AIR PRESSURE TIRE HAVING BELT LAYERS OF RESPECTIVE THERMAL EXPANSION RATIOS

摘要

PURPOSE: An air pressure tire reduces the stress and improves the durability thereof by having belt layers of respective thermal expansion ratios. CONSTITUTION: A tire belt layer comprises an upper belt layer(10) and a lower belt layer(20). A material having large thermal expansion ratio is used on the upper belt layer(10). A material having small thermal expansion ratio is used on the lower belt layer(20). The thermal expansion ratio of the upper belt layer(10) is larger than that of the lower belt layer(20) by 5 to 40 %. A material having thermal expansion coefficient in 9 to 13 x 10-6 deg.C-1 is used on the upper belt layer(10). A material having thermal expansion coefficient in 7 to 11 x 10-6 deg.C-1 is used on the lower belt layer(20).