ANNULAR REINFORCING STRUCTURE FOR RADIAL TIRES

摘要

ABSTRACT OF THE DISCLOSUREAn improvement in the annular reinforcing structurefor radial tires for motor vehicles is disclosed. Morespecifically, the invention as disclosed provides apneumatic tire for motor vehicles, specifically for thoseintended to be used for normal and heavy duty, comprising acarcass and a tread band placed upon it and provided with areinforcing annular structure, inserted between said carcassand said tread band, comprising at least three layers formedby metal cords substantially as wide as the tread, the twolayers arranged in a radially inner position with respect tothe third layer being provided with metal cords having anultimate elongation equal to 3%, said cords being parallelto one another in each layer and crossed with respect tothose of the other layer, said cords in said two layers beingsymmetrically inclined with respect to the longitudinaldirection of the tire and forming an angle of value comprisedbetween 5° and 30°, the third layer being arranged in aradially outer position and comprising metal cords having anultimate elongation comprised between 4% and 8%, the cordsof said third layer being parallel to one another andarranged according to the longitudinal direction of the tire,characterized by the fact that said third layer consistssubstantially of a central strip placed astride of the centerline and having a width comprised between 40% and 80% of thetotal width of said layer, and two lateral strips, placedside by side with said central strip, each of said lateralstrips showing on its whole a greater resistance to tensionand compression stresses than that of said central strip.