TECHNICAL FIELD

This disclosure relates to pneumatic tires.

BACKGROUND

A conventional pneumatic tire is known to have a carcass extending toroidally between a pair of bead portions, a belt formed by at least one belt layer disposed outward in the tire radial direction of the carcass, and a tread disposed outward in the tire radial direction of the belt, in which the belt has an endless belt layer.

The endless belt layer is formed by, for example, treats, each being formed by covering a cord with rubber and directed so as to change its direction at both tire widthwise ends toward a tire width direction inner side such that it extends in zigzag fashion in the tire circumferential direction. In other words, each treat is formed by, for example, inclined portions and linear portions that are alternately repeated in the tire circumferential direction in the order of an inclined portion of 10° to 20° rising to the right with respect to the tire circumferential direction, a linear portion substantially parallel to the tire circumferential direction, an inclined portion of 10° to 20° rising to the left with respect to the tire circumferential direction, and a linear portion substantially parallel to the tire circumferential direction.

A pneumatic tire having such an endless belt is described in, for example, JP2012-179850A (PTL 1).

CITATION LIST

Patent Literature

JP2012-179850A

SUMMARY

Technical Problem

However, in a structure like a conventional endless belt layer in which each treat is arranged with linear portions provided at both tire widthwise ends, the longer the linear portions, the wider the overlapping portions where redundant parts of the treats overlap one another at the linear portions will be. Since overlapping portions have an increased thickness as a result of overlapping one another, such portions may be crushed during vulcanization, and cords in the belt layer may come into contact with one another, providing a starting point of separation between belt layers.

On the other hand, if the linear portions are made too short, a bent portion that continues from a linear portion to an inclined portion will be lifted or turned up, and deflection easily occurs. In order to avoid such deflection at a bent portion, it is necessary to deviate the inclination angle of each bent portion as much as possible along the tire circumferential direction (for example, 10° to 20° with respect to the tire circumferential direction), and, for example, due to overlapping with a belt layer in the circumferential direction disposed inward in the tire radial direction of the endless belt layer, the rigidity is concentrated in the tire circumferential direction, and uneven shoulder wear tends to occur at increased frequency.

That is, if the linear portions are made too short, the inclination angle of each inclined portion is considerably restricted.

It would thus be helpful to provide a pneumatic tire that can prevent the occurrence of wide overlapping portions where redundant parts of treats forming an endless belt layer overlap one another, and that can reduce the restriction on the inclination angle of inclined portions of the treats to increase the degree of freedom in design.

Solution to Problem

To achieve the above object, a pneumatic tire according to the present disclosure comprises: a carcass extending toroidally between a pair of bead portions; a belt formed by at least one belt layer disposed outward in a tire radial direction of the carcass; and a tread disposed outward in the tire radial direction of the belt, the belt layer comprising an endless belt layer having provided therein treats, each of the treats being formed by covering a cord with rubber and directed so as to change its direction at both tire widthwise ends toward a tire width direction inner side such that the treat extends in zigzag fashion in the tire circumferential direction, wherein in the endless belt layer, a front surface and a rear surface of each of the treats are reversed at both tire widthwise ends, and on at least one tire widthwise end of the treats, a treat reversal position at which front and rear surfaces of each of the treats are reversed is, at least partially in the tire circumferential direction, displaced in the tire width direction from another treat reversal position adjacent in tire circumferential direction.

Solution to Problem

According to the present disclosure, it is possible to provide a pneumatic tire that can eliminate the occurrence of wide overlapping portions where redundant parts of treats forming an endless belt layer overlap one another, and that can reduce the restriction on the inclination angle of inclined portions of the treats to increase the degree of freedom in design.

