| 摘要 |
PURPOSE:To relax the compressive stress of a crown shoulder section in the cross-sectional direction by forming a stress relaxing groove between the respective ground contact ends under the normal operating load in a crown section and under the larger load than the normal operating load just by a specific rate. CONSTITUTION:At least two circumferential belt layers in are arranged the crown section of a tire 10 and the maximum width of these belt layers is set to the width of approximately 100-140% of the ground width under the normal operating conditions of the crown section. For example, the tire is provided with a carcass layer 11 made of cords arranged at a right angle with the circumferential direction and the belt structure 12 containing a number of circumferential belt layers made of cords arranged almost inparallel to the circumferential direction and a number of circumferential grooves 13 are formed on the ground contact surface of the crown section. In this case, a stress relaxing groove 16 stretching in the circumferential direction is formed between a ground contact end 14 under the normal operating load of the crown section and a ground contact end 15 under the load of approximately 150% of the normal operating load. |
