JP3999524B2 - Radial tire for rough terrain - Google Patents

Description

【００２７】
図８及び表１から明らかなように、実験の結果、第１比較例のタイヤ１では、１００ｋｍ／ｈに相当させた転動時においてトレッド部外半径が外膨れを起こした状態下のＤＯＲ（二点鎖線で示したもの）は、同じく２０ｋｍ／ｈに相当させた転動時においてトレッド部外半径が外膨れを起こした状態のＤＯＲ（実線で示したもの）に比して、僅か１０４％以下の変形率」に収まっている。
このようなことから、第１比較例のタイヤ１では、カバープライ１０によってトレッド部２の撓みが適度に抑えられ、高速走行時等（タイヤの空転時を含む）にあって、タイヤ径方向への膨れ変形を抑えることができるとととなる。
【００２８】
そのため、操縦安定性の低下や速度計の表示誤差等は抑制されるものであり、まして車体との接触干渉等は確実に防止される。
これに対し、例えば汎用型バイアスタイヤでは約１０７％の変形率」（汎用型ラジアルタイヤでも約１０５％の変形率」）を示している。
ところで、本発明は、上記した実施形態に限定されるものではなく、実施の形態に応じて適宜変更可能である。
【００２９】
【発明の効果】
以上の説明から明らかなように、本発明に係る不整地走行用ラジアルタイヤでは、カバープライを設けたことによってトレッド部の撓みが適度に抑えられ、高速走行時等にタイヤ径方向への膨れ変形を抑えることができるので、操縦安定性の低下や速度計の表示誤差を防止することができる。
勿論、タイヤがタイヤ径方向への膨れ変形を原因として車体と接触干渉を起こすこともない。
【図面の簡単な説明】
【図１】 本発明に係る不整地走行用ラジアルタイヤの第１比較例を示す要部拡大断面図である。
【図２】 図１のＡ−Ａ線に相当させて層構造を示した断面図である。
【図３】 カバープライにおける螺旋状配置をイメージ的に示した斜視図である。
【図４】 本発明に係る不整地走行用ラジアルタイヤの第２比較例を示す要部拡大断面図である。
【図５】 本発明に係る不整地走行用ラジアルタイヤの第３比較例を示す要部拡大断面図である。
【図６】 本発明に係る不整地走行用ラジアルタイヤの第４比較例を示す要部拡大断面図である。
【図７】 本発明に係る不整地走行用ラジアルタイヤの実施形態を示す要部拡大断面図である。
【図８】 第１比較例の不整地走行用ラジアルタイヤを回転数（走行速度）を変えながら転動させ、その外径の膨れ変形が汎用型バイアスタイヤや汎用型ラジアルタイヤの場合とどれほど抑制されているかを確認するために行った実験の結果である。
【図９】 膨れ変形の測定方法を説明した図である。
【符号の説明】
１ タイヤ（不整地走行用ラジアルタイヤ）
７ カーカスプライ
２ａ トレッド面
８ ブレーカープライ
１０ カバープライ
１４ リボン形素材
１５ コード
２０ ショルダー部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radial tire for running on rough terrain.
[0002]
[Prior art]
Tires for running on rough terrain (generally called ATV tires) were originally formed by bias tires with high envelope performance. Recently, however, the tread has improved rigidity and the side has become less rigid. And a radial tire that is well balanced (see, for example, Japanese Patent No. 2544230, Japanese Patent No. 2690057, Japanese Patent No. 3078589, etc.).
[0003]
[Problems to be solved by the invention]
In the rough terrain traveling tire formed by the radial tire as described above, the strong radial force acting at the time of high speed traveling or the like with the high output of the vehicle causes the tire radial direction (substantially mainly upward). In some cases, the blistering deformation of the material appears remarkably.
If this happens, steering stability may decrease due to the bulging deformation, a display error of the speedometer may occur, and contact interference with the vehicle body may occur in severe cases.
[0004]
The present invention has been made in view of the above circumstances, and is capable of suppressing bulging deformation in the tire radial direction when traveling at high speed (including when the tire is idling). An object of the present invention is to provide a radial tire for traveling on rough terrain that can prevent a decrease in speed, display error of a speedometer, contact interference with a vehicle body, and the like.
[0005]
[Means for Solving the Problems]
Means for solving the problems in the present invention are as follows.
First, the carcass ply 7 is provided at an angle of 0 ° to 15 ° with the radial direction set to 0 °, and between the carcass ply 7 and the tread surface 2a, 60 ° to 80 ° from the radial direction. With breaker ply 8 provided at an angle of
A cover ply 10 having a two- layer structure is provided between the breaker ply 8 and the tread surface 2a.
The cover ply 10 is composed of a ribbon-shaped material 14 formed in a ribbon shape by arranging a plurality of cords 15 side by side, and the ribbon-shaped material 14 maintains an angle of approximately 90 ° with respect to the radial direction. A radial tire for running on uneven terrain, which is wound around the breaker ply 8 along its circumferential direction and is arranged in a spiral shape by being displaced in the tire width direction for each round,
The cover ply 10 has one that covers the breaker ply 8 over its entire width, and one that is provided on the left and right shoulder portions 20;
When the tire internal pressure is a reference pressure, the outer radius of the tread portion 2 during rolling at 100 km / h is 104% or less of the rolling at 20 km / h.
[0006]
Second, the ribbon-shaped material 14 of the cover ply 10 has two or more cords 15 within the ribbon width and the ribbon width is 3 mm or more and 20 mm or less, and is wound along the circumferential direction. The formed ribbon-shaped material 14 is in a contact state in the tire width direction.
That is, the present invention has the following features.
A radial tire for running on rough terrain according to the present invention has a carcass ply provided at an angle of 0 ° to 15 ° with the radial direction set to 0 °, and the above radial is provided between the carcass ply and the tread surface. It has a breaker ply provided at an angle of 60 ° to 80 ° from the direction.
[0007]
The radial direction is the tire width direction. More specifically, it is a direction perpendicular to the tire equator direction on the tread surface.
And the cover ply is provided in the intermediate | middle layer of the depth (embedding depth of thickness direction) in which a breaker ply is provided, and a tread surface.
Here, the cover ply is made of a ribbon-shaped material (material having a ribbon shape), and the ribbon-shaped material keeps an angle of about 90 ° with respect to the radial direction while rotating around the breaker ply. It is arranged in a spiral shape by being wound along the direction and being displaced in the tire width direction every round.
[0008]
With such a configuration, the bending of the tread portion is moderately suppressed by the cover ply, and the bulge deformation in the tire radial direction can be suppressed during high-speed running or the like (including when the tire is idling).
Therefore, it is possible to prevent a decrease in steering stability, a display error of the speedometer, contact interference with the vehicle body, and the like.
The reason for making the ribbon-shaped material an angle of 90 ° with respect to the radial direction is to enable a helical arrangement.
[0009]
The ribbon material of the cover ply preferably has 2 to 20 cords in the ribbon width and the ribbon width is 3 mm to 20 mm.
If the number of cords is only one, the effect of suppressing centrifugal force cannot be obtained sufficiently. If more than 20 cords are used, the cords are not connected due to contact between adjacent ribbon-shaped materials when arranged in a spiral shape. Durability may be reduced and cost may increase.
[0010]
Also, if the ribbon width of the ribbon-shaped material is less than 3 mm, the labor required for the spiral arrangement increases, which adversely affects productivity. If the width exceeds 20 mm, the angle is approximately 90 ° with respect to the radial direction. It becomes difficult to realize.
The extent to which the deflection of the tread portion is suppressed, that is, as a mass standard for providing the cover ply, assuming that the tire internal pressure is the reference pressure, the tread portion outer radius when rolling at 100 km / h is also 20 km / h. It should be 104% or less as compared with the outer radius of the tread when moved.
[0011]
Here, as the reference pressure of the tire internal pressure, for example, about 22.5 kPa may be set.
The cover ply is preferably formed to be 1/2 or more of the dimension in the tire width direction of the breaker ply and has a one-layer or two-layer structure.
On the other hand, the cover ply is provided in a region overlapping with the breaker ply in a one-layer or two-layer structure, or arranged separately on the left and right sides in the tire width direction, and positioned corresponding to the left and right shoulder portions, respectively. It can be provided in a layer structure.
[0012]
Further, the cover ply may have both of these configurations. That is, when it is provided in a region overlapping with the breaker ply, it is provided with a position corresponding to the left and right shoulder portions, and it has a two-layer structure.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show a first comparative example of a rough tire traveling radial tire 1 (hereinafter simply referred to as “tire 1”) according to the present invention. In addition, a comparative example comprises a part of structure of embodiment of the tire 1 which concerns on this invention.
In the tire 1, a carcass ply 7 is provided so as to reach the bead portion 4 from the tread portion 2 through the side portions 3 on both sides thereof, and to wind up around the bead 5 in the bead portion 4. A breaker ply 8 is provided between the carcass ply 7 and the tread surface 2a.
[0014]
When the radial direction of the tire 1 (the same as the tire width direction which is the left-right direction in FIG. 2) is set to 0 °, the carcass ply 7 inclines the material cord in an angle range of 0 ° to 15 ° from this direction. Or provided without tilting.
Further, the breaker ply 8 is provided with the material cord inclined at an angle range of 60 ° to 80 ° from the radial direction. The breaker ply 8 is formed of, for example, a steel cord.
The breaker ply 8 may be a single layer or a plurality of layers.
[0015]
And the cover ply 10 is provided with respect to the intermediate | middle layer of the depth (embedding depth of the thickness direction) in which this breaker ply 8 is provided, and the tread surface 2a. That is, the cover ply 10 is provided between the breaker ply 8 and the tread surface 2a.
The cover ply 10 is formed to be 1/2 or more of the dimension in the tire width direction of the breaker ply 8. In the first comparative example, the cover ply 10 is positioned so as to overlap the breaker ply 8, and is wider than the breaker ply 8.
[0016]
In the first comparative example, only one layer of the cover ply 10 is provided.
As shown in FIG. 3, the cover ply 10 winds a ribbon-shaped material 14 having a ribbon shape along the outer peripheral surface 13 of the green tire 12 on which the breaker ply 8 has been pasted. The ribbon-shaped material 14 is formed by repeatedly shifting the position of the ribbon-shaped material 14 in the tire width direction every time this winding is performed once.
[0017]
Therefore, the ribbon-shaped material 14 is arranged in a spiral shape around the outer peripheral surface 13 of the raw tire 12 as a whole.
In the tire width direction, the gap (see the arrow W in FIG. 3) is held in a portion where the ribbon-shaped material 14 is adjacent to each other in a range that is not wider than the ribbon width of the ribbon-shaped material 14. preferable.
However, in some cases, the ribbon-shaped materials 14 may be brought into contact with each other without causing a gap between adjacent ribbon-shaped materials 14.
[0018]
The ribbon-shaped material 14 is formed by bonding a plurality of cords 15 side by side to form a ribbon shape.
The number of cords 15 forming the ribbon-shaped material 14 is 2 or more and 20 or less.
The ribbon width of the ribbon-shaped material 14 formed in this way is set to 3 mm or more and 20 mm or less.
Therefore, the cover ply 10 formed by the ribbon-shaped material 14 maintains an angle of about 90 ° with the radial direction (that is, a direction substantially parallel to the tire equator direction) as the cord direction.
[0019]
For the cord 15 forming the ribbon-shaped material 14, for example, nylon 6, nylon 66, polyester, rayon, aromatic polyamide or other organic fiber or a combination thereof can be used.
The effect of the tire 1 of the present invention will be described later.
FIG. 4 is an enlarged cross-sectional view of a main part showing a second comparative example of the tire 1 according to the present invention.
The most different point of the tire 1 of the second comparative example from the first comparative example is that the cover ply 10 is formed to be narrower than the breaker ply 8.
[0020]
However, the positional relationship in which the cover ply 10 overlaps the breaker ply 8 and that the cover ply 10 is 1/2 or more of the dimension in the tire width direction of the breaker ply 8 are the same as in the case of the first comparative example.
FIG. 5 is an enlarged cross-sectional view of a main part showing a third comparative example of the tire 1 according to the present invention.
The most different point of the tire 1 of the third comparative example from the first and second comparative examples is that the cover ply 10 is separated to the left and right in the tire width direction.
That is, there is a region where the cover ply 10 is not disposed in the center portion in the width direction of the tread portion 2.
[0021]
The cover plies 10 separated to the left and right are arranged corresponding to the shoulder portions 20 of the tire 1, respectively.
Further, with respect to the left and right cover plies 10, the sum of the dimensions along the tire width direction is ½ or more of the tire width direction dimension of the breaker ply 8.
FIG. 6 is an enlarged cross-sectional view of a main part showing a fourth comparative example of the tire 1 according to the present invention.
In the tire 1 of the fourth comparative example, the cover ply 10 is separated on the left and right in the tire width direction as in the third comparative example.
[0022]
However, the only difference from this third comparative example is that the left and right cover plies 10 are each formed in two layers.
FIG. 7 is an enlarged cross-sectional view of a main part showing an embodiment of the tire 1 according to the present invention.
In the tire 1 of this embodiment, the cover ply 10 is a combination of the arrangement situation shown in the first comparative example (see FIG. 1) and the arrangement situation shown in the third comparative example (see FIG. 5). .
That is, the cover ply 10 of the present embodiment has a positional relationship that overlaps the breaker ply 8 and is wider than the breaker ply 8, and a cover ply 10 that is separated from the left and right in the tire width direction and corresponds to the shoulder portion 20 respectively. These have a two-layer structure.
[0023]
[Experimental example]
8, check is rolled while changing the tire 1 rotating number (speed), swelling deformation of its outer diameter, it is much suppressed as compared with the case of the generic type bias tires and generic type radial tires It is the result of the experiment conducted to do this.
Experiments tire 1 (elected those described in the first comparative example), general-purpose bias tire, and the general-purpose radial tire, after preparing the equivalent of tire sizes, respectively, each adapted to these The test was carried out in a state where it was assembled in a wheel and the tire internal pressure was set to a reference pressure defined for each.
[0024]
The tire size was AT22X7-10.
Tire pressure, in tire 1 and a general-purpose radial tire of the first comparative example was a 22.5KPa, was 20kPa is a general-purpose type bias tires.
As shown in FIG. 9, the method for measuring the swelling deformation is to hold the tire T in a grounded state on the test rotary drum D such as a dynamometer, and the upper half of the tire center position P at this time is the boundary. For the radius (DOR), the amount of change (ΔDOR) during rolling is measured.
[0025]
The same experiment was also performed for AT20X10-9 tire size, and these results are summarized in Table 1.
[0026]
[Table 1]

[0027]
As is apparent from FIG. 8 and Table 1, in the tire 1 of the first comparative example , as a result of the experiment, the DOR (tread portion outer radius is caused to bulge out during rolling corresponding to 100 km / h). The one shown by the two-dot chain line) is only 104% compared to the DOR (shown by the solid line) in the state where the outer radius of the tread portion bulges at the time of rolling equivalent to 20 km / h. The deformation rate is below.
For this reason, in the tire 1 of the first comparative example, the bending of the tread portion 2 is moderately suppressed by the cover ply 10, and when traveling at high speed (including when the tire is idling), the tire radial direction It becomes that it can suppress the swelling deformation.
[0028]
Therefore, a decrease in steering stability, a display error of the speedometer, and the like are suppressed, and contact interference with the vehicle body is reliably prevented.
On the other hand, for example, the deformation rate of about 107% is indicated for the general-purpose bias tire (the deformation rate is about 105% for the general-purpose radial tire).
By the way, the present invention is not limited to the above-described embodiment, and can be appropriately changed according to the embodiment.
[0029]
【The invention's effect】
As is apparent from the above description, in the radial tire for rough terrain travel according to the present invention, the cover ply is provided so that the tread portion is moderately restrained from bending, and the bulge deformation in the tire radial direction during high-speed travel or the like. Therefore, it is possible to prevent a decrease in steering stability and a display error of the speedometer.
Of course, the tire does not cause contact interference with the vehicle body due to bulging deformation in the tire radial direction.
[Brief description of the drawings]
FIG. 1 is an enlarged cross-sectional view of a main part showing a first comparative example of a radial tire for rough terrain travel according to the present invention.
FIG. 2 is a cross-sectional view showing a layer structure corresponding to the line AA in FIG. 1;
FIG. 3 is a perspective view conceptually showing a spiral arrangement in a cover ply.
FIG. 4 is an enlarged cross-sectional view showing a main part of a second comparative example of the radial tire for rough terrain travel according to the present invention.
FIG. 5 is an enlarged cross-sectional view of a main part showing a third comparative example of a radial tire for rough terrain travel according to the present invention.
FIG. 6 is an enlarged cross-sectional view of a main part showing a fourth comparative example of the rough terrain radial tire according to the present invention.
FIG. 7 is an enlarged cross-sectional view of a main part showing an embodiment of a radial tire for rough terrain travel according to the present invention.
FIG. 8 shows how the radial tire for rough terrain travel of the first comparative example rolls while changing the rotation speed (running speed), and how much the bulge deformation of the outer diameter is suppressed as compared with the general-purpose bias tire and the general-purpose radial tire. It is the result of the experiment conducted in order to confirm whether it is carried out.
FIG. 9 is a diagram illustrating a method for measuring swelling deformation.
[Explanation of symbols]
1 tire (radial tire for running on rough terrain)
7 Carcass ply 2a Tread surface 8 Breaker ply 10 Cover ply 14 Ribbon-shaped material 15 Code 20 Shoulder

Claims (2)

It has a carcass ply (7) provided at an angle of 0 ° to 15 ° with the radial direction at 0 °, and 60 ° from the radial direction between the carcass ply (7) and the tread surface (2a). With breaker ply (8) provided at an angle of ~ 80 °,
A cover ply (10) having a two- layer structure is provided between the breaker ply (8) and the tread surface (2a).
The cover ply (10) comprises a ribbon-shaped material (14) formed in a ribbon shape by arranging and joining a plurality of cords (15) . The ribbon-shaped material (14) is substantially in the radial direction. It is wound around the breaker ply (8) along the circumferential direction while maintaining an angle of 90 °, and is displaced in the tire width direction for each lap so that it is arranged in a spiral shape. A radial tire for leveling,
The cover ply (10) has one that covers the breaker ply (8) over the entire width and one that is provided on the left and right shoulder portions (20),
A radial tire for running on uneven terrain, wherein the tread portion during rolling at 100 km / h when the tire internal pressure is a reference pressure and the outer radius is 104% or less of that during rolling at 20 km / h.   The ribbon-shaped material (14) of the cover ply (10) has 2 to 20 cords (15) in the ribbon width, and the ribbon width is 3 mm to 20 mm, along the circumferential direction. The radial tire for rough terrain travel according to claim 1, wherein the wound ribbon-shaped material (14) is in a contact state in the tire width direction.

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