Being the manner which presumes the earth state of the tire which is in the midst of run tire earth

摘要

Provided is a tire contact state estimating method using a tire for estimating a contact state (20) having a block row, in which a plurality of blocks having different lengths in a tire circumference direction are arrayed in the tire circumference direction, and having a tread pattern, in which the kicking ends of two adjacent blocks of the block row are formed at a constant period. The method detects the periodic vibrations, which are generated when the kicking ends to be propagated from the tire (20) to the knuckle (23) leave the road surface sequentially, by an acceleration sensor (11) attached to a knuckle (23), thereby to determine the frequency waveform of the vibrations. The method detects such a vibration level of the frequency waveform in a detection frequency band as is calculated from both a wheel speed (V) measured by a wheel speed sensor (12) and that period, thereby to estimate the grounding state of the tire from the magnitude of that vibration level. Without attaching any sensor to the tire, therefore, the grounding state of the running tire can be highly precisely estimated.