Tire

Patent metadata

Field	Value
Publication number	US-11654720-B2
Application number	US-202016945209-A
Country	US
Kind code	B2
Filing date	Jul 31, 2020
Priority date	Aug 7, 2019
Publication date	May 23, 2023
Grant date	May 23, 2023

Abstract

A tire comprises a tread portion whose shoulder land part is provided with a narrow circumferential groove having an axially inner wall surface, an axially outer wall surface and a groove bottom including a deepest point. The axially inner wall surface has a radially inner curved portion concaved toward the axially inside, and the axially outer wall surface has a radially inner curved portion concaved toward the axially outside. the radially outer end of the radially inner curved portion of the axially inner wall surface is positioned radially inside the radially outer end of the radially inner curved portion of the axially outer wall surface.

First claim

The invention claimed is:

1. A tire comprising:
a tread portion having a tread surface and provided with a shoulder land part including a tread edge,
the shoulder land part provided with a narrow circumferential groove which extends in the tire circumferential direction and has an axially inner wall surface, an axially outer wall surface and a groove bottom including a deepest point,

wherein
in a cross section of the narrow circumferential groove being perpendicular to the longitudinal direction of the narrow circumferential groove:
the axially inner wall surface is composed of a radially outer flat portion and a radially inner curved portion, wherein
the radially outer flat portion extends in a tire radial direction from the tread surface, and
the radially inner curved portion is composed of
a convex surface extending radially inwardly from the radially inner end of the radially outer flat portion, and
a concave surface extending from the convex surface to the deepest point of the groove bottom, and

in the cross section of the narrow circumferential groove being perpendicular to the longitudinal direction of the narrow circumferential groove:
the axially outer wall surface is composed of a radially outer flat portion and a radially inner curved portion, wherein
the radially outer flat portion extends in the tire radial direction from the tread surface, and
the curved portion is composed of
a convex surface extending radially inwardly from the radially inner end of the radially outer flat portion, and
a concave surface extending from the convex surface to the deepest point of the groove bottom,

wherein
in the cross section of the narrow circumferential groove being perpendicular to the longitudinal direction of the narrow circumferential groove:
the radially outer flat portion of the axially inner wall surface and the radially outer flat portion of the axially outer wall surface are parallel with each other, and have a widthwise center line therebetween which defines a groove center line of the narrow circumferential groove;
the deepest point is positioned axially outside the groove center line of the narrow circumferential groove;
the radially inner end of the radially outer flat portion of the axially outer wall surface is positioned radially outside the radially inner end of the radially outer flat portion of the axially inner wall surface;
the radially outer end of the radially outer flat portion of the axially outer wall surface is positioned radially inside the radially outer end of the radially outer flat portion of the axially inner wall surface; and
a distance L 4 in the tire axial direction between the axially innermost end of the curved portion and the radially outer flat portion of the axially inner wall surface is smaller than a distance L 5 in the tire axial direction between the axially outermost end 13 k of the radially inner curved portion and the radially outer flat portion of the axially outer wall surface.

2. The tire according to claim 1 , wherein the deepest point of the groove bottom is positioned axially outside a radially inward extension of the radially outer flat portion of the axially outer wall surface.

3. The tire according to claim 2 , wherein
the shoulder land part is defined between the tread edge and a shoulder main groove extending continuously in the tire circumferential direction, whereby the shoulder land part is divided into an axially outer portion between the narrow circumferential groove and the tread edge, and an axially inner portion between the narrow circumferential groove and the shoulder main groove,
the radially outer surface of the axially outer portion is positioned radially inside the radially outer surface of the axially inner portion, and
the radially outer surface of the axially outer portion is parallel with the radially outer surface of the axially inner portion.

4. The tire according to claim 3 , wherein an axial dimension Ws of the radially outer surface of the radially outer surface of the axially outer portion is in a range from 3% to 8% of an axial dimension Wt of the shoulder land part.

5. The tire according to claim 1 , wherein
the shoulder land part is defined between the tread edge and a shoulder main groove extending continuously in the tire circumferential direction, whereby the shoulder land part is divided into an axially outer portion between the narrow circumferential groove and the tread edge, and an axially inner portion between the narrow circumferential groove and the shoulder main groove, and
the radially outer surface of the axially outer portion is positioned radially inside the radially outer surface of the axially inner portion.

6. The tire according to claim 5 , wherein the groove depth of the narrow circumferential groove is not more than 1.5 times the groove depth of the shoulder main groove.

7. The tire according to claim 5 , wherein an axial dimension Ws 1 of the axially outer portion measured at the axially outermost point of the radially inner curved portion of the axially outer wall surface is in a range from 1.0 to 1.4 times the axial dimension Ws of the radially outer surface of the axially outer portion.

8. The tire according to claim 5 , wherein
the shoulder main groove is a straight groove having an axially outer wall surface and an axially inner wall surface,
the axially outer wall surface and the axially inner wall surface are each inclined at an angle with respect to the tire radial direction which is cyclically varied in the tire circumferential direction, and
cycles of variation of the angle of the axially outer wall surface and cycles of variation of the angle of the axially inner wall surface are the same but shifted from each other by a half cycle.

9. The tire according to claim 8 , wherein the axially inner portion is provided with no grooves other than shoulder narrow axial grooves extending axially outwardly from the shoulder main groove and terminate within the axially inner portion.

10. The tire according to claim 9 , wherein the tread portion is provided with a crown main groove continuously extending in the tire circumferential direction between the shoulder main groove and a tire equator.

11. The tire according to claim 10 , wherein
the crown main groove is a straight groove having an axially outer wall surface and an axially inner wall surface,
the axially outer wall surface and the axially inner wall surface are each inclined at an angle with respect to the tire radial direction which is cyclically varied in the tire circumferential direction, and
cycles of variation of the angle of the axially outer wall surface and cycles of variation of the angle of the axially inner wall surface are the same but shifted from each other by a half cycle.

12. The tire according to claim 5 , wherein an axial dimension Ws of the radially outer surface of the radially outer surface of the axially outer portion is in a range from 3% to 8% of an axial dimension Wt of the shoulder land part.

13. The tire according to claim 1 , wherein the groove width of the narrow circumferential groove measured at its opened top is not more than the maximum width of the narrow circumferential groove occurring on its groove bottom side.

Assignees

• Sumitomo Rubber Ind

Inventors

• TANIGUCHI Hidetoshi

Classifications

• B60C11/04

  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 title

• B60C11/1259

  Depth of the sipe · CPC title

• B60C2011/0348

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

• B60C11/0306

  Patterns comprising block rows or discontinuous ribs · CPC title

• B60C2011/0351

  Shallow grooves, i.e. having a depth of less than 50% of other grooves · CPC title