| CPC B60C 11/0083 (2013.01) [B60C 11/005 (2013.01); B60C 11/0327 (2013.01); B60C 2011/0025 (2013.01); B60C 2011/0033 (2013.01)] | 19 Claims |
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1. A tire comprising:
a tread configured to come into contact with a road surface,
wherein an outer surface of the tire comprises a tread surface and a pair of side surfaces continuous with ends of the tread surface,
wherein, on a meridian cross-section of the tire, a contour of the tread surface comprises a plurality of curved contour lines formed as arcs having different radii,
wherein a contour of the outer surface of the tire comprises, in each of end portions of the tread surface, a curved line portion that is formed as a curved contour line connected to a corresponding one of the side surfaces and is formed as an arc having a smallest radius among the plurality of curved contour lines included in the contour of the tread surface, an inner adjacent contour line disposed inwardly of the curved line portion in an axial direction in contact with the curved line portion, and an outer adjacent contour line disposed outwardly of the curved line portion in the axial direction in contact with the curved line portion,
wherein a tread reference end is an intersection point of the outer surface of the tire, and a straight line extending in a radial direction through an intersection point of a line tangent to the curved line portion at a contact point at which the inner adjacent contour line and the curved line portion are in contact with each other, and a line tangent to the curved line portion at a contact point at which the outer adjacent contour line and the curved line portion are in contact with each other,
wherein an axial distance from an equator plane to the tread reference end is a tread half-width,
wherein the tread comprises a cap layer forming a part of the outer surface of the tire, an intermediate layer disposed inwardly of the cap layer in the radial direction, and a base layer disposed inwardly of the intermediate layer in the radial direction,
wherein a loss tangent of the intermediate layer at 30° C. is less than a loss tangent of the cap layer at 30° C., and a loss tangent of the base layer at 30° C. is less than the loss tangent of the intermediate layer at 30° C.,
wherein an outer end of the cap layer is disposed outwardly of an outer end of the base layer in the axial direction,
wherein a position of the outer end of the cap layer coincides with a position of the outer end of the base layer in the radial direction, or the outer end of the cap layer is disposed inwardly of the outer end of the base layer in the radial direction,
wherein a ground contact surface obtained by mounting the tire on a normal rim, adjusting an internal pressure of the tire to a normal internal pressure, applying a load that is 70% of a normal load, to the tire, as a vertical load, and bringing the tire into contact with a planar road surface, is a reference ground contact surface,
wherein half a ground contact width of the reference ground contact surface is a ground contact half-width,
wherein a portion formed of the cap layer in the outer surface of the tire is a cap surface,
wherein an outer end of the cap surface is disposed outwardly of the tread reference end in the axial direction, and
wherein, on a meridian cross-section of the tire, a ratio of a total of the tread half-width and a length, measured along the outer surface of the tire, from the tread reference end to the outer end of the cap surface, relative to the ground contact half-width, is not less than 1.15 and not greater than 1.20.
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19. A tire comprising:
a tread configured to come into contact with a road surface,
wherein an outer surface of the tire comprises a tread surface and a pair of side surfaces continuous with ends of the tread surface,
wherein, on a meridian cross-section of the tire, a contour of the tread surface comprises a plurality of curved contour lines formed as arcs having different radii,
wherein a contour of the outer surface of the tire comprises, in each of end portions of the tread surface, a curved line portion that is formed as a curved contour line connected to a corresponding one of the side surfaces and is formed as an arc having a smallest radius among the plurality of curved contour lines included in the contour of the tread surface, an inner adjacent contour line disposed inwardly of the curved line portion in an axial direction in contact with the curved line portion, and an outer adjacent contour line disposed outwardly of the curved line portion in the axial direction in contact with the curved line portion,
wherein a tread reference end is an intersection point of the outer surface of the tire, and a straight line extending in a radial direction through an intersection point of a line tangent to the curved line portion at a contact point at which the inner adjacent contour line and the curved line portion are in contact with each other, and a line tangent to the curved line portion at a contact point at which the outer adjacent contour line and the curved line portion are in contact with each other,
wherein an axial distance from an equator plane to the tread reference end is a tread half-width,
wherein the tread comprises a cap layer forming a part of the outer surface of the tire, an intermediate layer disposed inwardly of the cap layer in the radial direction, and a base layer disposed inwardly of the intermediate layer in the radial direction,
wherein a loss tangent of the intermediate layer at 30° C. is less than a loss tangent of the cap layer at 30° C., and a loss tangent of the base layer at 30° C. is less than the loss tangent of the intermediate layer at 30° C.,
wherein an outer end of the cap layer is disposed outwardly of an outer end of the base layer in the axial direction,
wherein a position of the outer end of the cap layer coincides with a position of the outer end of the base layer in the radial direction, or the outer end of the cap layer is disposed inwardly of the outer end of the base layer in the radial direction,
wherein a thickness of the intermediate layer increases as it extends towards the tread reference end in the axial direction, and
wherein a thickness of the base layer decreases as it extends towards the tread reference end in the axial direction.
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