| 摘要 |
The invention relates to improvements to the endurance of a bead of a radial tyre for a heavy goods vehicle of construction plant type. Such a tyre comprises two beads (1) intended to come into contact with a rim (2), a carcass reinforcement comprising at least one carcass layer (3) comprising a main part (31) wrapped, in each bead (1), from the inside towards the outside of the tyre, around a bead wire (4) to form a turn-up (32), the distance (d) between the turn-up (32) and the main part (31) decreasing continuously, radially towards the outside, from the bead wire (4) and passing through a minimum value (d1), the carcass layer (3) consisting of mutually parallel reinforcers coated in a coating compound (33), a filling element (5) extending axially between the turn-up (32) and the main part (31) and radially towards the outside from the bead wire (4), the filling element (5) comprising at least two filling compounds (51, 52), a first filling compound (51) extending radially outwards from the bead wire (4), the first filling compound (51) having an elastic modulus at 10% elongation at least equal to the elastic modulus of a second filling compound (52). According to the invention, the second filling compound (52) extends, radially outwards, from the bead wire (4) along the turn-up (32) at least as far as the point (A) of the turn-up (32), which point is located at the minimum distance (d1) from the main part (31), and extends at least in part axially outwards, from the first filling compound (51), and the elastic modulus at 10% elongation of the second filling compound (52) is equal to the elastic modulus at 10% elongation of the coating compound (33). |
