JP2004230941A - Structure of tire bead section, and pneumatic tire having tire bead section - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of a tire bead section capable of improving productivity of a bead core, preventing jumping of a tow section inside the tire bead section, and improving stability and durability of the tire bead section, and a pneumatic tire having the tire bead section. <P>SOLUTION: In the bead core 6 buried in the tire bead section 5, a core body 6a located in a heel section 8a outside the tire bead section and a projection 6b located in the toe section 8b inside the tire bead section are integrally formed of one bead wire as shown in the Fig. The tire bead section is manufactured in one process by winding, like ring by one rubberized bead wire, the large angular core body 6a located in the heel section 8a and the small angular projection 6b located in the toe section 8b connecting to it. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a structure of a tire bead portion and a pneumatic tire having the tire bead portion, and more specifically, to prevent a tire bead portion located on a toe portion inside a tire bead portion of a heavy-duty pneumatic radial tire from jumping up. In addition, the present invention relates to a structure of a tire bead portion in which productivity of a tire bead portion is improved and stability and durability of the bead portion are improved, and a pneumatic tire having the tire bead portion.
[0002]
[Prior art]
Conventionally, as a structure of a tire bead portion of a heavy-duty pneumatic radial tire, for example, as shown in FIG. 4, a carcass ply 11 is extended from a tread portion to a bead portion 12 via a sidewall portion, In general, a method is employed in which a region is wound around the hexagonal bead 13 embedded in the bead portion 12 from the inside to the outside of the tire, embedded and fixed.
[0003]
By the way, recently, in order to improve the durability at the tire bead portion and to avoid the occurrence of rim misalignment, settling, or separation at the carcass ply rewinding portion, the bead core and the sub-bead core have been divided into two in recent years. There has been known an arrangement in which a heel portion on the outer side and a toe portion on the inner side of the tire bead portion are provided (for example, see Patent Document 1).
[0004]
[Patent Document 1]
JP-A-2000-301917 (pages 2 to 4, FIG. 1).
[0005]
[Problems to be solved by the invention]
However, such a conventional tire bead structure has a structure in which a bead core on the heel portion outside the tire bead portion and a sub-bead core on the toe portion inside the tire bead portion are separately embedded to have rigidity. Therefore, there are many man-hours for assembling, so that not only cannot productivity be improved, but also it cannot be manufactured at low cost.
[0006]
The present invention focuses on such conventional problems, and can improve the productivity of the bead core, prevent the toe portion inside the tire bead portion from jumping up, and improve the stability and durability of the tire bead portion. It is an object of the present invention to provide a structure of a tire bead portion and a pneumatic tire having the tire bead portion.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a tire bead portion having a structure in which a single bead wire is continuously wound to form a ring-shaped bead core. The gist is that a core body located on the heel portion outside the tire bead portion and a protrusion located on the toe portion inside the tire bead portion are integrally formed.
[0008]
Here, the cross-sectional shape of the bead core is formed so as to widen toward the toe portion inside the tire bead portion.
[0009]
As described above, since one bead wire is continuously wound to form a ring-shaped bead core, the productivity of the bead core can be improved, and the toe portion inside the tire bead portion can be prevented from jumping up. You can do it.
[0010]
Further, the pneumatic tire provided with the tire bead portion of the present invention includes, in the tire bead portion, a core body located on the heel portion outside the tire bead portion, and a protrusion located on the toe portion inside the tire bead portion. The gist is to embed a bead core integrally formed by one bead wire.
[0011]
Since the pneumatic tire having such a structure is used, the stability and durability of the tire bead portion can be improved.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0013]
FIG. 1 shows a half-sectional view of a pneumatic radial tire for heavy loads embodying the present invention. In this pneumatic radial tire 1, at least one or more carcass plies 2 are connected to a tread portion 3 to a sidewall portion 4. It is configured to be wrapped around a bead core 6 embedded in the tire bead portion 5 after passing through. Reference numeral 7 denotes a tire rim mounted on the tire bead portion 5.
[0014]
As shown in FIG. 2, the bead core 6 embedded in the tire bead portion 5 includes a core body 6a located on the heel portion 8a outside the tire bead portion, and a protrusion 6b located on the toe portion 8b inside the tire bead portion. Are integrally formed by one bead wire.
[0015]
That is, in this embodiment, a bead wire obtained by rubberizing a large mountain-shaped core body 6a located on the heel portion 8a and a small mountain-shaped projection portion 6b located on the toe portion 8b in succession to this. And is manufactured in a single process while being wound in a ring shape.
[0016]
In the bead wire winding process, as shown in a winding diagram X in FIG. 2, winding is started from one end Sa side which is a skirt portion of the bead core 6, and the core body 6a having two large and small cores is sequentially laminated. And the protrusion 6b are manufactured continuously and integrally, so that the bead core 6 having only two terminal portions Sa and Sb of the bead wire can be provided.
[0017]
The cross-sectional shape of the bead core 6 is not limited to the above-described embodiment, and may be, for example, a substantially triangular shape so as to expand toward the toe portion 8b inside the tire bead portion as shown in FIG. However, various forms such as a substantially trapezoidal shape are conceivable.
[0018]
As described above, since one bead wire is continuously wound to form the ring-shaped bead core 6 having a shape of two peaks, the productivity of the bead core 6 can be improved, and the tire bead portion inner side can be improved. Of the toe portion 8b.
[0019]
Further, the pneumatic tire provided with the tire bead portion 5 of the present invention is located on the tire bead portion 5, the core body 6a located on the heel portion 8a outside the tire bead portion, and the toe portion 8b located on the inside of the tire bead portion. Since the bead core 6 formed integrally with the protrusion 6b by one bead wire is embedded, the stability and durability of the tire bead 5 can be improved, and the pneumatic radial tire for heavy loads can be used. The durability can also be improved.
[0020]
【The invention's effect】
The present invention is a structure of a tire bead portion formed as a ring-shaped bead core by continuously winding one bead wire as described above, wherein the bead core is located at a heel portion outside the tire bead portion. Since the core body and the projection located at the toe portion inside the tire bead portion are integrally formed, the productivity of the bead core can be improved, and the toe portion inside the tire bead portion can be prevented from jumping up. There is an effect that can be done.
[0021]
In the pneumatic tire provided with the tire bead portion of the present invention, the tire bead portion includes a core body located on the heel portion outside the tire bead portion and a projection located on the toe portion inside the tire bead portion. Since the bead core formed integrally with the bead wire is embedded, the stability and durability of the tire bead can be improved, and the durability of the pneumatic radial tire for heavy loads can be improved. There is.
[Brief description of the drawings]
FIG. 1 is a half sectional view of a pneumatic radial tire for heavy loads embodying the present invention.
FIG. 2 is an enlarged explanatory view of a portion A in FIG. 1;
FIG. 3 is a view similar to FIG. 2 showing another embodiment.
FIG. 4 is a sectional view of a bead portion of a conventional heavy duty pneumatic tire.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pneumatic radial tire 2 Carcass ply 3 Tread part 4 Side wall part 5 Tire bead part 6 Bead core 6a Core body 6b Projection part 7 Tire rim 8a Heel part 8b Toe part X Winding diagram Sa, Sb Bead wire terminal part 11 Carcass Ply 12 Bead section 13 Hexagon bead

Claims (3)

A structure of a tire bead portion formed by continuously winding one bead wire to form a ring-shaped bead core,
The bead core structure, wherein the bead core is formed integrally with a core body located at a heel portion outside a tire bead portion and a projection portion located at a toe portion inside a tire bead portion. The structure of a tire bead portion according to claim 1, wherein the cross-sectional shape of the bead core is formed so as to expand toward the toe portion inside the tire bead portion. At least one or more carcass plies, in a pneumatic tire having a tire bead portion wound around a bead core embedded in a tire bead portion from a tread portion through a sidewall portion,
In the tire bead portion, a bead core in which a core body located on the heel portion outside the tire bead portion and a protrusion located on the toe portion inside the tire bead portion are integrally formed by one bead wire is embedded. A pneumatic tire provided with a tire bead portion.

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