Patent ID: 11926176
Assignee: BRIDGESTONE CORPORATION
Field: Transport (Mechanical engineering)
Classification: CPC B | IPC B

Claim 0:
1. A pneumatic tire comprising, on a tread surface, a plurality of circumferential main grooves extending in a tread circumferential direction, and a plurality of land portions, each land portion being defined between circumferential main grooves adjacent in a tread width direction among the plurality of circumferential main grooves, or by the circumferential main groove and a tread edge, wherein
the land portion includes a plurality of widthwise grooves extending in the tread width direction and a plurality of widthwise sipes extending in the tread width direction,
the widthwise groove includes a gradually decreasing groove width portion in which the groove width gradually decreases from the tread surface towards an inner side in a tire radial direction, a constant groove width portion that extends from the gradually decreasing groove width portion towards the inner side in the tire radial direction and has a constant groove width, and a branched groove portion that branches and extends from the constant groove width portion towards the inner side in the tire radial direction,
each widthwise sipe includes a gradually decreasing sipe width portion in which a sipe width gradually decreases from the tread surface towards an inner side in the tire radial direction, a constant sipe width portion that extends from the gradually decreasing sipe width portion towards the inner side in the tire radial direction and has a constant sipe width, and a branched sipe portion that branches and extends from the constant sipe width portion towards the inner side in the tire radial direction,
the branched groove portion is formed by two branched grooves,
an intersection between the two branched grooves is rounded on the inner side in the tire radial direction,
the branched sipe portion is formed by two branched sipes,
an intersection between the two branched sipes is rounded on the inner side in the tire radial direction, and
a radius of curvature of rounding on the inner side in the tire radial direction of the intersection between the two branched grooves is smaller than a radius of curvature of rounding on the inner side in the tire radial direction of the intersection between the two branched sipes.