Heavy-duty pneumatic tire
AssigneeSumitomo Rubber Industries, Ltd.
InventorQingmao Li
Life of this patent
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Abstract
Provided is a heavy-duty pneumatic tire in which not only occurrence of a damage of CBU but also occurrence of pulling-out of a carcass ply can be inhibited, and which has excellent durability. In the tire, beads each include a cover enclosing at least a part of a core. The cover is located, between the core and the carcass ply, in a portion at which the carcass ply encloses the core. The cover is composed of one cover ply including a large number of aligned cover cords and a cover topping rubber covering the cover cords. A ratio of a distance between the cover cords to an outer diameter of a carcass cord is not lower than 0.35 and not higher than 0.85. A difference between a hardness of the cover topping rubber and a hardness of a carcass topping rubber is not less than −5 and not greater than 5.
Claims12
A heavy-duty pneumatic tire comprising:
- a pair of beads;
- a pair of chafers, each of the chafers is disposed axially outward of a corresponding one of the beads;
- and
- a carcass extending on and between one of the beads and another bead, wherein
- each bead includes a core, an apex located radially outward of the core, and a cover enclosing at least a part of the core,
- the apex includes an inner apex and an outer apex,
- the carcass includes a carcass ply including a plurality of aligned carcass cords and further including a carcass topping rubber covering the carcass cords,
- each carcass cord is a steel cord,
- the carcass ply is turned up around the core from an inner side to an outer side in an axial direction,
- the cover is located, between the core and the carcass ply, in a portion at which the carcass ply encloses the core,
- the cover is composed of one cover ply including a plurality of aligned cover cords and further including a cover topping rubber covering the cover cords,
- each cover cord is a cord formed from an organic fiber,
- a ratio of a distance between the cover cords to an outer diameter of each carcass cord is not lower than 0.35 and not higher than 0.85, wherein the outer diameter of each carcass cord is in a range of 0.85 mm to 1.5 mm,
- a difference between a hardness of the cover topping rubber and a hardness of the carcass topping rubber is not less than −5 and not greater than 5,
- a hardness of each of the chafers is equal to or higher than the hardness of the carcass topping rubber,
- the hardness of the cover topping rubber is lower than the hardness of the carcass topping rubber,
- wherein a difference between the hardness of each of the chafers and the hardness of the carcass topping rubber is not less than 1 and not greater than 10,
- each of the chafers is softer than the inner apex,
- each of the chafers is harder than the outer apex,
- the carcass ply that is turned up around the core forms a turned-up portion of the carcass ply, and
- a ratio of a height of the turned-up portion to a height of a cross section of the carcass is not lower than 0.15 and not higher than 0.25.
Dependencies are inferred from the claim text.