Pneumatic tire

Patent metadata

Field	Value
Publication number	US-11097575-B2
Application number	US-201616064931-A
Country	US
Kind code	B2
Filing date	Dec 22, 2016
Priority date	Dec 25, 2015
Publication date	Aug 24, 2021
Grant date	Aug 24, 2021

Abstract

A pneumatic tire includes a bead portions and a bead core at the bead portions, the tire being mounted to a 15°-tapered specified rim. The bead portions include a portion inward in a radial direction of an extension line of an inner circumferential surface of the bead core, the extension line extending in the lateral direction, that is positioned outward in the tire lateral direction of an imaginary line passing through a first intersection point between the extension line and a tire inner surface and extends inward in the tire radial direction from the extension line at an angle perpendicular to the extension line. An angle α formed by the imaginary line and a line segment passing through a second intersection point between a bead base and the tire inner surface and the first intersection point between the extension line and the tire inner surface is from 0° to 25°.

First claim

The invention claimed is:

1. A pneumatic tire comprising:
a pair of bead portions disposed on both sides of a tire equatorial plane in a tire lateral direction; and
a bead core provided to each of the pair of bead portions and formed into a hexagonal shape as viewed in a tire meridian cross section;
the pneumatic tire being mounted to a 15°-tapered specified rim,
the pair of bead portions comprising a portion inward in a tire radial direction of an extension line of an inner circumferential surface of the hexagonal shape of the bead core, the extension line extending in the tire lateral direction, that is positioned outward in the tire lateral direction of an imaginary line that passes through an intersection point between the extension line and a tire inner surface and extends inward in the tire radial direction from the extension line at an angle perpendicular to the extension line,
an angle α formed by the imaginary line and a line segment passing through an intersection point between the tire inner surface and an engaging portion that serves as the inner circumferential surface of the pair of bead portions and engages with the specified rim and the intersection point between the extension line and the tire inner surface being from 10° to 25°,
an angle θ of the extension line with respect to a straight line perpendicular to the tire equatorial plane being 13° to 17°, and
an innermost vertex in the tire lateral direction of the hexagonal shape of the bead core is positioned inward in the tire lateral direction from an intersection point between the tire inner surface and the engaging portion.

2. The pneumatic tire according to claim 1 , wherein the pair of bead portions are provided such that an angle formed by the line segment and a straight line that passes through both end portions of the engaging portion in the tire lateral direction is from 85° to 100°.

3. The pneumatic tire according to claim 2 , wherein the engaging portion comprises a rubber layer having a complex elastic modulus from 3 MPa to 7 MPa, and an elongation at break from 200% to 350%.

4. The pneumatic tire according to claim 1 , wherein the engaging portion comprises a rubber layer having a complex elastic modulus from 3 MPa to 7 MPa, and an elongation at break from 200% to 350%.

5. The pneumatic tire according to claim 1 , wherein the angle α is from 15° to 25°.

6. The pneumatic tire according to claim 1 , wherein the angle α is from 20° to 25°.

7. The pneumatic tire according to claim 1 , wherein:
a carcass is turned back outward in the tire lateral direction along the bead core; and
a carcass reinforcing layer made from steel cord is disposed layered on an outer side of the carcass at a turned back portion of the carcass.

8. The pneumatic tire according to claim 1 , wherein a distance from a straight line passing through a bead toe and a bead heel of one bead portion to the extension line decreases from the bead toe to the bead heel.

9. A pneumatic tire comprising:
a pair of bead portions disposed on both sides of a tire equatorial plane in a tire lateral direction; and
a bead core provided to each of the pair of bead portions and formed into a hexagonal shape as viewed in a tire meridian cross section;
the pneumatic tire being mounted to a 15°-tapered specified rim,
the pair of bead portions comprising a portion inward in a tire radial direction of an extension line of an inner circumferential surface of the hexagonal shape of the bead core, the extension line extending in the tire lateral direction, that is positioned outward in the tire lateral direction of an imaginary line that passes through an intersection point between the extension line and a tire inner surface and extends inward in the tire radial direction from the extension line at an angle perpendicular to the extension line,
an angle α formed by the imaginary line and a line segment passing through an intersection point between the tire inner surface and an engaging portion that serves as the inner circumferential surface of the pair of bead portions and engages with the specified rim and the intersection point between the extension line and the tire inner surface being from 10° to 25°,
an angle θ of the extension line with respect to a straight line perpendicular to the tire equatorial plane being 13° to 17°,
a carcass being turned back outward in the tire lateral direction along the bead core, and
an axially innermost point in the tire lateral direction of the carcass that is radially inward of a maximum tire section width position being positioned in a region between the extension line of the inner circumferential surface of the hexagonal shape of the bead core and an extension line of the outer circumferential surface of the hexagonal shape of the bead core.

10. The pneumatic tire according to claim 9 , wherein an angle formed by a second line segment parallel to the tire lateral direction, intersecting a radially outermost point of the bead core, and a tangent line of the carcass at a second intersection point where the second line segment intersects the carcass is less than 75°.

Assignees

• Yokohama Rubber Co Ltd

Inventors

• Suzuki Takayuki

Classifications

• B60C15/024 Primary

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

• B60C15/00

  Tyre beads, e.g. ply turn-up or overlap · 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

• B60C15/0635

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

• B60C15/06

  Flipper strips, fillers, or chafing strips {and reinforcing layers for the construction of the bead} · CPC title