TIGHTNESS MEASURING APPARATUS AND MEASURING METHOD

摘要

According to a method by a frequency analysis of tap tones at the time when a tightness of a ripple member fixed by an elastic force has been tapped by a hammer or a method of detecting a response at the time when the ripple member has been vibrated, an enough precision cannot be obtained for a tightness estimation. A tapping force is applied to a plurality of positions on the member surface, thereby allowing a plurality of tap tones to be generated. Feature amounts are obtained from the plurality of tap tones. An average feature amount is obtained by averaging the feature amounts. The tightness of the ripple member is estimated from the average feature amount by using a correlation between the tightness of the ripple member and the average feature amount.