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 compact steel cord is provided. The cord includes a core-filament I steel wire with a diameter of d0, and four middle-layer M steel wires with a diameter of d1 and eight outer-layer O steel wires with a diameter of d2 that are twisted around the core-filament I steel wire in the same lay direction and the same lay length. Gaps L are reserved between the outer-layer O steel wires, an average width of the gaps L is not smaller than 0.02 mm, and the total size of the gaps L is larger than d0 and smaller than d1. The steel cord of a stable structure can be obtained by controlling the proportion of the sizes of all layers of monofilaments, the rubber coating performance of a tire cord can also be improved, the corrosion resistance, fatigue resistance, impact resistance and adhesion retention of a tire are improved.

A compact steel cord is provided. The cord includes a core-filament I steel wire with a diameter of d0, and four middle-layer M steel wires with a diameter of d1 and eight outer-layer O steel wires with a diameter of d2 that are twisted around the core-filament I steel wire in the same lay direction and the same lay length. Gaps L are reserved between the outer-layer O steel wires, an average width of the gaps L is not smaller than 0.02 mm, and the total size of the gaps L is larger than d0 and smaller than d1. The steel cord of a stable structure can be obtained by controlling the proportion of the sizes of all layers of monofilaments, the rubber coating performance of a tire cord can also be improved, the corrosion resistance, fatigue resistance, impact resistance and adhesion retention of a tire are improved.

A commercial vehicle tire of a radial type of construction with a cross-sectional height of 135 mm to 200 mm, a load index of 121 to 154, a radial-ply casing with at least one casing ply composed of steel cords embedded in rubber and with bead regions with bead cores and bead fillers around which the casing ply runs so as to form turn-ups. The casing ply is reinforced with steel cords of the construction 1+6, wherein the core filament (1) has a diameter (d.sub.1) of 0.19 mm to 0.22 mm and the ply filaments (2) have coinciding diameters (d.sub.2) of 0.17 mm to 0.20 mm, wherein the diameter (d.sub.2) of the ply filaments (2) is less than the diameter (d.sub.1) of the core filament (1) by at least 0.01 mm and wherein, at the crown of the tire, the steel cords are arranged in the casing ply with 60 epdm to 75 epdm.

A commercial vehicle tire of a radial type of construction with a cross-sectional height of 135 mm to 200 mm, a load index of 121 to 154, a radial-ply casing with at least one casing ply composed of steel cords embedded in rubber and with bead regions with bead cores and bead fillers around which the casing ply runs so as to form turn-ups. The casing ply is reinforced with steel cords of the construction 1+6, wherein the core filament (1) has a diameter (d.sub.1) of 0.19 mm to 0.22 mm and the ply filaments (2) have coinciding diameters (d.sub.2) of 0.17 mm to 0.20 mm, wherein the diameter (d.sub.2) of the ply filaments (2) is less than the diameter (d.sub.1) of the core filament (1) by at least 0.01 mm and wherein, at the crown of the tire, the steel cords are arranged in the casing ply with 60 epdm to 75 epdm.

This steel cord for reinforcing a rubber article includes one core strand having a two-layer twisted layer structure formed by intertwining a plurality of steel filaments, and a plurality of sheath strands having a twisted layer structure formed by intertwining a plurality of steel filaments. The sheath strands are intertwined around the core strand, a core of the core strand is formed by two core filaments, and the diameter of outermost layer sheath filaments forming an outermost layer sheath of each sheath strand is greater than the diameter of filaments inside the outermost layer sheath of the sheath strand.

This steel cord for reinforcing a rubber article includes one core strand having a two-layer twisted layer structure formed by intertwining a plurality of steel filaments, and a plurality of sheath strands having a twisted layer structure formed by intertwining a plurality of steel filaments. The sheath strands are intertwined around the core strand, a core of the core strand is formed by two core filaments, and the diameter of outermost layer sheath filaments forming an outermost layer sheath of each sheath strand is greater than the diameter of filaments inside the outermost layer sheath of the sheath strand.

The present disclosure relates to a cable bead for a pneumatic tire which constitutes a bead part of a pneumatic tire, improves rubber permeability by restricting a ratio between a diameter of a cable and a pitch of an outer wire, and improves durability of a pneumatic tire by improving rubber adhesive properties through cobalt coating on a surface of the outer wire, and a pneumatic tire having the same, and the cable bead for a pneumatic tire is characterized in that the diameter D of the cable and a pitch P of the outer wire 20 satisfy a relationship formula, P/D=25 to 45, and further characterized in that the surface of the outer wire 20 is coated with cobalt after wire drawing.