Pneumatic tire

Patent metadata

Field	Value
Publication number	US-12377683-B2
Application number	US-202318372229-A
Country	US
Kind code	B2
Filing date	Sep 25, 2023
Priority date	Oct 21, 2022
Publication date	Aug 5, 2025
Grant date	Aug 5, 2025

Abstract

A pneumatic tire includes a tread portion, a pair of sidewall portions, a pair of bead portions, a carcass extending between the pair of bead portions, and an inner rubber extending between the pair of bead portions on an inner side of the carcass. The inner rubber includes a first portion extending in the tread portion with a first thickness and a second portion extending in each of or one of the pair of sidewall portions with a second thickness. The first thickness is greater than the second thickness. In a tire meridian cross-section, a cross-sectional area of the inner rubber is in a range from 1.5% to 10% of an inner-cavity cross-sectional area of the pneumatic tire.

First claim

The invention claimed is:

1. A pneumatic tire comprising:
a tread portion;
a pair of sidewall portions;
a pair of bead portions;
a carcass extending between the pair of bead portions;
a belt layer arranged outside the carcass in a tire radial direction; and
an inner rubber extending between the pair of bead portions on an inner side of the carcass; wherein
the inner rubber comprises a first portion extending in the tread portion with a first thickness and a second portion extending in each of or one of the pair of sidewall portions with a second thickness,
the first thickness is greater than the second thickness,
the first thickness and the second thickness are measured from an inner surface of the carcass to a tire inner cavity surface,
in a tire meridian cross-section, a cross-sectional area of the inner rubber is in a range from 1.5% to 10% of an inner-cavity cross-sectional area of the pneumatic tire,
the tread portion comprises a first tread edge, a tire equator, a first shoulder circumferential groove arranged between the tire equator and the first tread edge,
the first portion of the inner rubber has an outer end in a tire axial direction on a first tread edge side with respect to the tire equator,
the outer end of the first portion is located outwardly in the tire axial direction of the first shoulder circumferential groove and between the first shoulder circumferential groove and an outer end on the first tread edge side of the belt layer,
the first portion includes a first end portion on the first tread edge side,
in the first end portion, the first thickness continuously decreases toward the outer end of the first portion,
a position at which the decrease of the first thickness ends corresponds to the outer end of the first portion, and
a loss tangent tan δ 1 of the first portion at 70 degrees C. is equal to or more than 1.1 times and equal to or less than 1.5 times the loss tangent tan δ 2 of the second portion at 70 degrees C.

2. The pneumatic tire according to claim 1 , wherein an average value of the first thickness is in a range from 1.5 to 3.5 times an average value of the second thickness.

3. The pneumatic tire according to claim 1 , wherein the average value of the first thickness is in a range from 2.0 to 4.5 mm.

4. The pneumatic tire according to claim 1 , wherein
a cross-sectional width of the tire is in a range from 205 to 325 mm,
as aspect ratio of the tire is in a range from 25% to 65%, and
a rim diameter on which the pneumatic tire is to be mounted is in a range from 16 to 22 inches.

5. The pneumatic tire according to claim 1 , wherein
the tread portion comprises a tread rubber forming a ground contact surface, and
the loss tangent δ 1 is equal to or greater than a loss tangent tan δA of the tread rubber at 30 degrees C.

6. The pneumatic tire according to claim 1 , wherein
the tread comprises a plurality of circumferential grooves extending continuously in a tire circumferential direction, and
a maximum value of the first thickness of the first portion is in a range from 0.25 to 0.60 times a maximum value of groove depths of the plurality of circumferential grooves.

7. The pneumatic tire according to claim 6 , wherein
the tread portion comprises a plurality of circumferential grooves extending continuously in a tire circumferential direction, and
a volume of the inner rubber is in a range from 0.30 to 0.50 times a volume of the tread rubber.

8. The pneumatic tire according to claim 6 , wherein
the first portion is made of a composite of an air-impermeable rubber material and an air-permeable rubber material.

9. The pneumatic tire according to claim 1 , wherein
an outer diameter of the tire is equal to or more than 660 mm in a normal state that the tire is mounted on a standard wheel rim with normal internal pressure but loaded with no tire load,
the tread portion comprises a plurality of circumferential grooves extending continuously in a tire circumferential direction, and
a total groove width of the plurality of circumferential grooves is in a range from 25% to 30% of a tread width of the tread portion.

10. The pneumatic tire according to claim 9 , wherein a cross-sectional width of the tire in a normal state is equal to or more than 225 mm.

11. The pneumatic tire according to claim 10 , wherein a length in a tire axial direction of the first portion is in a range from 65% to 85% of the cross-sectional width.

12. The pneumatic tire according to claim 9 , wherein the first thickness is equal to or more than 0.45% of the outer diameter of the tire.

13. The pneumatic tire according to claim 1 , wherein
the carcass comprises carcass cords, and
the carcass cords have a twist coefficient in a range from 2000 to 2500.

14. The pneumatic tire according to claim 13 , wherein
the tread portion comprises a tread rubber forming a ground contact surface, and
the loss tangent tan δ 1 of the first portion at 70 degrees C. is equal to or less than a loss tangent tan δA of the tread rubber at 30 degrees C.

15. The pneumatic tire according to claim 14 , wherein
the loss tangent δ 1 of the first portion is in a range from 0.4 to 0.7 times the loss tangent tan δA of the tread rubber.

16. The pneumatic tire according to claim 8 , wherein the air-permeable rubber material has a loss tangent tan δ larger than a loss tan δ of the air-impermeable rubber material.

17. The pneumatic tire according to claim 1 , wherein
the belt layer includes a first belt ply adjacent to the carcass and a second belt ply arranged radially outside the first belt ply,
the second belt ply has a length in the tire axial direction smaller than a length in the tire axial direction of the first belt ply,
the outer end of the first portion is located between the first shoulder circumferential groove and an outer end on the first tread edge side of the second belt ply.

18. A pneumatic tire comprising:
a tread portion;
a pair of sidewall portions;
a pair of bead portions;
a carcass extending between the pair of bead portions; and
an inner rubber extending between the pair of bead portions on an inner side of the carcass; wherein
the inner rubber comprises a first portion extending in the tread portion with a first thickness and a second portion extending in each of or one of the pair of sidewall portions with a second thickness,
the first thickness is greater than the second thickness,
the first thickness and the second thickness are measured from an inner surface of the carcass to a tire inner cavity surface,
in a tire meridian cross-section, a cross-sectional area of the inner rubber is in a range from 1.5% to 10% of an inner-cavity cross-sectional area of the pneumatic tire,
the tread portion comprises a plurality of circumferential grooves extending continuously in a tire circumferential direction and a tread rubber forming a ground contact surface,
a maximum value of the first thickness of the first portion is in a range from 0.25 to 0.60 times a maximum value of groove depths of the plurality of circumferential grooves,
a volume of the inner rubber is in a range from 0.30 to 0.50 times a volume of the tread rubber, and
a loss tangent tan δ 1 of the first portion at 70 degrees cis equal to or more than 1.1 times and equal to or less than 1.5 times the loss tangent tan δ 2 of the second portion at 70 degrees C.

19. A pneumatic tire comprising:
a tread portion;
a pair of sidewall portions;
a pair of bead portions;
a carcass extending between the pair of bead portio

Assignees

• Sumitomo Rubber Ind

Inventors

• Imai Daiki
• Onitsuka Rena
• Yuan Suxiang
• Sueno Junya

Classifications

• B60C2011/0341

  Circumferential grooves · CPC title

• B60C2011/0025

  Modulus or tan delta · CPC title

• B60C11/03

  Tread patterns · CPC title

• B60C3/04

  characterised by the relative dimensions of the section, e.g. low profile (B60C3/06 takes precedence) · CPC title

• B60C2011/0355

  characterised by depth · CPC title