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Heavy-duty pneumatic tire

A technology for pneumatic tires and beads, which is applied to heavy-duty tires, reinforcement layers of pneumatic tires, tire parts, etc., and can solve the problems of fretting wear, damage, and rupture of the core and carcass cords. Achieve excellent durability, inhibit damage, and inhibit the effects of pulling out

Pending Publication Date: 2021-03-12
SUMITOMO RUBBER IND LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, there is a possibility of fretting wear between the core and the carcass cord, resulting in damage accompanied by breakage of the carcass cord (Cord Broken Up: CBU).

Method used

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  • Heavy-duty pneumatic tire
  • Heavy-duty pneumatic tire
  • Heavy-duty pneumatic tire

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0112] got equipped figure 1 Pneumatic tires for heavy duty (tire size = 295 / 80R22.5) having the structure shown and having the specifications shown in Table 1 below.

[0113] The fitting part of this embodiment 1 is as shown in the structure column of table 1, has figure 1 structure shown. In this Example 1, the entirety of the core is surrounded by the cladding. The covering layer was composed of one sheet of covering ply, and the thickness Tv of the covering ply was 1.0 mm. A 940dtex nylon fiber cord is used for the covering cord. The hardness Hv of the overlay is 70. As the carcass cords, steel cords having an outer diameter d of 0.85 mm were used. The ratio (W / d) of the distance W between the covering cords to the outer diameter d of the carcass cords was 0.65. The hardness Ht of the carcass topping is 71. The difference (Ht-Hv) between the hardness Ht of the carcass topping and the hardness Tv of the covering topping is 1. The hardness Hc of the chafer was 72.

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Embodiment 3

[0116] In addition to providing a fiber reinforced layer in the fitting part, the structure of the fitting part becomes Figure 4 Except for the structure shown, the tire of Example 3 was obtained in the same manner as in Example 1. The fiber-reinforced layer consists of two reinforcing plies. This is indicated by "2" in the column "Fibre-reinforced layer" of Table 1. Nylon fiber cords are used for each reinforcing ply.

Embodiment 2

[0118] A tire of Example 2 was obtained in the same manner as in Example 3 except that the fiber-reinforced layer was constituted of one sheet of reinforcing ply.

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Abstract

Provided is a heavy-duty pneumatic tire 2 in which not only occurrence of a damage of CBU but also occurrence of pulling-out of a carcass ply 36 can be inhibited, and which has excellent durability. In the tire 2, beads 8 each include a cover 28 enclosing at least a part of a core 24. The cover 28 is located, between the core 24 and the carcass ply 36, in a portion at which the carcass ply 36 encloses the core 24. The cover 28 is composed of one cover ply 64 including a large number of aligned cover cords 66 and a cover topping rubber 68 covering the cover cords 66. A ratio of a distance between the cover cords 66 to an outer diameter of a carcass cord 56 is not lower than 0.35 and not higher than 0.85. A difference between a hardness of the cover topping rubber 68 and a hardness of a carcass topping rubber 58 is not less than -5 and not greater than 5.

Description

technical field [0001] The present invention relates to a pneumatic tire for heavy loads. Background technique [0002] The portion of the tire that fits into the rim (hereinafter also referred to as a fitting portion) includes a bead. The bead includes a core wound by a wire made of stainless steel. The carcass is erected between one bead and the other. The carcass is composed of at least one carcass ply folded back around the core. In heavy-duty tires that are mounted on vehicles such as trucks and buses, steel cords are generally used as carcass cords. [0003] A force is applied to the fitting portion of the tire so that the core portion and the carcass cord approach each other. Heavy-duty tires are used under high internal pressure and high load. Therefore, there is a possibility that fretting wear between the core and the carcass cord may occur, and damage accompanying breakage of the carcass cord (Cord Broken Up: CBU) may occur. In order to improve the durabilit...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B60C15/04B60C9/08
CPCB60C15/0072B60C15/04B60C9/08B60C2015/044B60C2009/0035B60C2009/0276B60C9/0007B60C2015/048B60C2009/0425B60C2200/06B60C2015/0614B60C15/0036B60C15/06B60C2009/0284B60C2015/009
Inventor 李庆茂
Owner SUMITOMO RUBBER IND LTD