Pneumatic tire with tread having cap portion, base portion and conductive portion

摘要

A pneumatic tire has a tread rubber provided in an outer side of a carcass layer in a tread portion. the tread rubber has a cap portion which is formed by a non-conductive rubber and constructs a ground-contacting surface, a base portion which is provided in an inner side in the tire diametrical direction of the cap portion, and a conductive portion which is formed by a conductive rubber and extends in a thickness direction of the tread rubber so as to reach a bottom surface of the tread rubber from the ground-contacting surface. A thickness of the conductive portion is made relatively large in a center portion in the thickness direction of the tread rubber, and the thickness of the conductive portion is made relatively small in both end portions in the thickness direction of the tread rubber.

主权项

1. A pneumatic tire comprising:
a pair of bead portions; side wall portions each of which extends to an outer side in a tire diametrical direction from each of the bead portions; a tread portion which is connected to an outer end in the tire diametrical direction of each of the side wall portions; a toroidal carcass layer which is provided between the pair of the bead portions; and a tread rubber which is provided in an outer side of the carcass layer in the tread portion, wherein the tread rubber has
a cap portion which is formed by a non-conductive rubber and constructs a ground-contacting surface,a base portion which is provided in an inner side in the tire diametrical direction of the cap portion, anda conductive portion which is formed by a conductive rubber and extends in a thickness direction of the tread rubber so as to reach a bottom surface of the tread rubber from the ground-contacting surface, wherein a thickness of the conductive gradually increases from a first end in the thickness direction of the tread rubber to a center portion in the thickness direction of the tread rubber, wherein the thickness of the conductive portion gradually decreases from the center portion in the thickness direction of the thread rubber to a second end in the thickness direction of the thread rubber, and wherein the conductive portion is formed in an approximately crescent shape in a tire meridian cross-section.