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 cord of a band of a tire has a single-stranded structure in which steel filaments are stranded, and the number of the filaments is not less than three and not greater than six. In a cross-section of the cord, when represents a diameter of a smallest circle that surrounds cross-sections of the filaments, and represents a diameter of each filament, a gap is formed between the filaments such that the diameter is not less than three times the diameter and not greater than six times the diameter in the case of the number of the filaments being three or four. An initial elongation of the cord is not less than 0.1% and not greater than 1.5%.

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).

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 carbon fiber cable includes a core member having multiple thermosetting-resin-impregnated carbon fibers bundled together, and multiple side members each having multiple thermosetting-resin-impregnated synthetic fibers bundled together in each side member. The thermosetting resin is in a cured state and each of the multiple side members has been shaped utilizing curability of the resin. The shaped multiple side members are each in such a state that they are twisted together around the core member.

A steel cord for rubber reinforcement comprises a first group of core filaments (105) having a number of m and a second group of sheath filaments (110) having a number of n, m is three or four, the core filaments (105) are forming a helix, the core filaments (105) are not twisted together and being substantially parallel or the core filaments (105) have a twist pitch being more than 300 mm; the second group and the first group are twisted with each other, and the sheath filaments (110) are forming a flattened helix in the same direction of the helix of the core filaments (105), and the sheath filaments (110) have a cord twist pitch, at any cross-section of the steel cord, at least one interstice between two adjacent core filaments (105) is present. The steel cord has improved abrasion resistance and can contribute to the reduction of the weight of the tire.

Steel cords have a stranded structure in which a plurality of sheath strands is intertwined around the outer circumferential surface of a core strand. The outer circumferential surface of the core strand is covered by a cushioning material made of nonwoven fabric or a resin film.

A multi-strand cord (50) comprises an internal layer (CI) of the cord made up of K=1 two-layer (C1, C3) internal strand (TI), with the internal layer (C1) being made up of Q internal metallic threads (F1), and the external layer (C3) being made up of N external metallic threads (F3), and an external layer (CE) of the cord made up of L>1 two-layer (C1, C3) external strands (TE) wound around the internal layer (CI) of the cord, with the internal layer (C1) being made up of Q internal metallic threads (F1), and the external layer (C3) being made up of N external metallic threads (F3). The cord (50) has an endurance criterion SL40 000 MPa.Math.mm with $SL=\max \left(\frac{{}_{\mathrm{bending\_CI}}}{\mathrm{Cp}};\frac{{}_{\mathrm{bending\_CE}}}{C_r\mathrm{Cp}}\right)$
and a size criterion Ec0.46 with Ec=Sc/Se.

Provided is a steel cord for reinforcing a rubber article in which both the rubber penetrability (rust prevention), and the cord strength and shear resistance are highly achieved. 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. An average value Lc of an amount of clearance between outermost layer sheath filaments constituting an outermost layer sheath of the core strand is from 0.073 to 0.130 mm, and the number of the outermost layer sheath filaments is from 7 to 10.