltage is omitted and only the feeding coil voltage is depicted.

[0072] In Fig. 6, there is a drive voltage pulse P1, the pulse waveform for controlling the switch circuit 63, depicted as a rectangular figure. This drive voltage pulse P1 is the waveform of a signal provided to the switch circuit 63 from the control circuit 64 in Fig. 5, and is a pulse generated by the control circuit 64 to control the switch circuit 63 based on the timing of the frequency adjustment circuit 65. When the drive voltage pulse P1 is high, the switch is turned on. In other words, when the switch is on, power from the power source 69 is supplied to the resonance capacitor 62 of the power supply device 60, so that the device is in a driven state. This drive time DT1 (t1) is referred to as the drive pulse width PW1.

[0073] The time when the switch is turned off and not driven is a resonant state, that is, a resonant time. The resonant time RT(t2) is referred to as a resonant period SC1(t2) of the power supply device.

[0074] 5 , when the power supply coil 61 and the resonance capacitor 62 form a parallel resonance circuit, it is safe to say that energy continues to be supplied when the power supply device 60 is in a resonance state with the power receiver 70, whether in a driving state or a resonant state. That is, the frequency adjustment circuit is adjusted so that the resonance period RC1 (t3) on the receiving side satisfies 0.6(t1+t2)≦t3≦1.1(t1+t2), where t3 is the sum of the time (t2) in the resonance state of the power supply device 60 and the time (t1) in the driving state.

[0075] While the switch circuit 63 is turned on, that is, while the drive voltage pulse P1 is being supplied, the power supply coil voltage V1 is kept close to zero (it can be said that the drive voltage pulse P1 is supplied at a timing when the voltage V1 is close to zero). As a result, the power receiving coil voltage V2 exhibits a distorted waveform during the drive time DT1. During the drive time DT1, the power supply coil voltage V1 is zero and a drive current flows. The drive current is a waveform at a point midway from the switch circuit 63 to the resonant capacitor 62 of the power supply device 60 in FIG. 5 . The resonant capacitor 62 of the power supply device 60 appears as an AC waveform that is exactly 90 degrees out of phase with the resonant coil current, but the drive current is a diversion of part of the power energy stored in the resonant capacitor 62.

[0076] When a current flows, the current is converted into magnetic flux output from the power supply coil 61 and acts on the power receiving coil 71 of the power receiver 70, so at this time, it can be said that energy transfer occurs due to electromagnetic induction.

[0077] Once the specifications for the drive pulse width PW1 are determined, the design value of the resonator formed by the power feeding coil 61 of the power feeding device 60 and the resonant capacitor 62 of the power feeding device 60, i.e., the resonant frequency, can be determined. The resonant frequency of the power feeding device 60 is determined by the periodic time of the resonant period SC1 of the power feeding device 60. On the other hand, the resonant frequency of the power receiver 70 is determined by the periodic time of the resonant period RC1 on the power receiving side, which is the sum of the periodic times of the drive pulse width PW1 and the resonant period SC1 of the power feeding device 60. Therefore, a feature of the present invention is that the resonant frequency of the power feeding device 60 and the resonant frequency of the power receiver 70 are adjusted to have a predetermined deviation.

[0078] In this invention, the magnetic flux from the power supply device must pass through the steel cords in the reinforcing layer embedded in the tire to reach the receiving coil of the power receiver, and this coupling must be small. Properly determining this coupling coefficient is also an important factor. It is preferable to set the coupling coefficient K to a value in the range of 0.3 (30%) or less or close to that range. A weak coupling can be achieved by adjusting the size, number of turns, and inductance of the power supply coil and the receiving coil. For example, if the coupling coefficient measured at the required power supply distance between the power supply coil and the receiving coil is too weak, the coupling coefficient can be increased by, for example, increasing the size (inner diameter) of the receiving coil or the number of turns. In particular, a power supply efficiency range in which energy can be efficiently transmitted is approximately K = 0.05 to 0.3 (5% to 30%). Conversely, the specifications of the drive pulse width, the power supply coil and the receiving coil, the power supply range, and the power supply distance can be determined to achieve this coupling coefficient.

[0079] Furthermore, the coupling coefficient is closely related to the power supply distance. The higher the coupling coefficient, the higher the power supply efficiency. The position where power supply efficiency is high occurs when the power supply distance is zero. The closer the distance between the power supply coil and the power receiving coil, the higher the coupling coefficient, and the farther it is, the lower the coupling coefficient becomes. In this invention, power supply efficiency is high when the coupling coefficient is relatively low, around K = 0.05 to 0.3 (5% to 30%), so high power supply efficiency can be achieved when the power supply coil and the power receiving coil are spaced a certain distance apart.

[0080] FIG. 7 shows the basic waveform diagram of the power supply device according to the present invention (when SW2 is ON). That is, it is a waveform diagram of the flyback system. When SW2 is ON, the diode is short-circuited, and the flyback system is used. Compared to the waveform of the resonant system when SW2 is OFF, the power supply coil voltage V3 appears only in the positive direction. The drive pulse width PW2 and drive time DT2 can be lengthened. Basically, they can be set to a maximum of slightly less than half a cycle of the resonant cycle SC2 of the power supply device.

[0081] The longer the drive time (drive pulse width), the more current flows through the coil, generating magnetic flux in the power supply coil 61. This magnetic flux also passes through the power receiving coil 71 of the power receiver 70 in a resonant state, causing current to flow. However, it cannot be said that simply setting the drive voltage pulse P2 to the full half cycle is sufficient. After a certain time (width), the power supply capacity reaches its limit. Therefore, making the pulse slightly shorter than half the cycle improves power supply efficiency.

[0082] In the case of the flyback system, the relationship between the resonant period of the power supply device and the resonant period of the receiving side is not such that the sum of the resonant time and the drive time is the resonant period of the receiving side, but it is sufficient to set the optimum value of a simulation performed using the resonant system so that 0.6(t1+t2)≦t3≦1.1(t1+t2) holds for the time (t1+t2) obtained by adding up the time in the resonant state (t2) and the time in the drive state (t1). Alternatively, the interval between drive voltage pulses P2 becomes the resonant period SC2 of the power supply device, and this can be adjusted to match the resonant period RC2 of the receiving side.

[0083] FIG. 8 shows a configuration diagram of a wireless power supply system according to an embodiment of the present invention. The tire T includes a built-in power receiver 70. The tire T is rotatable. For example, the tire T may be mounted on a vehicle or a dedicated device. The power supply device 60 is installed in a predetermined location, but is positioned so that the power receiver 70 is within its power supply range, i.e., close to the tire T. As the tire T rotates, the power receiver 70 approaches the power supply device 60, causing a current change in the current measurement circuit 67, such as a current value At measured by the current measurement circuit. Furthermore, a voltage change in the voltage sensor 68, such as a voltage value Vt measured by the voltage sensor, occurs. The control circuit 64 detects and determines this, and notifies the tire T of the approach of the power receiver 70 using a predetermined communication means or a light or sound notification function. The tire T is then fixed in place, allowing the power receiver 70 to efficiently wirelessly charge the battery built into the tire T.

[0084] Furthermore, the tire T has a reinforcing layer of steel cords Sc embedded therein, which obstructs the magnetic flux and results in energy loss. At this time, a constant current value is observed in the current measurement circuit 67. A constant voltage value is also observed in the voltage sensor 68. The control circuit 64 detects the energy loss based on changes in the measured current value of the current measurement circuit 67 and the voltage value of the voltage sensor 68. This makes it possible to determine whether the tire T is in a predetermined position. For example, the tire T may be detected as having entered the power supply range of the power supply device (arrived at a predetermined position), and this may be notified by a predetermined communication means or by light or sound. Then, the tire T may be rotated, and as described above, notification may be given that the power receiver 70 has approached (the power receiver 70 has entered the power supply range of the power supply device 60), and the power receiver 70 may wirelessly charge the battery.

[0085] Although the explanation has been given in which the power supply device is fixed and the tire rotates, the same method can also be used in the opposite case, where the tire is fixed and the power supply device is operated to rotate around the tire's circumference, and in the same way, the receiver detects whether it has entered the power supply range.

[0086] The tire size is 225 / 45R18, and the power supply unit has a unit body that integrally houses a power receiving unit and a power storage unit, and at least a part of the unit body is housed in an elastic body, and the elastic body is fixed to the inner surface of the tire, and the modulus M 50 The tires of Comparative Example 11 and Examples 11 to 15 were manufactured with the ratio Ea / Pa set as shown in Table 1.

[0087] These test tires were evaluated for the feasibility of power supply using the following test method, and the results are shown in Table 1.

[0088] Each test tire was mounted on a wheel with a rim size of 18 x 7.5J, and a running test was conducted using a drum testing machine under the following conditions: air pressure of 230 kPa, load weight of 4.5 kN, running speed of 81 km, and running distance of 15,000 km. Then, power was supplied from the outside of the tire using a power transmission device to check whether the power supply unit could supply power. The evaluation results were indicated as "D (unacceptable)" if power could not be supplied, and "C (acceptable)" if power could be supplied. Furthermore, if power could be supplied even when the running distance was extended to twice the above running distance, it was indicated as "B (good)," if power could be supplied even when the running distance was extended to three times the above running distance, it was indicated as "A (excellent)," and if power could be supplied even when the running distance was extended to four times the above running distance, it was indicated as "AA (excellent)."

[0089]

[0090] As can be seen from Table 1, it was confirmed that the tires of Examples 11 to 15 were able to extend the distance over which power could be supplied compared to Comparative Example 11. This shows that the power supply unit was adequately protected by the elastic body, and impact resistance was improved.

[0091] The tire size is 225 / 45R18, and the sensor module has a module body that integrally houses a power receiving unit, a power storage unit, and electronic components including a sensor element, and at least a part of the module body is housed in an elastic body, and the elastic body is fixed to the tire inner surface, and the modulus M 50 The tires of Comparative Example 21 and Examples 21 to 26 were manufactured with the ratio Ea / Ma set as shown in Table 2.

[0092] These test tires were evaluated for the feasibility of power supply using the following test method, and the results are shown in Table 2.

[0093] Each test tire was mounted on a wheel with a rim size of 18 x 7.5J, and a running test was conducted using a drum testing machine under the following conditions: air pressure of 230 kPa, load weight of 4.5 kN, running speed of 81 km, and running distance of 15,000 km. Then, power was supplied from the outside of the tire using a power transmission device to check whether the sensor module could supply power. Cases where power could not be supplied were indicated as "D (unacceptable)," and cases where power could be supplied were indicated as "C (acceptable)." Furthermore, cases where power could be supplied even when the running distance was extended to twice the above running distance were indicated as "B (good)," cases where power could be supplied even when the running distance was extended to three times the above running distance were indicated as "A (excellent)," and cases where power could be supplied even when the running distance was extended to four times the above running distance were indicated as "AA (excellent)."

[0094]

[0095] As can be seen from Table 2, it was confirmed that the tires of Examples 21 to 26 were able to extend the distance at which power could be supplied compared to Comparative Example 21. This shows that the sensor module was adequately protected by the elastic body, and impact resistance was improved.

[0096] Furthermore, elastic bodies having the compositions shown in Table 3 below and the shapes shown in FIG. 2 were mounted on tires having a tire size of 225 / 45R18. For the tires of Reference Example 31 and Examples 31 to 35 obtained, the modulus M of the elastic body at 100% elongation was measured as follows. 100 The elongation at break (EB) at 20°C was measured, and an indoor durability test was carried out.

[0097] Modulus M at 100% elongation 100 A dumbbell-shaped No. 7 rubber test piece (thickness 1.0±0.1 mm) was taken from the elastic body of each tire obtained, and a tensile test was carried out on this rubber test piece at a tensile speed of 500 mm / min in accordance with JIS K6251:2017 to measure the tensile stress at 100% elongation (MPa:M 100 ) was measured at 100° C. The results are shown in the middle of Table 3.

[0098] Elongation at break EB at 20°C: A dumbbell-shaped No. 7 rubber test piece (thickness 1.0±0.1 mm) was taken from the elastic body of each obtained tire, and a tensile test was performed on this rubber test piece at a tensile speed of 500 mm / min in accordance with JIS K6251:2017 to measure the elongation at break (elongation at break (%): EB) at 20°C. The results are shown in the middle of Table 3.

[0099] Indoor durability test: Each tire was fitted with a sensor module using a piezoelectric element as the sensor element and mounted on an elastic body. The tire was then pre-treated by injecting 350 kPa of oxygen into the tire and storing it at 80°C for five days. The tire was then mounted on a wheel and subjected to an indoor running test using a drum tester, with the running speed increasing by 10 km / h every two hours from 81 km / h. The speed at which the elastic body broke was used as the evaluation result. Breakdown of the elastic body was defined as a state in which the sensor module was no longer able to perform its sensing function due to cracking or detachment of the elastic body. The results are shown in the lower part of Table 3. Examples 31 to 35 were expressed as an index, with the value of Reference Example 31 being 100.

[0100]

[0101] The details of each component in Table 3 are as follows: NR: Natural rubber (STR20, manufactured by Bondit) BR: Butadiene rubber (Nipol BR1220, manufactured by Nippon Zeon Co., Ltd.) CB1: Carbon black (Showblack N330, nitrogen adsorption specific surface area (NSA): 71 m 2 / g, manufactured by Cabot Japan Co., Ltd.) CB2: Carbon black (Show Black N660, nitrogen adsorption specific surface area (NSA): 34 m 2 / g, manufactured by Cabot Japan Co., Ltd.) Oil: aroma oil (Diana Process NH-70S, manufactured by Idemitsu Kosan Co., Ltd.) Zinc oxide: zinc oxide (Ginrei R, manufactured by Toho Zinc Co., Ltd.) Stearic acid: Kiri Stearic Acid Beads (manufactured by Chiba Fatty Acid Co., Ltd.) Anti-aging agent: 6PPD (manufactured by Flexis Co., Ltd.) Sulfur: Sulfax 5 (manufactured by Tsurumi Chemical Industry Co., Ltd.) Vulcanization accelerator: Noccela DM-PO (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.)

[0102] As can be seen from Table 3, the tires of Examples 33 to 35 had improved high-speed durability compared to Reference Example 31. The tires of Examples 31 and 32 did not deteriorate in high-speed durability compared to Reference Example 31, and maintained the high-speed durability.

[0103] Tires of Examples 41 to 46 were manufactured using 225 / 45R18 tires having the basic structure illustrated in FIG. 3, with an elastic body having the shape shown in FIG. 2 attached to the inner surface of the tire while accommodating a sensor module, and with different gap ratios of the steel cords constituting the belt layers and different numbers of belt layers as shown in Table 4.

[0104] These test tires were evaluated for steering stability and whether or not they could be powered by the following test methods. The results are shown in Table 4.

[0105] Steering stability: Each test tire was mounted on a wheel with a rim size of 18 x 7.5J, mounted on a test vehicle (engine displacement 2000cc), and the air pressure was set to 230 kPa. A test driver performed a sensory evaluation of steering stability on a paved test course. The evaluation results were scored on a 10-point scale with 5 being the standard. The higher the score, the better the steering stability.

[0106] Power supply feasibility: Power was supplied from the outside of the tire using a power transmission device to check whether the sensor module could supply power. The evaluation results were indicated as "○ (possible)" if power could be supplied, and "× (not possible)" if power could not be supplied.

[0107]

[0108] As can be seen from Table 4, power could be supplied to all of the tires of Examples 41 to 46. In particular, the tires of Examples 41 to 44 had higher driving stability than the reference point and had excellent driving stability.

[0109] REFERENCE SIGNS LIST 1 tread portion 2 sidewall portion 3 bead portion 10 power supply unit 11 unit body 12 power receiving portion 13 power storage portion 20 sensor module 21 module body 22 electronic component 30 elastic body 31 base portion 32 sidewall portion 50 wireless power feeding system 60 power feeding device 70 power receiver Ts tire inner surface CL tire center line

Claims

1. A unit body is provided which integrally houses a power receiving part for receiving electric power and a power storage part for storing the received electric power, and at least a part of this unit body is housed in an elastic body, and the modulus M at 50% elongation of the elastic body is 50 is in the range of 0.3 MPa to 10 MPa.

2. The inner surface area Ea [mm 2 ] and the outer surface area of ​​the unit body Pa [mm 2 2. The power supply unit according to claim 1, wherein the relationship between Ea and Pa satisfies 0.4≦Ea / Pa.

3. The elongation at break EB [%] of the elastic body at 20°C and the modulus M of the elastic body at 100% elongation 100 3. The power supply unit according to claim 1, wherein the relationship between the axial length of the power supply and the pressure in the power source is expressed by the following formula (1): 1000 ≥ 275 × M [MPa] 100 -EB ... (1) 4. A module body is provided which integrally houses a power receiving unit for receiving electric power, a power storage unit for storing the received electric power, and electronic components including a sensor element for detecting tire information, and at least a part of the module body is housed in an elastic body, and the modulus M at 50% elongation of the elastic body is 50 The sensor module is characterized in that the resistance is in the range of 0.3 MPa to 10 MPa.

5. The inner surface area Ea [mm 2 ] and the outer surface area Ma [mm 2 5. The sensor module according to claim 4, wherein Ea / Ma satisfies the relationship 0.5≦Ea / Ma.

6. The elongation at break EB [%] of the elastic body at 20°C and the modulus M of the elastic body at 100% elongation 100 6. The sensor module according to claim 4, wherein the relationship between the tensile strength and the resistivity [MPa] satisfies the following formula (1): 1000≧275×M 100 -EB ... (1) 7. A tire equipped with the power supply unit according to any one of claims 1 to 3 on its inner surface, wherein a reinforcing layer containing a plurality of steel cords is disposed, the power supply unit is disposed within an area of ​​the tire's inner surface corresponding to the area of ​​the reinforcing layer, and the ratio of the area of ​​the reinforcing layer excluding the steel cords to the area of ​​the reinforcing layer when viewed from the front is in the range of 5% to 60%.

8. A tire equipped with a sensor module according to any one of claims 4 to 6 on its inner surface, wherein a reinforcing layer containing a plurality of steel cords is arranged, the sensor module is arranged in an area of ​​the tire inner surface corresponding to the area where the reinforcing layer is arranged, and the ratio of the area of ​​the part excluding the steel cords to the area of ​​the reinforcing layer in a front view of the reinforcing layer is in the range of 5% to 60%.

9. A tire equipped with the power supply unit according to any one of claims 1 to 3, characterized in that the power receiving section is disposed parallel to the inner surface of the tire.

10. A tire equipped with a sensor module according to any one of claims 4 to 6, wherein the power receiving section is disposed parallel to the inner surface of the tire.

11. A wireless power supply system comprising: a tire having a power supply unit according to any one of claims 1 to 3 or a sensor module according to any one of claims 4 to 6 on its inner surface; a power receiving circuit section disposed as the power receiving section of the power supply unit or the power receiving section of the sensor module and receiving power wirelessly; and a power supply device including a power supply circuit section that wirelessly supplies power to the power receiving section, wherein the power supply circuit section has at least a power supply coil that generates magnetic flux and supplies power to the power supply coil to generate magnetic flux; the power receiving circuit section has at least a power receiving coil that receives magnetic flux emitted from the power supply coil and recovers energy generated in the power receiving coil by electromagnetic induction; the power feeding circuit unit has a power feeding-side resonance capacitor that forms a parallel resonance circuit in combination with the power feeding coil so as to resonate at a predetermined resonance period, a switch circuit that realizes a switch-on state in which a drive current flows to the power feeding coil and a switch-off state in which the drive current is cut off, and a control circuit that inputs a drive pulse signal that controls on / off of the switch circuit and adjusts the timing of input of the drive pulse signal; the power receiving circuit unit has a power receiving-side resonance capacitor that forms a resonance circuit in combination with the power receiving coil so as to resonate at a predetermined resonance period, when the power feeding device is installed in close proximity to a part of the tire and the power receiving unit is located within the power feeding range of the power feeding device, and further comprises a frequency adjustment circuit that appropriately controls the distance between the power receiving unit and the power feeding device by appropriately fine-tuning the capacitance of the power feeding-side resonance capacitor or the inductance of the power feeding coil in relation to the distance between the power receiving unit and the power feeding device and fine-tuning the resonance period of the power feeding device at the timing of input of the drive pulse signal.

12. The wireless power transfer system according to claim 11, wherein the coupling obtained by adjusting the sizes, number of turns, and inductance of the power transfer coil and the power receiving coil so that the coupling coefficient K between the power transfer coil and the power receiving coil is in the range of K = 0.3 or less allows magnetic flux to pass through the steel cord of the reinforcing layer embedded in the tire.

13. A wireless power supply system according to claim 11 or 12, characterized in that the power supply circuit section has a current measurement circuit that measures the current flowing in the power supply coil and a voltage sensor, the tire is in a rotating state, the power supply device is installed in close proximity to a part of the tire, the current measurement circuit measures changes in current, the voltage sensor measures changes in voltage, and these measured measurement information are input to the control circuit, and when the power receiving unit enters the power supply range of the power supply device as the tire rotates, the control circuit detects that the power receiving unit is within the power supply range of the power supply device based on changes in the current value of the current measurement circuit and changes in the voltage value of the voltage sensor, the control circuit has a function of notifying by a predetermined communication means or by light or sound.

14. The wireless power supply system according to claim 11 or 12, wherein the power supply circuit section includes a current measurement circuit that measures the current flowing in the power supply coil and a voltage sensor, the power supply device is in a state of rotating around the circumference of the tire, the power supply device is installed in close proximity to a part of the tire, the current measurement circuit measures changes in current, the voltage sensor measures changes in voltage, and these measured measurement information are input to the control circuit, and when the power receiving unit enters the power supply range of the power supply device as the power supply device rotates around the circumference of the tire, the control circuit has a function of notifying by a predetermined communication means or by light or sound when it detects that the power receiving unit is within the power supply range of the power supply device based on changes in the current value of the current measurement circuit and changes in the voltage value of the voltage sensor.

15. A wireless power supply system according to claim 11 or 12, characterized in that the power supply circuit section has a current measurement circuit that measures the current flowing through the power supply coil and a voltage sensor, the power supply device is installed in a location close to a part of the tire, the current measurement circuit measures changes in current, the voltage sensor measures changes in voltage, and these measured measurement information are input to the control circuit, and when the tire comes within the power supply range of the power supply device, the control circuit detects energy loss due to steel cords in a reinforcing layer embedded in the tire based on changes in the current value of the current measurement circuit and the voltage value of the voltage sensor, and when it detects that the tire is in a predetermined position, it notifies the system by a predetermined communication means or by light or sound.

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