| 摘要 |
<p>An improvement in the annular reinforcing structure for radial tires for motor vehicles is disclosed. More specifically, the invention as disclosed provides a pneumatic tire for motor vehicles, specifically for those intended to be used for normal and heavy duty, comprising a carcass and a tread band placed upon it and provided with a reinforcing annular structure, inserted between said carcass and said tread band, comprising at least three layers formed by metal cords substantially as wide as the tread, the two layers arranged in a radially inner position with respect to the third layer being provided with metal cords having an ultimate elongation equal to 3%, said cords being parallel to one another in each layer and crossed with respect to those of the other layer, said cords in said two layers being symmetrically inclined with respect to the longitudinal direction of the tire and forming an angle of value comprised between 5.degree. and 30.degree., the third layer being arranged in a radially outer position and comprising metal cords having an ultimate elongation comprised between 4% and 8%, the cords of said third layer being parallel to one another and arranged according to the longitudinal direction of the tire, characterized by the fact that said third layer consists substantially of a central strip placed astride of the center line and having a width comprised between 40% and 80% of the total width of said layer, and two lateral strips, placed side by side with said central strip, each of said lateral strips showing on its whole a greater resistance to tension and compression stresses than that of said central strip.</p> |
