PNEUMATIC RADIAL TIRE

• US 20100288414A1
• Filed: 09/21/2007
• Published: 11/18/2010
• Est. Priority Date: 09/22/2006
• Status: Abandoned Application

• Current Assignee: Yokohama Rubber Company Limited
• Original Assignee: Yokohama Rubber Company Limited
• Inventors: Ueda, Yoshio
• Application Number:
  US12/377,356
• Publication Number:
  US 20100288414A1
• Time in Patent Office: Days
• US Class Current: 152/527
• CPC Class Codes: B60C 9/2009 comprising plies of different materials

Abstract

An object of the present invention is to provide a pneumatic radial tire that achieves the characteristics of both an excellent effect of reducing road noises of an intermediate frequency (250 to 315 Hz) and an excellent high durability, without lowering the anti-separation performance of a belt cord in edges of belt layers, even in a case where a belt cover layer is composed of an high young'"'"'s modulus organic fiber cord. The pneumatic radial tire according to the present invention includes: at least two belt layers each composed of a steel cord and disposed on an outer periphery of a carcass layer; and a belt cover layer obtained by winding an organic fiber cord in a tire circumferential direction and disposed to cover at least an edge portion of the belt layers. In the pneumatic radial tire, each of the belt layers is composed of the steel cord with a (2+1) twist structure, and the belt cover layer is formed of a high young'"'"'s modulus organic fiber cord with young'"'"'s modulus of 4.5 to 18.0 GPa between tensile loads of 10 N to 99 N.

Claims

1. A pneumatic radial tire comprising:

at least two belt layers each composed of a steel cord and disposed on an outer periphery of a carcass layer; and

a belt cover layer obtained by winding an organic fiber cord in a tire circumferential direction and disposed to cover at least an edge portion of the belt layers, wherein

each of the belt layers is composed of the steel cord with a (2+1) twist structure, and

the belt cover layer is formed of a high young'"'"'s modulus organic fiber cord with young'"'"'s modulus of 4.5 to 18.0 GPa between tensile loads of 10 N to 99 N.

2. The pneumatic radial tire according to claim 1, wherein the high young'"'"'s modulus organic fiber cord is a cord made of any one of a polyethylene naphthalate fiber and a polyolefin ketone fiber.

3. The pneumatic radial tire according to claim 1, wherein the high young'"'"'s modulus organic fiber cord is a composite fiber cord made of at least two selected from the group consisting of a nylon 6 fiber, a nylon 66 fiber, a polyethylene terephthalate fiber, a polyethylene naphthalate fiber, a polyolefin ketone fiber, a polyvinyl alcohol fiber, an aramid fiber, and a rayon fiber.

4. The pneumatic radial tire according to claim 1, wherein

core wires of the steel cord with the (2+1) twist structure each are not twisted at all, or soft-twisted at a twist pitch of not less than 20 mm, and

a sheath wire thereof is twisted at a twist pitch of 10 to 30 mm.

5. The pneumatic radial tire according to claim 4, wherein diameters of the core wires and the sheath wire are 0.1 to 0.4 mm.

6. The pneumatic radial tire according to claim 1, wherein a length for which an outer end position, in a tire width direction, of the belt cover layer protrudes from a corresponding edge position of a belt layer having a maximum width among the belt layers is not less than 3 mm but not more than 30 mm.

7. The pneumatic radial tire according to claim 1, wherein

the belt cover layer is an edge cover, and

an inner end position, in the tire width direction, of the belt cover layer is located at a position displaced inward in the tire width direction for not less than 5 mm from an edge position of a belt layer having a minimum width among the belt layers.