Provided is a steel cord for reinforcing rubber articles, which can prevent a reduction in the strength of the steel cord caused by twisting steel filaments, and a tire and a crawler using the steel cord. Provided is a steel cord 1 for reinforcing rubber articles formed by twisting a plurality of sheath strands 3 are twisted around a core strand 2, and the core strand 2 comprises: a core composed of two core filaments 2a aligned in parallel without being twisted; and at least one sheath composed of a plurality of sheath filaments 2b twisted around the core, and a diameter dc of the core filament 2a and a diameter ds of the sheath filament 2b satisfy the following expression (1):

dc<ds (1)

and the tensile strength T (MPa) of the core filament 2a satisfies the relationship represented by the following expression (2):

T<365017000(dc0.15).sup.2 (2).

A composite wire has a thermoplastic core component and a sheath. The sheath includes at least two groups of reinforcement threads wrapped around the core component. The at least two groups of reinforcement threads form angles with the core component, with the overall sum of all angles which are essentially zero.

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 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).

The present invention relates to an engineered fiber bundle for reinforcement of composite materials. Specifically, the engineered fiber bundles of the present invention enhance the tensile behavior of the composites reinforced with the fiber bundles. Methods of making the same are further provided.

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.