A steel cord for rubber reinforcement
AssigneeNV Bekaert SA
InventorAijun ZHANG
Life of this patent
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Abstract
The invention is relating to a steel cord for rubber reinforcement. The steel cord has a construction comprising an outer layer and an inner strand surrounded by and adjacent to the outer layer, the inner strand comprises at least one steel filament with a number of N1 and an average diameter of d1 expressed in mm, the outer layer comprises steel filaments with a number of N2 and an average diameter of d2 expressed in mm, the inner strand has a torque T1 and the outer layer has a torque T2, the relation between T1 and T2 are defined. By doing this, the tip rise problem of the rubber ply reinforced by steel cords is reduced.
Claims15
1-14. (canceled)
A steel cord, said steel cord having a construction comprising an outer layer and an inner strand surrounded by and adjacent to said outer layer, said inner strand comprising at least one steel filament with a number of N1 and an average diameter of d1 expressed in mm, said outer layer comprising steel filaments with a number of N2 and an average diameter of d2 expressed in mm, wherein said inner strand has a torque T1, said outer layer has a torque T2, T1 and T2 satisfy the following formulas:
- T1=G×RT1×π2×D12×d12×N1/16000,
- T2=G×RT2×π2×(D12+D22)×d22×N2/16000,
- |T1+T2|<60,
- wherein,
- D1 is the theoretical diameter of the inner strand while D2 is the theoretical diameter of the steel cord, D1 and D2 are expressed in mm,
- RT1 is the residual torsion of the inner strand while RT2 is the residual torsion of the outer layer expressed in the number of turns per meter in “+” if in clockwise direction or “−” if in anticlockwise direction,
- G is 80000 N/mm2,
- and the absolute value of RT2 is less than 2 turns per meter, and the absolute value of RT1 is no less than 0.05 turns per meter.
Dependencies are inferred from the claim text.