Patent ID: 7543617
Filing Date: 2009-06-09
Classification: B60C

Abstract:
1. A pneumatic tire comprising: a longitudinal main groove formed concavely on a tread surface thereof in a radial direction thereof by extending said longitudinal main groove linearly in a circumferential direction thereof; wherein narrow grooves are formed concavely on at least an outer side surface of side surfaces of said longitudinal main groove opposed to each other in a widthwise direction of said pneumatic tire, with a bottom surface of said longitudinal main groove interposed between said side surfaces, said narrow grooves being spaced at certain intervals in a circumferential direction of said pneumatic tire; a length of each of said narrow grooves in the radial direction of said pneumatic tire is set to 100% of a depth of the longitudinal main groove; each of said narrow grooves linearly extends in a direction between a bottom surface of said longitudinal main groove and a grounding surface of a tread surface; a portion of a side surface of said longitudinal main groove where said narrow grooves are not formed has an arc-shape that projects toward an opposed side surface of said longitudinal main groove; said side surface of said longitudinal main groove is continued with the grounding edge of said surface of said longitudinal main groove; said grounding edge of the side surface of said longitudinal main groove and side edge of the bottom surface of said longitudinal main groove are linearly continuous in a circumferential direction of the pneumatic tire; an opening of each of said narrow grooves formed in a side surface of said longitudinal main groove has a shape that is elliptic or oblong in the radial direction of the pneumatic tire; a bottom surface of each of said narrow grooves in said radial direction of said pneumatic tire is circular arc-shaped and is continuous with an edge of said bottom surface of said longitudinal main groove and with a grounding edge of said tread surface; a grounding edge of a side surface of said longitudinal main groove is linearly continuous in said circumferential direction of said pneumatic tire; wherein each of said narrow grooves is so configured that a longer side of each of said narrow grooves extends in said radial direction of said pneumatic tire or in the same direction as a depth direction of said longitudinal main groove and that a shorter side of each of said narrow grooves extends in said circumferential direction of said pneumatic tire orthogonal to said radial direction of said pneumatic tire; and a sectional configuration of a position having a maximum sectional area in each of said narrow grooves is circular arc-shaped.