Patent ID: 8794283
Filing Date: 2014-08-05
Classification: B60C,Y10T

Abstract:
1. A run-flat tire comprising a radial carcass composed of one or more carcass plies extending toroidally between bead cores embedded in a pair of bead portions, at least one layer of belt arranged at the outer part of the radial carcass in the tire radius direction, and provided with a tread portion arranged at an outer part of a crown portion of the radial carcass in the tire radius direction, a pair of buttress portions positioned at both ends of the tread portion and a pair of side portions connecting the buttress portion and the bead portion, wherein a pair of crescent cross-sectional side reinforcing rubber layers are arranged at the inner part of the radial carcass extending from the buttress portion to the side portion, characterized in that the tire is provided with a reinforcing cord layer adjoining the radial carcass at least from the belt end to the maximum width portion of the tire side portion; cords constituting the reinforcing cord layer are selected from the group consisting of nylon 66 cord, cellulosic fiber cord, polyethylene terephthalate cord, polyethylene naphthalate cord and aramid/nylon 66 hybrid cord, and has a cord angle of less than 10° with respect to the tire radius direction; and the elastic modulus of the cord pulled out from the tire at a temperature of 25° C. under the conditions of a load of 3 N is not higher than 40 cN/dtex, and the thermal shrinkage stress σ (cN/dtex) at a temperature of 177° C. and the elastic modulus E (cN/dtex) at a temperature of 177° C. under the conditions of a load of 10 N satisfy the following conditions: σ+0.025E≧0.36, 40≧E≧8, and σ≧0.05.