Pneumatic tire

Patent metadata

Field	Value
Publication number	US-11235620-B2
Application number	US-201716497041-A
Country	US
Kind code	B2
Filing date	Dec 22, 2017
Priority date	Mar 30, 2016
Publication date	Feb 1, 2022
Grant date	Feb 1, 2022

Abstract

A pneumatic tire comprising a carcass 11 , at least one inclined belt layer 13 having a cord extending inclined at an angle of 30° or more relative to the tire circumferential direction, and a tread 15 arranged outward in the tire radial direction of the inclined belt layer 13 , wherein a circumferential cord layer 14 arranged inward in the tire radial direction of the tread 15 has a high-rigidity region and a low-rigidity region and the high-rigidity region has a lower negative ratio in a ground contact width of the tread 15 than the low-rigidity region.

First claim

The invention claimed is:

1. A pneumatic tire comprising a carcass toroidally extending between a pair of bead portions, at least one inclined belt layer arranged passing through a tire equator outward in the tire radial direction of a crown portion of the carcass, and having a cord extending inclined at an angle of 30° or more with respect to a tire circumferential direction, and a tread arranged outward in the tire radial direction of the inclined belt layer, wherein
at least one circumferential cord layer having a cord extending along the tire circumferential direction is arranged inward in the tire radial direction of the tread,
the circumferential cord layer has a high-rigidity region which is a region including the tire equator and in which the rigidity in the tire circumferential direction per unit width in the tire width direction is high, and a low-rigidity region which is a region on each side in the tire width direction of the high-rigidity region and in which the rigidity in the tire circumferential direction per unit width in the tire width direction is low,
the high-rigidity region has a lower negative ratio in a ground contact width of the tread than the low-rigidity region;
when W 1 denotes a width in the tire width direction of the entire circumferential cord layer, W 2 denotes a width in the tire width direction of the high-rigidity region, and D 1 and D 2 respectively denote the longer and the shorter among the distances in the tire width direction from each end in the tire width direction of the entire circumferential cord layer to each end in the tire width direction of the high-rigidity region on a side close to each end in the tire width direction of the circumferential cord layer,
W 2 /W 1 =0.2 to 0.7, and, D 1 /D 2 =2.0 to 8.0 are satisfied; and
the at least one inclined belt layer and the at least one circumferential cord layer are configured such that a rigidity of the tire is asymmetric with respect to the tire equator.

2. The pneumatic tire according to claim 1 , wherein
the circumferential cord layer satisfies 1500≥X≥750, where X is defined as X=Y×n×m×d, Y is a Young's modulus (GPa) of the cords, n is a number of cords implanted (cords/50 mm), m is a number of circumferential cord layers, and d is a cord diameter (mm).

3. The pneumatic tire according to claim 1 , further comprising an inner liner arranged on the tire inner surface, wherein an air permeation coefficient of a rubber composition constituting the inner liner arranged on the tire inner surface is set to 1.0×10-14 cc·cm/(cm2·s·cm Hg) to 6.5×10-10 cc·cm/(cm2·s·cm Hg).

4. A pneumatic tire comprising a carcass toroidally extending between a pair of bead portions, at least one inclined belt layer arranged outward in a tire radial direction of a crown portion of the carcass and having a cord extending inclined relative to a tire circumferential direction, and a tread arranged outward in the tire radial direction of the inclined belt layer, wherein
at least one circumferential cord layer having a cord extending along the tire circumferential direction is arranged inward in the tire radial direction of the tread,
the inclined belt layer includes at least a wide-width inclined belt layer having a relatively wide width in the tire width direction and a narrow-width inclined belt layer having a relatively narrow width in the tire width direction, both passing through the tire equator, and when an inclination angle relative to the tire circumferential direction of the cord of the wide-width inclined belt layer is θ 1 and an inclination angle relative to the tire circumferential direction of the cord of the narrow-width inclined belt layer is θ 2 ,
30°≤θ 1 ≤85°, 10°≤θ 2 ≤30°, and, θ 1 >θ 2 are satisfied,
the inclined belt layer has a high-rigidity region which is a region including the tire equator and in which the rigidity in the tire circumferential direction per unit width in the tire width direction is high, and a low-rigidity region which is a region on each side in the tire width direction of the high-rigidity region and in which the rigidity in the tire circumferential direction per unit width in the tire width direction is low, and
the high-rigidity region has a lower negative ratio in a ground contact width of the tread than the low-rigidity region;
wherein when W 1 denotes a width in the tire width direction of a widest-width inclined belt layer having the widest width in the tire width direction in the inclined belt layer, W 2 denotes a width in the tire width direction of a narrowest-width inclined belt layer having the narrowest width in the tire width direction in the inclined belt layer, and D 1 and D 2 respectively denote the longer and the shorter among the distances in the tire width direction from each end in the tire width direction of the widest-width inclined belt layer to each end in the tire width direction of the narrowest-width inclined belt layer on a side close to each end in the tire width direction of the widest-width inclined belt layer,
W 2 /W 1 =0.2 to 0.7, and, D 1 /D 2 =2.0 to 8.0 are satisfied; and
the at least one inclined belt layer and the at least one circumferential cord layer are configured such that a rigidity of the tire is asymmetric with respect to the tire equator.

5. The pneumatic tire according to claim 4 , wherein the circumferential cord layer satisfies 1500≥X≥750, where X is defined as X=Y×n×m×d, Y is a Young's modulus (GPa) of the cords, n is a number of cords implanted (cords/50 mm), m is a number of circumferential cord layers, and d is a cord diameter (mm).

6. The pneumatic tire according to claim 4 , further comprising an inner liner arranged on the tire inner surface, wherein an air permeation coefficient of a rubber composition constituting the inner liner arranged on the tire inner surface is set to 1.0×10-14 cc·cm/(cm2·s·cm Hg) to 6.5×10-10 cc·cm/(cm2·s·cm Hg).

Assignees

• Bridgestone Corp

Inventors

• Kuwayama Isao

Classifications

• B60C11/03

  Tread patterns · CPC title

• B60C11/033

  by the void or net-to-gross ratios of the patterns · CPC title

• B60C9/18

  Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers · CPC title

• Y02T10/86

  Optimisation of rolling resistance, e.g. weight reduction · CPC title

• B60C9/22 Primary

  the plies being arranged with all cords disposed along the circumference of the tyre · CPC title