Pneumatic tire

Patent metadata

Field	Value
Publication number	US-11999200-B2
Application number	US-201917284624-A
Country	US
Kind code	B2
Filing date	Oct 7, 2019
Priority date	Nov 2, 2018
Publication date	Jun 4, 2024
Grant date	Jun 4, 2024

Abstract

In a pneumatic tire, a bead filler is radially outward of a bead core, a carcass turned up end is radially inward of an outer side end of the bead filler, the turned up end is spaced from a carcass body, a reinforcement layer is laterally outward of the bead filler, a sidewall rubber extends from a sidewall to the bead, an inner rubber reinforcing layer is between the bead filler and the reinforcement layer and adjacent to the turned up end, a crack suppression layer is between the reinforcement layer and the sidewall rubber, the crack suppression layer extends 5 mm or more from where the crack suppression layer overlaps, the reinforcement layer contacts the carcass body radially outwardly of the bead filler, and a 100% modulus Kc M100 of the crack suppression layer is at least 1.5 times that of the sidewall rubber.

First claim

The invention claimed is:

1. A pneumatic tire, comprising:
a tread portion extending in a tire circumferential direction and having an annular shape;
a pair of sidewall portions respectively disposed on both sides of the tread portion;
a pair of bead portions each disposed on an inner side in a tire radial direction of the sidewall portions; and
a carcass layer mounted between the pair of bead portions and comprising a plurality of steel cords, the carcass layer being turned up around a bead core of each of the bead portions from a tire inner side to a tire outer side,
a bead filler being disposed on an outer circumference of the bead core of each of the bead portions, a turned up end portion of the carcass layer being disposed on a radially inner side with respect to a radially outer side end portion of the bead filler, the turned up end portion of the carcass layer being spaced apart from a body portion of the carcass layer, at least one organic fiber reinforced layer that comprises a plurality of organic fiber cords being disposed on an outer side in a width direction of the bead filler in each of the bead portions, and a sidewall rubber layer exposed on a tire outer surface being disposed from the sidewall portion to the bead portion, and
an inner rubber reinforcing layer being disposed between the bead filler and the organic fiber reinforced layer and adjacent to the turned up end portion of the carcass layer, a crack suppression layer being disposed between the organic fiber reinforced layer and the sidewall rubber layer, the crack suppression layer extending toward a radially outer side from a position where the crack suppression layer overlaps, by 5 mm or more, the organic fiber reinforced layer located on an outermost side in the tire width direction and contacting the body portion of the carcass layer at a position on a radially outer side with respect to the radially outer side end portion of the bead filler, and a 100% modulus KcM100 of the crack suppression layer being at least 1.5 times as large as a 100% modulus SM100 of the sidewall rubber layer, wherein
the inner rubber reinforcing layer contacts the body portion of the carcass layer at a position on the radially outer side with respect to the radially outer side end portion of the bead filler, the inner rubber reinforcing layer has a 100% modulus KiM100 of from 4.5 MPa to 10.0 MPa, and the inner rubber reinforcing layer has an elongation at break KiEB of 300% or more.

2. The pneumatic tire according to claim 1 , wherein the 100% modulus KcM100 of the crack suppression layer ranges from 4.5 MPa to 10.0 MPa.

3. The pneumatic tire according to claim 1 , wherein the crack suppression layer has an elongation at break KcEB of 300% or more.

4. The pneumatic tire according to claim 1 , wherein the crack suppression layer has a thickness TKC of from 2.0 mm to 6.0 mm in a region from the radially outermost end portion of the organic fiber reinforced layer to a position where the crack suppression layer contacts the body portion of the carcass layer.

5. The pneumatic tire according to claim 1 , wherein in a tire meridian cross-section, in a region with a radius of 15 mm or less around the radially outermost end portion of the organic fiber reinforced layer, a maximum value Tmax and a minimum value Tmin of a total thickness of the crack suppression layer and the sidewall rubber layer satisfy a relationship 1.00≤Tmax/Tmin≤1.25.

6. The pneumatic tire according to claim 1 , wherein the inner rubber reinforcing layer has a thickness Tc of 2.0 mm or more at the turned up end portion of the carcass layer, and the inner rubber reinforcing layer has a thickness TN of 1.5 mm or more at the radially outermost end portion of the organic fiber reinforced layer.

7. The pneumatic tire according to claim 1 , wherein the organic fiber reinforced layer has a cord inclination angle β of from 15° to 45° with respect to the tire circumferential direction at the radially outer side end portion.

8. The pneumatic tire according to claim 1 , wherein the organic fiber reinforced layer has a tensile rigidity AN of from 15 kN/50 mm to 50 kN/50 mm.

9. The pneumatic tire according to claim 1 , wherein the organic fiber reinforced layer has a cord count NN of from 25 cords/50 mm to 45 cords/50 mm.

10. The pneumatic tire according to claim 1 , wherein the at least one organic fiber reinforced layer comprises at least two organic fiber reinforced layers in which the organic fiber cords intersect one another, and a step width WN between end portions of the at least two organic fiber reinforced layers is 5 mm or more.

11. The pneumatic tire according to claim 1 , wherein a distance Ph from a center of the bead core to the turned up end portion of the carcass layer ranges from 26.0 mm to 40.0 mm, a shortest distance TBF from the turned up end portion of the carcass layer to the body portion of the carcass layer is 11.0 mm or more, and a shortest distance TR from the organic fiber reinforced layer to an outer surface of the bead portion at a position of the turned up end portion of the carcass layer ranges from 6.0 mm to 12.0 mm.

12. The pneumatic tire according to claim 1 , wherein a steel reinforced layer comprising a plurality of steel cords is disposed in each of the bead portions in such a manner as to wrap around the carcass layer, the bead core, and the bead filler, and a distance Ph from the center of the bead core to the turned up end portion of the carcass layer and a distance Sho from the center of the bead core to the end portion of the steel reinforced layer satisfy a relationship 5.0 mm≤Ph-Sho.

13. The pneumatic tire according to claim 1 , wherein the bead filler comprises a hard filler layer located on the radially inner side and a soft filler layer located on the radially outer side, the hard filler layer has a 100% modulus B1M100 of from 6.0 MPa to 18.0 MPa, and the soft filler layer has a 100% modulus B2M100 of from 1.0 MPa to 6.0 MPa.

14. The pneumatic tire according to claim 1 , comprising a load index of 121 or more on a single wheel, or a ply rating of 10 PR or more.

Assignees

• Yokohama Rubber Co Ltd

Inventors

• Nishio Koji

Classifications

• B60C15/0635 Primary

  using chippers between the carcass layer and chafer rubber wrapped around the bead · CPC title

• B60C15/0009

  features of the carcass terminal portion · CPC title

• B60C15/0603

  characterised by features of the bead filler or apex · CPC title

• B60C15/0628

  comprising a bead reinforcing layer · CPC title

• B60C2015/0621

  adjacent to the carcass turnup portion · CPC title