Patent ID: 7997318
Filing Date: 2011-08-16
Classification: B60C,Y10T

Abstract:
1. A heavy-load tire comprising: a carcass consisting of one carcass ply having a body portion extensive from a tread portion through a side wall portion to a bead core in a bead portion and a turned-up portion which extends from the body portion, which is turned up from an axially inner side to an axially outer side over the bead core, and which has an auxiliary turned-up portion; and a bead reinforcing layer which is disposed at the bead portion and has a reinforcing cord; wherein: the turned-up portion has: a main turned-up portion which curves along an axially inner side, a radially inner side, and an axially outer side of the bead core; and the auxiliary turned-up portion which extends from the main turned-up portion and extends toward the body portion through a vicinity of a radially outer side of the bead core; the bead reinforcing layer has a U-shaped cross section including: an intermediate portion which extends farther radially inwardly than the main turned-up portion and along the main turned-up portion; an outer piece portion which extends from an axially outer side of the intermediate portion and which extends radially outwardly away from the turned-up portion; and an inner piece portion which extends from an axially inner side of the intermediate portion and which extends radially outwardly along the axially inner side of the body portion; the bead portion is provided with a chafer rubber composed of a base portion extending through the radially inner side of the intermediate portion of the bead reinforcing layer to a toe side end portion forming a bead toe end and to a heel side end portion, an inner raised portion extending radially outwardly from the bead toe end, and an outer raised portion extending radially outwardly along the outer piece portion of the bead reinforcing layer from the heel side end portion of the base portion, both the base portion and outer raised portion contacting the bead reinforcing layer; the bead portion is provided with a heel cover layer unified with the outermost side of the base portion of the chafer rubber and the outermost side of the outer raised portion of the chafer rubber, the distance along the outermost side of the base portion of the chafer rubber between the bead toe end and the end of the heel cover layer unified with the outermost side of the base portion of the chafer rubber being 5 mm or more, the heel cover layer continuously extending in the circumferential direction of the tire and being formed of one or more cord plies having an organic fiber cord the entire portion of an outermost side of a heel area defined below; the organic fiber cord of the heel cover layer is arranged at an angle γ of 30 to 90° relative to a circumferential direction of the tire; and the heel area is defined as an area sandwiched between a first straight line extending radially inwardly in a perpendicular manner to a bottom surface of a bead portion from a cross section center of the bead core and a second straight line extending axially outwardly in a perpendicular manner to the first straight line from the cross section center of the bead core.