| 摘要 |
PROBLEM TO BE SOLVED: To provide a pneumatic tire improved in run-flat durability without deteriorating rolling resistance and ride comfort during normal travel. SOLUTION: In the pneumatic tire including a pair of side reinforcing rubber layers of a crescent-shaped cross section, at least in part of an area A from a belt end to the maximum width portion of a tire side and an area from the vicinity of a bead core 2 to a bead filler 9, a reinforcing code layer 8 is arranged, which comprises a polyketone fiber code formed by twisting a plurality of filament bundles of polyketone, satisfying a condition of formula (I) σ≥-0.01×E+1.2 and formula (II) σ≥0.02 and coated with coating rubber, and a rubber composition is used as the side reinforcing rubber 7 and/or bead filler rubber, which contains (A) a rubber component and (B) 55 pts.mass or more carbon black based on 100 pts.mass rubber component and has vulcanized rubber physicality in which elasticity modulus at 100% extension (M100) is 10 MPa or more and a Σ value of a tangential loss tanδ at 28-150°C is 6.0 or less. In the formulas (I) and (II), σ represents a thermal contraction stress (cN/dtex) at 177°C, and E represents an elastic modulus (cN/dtex) under a 49N load at 25°C. COPYRIGHT: (C)2010,JPO&INPIT |
