| 摘要 |
PURPOSE:To prevent stones from wedging into a heavy duty tire for busses or the like, by forming a plurality of main grooves in the tread section so that the narrow width of the grooves gradually decreases in the depthwise direction, and by forming a platform on the bottom of each main groove. CONSTITUTION:Zigzagged main grooves G1-G3 are formed in the tread section T of a pneumatic tire. Among these grooves, the main groove G2 is defined by side surfaces (g, g) inclined at an angle alpha of 3-15 deg. so that the width of the groove gradually decreases in the depthwise direction, and a platform P is formed in the bottom of the groove. This platform P is composed of wide width parts PB formed in corner sections and narrow width parts PA formed in the straight sections, the heights Y2, Y3 of the sections PA<PB of the platform P being set to be about 20-60% of the depth Y1 of the groove. Further, the widths S1, S2 of tops of the sections PA, PB are set to be less than the base widths X3, X4 thereof. With this arrangement it is possible to prevent stones from wedging into the tire. |
