Abstract: A method and apparatus for detecting the state of wear of the tire tread with accuracy and durability are provided. Acceleration of the inner surface of the tire tread is detected by an acceleration sensor installed in an inner liner region of the tire. From a thus detected time-series waveform of acceleration, an acceleration waveform in the leading edge region including a leading peak which occurs when the block engages with the road surface or an acceleration waveform in the trailing edge region including a trailing peak which occurs when the block disengages from the road surface is extracted. A frequency band value Pf is calculated which is the magnitude of acceleration in a predetermined frequency region of a frequency spectrum obtained through a frequency analysis of the extracted acceleration waveform. And the degree of tire wear is determined by comparing the frequency band value Pf with a preset threshold K(v).

Abstract: A method and apparatus for detecting the state of wear of the tire tread with accuracy and durability are provided. Acceleration of the inner surface of the tire tread is detected by an acceleration sensor installed in an inner liner region of the tire. From a thus detected time-series waveform of acceleration, an acceleration waveform in the leading edge region including a leading peak which occurs when the block engages with the road surface or an acceleration waveform in the trailing edge region including a trailing peak which occurs when the block disengages from the road surface is extracted. A frequency band value Pf is calculated which is the magnitude of acceleration in a predetermined frequency region of a frequency spectrum obtained through a frequency analysis of the extracted acceleration waveform. And the degree of tire wear is determined by comparing the frequency band value Pf with a preset threshold K(v).

Abstract: A vehicle velocity detector 15 is provided, velocity V is detected from position data of the vehicle calculated by using signal from satellites, which is received by a GPS receiver 11 installed to a vehicle body, wheel rotation velocity Vw0 detected by a wheel velocity sensor 12 is corrected in accordance with tire inner pressure detected by a pressure sensor 13 so as to obtain wheel rotation velocity (correction value) Vw, velocity ratio R=(Vw/V), which is ratio of the corrected wheel rotation velocity Vw and the detected wheel velocity V, is calculated and tire wear amount is estimated in accordance with velocity ratio R so that tire wear amount can be measured precisely without processing the tire tread portion.

Abstract: The vibration of a tire 10 of a running vehicle in the circumferential direction or the width direction is detected by a road surface condition estimating tire 10, provided with an acceleration sensor 11 and a signal processing unit 12. Data of a detected vibration waveform are divided into data of three domains, namely, a pre-leading domain, a contact patch domain, and a post-trailing domain, and then the vibration levels in the pre-leading domain and the contact patch domain, respectively, are extracted. At the same time, a vibration component in a low-frequency band and a vibration component in a high-frequency band are extracted respectively from the vibration levels in the respective domains, and respective vibration level ratios R, which are each a ratio thereof, are calculated.