JP3390485B2 - Bead wire - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bead wire for a tire. [0002] 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, which are important tire materials to secure the fit, 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 rectangular cross section is a bead wire in which a plurality of steel wires are arranged in parallel, covered with rubber, and the steel wire strips are laminated and wound. The single-wire bead wire having a hexagonal cross section is a bead wire in which one steel wire is covered with rubber, and the steel wire is continuously wound in parallel and laminated to form a bale-stacked shape. A cable bead wire having a circular cross section is a bead wire in which another steel wire is spirally wound around a peripheral surface of an endless metal ring. 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 could be used in a bias tire, but it was inconvenient in a radial tire and was not useful. 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,
In each case, the rubber-coated hard steel wires are mechanically arranged closely, so that it is possible to completely prevent the hard steel wires from being disordered due to the movement of the tire cord during tire vulcanization. could not. The appearance of a cable bead wire having a circular cross section that can keep the same cross sectional shape has been introduced. However, the cost of spiral winding is high, and the bead positioning during tire molding is unstable due to the circular cross section. At present, it cannot be easily disseminated due to the above problem. In recent years, due to environmental problems, extremely strict exhaust gas regulations (CAFE) have been determined that can not be achieved unless the weight of the current automobile is reduced by half, and the weight reduction of bead wires has been increasingly demanded. ing. In order to solve these problems, a technique disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 4-278611 has been known. In this conventional technique, aramid fibers are successively wound plural times in parallel and laminated in the inner cavity of a substantially U-shaped annular body having an open outer diameter side made of a synthetic resin or metal. The annular body has a straight portion on the inner diameter side, and the corner of the annular body is formed in an arc shape. According to this conventional technique, a non-metallic material is used as a material for forming a bead wire,
Since the ring body in contact with the tire cord is a substantially U-shaped cross-section, and the aramid fiber is housed in the inner cavity of the ring body, the weight can be reduced and the bead wire structure may be disturbed. Absent. In addition, by providing the linear portion on the inner diameter side of the ring body, it is possible to stably perform the bead positioning at the time of molding and vulcanizing the tire. [0009] However, in this prior art, the rigidity of the ring having a substantially U-shaped cross section is made of synthetic resin or metal. Will be very high. Therefore, there is a problem that the ring is difficult to handle, and that the high rigidity of the ring hardly contributes to the strength of the bead wire. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to significantly reduce the weight of the tire. An object of the present invention is to provide a bead wire which is easy to handle and does not hinder the bead positioning at a low cost. In order to achieve the above object, according to the present invention, at least two metal wires having a flat cross section are formed in an annular shape by continuously winding and laminating a metal wire having a flat cross section. An outer layer is provided by winding aramid fibers a plurality of times around the inner layer having a layer structure, and both layers are covered with a rubberized cloth or rubber. Therefore, according to the present invention, a non-metallic material such as aramid fiber is used for the material constituting the bead wire, and the outer layer made of the aramid fiber and the inner layer made of the metal wire are made of rubberized cloth or Covered with rubber. Therefore, the weight can be reduced, and no structural disturbance of the bead wire occurs. In addition, a metal wire having a flat cross section is continuously wound in parallel and stacked to form an inner layer, so that a straight portion is formed at least on the inner diameter side of the inner layer, that is, on the inner diameter side of the bead wire. Bead positioning during molding can be performed stably. Furthermore, since the inner layer and the outer layer are covered with a rubberized cloth or rubber, the bead wire can be made flexible and its handling is facilitated. Also, since the outer surface of the bead wire is made of a rubberized cloth or rubber, the bead wire is firmly integrated with the rubber for the tire at the time of molding and vulcanizing the tire. An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the inner layer 2 is formed in a ring shape by continuously winding and laminating a metal wire 3 such as a steel wire having a flat cross section, and has a two-layer structure. An aramid fiber 4 is continuously wound around the inner layer 2 a plurality of times in parallel and laminated to form an outer layer 5. The bead wire 1 having a square cross section is formed by integrally covering the two layers 2 and 5 with the rubberized cloth 6. In addition, 7 is a tire bead part, 8
Indicates a tire code. According to this embodiment, the bead wire 1
Since a non-metallic material such as aramid fiber 4 is used as a material constituting the above, the weight can be reduced by about 60% as compared with a conventional bead wire made of a hard steel wire. In addition, since the inner layer 2 made of the metal wire 3 and the outer layer 5 made of the aramid fiber 4 are covered with the rubberized cloth 6, the structure of the bead wire 1 is not disturbed at the time of vulcanization of the tire. Can be made flexible, and its handling becomes easy. Moreover, since the outer surface of the bead wire 1 is made of the rubberized cloth 6, the bead wire 1 is firmly integrated with the rubber for the tire via the rubber of the rubberized cloth 6 at the time of molding and vulcanizing the tire. Furthermore, bead wire 1
Has a quadrangular cross section and has a straight portion on the outer peripheral surface thereof, so that the bead positioning during tire molding can be stably performed. In addition, unlike the conventional cable bead wire, it is not necessary to perform spiral winding, and only the parallel winding and the lamination winding are required. The quality of the bead wire 1 can be provided. The present invention is not limited to the above embodiment. For example, as shown in FIG. 2, the inner layer 2 and the outer layer 5 may be covered with a rubber 9 instead of the rubberized cloth 6.
Further, as shown in FIG. 3, the outer surface of the rubberized cloth 6 may be further covered with rubber 9. Further, the configuration of each part can be arbitrarily changed and embodied without departing from the gist of the present invention, for example, the inner layer 2 has a three-layer structure or more such as a three-layer or four-layer structure. . As described above in detail, according to the present invention, the weight can be significantly reduced, no structural disturbance of the bead wire occurs at the time of vulcanization of the tire, and the bead is positioned at the time of tire molding. In addition, there is an excellent effect that there is no problem, the handling is easy, and the cost is low.

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 cross-sectional view showing another example of a bead wire. FIG. 3 is a cross-sectional view showing another example of the bead wire. [Description of Signs] 1 ... bead wire, 2 ... inner layer, 3 ... metal wire, 4 ... aramid fiber, 5 ... outer layer, 6 ... rubberized cloth, 9 ... rubber.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-193313 (JP, A) JP-A-4-183614 (JP, A) JP-A-58-145509 (JP, A) JP-A-58-145 128238 (JP, A) JP-A-4-296541 (JP, A) JP-A-5-24418 (JP, A) JP-A-62-1121039 (JP, A) JP-A-4-278811 (JP, A) JP-B-56-33244 (JP, B1) (58) Field surveyed (Int. Cl. ⁷ , DB name) B60C 15/04

Claims (1)

(57) Claims 1. An aramid fiber is formed on the outer periphery of an inner layer having at least a two-layer structure formed by continuously winding and laminating a metal wire having a flat cross section in an annular shape. A bead wire, wherein the outer layer is provided by winding a plurality of times, and both layers are covered with a rubberized cloth or rubber.