A cord reinforces a rubber article. The cord includes a core strand having a two-layer twisted layer structure formed by intertwining a plurality of filaments, a plurality sheath strands intertwined around the core strand, the sheath strands having a twisted layer structure formed by intertwining a plurality of filaments, and a wrap wire applied around the core strand and at least one of the sheath strands. The wrap wire creating a permanent and stable minimum gap between the core strand and the sheath strands.

A cord reinforces a rubber article. The cord includes a core strand having a two-layer twisted layer structure formed by intertwining a plurality of filaments, a plurality sheath strands intertwined around the core strand, the sheath strands having a twisted layer structure formed by intertwining a plurality of filaments, and a wrap wire applied around the core strand and at least one of the sheath strands. The wrap wire creating a permanent and stable minimum gap between the core strand and the sheath strands.

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 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 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 steel cord for the reinforcement of elastomer products such as elevator belts, conveyor belts, synchronous or timing belts or hoses or tyres is presented. The steel cord comprises strands and monofilaments made of steel filaments. The strands themselves are also made of steel filaments twisted together. The strands form the outer layer of the steel cord. The monofilaments are twisted into the cord with the same lay length and direction as the strands and are positioned in the valleys between the strands on the radial outer side of the steel cord. The steel cord has the advantage that it has a better fill factor and a rounder aspect. Furthermore the monofilaments may act as an early wear indicator of the elastomer product.

The invention provides a steel cord for rubber reinforcement. The steel cord comprises a core strand and at least three outer strands twisted around the core strand, the core strand comprises at least one first core filament and multiple first outer filaments twisted around the first core filament, each outer strand comprises a number of second filaments, at least one of multiple first outer filaments is preformed prior to being twisted into the core strand, and at least one of second steel filaments is straight prior to being twisted to form each outer strand. The steel cord has improved performance on core filament migration.

The invention provides a steel cord for rubber reinforcement. The steel cord comprises a core strand and at least three outer strands twisted around the core strand, the core strand comprises at least one first core filament and multiple first outer filaments twisted around the first core filament, each outer strand comprises a number of second filaments, at least one of multiple first outer filaments is preformed prior to being twisted into the core strand, and at least one of second steel filaments is straight prior to being twisted to form each outer strand. The steel cord has improved performance on core filament migration.

Provided is a steel cord for rubber article reinforcement which has excellent corrosion resistance and productivity without deterioration of adhesion with rubber. A steel cord (1) for rubber article reinforcement, in which plural steel filaments (2) are twisted together, includes: a core having at least one core filament (2c); and a sheath having at least one sheath layer formed by twisting at least one sheath filament (2s) around the core. In this steel cord (1), brass plating is performed on the steel filaments (2) and zinc plating is further performed on the outer circumference of the brass plating of the core filament (2c), and the steel filaments (2) have a diameter d of 0.1 mm to 0.6 mm.