PNEUMATIC TIRE

• US 20110308680A1
• Filed: 06/06/2011
• Published: 12/22/2011
• Est. Priority Date: 06/17/2010
• Status: Active Grant

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: Sumitomo Rubber Industries Limited
• Inventors: NUMATA, Kazuki
• Granted Patent: US 9,102,203 B2
• Time in Patent Office: Days
• US Class Current: 152/209.17
• CPC Class Codes: B60C 11/0302 directional pattern, i.e. with main rolling direction
• CPC Class Codes: B60C 11/0318 irregular patterns with particular pitch sequence
• CPC Class Codes: B60C 11/12 characterised by the use of narrow slits or incisions, e.g. sipes
• CPC Class Codes: B60C 11/1625 Arrangements thereof in the tread patterns, e.g. irregular

Abstract

A pneumatic tire provided with a tread pattern, wherein a tread half which is one half of the tread pattern on each side of the tire equator is made up of repeat design units arranged circumferentially of the tire. The repeat design units have at least two different circumferential pitch lengths, and the repeat design units are each provided with at least one stud hole.

Claims

1. A pneumatic tire comprising a tread portion provided with a tread pattern wherein a tread half which is one half of the tread pattern on each side of the tire equator Comprises shoulder blocks formed between each tread edge and an axially outermost shoulder circumferential groove adjacent thereto and circumferentially divided by shoulder axial grooves, said tread half is made up of repeat design units arranged circumferentially of the tire wherein the repeat design units are defined by a circumferential-direction line drawn at the tire equator, a circumferential-direction line drawn at said tread edge, and pitch boundary lines drawn perpendicularly to the tire equator, passing through intersecting points of edges of said shoulder axial grooves on one side in a tire circumferential direction with said shoulder circumferential groove, said repeat design units have at least two different circumferential pitch lengths, and said repeat design units are each provided with at least one stud hole for attaching a stud.

2. The pneumatic tire according to claim 1, wherein the number of said repeat design units is in a range of from 56 to 64.

3. The pneumatic tire according to claim 1 or 2, wherein an average ground pressure Psh in a shoulder region between said shoulder circumferential groove and said tread edge is 1.2 to 1.4 times an average ground pressure Per in a crown region between the shoulder circumferential groove on one side of the tire equator and the shoulder circumferential groove on the other side of the tire equator.

4. The pneumatic tire according to claim 1, wherein the number of the stud holes disposed in one tread half is 1.0 to 1.1 times the number of the stud holes disposed in the other tread half.

5. The pneumatic tire according to claim 4, wherein the tread pattern excluding the stud holes and surrounding portions thereof is symmetry with respect to the tire equator or approximately symmetry with respect to the tire equator such that one tread half is circumferentially shifted from the other tread half.

6. The pneumatic tire according to claim 1, wherein said tread half comprises middle blocks, the middle blocks are formed between said shoulder circumferential groove, and a crown circumferential groove disposed axially inside the shoulder circumferential groove, and the middle blocks circumferentially divided by middle axial grooves arranged circumferentially at intervals and extending between a crown circumferential groove disposed axially inside the shoulder circumferential groove, and the stud holes include middle stud holes disposed on the middle blocks and shoulder stud holes disposed on the shoulder blocks.

7. The pneumatic tire according to claim 6, wherein the shoulder stud holes include axially inner shoulder stud holes and axially outer shoulder stud holes positioned axial outside the axially inner shoulder stud holes, and the number of the axially inner shoulder stud holes is 1.0 to 1.2 times the number of the axially outer shoulder stud holes.

8. The pneumatic tire according to claim 7, wherein the inner shoulder stud holes and the outer shoulder stud holes are alternately disposed in the tire circumferential direction.

9. The pneumatic tire according to claim 6, wherein the middle stud holes include axially inner middle stud holes and axially outer middle stud holes disposed axial outside the inner middle stud holes, and the number of the outer middle stud holes is 1.0 to 1.1 times the number of the inner middle stud holes.

10. The pneumatic tire according to claim 9, wherein the axially inner middle stud holes and the axially outer middle stud holes are arranged alternately in the tire circumferential direction.

11. The pneumatic tire according to claim 9, wherein the number of the axially inner shoulder stud holes is 1.0 to 1.1 times the number of the axially outer middle stud holes.