Patent ID: 7404426

Claim:
A hybrid rubber reinforcement cord comprising fiber strands of two or more kinds having different elastic moduli which are twisted together, wherein at least one higher-modulus fiber strand having a higher elastic modulus is disposed at a center side of the cord and lowermodulus fiber strands having a lower elastic modulus are disposed at a skin side of the cord, wherein the lower-modulus fiber strands are twisted around the at least one higher modulus fiber strand but not twisted around each other at the skin side of the cord, wherein the higher-modulus fiber strand is made of polyparaphenylene benzobisoxazole fiber and the lower-modulus fiber strand is made of glass fiber, wherein a total cross sectional area of the higher-modulus fiber strand is in a range from 10 to 40% of a total cross sectional area of the cord, wherein a twisting rate of the higher-modulus fiber strand is 0-2.0 turns/25 mm; and wherein a twisting rate of the lower-modulus fiber strand is 1.5-3.5 turns/25 mm.