JPH11157309A - Bead ring and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the disturbance of wire layout in a bead core by stacking wire lines circularly wound with a wire having a cross sectional shape formed with circular arc-like recesses at specific places on the peripheral edge section of a circle multiple times in parallel on the outside in the radial direction, and coupling one wire with the recess of the other wire between the wire lines. SOLUTION: A wire 1 has a cross sectional shape formed with circular arc- like recesses at two places on the peripheral edge section of a circle. The wire 1 is circularly wound multiple times in parallel to form wire lines 2, and wire lines 3, 4, 5, 6, 7 are stacked in sequence on the outside in the radial direction of the wire line 2. The wires I are arranged so that the peripheral edge section other than the recesses of the wire 1 of one wire line is coupled with the recess of the wire 1 on the other wire line between adjacent wire lines. The wire peripheral edge sections of adjacent wire lines are coupled with both of two recesses for most of the wires 1 in this bead ring, thereby the binding force between the wires l is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a bead ring and a pneumatic tire to which the bead ring is applied.

[0002]

2. Description of the Related Art A pneumatic tire has a carcass side.
There are various types of bead cores that support the end,
However, the hexagonal bead core structure has excellent shape stability
Is advantageous. That is, as shown in FIG.
A wire W coated with rubber by plating a wire
And wound a plurality of times in parallel to form a wire row W₁ Form
And then this wire row W₁Half the wire W radially outward of
Wire pitch W_TwoStacking
Well, this stack of wire rows is called wire row W_Two, W_Three, W _Four, W
_Five, W₆And W₇ To make the cross-sectional shape hexagonal
When tires are manufactured using trimmed, bead rings,
A bead core having a hexagonal surface is obtained.

[0003] The bead core thus obtained is characterized in that the shape of the bead core is more stable than the so-called strand structure shown in Fig. 2, for example, in which a plurality of steel wires are coated with rubber-coated strands S. It is.

[0004]

However, since the wires constituting the bead core have a circular cross section and the wires are in line contact with each other, the restraining force between the wires is small. Therefore, during the molding and vulcanizing steps of the tire and during the use of the tire, the arrangement of the wires is likely to be disturbed.
If the wire arrangement is disturbed during the tire molding and vulcanization process, the uniformity of the tire will be adversely affected and ride comfort will be impaired. If the wire arrangement is disturbed during use of the tire, the durability of the bead portion will increase. Decreases, causing disadvantages.

[0005] Accordingly, the present invention relates to a tire that does not cause a disturbance in the wire arrangement in a bead core during a tire forming and vulcanizing step, and furthermore, during use of the tire, together with a bead ring suitable for manufacturing the tire. The purpose is to provide.

[0006]

That is, the present invention provides:
Adjacent wires formed by stacking a plurality of wire rows in which a wire having a cross-sectional shape in which an arc-shaped concave portion is formed at two places on the peripheral edge of a circle in a ring and a plurality of times in parallel are arranged radially outside thereof. A bead ring characterized in that a wire of one wire row is engaged with a recess of a wire of another wire row between rows.

[0007] The present invention is also a pneumatic tire having a belt and a tread on a radially outer side of a carcass extending in a toroidal shape between a pair of bead cores, the bead core being formed at a peripheral portion of a circle. A wire having a cross-sectional shape in which an arc-shaped concave portion is formed at a location is formed by stacking a plurality of wire rows in which a plurality of wire rows are wound in a ring and a plurality of times in parallel in a radially outward direction, and one of the adjacent wire rows is stacked. The pneumatic tire is characterized in that a wire of the other wire row is engaged with a recess of the wire of the wire row.

Here, it is advantageous that the radius of curvature in the cross-sectional shape of the concave portion of the wire is 0.25 to 0.75 times the maximum diameter of the wire in order to increase the binding force between the wires.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A bead ring according to the present invention will be described in detail with reference to FIG. That is, the bead ring shown in FIG. 3 winds the wire 1 in an annular shape and a plurality of times in parallel to form a wire row 2, and then shifts the wire 1 radially outward by a half pitch from the wire row 2.
In addition, the number of turns of the wire is increased by one, and the wire row 3 is stacked by winding, and the stacking of the wire row is repeated to form the wire rows 2, 3, 4, and 5, and then the number of turns of the wire is reduced by one. The wire row 6 is formed by stacking the wire rows 6 by reducing the number of turns and by further reducing the number of turns by one to form a hexagonal cross section.

Here, the wire 1 has a cross-sectional shape in which arc-shaped concave portions 1a and 1b are formed at two places on the periphery of a circle. Recesses 1a and 1b of wire 1 of the wire row
In addition, it is important to form a wire arrangement in which the periphery of the other wire row other than the concave portion of the wire 1 is engaged.

More specifically, when the wire 1 is wound with a half pitch shifted radially outward from the wire row 2, the peripheral edges of the wire 1 sequentially fit into the recesses 1 a and 1 b of the wire 1 in the wire row 2. As described above, it is preferable to form the concave portions 1a and 1b of the wire 1. For this purpose, as shown in FIG. 4, when a parallel coordinate system having the axis O as the origin is defined in a cross section orthogonal to the axis O of the wire, a concave portion convex toward the axis O is formed in the adjacent quadrant. 1a and 1b are provided. In other words, the recess 1a
And the quadrant in which the positional relationship between 1b and 1b is point-symmetric with respect to the axis O,
That is, it is desirable that there are no quadrants in the first and third quadrants or in the second and fourth quadrants.

According to the above, a concave portion 1a is formed in a predetermined portion of the wire 1.
And 1b, when the wire 1 is wound around the wire row 2 by a half pitch outward in the radial direction, the peripheral edge of the wire 1 can be fitted into the concave portions 1a and 1b of the wire 1 in the wire row 2.

Here, when each portion of the wires constituting each wire row is counted as "books" for convenience, if the number of wires in the wire row increases radially outward, all the wires 1 constituting the wire row are taken into account. The two wires adjacent in the adjacent wire row are engaged with the concave portions 1a and 1b. In the example of FIG. 3, the wire arrays 2, 3, and 4 correspond to this. On the other hand, when the number of wires in the wire row decreases radially outward, the wires 5a, 5b, 6a, and 6b arranged at the ends of the wire row have concave portions 1a.
And 1b is engaged with the wire of the adjacent wire row. In the example of FIG. 3, the wire rows 5 and 6
Corresponds to this.

In the bead ring according to the present invention, since most of the wires are engaged with both the concave portions 1a and 1b by the peripheral edges of the adjacent wire rows, the restraining force between the wires is reduced by the conventional wire having a circular cross section. Compared to hexagon bead rings, it is significantly improved. Therefore, in a conventional hexagon bead ring,
In order to prevent the collapse of the shape of the wire when wound and formed, rubber coating on the wire was essential, but the bead ring according to the present invention can maintain the desired shape firmly by winding the wire. It is possible to omit the rubber coating. If a rubber-coated wire is used in the present invention, it is needless to say that the slip of the wire can be further suppressed and the gap between the wires can be filled with rubber.

Further, by setting the radius of curvature ρ in the cross-sectional shape of the concave portions 1a and 1b of the wire 1 to be 0.25 to 0.75 times the maximum diameter R of the wire 1 as shown in FIG. It is effective for That is, the radius of curvature ρ is 0.25
If it is less than R, the wire cannot fit in the concave portion, and it is difficult to stably engage the wire of the adjacent wire row. On the other hand, if the radius of curvature ρ exceeds 0.75R, the center of the concave portion becomes unclear, and it is difficult to stably engage the wire of the adjacent wire row with the concave portion.

The size of the recess formed in the wire is as follows:
It is desirable that the length of the arc forming the recess be at least π / 24 · R or more. When the length of the arc is less than π / 24 · R, it becomes difficult to stably engage the wires of the adjacent wire rows as in the case where the radius of curvature of the concave portion is too large.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In trial production of truck and bus tires of size 11R22.5, the structure of which is shown in FIG.
Various bead rings whose structure is shown in FIG. In FIG. 5, reference numeral 8 denotes a bead core, 9 denotes a carcass locked to the bead core 8, 10 denotes a belt for reinforcing a crown portion of the carcass 9, and 11 denotes a tread arranged on the belt 10.

After mounting each tire thus obtained on a standard rim, adjusting the air pressure to 9.00 kgf / cm ² , the load: 32
Under the condition of 15kgf and speed: 60km / h, it was subjected to a continuous drum running test, and the running distance until the tire failed was measured.
The bead durability was evaluated by an index when the running distance of the conventional tire was set to 100. The larger the index is, the more excellent the bead portion durability is.

Further, the manufactured tire was cut in the tread width direction to check whether the shape of the bead core maintained the shape of the bead ring. Table 1 shows the results of these evaluations and the results of the investigation, together with the specifications of the bead ring.

[0020]

[Table 1]

[0021]

According to the bead ring of the present invention, the wire arrangement is not disturbed in the molding and vulcanizing steps of the tire, and the bead core in the product tire is maintained in a desired shape. Provision is possible. Further, since the wire arrangement is not easily disturbed by various external forces applied to the bead core during use of the tire, the durability of the bead portion can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a conventional bead ring having a hexagonal cross section.

FIG. 2 is a perspective view showing a bead ring in which strands are stacked.

FIG. 3 is a sectional view showing a bead ring of the present invention.

FIG. 4 is a sectional view of a wire constituting the bead ring of FIG. 3;

FIG. 5 is a sectional view of a tire.

FIG. 6 is a sectional view of a hexagonal bead ring.

[Explanation of symbols]

 1 Wire 2 Wire Row 3 Wire Row 4 Wire Row 5 Wire Row 6 Wire Row 7 Wire Row 8 Bead Core 9 Carcass 10 Belt 11 Tread

Claims (4)

[Claims] 1. A wire having a cross-sectional shape in which an arc-shaped concave portion is formed at two positions on the periphery of a circle is wound around a plurality of wires in a ring and a plurality of times in parallel. A bead ring wherein a wire of one wire row is engaged with a wire of another wire row between adjacent stacked wire rows. 2. The wire according to claim 1, wherein a radius of curvature of the cross section of the concave portion of the wire is 0.25 to 0.75 of a maximum diameter of the wire.
Bead ring characterized by being twice. 3. A pneumatic tire having a belt and a tread on a radially outer side of a carcass extending in a toroidal shape between a pair of bead cores, wherein the bead cores are formed in two arc-shaped peripheral portions. A plurality of wire rows in which a wire having a cross-sectional shape having a concave portion formed thereon is wound in a ring and a plurality of times in parallel are stacked on a radially outer side thereof, and between adjacent stacked wire rows, a wire of one of the wire rows is formed. The wire of the other wire row is engaged with the concave portion of the pneumatic tire. 4. The wire according to claim 4, wherein the radius of curvature of the cross section of the concave portion of the wire is 0.25 to 0.75 of the maximum diameter of the wire.
A pneumatic tire characterized by a factor of two.