A two-layer multi-strand cord (60) comprises an internal layer (CI) of the cord made up of J>1 internal strands (TI) and an external layer (CE) of the cord made up of L>1 external strands (TE). The cord satisfies the relationship 95≤MC≤175, where MC=(J×MI+L×ME)/(J+L); MI=200×cos.sup.4(α)×[Q×(D1/2).sup.2×cos.sup.4(β)+P×(D2/2).sup.2×cos.sup.4(δ)+N×(D3/2).sup.2×cos.sup.4(γ)]/[Q×(D1/2).sup.2+P×(D2/2).sup.2+N×(D3/2).sup.2]; and ME=200×cos.sup.4(α′)×[Q′×(D1′/2).sup.2×cos.sup.4(β′)+N′×(D2′/2).sup.2×cos.sup.4(γ′)]/[Q′×(D1′/2).sup.2+N′×(D2′/2).sup.2], where D1, D1′, D2, D2′, and D3 are in mm, α and α′ are the helix angle of each internal and external strand (TI), β and β′ are the helix angle of each internal thread (F1, F1′), δ is the helix angle of each intermediate thread (F2) and γ and γ′ are the helix angle of each external thread (F3, F2′).

A two-layer multi-strand cord (60) comprises an internal layer (CI) of the cord made up of J>1 internal strands (TI) and an external layer (CE) of the cord made up of L>1 external strands (TE). The cord satisfies the relationship 95≤MC≤180, where MC=(J×MI+L×ME)/(J+L); MI=200×cos.sup.4(α)×[Q×(D1/2).sup.2×cos.sup.4(β)+P×(D2/2).sup.2×cos.sup.4(δ)+N×(D3/2).sup.2×cos.sup.4(γ)]/[Q×(D1/2).sup.2+P×(D2/2).sup.2+N×(D3/2).sup.2]; and ME=200×cos.sup.4(α′)×[Q′×(D1′/2).sup.2×cos.sup.4(β′)+P′×(D2′/2).sup.2×cos.sup.4(δ′)+N′×(D3′/2).sup.2×cos.sup.4(γ′)]/[Q′×(D1′/2).sup.2+P′×(D2/2).sup.2+N′×(D3′/2).sup.2], where D1, D1′, D2, D2′, D3 and D3′ are in mm, α and α′ are the helix angle of each internal and external strand (TI), β and β′ are the helix angle of each internal thread (F1, F1′), δ and δ′ are the helix angle of each intermediate thread (F2, F2′) and γ and γ′ are the helix angle of each external thread (F3, F3′).

The invention relates to a multi-strand cord (50) comprising an internal layer (CI) of the cord made up of K=1 three-layer (C1, C2, C3) internal strand (TI), with the internal layer (C1) being made up of Q internal metallic threads (F1), the intermediate layer (C2) being made up of M intermediate metallic threads (F2) 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 three-layer (C1′, C2′, 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′), the intermediate layer (C2′) being made up of M′ intermediate metallic threads (F2′) and the external layer (C3′) being made up of N′ external metallic threads (F3′).

The cord (50) has: an endurance criterion SL≤40 000 MPa.Math.mm with

[00001]$SL=\max \left(\frac{\Delta {\sigma }_{\mathrm{bending}\_\mathrm{CI}}}{\mathrm{Cp}};\frac{\Delta {\sigma }_{\mathrm{bending}\_\mathrm{CE}}}{C_r\times \mathrm{Cp}}\right);$  and a size criterion Ec≥0.46 with Ec=Sc/Se.

Provided is a multi-twisted steel cord for reinforcing a rubber article, the steel cord having cord strength with a small loss as compared to the total strength of filaments constituting the cord and a high rubber penetration. The steel cord includes a plurality of twisted strands in a multi-twisted structure, each strand including a plurality of twisted filaments in two or more layers, in which at least some of the filaments have a tensile strength of 3,000 MPa or more, the steel cord satisfying a filament occupancy of 48% or more and less than 54%, a cord twist angle of 78° or more and less than 84°, an average crossing angle between adjacent filaments other than wrapping filaments of less than 17°, and a gap between adjacent sheath filaments constituting the strand of 0.065 mm or more.

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 SL≤40 000 MPa.Math.mm with

[00001]$SL=\max \left(\frac{\Delta {\sigma }_{\mathrm{bending\_CI}}}{\mathrm{Cp}};\frac{\Delta {\sigma }_{\mathrm{bending\_CE}}}{C_r\times \mathrm{Cp}}\right)$

and a size criterion Ec≥0.46 with Ec=Sc/Se.

The invention relates to a metallic reinforcing cord (10) for tyres for vehicle wheels, comprising from two to ten metallic wires (11) twisted together with a twisting pitch (P) and each having a predetermined diameter. In at least some cross sections of the metallic reinforcing cord (10), at least two of said metallic wires (11) are arranged to a minimum mutual distance greater than, or equal to, 2.5 times the predetermined diameter.

A two-layer multi-strand cord (60) comprises an internal layer (CI) of the cord made up of J>1 internal strands (TI) and an external layer (CE) of the cord made up of L>1 external strands (TE). The cord satisfies the relationship 95≤MC≤175, where MC=(J×MI+L×ME)/(J+L); MI=200×cos.sup.4(α)×[Q×(D1/2).sup.2×cos.sup.4(β)+N×(D2/2).sup.2×cos.sup.4(γ)]/[Q×(D1/2).sup.2+N×(D2/2).sup.2]; and ME=200×cos.sup.4(α′)×[Q′×(D1′/2).sup.2×cos.sup.4(β′)+P′×(D2′/2).sup.2×cos.sup.4(δ′)+N′×(D3′/2).sup.2×cos.sup.4(β′)]/[Q′×(D1′/2).sup.2+P′×(D2/2).sup.2+N′×(D3′/2).sup.2], where D1, D1′, D2, D2′, and D3′ are in mm, α and α′ are the helix angle of each internal and external strand (TI), β and β′ are the helix angle of each internal thread (F1, F1′), δ′ is the helix angle of each intermediate thread (F2′) and γ and γ′ are the helix angle of each external thread (F2, F3′).

A two-layer multi-strand cord (60) comprises an internal layer (CI) of the cord made up of J>1 internal strands (TI) and an external layer (CE) of the cord made up of L>1 external strands (TE). The cord satisfies the relationship 100≤MC≤175, where MC=(J×MI+L×ME)/(J+L); MI=200×cos.sup.4(α)×[Q×(D1/2).sup.2×cos.sup.4(β)+N×(D2/2).sup.2×cos.sup.4(γ)]/[Q×(D1/2).sup.2+N×(D2/2).sup.2]; and ME=200×cos.sup.4(α′)×[Q′×(D1′/2).sup.2×cos.sup.4(β′)+N′×(D2′/2).sup.2×cos.sup.4(γ′)]/[Q′×(D1′/2).sup.2+N′×(D2′/2).sup.2], where D1, D1′, D2, D2′ are in mm, α and α′ are the helix angle of each internal and external strand (TI), β and β′ are the helix angle of each internal thread (F1, F1′), and γ and γ′ are the helix angle of each external thread (F2, F2′).

A method for manufacturing a rope structure comprising providing, around a first roller and a second roller, a loop including a plurality of twisted strands. The method further comprising feeding a plurality of body strands onto the loop, feeding including, with the plurality of body strands connected to the loop, moving the loop about the first roller and the second roller to cause the body strands to lay and be twisted on the plurality of twisted strands.

The invention provides a steel cord with a construction of n×1, n is the number of the steel filaments of the steel cord, the steel cord has an elongation at 2.5N-50N of less than 1.2% and a twist pitch of greater than 16 mm, each of the steel filaments has a form of helical wave with a wave length L expressed in mm and a wave height H expressed in mm when being unravelled from said steel cord, L is greater than 16 mm, each of the steel filaments has a space volume Vs satisfying that, Vs=L×H.sup.2×π/4, and Vs>20 mm.sup.3. The invention steel cord is beneficial for the stress distribution.