Provided is a steel cord for reinforcing a rubber article which can further improve cut resistance when applied to a tire. Provided is a steel cord for reinforcing a rubber article including: one core strand 11 having a layered-twisted structure formed by twisting a plurality of steel filaments 1; and a plurality of sheath strands 12 having a layered-twisted structure formed by twisting a plurality of steel filaments 2, wherein the sheath strands are twisted around the core strand. A ratio S1/S of the sum S1 of cross-sectional areas of outermost layer sheath filaments constituting an outermost layer sheath of the core strand to the sum S of cross-sectional areas of all filaments constituting the core strand is from 0.69 to 0.74, and a ratio Ps/P of the sum Ps of strengths of the sheath strands to strength P of the cord as a whole is from 0.81 to 0.85.

Provided is a steel cord for reinforcing a rubber article which can further improve cut resistance when applied to a tire while maintaining the amount of steel to be used. A steel cord for reinforcing a rubber article comprising: one core strand 11 having a two-layered layered-twisted structure formed by twisting a plurality of steel filaments 1; and a plurality of sheath strands 12 having a layered-twisted structure formed by twisting a plurality of steel filaments 2, wherein the sheath strands are twisted around the core strand. A ratio dc/ds of a diameter dc of a sheath filament constituting the sheath of the core strand to a diameter ds of an outermost layer sheath filament constituting the outermost layer sheath of the sheath strand is more than 1.25 and not more than 1.50.

Provided is a steel cord for reinforcing a rubber article which can further improve cut resistance when applied to a tire while maintaining the amount of steel to be used. A steel cord for reinforcing a rubber article comprising: one core strand 11 having a two-layered layered-twisted structure formed by twisting a plurality of steel filaments 1; and a plurality of sheath strands 12 having a layered-twisted structure formed by twisting a plurality of steel filaments 2, wherein the sheath strands are twisted around the core strand. A ratio dc/ds of a diameter dc of a sheath filament constituting the sheath of the core strand to a diameter ds of an outermost layer sheath filament constituting the outermost layer sheath of the sheath strand is more than 1.25 and not more than 1.50.

Provided are: a tire steel cord having not only excellent cutting resistance and corrosion resistance but also excellent processability in plant; and a pneumatic tire including the same. The tire steel cord has a layer-twisted structure including: a core 11 composed of two core filaments 1; and a sheath 12 composed of eight sheath filaments 2 that are twisted together around the core 11, in which tire steel cord the two core filaments 1 constituting the core 11 are twisted together, the twisting direction of the core filaments 1 and that of the sheath filaments 2 are different, and a diameter (Dc) of the core filaments 1 and a diameter (Ds) of the sheath filaments 2 satisfy a relationship represented by the following Equation (1):

0.90Ds/Dc1.10(1).

Provided are: a tire steel cord having not only excellent cutting resistance and corrosion resistance but also excellent processability in plant; and a pneumatic tire including the same. The tire steel cord has a layer-twisted structure including: a core 11 composed of two core filaments 1; and a sheath 12 composed of eight sheath filaments 2 that are twisted together around the core 11, in which tire steel cord the two core filaments 1 constituting the core 11 are twisted together, the twisting direction of the core filaments 1 and that of the sheath filaments 2 are different, and a diameter (Dc) of the core filaments 1 and a diameter (Ds) of the sheath filaments 2 satisfy a relationship represented by the following Equation (1):

0.90Ds/Dc1.10(1).

Provided is a pneumatic tire in which the crack propagation resistance of crossing belt layers is improved without deterioration of the cutting resistance and the irregular wear resistance. The pneumatic tire includes a belt composed of at least three belt layers 103 on the tire radial-direction outer side of a carcass 102, the at least three belt layers 103 including two crossing belt layers that are inclined in the opposite directions across the tire equatorial plane. In this pneumatic tire, a reinforcing material of crossing belt layers 103a and 103b is a steel cord which has a layer-twisted structure including a core composed of two core filaments and a sheath composed of eight sheath filaments that are twisted together around the core, and a steel cord amount in the crossing belt layers 103a and 103b, which is represented by the following Equation (1), is 23 to 49: Steel cord diameter (mm)Steel cord end count (steel cords/50 mm) (1).

Provided is a pneumatic tire in which the crack propagation resistance of crossing belt layers is improved without deterioration of the cutting resistance and the irregular wear resistance. The pneumatic tire includes a belt composed of at least three belt layers 103 on the tire radial-direction outer side of a carcass 102, the at least three belt layers 103 including two crossing belt layers that are inclined in the opposite directions across the tire equatorial plane. In this pneumatic tire, a reinforcing material of crossing belt layers 103a and 103b is a steel cord which has a layer-twisted structure including a core composed of two core filaments and a sheath composed of eight sheath filaments that are twisted together around the core, and a steel cord amount in the crossing belt layers 103a and 103b, which is represented by the following Equation (1), is 23 to 49: Steel cord diameter (mm)Steel cord end count (steel cords/50 mm) (1).

A steel cord has a stranded structure comprising a plurality of sheath strands intertwined around the outer circumferential surface of a core strand; and a filament having a linear mass density of at least 560 dtex and not more than 2,200 dtex wrapped in a spiral around the outer circumferential surface of the core strand. The steel cord is embedded in an unvulcanized rubber member to mold a molded rubber article, which is then vulcanized.

A steel cord has a stranded structure comprising a plurality of sheath strands intertwined around the outer circumferential surface of a core strand; and a filament having a linear mass density of at least 560 dtex and not more than 2,200 dtex wrapped in a spiral around the outer circumferential surface of the core strand. The steel cord is embedded in an unvulcanized rubber member to mold a molded rubber article, which is then vulcanized.

A device for producing a strand or a cable, in particular a wire strand or wire cable, which device includes a rotatable arrangement for feeding cords to a twisting point, at which the cords are to be twisted with one another, and an installation for heating at least one of the cords. The heating installation is rotatable jointly with the feed arrangement. The heating installation is designed to heat a cord provided for forming a center strand or a cable core and/or cords for forming outer strands, and preferably has burner for fuel and/or an electrically operated heater.