Pneumatic Tire

• US 20150075686A1
• Filed: 03/19/2013
• Published: 03/19/2015
• Est. Priority Date: 03/21/2012
• Status: Active Grant

• Current Assignee: Yokohama Rubber Company Limited
• Original Assignee: Yokohama Rubber Company Limited
• Inventors: Suga, Yuuichi
• Granted Patent: US 9,216,618 B2
• Time in Patent Office: Days
• US Class Current: 152/209.16
• CPC Class Codes: B60C 11/01 Shape of the shoulders between tread and sidewall, e.g. rounded, stepped or cantilevered
• CPC Class Codes: B60C 11/0304 Asymmetric patterns
• CPC Class Codes: B60C 11/033 by the void or net-to-gross ratios of the patterns
• 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 11/12 characterised by the use of narrow slits or incisions, e.g. sipes
• CPC Class Codes: B60C 11/1323 asymmetric
• CPC Class Codes: B60C 11/1392 with chamfered block edges
• CPC Class Codes: B60C 2011/0341 Circumferential grooves
• CPC Class Codes: B60C 2011/0348 Narrow grooves, i.e. having a width of less than 4 mm
• CPC Class Codes: B60C 2011/0353 characterised by width
• CPC Class Codes: B60C 2011/0365 characterised by width
• CPC Class Codes: B60C 2011/0367 characterised by depth
• CPC Class Codes: B60C 2011/0381 Blind or isolated grooves
• CPC Class Codes: B60C 2011/0388 provided at the equatorial plane

Abstract

A pneumatic tire is mounted on a vehicle so a first side in a tire width direction corresponds to a vehicle outer side. A tread surface has four circumferential main grooves extending in a tire circumferential direction and five land portions partitioned by the circumferential main grooves. A ratio W₂/W₁ ranges 4 to 5 when W₁ is a groove width of a first circumferential main groove that is located at a first position when viewed from the first side and W₂ is defined as a groove width of a second circumferential main groove located at a second position when viewed from the first side, and a ratio S_in/S_out ranges 1.1 to 1.2 when, in a region of the tread surface which interposes the tire centerline, S_out is defined as a groove surface area ratio in a region on the first side and S_in is defined as a groove surface area ratio in a region on the second side.

Claims

1. A pneumatic tire that mounts on a vehicle so that, when the pneumatic tire is mounted, a first side in a tire width direction corresponds to a vehicle outer side and a second side that is an opposite side of the first side in the tire width direction corresponds to a vehicle inner side, wherein

a region of a tread surface of the pneumatic tire includes:

four circumferential main grooves extending in a tire circumferential direction;

five land portions partitioned by the circumferential main grooves;

first shoulder inclined grooves that are formed in a region of a first side shoulder land portion, from among the land portions, positioned on an outermost side in the tire width direction on the first side and extend in the tire width direction;

second side shoulder inclined grooves that are formed in a region of a second side shoulder land portion positioned on an outermost side in the tire width direction on the second side and extend in the tire width direction; and

chamfers formed on an entire periphery of an edge where the first side shoulder land portion contacts the first shoulder inclined grooves and an entire periphery of an edge where the second side shoulder land portion contacts the second side shoulder inclined grooves;

a ratio W₂/W₁ that represents a ratio of a groove width W₂ of a second circumferential main groove located at a second position when viewed from the first side to a groove width W₁ of a first circumferential main groove located at a first position when viewed from the first side from among the four circumferential main grooves ranges from 4 to 5 when W₂ is in a range of 16 to 20 mm; and

a ratio S_in/S_out that represents a ratio of a groove surface area ratio S_in in a region located on the second side when viewed from a tire centerline to a groove surface area ratio S_out in a region located on the first side when viewed from the tire centerline in the region of the tread surface ranges from 1.1 to 1.2 when S_in is in a range of 35.2 to 38.4%.

2. The pneumatic tire according to claim 1, wherein the first shoulder inclined grooves connect to the first circumferential main groove, and the second shoulder inclined grooves extend from the second side toward the first side and are blocked in a region of the second side shoulder land portion without connecting to a fourth circumferential main groove located at a fourth position when viewed from the first side from among the four circumferential main grooves.

3. The pneumatic tire according to claim 1, wherein the tire centerline passes through between the second circumferential main groove and a third circumferential main groove located at a third position when viewed from the first side from among the four circumferential main grooves,

a continuous land portion extends continuously so as to go completely around in the tire circumferential direction is formed between the second circumferential main groove and the third circumferential main groove, and

center inclined grooves that extends from the third circumferential main groove toward the first side and are blocked midway without reaching the tire centerline are provided in a region of the continuous land portion.

4. The pneumatic tire according to claim 1, wherein both an intermediate land portion formed between the first circumferential main groove and the second circumferential main groove and an intermediate land portion formed between a third circumferential main groove located at a third position when viewed from the first side from among the four circumferential main grooves and a fourth circumferential main groove located at a fourth position when viewed from the first side from among the four circumferential main grooves are continuous land portions that extend continuously so as to go completely around in the tire circumferential direction.

5. The pneumatic tire according to claim 1, wherein chamfer surfaces of the chamfers are flat surfaces or curved surfaces.

6. The pneumatic tire according to claim 1, wherein the chamfers are flat surfaces, and

a depth and a width at which the chamfers are applied is 0.5 to 2 mm.

7. The pneumatic tire according to claim 1, wherein an average groove interval of the first shoulder inclined grooves is longer compared to an average groove interval of the second shoulder inclined grooves.

8. The pneumatic tire according to claim 1, wherein a ratio W₄/W₃ that represents a ratio of a groove width W₄ of a fourth circumferential main groove located at a fourth position when viewed from the first side to a groove width W₃ of a third circumferential main groove located at a third position when viewed from the first side ranges from 0.95 to 1.0.

9. The pneumatic tire according to claim 1, wherein a ratio D₁/D₂ that represents a ratio of a groove depth D₁ of the first circumferential main groove to a groove depth D₂ of the second circumferential main groove from among the four circumferential main grooves and a ratio D₄/D₃ that represents a ratio of a groove depth D₄ of a fourth circumferential main groove located at a fourth position when viewed from the first side to a ratio D₃ of a third circumferential main groove located at a third position when viewed from the first side from among the four circumferential grooves are both less than 1.

10. The pneumatic tire according to claim 1, wherein, in regions of land portions located at a second, a third, and a fourth position when viewed from the first side from among the five land portions, a plurality of inclined grooves that extend in a direction inclined relative to the tire width direction from an edge positioned on the second side and are blocked midway are provided along the tire circumferential direction, and a second land portion located at the second position is longer compared to a fourth land portion located at the fourth position in regard to average groove intervals thereof.

11. The pneumatic tire according to claim 10, wherein the average groove interval of the inclined grooves provided in the region of the second land portion is 1.15 to 1.25 times the average groove interval of the inclined grooves provided in the region of the fourth land portion.

12. The pneumatic tire according to claim 10, wherein inclined grooves extending in the regions of a third land portion located at the third position and a fourth land portion located at the fourth position have no opening end at edges on the first side thereof.

13. The pneumatic tire according to claim 2, wherein the tire centerline passes through between the second circumferential main groove and a third circumferential main groove located at a third position when viewed from the first side from among the four circumferential main grooves,

a continuous land portion extends continuously so as to go completely around in the tire circumferential direction is formed between the second circumferential main groove and the third circumferential main groove, and

center inclined grooves that extends from the third circumferential main groove toward the first side and are blocked midway without reaching the tire centerline are provided in a region of the continuous land portion.

14. The pneumatic tire according to claim 13, wherein both an intermediate land portion formed between the first circumferential main groove and the second circumferential main groove and an intermediate land portion formed between a third circumferential main groove located at a third position when viewed from the first side from among the four circumferential main grooves and a fourth circumferential main groove located at a fourth position when viewed from the first side from among the four circumferential main grooves are continuous land portions that extend continuously so as to go completely around in the tire circumferential direction.

15. The pneumatic tire according to claim 14, wherein chamfer surfaces of the chamfers are flat surfaces or curved surfaces.

16. The pneumatic tire according to claim 14, wherein the chamfers are flat surfaces, and

a depth and a width at which the chamfers are applied is 0.5 to 2 mm.

17. The pneumatic tire according to claim 16, wherein an average groove interval of the first shoulder inclined grooves is longer compared to an average groove interval of the second shoulder inclined grooves.

18. The pneumatic tire according to claim 17, wherein a ratio W₄/W₃ that represents a ratio of a groove width W₄ of the fourth circumferential main groove located at a fourth position when viewed from the first side to a groove width W₃ of a third circumferential main groove located at a third position when viewed from the first side ranges from 0.95 to 1.0.

19. The pneumatic tire according to claim 4, wherein a ratio D₁/D₂ that represents a ratio of a groove depth D₁ of the first circumferential main groove to a groove depth D₂ of the second circumferential main groove from among the four circumferential main grooves and a ratio D₄/D₃ that represents a ratio of a groove depth D₄ of a fourth circumferential main groove located at a fourth position when viewed from the first side to a ratio D₃ of a third circumferential main groove located at a third position when viewed from the first side from among the four circumferential grooves are both less than 1.

20. The pneumatic tire according to claim 19, wherein, in regions of land portions located at a second, a third, and a fourth position when viewed from the first side from among the five land portions, a plurality of inclined grooves that extend in a direction inclined relative to the tire width direction from an edge positioned on the second side and are blocked midway are provided along the tire circumferential direction, and

a second land portion located at the second position is longer compared to a fourth land portion located at the fourth position in regard to average groove intervals thereof.