JPH0333525B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a bead ring used in a pneumatic tire for a vehicle.

[Problems to be solved by conventional technology and invention]

Conventionally, bead rings used in pneumatic tires for vehicles such as automobiles are made by arranging a plurality of round wires 1 in the axial direction of the bead ring and covering them with rubber 2 to form a bead layer, as shown in Figure 1A. , a bead ring 3 formed by laminating and winding the layers to form a plurality of layers, or a bead layer in which the surface of a single round wire 1 is coated with rubber 2 as shown in FIG. There is a bead ring 3 formed by winding. However, the above bead ring has the following drawbacks.

(1) Since the bead ring is composed of many round wires, the cross-sectional shape of the bead ring is unstable.

(2) Since the round wires tend to move easily, the load is distributed unevenly to each round wire, and sufficient breaking resistance cannot be obtained as a whole.

(3) It is difficult to mold the bead ring.

Therefore, recently, a bead ring 3 made of a flat hard steel wire 4 having a quadrilateral cross section as shown in Fig. 2 has been considered as a bead ring that improves the above drawbacks. The cross-sectional shape of the bead ring is more stable than that using a bead ring.

Since the filling ratio of the hard steel wire to the cross-sectional area of the bead ring has been improved, the resistance to breakage has improved.

It is excellent in such respects.

However, there are still problems in the following points.

' Because the hard steel wire has a quadrilateral cross section, the rubber coating tends to crack at the corners.

´ Because the hard steel wires are in close contact with each other on all sides, there is no slippage in the vertical and horizontal directions, resulting in extremely poor flexibility.

[Means to solve the problem]

The present invention has been made to eliminate the above-mentioned drawbacks, and provides a bead ring in which a plurality of hard steel wires are arranged in the axial direction of the bead ring to form a layer, and the layers are laminated and wound. The hard steel wire has two opposing sides parallel to the axial direction, and is made of a combination of a flat wire arranged so that its cross section is horizontally long, and a round wire with a circular cross section, and the layer is a combination of a round wire and a round wire. The flat wires are arranged alternately, and the surfaces of the flat wires that contact each round wire are flat, and the flat wires are arranged at both ends of the layer, and the outer surfaces of the flat wires arranged at both ends are flat. By forming the bead ring with an arcuate surface, a bead ring with improved shape stability without reducing flexibility is provided.

In the present invention, the flat line with a cross-sectional shape having two opposing sides parallel to the axial direction of the bead ring is as follows:
A rectangle or a flat wire with one side in the radial direction of the bead ring shaped like an arc is used.

Although these bead rings are ultimately coated with rubber and used in tires, there are methods in which the bead rings are molded without any rubber coating at all during the forming process, or in which the rubber coating is applied layer by layer. However, the method of finishing it into a bead ring can be applied.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

Embodiment In Fig. 3A, 5 and 7 are flat lines with a cross-sectional shape having two opposite sides parallel to the axial direction of the bead ring, and the flat line 5 has an arc surface on either side in the radial direction of the bead ring. , the other is made up of a plane perpendicular to the axial direction of the bead ring, and the flat line 7 is made up of a plane whose both sides in the radial direction of the bead ring are parallel and perpendicular to the axial direction of the bead ring. .
Further, 6 is a round wire, and this round wire 6 is arranged between the above-mentioned flat wires so as to be in contact with the plane in the radial direction of the bead ring of each flat wire, and further, flat wires are arranged at both ends of the layer. They are combined so that the arcuate surfaces of No. 5 are located on the outer surface.

A bead ring 9 as shown in FIG. 3B is formed by winding a plurality of layers so as to form a layer 8 in which a flat wire and a round wire are combined as described above. The cross-sectional shape of the bead ring 9 formed in this way is the third
The result will be as shown in Figure C.

〔Effect of the invention〕

Because the bead ring of the present invention has the above structure, it has much better shape stability than the conventional bead ring that is made only of round wire, and is also made of only flat hard steel wire that has a quadrilateral cross section. It has superior flexibility compared to traditional bead rings. Furthermore, by combining flat wires and round wires, bead rings that have the breaking strength and flexibility required for tires can be manufactured extremely easily.

Furthermore, the bead ring according to the present invention has approximately twice the durability and approximately 20% more resistance to breakage than conventional bead rings, and the rounded corners of the bead ring prevent cracks in the covering rubber. It has excellent effects such as not causing any problems.

[Brief explanation of drawings]

Figure 1 shows a bead ring using a conventional round wire, A, B, and C are partially cutaway longitudinal sectional views of different bead rings, and Figure 2 shows a part of a bead ring using a conventional flat wire. 3 shows an embodiment of the bead ring of the present invention, A is a sectional view of the layers constituting the bead ring, B is a front view of the bead ring, and C is a cut along line A-A at B. FIG. 1, 6... Round wire, 2... Rubber, 3, 9... Bead ring, 4, 5, 7... Flat wire, 8... Layer.

Claims (1)

[Claims] 1. In a bead ring formed by arranging a plurality of hard steel wires in the axial direction of the bead ring to form a layer and winding the layers in a laminated manner, the hard steel wires constituting the layer are arranged on two opposing sides parallel to the axial direction. The above layer consists of a combination of flat wires arranged so that their cross sections are horizontally elongated and round wires with circular cross sections. A bead ring characterized in that the surface in contact with the layer is flat, flat wires are arranged at both ends of the layer, and the outer surfaces of the flat wires arranged at both ends are formed into arcuate surfaces.