JPS6047704A - Radial tire - Google Patents

Abstract

PURPOSE:To improve the rigidity of a bead section by reinforcing the bead filler rubber with a stiffening layer made of cord raw material in one body and covering a carcass wound end in the vertical direction in a heavy-load radial tire for truck, etc. CONSTITUTION:A rubber-covered stiffening layer 13 made of cord raw material such as organic fiber is stuck in one body to the side face of a bead filler rubber 10 on the bead heel side to reinforce the bead filler rubber 10. In addition, a reinforcing layer 14 is arranged outside the stiffening layer 13 to cover a carcass wound end 16 in the vertical direction with the rubber 10 and stiffening layer 13. Thereby, the rigidity of a tire bead section 4 is improved and the durability of the tire can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radial tire, particularly a radial tire for heavy loads used in trunks or buses, and relates to a radial tire with improved durability of a bead portion.

Before explaining the present invention, a conventional tire will be explained. As shown in FIG. 5 is embedded. A carcass 6 in which a cord is arranged at approximately 90 degrees to the equator of the tire is provided between the pair of bead parts, and both ends 7 of the carcass extend from the bead toe 8 side, surround the bead core 5, and extend upward from the bead heels 9. It is said to be a rolled-up part that is rolled up.

Note that a belt layer 10 is provided at the crown portion of the carcass 6.

However, in such a radial tire, the carcass 6 is usually made of a steel cord braid, and therefore there is a problem that separation or cranking occurs in the rubber at the rolled-up end 11 of the carcass. Although not shown in FIG. 1, in order to ensure the rigidity of the bead portion 4, especially in radial tires for heavy loads, it is located outside the carcass winding portion 7 and further on the bead toe 8 side. It is common practice to provide a reinforcing layer made of a wound steel cord on the bead heel 9 side. However, in this case, there is a problem in that separation or cranking occurs at the upper end of either the carcass or the reinforcing layer.

Although not shown in FIG. 1, it is also known to fill a space between the carcass 6 and the carcass winding section 7 with hard bead filler rubber in order to improve the rigidity of the bead section 4. Although the bead filler rubber may contribute to improving the rigidity of the bead portion, it is not useful for preventing separation or cracking at the winding end.

In view of the above, an object of the present invention is to provide a radial tire that simultaneously achieves reinforcement of the rolled-up end that causes separation or cranking, and improvement of the bead section rigidity, and solves all the drawbacks of the conventional example as described above. It is.

To achieve this object, the present invention is characterized by: Rolling up both ends of a toroidal carcass provided between a pair of bead cores from the bead toe side toward one side of the bead heel (IQI), surrounding the bead cores, In a radial tire in which hard bead filler rubber is filled between a carcass and a carcass winding part, the bead filler rubber is integrally reinforced with a reinforcing layer made of a cord material, and the bead filler rubber and The reinforcing layer integrated therewith covers the rolled up end of the carcass in the vertical direction.

Embodiments of the present invention will be described in detail below with reference to the drawings.
In the first embodiment shown in the figure, a radial tire according to the present invention has a carcass 6 at a bead portion 4 surrounding a bead core 5 from a bead toe 8 side and a bead heel 9 (1,!l).
The carcass is rolled up upward, and a hard bead filler rubber 10 is filled between the carcass 6 and the carcass winding part 7. The bead filler rubber 10 can be used as a single unit, but as shown in the figure, the apex 11
Regarding the rubber hardness (JIS A hardness, hereinafter the same), it is preferable to make a composite rubber body of the sidewall packing 12 and the side wall packing 12. When the hardness of the Kuiyapodi is 60-65 degrees, the apex 11 is 80-93 degrees ( The apex 11 has a higher hardness than the side wall buckling 12. As a result, the bead filler rubber 10 reaches the sidewall 3 and evens out the hardness. Regarding the hardness value, if it is lower than the lower limit of the above value, the rubber will be too flexible and will have poor reinforcing effect and improvement in lubricating properties.On the other hand, if it exceeds the upper limit of the above value, the hardness will be too high and will cause heat generation during running. Invite.

Further, there is a risk that the rubber itself may crack when bent.

On the other hand, the bead filler rubber 10 has a reinforcing layer 13 on the entire side surface on the bead heel side.

It may also be integrally reinforced by the reinforcing layer 13. This reinforced Wi 13 is made of a cord material of organic m141: or inorganic paper f4fj, for example, a cord of textile or car steel, or a cord strength of glass fiber, aramid fiber or carbon fiber (the cord direction is lazoal). This reinforcing layer 13 is covered with rubber from the upper blade 1 in which the cords are arranged, and the bead filler rubber 10 is integrally bonded with rubber. In the illustrated example, one ply of the code layer is shown as the fourth layer 13, but it is free to be composed of a plurality of plies.

Further, a reinforcing layer 14 is disposed outside the reinforcing layer 13. This reinforcing layer 14 is made of organic or inorganic fiber cord material as described above.

In the example shown in FIG. 8 where one or more plies of the cord layer are formed one year ago, the carcass winding end 16 is located lower than the upper end 15 of the reinforcing layer 14 (Low Ply Turn tlp). However, it is free to use a high ply turn-up structure (Illight Ply Turn Llp) in which the carcass winding θlit 16 is arranged above the upper end 15 of the reinforcing layer. The lower end 17 of this reinforcing layer 14 is preferably placed between the center side of the bead core 5 and a position near the upper end of the rim flange 18, but as shown by the imaginary line, the reinforcing layer 14 is wrapped around the bead toe 8 side. It is free to form the winding part 19.

Then, the bead filler rubber integrally reinforced by the reinforcing layer 13]0 rolls up the carcass kJ'&I:A 16 by both the rubber 10 and the reinforcing layer 13.
It is coated downward. Preferably, both the rubber 10 and the reinforcing layer 13 further cover the upper end 15 of the reinforcing layer 15 in the vertical direction.

FIG. 3 shows a second embodiment of the invention.

The bead filler rubber 10 consists of a single rubber body, and a reinforcing layer 13' is embedded vertically along the cross section of the rubber body. In this case, the hardness of the bead filler rubber 10 is 55-
It is 90 degrees (preferably 60-80 degrees) and has a higher hardness than the rubber of the tire body. The other configurations regarding the material of the fifth reinforcing layer 13', the configuration regarding the reinforcing layer 14, etc. are the same as those of the first embodiment, and are designated by the same reference numerals.

FIG. 4 shows a third embodiment of the invention.

The bead filler rubber 10 has a reinforcing layer 13 placed and integrated on the outside of the rubber as in the first embodiment, and a reinforcing layer 13° is embedded in the rubber as in the first embodiment. are doing. The rubber hardness is the same as in the second embodiment, and the other configurations are the same as in the first embodiment.
In the embodiment, as shown by the imaginary line, it is optional to extend the rubber outer reinforcing layer 13 to provide an extended reinforcing layer 13'' that surrounds the rubber. In this case, two reinforcing layers 13 and The joint 20 with the extended reinforcing layer 13' may be either a butt joint where both ends are brought together, or an overlamp joint where both ends are overlapped.

FIG. 5 shows a fourth embodiment of the invention.

The heat filler rubber 10 is a composite rubber layer consisting of an apex 11 and a sidewall backing 12, as in the first embodiment. - The force reinforcing layer 13 extends upward from the bottom of the bead filler rubber 10 along both the inner and outer sides as shown. The other configurations are the same as those of the first embodiment.

As a result of the present invention configured as described above, the bead filler rubber 10 filled between the carcass 6 and the carcass winding part 7 is made of high hardness rubber and reinforced IFt 13, 13' and/or 13, the rigidity of the tire bead portion 4 is significantly improved with such a simple structure, and therefore the durability is significantly improved especially as a radial tire for heavy loads. Moreover, since both the hard bead filler rubber 10 and the reinforcement 1'513.13'' and/or 13°' integrated therein cover the carcass winding end 16 in the vertical direction, the carcass 9) It is excellent in that it can effectively suppress the occurrence of separation or cracks in the rubber at the rolled end.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional tire, FIG. 2 is an enlarged explanatory view showing a cross section of a bead portion according to a first embodiment of the present invention, and FIG. 3 is an enlarged explanatory view showing a cross section of a bead portion of a second embodiment. FIG. 4 is a sectional view showing the bead filler rubber according to the third embodiment;
The figure is a sectional view showing a bead filler rubber according to a fourth embodiment. 4... Bead part, 5... Bead core, 6... Carcass, 7... Carcass winding part, 10... Beat filler rubber, 11... Apex, 12...
・Side wall backing, 13.13', 13°°
... Reinforcement layer, 14 ... Reinforcement layer, 16 ... Carcass winding end.

Claims (1)

[Claims] 1. Both ends of a toroidal carcass provided between a pair of bead cores are rolled up from the bead toe side surrounding the bead cores toward the bead heel side, and a hard material is placed between the carcass and the carcass winding part. In a radial tire filled with a bead filler rubber; the bead filler rubber is integrally reinforced with a reinforcing layer made of a cord material; the bead filler rubber and the reinforcing layer integrated therewith are A radial tire characterized by having the rolled up end of the carcass covered in the vertical direction.