Bridgestone Corporation

Bridgestone Corportion

Manabu Yanagisawa

Kiyoshi Ikehara

A pneumatic tire comprises a carcass toroidally extending between a pair of bead portions and a belt arranged outside the carcass in a radial direction of the tire and composed of at least one belt layer, in which the belt layer is made from a plurality of steel cords, each cord being formed by twisting 2 to 4 filament bundles each consisting of two steel filaments paralleled with each other so as to have a structure that major axes of the filament bundles constituting the cord are set toward substantially the same direction. In the belt layer, the major axes of the filament bundles in the cords constituting the belt layer are arranged substantially in a row in a widthwise direction of the belt.

Pneumatic tires with specified steel belt cords

A steel cord is disclosed, which has a core-sheath double layer structure having a 2+7 cord construction or a 2+8 cord construction. A twisting direction of the core is the same as that of the sheath, a forming rate Rc of filaments of the core is 103 to 120%, and a forming rate Rs of filaments of the sheath is 102 to 115%. A pneumatic radial tire using such steel cords in a belt layer is also disclosed.

Rubber article-reinforcing steel cords and pneumatic tires using such

A rubber article-reinforcing steel cord includes a core obtained by forming a single filament in a wavy shape, an inner sheath formed by arranging 5 to 6 filaments around the core, and an outer sheath formed by arranging 9 to 12 filaments around the inner sheath. The inner sheath and said outer sheath are twisted together. The diameter of each of the filaments of the inner and outer sheaths is not greater than that of the filaments of the core, 5d .ltoreq.L.ltoreq.3d and 1.2.ltoreq.H.ltoreq.d2.0d in which L and H are a wave length and a wave height of a wave shape of the waved filaments of the core, respectively, and d is a diameter of the filament of the core, and a ratio p.sub.3 /p.sub.2 between the twisting pitch p.sub.2 of the inner sheath and the twisting pitch p.sub.3 of the outer sheath is in a range of 1.4 to 2.5. A heavy duty pneumatic radial tire is also disclosed, which uses such steel cords in a belt.

Steel cords for the reinforcement of rubber articles and heavy duty

A steel cord for reinforcing rubber articles and a pneumatic radial tire having a belt layer using the same, in which the steel cord comprises a core made of a steel filament wave-shaped in a plane (crimped) and turned (curled) and 5-8 sheath filaments wound around the core in the same direction as the turn direction of the core. The wavelength .lambda.c of the core is preferably defined as 8 dc.ltoreq..lambda.c.ltoreq.30 dc when the diameter of the core filament is dc, and the turn-number nc of the core around the center axis of the core per one wave-length of the core is preferably defined as 0.12.ltoreq.nc.ltoreq.0.85 (turn/pitch).

Waved-shaped, curled steel cord for reinforcing rubber articles and

A steel cord is disclosed, which has a core-sheath double layer structure having a 2+7 cord construction or a 2+8 cord construction. A twisting direction of the core is the same as that of the sheath, a forming rate Rc of filaments of the core is 103 to 120% and a forming rate Rs of filaments of the sheath is 102 to 115%. A pneumatic radial tire using such steel cords in a belt layer is also disclosed.

Growing community of inventors

Kodaira, Japan

Manabu Yanagisawa