Patent ID: 9027612
Filing Date: 2015-05-12
Classification: B60C

Abstract:
1. A pneumatic tire whose rotational direction is specified as one direction, the pneumatic tire having a tread surface provided with a plurality of circumferential-direction grooves each extending in a tire circumferential direction, and with lateral grooves each extending in a tire widthwise direction, and including first lateral grooves and second lateral grooves being alternately arranged in the tire circumferential direction at a predetermined pitch, wherein the second lateral grooves are shorter in lengths compared to lengths of the first lateral grooves, thereby to include a rib formed on a tire equatorial plane in the tread surface and demarcated by the circumferential-direction grooves, and blocks formed in shoulder regions in the tread surface and demarcated by the circumferential-direction grooves and the lateral grooves, wherein the said second lateral grooves terminate at the blocks adjacent to said rib, the pneumatic tire is provided with three-dimensionally shaped sipes extending in the tire widthwise direction and arranged in the tire circumferential direction at predetermined intervals in the rib, each of the blocks further includes three-dimensionally shaped sipes arranged substantially parallel to each other and also parallel to the sipes arranged in immediately adjacent blocks; wherein: the sipes provided in the rib are each formed in a three-dimensional shape and extend zigzaggedly in a depth direction, and the rib is configured such that an amount at which the rib collapses, when an external force in the tire circumferential direction acts on the rib, is smaller in the tire rotational direction than in a direction opposite to the tire rotational direction; the sipes provided in each block include sipes provided in a block tread-in side portion situated in a side of the block in the tire rotational direction, and sipes provided in a block kick-out side portion situated in a side of the block in the direction opposite to the tire rotational direction; the sipes in the block tread-in side portion are each formed in such a three-dimensional shape that an amount at which the block, if entirely provided with the sipes, collapses when an external force in the tire circumferential direction acts on the block will be smaller in the tire rotational direction than in the direction opposite to the tire rotational direction; and the sipes in the block kick-out side portion are each formed in such a three-dimensional shape that an amount at which the block, if entirely provided with the sipes, collapses when an external force in the tire circumferential direction acts on the block will be smaller in the direction opposite to the tire rotational direction than in the tire rotational direction.