KR100288052B1 - Tire bead composed of steel wire - Google Patents

Abstract

PURPOSE: A tire bead composed of a steel wire is provided to extend a life span of a tire by improving resistance of contacting force and to save resources. CONSTITUTION: A bead unit is connected to a rim by being formed on a tire. A bead core(2) of the bead unit is composed of a steel wire to be inserted to the rim. A carcass fly surrounds the bead core by forming a body of the tire. The carcass fly is composed of a coating rubber(3). The bead unit fixes the carcass fly and closes air of an inner portion of the tire. A bead wire(5) is formed as an oval shape by applying to a fibonacci ratio. Thus, the bead core reduces deformation of the bead unit. Thereby, the tire bead composed of the oval steel wire extends a life span of the tire by improving resistance of contacting force between the bead unit and the rim. Moreover, the tire bead composed of the oval steel wire reduces resources by extending the life span of the tire.

Description

Tire beads made of steel wire

In order for a tire to perform its function, it must first be mounted on a wheel and injected with air. The outer periphery of the wheel is called a rim, and the tire is mounted on this part and the tire and the rim are driven by a compression force acting therebetween. These forces are combined with each other and the forces acting on the tires are transmitted to the wheels. Therefore, the design of this part of the tires is very important because it depends on the performance of the tires such as mountability and steering stability depending on the relationship between the tires and the rims. Have

As shown in FIG. 1, a part of the tire connected to the rim is called a bead part. The bead part has a bead core made of a material such as a steel wire which does not stretch, and is fitted to the rim to form a car. The casing ply wraps around it, and is made of relatively hard coated rubber that substantially contacts the rim, and serves to hold the carcass ply constituting the body and to support it so that it does not extend in connection with the rim. By interfering with the mounting function to seal the air inside the tire.

Due to this relationship, most of the forces and moments acting on the bead portion of the tire are supported by the bead core, which is the air pressure inside the tire, the various loads transmitted through the ground, the centrifugal force and the tire generated by the rotation of the tire. Mounting force due to interference mounting with the rim is received.

In general, the bead core is composed of a plurality of steel wire, that is, bead wire having a circular or rectangular shape, as shown in FIG. 2, the bead core of the conventional passenger car tire is a rubber coated circular steel wire 4-6 Swivel bead cores made of four to six turns of wires were used, but circular bead wires are advantageous in terms of their mountability, but because of their low resistance to moment of inertia, deformation is caused by various forces acting on the bead portion. In other words, when the tire is subjected to pneumatic pressure and vertical load, the bead portion receives a strong moment to the outside of the tire, so that the bead core also twists to the outside of the tire, whereas the rectangular bead wire has a moment of inertia than a round steel wire. It is large, which is advantageous in terms of deformation resistance and maneuvering stability, but has a disadvantage in that it is mountable.

The present invention is to change the shape of the steel wire constituting the bead core as described above from the conventional circular or rectangular to elliptical to improve the mounting and steering stability by the bead wire at the same time, the shape of the steel wire Before presenting a method for determining the optimal ratio of the major and minor axis of an ellipse in setting an ellipse, the Fibonacci ratio (FIBONACCI RATIO) is described, indicating that the ratio of two neighboring numbers in Fibonacci's found sequence approaches 0.618034. As you can see, this ratio is called Fibonacci ratio, but it is a unique irrational number, but there are many mathematical relations and it is used a lot in nature and everyday life.

This Fibonacci ratio is not only applied to the horizontal and vertical ratios of cards used in Western card games, but also to the UN building, Buddha statues, eggs, ears, and snails. The tire also uses this Fibonacci ratio to set multiple radii of curvature in the tread section.

Therefore, when changing the shape of the bead wire from the conventional circular or rectangular to elliptical, the Fibonacci ratio is applied to the ratio of the long axis and the short axis required for the specification of the ellipse. In other words, the elliptical bead wire determines the ratio of the major and minor axis of the ellipse by applying the Fibonacci ratio, which is the golden ratio of nature.

The three cross-sectional shapes are then considered as shown below to calculate and compare the polar moments of inertia for round, oval and rectangular wires.

Where I is the polar moment of inertia and the polar moment of inertia increases in the order of circular <oval <rectangular wires as described above, so that the resistance to the moment of the bead portion increases in the order of circular <oval <rectangular wires, but it is difficult to manufacture rectangular bead wires. Although difficult and manufacturable, sharp ends can cause cracks. Therefore, the application of elliptical bead cores rather than circular wire bead cores can increase the moment of inertia by about 12%, thereby reducing the deformation of the bead portion and improving the mountability.

1 is a cross-sectional view showing a bead portion structure of a general pneumatic tire,

2 is a cross-sectional view of the bead core of the conventional bead portion,

3 is a cross-sectional view of the bead core of the bead portion according to the present invention.

(Explanation of symbols for the main parts of the drawing)

1 ... Carcass Fly, 2 ... Bead Core,

3 ... coating rubber, 4 ... round bead wire,

5 ... Elliptical bead wire.

Figure 3 shows a bead core made of elliptical steel wire according to the present invention, the cross-sectional shape of a number of steel wire has an elliptical wire, as shown in the ratio of the long axis and short axis of the elliptical steel wire is 0.5 to In the range of 0.9 or more ideally, the Fibonacci ratio (0.618034) was applied to the ratio to improve the bead performance of the tire.

By applying the Fibonacci ratio as described above, the tire according to the present invention composed of elliptical steel wire adopts the bead of the present invention, and the steering stability, which is the advantage of the rectangular wire, is also improved. In addition, the elliptical wire increases the area of the lower end of the wire where stress is concentrated than that of the circular wire, thereby increasing resistance to contact with the rim, thereby extending the life of the tire, thereby reducing raw materials and saving resources. It is a very useful invention.

Claims (2)

A tire bead consisting of a plurality of steel wires, wherein the ratio of the long axis and the short axis of the oval steel wire is 0.5 to 0.9, wherein the tire bead consisting of the steel wire. The tire bead made of steel wire according to claim 1, wherein the ratio of the long axis and short axis of the elliptical steel wire is the Fibonacci ratio (0.618034).