Bridgestone Corporation

Bridgestone Metalpha Corporation

Takaya Yamanaka

Eiji Kudo

Takahiro Kimura

Hiroyuki Kato

A pneumatic tire comprises a carcasscomprised of one or more carcass plies toroidally extending between a pair of bead portions, a tread rubberarranged at an outer peripheral side of a crown portion of the carcassa beltarranged between the tread rubberand the carcassand comprised of two belt layerscordsof which layers being crossed with each other and extending in an inclination angle of 45-80&#xb0; with respect to a circumferential direction of the tire, and one or more circumferential strengthening layersarranged at an inner peripheral side of the beltand containing wavy or zigzag cordsextended substantially in the circumferential direction of the tire, in which a width L of a belt layerlocated at the inner peripheral side is made larger than a width M of the circumferential strengthening layer and a width N of a belt layer located at the outer peripheral side is made smaller than the width M of the circumferential strengthening layer.

Pneumatic tire

A pneumatic tire comprises a tread portion, a pair of sidewall portions and a pair of bead portions and a radial carcass of at least one rubberized carcass ply containing steel cord therein and wound around the bead core to form a part or a whole of a wound portion of the carcass ply as a wind contact part along the peripheral face of the bead core, wherein at least one steel cord reinforcing layer is arranged in the bead portion.

Pneumatic tires

A steel cord for the reinforcement of rubber articles has a two-layer construction in which a core consists of two steel filaments and a sheath arranged around the core consists of nine steel filaments. Preferably the two steel filaments constituting the core are either non-twisted filaments or are twisted at a pitch of not less than 30 mm on average, a ratio (ds/dc) of the diameter ds of each steel filament constituting the sheath to the diameter dc of each steel filament constituting the core is within a range of 35-80%, and a ratio (a/b) of the minor diameter a to the major diameter b of the cord cross-section in an arbitrary position in the longitudinal direction of the cord is within a range of 63-100%

2+9 Steel cords for the reinforcement of rubber articles and pneumatic

A two-layered twisted steel cord for reinforcing rubber articles, comprising a core including two filaments and a sheath including six or seven filaments wound around the core, in which an average twist pitch of the core is set to be at least 30 mm, and when six filaments are used for the sheath, a ratio of diameter ds of each filament of the sheath to diameter dc of each filament of the core, �(ds/dc).times.100!, is set in a range of 58.0 %&lt;ds/dc&lt;161.5%. When seven filaments are used for the sheath, the ratio of diameter ds to diameter dc is set in a range of 47.3%&lt;ds/dc&lt;121.1%. The two-layered twisted steel cords are used for reinforcing rubber articles, such as a pneumatic radial tire.

Steel cords for reinforcing rubber articles and pneumatic radial tire

A steel cord for the reinforcement of rubber articles has a three-layer twisting structure comprising a core of 2 steel filaments, a middle sheath layer of 6 steel filaments and an outer sheath layer of 11 steel filaments, in which a ratio of filament diameter ds in the middle and outer sheath layers to filament diameter dc in the core (ds/dc) is within a range of 1.15-1.5 and a twisting pitch of the core is not less than 20 mm, and is used as a reinforcing member in a heavy duty pneumatic radial tire, conveyor belt and the like.

Growing community of inventors

Kodaira, Japan

Takaya Yamanaka