TIRE

• US 20130000804A1
• Filed: 02/18/2011
• Published: 01/03/2013
• Est. Priority Date: 02/18/2010
• Status: Active Grant

• Current Assignee: Bridgestone Corporation
• Original Assignee: Bridgestone Corporation
• Inventors: Kiwaki, Yukihiro
• Granted Patent: US 9,221,304 B2
• Time in Patent Office: Days
• US Class Current: 152/209.1
• CPC Class Codes: B60C 11/0302 directional pattern, i.e. with main rolling direction
• CPC Class Codes: B60C 11/0306 Patterns comprising block rows or discontinuous ribs
• CPC Class Codes: B60C 11/0309 further characterised by the groove cross-section
• CPC Class Codes: B60C 11/125 arranged at the groove bottom
• CPC Class Codes: B60C 11/1353 with special features of the groove bottom
• CPC Class Codes: B60C 2011/0341 Circumferential grooves
• CPC Class Codes: B60C 2011/0344 provided at the equatorial plane
• CPC Class Codes: B60C 2011/0348 Narrow grooves, i.e. having a width of less than 4 mm
• CPC Class Codes: B60C 2011/0351 Shallow grooves, i.e. having a depth of less than 50% of other grooves
• CPC Class Codes: B60C 2011/0381 Blind or isolated grooves
• CPC Class Codes: B60C 2011/1254 with closed sipe, i.e. not extending to a groove
• CPC Class Codes: B60C 2011/133 comprising recesses

Abstract

An intra-groove groove 310,330 is formed in circumferential groove 31,33 which is formed in a pneumatic tire 1, the intra-groove groove 310,330 is recessed farther inward in a tire radial direction TR than the circumferential groove 31,33. The intra-groove groove 310,330 includes a high-angle groove section 311,331 in which an angle θ1 formed between a straight line L1 and the intra-groove groove 310,330 is equal to or more than a predetermined angle, and a low-angle groove section 312,332 in which an angle θ2 formed between the straight line L1 and the intra-groove groove 310,330 is smaller than the predetermined angle. The high-angle groove section 311,331 is positioned closer to an intra-groove center line DCL than the low-angle groove section 312,332. A width W1 of the high-angle groove section 311, 331 is wider than a width W2 of the low-angle groove section 312, 332.

Claims

1. A tire comprising:

a plurality of rib-shaped land portions which extend in a tire circumferential direction; and

a circumferential groove positioned between the land portions and extending in the tire circumferential direction, wherein

the circumferential groove is formed with an intra-groove groove recessed farther inward in a tire radial direction than the circumferential groove with a groove bottom of the circumferential groove being an upper end of the intra-groove groove, the intra-groove groove includes;

a high-angle groove section in which an angle formed between a straight line perpendicular to a tire equator line and the intra-groove groove is equal to or more than a predetermined angle, and

a low-angle groove section in which an. angle formed between the straight line and the intra-groove groove is smaller than the predetermined angle, and which is continuous with the high-angle groove section,

the high-angle groove section is positioned closer, than the low-angle groove section, to an intra-groove center line passing through a center of a tread width direction of the circumferential groove, and

a width perpendicular to an extension direction of the

high-angle groove section is wider than a width perpendicular to an extension direction of the low-angle groove section.

2. The tire according to claim 1, wherein

the high-angle groove section extends along the tire circumferential direction, and

the low-angle groove section extends along a tread width direction.

3. The tire according to claim 1, wherein each of the low-angle groove sections is provided at both ends of the high-angle groove section.

4. The tire according to claim 1, wherein the low-angle groove section is connected to the land portion.

5. The tire according to claim 1, wherein

the land portion includes an outer land portion positioned outward in the tread width direction of the circumferential groove, and

the outer land portion is formed with a small hole recessed farther inward in the tire radial direction than a tread contact surface.

6. The tire according to claim 5, wherein. the small hole is positioned between low-angle groove sections adjacent to each other in the tire circumferential direction.