Pneumatic tire

Patent metadata

Field	Value
Publication number	US-12330451-B2
Application number	US-202218286444-A
Country	US
Kind code	B2
Filing date	Mar 9, 2022
Priority date	Apr 22, 2021
Publication date	Jun 17, 2025
Grant date	Jun 17, 2025

Abstract

A pneumatic tire comprises a tread portion provided with a band layer disposed radially inside a tread rubber provided with a first circumferential groove. Cords of the band layer are a hybrid cord formed by twisting together a first filament and a second filament having an elastic modulus lower than that of the first filament. In a region radially inside the first circumferential groove, a maximum thickness t 1 of topping rubber on the radially outer side of the band cords is not more than 1.0 mm; a minimum distance d 1 from the bottom of the first circumferential groove to the radially outer surface of the band layer is not more than 2.0 mm; and a distance d 2 from a groove edge of the first circumferential groove to the radially outer surface of the band layer is not more than 15.0 mm.

First claim

The invention claimed is:

1. A pneumatic tire having a tread portion, wherein
the tread portion comprises a tread rubber forming a ground contacting surface, and a band layer disposed radially inside the tread rubber,
the tread rubber is provided with a first circumferential groove extending continuously in the tire circumferential direction in the ground contacting surface,
the band layer comprises band cords arranged substantially parallel to the tire circumferential direction, and a topping rubber covering the band cords,
wherein
the band cords are each formed by twisting together a first yarn and a second yarn,
the first yarn is formed by twisting first filaments together,
the second yarn is formed by twisting second filaments together,
an elastic modulus of each of the second filaments is lower than an elastic modulus of each of the first filaments,
the first filaments and the second filaments are formed from organic fibers,
a total fineness of each band cord is not more than 4400 dtex,
a stress σ 1 of each band cord when elongated by 3% is not more than 0.03 (N/tex), and a stress σ 2 of the band cord when elongated by 5% is 0.04 to 0.06 (N/tex), wherein the stress σ 1 and the stress σ 2 are measured by a method specified in Japanese Industrial Standards (JIS) L1017,
in a region radially inside the first circumferential groove, a maximum thickness t 1 of the topping rubber on the radially outer side of the band cords is not more than 1.0 mm,
a minimum distance d 1 from the bottom of the first circumferential groove to the radially outer surface of the band layer is not more than 2.0 mm, and
a distance d 2 in a tire normal direction from a groove edge of the first circumferential groove to the radially outer surface of the band layer is not more than 15.0 mm.

2. The pneumatic tire according to claim 1 , wherein
a sea ratio of the ground contacting surface of the tread portion is 15% to 50%, and
a ratio σ 1 /σ 2 (%) of the stress σ 1 (N/tex) at 3% elongation of the band cord to the stress σ 2 (N/tex) at 5% elongation of the band cord is greater than the sea ratio (%) of the ground contacting surface of the tread portion.

3. The pneumatic tire according to claim 1 , wherein the thickness t 1 is 0.05 to 0.30 mm, the distance d 1 is 0.5 to 1.5 mm, and the distance d 2 is 5.0 to 12.0 mm.

4. The pneumatic tire according to claim 1 , wherein a sea ratio of the ground contacting surface of the tread portion is 15% to 50%.

5. The pneumatic tire according to claim 4 , wherein a ratio t 1 /d 1 (%) between the thickness t 1 and the distance d 1 is smaller than the shear sea ratio (%).

6. The pneumatic tire according to claim 1 , wherein the tread rubber includes a rubber compound having a complex elastic modulus E* 1 of not more than 10 (MPa) at 30 degrees C.

7. The pneumatic tire according to claim 6 , wherein
a sea ratio of the ground contacting surface of the tread portion is 15% to 50%, and
a product of the complex elastic modulus E* 1 (MPa) and the sea ratio (%) of the ground contacting surface of the tread portion is not more than 5.0 (MPa).

8. The pneumatic according to claim 6 , wherein a product d 1 ·E* 1 of the distance d 1 (mm) and the complex elastic modulus E* 1 (MPa) is 5.0 to 30.0 (MPa·mm).

9. The pneumatic tire according to claim 8 , wherein product σ 2 ·E* 1 of the stress σ 2 (N/tex) at 5% elongation of the band cord and the complex elastic modulus E* 1 (MPa) is 0.40 to 1.60 (N·MPa/tex).

10. The pneumatic tire according to claim 1 , wherein a product σ 1 ·d 2 of the stress σ 1 (N/tex) and the distance d 2 (mm) is 0.05 to 0.40 (N·mm/tex).

11. The pneumatic tire according to claim 5 , wherein a product σ 2 ·d 2 of the stress σ 2 (N/tex) and the distance d 2 (mm) is 0.30 to 0.60 (N·mm/tex).

12. The pneumatic tire according to claim 11 , wherein
a sea ratio of the ground contacting surface of the tread portion is 15% to 50%, and
a ratio σ 1 /σ 2 (%) of the stress σ 1 (N/tex) at 3% elongation of the band cord to the stress σ 2 (N/tex) at 5% elongation of the band cord is greater than the sea ratio (%) of the ground contacting surface of the tread portion.

13. The pneumatic tire according to claim 11 , wherein
the tread rubber includes a rubber compound having a complex elastic modulus E* 1 of not more than 10 (MPa) at 30 degrees C.,
a product d 1 ·E* 1 of the distance d 1 (mm) and the complex elastic modulus E* 1 (MPa) is 5.0 to 30.0 (MPa·mm), and
a product σ 2 ·E* 1 of the stress σ 2 (N/tex) at 5% elongation of the band cord and the complex elastic modulus E* 1 (MPa) is 0.40 to 1.60 (N·MPa/tex).

14. The pneumatic tire according to claim 13 , wherein
a sea ratio of the ground contacting surface of the tread portion is 15% to 50%, and
a product of the complex elastic modulus E* 1 (MPa) and the sea ratio (%) of the ground contacting surface of the tread portion is not more than 5.0 (MPa).

15. The pneumatic tire according to claim 11 , wherein
a sea ratio of the ground contacting surface of the tread portion is 15% to 50%, and
a ratio t 1 /d 1 (%) between the thickness t 1 and the distance d 1 is smaller than the sea ratio (%).

16. The pneumatic tire according to claim 15 , wherein a ratio σ 1 /σ 2 (%) of the stress σ 1 (N/tex) at 3% elongation of the band cord to the stress σ 2 (N/tex) at 5% elongation of the band cord is greater than the sea ratio (%) of the ground contacting surface of the tread portion.

17. The pneumatic tire according to claim 15 , wherein
the tread rubber includes a rubber compound having a complex elastic modulus E* 1 of not more than 10 (MPa) at 30 degrees C.,
a product d 1 ·E* 1 of the distance d 1 (mm) and the complex elastic modulus E* 1 (MPa) is 5.0 to 30.0 (MPa·mm), and
a product σ 2 ·E* 1 of the stress σ 2 (N/tex) at 5% elongation of the band cord and the complex elastic modulus E* 1 (MPa) is 0.40 to 1.60 (N·MPa/tex).

18. The pneumatic tire according to claim 17 , wherein
a sea ratio of the ground contacting surface of the tread portion is 15% to 50%, and
a product of the complex elastic modulus E* 1 (MPa) and the sea ratio (%) of the ground contacting surface of the tread portion is not more than 5.0 (MPa).

19. The pneumatic tire according to claim 17 , wherein
a sea ratio of the ground contacting surface of the tread portion is 15% to 50%, and
a ratio σ 1 /σ 2 (%) of the stress σ 1 (N/tex) at 3% elongation of the band cord to the stress σ 2 (N/tex) at 5% elongation of the band cord is greater than the sea ratio (%) of the ground contacting surface of the tread portion.

Assignees

• Sumitomo Rubber Ind

Inventors

• MISEKI Yuta

Classifications

• B60C2009/2238

  Physical properties or dimensions of the ply coating rubber · CPC title

• B60C2009/2214

  characterised by the materials of the zero degree ply cords · CPC title

• B60C2009/2252

  Physical properties or dimension of the zero degree ply cords · CPC title

• B60C2009/2276

  Tensile strength · CPC title

• B60C2011/0025

  Modulus or tan delta · CPC title