Pneumatic radial tire

Patent metadata

Field	Value
Publication number	US-9333805-B2
Application number	US-201113992812-A
Country	US
Kind code	B2
Filing date	Dec 19, 2011
Priority date	Dec 21, 2010
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

A pneumatic radial tire including a carcass composed of at least one carcass layer extending toroidally between a left-and-right pair of bead cores; a tread portion which is arranged on the outside in the tire radial direction of a crown region of the carcass to form a ground contacting portion; and a belt composed of two belt layers which is arranged between the tread portion and the crown region of the carcass to form a reinforcing portion. A reinforcing material constituting the belt layer is a bundle formed by arranging two cords in pairs; and, letting the diameter of a filament constituting the cord a (mm), the interval between the adjacent bundles as an expected value is increased by a/4 (mm) or larger compared to the interval represented by using the circumcircle of the cord.

First claim

The invention claimed is:

1. A pneumatic radial tire comprising:
a carcass composed of at least one carcass layer extending toroidally between a left-and-right pair of bead cores;
a tread portion which is arranged on the outside in the tire radial direction of a crown region of the carcass to form a ground contacting portion; and
a belt composed of at least two belt layers which is arranged between the tread portion and the crown region of the carcass to form a reinforcing portion, wherein
a reinforcing material constituting the belt layer is a bundle formed by arranging two cords without twisting them; each of the cords has a (1×2) structure consisting of two filaments, wherein the diameters of all filaments constituting the cord are the same, and, the diameter of each of the filaments being a (mm), an expected value of increment in bundle interval between adjacent bundles is a/4 (mm) or more greater than the interval between the adjacent bundles represented by using the circumcircle of the cord.

2. The pneumatic radial tire according to claim 1 , wherein the thickness of the belt layer is larger than 0.70 mm and smaller than 1.20 mm.

3. The pneumatic radial tire according to claim 1 , wherein the filament diameter is from 0.23 to 0.30 mm.

4. The pneumatic radial tire according to claim 1 , wherein the expected value of increment in bundle interval between the adjacent bundles at the first location is 4a/11 (mm) or more greater than the interval between the adjacent bundles represented by using the circumcircle of the cord.

Assignees

• Nakamura Keisuke
• Bridgestone Corp

Inventors

• Nakamura Keisuke

Classifications

• B60C9/2006

  consisting of steel cord plies only · CPC title

• B60C2009/2077

  Diameters of the cords; Linear density thereof · CPC title

• B60C9/20

  built-up from rubberised plies each having all cords arranged substantially parallel · CPC title

• B60C9/0007 Primary

  Reinforcements made of metallic elements, e.g. cords, yarns, filaments or fibres made from metal · CPC title

• B60C9/28 Primary

  characterised by the belt or breaker dimensions or curvature relative to carcass (B60C9/30 takes precedence) · CPC title