Pneumatic heavy-duty tire having circumferential reinforcing layer and sipes

摘要

In the pneumatic tire, the blocks above the circumferential reinforcing layer have at least one sipe. Also, the sipe has a bent shape, in a plan view, with two flex points P1, P2, and has a closed structure with two end points Q1, Q2 terminating within the block. Also, the angle α between the line that connects the flex points P1, P2 and the tire circumferential direction is within the range such that 0°≦α≦10°. Also, the angle β1 between the line connecting the flex point P1 and the end point Q1 and the tire circumferential direction, and the angle β2 between the line connecting the flex point P2 and the end point Q2 and the tire circumferential direction are within the range such that 35°≦β1≦55° and 35°≦β2≦55°.

主权项

1. A pneumatic tire comprising: a belt layer that includes a circumferential reinforcing layer; a plurality of circumferential main grooves; and a plurality of land portions partitioned by the circumferential main grooves, wherein
the pneumatic tire is a heavy-duty tire, the land portions above the circumferential reinforcing layer have at least one sipe, the at least one sipe has a bent shape with two flex points P1, P2 in a plan view, and a closed structure with two end points Q1, Q2 that terminate within the land portion, an angle α between a line that connects the flex points P1, P2 and a tire circumferential direction is within a range such that 0°≦α≦10°, an angle β1 between a line connecting the flex point P1 and the end point Q1 and the tire circumferential direction, and an angle β2 between a line connecting the flex point P2 and the end point Q2 and the tire circumferential direction are within a range such that 35°≦β1≦55° and 35°≦β2≦55°, a length S1 of the line connecting the flex point P1 and the end point Q1, a length S2 of the line connecting the flex point P2 and the end point Q2, and a length L1 in the tire circumferential direction of the line connecting the flex points P1, P2 have a relationship such that 0.50≦S1/L1≦0.70 and 0.50≦S2/L1≦0.70, a width W1 in a tire width direction of the sipe and a width W2 in the tire width direction of the land portion having the sipe have a relationship such that W1/W2≦0.20, a depth D1 of the sipe gradually decreases towards the end points Q1, Q2, the circumferential reinforcing layer is disposed on an inner side in the tire width direction from left and right edge portions of a narrower cross belt of a pair of cross belts, and a width W of the narrower cross belt and a width Ws of the circumferential reinforcing layer are within a range such that 0.60≦Ws/W.