Abstract: Tread pattern is one of the important factors affecting the noise radiation of truck tires. In this paper, three tires with typical tread pattern are selected to conduct the near-field noise test, with test data analyzed in terms of dispersion and correlation for revealing the differences between the noises at the front and rear ends of tire footprint. The results show that longitudinal groove tire and smooth tire have a better linear correlation between the sound pressure level of noise and speed compared with transverse groove tire, but reasonable design and layout of pattern pitch can significantly improve the linear correlation of transverse groove tire in medium-high speed conditions. The directional noise difference is negatively correlated with the width of transverse groove, but is positively correlated with the width of base surface, while the number of longitudinal groove has less influence on the directional noise difference. The directivity of noise for three typical treads of tires according to the order from weak to strong are transverse groove tire, longitudinal groove tire and smooth tire, with their directional noise difference being 9.5 dB(A), 11dB (A) and 14 dB(A) respectively. The transverse groove and the longitudinal groove are the main causes of that the noise at the rear-end of footprint is louder than that at the front-end of footprint, with their directional noise difference being -0.35 dB(A) and 1.73 dB(A), respectively. The smooth surface is the main cause of that the noise at the rear-end of footprint is quieter than the front-end of footprint, with its directional noise difference being 2.76 dB(A).

Key words: truck tire, noise, radiation characteristics, tread pattern, influence rule