Patent ID: 8167016
Filing Date: 2012-05-01
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; a bead reinforcing layer which is disposed at the bead portion and has a reinforcing cord; and a bead apex rubber which is disposed farther radially outwardly than the auxiliary turned-up portion of the carcass ply and which extends radially outwardly in a tapering manner, 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 along an axially outer side of the bead apex rubber; 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 reinforcing cord of the bead reinforcing layer has a cord strength of 700 to 1200 N and the reinforcing cord inclines at an angle of 40 to 70° relative to a circumferential direction of the tire at the outer piece portion; the bead apex rubber has: an inner apex portion which is formed of a high complex elasticity modulus rubber and is disposed at a radially inner side; and an outer apex portion which is formed of a rubber whose complex elasticity modulus is lower than that of the rubber of the inner apex portion and is disposed at a radially outer side; the inner apex portion has an L-shaped cross-section including: a bottom piece portion along a radially outer side of the auxiliary turned-up portion; and a raised piece portion which rises at an axially inner end side of the bottom piece portion and extends radially outwardly in a tapering manner along the body portion of the carcass ply; a base line X on the base line X the outer piece portion of the bead reinforcing layer contacts the point P, and both the outer piece portion and inner piece portion of the bead reinforcing layer extend radially outward from the base line X