Abstract:
PROBLEM TO BE SOLVED: To provide a steel cord for reinforcing rubber, which reduces the cord diameter and suppressing a dimensional change while ensuring adhesiveness between the cord and the rubber and to provide a pneumatic radial tire using the steel cord. SOLUTION: The steel cord 10 used in a belt layer 6 is obtained by twisting 5 side wires 12 having the same wire diameter as a core wire 11 together on the outside of the one core wire 11 subjected to helical preforming and arranging the wires. The steel cord has a flat structure in which the circumscribed circle C11 of the core wire 11 and the circumscribed circle C12 of the side wires 12 form an elliptical shape, respectively. The torsional direction of the core wire 11 is the same as the twisting direction of the side wires 12 and the preforming pitch of the core wire 11 is the same as the twisting pitch of the side wires 12. The minor axis ds of the circumscribed circle C11 of the core wire 11 is ds>d to the wire diameter d. The minor diameter Ds of the circumscribed circle C12 of the side wires 12 is Ds 3.6d. The ratio of the minor diameter Ds to the major diameter D1 is D1/Ds>1.2. COPYRIGHT: (C)2008,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a steel cord having high strength usable even for a heavy-load tire, good rubber penetrability into the interior of the steel cord, low rigidity in the rotative direction of the tire and high rigidity in the direction intersecting the rotative direction of the tire at right angles. SOLUTION: The steel cord 1 has a 3×3 structure prepared by laying 3 strands 2 obtained by laying 3 wires 3 without a core strand. The external tangent line S2 of the strands 2 is a nearly elliptical shape in nearly the same direction in the longitudinal direction and the external tangent line S1 of the steel cord 1 is a nearly elliptical shape in nearly the same direction as the elliptical direction of the strands 2. The flatness (b2/a2) of the strands 2 is 1.15-2.70 and the flatness (b1/a1) of the steel cord 1 is 1.15-2.70. Furthermore, the adjacent strands repeat contact or approach and separation at least twice in one lay pitch and the maximum gap when separated is present near the extreme points of the major axis. The gap interval H1 is ≥3/100 mm. COPYRIGHT: (C)2007,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a steel cord obtained by stranding one layer of a sheath filament consisting of steel while unevenly distributing, around a plurality of core filaments as non-stranded state, doubled in parallel and improving the rubber penetrating property so as to secure the gaps among the filaments on vulcanization (so as to attach the rubber on the core filaments sufficiently). SOLUTION: Since the cross sectional longer diameter of the steel cord 10 is set as larger than the minimum cross sectional longer diameter, on covering the steel cord with rubber 16 for vulcanizing, the gap A among the sheath filaments 14 is secured even on affecting a tensional force and a pressure p from the surrounding rubber against the steel cord, and the rubber 16 can penetrate through the gaps, and the core filaments 12 are sufficiently attached with the rubber 16 and exhibit a high rubber penetration. COPYRIGHT: (C)2006,JPO&NCIPI
Abstract:
PROBLEM TO BE SOLVED: To suppress the longitudinal elongation of an elliptic open cord caused by the pulling force under a low load range and keep good rubber penetration. SOLUTION: The strands of a steel cord 10 having a 1×3 (1×4, 1×5 or 1×6) elliptic open structure and a strand diameter of 0.20-0.45 mm are nonuniformly arranged. The angle α between the tangential line S of the outer circumference of the strands at the contacting point of two strands 1, 2 circumscribed with each other near the minor diameter part of one side of a prescribed cord cross-section and the line T connecting the centers of strands 3 positioned closest to the tangential line S near the minor diameter part at the other side on the cord cross-section is set to 3-25°. The decrease of the gap at the major diameter side is suppressed by the drag force caused by the contact at the minor diameter side by the application of a low tension. The penetration of rubber is maintained at a high level by the structure to improve the fatigue resistance. COPYRIGHT: (C)2006,JPO&NCIPI
Abstract:
PROBLEM TO BE SOLVED: To provide a pneumatic radial tire having a belt capable of reducing weight of the tire while maintaining durability of the tire. SOLUTION: Steel cords constituting belt layers 14, 15, 16 of the pneumatic radial tire 10 are cords constituted in such a way that three core filaments are arranged in parallel without twisting them, a plurality of sheath filaments are intertwined around them, and cord outer profile shape of a vertical face in the longitudinal direction of the cord is like track. The outer profile shape of the cord is arranged in the longitudinal direction without twisting, and long axis of the cord is arranged in the same direction for the direction of belt width and in parallel with the direction of belt width at distance of 0.6 mm or more. COPYRIGHT: (C)2004,JPO
Abstract:
PROBLEM TO BE SOLVED: To provide a run-flat tire for winter of a side reinforcing type with excellent steering performance at the time of a run-flat traveling on an iced road surface, in particular, by suppressing a buckling phenomenon apt to occur at the time of a tire blow-out. SOLUTION: This tire is provided with carcass 25 made of at least a sheet of ply having cords extended in toroidal shapes and substantially radially arrayed between bead cores 23 buried in each of a pair of bead parts 22 and a belt 32 made of at least a cord layer in which a plurality of steel cords are covered with rubber on an outer peripheral side of a crown part 26 of the carcass 25. The cord layers composing the belt 32 are made reinforcing cord layers 31a and 31b to be flat cords in which the steel cords have sectional shapes of substantially elliptical shapes and the major axes are arranged in directions in which the axes have inclined angles in a cross section width direction 33 of the belt 32.