Tire sensor system and tire used for the same
View Patent ↗Electromagnetic field transmissions between a sensor unit mounted on the inside surface of a tire and a sensor control unit mounted on the vehicle body are attenuated by the wall surface of a tire disposed between the units, and sensitivity is reduced. A booster antenna ( 18 ) is embedded in the tire wall surface between the sensor unit ( 6 ) and the sensor control unit ( 10 ). The booster antenna ( 18 ) is a coil antenna, and is configured so that the resonance frequency, which corresponds to the impedance and capacitance component of the booster antenna coil, corresponds to the frequency f 0 of the transmission electromagnetic field of the sensor control unit ( 10 ). The booster antenna ( 18 ) is disposed in a position in which a magnetic coupling is formed with the coil antenna of the sensor unit ( 6 ), and transmissions via the electromagnetic field between the sensor unit ( 6 ) and the sensor control unit ( 10 ) are carried out through the booster antenna ( 18 ).
1. A tire sensor system in which a control unit disposed in a vehicle body and a sensor unit disposed inside a tire attached to the vehicle body are wirelessly connected, the tire sensor system comprising:
a plurality of booster antennas embedded in the material constituting the tire; wherein
the control unit generates a transmission electromagnetic field that varies with time and senses electromagnetic field fluctuations produced by the sensor unit;
the sensor unit comprises:
a sensor for measuring a predefined target value in the tire,
a response circuit for generating transmission alternating current modulated in accordance with the output of the sensor, and
a primary coil antenna for generating electromagnetic field fluctuations on the basis of the transmission alternating current;
wherein the plurality of booster antennas constitutes secondary coil antennas lined up along a circumference of the tire,
the plurality of booster antennas are arranged so that a coil face of a first booster antenna partially overlaps a coil face of a second booster antenna, the coil face of the second booster antenna partially overlaps the coil face of the first booster antenna and a coil face of a third booster antenna, and the coil face of the third booster antenna does not partially overlap the coil face of the first booster antenna,
coil faces of the plurality of booster antennas are sequentially interlinked with each other via magnetic; coupling, and
at least one of the plurality of booster antennas is directly magnetically coupled to the primary coil antenna.
2. The tire sensor system of claim 1 , wherein the plurality of booster antennas is arranged around an entire circumference of the tire.
3. The tire sensor system of claim 1 , wherein the booster antennas have resonance characteristics that correspond to a fluctuation frequency of the transmission electromagnetic field.
4. The tire sensor system of claim 1 , wherein the primary coil antenna converts variation in the transmission electromagnetic field into drive power of the sensor unit.
5. The tire sensor system of claim 1 , wherein the sensor is an inflation pressure sensor for measuring air pressure in the tire.
6. A tire in which a sensor unit for generating electromagnetic field fluctuations in accordance with a transmission electromagnetic field from the exterior is disposed in the space inside the tire, the tire comprising:
a plurality of booster antennas embedded in the material constituting the tire; wherein
the sensor unit comprises:
a sensor for measuring a predefined target value in the tire,
a response circuit for generating transmission alternating current modulated in accordance with the output of the sensor, and
a primary coil antenna for generating electromagnetic field fluctuations on the basis of the transmission alternating current;
wherein the plurality of booster antennas constitutes secondary coil antennas lined up along a circumference of the tire,
the plurality of booster antennas are arranged so that a coil face of a first boost antenna partially overlaps a coil face of a second booster antenna, the coil face of the second booster antenna partially overlaps the coil face of the first booster antenna and a coil face of a third booster antenna, and the coil face of the third booster antenna does not partially overlap the coil face of the first booster antenna,
coil faces of the plurality of booster antennas are sequentially interlinked with each other via magnetic coupling, and
at least one of the plurality of booster antennas is directly magnetically coupled to the primary coil antenna.
7. The tire of claim 6 , wherein the plurality of booster antennas is arranged around an entire circumference of the tire.
8. The tire of claim 6 , wherein the booster antennas have resonance characteristics that correspond to a fluctuation frequency of the transmission electromagnetic field.
9. The tire of claim 6 , wherein the primary coil antenna converts variation in the transmission electromagnetic field into drive power of the sensor unit.
10. The tire of claim 6 , wherein the sensor is an inflation pressure sensor for measuring air pressure in the tire.