KR101829539B1 - Cable Bead for Tire and Radial Tire using the same - Google Patents

Abstract

The present invention relates to a cable bead core for a tire which improves the rigidity of a cable bead portion and enhances ride comfort by compensating for weakness of a core wire, and a radial tire using the cable bead core.
In a cable bead core for a tire including a core wire and an outer wire wire wound and twisted around the core wire, the core wire is made of die casting and the core wire is made of magnesium or a magnesium alloy. At the core wire, at least one of aluminum, manganese, silver, zinc, silicon or rare earth metals is added within 2wt% at the time of casting, and the outer surface of the outer wire is brass, bronze or galvanized.
The cable bead core for a tire and the radial tire using the cable bead core according to the present invention have the effect of enhancing the rigidity of the cable bead portion by enhancing the structural weakness of the core wire and improving the riding feeling because of excellent vibration damping and vibration absorbing power.

Description

{Cable Bead for Tire and Radial Tire using the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable bead core for a tire and a radial tire using the cable bead core, and more particularly, to a cable bead core for a tire that improves the rigidity of a cable bead portion and enhances ride comfort by compensating for weakness of a core wire.

The bead portion of the tire is the portion where the tire is in contact with the rim of the wheel. In addition to fixing the tire to the rim, the bead supports the load applied to the tire, and the torque of the torsion and braking Which is an important factor in terms of durability, that is, stability, depending on the rigidity of the bead portion. Also, depending on the shape and structure of the bead portion, the ride comfort of the vehicle is greatly influenced.

The bead part is roughly divided into two types. A method of stacking a high carbon steel wire rod in a desired shape using wires manufactured to a desired size, and a method of making a bead in a cable form by twisting the wires manufactured in the same manner.

1 is a sectional view showing a bead portion having a cable bead core in a general radial tire. As shown in the figure, the bead portion 10 includes a cable bead core 11, first and second bead fillers 12 and 13 provided on the outer side and the upper side of the cable bead core 11, a cable bead core 11, And a carcass 14 for enclosing the first and second bead fillers 12 and 13.

The cable bead core 11 consists of a core wire and an outer wire. The core wire is mainly made of low carbon steel with a carbon content of 0.1 wt% or less. After the wire is formed into a circular shape with a desired diameter, both ends of the core wire are welded and the outer wire wire is wound around the core wire to form a cable bead core 11). The outer wire wire is made of high carbon steel having a carbon content of 0.7 wt% or more. The core wire serves as a skeleton of the cable bead core 11 and adjusts the number and diameter of the outer lines to obtain desired rigidity.

The cable bead core 11 is less lightweight than the method of laminating with a single wire, and there is no difference in weight between the parts in the circumferential direction, thereby improving tire durability and uniformity.

However, in the conventional cable bead core, since the wire must be welded at the stage of manufacturing the core wire, the welded portion becomes the weakest position in the cable bead core, and about 70 ~ 80% There is a problem that breakage occurs in the strength of

Korean Patent Laid-Open Publication No. 2013-0049552 (Publication date: 2014.05.14.)

SUMMARY OF THE INVENTION The present invention has been accomplished to solve the above-mentioned problems, and it is an object of the present invention to provide a cable bead core for a tire that enhances the rigidity of a cable bead portion and enhances ride quality by compensating for a structural weakness of a core wire, and a radial tire using the cable bead core have.

In order to achieve the above object, a cable bead core for a tire according to the present invention is a cable bead core for a tire including a core wire and an outer wire wire wound around the core wire, wherein the core wire is manufactured by die casting casting.

The core wire is made of magnesium or a magnesium alloy. It is preferable that at least one of aluminum, manganese, silver, zinc, silicon or a rare-earth metal is added to the core wire at 2 wt% or less during casting.

The outer surface of the outer wire is preferably brass, bronze or zinc plated.

The cable bead core for a tire and the radial tire using the cable bead core according to the present invention have the effect of enhancing the rigidity of the cable bead portion by enhancing the structural weakness of the core wire and improving the riding feeling because of excellent vibration damping and vibration absorbing power.

1 is a sectional view showing a bead portion having a cable bead core in a general radial tire.
2 is a cross-sectional view showing a cable bead core for a tire according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that, in the drawings, the same components are denoted by the same reference symbols as possible. Further, the detailed description of known functions and configurations that may obscure the gist of the present invention will be omitted. For the same reason, some of the components in the drawings are exaggerated, omitted, or schematically illustrated.

FIG. 2 is a cross-sectional view showing a cable-use bead core according to an embodiment of the present invention. The ladle tire to which the present invention is applied includes a tread which is a rubber layer in contact with the road surface, a side wall connected to the tread and a side wall of the tire, a side wall connected to the sidewall, A bead portion, a carcass which is provided inside the tire and forms a skeleton with a high fatigue resistance against the sideways motion of the sidewall, and a carcass which is disposed between the tread and the carcass to protect the carcass, And a belt for improving the rigidity of the belt. Hereinafter, a detailed description of the portion constituting the tire other than the bead core of the bead portion provided at the end of the sidewall will be omitted.

The cable bead core 110 includes a core wire 111 made of an annular core and an outer wire wire 112 wound around the core wire 111.

The core wire 111 made of annular core is manufactured by die casting casting without welding and surface treatment. Casting is a method of heating a material to a temperature higher than its melting point, making it into a liquid, and injecting a liquid into a desired mold to solidify it. In the present invention, a die casting casting method which applies a high pressure to such a casting is used. Die casting is a commonly known method, so a detailed description is omitted.

Magnesium or a magnesium alloy is used as the metal material used for casting the core wire 111. Since magnesium has a specific gravity of 1/3 of aluminum alloy and 1/4 of iron, the weight of cable bead cores can be lightened. The strength level per weight of magnesium is more than three times that of conventional low carbon steel. In order to improve the physical properties of the core wire 111, it is preferable to use a magnesium alloy to which various elements are added. As the metal to be added, there are Al (aluminum), Mn (manganese), Ag (silver), Zn (zinc), Si (silicon), and rare earth metal. It is preferable that the additive metal is used within 2 wt%.

Al (aluminum) has an effect of improving mechanical properties, Mn (manganese) has an effect of improving corrosion resistance, Ag (silver) has an effect of improving heat resistance, Zn (zinc) has an effect of improving corrosion resistance and strength Si (silicon) has the effect of improving the creep strength, and the rare earth metal has the effect of improving the mechanical properties.

On the other hand, magnesium is a metal material with excellent vibration damping ability when it undergoes a stress cycle of understanding the durability of the material. When the core of the bead core is made of magnesium in the tire bead portion subjected to continuous vibration, it can absorb the vibration generated continuously in the tire, thereby improving the ride comfort and absorbing the vibration to additionally increase the life of the bead portion.

The core wire 111 is manufactured by casting and is not subjected to any surface treatment, while the outer wire wire 112 is plated for adhesion reaction with rubber. Plating shall be made of brass or bronze or galvanized, depending on the purpose and type of rubber used.

Hereinafter, a test example of a cable bead core for a tire and a radial tire using the cable bead core according to the embodiment of the present invention will be described below.

The bead cores were made of two types of cable bead cores with 1 + 6 (1.60) HT structure (core wire welding and core wire casting) to compare the properties. As shown in FIG. 2, the 1 + 6 structure is a cross-sectional structure in which a core wire is located inside and six outer wire wires surround the core wire.

[Table 1] is a test example in which the strength of a cable bead core is compared.

division 1 + 6 (1.60) HT
(Core wire welding) 1 + 6 (1.60) HT
(Core wire casting) Theoretical Strength (kgf) 2730 2730 Actual force (kgf) 1945 2523 (Actual / theory) * 100 71 92

As shown in Table 1, when the core wire is welded, the strength is about 70% of the theoretical strength, whereas when the core wire is cast, the strength is 92% of the theoretical strength have.

Table 2 shows a test example in which the running performance of each radial tire manufactured using a cable bead core having two types of bead core structures was compared and evaluated. The evaluation was carried out through an indoor truck until the tire tread was peeled off at 100% of the air pressure, 150% of the load, and 80 km / h and the bead accident occurred (when the bead burst).

Category (hr) Comparative Example
(Core wire welding) Example
(Core wire casting) Rating 1 48 72 Rating 2 51 65 Rating 3 50 68 Average 50 68

As shown in Table 2, it can be seen that in the embodiment of the present invention (core wire casting), the running time increased by 36% as compared with the comparative example (core wire welding).

Table 3 is a test example in which the difference between the vibration damping effect and the vibration absorbing degree is compared by conducting the actual vehicle test with each radial tire manufactured using the cable bead core having two types of bead core structures. We used a method to qualitatively evaluate the sensation felt by the driver (driver) during the test. The vehicle used was the NF Sonata, and the tire used in the actual vehicle test was 215 / 60R16 H433. In this test, Enveloping and Bounce Damping items were compared.

Test Items Comparative Example
(Core wire welding) Example
(Core wire casting) Enveloping 6 7 Bounce Damping 7 8

The actual vehicle evaluation result is evaluated by the test driver with a score between 1 and 10, and the higher the value, the higher the performance. Enveloping is an item that evaluates absorption and buffering of generated vibration. Bounce Damping measures the degree of attenuation of the generated vibration. Both of the items show that the performance of absorbing and attenuating the generated vibration in the embodiment of the present invention is improved as compared with the comparative example. Therefore, it can be seen that there is also an effect of improving the handling performance.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of the present invention in order to facilitate the understanding of the present invention and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

110: bead core
111: core wire 112: outer wire wire

Claims (5)

1. A cable bead core for a tire comprising a core wire made of an annular core and an outer wire wire wound around the core wire made of the annular core,
Wherein the core wire made of the annular core is manufactured by die casting casting without welding and surface treatment. The method according to claim 1,
Wherein the core wire made of the annular core is made of magnesium or a magnesium alloy. The method of claim 2,
Wherein at least one of aluminum, manganese, silver, zinc, silicon or a rare earth metal is added to the core wire made of the annular core within 2 wt%. The method according to claim 1,
Wherein an outer surface of the outer line wire is brass-plated, bronze-plated or galvanized. A radial tire comprising: a cable bead core for a tire according to any one of claims 1 to 4.

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