JP4743991B2 - Pneumatic tire - Google Patents

Description

【００１８】
【表２】

【００１９】
表２を見れば、各実施例は、何れも、３００００ｋｍを完走して、連続走行距離が従来例よりも長いと共に、上記完走後も外観損傷、内面損傷がないことが分かる。
【００２０】
又、各実施例と従来例の高速性能、実車性能、タイヤ強度の各試験を行った。試験結果を次の表３に示す。尚、表３において、高速性能、実車性能の従来例比とは、従来例を各実施例と同一条件で試験した際の試験結果と、各実施例の試験結果との比を示している。又、タイヤ強度は、目視により、判定した。
【００２１】
【表３】

【００２２】
表３を見れば、各実施例は、何れも、高速性能、実車性能が、従来例よりも優れていると共に、タイヤ強度も合格レベルに達していることが分かる。
【００２３】
尚、実施の形態は、本発明を高荷重空気入りラジアルタイヤに適用したものであるが、本発明は、その他の空気入りラジアルタイヤや空気入りタイヤ等にも適用可能である。
【００２４】
【発明の効果】
以上詳述したように、本発明によれば、ビード部付近の損傷や、内側カーカスプライの巻上部における、半径方向の外端縁付近からのセパレーション等の発生を防止でき、耐久性を向上できる。又、ビードフィラーと各プライの巻上部間に、スチールレインフォースを配設したり、或いは、ビードフィラーとして、極太なものを採用したりする必要がなく、タイヤの製造コストの上昇やタイヤ重量の増加を招来する惧れもない。更に、走行安定性を良好にできると共に、外側カーカスプライの巻上部における、半径方向の外端縁や、トレッド部とサイドウォール部の境界部分からのセパレーションやクラック等の発生を防止できて、耐久性を良好なものとできる。
請求項２によれば、走行安定性を良好にできると共に、タイヤの屈曲性も良好とできて、乗り心地を良好なものとできる。
【図面の簡単な説明】
【図１】本発明の実施の形態の一例を示す断面図である。
【図２】従来一例を示す断面図である。
【図３】従来の他の例を示す断面図である。
【図４】従来の他の例を示す断面図である。
【符号の説明】
１ トレッド部
２ サイドウォール部
３ ビード部
４ ビードコア
５ カーカス
７，８ 内側・外側カーカスプライ
７Ａ，８Ａ 本体部
７Ｂ，８Ｂ 巻上部
７Ｃ，８Ｃ 外端縁
９ ビードフィラー
９Ｃ 外端縁
１１ タイヤの最大幅部位
ＢＬ ビードベースライン[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pneumatic tire such as a pneumatic radial tire.
[0002]
[Prior art]
As a pneumatic radial tire, as shown in FIG. 2, a carcass 21 has a two-ply configuration including an inner carcass ply 22 and an outer carcass ply 23 disposed on the outer side thereof. The body portions 22A and 23A extending from the tread portion 24 through the sidewall portion 25 to the inside of the bead core 27 of the bead portion 26 in the tire axial direction, and the winding wound around the bead core 27 from the inner side in the tire axial direction to the outer side. What has the upper part 22B and 23B, and the bead filler 28 extended radially outward from the bead core 27 between the main body part 22A of the inner carcass ply 22 and the winding upper parts 22B and 23B of both the plies 22 and 23 is disposed. is there.
[0003]
By the way, in the above-mentioned conventional one, the bead base line of the outer end edge 22C in the radial direction in the winding part 22B of the inner carcass ply 22 (in this specification, the “bead base line” is defined by JIS. It is defined as a reference line in the tire axial direction on the bead side that defines the tire cross-section height.) Height from BL 2TOP was 18 to 20 mm, and the outer edge 22C was in the vicinity of the rim flange 29 in the radial direction.
[0004]
[Problems to be solved by the invention]
The external force from the rim flange 29 acts almost directly (substantially as it is) near the outer edge 22C of the inner carcass ply 22 during traveling. For this reason, in a high-load tire having a road index (LI) of 110 or more, the external force from the rim flange 29 acting on the outer end edge 22C during traveling is large, resulting in damage near the bead portion 26 and Separation or the like from the vicinity of the end edge 22C is likely to occur, and there is a problem in durability.
[0005]
In order to solve this problem, in a high-load tire, as shown in FIG. 3, a steel reinforcement 30 is disposed between the bead filler 28 and the upper portions 22B and 23B of both plies 22 and 23, or As shown in FIG. 4, a very thick bead filler 28 is employed.
[0006]
In the above, damage near the bead portion 26 can be reliably prevented, but separation from the outer end edge 22C of the inner carcass ply 22 cannot be prevented, and there is still a problem in durability. is there. In addition, the above-described one has a disadvantage that it causes an increase in tire manufacturing cost and an increase in tire weight.
[0007]
An object of the present invention is to provide a pneumatic tire capable of solving the above problems.
[0008]
[Means for Solving the Problems]
To achieve the above object, it is an aspect of the present invention, the carcass is, has an inner Kakasupura Lee tire tread side, the tire inner surface side outer Kakasupura Lee, each ply, sidewall portion from a tread portion A body part extending from the inside of the bead core to the inside of the tire axial direction and a winding part wound around the bead core from the inside to the outside of the tire axial direction. In the pneumatic tire in which a bead filler extending radially outward from the bead core is disposed between the winding parts, the height from the bead baseline of the radially outer edge at the winding part of the inner carcass ply is 42 mm. or more, and, in the bead filler is less than 90% the height of from the radial outer edge of the bead base line, the outer In roll-up portion of Kasupurai, height from the radial outer edge of the bead base line, from the bead base line to a point that is a 100 to 110% of the height of the maximum width portion of the tire.
Incidentally, in the bi Dofira height from the radial outer edge of the bead base line, also it is a 60% to 95% of the height from the bead base line to the maximum width portion of the tire.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of an embodiment in which the present invention is applied to a high-load pneumatic radial tire having a load index (LI) of 110 or more will be described with reference to the drawing of FIG. 1. FIG. It has a tread portion 1, a sidewall portion 2 and a bead portion 3 addressed to a pair of left and right, and the overall shape is a toroidal shape. A bead core 4 having a quadrangular section is embedded in the bead portion 3 in a ring shape, and a carcass 5 is disposed between the left and right bead portions 3. 6 is a rim flange, 13 is a belt layer, and has two belt plies 14 and 15.
[0010]
The carcass 5 has a two-ply structure including an inner (NO.2) carcass ply 7 on the tire tread surface side and an outer (NO.1) carcass ply 8 on the tire inner surface side . Each ply 7, 8 is made of a metal cord, an organic fiber cord, etc., and main body portions 7 A, 8 A extending from the tread portion 1 through the sidewall portion 2 to the inner side in the tire axial direction of the bead core 4 of the bead portion 3, and the bead core 4. The upper part 7B and the upper part 8B are folded back and rolled up from the inner side in the tire axial direction. A bead filler 9 having a triangular cross section (wedge shape) extending radially outward from the bead core 4 is disposed between the main body portion 7A of the inner carcass ply 7 and the winding portions 7B, 8B of both plies 7, 8. The filler 9 is made of hard rubber.
[0011]
And the position of the outer edge (upper edge) 7C, 8C, 9C of the radial direction in the winding part 7B, 8B of each ply 7, 8 and the bead filler 9 is set as follows. That is, the height NO. Of the outer end edge 7C in the radial direction from the bead base line BL in the upper part 7B of the inner carcass ply 7 2TOP is 25 mm or more and 90% or less of the height BFTOP of the bead filler 9 from the line BL of the outer edge 9C in the radial direction. Height NO. 2TOP may be 40 or 42 mm or more.
[0012]
By the way, height NO. If 2TOP is lower than 25 mm, it cannot withstand the external force applied from the rim flange 6 near the outer edge 7C of the inner carcass ply 7 during traveling. As a result, damage near the bead portion 3 or from the vicinity of the outer edge 7C. Such a separation is likely to occur, and there is a problem in durability. Also, height NO. When 2TOP is higher than 90% of the height BFTOP, the outer end edges 7C and 9C of both the inner carcass ply 7 and the bead filler 9 approach each other, and stress tends to concentrate on the outer end edges 7C and 9C during traveling, As a result, separation from the outer end edges 7C and 9C is likely to occur, and there is a problem in durability.
[0013]
The height NO. Of the outer end edge 8C in the radial direction from the bead base line BL in the upper part 8B of the outer carcass ply 8 is also shown. 1 TOP is defined as 100 to 110% of the height MSH from the line BL to the maximum width portion (location, position) 11 of the tire. Height NO. When 1 TOP is lower than 100% of the height MSH, running stability is deteriorated. Also, height NO. When 1 TOP is higher than 110% of the height MSH, the outer edge 8C approaches the boundary portion between the tread portion 1 and the sidewall portion 2, and stress tends to concentrate on the boundary portion and the outer edge 8C during traveling. As a result, separation, cracks, and the like from the boundary portion and the outer edge 8C are likely to occur, and there is a problem in durability.
[0014]
Further, the height BFTOP from the bead base line BL of the outer edge in the radial direction in the bead filler 9 is set to 60 to 95% of the height MSH from the line BL to the maximum width portion 11 of the tire. When the height BFTOP is lower than 60% of the height TMSH, the running stability is deteriorated. On the other hand, if the height BFTOP is higher than 95% of the height MSH, the flexibility of the tire is deteriorated and the ride comfort is deteriorated.
[0015]
【Example】
Hereinafter, the present invention will be further described with reference to examples in which the present invention is implemented and conventional examples, but the present invention is not limited to the examples.
[0016]
First, based on the specifications (structure) shown in the following Table 1, each example and conventional example are manufactured, and these are run at a constant speed under a high load load by an indoor drum, and durability is tested. did. Table 2 below shows the load, speed, and room temperature conditions during the test, and the continuous travel distance, appearance damage, and internal damage as test results. In Table 2, the ratio of continuous running distance to the conventional example is the continuous running distance when the conventional example is tested under the same conditions as the respective examples (the continuous running distance until the vehicle cannot run due to appearance damage and / or internal damage). ) And the travel distance of each example.
[0017]
[Table 1]

[0018]
[Table 2]

[0019]
From Table 2, it can be seen that each Example completed 30000 km, the continuous travel distance was longer than that of the conventional example, and there was no appearance damage or inner surface damage after the completion.
[0020]
Further, high speed performance, actual vehicle performance, and tire strength tests of each example and the conventional example were performed. The test results are shown in Table 3 below. In Table 3, the ratio of the conventional example of the high speed performance and the actual vehicle performance indicates the ratio of the test result when the conventional example is tested under the same conditions as each example and the test result of each example. The tire strength was determined visually.
[0021]
[Table 3]

[0022]
As can be seen from Table 3, in each of the examples, the high speed performance and the actual vehicle performance are superior to those of the conventional example, and the tire strength has also reached an acceptable level.
[0023]
In the embodiment, the present invention is applied to a high-load pneumatic radial tire, but the present invention can also be applied to other pneumatic radial tires, pneumatic tires, and the like.
[0024]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to prevent the occurrence of damage near the bead portion or separation from the vicinity of the outer edge in the radial direction at the winding portion of the inner carcass ply, and the durability can be improved. . Moreover, it is not necessary to arrange a steel reinforcement between the bead filler and the upper part of each ply, or to use a very thick bead filler, which increases the tire manufacturing cost and the tire weight. There is no risk of an increase. In addition, the running stability can be improved, and it is possible to prevent the occurrence of separation and cracks from the outer edge in the radial direction and the boundary between the tread and sidewalls at the upper part of the outer carcass ply. The property can be improved.
According to claim 2, in co-when the running stability can be well, made tires of flexibility also good, can ride comfort good.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a conventional example.
FIG. 3 is a cross-sectional view showing another conventional example.
FIG. 4 is a cross-sectional view showing another conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 3 Bead part 4 Bead core 5 Carcass 7, 8 Inner side / outer carcass ply 7A, 8A Body part 7B, 8B Winding part 7C, 8C Outer edge 9 Bead filler 9C Outer edge 11 Maximum tire width Location BL Bead Baseline

Claims (2)

The carcass 5 has an inner carcass ply 7 on the tire tread surface side and an outer carcass ply 8 on the tire inner surface side, and each ply 7, 8 passes from the tread portion 1 through the sidewall portion 2 to the bead core 4 of the bead portion 3. Main body portions 7A and 8A extending inward in the tire axial direction, and winding portions 7B and 8B that are turned up around the bead core 4 from the inner side in the tire axial direction and wound up. In the pneumatic tire in which the bead filler 9 extending radially outward from the bead core 4 is disposed between the upper portions 7B and 8B of the plies 7 and 8,
The height NO. Of the outer edge 7C in the radial direction from the bead base line BL at the upper part 7B of the inner carcass ply 7 is shown. 2TOP is 42 mm or more and 90% or less of the height BFTOP from the bead base line BL of the outer edge 9C in the radial direction in the bead filler 9 ;
The height NO. Of the outer edge 8C in the radial direction from the bead base line BL at the upper part 8B of the outer carcass ply 8 is shown. A pneumatic tire in which 1 TOP is 100 to 110% of the height MSH from the bead base line BL to the maximum width portion 11 of the tire. The height BFTOP from the bead base line BL of the radially outer edge 9C of the bead filler 9 is 60 to 95% of the height MSH from the bead base line BL to the maximum tire width portion 11. The pneumatic tire according to 1.

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