Pneumatic tire

Patent metadata

Field	Value
Publication number	US-11260702-B2
Application number	US-201816768625-A
Country	US
Kind code	B2
Filing date	Nov 19, 2018
Priority date	Nov 30, 2017
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

In a cross-section of a pneumatic tire, a contour of the bead core is a polygon formed by tangent lines of circumferential portions of a bead wire, the contour includes a vertex with an acute angle and a bottom side opposite the vertex, the carcass layer is folded back along a circumference of the bead core in a bead portion, a folded back portion of the carcass layer from an outer end of the bead core extends in the radial direction, and a distance in the radial direction between a center of an arc profile of a tire outer surface and a straight line extending in the lateral direction through the vertex is within 20% of a radius r of the arc, and a distance in the lateral direction between the center of the arc and a straight line extending in the radial direction through the vertex is within 2r±0.4r.

First claim

The invention claimed is:

1. A pneumatic tire, comprising:
a tread portion with an annular shape that extends in a tire circumferential direction;
a pair of sidewall portions disposed on either side of the tread portion;
a pair of bead portions disposed toward the inside of the sidewall portions in a tire radial direction;
a bead core disposed in each one of the pair of bead portions;
a carcass layer mounted between the pair of bead portions; and
a side reinforcing layer having a crescent-shaped cross-section disposed toward the inside in a tire lateral direction of the carcass layer at each one of the pair of sidewall portions, wherein
the bead core comprises at least one bead wire wound in the tire circumferential direction,
in a meridian cross-section, a plurality of circumferential portions of the bead wire form at least one row in line in the tire lateral direction and a plurality of layers layered in the tire radial direction,
in a meridian cross-section, an external contour shape of the bead core is a polygon formed by common tangent lines of the circumferential portions of the bead wire, the external contour shape comprises a single vertex located toward the outside in the tire radial direction,
an internal angle θ 1 formed by two sides sandwiching the vertex is an acute angle, and the external contour shape comprises a bottom side located toward the inside in the tire radial direction at a position opposite the vertex and extending in the tire lateral direction,
the carcass layer comprises a body portion that extends from the tread portion, through a sidewall portion of the pair of sidewall portions, to a bead portion of the pair of bead portions, and a folded back portion that is bent and folded back along a circumference of the bead core in each one of the bead portions and extends from a position of an outer end of the bead core in the tire radial direction toward one of the pair of sidewall portions in contact with the body portion, and
a straight line extending in the tire lateral direction through the vertex is defined as a straight line L 1 , a straight line extending in the tire radial direction through the vertex is defined as a straight line L 2 , an arc constituting a profile of a portion of a tire outer surface located on an extension line of the straight line L 1 is defined as an arc, a distance in the tire radial direction between a center of the arc and the straight line L 1 is within 20% of a radius r of the arc, and a distance in the tire lateral direction between the center of the arc and the straight line L 2 with respect to the radius r of the arc is within a range of 2r±0.4r.

2. The pneumatic tire according to claim 1 , wherein at least a portion of the bead wire is packed in layers.

3. The pneumatic tire according to claim 1 , wherein
an extension line of an inner side in the tire lateral direction of the two sides sandwiching the vertex is defined as an extension line L 3 , an extension line of a portion of the carcass layer in a region between an auxiliary line a 1 and an auxiliary line a 2 is defined as an extension line L 4 , where the auxiliary line a 1 passes through the center of the arc and forms a 60° angle with the straight line L 1 and the auxiliary line a 2 passes through the center of the arc and forms a 10° angle with the straight line L 1 ,
the extension line L 4 is inclined further toward the outside in the tire lateral direction than the extension line L 3 , and an angle α 1 formed by the extension line L 3 and the extension line L 4 is from 0° to 20°.

4. The pneumatic tire according to claim 1 , wherein
an extension line of a portion of the carcass layer in a region between an auxiliary line a 1 and an auxiliary line a 2 is defined as an extension line L 4 , where the auxiliary line a 1 passes through the center of the arc and forms a 60° angle with the straight line L 1 and the auxiliary line a 2 passes through the center of the arc and forms a 10° angle with the straight line L 1 ,
an extension line of an outer side in the tire lateral direction of the two sides sandwiching the vertex is defined as an extension line L 5 , and
the internal angle θ 1 formed by the two sides sandwiching the vertex and an angle α 2 formed by the extension line L 4 and the extension line L 5 satisfy a relationship 0.30≤θ 1 /α 2 ≤1.0.

5. The pneumatic tire according to claim 1 , wherein
a folded back portion of the carcass layer contacting the bead core terminates in a region between an auxiliary line a 1 and an auxiliary line a 2 , where the auxiliary line a 1 passes through the center of the arc and forms a 60° angle with the straight line L 1 and the auxiliary line a 2 passes through the center of the arc and forms a 10° angle with the straight line L 1 .

6. The pneumatic tire according to claim 1 , wherein
an inner end portion in the tire lateral direction of the side reinforcing layer is located in a region between an auxiliary line a 1 and an auxiliary line a 2 , where the auxiliary line a 1 passes through the center of the arc and forms a 60° angle with the straight line L 1 and the auxiliary line a 2 passes through the center of the arc and forms a 10° angle with the straight line L 1 .

7. The pneumatic tire according to claim 2 , wherein
an extension line of an inner side in the tire lateral direction of the two sides sandwiching the vertex is defined as an extension line L 3 , an extension line of a portion of the carcass layer in a region between an auxiliary line a 1 and an auxiliary line a 2 is defined as an extension line L 4 , where the auxiliary line a 1 passes through the center of the arc and forms a 60° angle with the straight line L 1 and the auxiliary line a 2 passes through the center of the arc and forms a 10° angle with the straight line L 1 ,
the extension line L 4 is inclined further toward the outside in the tire lateral direction than the extension line L 3 , and an angle α 1 formed by the extension line L 3 and the extension line L 4 is from 0° to 20°.

8. The pneumatic tire according to claim 7 , wherein
an extension line of a portion of the carcass layer in a region between an auxiliary line a 1 and an auxiliary line a 2 is defined as an extension line L 4 , where the auxiliary line a 1 passes through the center of the arc and forms a 60° angle with the straight line L 1 and the auxiliary line a 2 passes through the center of the arc and forms a 10° angle with the straight line L 1 ,
an extension line of an outer side in the tire lateral direction of the two sides sandwiching the vertex is defined as an extension line L 5 , and
the internal angle θ 1 formed by the two sides sandwiching the vertex and an angle α 2 formed by the extension line L 4 and the extension line L 5 satisfy a relationship 0.30≤θ 1 /α 2 ≤1.0.

9. The pneumatic tire according to claim 8 , wherein
a folded back portion of the carcass layer contacting the bead core terminates in a region between an auxiliary line a 1 and an auxiliary line a 2 , where the auxiliary line a 1 passes through the center of the arc and forms a 60° angle with the straight line L 1 and the auxiliary line a 2 passes through the center of the arc and forms a 10° angle with the straight line L 1 .

10. The pneumatic tire according to claim 9 , wherein an inner end portion in the tire lateral direction of the side reinforcing layer is located in a region between an auxiliary line a 1 and an auxiliary line a 2 , where the auxiliary line a 1 passes through the center of the arc and forms a 60° angle with the straight line L 1 and the auxiliary line a 2 passes through the center of the arc and forms a 10° angle with the straight line L 1 .

Assignees

• Yokohama Rubber Co Ltd

Inventors

• Sasaya Yuki
• Nagayasu Masaaki
• Takemori Ryohei
• Tanno Atsushi
• Kouda Hiraku
• Matsuda Jun

Classifications

• B60C2015/048

  Polygonal cores characterised by the winding sequence · CPC title

• B60C15/0036 Primary

  with high ply turn-up, i.e. folded around the bead core and terminating radially above the point of maximum section width · CPC title

• B60C15/04 Primary

  Bead cores · CPC title

• B60C2015/044

  characterised by a wrapping layer · CPC title

• B60C2015/046

  Cable cores, i.e. cores made-up of twisted wires · CPC title