Heavy-duty pneumatic tire

Patent metadata

Field	Value
Publication number	US-11148477-B2
Application number	US-201816169658-A
Country	US
Kind code	B2
Filing date	Oct 24, 2018
Priority date	Nov 14, 2017
Publication date	Oct 19, 2021
Grant date	Oct 19, 2021

Abstract

A heavy-duty pneumatic tire includes a section width being equal to or less than 335 mm, an aspect ratio being equal to or less than 55%, and a toroidal carcass extending between axially spaced bead portions through a tread portion and sidewall portions, wherein the carcass includes a carcass ply which includes a main portion and a turn-up portion, a belt layer disposed radially outward of the carcass in the tread portion, a sidewall rubber defining an outer sidewall profile of each sidewall portion, and a chafer rubber defining an outer bead profile of each bead portion, wherein in each bead portion, on a straight line that is perpendicular to the main portion of the carcass ply and passes a radially inner end of the sidewall rubber, the chafer rubber has a thickness of from 40% to 60% of a thickness of the bead portion.

First claim

What is claimed is:

1. A heavy-duty pneumatic tire comprising:
a section width being equal to or less than 335 mm;
an aspect ratio being equal to or less than 55%;
a toroidal carcass extending between axially spaced bead portions through a tread portion and sidewall portions, wherein the carcass comprises a carcass ply comprising a main portion extending between bead cores each disposed in a respective one of the bead portions through the tread portion and the sidewall portions, and a turn-up portion turned up around each bead core of each bead portion from axially inside of the tire to outside of the tire and extending to a radially outer end thereof;
a belt layer disposed radially outward of the carcass in the tread portion, wherein the radially outer end of the turn-up portion is located between the main portion and the belt layer in the tread portion, wherein
the belt layer comprises first, second, third and fourth belt plies superimposed in this order from radially inside of the tire,
the second belt ply comprises an axially outer edge that is located axially outwardly of an axially outer edge of the first belt ply, in a tire half cross-section with respect to a tire equator;

a sidewall rubber defining an outer sidewall profile of each sidewall portion, the sidewall rubber having complex modulus E*4 of from 3.0 to 5.5 MPa; and
a chafer rubber defining an outer bead profile of each bead portion, wherein in each bead portion, on a straight line that is perpendicular to the main portion of the carcass ply and passes a radially inner end of the sidewall rubber, the chafer rubber has a thickness of from 40% to 60% of a thickness of the bead portion, wherein
in the tire half cross-section, the radially outer end of the turn-up portion of the carcass ply, in the tire axial direction, is located between the axially outer edges of the first belt ply and the second belt ply.

2. The heavy-duty pneumatic tire according to claim 1 , wherein the chafer rubber has complex modulus of from 10 to 15 MPa.

3. The heavy-duty pneumatic tire according to claim 1 , wherein
the chafer rubber comprises a bead toe portion located radially innermost of the tire, a bead base portion extending axially outwardly from the bead toe, and a bead heel portion located axially outermost of the bead base portion,
each bead core has a bead core reference position which is located radially innermost thereof, and
in each bead portion, an axial distance between the bead toe portion and the bead core reference position is in a range of from 30% to 40% of an axial distance between the bead toe portion and the bead heel portion.

4. The heavy-duty pneumatic tire according to claim 1 , wherein the carcass ply comprises steel cords having a cord diameter of from 0.6 to 0.8 mm.

5. The heavy-duty pneumatic tire according to claim 4 , wherein the steel cords are arranged so as to have from 20 to 30 ends per 50 mm width of the carcass ply.

6. The heavy-duty pneumatic tire according to claim 1 , further comprising
a cushion rubber disposed between the main portion of the carcass ply and each edge of the belt layer, wherein
the cushion rubber extends to a radially inner end thereof located radially inwardly of the radially outer end of the turn-up portion.

7. The heavy-duty pneumatic tire according to claim 6 , further comprising
a tapered bead apex rubber in each bead portion,

wherein
the bead apex rubber extends radially outwardly from the bead core to a radially outer end thereof between the main portion and the turn-up portion, and
in each bead portion, a radial distance between the radially inner end of the cushion rubber and the radially outer end of the bead apex rubber is in a range of from 25% to 35% of a product of the section width and the aspect ratio.

8. The heavy-duty pneumatic tire according to claim 7 , wherein in each bead portion, the radially outer end of the bead apex rubber is located radially outwardly of the straight line.

9. The heavy-duty pneumatic tire according to claim 8 , wherein
the chafer rubber has complex modulus E*6 of from 10 to 15 MPa and a radially outer end, and
in each bead portion, the radially outer end of the bead apex rubber is located radially inwardly of the radially outer end of the chafer rubber.

10. The heavy-duty pneumatic tire according to claim 1 , wherein the radially outer end of the sidewall rubber is located radially outwardly of the axially outer end of the second belt ply and radially inwardly of an axially outermost edge of the tread portion.

11. The heavy-duty pneumatic tire according to claim 9 , wherein the radially outer end of the sidewall rubber is located radially outwardly of the axially outer end of the second belt ply and radially inwardly of an axially outermost edge of the tread portion.

12. The heavy-duty pneumatic tire according to claim 1 , wherein a boundary line between the sidewall rubber and the chafer rubber has an arc shaped protruding radially inwardly.

13. The heavy-duty pneumatic tire according to claim 9 , wherein a boundary line between the sidewall rubber and the chafer rubber has an arc shaped protruding radially inwardly.

14. The heavy-duty pneumatic tire according to claim 10 , wherein a boundary line between the sidewall rubber and the chafer rubber has an arc shaped protruding radially inwardly.

15. The heavy-duty pneumatic tire according to claim 14 , wherein the outer end of the sidewall rubber is exposed at an axially outer surface of one of the sidewall portions.

Assignees

• Sumitomo Rubber Ind

Inventors

• Kanaya Yoshiki

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

• B60C2009/0425

  Diameters of the cords; Linear density thereof · CPC title

• B60C15/0045 Primary

  with ply turn-up up to the belt edges, i.e. folded around the bead core and extending to the belt edges · CPC title

• B60C2009/0223

  comprising a cushion layer between adjacent carcass plies · CPC title