Pneumatic tire

Patent metadata

Field	Value
Publication number	US-11400768-B2
Application number	US-201616065015-A
Country	US
Kind code	B2
Filing date	Dec 22, 2016
Priority date	Dec 25, 2015
Publication date	Aug 2, 2022
Grant date	Aug 2, 2022

Abstract

A pneumatic tire mountable on a 15° tapered specified rim, the pneumatic tire including a bead portion, bead core, a carcass, a steel cord reinforcing layer, and a bead rubber layer. A distance from a second line segment to a third line segment is from 4 mm to 8 mm, and a ratio R 2 /R 1 is from 0.935 to 0.975, wherein R 2 is a tire radius at a bead toe of a bead base portion and R 1 is a tire radius at a bead heel.

First claim

The invention claimed is:

1. A pneumatic tire mountable on a 15° tapered specified rim, the pneumatic tire comprising:
a pair of bead portions disposed on either side of a tire equatorial plane in a tire lateral direction;
a bead core provided in each of the pair of bead portions, the bead core having a hexagonal shape when viewed in a meridian cross-section;
a carcass supported by the bead core provided in each of the pair of bead portions, the carcass comprising a carcass body portion and a carcass folded back portion formed by the carcass folding back at the bead core;
a steel cord reinforcing layer disposed on an outer surface of the carcass folded back at the bead core; and
a bead rubber layer with at least a portion thereof disposed between the carcass body portion and the carcass folded back portion;
when the pneumatic tire is not mounted on the specified rim,
a distance from a second line segment to a third line segment being from 4 mm to 8 mm,
wherein a first line segment passing through an outermost projecting point of the bead core in the tire lateral direction and being parallel with a longest side of the bead core, a side of a bead base portion closer to a bead heel that is a portion of the bead portion that comes into contact with the specified rim, a curved line of a tire outer surface that is a portion of the bead portion that is located outward from the bead base portion in the tire lateral direction, a first intersection point of the side and the curved line, the second line segment passing through the first intersection point and being perpendicular to the first line segment, and the third line segment passing through the outermost projecting point and being perpendicular to the first line segment are specified,
a ratio R 2 /R 1 being from 0.935 to 0.975, wherein R 2 is a tire radius at a bead toe of the bead base portion, and R 1 is a tire radius at the bead heel, and
a ratio R 1 /R 3 is from 0.985 to 0.995, wherein R 3 is a tire radius at the bead core and R 1 is the tire radius at the bead heel,
wherein the bead base portion comprises an outer portion comprising the bead heel and an inner portion comprising the bead toe, and
an angle of a side of the outer portion with respect to a line perpendicular to the tire equatorial plane is from 18° to 23°, an angle of a side of the inner portion being from 27° to 33°.

Assignees

• Yokohama Rubber Co Ltd

Inventors

• Suzuki Takayuki

Classifications

• B60C15/0635

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

• B60C15/0072

  with ply reverse folding, i.e. carcass layer folded around the bead core from the outside to the inside · CPC title

• B60C9/0292

  Carcass ply curvature (sidewall curvature B60C13/003) · CPC title

• B60C15/04

  Bead cores · CPC title

• B60C15/024 Primary

  Bead contour, e.g. lips, grooves, or ribs · CPC title