Pneumatic tire and method for manufacturing the same

1. A pneumatic tire comprising:

a belt layer embedded in an outer circumferential side of a carcass layer; and

belt reinforcing layers embedded in an outer circumferential side of the belt layer so that at least one belt reinforcing layer of the belt reinforcing layers covers each of a tire width direction left edge portion and right edge portion of the belt layer, the at least one belt reinforcing layer covering the left edge portion being separated from the at least one belt reinforcing layer covering the right edge portion in the tire width direction, both longitudinal direction edges of each of the belt reinforcing layers being aligned perpendicular to a winding direction of the belt reinforcing layers; wherein

each of the belt reinforcing layers is formed by strip members constituting each of the belt reinforcing layers that are both inclined in a same direction with respect to a tire circumferential direction, and are wound in a spiral-like manner at least one time around in the tire circumferential direction;

a wide belt layer and a narrow belt layer which is narrower than the wide belt layer are embedded as the belt layer;

a tire width direction dimension of the strip members constituting each of the belt reinforcing layers is set to be larger than a protrusion part between the tire width direction edge of the narrow belt layer and the tire width direction edge of the wide belt layer, the protrusion part protruding outward in the tire width direction;

the strip members have a plurality of reinforcing cords which are parallel to the width direction of each of the belt reinforcing layers and extend in an extending direction of each of the belt reinforcing layers; and

each of the belt reinforcing layers is laminated so as to protrude outward in the tire width direction from an edge in the tire width direction of the wide belt layer and the narrow belt layer on a side where each of the belt reinforcing layers is laminated, and each of the belt reinforcing layers is a single layer.

2. The pneumatic tire according to claim 1 , wherein first longitudinal direction edges, of the longitudinal direction edges of the strip members constituting each of the belt reinforcing layers, positioned on a center portion side of the tire width direction are parallel with each other in the tire circumferential direction and a distance from one first longitudinal direction edge to another first longitudinal direction edge in the tire width direction remains constant along the tire circumferential direction; and second longitudinal direction edges, of the longitudinal direction edges of the strip members, positioned on an outer side of the tire width direction are parallel with each other in the tire circumferential direction and a distance from one circumferential direction edge to another circumferential direction edge, both of which extend in the tire circumferential direction of the belt reinforcing layers, in the tire width direction remains constant along the tire circumferential direction.

3. The pneumatic tire according to claim 2 , wherein an embedded number of each of the belt reinforcing layers is one.

4. The pneumatic tire according to claim 1 , wherein an embedded number of each of the belt reinforcing layers is one.

5. A method for manufacturing a pneumatic tire comprising:

molding a green tire having a structure constituted by belt reinforcing layers on an outer circumferential side of an annularly-formed belt layer so that at least one belt reinforcing layer of the belt reinforcing layers covers a tire width direction left edge portion and another at least one belt reinforcing layer of the belt reinforcing layers covers a tire width direction right edge portion of the annularly formed belt layer, the at least one belt reinforcing layer covering the left edge portion being separated from the another at least one belt reinforcing layer covering the right edge portion in the tire width direction, wherein both longitudinal direction edges of each of the belt reinforcing layers are aligned perpendicular to a winding direction of the belt reinforcing layers; and then

in the method for manufacturing the pneumatic tire in which the green tire is vulcanized, in a step of laminating each of the belt reinforcing layers, strip members constituting each of the reinforcing layers are inclined in a same direction with respect to a tire circumferential direction, and are wound in a spiral-like manner at least one time around in the tire circumferential direction; wherein

a wide belt layer and a narrow belt layer which is narrower than the wide belt layer are embedded as the belt layer;

a tire width direction dimension of the strip members constituting each of the belt reinforcing layers is set to be larger than a protrusion part between the tire width direction edge of the narrow belt layer and the tire width direction edge of the wide belt layer, the protrusion part protruding outward in the tire width direction;

the strip members have a plurality of reinforcing cords which are parallel to each other and extend in the extending direction of each of the belt reinforcing layers; and

each of the belt reinforcing layers is laminated so as to protrude outward in the tire width direction from an edge in the tire width direction of the wide belt layer and the narrow belt layer on a side where each of the belt reinforcing layers is laminated, and each of the belt reinforcing layers is a single layer.

6. The method for manufacturing a pneumatic tire according to claim 5 , wherein first longitudinal direction edges, of the longitudinal direction edges of the strip members constituting each of the belt reinforcing layers, positioned on a center portion side of the tire width direction are parallel with each other in the tire circumferential direction; and second longitudinal direction edges, of the longitudinal direction edges of the strip members constituting each of the belt reinforcing layers, positioned on an outer side of the tire width direction are parallel with each other in the tire circumferential direction and a distance from one circumferential direction edge of a first of the strip members to another circumferential direction edge of a second of the strip members, both of which extend in the tire circumferential direction of the belt reinforcing layers, in the tire width direction remains constant along the tire circumferential direction.

7. The method for manufacturing a pneumatic tire according to claim 6 , wherein:

while rotating the annularly-formed belt layer in a first direction of the circumferential direction, a winding start point of a first of the strip members is set farther to the center portion side of the tire width direction than a winding termination point, and the first strip member is wound in a spiral-like manner at least one time around in the tire circumferential direction; and

while rotating the annularly-formed belt layer in the same first direction of the circumferential direction, a winding start point of a second of the strip members is set farther to the outer side of the tire width direction than a winding termination point, and the second strip member is wound in a spiral-like manner at least one time around in the tire circumferential direction.

8. The method for manufacturing a pneumatic tire according to claim 5 , wherein:

while rotating the annularly-formed belt layer in a first direction of the circumferential direction, a winding start point of a first of the strip members is set farther to a center portion side of the tire width direction than a winding termination point, and the first strip member is wound in a spiral-like manner at least one time around in the tire circumferential direction; and

while rotating the annularly-formed belt layer in a direction opposite to the first direction of the circumferential direction, a winding start point of a second of the strip members is set farther to the center portion side of the tire width direction than a winding termination point, and the second strip member is wound in a spiral-like manner at least one time around in the tire circumferential direction.

9. The method for manufacturing a pneumatic tire according to claim 5 , wherein:

while rotating the annularly-formed belt layer in a first direction of the circumferential direction, a winding start point of a first of the strip members is set farther to a center portion side of the tire width direction than a winding termination point, and the first strip member is wound in a spiral-like manner at least one time around in the tire circumferential direction; and

while rotating the annularly-formed belt layer in the same first direction of the circumferential direction, a winding start point of a second of the strip members is set farther to the outer side of the tire width direction than a winding termination point, and the second strip member is wound in a spiral-like manner at least one time around in the tire circumferential direction.