JP2746764B2 - Bead wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bead wire for a tire.

[0002]

2. Description of the Related Art A fiber or a steel wire cord forming a carcass, which is a strength member for maintaining an internal pressure of a tire, is wound around and fixed to the end of the tire. The bead wires that are important tire materials to be secured are (1) a strand bead wire having a square cross section, (2) a single bead wire having a hexagonal cross section, and (3)
It is classified into three types of cable bead wires having a circular cross section.

A strand bead wire having a square cross section is a bead wire in which a plurality of steel wires are arranged in parallel and covered with rubber, and the steel wire strip is laminated and wound. A single bead wire having a hexagonal cross section is a single steel wire. This is a bead wire that has been covered with rubber, and the steel wire is continuously wound in parallel and in layers, so that it has a bale-stacked shape.The cable bead wire with a circular cross section has another steel wire attached to the peripheral surface of the endless metal ring. Is a bead wire spirally wound.

A strand bead wire having a square cross section has a drawback that the cross sectional shape is easily distorted when embedded in a tire carcass and molded and vulcanized, so that it can be used even with a bias tire, but is inconvenient and useful with a radial tire. Is gone. Hexagonal cross-section bead wires, whose cross-sectional shape is unlikely to change during tire molding and vulcanization, subsequently appeared, but were useful for certain truck tires with a low shape of so-called 15-degree taper,
Generally, in a bead wire in which steel wires are arranged in parallel, the effective strength used for a finished tire is about 40% of the inherent strength of the wire.

A bead wire having the same cross-sectional shape and preferably having a circular cross-section as a whole is ideal. In particular, a bead wire having a circular cross section is optimal for a tire using a steel cord for a carcass such as an all-steel radial tire. This is the reason for the appearance of cable bead wires with a circular cross section. Around a butt-welded circular or low-carbon steel wire with a circular cross-section (some cross-sectional shapes other than a circular cross-section such as a rectangular cross-section) having the same cross-sectional shape in the length direction In addition, a cable bead wire formed by closely arranging a high carbon steel wire in a spirally wound manner enables about 75% of the material strength to be used as effective strength. This cable bead wire has the above-mentioned effect because the spirally wound wire is closely arranged while turning around the core metal without interposing thermoplastic rubber. As described above, with the advent of the cable bead wire, the effective use of the material of the bead wire has been improved almost twice, the weight of the bead can be reduced, and the cross-sectional area thereof can be reduced, thus greatly contributing to the reduction of the weight of the tire.

[0006]

However, especially in the case of a bead wire for a large tire, even if the above-mentioned structure is adopted, two or three spiral windings are required, so that the production cost is increased and the spread is widespread. Not much progress. In recent years, due to environmental problems, extremely strict exhaust gas regulations (CAFE) have been determined that cannot be achieved unless the weight of the current automobile is reduced by half, and the weight reduction of bead wires has been increasingly demanded.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to significantly reduce the weight of a cable bead wire and to reduce the manufacturing cost of a cable bead wire of a large tire. An object of the present invention is to provide a bead wire that can be more widely used.

[0008]

To achieve the above object, according to the solution to ## in this invention, cross-sectional circle forming a non-metallic endless
After spirally winding a metal or non-metallic linear material at a predetermined pitch on the peripheral surface of the annular body having a predetermined shape, and completing one round of winding, pull the wire.
Subsequently carried adjacent the next spiral winding, which was more peripheral helical winding a wire material repeatedly, linear material of the spiral winding,
Short side of the inner diameter side in contact with the outer peripheral surface of the annular body, the outer diameter side is formed at least one layer of linear material having a trapezoidal cross section and long sides, a planar side surface of the adjacent linear material together The outer peripheral surface of the linear material is in a circular cross section .

[0009]

[0010]

Therefore, according to the present invention, a non-metallic material is used as a material for forming a bead wire, and a wire formed by laminating a plurality of layers is wound one layer, thereby reducing the weight and spirally winding the wire. The number of times can be reduced.
According to the present invention, a spiral winding made of a linear material having a trapezoidal cross section is provided.
The line is a carcass cord centered around a circular body with a circular cross section.
Rotate together to form a tire carcass during tire vulcanization.
The cord is flexible to the stress that the bead wire inevitably receives.
It is possible to respond softly.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, a plurality of Kevlar fiber bundles 4 made of aramid fibers are provided on the peripheral surface of an endless annular body 2 in which glass fibers are embedded in an epoxy resin.
(Kevlar is a trade name of DuPont) A spirally wound linear material 3 made of a Kevlar laminate 5 in which two layers are laminated. Then, this linear material 3 is spirally wound at a pitch of one turn of the annular body 2 for six turns, and then similarly wound two turns,
Circumference... Circumferentially, the bead wire of the present invention is obtained by surrounding the entire peripheral surface of the annular body 2 after eleven revolutions. Reference numeral 7 denotes a tire bead portion. As is clear from FIG. 1, the wire material 3 for spiral winding
When wound on the endless annular body 2, the short side that becomes the inner diameter and the long side that becomes the outer diameter are arc-shaped, and the left and right sides are flat trapezoidal cross sections. Since the left and right side portions are almost in close contact with the left and right side portions of the adjacent linear member 3, they are extremely stable.

In another example shown in FIG. 3, a plurality of Kevlar fibers
Wrap 4 with nylon fiber 6 (linear material)
The wire 3 is constituted.

[0013]

As described in detail above, according to the present invention, for example, in the case of a bead wire made of a conventional all-steel wire having a size of 20 inches and 1 × 6 + 11 + 17 × 2.2,
The standard weight is 1800 g and the number of spiral turns is 1
The layer has 11 × 6 = 66 times and the second layer has 17 × 6 = 102 times, requiring a total of 168 times. However, in the bead wire of the present invention, the weight is reduced by about 65% and the number of spiral windings is reduced. However, there is an excellent effect that the cost can be reduced by 66/168, that is, about 60%, and the manufacturing cost can be reduced. Further, according to the present invention, the tire is
Bead wire is inevitably received by the carcass cord
This makes it possible to flexibly respond to stresses that occur.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a bead wire embodying the present invention .

FIG. 2 is a partially enlarged perspective view of a linear material .

FIG. 3 is a cross-sectional view of another example of a bead wire .

[Explanation of symbols]

2 annular body 3 linear material 4 fiber bundle

Claims (1)

(57) [Claims] 1. A peripheral surface of the section forming a non-metallic endless circular annular body (2), metal or non-metallic linear member (3)
Is wound spirally at a predetermined pitch to complete one round of winding, and then the next spiral winding is performed adjacently, and this is repeated to obtain a bead wire obtained by spirally winding the linear material (3) a plurality of times. The helically wound linear material (3) has at least one layer of a linear shape having a trapezoidal cross section in which the short side is the inner side and the long side is the outer side in contact with the outer peripheral surface of the annular body (2). A bead wire formed of a material (3), wherein planar side surfaces of adjacent linear materials (3) are in contact with each other , and an outer peripheral surface of the linear material (3) is formed in a circular cross section. .