LOW NOISE TIRE TREAD

Abstract

A tread has a midcircumferential plane, a first axial tread edge, and a second axial tread edge. The tread includes a first shoulder rib extending circumferentially about a perimeter of the tread, a second shoulder rib extending circumferentially about the perimeter of the tread, and a first intermediate rib extending circumferentially about the perimeter of the tread. The first intermediate rib is defined by a first and a second circumferentially extending groove disposed to each axial side of the first intermediate rib. The first intermediate rib has a first plurality of angled sipes extending both axially and circumferentially at an angle between 50 and 70 relative to the first circumferentially extending groove. The angled sipes each have a radial depth of between 1.0 mm and 3.0 mm.

Claims

1. A tread for a tire having a midcircumferential plane, a first axial tread edge and a second axial tread edge, the tread comprising: a first shoulder rib extending circumferentially about a perimeter of the tread; a second shoulder rib extending circumferentially about the perimeter of the tread and a first intermediate rib extending circumferentially about the perimeter of the tread, the first intermediate rib being defined by a first and a second circumferentially extending groove disposed to each axial side of the first intermediate rib, the first intermediate rib having a plurality of angled sipes extending both axially and circumferentially at an angle between 50 and 70 relative to the first circumferentially extending groove, the angled sipes each having a radial depth of between 1.0 mm and 3.0 mm.

2. The tread as set forth in claim 1 wherein the angled sipes have a uniform radial depth between 1.5 mm and 2.5 mm.

3. The tread as set forth in claim 1 wherein the angled sipes extend at an angle of about 60 relative to the first circumferentially extending groove.

4. The tread as set forth in claim 1 wherein the angled sipes have a uniform radial depth of about 2.0 mm.

5. The tread as set forth in claim 1 further including a second intermediate rib extending circumferentially about the perimeter of the tread, the second intermediate rib being defined by the first circumferentially extending groove and a third circumferentially extending groove disposed to each axial side of the second intermediate rib, the second intermediate rib having a plurality of angled sipes extending both axially and circumferentially at an angle between 50 and 70 relative to the third circumferentially extending groove, the angled sipes each having a radial depth of between 1.0 mm and 3.0 mm.

6. The tread as set forth in claim 5 further including a third intermediate rib extending circumferentially about the perimeter of the tread, the third intermediate rib being defined by the third circumferentially extending groove and a fourth circumferentially extending groove disposed to each axial side of the third intermediate rib, the third intermediate rib having a plurality of angled sipes extending both axially and circumferentially at an angle between 50 and 70 relative to the fourth circumferentially extending groove, the angled sipes each having a radial depth of between 1.0 mm and 3.0 mm.

7. The tread as set forth in claim 6 wherein the second intermediate rib is axially disposed between the first intermediate rib and the third intermediate rib.

8. The tread as set forth in claim 6 wherein the angled sipes of the first intermediate rib extend to a blind end at an axial location about midway across the first intermediate rib.

9. The tread as set forth in claim 6 wherein the angled sipes of the second intermediate rib extend to a blind end at an axial location about midway across the second intermediate rib.

10. The tread as set forth in claim 6 wherein the angled sipes of the third intermediate rib extend to a blind end at an axial location about midway across the third intermediate rib.

11. A method for reducing pass-by-noise of a tread, said method comprising the steps of: extending a first shoulder rib circumferentially about a perimeter of the tread; extending a second shoulder rib circumferentially about the perimeter of the tread; extending a first intermediate rib circumferentially about the perimeter of the tread; defining the first intermediate rib with a first and a second circumferentially extending groove disposed to each axial side of the first intermediate rib; extending a first plurality of angled sipes axially and circumferentially across the first intermediate rib at an angle between 50 and 70 relative to the second circumferentially extending groove; and extending the angled sipes to a radial depth of between 1.0 mm and 3.0 mm.

12. The method as set forth in claim 11 further including the step of extending the angled sipes to a uniform radial depth between 1.5 mm and 2.5 mm.

13. The method as set forth in claim 11 further including the step of extending the angled sipes at an angle of about 60 relative to the first circumferentially extending groove.

14. The method as set forth in claim 11 further including the step of extending the angled sipes have a uniform radial depth of about 2.0 mm.

15. The method as set forth in claim 11 further including the steps of extending a second intermediate rib circumferentially about the perimeter of the tread, defining the second intermediate rib by the first circumferentially extending groove and a third circumferentially extending groove disposed to each axial side of the second intermediate rib, extending a second plurality of angled sipes both axially and circumferentially across the second intermediate rib at an angle between 50 and 70 relative to the third circumferentially extending groove, and extending the second plurality of angled sipes each to a radial depth of between 1.0 mm and 3.0 mm.

16. The method as set forth in claim 15 further including the steps of extending a third intermediate rib circumferentially about the perimeter of the tread, defining the third intermediate rib the third circumferentially extending groove and a fourth circumferentially extending groove disposed to each axial side of the third intermediate rib, extending a third plurality of angled sipes both axially and circumferentially across the third intermediate rib at an angle between 50 and 70 relative to the fourth circumferentially extending groove, and extending the third plurality of angled sipes each to a radial depth of between 1.0 mm and 3.0 mm.

17. The method as set forth in claim 16 further including the step of extending the second intermediate rib axially between the first intermediate rib and the third intermediate rib.

18. The method as set forth in claim 16 further including the step of extending the first plurality of angled sipes to a blind end at an axial location about midway across the first intermediate rib.

19. The method as set forth in claim 16 further including the step of extending the second plurality of angled sipes to a blind end at an axial location about midway across the second intermediate rib.

20. The method as set forth in claim 16 further including the step of extending the third plurality of angled sipes to a blind end at an axial location about midway across the third intermediate rib.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0096] The features of the present invention will become apparent to those skilled in the art to which the present invention relates from reading the following specifications with reference to the accompanying drawings, in which:

[0097] FIG. 1 is a schematic perspective view of a tread of a tire in accordance with the present invention;

[0098] FIG. 2 is a schematic front elevation view of the tire of FIG. 1; and

[0099] FIG. 3 is a schematic sectional view taken along line 3-3 in FIG. 2.

DETAILED DESCRIPTION OF EXAMPLES OF THE PRESENT INVENTION

[0100] An example tire 2 in accordance with the present invention is illustrated in FIGS. 1-3. The tire 2 may be pneumatic or non-pneumatic. The tire 2 may be mounted on a vehicle wheel and connected to an axle of a vehicle, such as a passenger car, light truck, or the like. The tire 2 may be rotatable about a longitudinal rotation axis of the axle. A mid-circumferential plane M may extend perpendicular to the rotation axis and bisect the tire 2. The tire 2 may include a tread 20 and a radial carcass extending between a pair of inextensible beads, as shown in the example tire of U.S. Pat. No. 5,421,387, incorporated herein by reference in its entirety. Axially opposite ends of the carcass may be secured to a respective bead. The carcass may be flanked by two sidewalls. A belt package may be located between the carcass and the tread 20.

[0101] The tread 20 may have a tread width TW2 defined as above, or an axial distance widthwise across the tire 2 measured within the footprint of the tire when the tire 2 is contacting a road surface and when the tire 2 is inflated to a design pressure and loaded to a rated load. The tread width TW2 may be axially equidistant about the mid-circumferential plane M of the tire 2 (FIG. 3). The tread 20 may include five longitudinally extending ribs: a first rib 22, a second rib 24, a third rib 25, a fourth rib 26, and a fifth rib 28, spaced axially apart widthwise over the tread width TW2. The longitudinally extending ribs 22, 24, 25, 26, 28 may be separated by uninterrupted circumferential grooves 42, 44, 46, 48. Each circumferential groove 42, 44, 46, 48 has a respective width measured perpendicular to the mid-circumferential plane M. Each circumferential rib 22, 24, 25, 26, 28 may have a respective rib width measured perpendicular to the mid-circumferential plane M. The center rib 25 may be bisected by the mid-circumferential plane M.

[0102] The first shoulder rib 22 may have first sipes 221, second sipes 222, third sipes 223, and fourth sipes 224. The first sipes 221 may extend axially outward from the axially outermost groove 42 toward a first tread edge 21. The first sipes 221 may simultaneously also curve in a circumferential direction adjacent the axially outer ends of the second and third sipes 222, 223 of the first shoulder rib 2 and parallel the first tread edge 21. The second sipes 222 may extend axially outward from the axially outermost groove 42 toward the first sipes 221 and the first tread edge 21. The third sipes 223 may extend axially outward from the axially outermost groove 42 toward the first sipes 221 and the first tread edge 21. The fourth sipes 224 may extend axially outward from the axially outermost groove 42 toward the first tread edge 21. Adjacent the axially outer edges of the fourth sipes 224 may be check mark shaped fifth sipes 225 (FIG. 2).

[0103] The second intermediate rib 24 may have angled sipes 241 extending axially inward from the axially outermost groove 42 to a blind end at an axial location about midway across the second rib 24. The angled sipes 241 may extend axially and circumferentially at an angle between 50 and 70, or about 60 relative to the axially outermost groove 42. The angled sipes 241 may have a uniform radial depth between 1.0 mm and 3.0 mm, or 1.5 mm and 2.5 mm, or about 2.0 mm.

[0104] The third center rib 25 may be defined axially between the intermediate groove 44 and the intermediate groove 46. The third rib 25 may have angled sipes 251 extending axially from the intermediate groove 44 to the intermediate groove 46. The angled sipes 251 may extend axially and circumferentially at an angle between 50 and 70, or about 60 relative to the intermediate grooves 44, 46. The angled sipes 251 may have a uniform radial depth between 1.0 mm and 3.0 mm, or 1.5 mm and 2.5 mm, or about 2.0 mm.

[0105] The fourth intermediate rib 26 may have angled sipes 261 extending axially inward from the axially outermost groove 48 to the intermediate groove 46 across the fourth rib 26. The angled sipes 261 may extend axially and circumferentially at an angle between 50 and 70, or about 60 relative to the axially outermost groove 48. The angled sipes 241 may have a uniform radial depth between 1.0 mm and 3.0 mm, or 1.5 mm and 2.5 mm, or about 2.0 mm.

[0106] The fifth shoulder rib 28 may have axial sipes 281 that extend axially outward from the axially outermost groove 48 toward a second tread edge 23. Each of the angled sipes 241, 251, 261 may extend at the same angle relative to all of the circumferential grooves 42, 44, 46, 48 (FIG. 2). The shoulder sipes 221, 222, 223, 224, 281 may increase in width as they extend axially outward (FIG. 2). Such a tire 2 as described above may thus exhibit a pass-by-noise level below 65.0 dB(A), as well as provide acceptable rolling resistance, impact robustness, and ride and handling.

[0107] From the above description of an example of the present invention, those skilled in the art may perceive improvements, changes, and/or modifications. Such improvements, changes, and/or modifications within the skill of the art are intended to be covered by the appended claims.