Pneumatic tire

Patent metadata

Field	Value
Publication number	US-10369845-B2
Application number	US-201214434357-A
Country	US
Kind code	B2
Filing date	Oct 10, 2012
Priority date	Oct 10, 2012
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

Abstract

A pneumatic tire is provided with a carcass layer, a belt layer disposed on the outer side of the carcass layer in a radial direction of the tire, and tread rubber disposed on the outer side of the belt layer in the radial direction of the tire. The belt layer is formed by layering a pair of cross belts having belt angles with absolute values from 10° to 45° inclusive and opposite signs, and a circumferential reinforcing layer having a belt angle within a range of ±5° with respect to the circumferential direction of the tire. A distance (Gcc) from a tread profile to an inner circumferential surface of the tire along a tire equatorial plane and a distance (Gsh) from a tread end (p) to the inner circumferential surface of the tire have a relationship such that 1.10≤Gsh/Gcc.

First claim

The invention claimed is:

1. A pneumatic tire comprising: a carcass layer; a belt layer disposed on an outer side in a radial direction of the tire of the carcass layer; a tread rubber disposed on an outer side in the radial direction of the tire of the belt layer; at least three circumferential main grooves extending in a circumferential direction of the tire; and a plurality of land portions defined by the circumferential main grooves;
the belt layer being formed by layering a pair of cross belts having belt angles with absolute values of 10° to 45° inclusive and opposite signs, and a circumferential reinforcing layer having a belt angle within a range of ±5° with respect to the circumferential direction of the tire, the circumferential reinforcing layer being configured by belt cords formed from steel;
a distance Gcc from a tread profile to an inner circumferential surface of the tire along a tire equatorial plane and a distance Gsh from a tread edge to an inner circumferential surface of the tire having a relationship such that 1.25≤Gsh/Gcc;
defining an intersection between a vertical line drawn from the tread edge to the inner circumferential surface of the tire and a wider cross belt of the pair of cross belts as point Q 1 and a base of a vertical line drawn from an outer end of the circumferential reinforcing layer with respect to a widthwise direction of the tire to the wider cross belt as point Q 2 , a distance Gs from point Q 1 to the tread profile and a distance Ge from point Q 2 to the tread profile having a relationship such that 1.00≤Gs/Ge;
defining point Q 3 as an intersection between a groove centerline of a circumferential main groove nearest the tire equatorial plane and a belt ply out of steel cord belt plies constituting the belt layer that is located furthest outward in the radial direction of the tire as seen in a longitudinal cross-sectional view of the tire, a groove depth Dc of the circumferential main groove nearest the tire equatorial plane and a distance Tc from the point Q 3 to the tread profile have a relationship such that 1.30≤Tc/Dc≤1.55; and
defining point Q 4 as an intersection between a vertical line drawn from an end portion of the circumferential reinforcing layer to the tread profile and a belt ply out of belt plies made of steel cord constituting the belt layer on an outermost side in the radial direction of the tire when viewed as a cross-section from a longitudinal direction of the tire, a groove depth De of the circumferential main groove on an outermost side in the widthwise direction of the tire and a distance Te from point Q 4 to the tread profile have a relationship such that 1.35≤Te/De≤1.60;
wherein the pneumatic tire is a heavy duty tire with an aspect ratio of 70% or less.

2. The pneumatic tire according to claim 1 , wherein a tread width TW and a width Ws of the circumferential reinforcing layer have a relationship such that 0.70≤Ws/TW≤0.90.

3. The pneumatic tire according to claim 1 , wherein a width Wb 2 of the wider cross belt of the pair of cross belts and a width Wca of the carcass layer have a relationship such that 0.74≤Wb 2 /Wca≤0.89.

4. The pneumatic tire according to claim 1 , wherein belt cords of the cross belts are steel wires, and have at least 18 ends per 50 mm and no more than 28 ends per 50 mm.

5. The pneumatic tire according to claim 1 , wherein the belt layer has a large angle belt having a belt angle with an absolute value of 45° to 70° inclusive.

6. The pneumatic tire according to claim 5 , wherein belt cords of the large angle belt are steel wires, and have at least 15 ends per 50 mm and no more than 25 ends per 50 mm.

7. The pneumatic tire according to claim 5 , wherein a width Wb 1 of the large angle belt and a width Wb 3 of a narrower cross belt of the pair of cross belts have a relationship such that 0.85≤Wb 1 /Wb 3 ≤1.05.

8. The pneumatic tire according to claim 1 , wherein the tread rubber has a hardness of 70 or less.

9. The pneumatic tire according to claim 1 , wherein belt cords of the circumferential reinforcing layer are steel wires, and have at least 17 ends per 50 mm and not more than 30 ends per 50 mm.

10. The pneumatic tire according to claim 1 , wherein elongation is from 1.0% to 2.5% inclusive when a tensile load of belt cords as components that configure the circumferential reinforcing layer is from 100 N to 300 N.

11. The pneumatic tire according to claim 1 , wherein elongation is from 0.5% to 2.0% inclusive when a tensile load of belt cords as cured tire components that constitute the circumferential reinforcing layer is from 500 N to 1000 N.

12. The pneumatic tire according to claim 1 , wherein the circumferential reinforcing layer is disposed further inward with respect to a tire widthwise direction than right and left edge portions of the narrower of the pair of cross belts, and the tire is provided with:
stress relief rubber disposed between the pair of cross belts and disposed to the outer side of the circumferential reinforcing layer with respect to the widthwise direction of the tire so as to be adjacent to the circumferential reinforcing layer; and
end portion relief rubber disposed between the pair of cross belts and disposed to the outer side of the stress relief rubber with respect to the widthwise direction of the tire at a position corresponding to edge portions of the pair of cross belts so as to be adjacent to the stress relief rubber.

13. The pneumatic tire according to claim 12 , wherein a modulus Ein at 100% elongation of the stress relief rubber and a modulus Eco at 100% elongation of coating rubber of the pair of cross belts have a relationship such that Ein<Eco.

14. The pneumatic tire according to claim 12 , wherein the modulus Ein at 100% elongation of the stress relief rubber and the modulus Eco at 100% elongation of coating rubber of the pair of cross belts have a relationship such that 0.6≤Ein/Eco≤0.9.

15. The pneumatic tire according to claim 12 , wherein the modulus Ein at 100% elongation of the stress relief rubber is in a range of 4.0 MPa≤Ein≤5.5 MPa.

16. The pneumatic tire according to claim 1 , wherein the circumferential reinforcing layer is disposed further inward with respect to a tire widthwise direction than right and left edge portions of a narrower cross belt of the pair of cross belts; and
a width Wb 3 of the narrower cross belt and a distance S from an edge portion of the circumferential reinforcing layer to an edge portion of the narrower cross belt are in a range of 0.03≤S/Wb 3 .

17. The pneumatic tire according to claim 1 , wherein 1.50≤Te/De≤1.60.

18. The pneumatic tire according to claim 1 , wherein a difference between the relationships Te/De and Tc/Dc is 0.05 or more.

19. The pneumatic tire according to claim 1 , wherein 1.45≤Tc/Dc≤1.55 and 1.50≤Te/De≤1.60.

20. The pneumatic tire according to claim 1 , wherein a tread width TW and a width Ws of the circumferential reinforcing layer have a relationship such that 0.70≤Ws/TW≤0.90, and the outer end of the circumferential reinforcing layer is located inside the circumferential main groove on the outermost side in the widthwise direction of the tire.

Assignees

• Yokohama Rubber Co Ltd

Inventors

• Nagayoshi Masatoshi

Classifications

• B60C2011/0025

  Modulus or tan delta · CPC title

• B60C9/2006

  consisting of steel cord plies only · CPC title

• B60C2011/0355

  characterised by depth · CPC title

• B60C2011/0016

  Physical properties or dimensions · CPC title

• B60C2009/2261

  Modulus of the cords · CPC title