| CPC B60C 11/1376 (2013.01) [B60C 11/0304 (2013.01); B60C 11/1218 (2013.01); B60C 11/0306 (2013.01); B60C 2011/0381 (2013.01); B60C 2011/1213 (2013.01); B60C 2011/1227 (2013.01)] | 14 Claims |
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1. A pneumatic tire comprising a tread portion, the tread portion comprising:
an intermediate land portion delimited by two circumferential main grooves in a tire lateral direction, the intermediate land portion being positioned on one side in the tire lateral direction with a tire center line as a boundary; and
a side land portion adjoining an outer circumferential main groove of the two circumferential main grooves, the side land portion being provided outside the outer circumferential main groove in the tire lateral direction, and including a ground contact edge of the pneumatic tire within a region thereof,
the tread portion having, in a profile cross section of at least one land portion of the intermediate land portion and the side land portion along the tire lateral direction, a swelling profile line that protrudes outward in a tire radial direction with respect to a base profile line that is an arc of a circle having a center point positioned on the tire center line and passing through at least two land portion edge points at which the intermediate land portion is connected to the two circumferential main grooves and one side land portion edge point at which the side land portion is connected to the outer circumferential main groove,
the tread portion being provided with a plurality of sipes extending in the tire lateral direction at an interval in a tire circumferential direction in a region of a swelling land portion formed in the swelling profile line in the intermediate land portion or the side land portion,
the plurality of sipes comprising:
first sipes having a shape extending linearly from the tread surface in a sipe depth direction and being opened to an inner circumferential main groove of the two circumferential main grooves; and
second sipes being bent or curved in a wave manner and protruding in a direction orthogonal to the sipe depth direction and orthogonal to an extension direction in which the plurality of sipes extend on the tread surface, when advancing from the tread surface in the sipe depth direction,
the plurality of sipes being composite sipes each formed by one of the first sipes and one of the second sipes connected each other in the extension direction, and
the second sipes being positioned on a side of the outer circumferential main groove with respect to the first sipes in the swelling land portion, and the second sipes being opened to the outer circumferential main groove; wherein
lengths of the composite sipes in the tire lateral direction are 40% or more of a length of a contact region in contact with a road surface in the swelling land portion in the tire lateral direction,
lengths of the second sipes in the extension direction fall within a range of from 30% to 80% of the lengths of the composite sipes in the extension direction, and
the second sipes do not include a linearly extending portion in the sipe depth direction.
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