Patent ID: 7316254
Filing Date: 2008-01-08
Classification: B60C,D07B,Y10S,Y10T

Abstract:
1. A pneumatic tire, comprising a bead portion provided with a bead reinforcing layer, said bead reinforcing layer being made of bead reinforcing cords, each said bead reinforcing cords being made up of seven to twelve metallic filaments whose diameter is in a range of from 0.17 to 0.25 mm and a wrapping wire wound around the filaments and having a diameter in a range of from 0.13 to 0.17 mm, said metallic filaments including at least two waved filaments and at least three unwaved filaments, the waved filament two dimensionally waved before twisted so as to be made up of straight segments in a zigzag formation, all of the waved filaments having the same wave pitch and the same wave height, the wave pitch being in a range of from 10.0 to 35.0 times the diameter of the filament, and the wave height being in a range of from 0.5 to 4.0 times the diameter of the filament, and the value d×h/Pw is in a range of from 0.014 to 0.028, wherein said seven to twelve metallic filaments as a single bunch are final twisted in a direction without all the filaments being twisted first, the final twist pitch for said seven to twelve metallic filaments is in a range of from 10 to 30 mm, at least two, but not all, of the final twisted filaments are intercharged with respect to their relative positions in the final twisted filaments, along a longitudinal direction of the cords, the wrapping wire is wound around the final twisted filaments in a direction reverse to said final twist direction at a winding pitch of 3.0 to 7.0 mm.