JP4201082B2 - Pneumatic tire - Google Patents

Description

【００３０】
【発明の効果】
上述したように本発明によれば、トレッドにトレッド幅方向のモジュラスＭｗがトレッド厚み方向のモジュラスＭｖよりも大きな特性をもつ異方性ゴムを配置し、前記異方性ゴムとしてトレッド幅方向のモジュラスＭｗとトレッド厚み方向のモジュラスＭｖとの比Ｍｗ／Ｍｖが互いに異なる２種類以上を使用したので、タイヤ幅方向の高モジュラス特性によって高いコーナリングパワーを発生することが可能になり、操縦安定性を向上することができる。また、トレッド厚み方向には低モジュラス特性であるのでエンベロープ性を良好にし、良好な乗心地性を得ることができる。
【図面の簡単な説明】
【図１】本発明の空気入りタイヤの一例を示す子午線方向断面図である。
【図２】本発明の空気入りタイヤのトレッド構造の一例を示すモデル断面図である。
【図３】本発明の空気入りタイヤのトレッド構造の他の例を示すモデル断面図である。
【図４】本発明の空気入りタイヤのトレッド構造の更に他の例を示すモデル断面図である。
【符号の説明】
１ トレッド
２ サイドウォール部
３ ビード部
ａ，ｂ，ｃ，ｄ，ｅ，ｆ ゴム層[0001]
[Technical field to which the invention belongs]
The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire that achieves both steering stability and riding comfort.
[0002]
[Prior art]
As one of the measures for improving the handling stability of the pneumatic tire, it can be considered to increase the rigidity of the tread rubber. However, when the rigidity of the tread rubber is increased, the rubber hardness is increased, and the envelope property of the tread with respect to the road surface is also lowered.
[0003]
That is, the handling stability and riding comfort of pneumatic tires are in conflict with each other, and there is a strong demand to satisfy both of these characteristics at the same time, but no satisfactory complete solution has yet been found.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide a pneumatic tire that solves the above-described conventional problems and makes it possible to achieve both steering stability and riding comfort without inhibiting the tread envelope.
[0005]
[Means for Solving the Problems]
In the pneumatic tire of the present invention that achieves the above object, an anisotropic rubber having a characteristic that the modulus Mw in the tread width direction is larger than the modulus Mv in the tread thickness direction is arranged on the tread, and the tread width is used as the anisotropic rubber. Two or more different ratios Mw / Mv between the direction modulus Mw and the tread thickness direction modulus Mv are used .
[0006]
In this way, an anisotropic rubber having a characteristic in which the modulus Mw in the tread width direction is larger than the modulus Mv in the tread thickness direction is arranged on the tread, and as this anisotropic rubber, the modulus Mw in the tread width direction and the modulus in the tread thickness direction are arranged. Since two or more different Mw / Mv ratios Mw / Mv are used , high cornering power can be generated by having high modulus characteristics in the tire width direction, and steering stability can be improved. Moreover, since it has a low modulus characteristic in the tread thickness direction, the envelope property can be maintained well and good riding comfort can be obtained.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a longitudinal sectional view showing an example of the pneumatic tire of the present invention.
[0008]
In FIG. 1, 1 is a tread, 2 is a sidewall portion, and 3 is a bead portion. The carcass 4 is arranged in the tire so as to reach from the tread 1 to both bead parts 3 and 3 through the side wall parts 2 and 2 on both sides, and the belt layer 5 is provided on the outer peripheral side of the carcass 4 so as to surround the ring. It has been.
[0009]
The pneumatic tire of the present invention uses an anisotropic rubber having a characteristic that the modulus Mw in the tread width direction (that is, the meridian direction) is larger than the modulus Mv in the tread thickness direction for the tread rubber constituting the tread . As the anisotropic rubber, two or more kinds having different ratios Mw / Mv between the modulus Mw in the tread width direction and the modulus Mv in the tread thickness direction are used . The anisotropic rubber having such characteristics may be disposed so as to occupy the entire tread rubber, or may be disposed so as to occupy only a part of the tread rubber.
[0010]
The “modulus” used in the present invention refers to a modulus at 300% elongation measured according to JIS K6301.
[0011]
As described above, when the anisotropic rubber having the characteristic that the modulus Mw in the tread width direction is larger than the modulus Mv in the tread thickness direction is used as a part of the tread rubber, it is preferably illustrated in FIGS. In addition, the tread 1 includes a plurality of rubber layers a, b (FIG. 2); a rubber layer a, b, c, d (FIG. 3); rubber layers a, b, c, d, e. , F, and an anisotropic rubber having the above characteristics may be used for at least two layers in the laminate.
[0012]
The position occupied by the anisotropic rubber in the laminate is not particularly limited. However, in the case of a two-layer structure as shown in FIG. 2, it is preferable to arrange the base rubber in the innermost rubber layer b. Further, in the case of a laminate of 3 layers or more, particularly 4 layers or more, as shown in FIGS. 3 and 4, anisotropic rubber and isotropic rubber may be alternately arranged.
[0013]
In this way, the tread is made into a laminated body of a plurality of rubber layers, and anisotropic rubber and isotropic rubber are alternately arranged in the laminated body, thereby further improving compatibility between driving stability and riding comfort. In addition, the envelope property can be improved. Other isotropic rubbers to be combined with the anisotropic rubber are not particularly limited, but preferably a low modulus rubber having a 300% modulus of 4 to 10 MPa, or measurement conditions of a temperature of 60 ° C., an initial strain of 10%, and an amplitude of ± When the vibration frequency is 2% and the vibration frequency is 20 Hz, it is preferable to use a rubber having a low loss tangent tan δ of 0.03 to 0.3.
[0014]
When the low modulus rubber is combined, the envelope property is improved, and riding comfort and road noise can be further improved. Further, when a low tan δ rubber is combined, rolling resistance can be further improved. These isotropic rubbers may be arranged alternately with anisotropic rubber one layer at a time.
[0016]
As described above, the anisotropic rubber used in the present invention is a rubber having a characteristic that the modulus Mw in the tread width direction (meridian direction) is larger than the modulus Mv in the tread thickness direction, and the modulus Mw in the tread width direction and the tread. Two or more types having different ratios Mw / Mv to the modulus Mv in the thickness direction are used. Preferably, the ratio Mw / Mv of the modulus Mw in the tread width direction to the modulus Mv in the tread thickness direction is 1.2 or more. Each thing should be used. Thus, by using an anisotropic rubber having a ratio Mw / Mv of 1.2 or more, compatibility between steering stability and riding comfort can be further ensured.
[0017]
Moreover, as an anisotropic rubber | gum which satisfy | fills such conditions, the modulus Mw of the tread width direction is 4-20 MPa, and the modulus Mv of the tread thickness direction is 4-20 MPa.
[0018]
The upper limit of the ratio Mw / Mv is not particularly limited, but 5.0 is the limit from the viewpoint of manufacturing possibility. An anisotropic rubber larger than this is difficult to manufacture and has a small elongation, so that the handleability is deteriorated.
[0019]
The anisotropic rubber as described above can be easily obtained by mixing the short fibers in the rubber so as to be arranged in the direction in which the high modulus Mw is generated. As a method for producing such an anisotropic rubber, short fibers may be blended with unvulcanized rubber and extruded into a plate shape while being kneaded in an extruder. Since the short fibers are arranged in parallel in the extrusion direction in the extruded rubber sheet, the anisotropy that increases the modulus in the arrangement direction of the short fibers and decreases the modulus in the thickness direction perpendicular thereto. Present. Therefore, when this plate-like rubber is molded as a tread rubber of a tire, it may be molded so that the extrusion direction is the tread width direction and the thickness direction is matched with the tread thickness direction.
[0020]
The type of short fiber is not particularly limited. For example, organic fiber such as polyamide fiber, polyester fiber, PVA fiber, polypropylene fiber, polyethylene fiber, polyacryl fiber, and aramid fiber, inorganic fiber such as glass fiber and carbon fiber, Examples thereof include natural fibers such as cotton and hemp. The thickness of the short fiber is preferably 0.5 to 15 dtex in terms of single yarn fineness and 3 to 50 mm in length.
[0021]
The present invention is preferably applied to a pneumatic radial tire, but is naturally applicable to a pneumatic tire such as a bias tire.
[0022]
【Example】
The cornering power (CP) and riding comfort used for evaluation in the examples described below were measured by the following measuring methods.
[0023]
Cornering power (CP):
CP was measured with a drum tester at a load of 4 kN, a slip angle of 1 °, and a running speed of 10 km / h. The evaluation was shown by an index with the measured value of the conventional tire (Comparative Example 2 ) as 100. A larger index means a larger CP.
[0024]
Ride comfort:
Evaluation was made by a 10-point method based on a sensory test with five test drivers, and the average value of the five was shown as an index with the conventional tire (Comparative Example 2 ) as 100. A larger index means better ride comfort.
[0025]
Comparative Example 1
The tire size is 235 / 45ZR17, and the tread has the two-layer structure shown in FIG. 2, and the upper cap rubber and the lower base rubber have a 300% modulus Mw in the tread width direction and a tread thickness direction, respectively. A pneumatic radial tire in which an isotropic rubber having 300% modulus Mv and an anisotropic rubber were arranged was manufactured.
Cap rubber Mw = 11.1MPa, Mv = 11.1MPa
(Mw / Mv = 1.0)
Base rubber Mw = 15.5MPa, Mv = 11.1MPa
(Mw / Mv = 1.4)
When the cornering power (CP) and riding comfort of the obtained tire were measured, the results shown in Table 1 were obtained.
[0026]
Comparative Example 2
A pneumatic radial tire having a conventional structure having the same configuration as that of Comparative Example 1 was produced except that the tread had a single layer structure and the same isotropic rubber as the cap rubber of Comparative Example 1 was used as the tread rubber.
When the cornering power (CP) and riding comfort of the obtained tire were measured, the results shown in Table 1 were obtained.
[0027]
Comparative Example 3
The tread has a six-layer structure shown in FIG. 4, the same isotropic rubber as the cap rubber of Comparative Example 1 is used as the rubber layers b, d, and f in FIG. 4, and the same anisotropic rubber as the base rubber is used as the rubber shown in FIG. A pneumatic radial tire having the same configuration as that of Comparative Example 1 was manufactured except that the layers were arranged in the layers a, c, and e, respectively.
When the cornering power (CP) and riding comfort of the obtained tire were measured, the results shown in Table 1 were obtained.
[0028]
Example 1
The tread has a two-layer structure shown in FIG. 2, and anisotropic rubber having 300% modulus Mw in the tread width direction and 300% modulus Mv in the tread thickness direction is arranged on the cap rubber and the base rubber, respectively. Except for the above, a pneumatic radial tire having the same configuration as Comparative Example 1 was produced.
Cap rubber Mw = 15.5 MPa, Mv = 8.1 MPa
(Mw / Mv = 1.8)
Base rubber Mw = 15.5MPa, Mv = 11.1MPa
(Mw / Mv = 1.4)
When the cornering power (CP) and riding comfort of the obtained tire were measured, the results shown in Table 1 were obtained.
[0029]
[Table 1]

[0030]
【The invention's effect】
As described above, according to the present invention, an anisotropic rubber having a characteristic that the modulus Mw in the tread width direction is larger than the modulus Mv in the tread thickness direction is arranged on the tread, and the modulus in the tread width direction is used as the anisotropic rubber. Using two or more different Mw / Mv ratio Mw / Mv ratio Mw / Mv in the tread thickness direction makes it possible to generate high cornering power due to high modulus characteristics in the tire width direction and improve steering stability. can do. Further, since it has a low modulus characteristic in the tread thickness direction, it is possible to improve the envelope property and obtain a good riding comfort.
[Brief description of the drawings]
FIG. 1 is a meridional direction sectional view showing an example of a pneumatic tire of the present invention.
FIG. 2 is a model sectional view showing an example of a tread structure of a pneumatic tire according to the present invention.
FIG. 3 is a model cross-sectional view showing another example of the tread structure of the pneumatic tire of the present invention.
FIG. 4 is a model sectional view showing still another example of the tread structure of the pneumatic tire of the present invention.
[Explanation of symbols]
1 Tread 2 Side wall part 3 Bead part a, b, c, d, e, f Rubber layer

Claims (7)

An anisotropic rubber having a characteristic that the modulus Mw in the tread width direction is larger than the modulus Mv in the tread thickness direction is arranged on the tread, and the modulus Mw in the tread width direction and the modulus Mv in the tread thickness direction are used as the anisotropic rubber. A pneumatic tire using two or more types having different ratios Mw / Mv . 2. The pneumatic tire according to claim 1, wherein the tread is configured by a laminate including a plurality of rubber layers, and at least two layers in the laminate are the anisotropic rubber.   The pneumatic tire according to claim 2, wherein the base rubber in the laminate is the anisotropic rubber. The pneumatic tire according to claim 2 or 3, wherein the anisotropic rubber and the isotropic rubber are alternately arranged in the laminate. The pneumatic tire according to claim 1 ratio Mw / Mv and modulus Mv modulus Mw and the tread thickness direction before Quito Red width direction is 1.2 or more. Before modulus Mw Quito Red width direction is 4～20MPa, pneumatic tire according to claim 1 wherein the tread thickness direction modulus Mv is 4～20MPa. The pneumatic tire according to any one of 請 Motomeko 1-6 mixed to arrange the short fibers in the tread width direction in the anisotropic rubber.

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