Pneumatic tire

• US 9,346,323 B2
• Filed: 01/30/2013
• Issued: 05/24/2016
• Est. Priority Date: 02/02/2012
• Status: Active Grant

• Current Assignee: Yokohama Rubber Company Limited
• Original Assignee: Yokohama Rubber Company Limited
• Inventors: Sakamoto, Yousuke
• Primary Examiner(s): Hug, Eric
• Application Number:
  US13/754,271
• Publication Number:
  US 20130199684A1
• Time in Patent Office: 1,210 Days
• Field of Search: 152/209.3, 152/209.8, 152/209.9, 152/209.18, 152/209.26, 152/209.27, 152/900, 152/901
• US Class Current: 1/1
• CPC Class Codes: B60C 11/0304 Asymmetric patterns
• CPC Class Codes: B60C 11/0306 Patterns comprising block rows or discontinuous ribs
• CPC Class Codes: B60C 11/0311 Patterns comprising tread lugs arranged parallel or oblique to the axis of rotation
• CPC Class Codes: B60C 11/1369 Tie bars for linking block elements and bridging the groove
• CPC Class Codes: B60C 11/1392 with chamfered block edges
• CPC Class Codes: B60C 2011/0358 Lateral grooves, i.e. having an angle of 45 to 90 degees to the equatorial plane
• CPC Class Codes: B60C 2011/0365 characterised by width
• CPC Class Codes: B60C 2011/0383 at the centre of the tread
• CPC Class Codes: B60C 2011/0388 provided at the equatorial plane

Abstract

A circumferential narrow groove of a pneumatic tire is disposed at a position that partitions an outer side second land portion and an outer side shoulder land portion. A center land portion is a rib that is continuous in a tire circumferential direction, and an inner side second land portion and the outer side second land portion are rows of blocks divided in the tire circumferential direction by pluralities of lug grooves. Additionally, a groove area ratio S2 of the center land portion, a groove area ratio S1 of the inner side second land portion, and a groove area ratio S3 of the outer side second land portion have a relationship such that S2<S3<S1. Moreover, a groove width Wd of the circumferential narrow groove and a maximum groove width Wmax of the other three circumferential main grooves to have a relationship such that 3.1≦Wmax/Wd≦5.0.

Claims

1. A pneumatic tire comprising:

three circumferential main grooves;

one circumferential narrow groove having a groove width that is less than that of the circumferential main grooves; and

one row of center land portion, a pair of left and right second land portions, and a pair of left and right shoulder land portions partitioned and formed by the circumferential main grooves and the circumferential narrow groove in a tread portion, wherein

when the second land portion and the shoulder land portion in a first region demarcated by the center land portion are referred to as an inner side second land portion and an inner side shoulder land portion, and the second land portion and the shoulder land portion in a second region are referred to as an outer side second land portion and an outer side shoulder land portion,

the circumferential narrow groove is disposed at a position that partitions the outer side second land portion and the outer side shoulder land portion,

the center land portion is a rib that is continuous in a tire circumferential direction, the inner side second land portion and the outer side second land portion are rows of blocks divided in the tire circumferential direction by a plurality of lug grooves,

a groove area ratio S2 of the center land portion, a groove area ratio S1 of the inner side second land portion, and a groove area ratio S3 of the outer side second land portion have a relationship such that S2<

S3<

S1, 1.05≦

S3/S2 and 1.05≦

S1/S3, and

a groove width Wd of the circumferential narrow groove and a maximum groove width Wmax of the other three circumferential main grooves have a relationship such that 3.1≦

Wmax/Wd≦

5.0.

2. The pneumatic tire according to claim 1, wherein

the inner side second land portion comprises a first lug groove penetrating the inner side second land portion and a second lug groove that is open to an edge portion on the inner side shoulder land portion side of the inner side second land portion and that terminates within the inner side second land portion,

a plurality of the first lug grooves and a plurality of the second lug grooves are disposed so as to co-exist at a predetermined spacing in the tire circumferential direction, and

the first lug grooves comprise raised bottom portions in a region from an edge portion on the center land portion side of the inner side second land portion to a predetermined position within the inner side second land portion.

3. The pneumatic tire according to claim 2, wherein a distance D1 in a tire width direction of the disposal region of the raised bottom portions and a width W1 of the inner side second land portion have a relationship such that 0.30≦

D1/W1≦

0.70.

4. The pneumatic tire according to claim 2, wherein the inner side second land portion comprises sipes connecting the second lug grooves and the edge portion on the center land portion side of the inner side second land portion.

5. The pneumatic tire according to claim 2, wherein a length D2 in the tire width direction of the second lug grooves and the width W1 of the inner side second land portion have a relationship such that 0.40≦

D2/W1≦

0.60.

6. The pneumatic tire according to claim 2, wherein the center land portion comprises lug grooves that are open to the edge portion on the inner side second land portion side and that terminate within the center land portion, and said lug grooves are positioned substantially on extended lines of the second lug grooves of the inner side second land portion.

7. The pneumatic tire according to claim 1, wherein the center land portion comprises a plurality of notch grooves in an edge portion on the outer side second land portion side, and said notch grooves comprise chamfered portions surrounding groove opening portions of said notch grooves.

8. The pneumatic tire according to claim 1, wherein the inner side second land portion comprises a plurality of notches in the edge portion on the inner side shoulder land portion side.

9. The pneumatic tire according to claim 8, wherein:

the center land portion comprises notches in the edge portion on the inner side second land portion side, and a length L1 in the tire circumferential direction of the notches in the center land portion and a length L2 in the tire circumferential direction of the notches in the inner side second land portion have a relationship such that 0.45≦

L2/L1≦

0.55.

10. The pneumatic tire according to claim 1, wherein the outer side shoulder land portion comprises lug grooves extending in the tire width direction from the edge portion on the circumferential narrow groove side beyond a tire ground contact edge, and

a distance W4 in the tire width direction from the edge portion on the circumferential narrow groove side of the outer side shoulder land portion to the tire ground contact edge, a groove width W5 of the lug grooves in a region from the edge portion on the circumferential narrow groove side of the outer side shoulder land portion to a distance D6 in the tire width direction, and a groove width W6 of the lug grooves in the tire ground contact edge have relationships such that 0.40≦

D6/W4≦

0.60 and 0.55≦

W5/W6≦

0.75.

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

the outer side second land portion comprises lug grooves penetrating the outer side second land portion, and said lug grooves comprise raised bottom portions in a region from an edge portion on the outer side shoulder land portion side of the outer side second land portion to a predetermined position within the outer side second land portion.

12. The pneumatic tire according to claim 11, wherein notch grooves are positioned substantially on extended lines of the lug grooves of the outer side second land portion.

13. The pneumatic tire according to claim 1, further comprising an indicator designating a mounting direction on a vehicle wherein the circumferential narrow groove side is on the outer side in the vehicle width direction.

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

the center land portion comprises a plurality of notch grooves in an edge portion on the outer side second land portion side, and

the notch grooves are open to the edge portion on the outer side second land portion side of the center land portion and terminate within the center land portion.

15. The pneumatic tire according to claim 14, wherein a length D3 in the tire width direction of the notch grooves and a width W2 of the center land portion have a relationship such that 0.15≦

D3/W2≦

0.35.

16. The pneumatic tire according to claim 14, wherein the notch grooves comprise chamfered portions surrounding groove opening portions of said notch grooves, and a groove width Ws of the notch grooves and a width Wh of the chamfered portions have a relationship such that 2.0≦

Wh/Ws≦

3.0.

17. The pneumatic tire according to claim 16, wherein the chamfered portions are formed throughout an entire periphery of the notch grooves along the groove opening portions and surround terminating portions of the notch grooves in an arc-like configuration.

18. A pneumatic tire comprising:

three circumferential main grooves;

one circumferential narrow groove having a groove width that is less than that of the circumferential main grooves; and

one row of center land portion, a pair of left and right second land portions, and a pair of left and right shoulder land portions partitioned and formed by the circumferential main grooves and the circumferential narrow groove in a tread portion, wherein

when the second land portion and the shoulder land portion in a first region demarcated by the center land portion are referred to as an inner side second land portion and an inner side shoulder land portion, and the second land portion and the shoulder land portion in a second region are referred to as an outer side second land portion and an outer side shoulder land portion,

the circumferential narrow groove is disposed at a position that partitions the outer side second land portion and the outer side shoulder land portion,

the center land portion is a rib that is continuous in a tire circumferential direction, the inner side second land portion and the outer side second land portion are rows of blocks divided in the tire circumferential direction by a plurality of lug grooves,

a groove area ratio S2 of the center land portion, a groove area ratio S1 of the inner side second land portion, and a groove area ratio S3 of the outer side second land portion have a relationship such that S2<

S3<

S1,

a groove width Wd of the circumferential narrow groove and a maximum groove width Wmax of the other three circumferential main grooves have a relationship such that 3.1≦

Wmax/Wd≦

5.0, and

the center land portion comprises a plurality of notch grooves in an edge portion on the outer side second land portion side, and said notch grooves comprise chamfered portions surrounding groove opening portions of said notch grooves.

19. A pneumatic tire comprising:

three circumferential main grooves;

one circumferential narrow groove having a groove width that is less than that of the circumferential main grooves; and

one row of center land portion, a pair of left and right second land portions, and a pair of left and right shoulder land portions partitioned and formed by the circumferential main grooves and the circumferential narrow groove in a tread portion, wherein

when the second land portion and the shoulder land portion in a first region demarcated by the center land portion are referred to as an inner side second land portion and an inner side shoulder land portion, and the second land portion and the shoulder land portion in a second region are referred to as an outer side second land portion and an outer side shoulder land portion,

the circumferential narrow groove is disposed at a position that partitions the outer side second land portion and the outer side shoulder land portion,

the center land portion is a rib that is continuous in a tire circumferential direction, the inner side second land portion and the outer side second land portion are rows of blocks divided in the tire circumferential direction by a plurality of lug grooves,

a groove area ratio S2 of the center land portion, a groove area ratio S1 of the inner side second land portion, and a groove area ratio S3 of the outer side second land portion have a relationship such that S2<

S3<

S1,

a groove width Wd of the circumferential narrow groove and a maximum groove width Wmax of the other three circumferential main grooves have a relationship such that 3.1≦

Wmax/Wd≦

5.0,

the outer side shoulder land portion comprises lug grooves extending in the tire width direction from the edge portion on the circumferential narrow groove side beyond a tire ground contact edge, and

a distance W4 in the tire width direction from the edge portion on the circumferential narrow groove side of the outer side shoulder land portion to the tire ground contact edge, a groove width W5 of the lug grooves in a region from the edge portion on the circumferential narrow groove side of the outer side shoulder land portion to a distance D6 in the tire width direction, and a groove width W6 of the lug grooves in the tire ground contact edge have relationships such that 0.40≦

D6/W4≦

0.60 and 0.55≦

W5/W6≦

0.75.