Heavy-duty pneumatic tire

Patent metadata

Field	Value
Publication number	US-10589577-B2
Application number	US-201615208758-A
Country	US
Kind code	B2
Filing date	Jul 13, 2016
Priority date	Jul 14, 2015
Publication date	Mar 17, 2020
Grant date	Mar 17, 2020

Abstract

A heavy-duty pneumatic tire includes a carcass ply including a main portion extending between bead cores and a pair of turn-up portions, a first reinforcing layer of a steel cord disposed in each bead portion in a U-shaped manner, and a second reinforcing layer of an organic fiber cord disposed in each bead portion and at least a part of the second reinforcing layer extending in a radial direction of the tire at an axially outward location of the first reinforcing layer. The second reinforcing layer includes an axially inner second ply and an outer second ply. The outer second ply has an inner end positioned below the bead core. The inner second ply has an inner end located axially inward of the inner end of the outer second ply, and has a substantially same length as the outer second ply in a tire cross-section.

First claim

What is claimed is:

1. A heavy-duty pneumatic tire comprising:
a tread portion;
a pair of sidewall portions;
a pair of bead portions each having a bead core therein, each bead core having a radially innermost end position thereof and an axially innermost end position thereof, each bead portion being provided with a bead apex rubber that extends radially outwardly from the bead core in a tapered manner and that includes an inner apex and an outer apex disposed radially outwardly of the inner apex;
a carcass comprising a carcass ply comprising a main portion extending between the bead cores and a pair of turn-up portions each wound up around the bead core from axially inside to the outside of the tire;
a first reinforcing layer of a steel cord disposed in each bead portion, the first reinforcing layer extending in a U-shaped manner to surround the bead core; and
a second reinforcing layer of an organic fiber cord disposed in each bead portion, at least a part of the second reinforcing layer extending in a radial direction of the tire at an axially outward location of the first reinforcing layer, the second reinforcing layer comprising an inner second ply being in contact with the first reinforcing layer and an outer second ply being in contact with the inner second ply,

wherein
the outer second ply has an inner end positioned below the bead core,
the inner second ply has an inner end located axially inward of the inner end of the outer second ply,
the inner end of the inner second ply is located radially outward of the radially innermost end position of the bead core and located radially inward of the axially innermost end position of the bead core,
the inner second ply has substantially the same length as the outer second ply in a tire cross-section,
in each bead portion, the inner apex has a substantially triangular cross-section extending from the bead core to a radially outer end thereof which is located radially outward of a radially outer end of the turn-up portion,
the inner apex has a complex modulus E*1 of from 40 to 65 MPa,
the outer apex is superimposed on the inner apex through a boundary extending radially inwardly from the radially outer end of the inner apex to the turn-up portion, and
the outer apex has a complex modulus E*2 in a range of from 3 to 5 MPa.

2. The heavy-duty pneumatic tire according to claim 1 , wherein
at least one of the bead cores comprises a substantially hexagonal cross-sectional shape having a radially inner surface, and
an angle between the inner surface of the bead core and a rim seat is zero plus/minus 3 degrees under both a standard condition and a loaded condition,
wherein the standard condition is such that the tire is mounted on a standard wheel rim with a standard pressure and is loaded with no tire load, and wherein the loaded condition is such that the tire under the standard condition is grounded with a standard tire load at a camber angle of zero.

3. The heavy-duty pneumatic tire according to claim 1 , wherein
the organic fiber cord of the inner second ply is oriented at an angle of from 55 to 75 degrees with respect to a radial direction of the tire, and
the organic fiber cord of the outer second ply is oriented at an angle of from 55 to 75 degrees with respect to the radial direction of the tire in an opposite direction to the inner second ply.

4. The heavy-duty pneumatic tire according to claim 1 , wherein
the inner second ply comprises an outer end located radially outward of a radially outer end of the turn-up portion in each bead portion, and
a distance between the outer end of the inner second ply and the outer end of the turn-up portion is in a range of from 8 to 18 mm in a radial direction.

5. The heavy-duty pneumatic tire according to claim 1 , wherein a distance between an outer end of the inner second ply and an outer end of the outer second ply is in a range of from 8 to 18 mm in a radial direction.

6. The heavy-duty pneumatic tire according to claim 1 , wherein a radial height of an outer end of the outer second ply from a bead base line is in a range of from 25% to 40% of a radial height of the carcass from the bead base line.

7. The heavy-duty pneumatic tire according to claim 1 , each bead portion further comprising a chafer rubber, wherein
the chafer rubber is disposed axially outward of the second reinforcing layer and extends radially inwardly of the bead core so that the chafer rubber is configured to be in contact with a rim seat when the tire is mounted on a rim,
the chafer rubber has a radially outer end which is located radially outward of a radially outer end of the outer second ply,
the chafer rubber has a minimum thickness of at an axially outer region of the bead core in a range of from 2.5 to 6.0 mm, and
the chafer rubber has a complex modulus E*3 in a range of from 7 to 14 MPa.

8. The heavy-duty pneumatic tire according to claim 1 , wherein the inner second ply has the same length as the outer second ply in a tire cross-section.

9. The heavy-duty pneumatic tire according to claim 1 ,
wherein the inner end of the outer second ply is located between the radially innermost end position of the bead core and the axially innermost end position of the bead core in the tire axial direction, and
wherein the inner end of the outer second ply is located nearer to the radially innermost end position of the bead core than the axially innermost end position of the bead core in the tire axial direction.

10. A heavy-duty pneumatic tire comprising:
a tread portion;
a pair of sidewall portions;
a pair of bead portions each having a bead core therein, each bead core having a radially innermost end position thereof and an axially innermost end position thereof;
a carcass comprising a carcass ply comprising a main portion extending between the bead cores and a pair of turn-up portions each wound up around the bead core from axially inside to the outside of the tire;
a first reinforcing layer of a steel cord disposed in each bead portion, the first reinforcing layer extending in a U-shaped manner to surround the bead core; and
a second reinforcing layer of an organic fiber cord disposed in each bead portion, at least a part of the second reinforcing layer extending in a radial direction of the tire at an axially outward location of the first reinforcing layer, the second reinforcing layer comprising an inner second ply being in contact with the first reinforcing layer and an outer second ply being in contact with the inner second ply,

wherein
the outer second ply has an inner end positioned below the bead core,
the inner second ply has an inner end located axially inward of the inner end of the outer second ply,
the inner end of the inner second ply is located radially outward of the radially innermost end position of the bead core and located radially inward of the axially innermost end position of the bead core,
the inner second ply has substantially the same length as the outer second ply in a tire cross-section;
a chafer rubber disposed in each bead portion, wherein
the chafer rubber is disposed axially outward of the second reinforcing layer and extends radially inwardly of the bead core so that the chafer rubber is configured to be in contact with a rim seat when the tire is mounted on a rim,
the chafer rubber has a radially outer end which is located radially outward of a radially outer end of the outer second ply,
the chafer rubber has a minimum thickness of at an axially outer region of the bead core in a range of from 2.5 to 6.0 mm, and
the chafer rubber has a complex modulus E*3 in a range of from 7 to 14 MPa.

11. The heavy-duty pneumatic tire according to

Assignees

• Sumitomo Rubber Ind

Inventors

• Tanaka Kaori

Classifications

• B60C2015/0664

  comprising cords at an angle of 30 to 60 degrees to the circumferential direction · CPC title

• B60C15/0653

  with particular configuration of the cords in the respective bead reinforcing layer · CPC title

• B60C2015/0667

  comprising cords at an angle of 60 to 90 degrees to the circumferential direction · CPC title

• B60C2015/009

  Height of the carcass terminal portion defined in terms of a numerical value or ratio in proportion to section height · CPC title

• B60C2015/066

  comprising cords at an angle of 10 to 30 degrees to the circumferential direction · CPC title