Patent ID: 8967214
Filing Date: 2015-03-03
Classification: B60C,Y10T

Abstract:
1. A pneumatic radial tire comprising: a carcass ply which extends between bead cores arranged in a pair of bead portions, and is turned up to an outer side in a tire radial direction around the bead cores; and a chafer which is arranged around the bead cores in such a manner as to enwrap the carcass ply from an inner side to an outer side in a tire width direction, wherein a wind-up side cord of the chafer positioned in the inner side in the tire width direction is arranged in such a manner that an angle of inclination of a first straight line with respect to a tire circumferential direction is 20 to 40 degrees, the first straight line connecting a first intersecting point intersecting with a tire circumferential line passing through a position which is 7 mm inside in the tire radial direction from an inner end of the chafer, and a second intersecting point intersecting with a tire circumferential line passing through an innermost end in the tire width direction of the bead core, and is formed as a circular arc shape which is convex to an outer side in the tire radial direction between the first intersecting point and the second intersecting point, wherein a turn-up side cord of the chafer positioned in the outer side in the tire width direction is arranged in such a manner that an angle of inclination of a second straight line with respect to the tire circumferential direction is 30 to 50 degrees, the second straight line connecting a third intersecting point intersecting with a tire circumferential line passing through a position which is 7 mm inside in the tire radial direction from an outer end of the chafer, and a fourth intersecting point intersecting with the tire circumferential line passing through the innermost end in the tire width direction of the bead core, and is equal to or less than 5 degrees in a change of the angle of inclination with respect to the tire circumferential direction between the third intersecting point and the fourth intersecting point, and wherein a tire circumferential line passing through a position which is 20 mm outside in the tire radial direction from the second intersecting point intersects with the wind-up side cord at a fifth intersecting point, and a distance in the tire circumferential direction from the fifth intersecting point to the first straight line is equal to or more than 2 mm and equal to or less than 12 mm.