| 摘要 |
PURPOSE:To reduce the level of noise from a tire when a vehicle is in running motion for the pneumatic tire having a lug tire pattern, by improving the number of pitches in a tire tread design, groove plane angle , groove width, groove depth, etc. CONSTITUTION:For a pneumatic tire having a lug tire pattern, if assumed a lug groove neighboring to a lug for a minimum unit (1 pitch), the lower level of noise is produced for the smaller number of repeated lugs (number of pitches) circumferentially of the tire. Here in this tire, the number of pitches is formed to 38-46, and each lug groove is diagonally formed at a sloped angle of alpha 5 deg.-15 deg. for a sectional direction of the tire. Further lug groove length l of the lug groove and tread spreading width WT are arranged to the relation of 0.75<l(WT/2)<0.85, and groove depth di at a position in a quarter of the above described width WT and groove depth ds from a shoulder position toward the center of the tire are formed to the relation of 1.15<ds/di<1.30. Still further lug groove width WG is formed to a range of 0.3<WG/lP<0.40 for pitch length lP. |
