| 摘要 |
PURPOSE:To enhance the operating characteristic and the rate of fuel consumption as well as to make the radial tire light in weight by forming the tire from a coat rubber with specific characteristic in an open twisted construction secured with a specific dia. ratio as the time of no load to at the time of being loaded and by using steel cord having a specified rupture strength. CONSTITUTION:A rubber coated steel cord of a belt layer 3 is made in open twisted construction, wherein the rupture strength F is set within a range where a specific formula is satisfied concerning the number of element wires n and the dia. of an element d, and the ratio of the cord dia. D0 at the time of no load to the dia. D1 when a tension of 30kgf/mm.<2> is applied per unit shall range between 1.05 and 1.40. The 100 modulus of the coating rubber shall range from 35 to 70kgf/cm<2>. This rupture strength F can reduce the weight without impairing the durability. Setting of the degree of dispersion can lead to well penetration of a coating rubber with increased modulus of elasticity into the inter-element spaces and thereby to elimination of voids, which will ensure an enhanced operating characteristic as well as rate of fuel consumption. |
