Heavy-duty pneumatic tire

Patent metadata

Field	Value
Publication number	US-10029517-B2
Application number	US-201515523326-A
Country	US
Kind code	B2
Filing date	Oct 19, 2015
Priority date	Oct 31, 2014
Publication date	Jul 24, 2018
Grant date	Jul 24, 2018

Abstract

A heavy-duty pneumatic tire includes a tread pattern including center lug grooves, shoulder lug grooves, a pair of circumferential primary grooves formed in wave-like shapes by alternately connecting ends of the center lug grooves and ends of the shoulder lug grooves and having a smaller width than the width of the shoulder lug grooves, center blocks defined by the center lug groove and the circumferential primary grooves, and a circumferential secondary groove extending in the tire circumferential direction so as to divide regions of the center blocks. The belt portion includes two or greater pairs of belts. The ratio of the width W8 of a belt having a smaller width in each of the belt pairs to the width W7 of a belt having a greater width is 0.75 or greater and 0.90 or less.

First claim

The invention claimed is:

1. A heavy-duty pneumatic tire comprising a tread pattern and a belt portion,
the tread pattern comprising:
a plurality of center lug grooves separated from each other in a tire circumferential direction, the center lug grooves extending in half-tread regions on a first side and a second side of a tire equator line in a tire width direction so as to cross the tire equator line, and the center lug grooves including both ends;
shoulder lug grooves positioned, in the tire circumferential direction, between adjacent center lug grooves in the tire circumferential direction among the center lug grooves, the shoulder lug grooves extending outward in the tire width direction in the half-tread regions, and the shoulder lug grooves having ends on an outside in the tire width direction opening at ground contact ends on both sides in the tire width direction and ends on an inside in the tire width direction being positioned outward in the tire width direction with respect to ends of the center lug grooves;
a pair of circumferential primary grooves formed in wave-like shapes in the respective half-tread regions over an entire periphery of the tire by alternately connecting the ends of the center lug grooves and the ends of the shoulder lug grooves on the inside in the tire width direction, the circumferential primary grooves having a smaller width than a width of the shoulder lug grooves;
a plurality of center blocks defined by the center lug grooves and the pair of circumferential primary grooves and aligned in a row in the tire circumferential direction; and
a circumferential secondary groove extending along the tire equator line in the tire circumferential direction so as to divide regions of the center blocks;
the belt portion comprising at least a first belt disposed on an innermost side in a tire radial direction, a second belt having a different width from the first belt, a third belt, and a fourth belt having a different width from the third belt in order from the first belt toward an outside in the tire radial direction, the belt portion having a laminated structure of belt layers composed of at least two belt pairs, the two belt pairs being a pair of the first belt and the second belt and a pair of the third belt and the fourth belt;
the belt pairs of the belt layers each having a ratio W 8 /W 7 of 0.75 or greater and 0.80 or less, the ratio indicating a width W 8 of a belt having a smaller width in the belt layer to a width W 7 of a belt having a greater width in the belt layer; and
fourth and subsequent belts from an innermost belt in the tire radial direction toward the outside in the tire radial direction in the laminated structure of the belt portion each having a width equal to or greater than a maximum width WB of the center blocks in the tire width direction.

2. The heavy-duty pneumatic tire according to claim 1 , wherein the circumferential primary grooves each comprise a raised bottom portion formed by partially making a groove depth smaller.

3. The heavy-duty pneumatic tire according to claim 2 , wherein a depth D 2 of the raised bottom portion and a tread width T in the tire width direction of a tread portion having the tread pattern formed thereon satisfy a relationship of D 2 /T <0.05.

4. The heavy-duty pneumatic tire according to claim 1 , wherein the circumferential secondary groove comprises at least two groove turning portions changing an extending direction of the groove in a region between adjacent center lug grooves in the tire circumferential direction.

5. The heavy-duty pneumatic tire according to claim 1 , wherein orientations of reinforcing cords of belts having greater widths in the belt pairs of the belt layers are inclined toward a same side in the tire width direction with respect to the tire circumferential direction.

6. The heavy-duty pneumatic tire according to claim 1 , wherein pairs of adjacent belts in the belt portion each form cross layers by inclining reinforcing cords of the belts toward opposite sides in the tire width direction with respect to the tire circumferential direction.

7. The heavy-duty pneumatic tire according to claim 1 , wherein a belt positioned closer to the outside in the tire radial direction has a greater width among the belts having greater widths in the belt pairs of the belt layers.

8. The heavy-duty pneumatic tire according to claim 1 , wherein the belt portion comprises a first belt pair positioned innermost in the tire radial direction, a second belt pair laminated outside the first belt pair in the tire radial direction, and a third belt pair laminated outside the second belt pair in the tire radial direction;
a ratio WB/W 3 of the maximum width WB of the center blocks in the tire width direction to a width W 3 of a belt having a smaller width in the third belt pair is 0.5 or greater and 0.8 or less; and
the width W 3 is greater than a width W 2 of a belt having a smaller width in the second belt pair.

9. The heavy-duty pneumatic tire according to claim 1 , wherein the belt portion comprises a first belt pair positioned innermost in the tire radial direction, a second belt pair laminated outside the first belt pair in the tire radial direction, and a third belt pair laminated outside the second belt pair in the tire radial direction; and
a width W 1 of a belt having a smaller width in the first belt pair is smaller than the maximum width WB of the center blocks in the tire width direction.

10. The heavy-duty pneumatic tire according to claim 1 , wherein the center blocks are provided with corners in correspondence with the circumferential primary grooves, the corners having obtuse angles.

11. The heavy-duty pneumatic tire according to claim 1 , wherein widths of the circumferential primary grooves and the center lug grooves are 7 mm or greater and 20 mm or less.

12. The heavy-duty pneumatic tire according to claim 1 being fitted to a construction or industrial vehicle.

13. The heavy-duty pneumatic tire according to claim 1 , wherein the circumferential secondary groove extends from a single position of each of the center lug grooves in the tire circumferential direction, on opposites sides of each of the center lug grooves.

14. A heavy-duty pneumatic tire comprising a tread pattern and a belt portion,
the tread pattern comprising:
a plurality of center lug grooves separated from each other in a tire circumferential direction, the center lug grooves extending in half-tread regions on a first side and a second side of a tire equator line in a tire width direction so as to cross the tire equator line, and the center lug grooves including both ends;
shoulder lug grooves positioned, in the tire circumferential direction, between adjacent center lug grooves in the tire circumferential direction among the center lug grooves, the shoulder lug grooves extending outward in the tire width direction in the half-tread regions, and the shoulder lug grooves having ends on an outside in the tire width direction opening at ground contact ends on both sides in the tire width direction and ends on an inside in the tire width direction being positioned outward in the tire width direction with respect to ends of the center lug grooves;
a pair of circumferential primary grooves formed in wave-like shapes in the respective half-tread regions over an entire periphery of the tire by alternately connecting the ends of the center lug grooves and the ends of the shoulder lug grooves on the inside in the tire width direction, the circumferential primary grooves having a smaller width than a width of the shoulder lug grooves;
a plurality of center blocks defined by

Assignees

• Yokohama Rubber Co Ltd

Inventors

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

Classifications

• B60C11/0311

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

• B60C2011/0355

  characterised by depth · CPC title

• B60C2200/065

  for construction vehicles · CPC title

• B60C11/03 Primary

  Tread patterns · CPC title

• B60C2011/0348

  Narrow grooves, i.e. having a width of less than 4 mm · CPC title