Abstract: Provided is a technique for attaining tire weight reduction while inhibiting occurrence of a product defect caused by deformation by improving the structure of a steel cord used for a carcass ply to improve the resistivity against deformation of a green tire when stored in an unvulcanized state. Also provided is a steel cord for reinforcing rubber articles with a multi-twisted structure in which a plurality of strands 11, 12 formed by twisting a plurality of wires 1, 2, 3 together in a layered-twisted structure are twisted together in a 2-layer-twisted structure. The cord mass is from 35 g/m to 65 g/m, and the ratio of flexural rigidity G (N·mm2) to cord cross section A (mm2), G/A (N) is from 400 N to 650 N.

Abstract: Provided is a technique for attaining tire weight reduction while inhibiting occurrence of a product defect caused by deformation by improving the structure of a steel cord used for a carcass ply to improve the resistivity against deformation of a green tire when stored in an unvulcanized state. Also provided is a steel cord for reinforcing rubber articles with a multi-twisted structure in which a plurality of strands 11, 12 formed by twisting a plurality of wires 1, 2, 3 together in a layered-twisted structure are twisted together in a 2-layer-twisted structure. The cord mass is from 35 g/m to 65 g/m, and the ratio of flexural rigidity G (N·mm2) to cord cross section A (mm2), G/A (N) is from 400 N to 650 N.

Abstract: There is provided a steel cord including a plurality of untwisted core filaments of steel aligned in parallel, and a layer of sheath filaments of steel twisted around the core filaments so as to be unevenly distributed around the core filaments, wherein interstices between the filaments are maintained during vulcanization thereby achieving improved rubber penetration (sufficiently adhering rubber to the core filaments). Since the cross sectional length of the steel cord 10 is greater than the minimum cross sectional length, interstices A are maintained between sheath filaments 14 under the tension and pressure p of the surrounding rubber 16 applied to the steel cord 10 during vulcanization. Rubber 16 penetrates into the steel cord 10 through the interstices A, and sufficiently adhere to core filaments 12 to achieve high rubber penetration.

Abstract: There is provided a steel cord including a plurality of untwisted core filaments of steel aligned in parallel, and a layer of sheath filaments of steel twisted around the core filaments so as to be unevenly distributed around the core filaments, wherein interstices between the filaments are maintained during vulcanization thereby achieving improved rubber penetration (sufficiently adhering rubber to the core filaments). Since the cross sectional length of the steel cord 10 is greater than the minimum cross sectional length, interstices A are maintained between sheath filaments 14 under the tension and pressure p of the surrounding rubber 16 applied to the steel cord 10 during vulcanization. Rubber 16 penetrates into the steel cord 10 through the interstices A, and sufficiently adhere to core filaments 12 to achieve high rubber penetration.

Abstract: A steel cord having a strand construction formed by twisting a plurality of sheath strands each formed by twisting plural filaments around a core strand formed by twisting plural filaments is provided. At least one of the core strand and the sheath strands has a construction of twisting one or more sheath layers each made of plural filaments around a core made of one or plural filaments, and a diameter of a filament constituting an outermost sheath layer is made larger than that of a filament constituting at least one layer located inside thereof, whereby precedent breakage in a part of the filaments is avoided to improve the durability of the steel cord.