| 摘要 |
PROBLEM TO BE SOLVED: To provide a pneumatic run flat tire capable of securing durability against the acute bending of a side wall section in a run flat running state or rim removal. SOLUTION: For a reinforced rubber layer 30A, 100% extension modulus is set to 6 to 20 MPa and the maximum gauge Wmax is set to 4 to 15 mm. A carcass code conforms to ASTM D4974-93. When the reinforced rubber layer 30A is exposed in atmospheric air of 177 deg.C for two minutes with an initial load of 50 g loaded thereon, the heat contraction rate is 13% or less. The gauge of an inner liner 32 is set to 1.5 mm or more within the range of 5 mm inside and outside of the outermost end of the reinforced rubber layer 30A in the radial direction. In such conditions, the carcass code is intensively heat- contracted due to the very high heat generated during run flat running for preventing the standing in a row of bead cores 16 from putting into disorder. This makes it possible to prevent the occurrence of such state that anti rim removal ability in run flat running due to the deterioration of fastening force against a rim 12 cannot be secured. Rubber cracking of an inner liner 32 can also be prevented.
|
