A multi-strand cord (50) comprises an internal layer (CI) made up of K=1 internal strand (TI) having two layers (C1, C3), 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) made up of L>1 external strands (TE) having two layers (C1, C3) wound around the internal layer (CI), 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 energy-to-break per unit area ES145 N.Math.mm.sup.1 with $ES={.Math.}_{i=1}^{Nc}{F}_{mi}{.Math.}_{i=1}^{Nc}{A}_{ti}/\mathrm{Nc}\mathrm{Cfrag}/D$
where ${.Math.}_{i=1}^{Nc}{F}_{mi}$
is the sum of the forces at break, ${.Math.}_{i=1}^{Nc}{A}_{ti}$
is the sum of the total elongation, Cfrag is the coefficient of weakening, and D is the diameter.

A multi-strand cord (50) comprises an internal layer (CI) made up of K=1 internal strand (TI) having two layers (C1, C3), 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) made up of L>1 external strands (TE) having two layers (C1, C3) wound around the internal layer (CI), 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 energy-to-break per unit area ES145 N.Math.mm.sup.1 with $ES={.Math.}_{i=1}^{Nc}{F}_{mi}{.Math.}_{i=1}^{Nc}{A}_{ti}/\mathrm{Nc}\mathrm{Cfrag}/D$
where ${.Math.}_{i=1}^{Nc}{F}_{mi}$
is the sum of the forces at break, ${.Math.}_{i=1}^{Nc}{A}_{ti}$
is the sum of the total elongation, Cfrag is the coefficient of weakening, and D is the diameter.

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.

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 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 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.

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.

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. 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.