Pneumatic run flat tire

Patent metadata

Field	Value
Publication number	US-9340073-B2
Application number	US-201213604458-A
Country	US
Kind code	B2
Filing date	Sep 5, 2012
Priority date	Sep 28, 2011
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

A pneumatic run flat tire includes an inner side reinforcing rubber layer having a falcated cross-section and an outer side reinforcing rubber layer having a center of gravity position in a meridian cross-section that is positioned inward in a tire radial direction of a tire maximum width position disposed in a side wall portion. Volumes of the inner side reinforcing rubber layer and the outer side reinforcing rubber layer are each different on a vehicle inner side and a vehicle outer side when mounted on a vehicle.

First claim

What is claimed is:

1. A pneumatic run flat tire comprising a carcass layer mounted between a pair of left and right bead portions, a belt layer disposed on an outer circumferential side of the carcass layer in a tread portion, and an inner side reinforcing rubber layer having a falcated cross-section disposed on an inner side in a tire width direction of the carcass layer in a side wall portion; wherein
an outer side reinforcing rubber layer is disposed on an outer side in the tire width direction of the carcass layer from the bead portion throughout the side wall portion, a center of gravity position in a meridian cross-section of the outer side reinforcing rubber layer is positioned inward in a tire radial direction of a position where tire width is greatest, volumes of the inner side reinforcing rubber layer and the outer side reinforcing rubber layer are each different on a vehicle inner side and a vehicle outer side when the pneumatic run flat tire is mounted on a vehicle, a ratio V1 out /V1 in of a volume V1 out of the inner side reinforcing rubber layer on the vehicle outer side to a volume V1 in of the inner side reinforcing rubber layer on the vehicle inner side is from 1.10 to 1.35, and a ratio V2 in /V2 out of a volume V2 in of the outer side reinforcing rubber layer on the vehicle inner side to a volume V2 out of the outer side reinforcing rubber layer on the vehicle outer side is from 1.10 to 1.50.

2. The pneumatic run flat tire according to claim 1 , wherein, of the inner side reinforcing rubber layer, at least the inner side reinforcing rubber layer positioned on the vehicle inner side is constituted by a rubber composition comprising from 0.2 to 10 parts by weight of a cyclic polysulfide expressed by formula (1) below per 100 parts by weight of a sulfur vulcanizable rubber:

wherein, R is a substituted or unsubstituted oxyalkylene group having from 2 to 20 carbons; n is an integer from 1 to 15; and x is a number from 3 to 5 on average.

3. The pneumatic run flat tire according to claim 2 , wherein the R group in the formula (1) is —CH 2 —CH 2 —O—CH 2 —O—CH 2 —CH 2 —.

4. The pneumatic run flat tire according to claim 3 , wherein a tan δ at 60° C. of the rubber composition constituting the inner side reinforcing rubber layer and of the rubber composition constituting the outer side reinforcing rubber layer is from 0.01 to 0.08; and a dynamic elastic modulus E′ at 60° C. of the rubber composition constituting the inner side reinforcing rubber layer and of the rubber composition constituting the outer side reinforcing rubber layer is from 4.5 to 13 MPa.

5. The pneumatic run flat tire according to claim 4 , wherein a belt cover layer disposed on an outer side in the radial direction of the belt layer is constituted by a composite cord comprising two types of organic fibers having differing properties.

6. The pneumatic run flat tire according to claim 1 , wherein, of the outer side reinforcing rubber layer, at least the outer side reinforcing rubber layer positioned on the vehicle outer side is constituted by a rubber composition comprising from 0.2 to 10 parts by weight of a cyclic polysulfide expressed by formula (1) below per 100 parts by weight of a sulfur vulcanizable rubber:

wherein, R is a substituted or unsubstituted oxyalkylene group having from 2 to 20 carbons; n is an integer from 1 to 15; and x is a number from 3 to 5 on average.

7. The pneumatic run flat tire according to claim 6 , wherein the R group in the formula (1) is —CH 2 —CH 2 —O—CH 2 —O—CH 2 —CH 2 —.

8. The pneumatic run flat tire according to claim 7 , wherein a tan δ at 60° C. of the rubber composition constituting the inner side reinforcing rubber layer and of the rubber composition constituting the outer side reinforcing rubber layer is from 0.01 to 0.08; and a dynamic elastic modulus E′ at 60° C. of the rubber composition constituting the inner side reinforcing rubber layer and of the rubber composition constituting the outer side reinforcing rubber layer is from 4.5 to 13 MPa.

9. The pneumatic run flat tire according to claim 8 , wherein a belt cover layer disposed on an outer side in the radial direction of the belt layer is constituted by a composite cord comprising two types of organic fibers having differing properties.

10. The pneumatic run flat tire according to claim 1 , wherein a tan δ at 60° C. of the rubber composition constituting the inner side reinforcing rubber layer and of the rubber composition constituting the outer side reinforcing rubber layer is from 0.01 to 0.08; and a dynamic elastic modulus E′ at 60° C. of the rubber composition constituting the inner side reinforcing rubber layer and of the rubber composition constituting the outer side reinforcing rubber layer is from 4.5 to 13 MPa.

11. The pneumatic run flat tire according to claim 1 , wherein a belt cover layer disposed on an outer side in the radial direction of the belt layer is constituted by a composite cord comprising two types of organic fibers having differing properties.

12. The pneumatic run flat tire according to claim 11 , wherein the composite cord comprises: an organic fiber having relatively high stretchability and a low elastic modulus and an organic fiber having relatively low stretchability and a high elastic modulus.

13. The pneumatic run flat tire according to claim 1 , wherein, of the inner side reinforcing rubber layer, at least the inner side reinforcing rubber layer positioned on the vehicle inner side is constituted by a rubber composition comprising from 0.2 to 10 parts by weight of a cyclic polysulfide expressed by formula (1) below per 100 parts by weight of a sulfur vulcanizable rubber:

wherein, R is represented by —CH 2 CH 2 OCH 2 CH 2 —, —(CH 2 CH 2 O) 2 CH 2 CH 2 —, —(CH 2 CH 2 O) 3 CH—CH 2 —, —(CH 2 CH 2 O) 4 CH 2 CH 2 —, —(CH 2 CH 2 O) 5 CH 2 CH 2 —, —(CH 2 CH 2 O) 2 CH 2 —, or —CH 2 CH 2 OCH 2 OCH 2 CH 2 —; n is an integer from 1 to 15; and x is a number from 3 to 5 on average.

14. The pneumatic run flat tire according to claim 1 , wherein, of the inner side reinforcing rubber layer, at least the inner side reinforcing rubber layer positioned on the vehicle inner side is constituted by a rubber composition comprising from 0.2 to 10 parts by weight of a cyclic polysulfide expressed by formula (1) below per 100 parts by weight of a sulfur vulcanizable rubber:

wherein, R is a substituted or unsubstituted oxyalkylene group having from 2 to 20 carbons; n is an integer from 1 to 15; and x is a number from 3.5 to 4.5 on average.

15. The pneumatic run flat tire according to claim 1 , wherein, of the inner side reinforcing rubber layer, at least the inner side reinforcing rubber layer positioned on the vehicle inner side is constituted by a rubber composition comprising from 0.2 to 10 parts by weight of a cyclic polysulfide expressed by formula (1) below per 100 parts by weight of a sulfur vulcanizable rubber:

wherein, R is a substituted or unsubstituted oxyalkylene group having from 2 to 20 carbons; n is an integer from 1 to 10; and x is a number from 3 to 5 on average.

Assignees

• Horiuchi Kenji
• Yokohama Rubber Co Ltd

Inventors

• Horiuchi Kenji

Classifications

• B60C9/005

  Reinforcements made of different materials, e.g. hybrid or composite cords · CPC title

• B60C9/22

  the plies being arranged with all cords disposed along the circumference of the tyre · CPC title

• B60C15/0018 Primary

  not folded around the bead core, e.g. floating or down ply · CPC title

• B60C15/0054

  with ply turn-up portion parallel and adjacent to carcass main portion · CPC title

• Y10T152/10504

  Asymmetric tyre · CPC title