Pneumatic tire and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-12122193-B2
Application number	US-202217830484-A
Country	US
Kind code	B2
Filing date	Jun 2, 2022
Priority date	Jun 28, 2021
Publication date	Oct 22, 2024
Grant date	Oct 22, 2024

Abstract

A pneumatic tire includes a pair of bead portions, a pair of bead cores each disposed in a respective one of the pair of bead portions, a carcass extending between the pair of bead cores, the carcass including a carcass ply that includes a main portion extending between the pair of bead cores and a pair of turn-up portions each turned up around a respective one of the pair of bead cores from axially inside to outside of the tire and extending outwardly in a tire radial direction, and a reinforcing rubber layer disposed in each bead portion and being adjacent to an axially outside of the turn-up portion, wherein the reinforcing rubber layer has a laminated body in which a plurality of sheet-shaped rubber members having different radial lengths are laminated in the tire axial direction.

First claim

The invention claimed is:

1. A pneumatic tire comprising:
a pair of bead portions;
a pair of bead cores each disposed in a respective one of the pair of bead portions;
a carcass extending between the pair of bead cores, the carcass comprising a carcass ply that comprises a main portion extending between the pair of bead cores and a pair of turn-up portions each turned up around a respective one of the pair of bead cores from axially inside to outside of the tire and extending outwardly in a tire radial direction; and
a reinforcing rubber layer disposed in each bead portion and being adjacent to an axially outside of a respective one of the pair of turn-up portions, wherein
the reinforcing rubber layer has a laminated body in which a plurality of sheet-shaped rubber members having different radial lengths are laminated in the tire axial direction,
the plurality of sheet-shaped rubber members are rubber sheet members in which cords are not embedded,
the reinforcing rubber layer comprises a maximum thickness portion having a part where the plurality of sheet-shaped rubber members is laminated and a minimum thickness portion where the plurality of sheet-shaped rubber members is not laminated,
a difference (Ta−Tb) between a thickness Ta of the maximum thickness portion and a thickness Tb of the minimum thickness portion is equal to or more than 1 mm,
the minimum thickness portion forms an outer end portion in the tire radial direction of the reinforcing rubber layer,
the outer end portion has a length in the tire radial direction equal to or more than 3 mm,
in a normal state in which the tire is mounted to a normal rim and inflated to a normal inner pressure but loaded with no load, an outermost end in the tire radial direction of a contact position between the tire and the normal rim is located within the maximum thickness portion region of the reinforcing rubber layer in the tire radial direction,
each sheet-shaped rubber member has a maximum thickness equal to or less than 2.0 mm,
in each bead portion, a clinch rubber is disposed outwardly in the tire radial direction of the reinforcing rubber layer, and
a complex elastic modulus of the reinforcing rubber layer is equal to or more than two times a complex elastic modulus of the clinch rubber.

2. The pneumatic tire according to claim 1 , wherein a thickness of the reinforcing rubber layer decreases from a center region thereof in the tire radial direction toward both ends thereof.

3. The pneumatic tire according to claim 1 , wherein a ratio (Ta/Tb) of the thickness Ta to the thickness Tb is in a range from 1.5 to 2.5.

4. The pneumatic tire according to claim 1 , wherein the minimum thickness portion forms an inner end portion in the tire radial direction of the reinforcing rubber layer.

5. The pneumatic tire according to claim 1 , wherein the maximum thickness portion forms an inner end portion in the tire radial direction of the reinforcing rubber layer.

6. The pneumatic tire according to claim 1 , wherein the laminated body comprises a portion in which three or more of the sheet-shaped rubber members are laminated and a portion where two sheet-shaped rubber members are laminated.

7. The pneumatic tire according to claim 1 , wherein the maximum thickness portion comprises a portion extending in the tire radial direction with the thickness Ta that is constant.

8. The pneumatic tire according to claim 7 , wherein the minimum thickness portion comprises a portion extending in the tire radial direction with the thickness Tb that is constant.

9. The pneumatic tire according to claim 8 , wherein the minimum thickness portion forms an outer end portion and an inner portion in the tire radial direction of the reinforcing rubber layer.

10. The pneumatic tire according to claim 9 , wherein a length L 2 in the tire radial direction of the inner end portion formed by the minimum thickness portion is smaller than a length L 1 in the tire radial direction of the outer end portion formed by the minimum thickness portion.

11. The pneumatic tire according to claim 10 , wherein the length L 2 is equal to or less than 5 mm, and the length L 1 is equal to or less than 10 mm.

12. The pneumatic tire according to claim 1 , wherein the plurality of sheet-shaped rubber members is made of the same rubber material.

13. The pneumatic tire according to claim 1 , wherein
the plurality of sheet-shaped rubber members comprises an axial inner rubber member and an axial outer rubber member arranged outwardly in the tire axial direction of the axial inner rubber member,
the axial inner rubber member has an outer end in the tire radial direction located outwardly of an outer end in the tire radial direction of the axial outer rubber member, and
the axial inner rubber member has an inner end in the tire radial direction located inwardly of an inner end in the tire radial direction of the axial outer rubber member.

14. A pneumatic tire comprising:
a pair of bead portions;
a pair of bead cores each disposed in a respective one of the pair of bead portions;
a carcass extending between the pair of bead cores, the carcass comprising a carcass ply that comprises a main portion extending between the pair of bead cores and a pair of turn-up portions each turned up around a respective one of the pair of bead cores from axially inside to outside of the tire and extending outwardly in a tire radial direction to a radially outer end thereof; and
a reinforcing rubber layer disposed in each bead portion and being adjacent to an axially outside of a respective one of the pair of turn-up portions, wherein
the reinforcing rubber layer has a laminated body in which a plurality of sheet-shaped rubber members having different radial lengths are laminated in the tire axial direction,
the reinforcing rubber layer comprises a maximum thickness portion having a part where the plurality of sheet-shaped rubber members is laminated and a minimum thickness portion where the plurality of sheet-shaped rubber members is not laminated,
a difference (Ta−Tb) between a thickness Ta of the maximum thickness portion and a thickness Tb of the minimum thickness portion is equal to or more than 1 mm,
the minimum thickness portion forms an outer end portion in the tire radial direction of the reinforcing rubber layer,
the outer end portion has a length in the tire radial direction equal to or more than 3 mm,
a radially outermost end of the reinforcing rubber layer is located radially inwardly of a radially outermost end of the turn-up portions,
the plurality of sheet-shaped rubber members are rubber sheet members in which cords are not embedded, and
each sheet-shaped rubber member has a maximum thickness equal to or less than 2.0 mm.

15. The pneumatic tire according to claim 14 , wherein
the plurality of sheet-shaped rubber members comprises an axial inner rubber member and an axial outer rubber member arranged outwardly in the tire axial direction of the axial inner rubber member,
the axial inner rubber member has an outer end in the tire radial direction located outwardly of an outer end in the tire radial direction of the axial outer rubber member, and the axial inner rubber member has an inner end in the tire radial direction located inwardly of an inner end in the tire radial direction of the axial outer rubber member.

16. A pneumatic tire comprising:
a pair of bead portions;
a pair of bead cores each disposed in a respective one of the pair of bead portions;
a carcass extending between the pair of bead cores, the carcass comprising a carcass ply that comprises a main portion e

Assignees

• Sumitomo Rubber Ind

Inventors

• Ishigaki Yuichi
• Yao Masahiro
• Monji Mami

Classifications

• B60C2015/0621

  adjacent to the carcass turnup portion · CPC title

• B60C2015/0614

  characterised by features of the chafer or clinch portion, i.e. the part of the bead contacting the rim · CPC title

• B60C2015/061

  Dimensions of the bead filler in terms of numerical values or ratio in proportion to section height · CPC title

• B29D2030/486

  Additional components for the tyre bead areas, e.g. cushioning elements, chafers, flippers · CPC title

• B29D2030/482

  Applying fillers or apexes to bead cores · CPC title