PNEUMATIC TIRE

• US 20090320982A1
• Filed: 07/17/2007
• Published: 12/31/2009
• Est. Priority Date: 08/03/2006
• Status: Active Grant

• Current Assignee: Bridgestone Corporation
• Original Assignee: Bridgestone Corporation
• Inventors: Ochi, Naoya
• Granted Patent: US 8,708,009 B2
• Time in Patent Office: Days
• US Class Current: 152/209.25
• CPC Class Codes: B60C 11/0306 Patterns comprising block rows or discontinuous ribs
• CPC Class Codes: B60C 11/13 characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping
• CPC Class Codes: B60C 11/1384 with chamfered block corners
• CPC Class Codes: B60C 11/1392 with chamfered block edges
• CPC Class Codes: B60C 2011/0374 Slant grooves, i.e. having an angle of about 5 to 35 degrees to the equatorial plane
• CPC Class Codes: B60C 2011/133 comprising recesses
• CPC Class Codes: B60C 2200/14 for off-road use

Abstract

To enhance cornering performance on each road surface and improve steering stability while ensuring traction performance and breaking performance of a pneumatic tire on a snow road or off-road.

A shoulder land row (31) between a main groove (11) extending in the tire peripheral direction of a tread unit (2) and a tread end (TE) is partitioned into plan-view trapezoidal blocks (31B) with their widths reducing toward the outer side of a tire width direction by shoulder lug grooves (26) in an almost tire width direction. A plan-view trapezoidal notch (40) with its width reducing toward the inside of a block (31B) is formed in almost the center of the main groove (11) side edge of a block (31B), and an inclined surface (41) extending from the surface of the block (31B) toward the bottom of the main groove (11) is formed in the notch (40) integrally with the block (31B). This inclined surface (41) is formed stepwise by a plurality of recessed curved surfaces and protruding ridges formed between them.

Claims

1. A pneumatic tire comprising:

a plurality of land rows formed with a plurality of main grooves extending in a tire peripheral direction, in a tread unit thereof, the land rows being partitioned into a plurality of blocks by a plurality of lug grooves extending in the intersecting direction with the main grooves, wherein

a block in at least one of the land rows has a notch cut into the block from an edge portion thereof, and

the notch has an inclined surface therein formed with a step portion extending in a groove bottom direction on a side of the edge portion of the block from a surface inside the block.

2. The pneumatic tire according to claim 1, wherein

the step portion of the inclined surface is formed in a stairstep shape constituted by a plurality of recessed curved surfaces and protruding ridges provided between the recessed curved surfaces.

3. The pneumatic tire according to claim 2, wherein

the protruding ridge is constituted by an upper surface which is parallel in tire width direction and a side surface which is parallel in tire radial direction, and an angle of top end side of the protruding ridge is formed to be 80 degrees to 120 degrees.

4. The pneumatic tire according to claim 2, wherein

the inclined surface includes at least two protruding ridges.

5. The pneumatic tire according to claim 1, wherein,

a shoulder land row disposed between a tread end of the tread unit and the outside-most main groove in the tire width direction has the block having a plan-view trapezoidal shape, width of which is gradually reduced from the main groove side toward the tread end side;

and

a main groove side edge portion of the trapezoidal shape block has the notch.

6. The pneumatic tire according to claim 1, wherein

the notch is formed to be a plan-view trapezoidal shape, width of which is gradually reduced from edge of the block toward inside of the block.

7. The pneumatic tire according to claim 3, wherein

the inclined surface includes at least two protruding ridges.

8. The pneumatic tire according to claim 2, wherein,

a shoulder land row disposed between a tread end of the tread unit and the outside-most main groove in the tire width direction has the block having a plan-view trapezoidal shape, width of which is gradually reduced from the main groove side toward the tread end side;

and

a main groove side edge portion of the trapezoidal shape block has the notch.

9. The pneumatic tire according to claim 3, wherein,

a shoulder land row disposed between a tread end of the tread unit and the outside-most main groove in the tire width direction has the block having a plan-view trapezoidal shape, width of which is gradually reduced from the main groove side toward the tread end side;

and

a main groove side edge portion of the trapezoidal shape block has the notch.

10. The pneumatic tire according to claim 4, wherein,

a shoulder land row disposed between a tread end of the tread unit and the outside-most main groove in the tire width direction has the block having a plan-view trapezoidal shape, width of which is gradually reduced from the main groove side toward the tread end side;

and

a main groove side edge portion of the trapezoidal shape block has the notch.

11. The pneumatic tire according to claim 2, wherein

the notch is formed to be a plan-view trapezoidal shape, width of which is gradually reduced from edge of the block toward inside of the block.

12. The pneumatic tire according to claim 3, wherein

the notch is formed to be a plan-view trapezoidal shape, width of which is gradually reduced from edge of the block toward inside of the block.

13. The pneumatic tire according to claim 4, wherein

the notch is formed to be a plan-view trapezoidal shape, width of which is gradually reduced from edge of the block toward inside of the block.

14. The pneumatic tire according to claim 5, wherein

the notch is formed to be a plan-view trapezoidal shape, width of which is gradually reduced from edge of the block toward inside of the block.