Provided is a rubber article-reinforcing steel cord having improved shear fatigue resistance while reducing the weight of the steel cord by using a wire of high tensile strength. The rubber article-reinforcing steel cord 10 is a steel cord 10 having a two-layer twisted structure comprising a core filament 11 composed of a plurality of filaments and a sheath filament 12 composed of a plurality of filaments twisted around the core filament 11, wherein the tensile strength of the core filament 11 is higher than the tensile strength of the sheath filament 12, and the core filament 11 and the sheath filament 12 are twisted together in the same direction and the same pitch.

The invention relates to a pneumatic utility vehicle tire of a radial type of construction, in particular for trucks, buses, and truck trailers, which has a four-ply or multi-ply belt (4) comprising a barrier ply (5), two working plies (6, 8) and a 0° ply (7), wherein steel cords (10) are arranged in the 0° ply (7), comprising at least two strands (11) each with at least 6 steel filaments (12), and wherein twisting causes each strand to have an identical first twist angle α and the steel cord to have a second twist angle β.

The invention is distinguished in that the steel cord (10) of the 0° ply (7) has the construction 2 to 4×n×d, with n=6 to 8 and with d=0.15 mm to 0.29 mm, wherein this construction means that the steel cord (10) has 2 to 4 twisted-together strands (11), wherein each strand (10) contains 6 to 8 steel filaments (12), in that each steel filament (12) of the steel cord (10) has the same filament diameter (13) and in that the sum of the twist angle α of a strand (11) and the twist angle β of the steel cord lies between 37° and 50°, preferably between 37° and 45°, particularly preferably between 38.5° and 42.5° and most particularly preferably between 39.3° and 41.3°.

The invention relates to a process for manufacturing a metallic reinforcing cord (10) for tyres for vehicle wheels. The process comprises providing at least one elongated element (15) comprising at least one metallic wire (11) twisted together with at least one textile yarn (20) and removing said at least one textile yarn (20) from said at least one elongated element (15) to form the aforementioned metallic reinforcing cord (10). Such a metallic reinforcing cord (10) has a helical geometry, consisting only of said at least one metallic wire (11) that extends along a helical path. The invention also relates to an apparatus (1) for manufacturing the aforementioned metallic reinforcing cord (10).

Provided are: a tire steel cord having not only excellent cutting resistance and corrosion resistance but also excellent processability in plant; and a pneumatic tire including the same. The tire steel cord has a layer-twisted structure including: a core 11 composed of two core filaments 1; and a sheath 12 composed of eight sheath filaments 2 that are twisted together around the core 11, in which tire steel cord the two core filaments 1 constituting the core 11 are twisted together, the twisting direction of the core filaments 1 and that of the sheath filaments 2 are different, and a diameter (Dc) of the core filaments 1 and a diameter (Ds) of the sheath filaments 2 satisfy a relationship represented by the following Equation (1):
0.90≤Ds/Dc≤1.10  (1).

The invention relates to a metallic reinforcing cord (10) for tyres for vehicle wheels, comprising: —a) a plurality of metallic wires (11) twisted to one another with a single twisting pitch (P), or—b) a single metallic wire twisted with at least one second metallic wire with a single twisting pitch, or—c) a plurality of first metallic wires twisted to one another with a first twisting pitch to define a first strand of metallic wires and at least one second metallic wire twisted with said first strand of metallic wires with a second twisting pitch equal to or different from the first twisting pitch. The metallic reinforcing cord (10) has a part load elongation greater than or equal to 1%.

A cord for reinforcing elastomers excellent in adhesion to elastomers such as rubber is provided. The cord is a cord for reinforcing elastomers (10) that includes metallic filaments (1) and a resin filament (2) twisted together, the resin filament (2) being made from a polymeric material having a melting point or softening point of 80 to 160° C. The cord for reinforcing elastomers includes a core and at least one sheath layer, wherein, after vulcanization, a distance w between metallic filaments (1b) forming an outermost sheath layer is 100 μm or less, and, on a cross section of the cord taken along a direction orthogonal to an axial direction, a filling ratio, which is a ratio of an area of a polymeric material (3) derived from the resin filament (2) to a gap region is 52 to 120%, where the gap region is defined as a portion occupied by a material other than the metallic filaments (1) within a region formed by connecting the centers of the individual metallic filaments (1b) constituting the outermost sheath layer.

A pneumatic radial tire includes belt layers disposed on an outer circumferential side of a carcass layer in a tread portion. The belt layers are formed of steel cords in a N+M structure in which the number of wire strands N of an inner layer is 2 to 4 and the number of wire strands M of an outer layer is 2 to 7. A twist direction of the inner layer is different from a twist direction of the outer layer. The steel cords are inclined with respect to a tire circumferential direction to intersect each other in layers of the belt layers. A belt cover layer disposed on an outer circumferential side of the belt layers is formed of organic fiber cords having elongation of 2.0% to 4.0% under 2.0 cN/dtex load. The organic fiber cords are wound spirally along the tire circumferential direction.

Provided is an elastomer reinforcement cord with improved rust inhibition. An elastomer reinforcement cord (10) includes metal filaments and a polymer material. The elastomer reinforcement cord (10) has a multi-strand structure which includes: at least one core strand (21) formed by twisting plural metal filaments (1a) and (1b) together; and two or more sheath strands (22) each formed by twisting plural metal filaments (11a) and (11b) together, and in which the sheath strands are twisted together around the core strand. In a region surrounded by a line connecting the centers of the metal filaments constituting the outermost sheath layer of the core strand at a cross-section in a direction orthogonal to an axial direction after vulcanization of the core strand, when a region occupied by other than the metal filaments is defined as a gap region, a filling rate, which is a ratio of the area of the polymer material with respect to the gap region, is 52% to 120%.

Provided is an elastomer reinforcement cord in which the problem of stress concentration at an interface between an elastomer and a metal cord is solved and the durability is thereby improved. The elastomer reinforcement cord includes metal filaments (1a) and (1b), and a polymer material (3) having a melting point or softening point of 80° C. to 160° C. The elastomer reinforcement cord has a core (11) and at least one sheath layer (12). In a region surrounded by a line connecting the centers of the metal filaments constituting the outermost sheath layer at a cross-section in a direction orthogonal to an axial direction after vulcanization, when a region occupied by other than the metal filaments is defined as a gap region, the polymer material is contained in this gap region, and a filling rate, which is a ratio of the area of the polymer material, is higher than 120%, taking the area of the gap region as 100%.

Provided is an elastomer reinforcement cord with improved rust resistance. An elastomer reinforcement cord 10 includes metal filaments and a polymer material. The elastomer reinforcement cord 10 has a multi-strand structure which includes: at least one core strand 21 formed by twisting plural metal filaments 1a and 1b together; and two or more sheath strands 22 each formed by twisting plural metal filaments 11a and 11b together, the sheath strands being twisted together around the core strand. An intra-sheath-strand filling rate a, which is a ratio of the area of the polymer material with respect to an intra-sheath-strand gap region A, is 52% or higher, and an inter-strand filling rate b, which is a ratio of the area of the polymer material with respect to an inter-strand gap region B, is 75% or higher.