| 摘要 |
PURPOSE:To monitor the abnormality of a tire at all times and to evade the trouble of battery replacement as much as possible by sending a radio wave from a wheel side unit to a car-body side unit when a signal is sent from the car-body side unit to the wheel side unit or when the abnormality of air pressure of a tire is detected. CONSTITUTION:Wheel side units 3 are equipped with pressure sensors 6 for detecting the air pressure of the tires and provided in the respective wheels of the vehicle, the vehicle-body side unit 4 is provided on the vehicle body, and a two-way communication is made between the both. Namely, the respective wheel side units 3 incorporate power source batteries 13 respectively, a magnetic field communication device 11 is used for a communication from the vehicle- body side unit 4 to the wheel side units 3, and a radio communication device 15 is used for a communication from the wheel side units 3 to the vehicle body side unit 4. Then when a signal is sent from the vehicle-body unit 4 and when the abnormality of air pressure of a tire is detected, the wheel side unit 3 sends a radio wave. Consequently, while abnormality is detected speedily and securely, the consumption of the batteries is suppressed as much as possible. |
