PNEUMATIC TIRE

• US 20120160382A1
• Filed: 12/14/2011
• Published: 06/28/2012
• Est. Priority Date: 12/27/2010
• Status: Active Grant

• Current Assignee: Yokohama Rubber Company Limited
• Original Assignee: Yokohama Rubber Company Limited
• Inventors: Okabe, Hidetoshi
• Granted Patent: US 8,875,756 B2
• Time in Patent Office: Days
• US Class Current: 152/209.15
• CPC Class Codes: B60C 11/01 Shape of the shoulders between tread and sidewall, e.g. rounded, stepped or cantilevered
• CPC Class Codes: B60C 11/04 in which the raised area of the pattern consists only of continuous circumferential ribs, e.g. zig-zag B60C11/12, B60C11/13 take precedence
• CPC Class Codes: B60C 2011/013 provided with a recessed portion
• CPC Class Codes: B60C 2011/0348 Narrow grooves, i.e. having a width of less than 4 mm
• CPC Class Codes: B60C 2011/0355 characterised by depth

Abstract

A pneumatic tire including a plurality of circumferential main grooves extending in a tire circumferential direction, a plurality of land portions partitioned by the circumferential main grooves, a narrow groove extending in the tire circumferential direction and disposed in an edge portion of a road contact surface side and an outer side in the tire width direction of the shoulder land portion on an outermost side in a tire width direction, and a narrow rib that is partitioned by the narrow groove. The narrow rib includes an offset portion having a road contact surface offset inward in a tire radial direction from the road contact surface of the shoulder land portion, and a protrusion protruding in the tire radial direction from the offset portion, extending in the tire circumferential direction, and having a top surface that is substantially flush with a profile line of the shoulder land portion.

Claims

1. A pneumatic tire comprising:

a plurality of circumferential main grooves extending in a tire circumferential direction,

a plurality of land portions partitioned by the circumferential main grooves,

a narrow groove extending in the tire circumferential direction and disposed in an edge portion of a road contact surface side and an outer side in the tire width direction of a shoulder land portion on an outermost side in a tire width direction, and

a narrow rib that is partitioned by the narrow groove;

wherein

the narrow rib includes;

an offset portion having a road contact surface offset inward in a tire radial direction from the road contact surface of the shoulder land portion, and

a protrusion protruding in the tire radial direction from the offset portion, extending in the tire circumferential direction, and having a top surface that is substantially flush with a profile line of the shoulder land portion.

2. The pneumatic tire according to claim 1, wherein a width W2 of the narrow rib and a width W1 of the road contact surface of the shoulder land portion have a relationship such that 0.20≦

W2/W1≦

0.40.

3. The pneumatic tire according to claim 1, wherein a width W3 of the top surface of the protrusion and a width W2 of the narrow rib have a relationship such that 0.10≦

W3/W2≦

0.40.

4. The pneumatic tire according to claim 1, wherein a distance δ

between the top surface of the protrusion and the road contact surface of the shoulder land portion is within a range of −

0.5 mm≦

δ

≦

0.5 mm.

5. The pneumatic tire according to claim 1, wherein an offset amount g between the road contact surface of the offset portion and the road contact surface of the shoulder land portion is within a range of 0.5 mm≦

g≦

3.0 mm.

6. The pneumatic tire according to claim 1, wherein a groove width d of the narrow groove is within a range of 0.1 mm≦

d≦

4.0 mm; and

a groove depth h of the narrow groove, with respect to a groove depth H of the circumferential main groove partitioning the shoulder land portion, is within a range of 0.80≦

h/H≦

1.10.

7. The pneumatic tire according to claim 1, wherein a width W4 of a portion of the road contact surface of the offset portion that is substantially parallel to the profile of the shoulder land portion has a relationship with respect to a width W2 of the narrow rib such that 0.1≦

W4/W2≦

0.7.

8. The pneumatic tire according to claim 7, wherein the width W4 is within a range of 5 mm≦

W4≦

11 mm.

9. The pneumatic tire according to claim 1, wherein a width W3 of the top surface of the protrusion is configured to be within a range of 1 mm≦

W3≦

3 mm.

10. The pneumatic tire according to claim 1, wherein a width W2 of the narrow rib is configured to be within a range of 8 mm≦

W2≦

12 mm.

11. The pneumatic tire according to claim 1, wherein the top surface of the protrusion has a planar form.

12. The pneumatic tire according to claim 1, wherein when viewed as a cross-section in the tire meridian direction, the protrusion has a semicircular cross-section.

13. The pneumatic tire according to claim 1, wherein when viewed as a cross-section in the tire meridian direction, the protrusion has an arc shaped top surface.

14. The pneumatic tire according to claim 1, wherein:

a width W2 of the narrow rib and a width W1 of the road contact surface of the shoulder land portion have a relationship such that 0.20≦

W2/W1≦

0.40;

a width W3 of the top surface of the protrusion and a width W2 of the narrow rib have a relationship such that 0.10≦

W3/W2≦

0.40; and

a width W4 of a portion of the road contact surface of the offset portion that is substantially parallel to the profile of the shoulder land portion has a relationship with respect to a width W2 of the narrow rib such that 0.1≦

W4/W2≦

0.7.

15. The pneumatic tire according to claim 14, wherein:

the width W2 of the narrow rib is within a range of 8 mm≦

W2≦

12 mm;

the width W3 of the top surface of the protrusion is within a range of 1 mm≦

W3≦

3 mm; and

the width W4 is within a range of 5 mm≦

W4≦

11 mm.

16. The pneumatic tire according to claim 1, wherein a width W4 of a portion of the road contact surface of the offset portion that is substantially parallel to the profile of the shoulder land portion has a relationship with respect to a width W2 of the narrow rib such that 0.47≦

W4/W2≦

0.7.

17. The pneumatic tire according to claim 1, wherein a width W3 of the top surface of the protrusion and a width W2 of the narrow rib have a relationship such that 0.17≦

W3/W2≦

0.25.

18. The pneumatic tire according to claim 2, wherein a width W3 of the top surface of the protrusion and a width W2 of the narrow rib have a relationship such that 0.10≦

W3/W2≦

0.40.

19. The pneumatic tire according to claim 18, wherein a distance δ

between the top surface of the protrusion and the road contact surface of the shoulder land portion is within a range of −

0.5 mm≦

δ

≦

0.5 mm.

20. The pneumatic tire according to claim 19, wherein an offset amount g between the road contact surface of the offset portion and the road contact surface of the shoulder land portion is within a range of 0.5 mm≦

g≦

3.0 mm.