Patent ID: 9174491
Filing Date: 2015-11-03
Classification: B60C,Y10T

Abstract:
1. A pneumatic tire for heavy loads having: a toroidal carcass extending from a pair of bead cores through side portions to a tread portion; a belt located on the outer side of the carcass in the tire radial direction; a tread rubber located on the outer side of the belt in the tire radial direction; and, a groove on a road contact surface of the tread rubber, wherein the tread rubber is formed by a base rubber layer located on the inner side of the tread rubber in the radial direction and a cap rubber layer located on the outer circumferential surface of the base rubber layer; the base rubber layer is formed with a rubber composition generating smaller heat as compared with the cap rubber layer; the cap rubber layer is formed with a rubber composition having excellent wear resistance as compared with the base rubber layer; distribution of volume of the base rubber layer in the tread width direction is formed so as to be equal to distribution of wear effective rubber volume of the tread rubber in the tread width direction, the wear effective rubber volume being expressed by the following expression; wear effective rubber volume=(1−negative ratio per unit width in the tread width direction)×unit width of the tread rubber in the tread width direction×groove depth×circumferential length; when a tread half width of the tread rubber is divided into four or more areas in the tread width direction, the wear effective rubber volume at the dividing positions decreases toward the outer side in the tread width direction, and the volume distribution of the base rubber layer is equal to the distribution of the wear effective rubber volume when viewed at the dividing positions, and the wear effective rubber volume has a maximum volume in a tread center position, and the wear effective rubber volume decreases continuously from the tread center position to the tread edge.