Abstract: A steel cord for rubber reinforcement comprises a first group of core filaments (105) having a number of m and a second group of sheath filaments (110) having a number of n, m is three or four, the core filaments (105) are forming a helix, the core filaments (105) are not twisted together and being substantially parallel or the core filaments (105) have a twist pitch being more than 300 mm; the second group and the first group are twisted with each other, and the sheath filaments (110) are forming a flattened helix in the same direction of the helix of the core filaments (105), and the sheath filaments (110) have a cord twist pitch, at any cross-section of the steel cord, at least one interstice between two adjacent core filaments (105) is present. The steel cord has improved abrasion resistance and can contribute to the reduction of the weight of the tire.

Abstract: A steel cord for rubber reinforcement comprises a first group of core filaments (105) having a number of m and a second group of sheath filaments (110) having a number of n, m is three or four, the core filaments (105) are forming a helix, the core filaments (105) are not twisted together and being substantially parallel or the core filaments (105) have a twist pitch being more than 300 mm; the second group and the first group are twisted with each other, and the sheath filaments (110) are forming a flattened helix in the same direction of the helix of the core filaments (105), and the sheath filaments (110) have a cord twist pitch, at any cross-section of the steel cord, at least one interstice between two adjacent core filaments (105) is present. The steel cord has improved abrasion resistance and can contribute to the reduction of the weight of the tire.

Abstract: A steel cord having a plurality of strands twisted together with a cord twist pitch. Each strand having a plurality of filaments twisted together with a strand twist pitch. The elongation at break of the steel cord is no less than 5%. The strand having a strand twist angle. The steel cord having a cord twist angle. When the sum of the strand twist angle and the cord twist angle is between 20 and 29 degree, the structural elongation of the steel cord is no less than 2.0%. When the sum of the strand twist angle and the cord twist angle is between 30 and 38 degree, the structural elongation of the steel cord is no less than 2.5%. When the sum of the strand twist angle and the cord twist angle is between 39 and 48 degree, the structural elongation of the steel cord is no less than 3.0%.

Abstract: A steel cord used for reinforcing rubber product with an oval cross-section has a structure of m+n, while m is the number of core wires (26) and n is the number of the outer layer wires (22). The core wire (26) is untwisted while m is 1 or the core wires (26) are untwisted and aligned in parallel while m is between 2 and 4, and the outer layer wires (22) are twisted around said core wires (26). The core wires (26) are oval wires and the outer layer wires (22) are round wires. The wires (22, 26) in the steel cord have a carbon content not less than 0.60%.

Abstract: A steel cord used for reinforcing rubber product with an oval cross-section has a structure of m+n, while m is the number of core wires (26) and n is the number of the outer layer wires (22). The core wire (26) is untwisted while m is 1 or the core wires (26) are untwisted and aligned in parallel while m is between 2 and 4, and the outer layer wires (22) are twisted around said core wires (26). The core wires (26) are oval wires and the outer layer wires (22) are round wires. The wires (22, 26) in the steel cord have a carbon content not less than 0.60%.