| 摘要 |
<p>There is provided a side-reinforced run flat tire capable of enhancing safety at the time of running with its internal pressure kept in a range of 50 to 150 kPa. A belt-reinforcing layer 8a is made up of a composite cord formed by twisting a high-modulus fiber and a low-modulus fiber together. A stress-strain curve of the composite cord preferably has an inflection point between a low-modulus region, and a high-modulus region, set to fall in a range of 2 to 7 % in strain. In a region of the composite cord, smaller in strain, deformation of a tread is more tolerated than in the case of using a low-modulus cord, and deflection of the sidewall is more deterred than in the case of using the high-modulus cord. Further, when the strain of the composite cord reaches the high-modulus region, the composite cord exhibits modulus of elasticity higher than that in the case of using the low-modulus cord, so that the tread does not undergo excessive deformation such as will occur in the case of using the low-modulus cord. As a result, there will occur enhancement in center ground-contact length as well as durability of the tire when an internal pressure thereof is kept in the range of 50 to 100 kPa, resulting in enhancement in safety at the time of running with the internal pressure kept in the range of 50 to 100 kPa.</p> |
