In a tire 2, on a cross-section, three or more rows in each of which cross-sections 30 of a wire are aligned almost in the axial direction, are layered in the radial direction. The cross-sections 30 of the wire in a first row disposed on an innermost side in the radial direction and the cross-sections 30 of the wire in a second row layered outward of the first row are staggered. On a cross-section obtained by the tire 2 being cut at a plane perpendicular to the circumferential direction, an outline of a heel surface 36 of a bead 8 portion has an arc C that projects toward an outside of the bead 8 portion. A radius R of curvature of the arc C is greater than or equal to 8 mm and not greater than 12 mm.

In a tire 2, on a cross-section, three or more rows in each of which cross-sections 30 of a wire are aligned almost in the axial direction, are layered in the radial direction. The cross-sections 30 of the wire in a first row disposed on an innermost side in the radial direction and the cross-sections 30 of the wire in a second row layered outward of the first row are staggered. On a cross-section obtained by the tire 2 being cut at a plane perpendicular to the circumferential direction, an outline of a heel surface 36 of a bead 8 portion has an arc C that projects toward an outside of the bead 8 portion. A radius R of curvature of the arc C is greater than or equal to 8 mm and not greater than 12 mm.

The present invention has an object of providing a pneumatic tire that exhibits better uniformity by improving the wire wound body for constituting the bead core. The pneumatic tire 1 comprises a bead core 5 comprising a wire wound body 10 in which one bead wire 10a is spirally wound in a continuous around a tire rotational axis CL so that a plurality of layers of the bead wire are formed in a radial direction of the tire. The wire wound body 10 comprises a first part 13 and a second part 14. The first part 13 comprises a plurality of layers of the bead wire 10a each circumferentially extending with a constant radius from the tire rotational axis CL. The second part comprises a plurality of layers of the bead wire 10a each circumferentially extending while changing its radius from the tire rotational axis CL.

The present invention has an object of providing a pneumatic tire that exhibits better uniformity by improving the wire wound body for constituting the bead core. The pneumatic tire 1 comprises a bead core 5 comprising a wire wound body 10 in which one bead wire 10a is spirally wound in a continuous around a tire rotational axis CL so that a plurality of layers of the bead wire are formed in a radial direction of the tire. The wire wound body 10 comprises a first part 13 and a second part 14. The first part 13 comprises a plurality of layers of the bead wire 10a each circumferentially extending with a constant radius from the tire rotational axis CL. The second part comprises a plurality of layers of the bead wire 10a each circumferentially extending while changing its radius from the tire rotational axis CL.

In a pneumatic tire (1) that achieves both ride comfort and steering stability at a high level, a bead core (5) has a ratio of the maximum width of the core to the height of the core of 0.8 or less in a cross-section in the tire width direction. A cord (9) is provided in at least one part from a bead portion (2) to a sidewall portion (3) at an angle of 0 to 10° with respect to the circumferential direction. The cord (9) has an inflection point in a stress-strain curve, with a low elastic modulus in a low-strain region at or below the inflection point, and a high elastic modulus in a high-strain region above the inflection point.

In a pneumatic tire (1) that achieves both ride comfort and steering stability at a high level, a bead core (5) has a ratio of the maximum width of the core to the height of the core of 0.8 or less in a cross-section in the tire width direction. A cord (9) is provided in at least one part from a bead portion (2) to a sidewall portion (3) at an angle of 0 to 10° with respect to the circumferential direction. The cord (9) has an inflection point in a stress-strain curve, with a low elastic modulus in a low-strain region at or below the inflection point, and a high elastic modulus in a high-strain region above the inflection point.

Provided is a pneumatic tire having laminated reinforcement layers with organic fiber over a polygonal cross-section bead core, and in the layer, a rubber-coated organic fiber cord is tilted to the center line of the bead core in a transverse section and is spirally coiled, in which each organic fiber cord in an inner and outer adjacent reinforcement layers over the bead core extends such that an organic fiber cord in the inner reinforcement layer and an organic fiber cord in the outer reinforcement layer intersect each other relative to the center line of the bead core in the transverse section, in which in the inner reinforcement layer, the cord is coiled with space at least partially in a tire circumferential direction such that the cord does not overlap in the tire circumferential direction, and the outer reinforcement layer is arranged to cover at least a part of the space.

Provided is a pneumatic tire having laminated reinforcement layers with organic fiber over a polygonal cross-section bead core, and in the layer, a rubber-coated organic fiber cord is tilted to the center line of the bead core in a transverse section and is spirally coiled, in which each organic fiber cord in an inner and outer adjacent reinforcement layers over the bead core extends such that an organic fiber cord in the inner reinforcement layer and an organic fiber cord in the outer reinforcement layer intersect each other relative to the center line of the bead core in the transverse section, in which in the inner reinforcement layer, the cord is coiled with space at least partially in a tire circumferential direction such that the cord does not overlap in the tire circumferential direction, and the outer reinforcement layer is arranged to cover at least a part of the space.

A tire for a heavy vehicle with a radial carcass reinforcement anchored in two beads by wrapping around bead wires. In a radial plane, radially on the inside of the radially innermost point of the at least one layer of carcass reinforcement and axially on the outside of the geometric center of the bead wire, the radius of curvature at a point on the exterior surface of the bead is greater than the radius of curvature at the point of orthogonal projection of the point of the exterior surface of the bead onto the at least one layer of carcass reinforcement.

Provided is a pneumatic radial tire for an aircraft including a bead core, a radial carcass and a stiffener, the radial carcass including one or more turn-up plies and one or more down plies, wherein in tire axial direction cross-sectional view, when an intersection point of a virtual circle with a ply closest to a tire axial direction inner side of the stiffener among the plies intersecting with the virtual circle having a radius that is twice as large as a diameter D of the bead core from a center O of the bead core is a point A, an intersection point of the virtual circle with a ply closest to a tire axial direction outer side of the stiffener is a point B, and a midpoint between the point A and the point B is a reference point C, then a line segment OC connecting the center O of the bead core to the reference point C has an inclination angle θ of 17° or less to a tire radial direction line passing the center O of the bead core on the tire axial direction outer side.