Pneumatic tire

Patent metadata

Field	Value
Publication number	US-10737533-B2
Application number	US-201515519501-A
Country	US
Kind code	B2
Filing date	Oct 5, 2015
Priority date	Oct 16, 2014
Publication date	Aug 11, 2020
Grant date	Aug 11, 2020

Abstract

A pneumatic tire includes a plurality of center lug grooves disposed at intervals in a tire circumferential direction that extend crossing a tire equator line and include a first groove turning portion and a second groove turning portion; a plurality of shoulder lug grooves disposed in the intervals between the plurality of center lug grooves in the tire circumferential direction extending outward in the tire width direction, an inner end in the tire width direction being disposed outward of an end of the center lug groove in the tire width direction; a pair of circumferential main grooves to which the ends of the center lug grooves and the inner ends of the plurality of shoulder lug grooves in the tire width direction alternately connect; and a circumferential secondary groove disposed around the entire circumference of the pneumatic tire with a wave-like shape.

First claim

The invention claimed is:

1. A heavy duty pneumatic tire comprising
a tread portion provided with a tread pattern,
the tread pattern comprising:
a plurality of center lug grooves disposed at intervals in a tire circumferential direction that extend crossing a tire equator line, the plurality of center lug grooves each comprising:
a first end located in a half-tread region that is on a first side of the tire equator line in a tire width direction,
a second end located in a half-tread region on a second side opposite the first side in the tire width direction, and
a first groove turning portion and a second groove turning portion disposed between the first end and the second end, the first groove turning portion turning with a bent shape or a curved shape and being located on a side of the first end, the second groove turning portion turning with a bent shape or a curved shape and being located on a side of the second end;
a plurality of shoulder lug grooves disposed in the intervals in the tire circumferential direction between the plurality of center lug grooves in both of the half-tread regions that extend outward in the tire width direction, the plurality of shoulder lug grooves each comprising:
an outer end in the tire width direction that opens to a ground contact edge on each of opposite sides in the tire width direction, and
an inner end in the tire width direction located on an outside of a position in the tire width direction of the first end or the second end in the tire width direction;
a pair of circumferential main grooves disposed in the respective half-tread regions that extend around an entire circumference of the pneumatic tire in a wave-like shape with a groove width less than that of the plurality of shoulder lug grooves, the pair of circumferential main grooves alternately connecting the respective first end or second end and the inner end of each of the plurality of shoulder lug grooves in the tire width direction;
a plurality of center blocks arranged in the tire circumferential direction and defined by the plurality of center lug grooves and the pair of circumferential main grooves;
a plurality of shoulder blocks arranged in the tire circumferential direction and defined by the plurality of shoulder lug grooves and the pair of circumferential main grooves; and
a circumferential secondary groove with a wave-like shape disposed around the entire circumference of the pneumatic tire, the circumferential secondary groove intersecting the plurality of center lug grooves in a manner such that in each of the plurality of center blocks, the circumferential secondary groove alternately connects the first groove turning portion and the second groove turning portion, the first groove turning portion being in a center lug groove of adjacent center lug grooves of the plurality of center lug grooves on either side of each of the plurality of center blocks in the tire circumferential direction, the second groove turning portion being in the other center lug groove of the adjacent center lug grooves, and portions of the circumferential secondary groove on both sides in the tire circumferential direction of each of the center lug grooves share a position of the first groove turning portion or the second groove turning portion in the tire width direction;
the circumferential secondary groove comprising in each of the plurality of center blocks a third groove turning portion that turns with a bent shape or a curved shape located on a side of the first groove turning portion and a fourth groove turning portion that turns with a bent shape or a curved shape located on a side of the second groove turning portion.

2. The heavy duty pneumatic tire according to claim 1 , wherein a relationship 0.20≤LSG/LSB≤0.35 is satisfied, where LSB is a length in the tire circumferential direction of end portions of the plurality of shoulder blocks on a side of the ground contact edge, and LSG is a groove width of end portions of the plurality of shoulder lug grooves on a side of the ground contact edge.

3. The heavy duty pneumatic tire according to claim 1 , further comprising a raised bottom portion in each of the pair of circumferential main grooves where the groove becomes partially shallower.

4. The heavy duty pneumatic tire according to claim 3 , wherein a relationship D 2 /T<0.05 is satisfied, where D 2 is a groove depth of the raised bottom portion and T is a ground contact width of the tread portion in the tire width direction.

5. The heavy duty pneumatic tire according to claim 1 , wherein a relationship 0.9≤WSB/LSB≤1.3 is satisfied, where LSB is a length in the tire circumferential direction of end portions of the plurality of shoulder blocks on a side of the ground contact edge, and WSB is a maximum width of the plurality of shoulder blocks in the tire width direction.

6. The heavy duty pneumatic tire according to claim 1 , wherein
a distance W 1 from end portions of the plurality of center lug grooves to the tire equator line is at least 0.15 times a ground contact width T of the tread portion in the tire width direction; and
a distance W 2 from inner ends of the plurality of shoulder lug grooves in the tire width direction to the tire equator line is at most 0.30 times the ground contact width T.

7. The heavy duty pneumatic tire according to claim 1 , wherein a relationship 0.05≤A/WB≤0.20 is satisfied, where WB is a maximum width of the plurality of center blocks in the tire width direction, and A is a maximum distance from the circumferential secondary groove to the tire equator line in the tire width direction.

8. The heavy duty pneumatic tire according to claim 1 , wherein corner portions with an obtuse angle are formed in the plurality of center blocks corresponding to the pair of circumferential main grooves.

9. The heavy duty pneumatic tire according to claim 1 , wherein a groove width of the pair of circumferential main grooves and a groove width of the plurality of center lug grooves range from 7 mm to 20 mm.

10. The heavy duty pneumatic tire according to claim 1 , wherein the heavy duty pneumatic tire is mounted on a construction vehicle or an industrial vehicle.

11. The heavy duty pneumatic tire according to claim 1 , wherein
the first groove turning portion disposed on the first side bends or curves protruding out toward a third side in the tire circumferential direction,
the second groove turning portion disposed on the second side bends or curves protruding out toward a fourth side opposite the third side in the tire circumferential direction; and
an inclination angle with respect to the tire width direction of a first straight line that joins the first end and a protruding end where the first groove turning portion protrudes toward the third side in the tire circumferential direction and an inclination angle with respect to the tire width direction of a second straight line that joins the second end and a protruding end where the second groove turning portion protrudes toward the fourth side in the tire circumferential direction are greater than an inclination angle with respect to the tire width direction of a third straight line that joins the first end and the second end of each of the plurality of center lug grooves, the straight lines following center positions in a groove width direction of the center lug grooves.

12. The heavy duty pneumatic tire according to claim 1 , wherein
an inclination angle with respect to the tire width direction of a fourth straight line that joins a third end of the circumferential secondary groove within the plurality of center blocks on a side of the first groove turning portion and the third groove turning portion and

Assignees

• C/O The Yokohama Rubber Co Ltd
• Yokohama Rubber Co Ltd

Inventors

• Yamaguchi Yukihito
• KAKUTA Shoei
• Hamanaka Hideki
• Tauchi Risa
• Sato Toshiyuki

Classifications

• B60C11/13

  characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping · CPC title

• B60C11/03 Primary

  Tread patterns · CPC title

• B60C11/0311 Primary

  Patterns comprising tread lugs arranged parallel or oblique to the axis of rotation · CPC title

• B60C11/1369

  Tie bars for linking block elements and bridging the groove · CPC title

• B60C2011/0372

  with particular inclination angles · CPC title