| 摘要 |
PROBLEM TO BE SOLVED: To reduce noises by dispersing a rigidity change in the tire circumference in the more uniform direction by setting an amplitude width of a specific degree determined by performing Fourier transform on a sound pressure pulse model for generating a sound pressure pulse at an interval according to pitch arrangement and the length of respective pitches to a specific value or less. SOLUTION: Longitudinal grooves 3 extending in the tire circumferential direction and plural blocks 5 divided by lateral grooves 4 are formed on the tread surface 2. A single pulse sound is generated from a single pitch as a pseudo-model of tire pitch noise, the pulse sound forms a sound pressure level changing according to the length of a pitch, and is successively generated at an interval according to the length of the pitch. Next, pitch arrangement is decided so as to become 2.5 or less in an amplitude width of a degree up to 1 to 10 degrees obtained by performing Fourier transform on a function with such a sound pressure pulse model as a single period. Thus, a rigidity change in a tread is dispersed in the uniform direction to reduce vibration and noise. |
