JP4325906B2 - Pneumatic tires for motorcycles - Google Patents

Description

【００３５】
表１の結果より、実施例においては、従来例１および２に比し、全てにおいてバランスよく各性能が向上することが確かめられた。
【００３６】
【発明の効果】
以上説明してきたように、ラジアルカーカス構造の自動二輪車用空気入りタイヤを前後輪両方に装着する組み合わせにおいて、少なくとも前輪または後輪のうちの一方に本発明の自動二輪車用空気入りタイヤを装着することにより、そのスパイラルベルトと角度付きベルトとがもつ優位な特性を活かすことができ、コーナーでの旋回力を含む運動性能、グリップ限界、全般的な車体の振れ挙動の収まり、滑りのコントロール性および路面凹凸吸収性がバランス良く向上して、操縦安定性を高めることができる。
【図面の簡単な説明】
【図１】 本発明の実施の形態に係る自動二輪車用空気入りタイヤの断面図である。
【符号の説明】
１０ 自動二輪車用空気入りタイヤ
１２ カーカスプライ材
１４ ビードコア
１６ ビードフィラー
１８ クラウン部
２２ トレッド
２４ サイドウォール
２６ ベルト層
２６Ａ スパイラルベルト
２６Ｂ 角度付きベルト[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pneumatic tire for a motorcycle, and more particularly to a pneumatic tire for a motorcycle that can improve steering stability by being applied to at least a front wheel or a rear wheel of the motorcycle.
[0002]
[Prior art]
In recent years, as vehicles have become lighter and have higher performance, it has become more important to ensure stability at ultra-high speeds. Thus, from the conventional angled belt structure in which the cord direction has a predetermined angle with respect to the tire equatorial plane, the grounding shape change at high speed is small and the high-speed durability is excellent. A spiral belt structure in the tire circumferential direction has been adopted.
[0003]
Such a spiral belt structure originally has a defect that the tread surface bending rigidity (in the tread width direction) is low, and thus has problems in handling performance such as handling response and low road surface grip force. Therefore, the applicant firstly improved the high-speed durability by adopting a spiral belt structure, and also adopted a cap-base structure in the tread to reinforce the structural flexibility of the spiral belt with a high-strength cap rubber. In addition, a pneumatic tire for a motorcycle that can keep the change in handling performance small by making the hardness of the base rubber lower than that of the cap rubber has been proposed (Japanese Patent Laid-Open No. 2000-177318).
[0004]
In addition, the spiral belt structure made up of only the teal cord to increase the tread bending rigidity becomes too rigid, making it difficult to maintain high ride comfort and slip resistance, and the spiral made up of only the steel cord. If the number of cords to be driven is simply reduced in the belt, there is a detrimental effect on the fatigue resistance of the tread rubber and ply material against repeated bending due to a decrease in fracture strength against air pressure, a decrease in puncture resistance, and a decrease in bending rigidity in the cross-sectional direction. Occurs. In order to solve such a problem, the present applicant has first set an appropriate number of cords to be driven in a spiral structure by combining two types of cords, and can improve air handling stability and other performance. A tire and a manufacturing method thereof have also been proposed (Japanese Patent Laid-Open No. 2002-59707).
[0005]
On the other hand, a radial tire for a motorcycle having at least one layer of an angled belt is also known in addition to the conventional spiral belt, and such a tire is compared with a belt structure having only a spiral belt and no angled belt. Thus, it is known that it is superior in terms of motion performance including turning force at corners and the height of the grip limit.
[0006]
[Problems to be solved by the invention]
However, the conventional combined use of the spiral belt and the angled belt is disadvantageous in general vehicle body swing behavior, slip control and road surface unevenness absorption. In particular, it is known that this tendency becomes stronger in the case of a belt structure having an angled belt as an outer layer of a spiral belt.
[0007]
In order to solve such a problem, measures such as weakening the strength of the cord material of the angled belt, increasing the cord angle with respect to the circumferential direction, and separating the angled belt at the center have been taken. However, such measures cannot optimize the tensile rigidity and bending rigidity in the cross-sectional direction of the belt, and cannot fully bring out the advantages of the angled belt.
[0008]
Therefore, the object of the present invention is to use a spiral belt and an angled belt in combination, taking advantage of the superior characteristics of each belt, exercise performance including turning force at corners, grip limit, and overall vehicle run-out behavior. It is an object of the present invention to provide a pneumatic tire for a motorcycle that can be applied to a front wheel or a rear wheel and has improved controllability of slip, slip control and road surface unevenness absorbability, and improved steering stability.
[0009]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the inventor of the present invention uses a spiral belt and an angled belt structure to reduce the number of driven spiral belts by reducing the center area and increasing the shoulder area. The inventors have found that the above object can be achieved and have completed the present invention. That is, the present invention is as follows.
[0010]
(1) a bead core embedded in a pair of left and right bead portions, a carcass layer straddling in a toroid shape from one bead portion to the other bead portion, and having both end portions wound and locked on the bead core, and the carcass layer In a pneumatic tire for a motorcycle, comprising: a belt layer disposed on the outer side in the tire radial direction of the crown portion; and a tread portion disposed on the outer side in the tire radial direction of the belt layer.
The belt layer includes a spiral belt in which the cord direction is substantially the tire circumferential direction, and two sheets disposed on the outer layer of the spiral belt, and the cord angle is 45 degrees with respect to the tire equatorial plane, in opposite directions. A slanted angled belt, and
Both the cords constituting the spiral belt and the angled belt have an initial tensile resistance of 50 cN / string or more, and the number of spiral belts to be driven is different between the center region and the shoulder region, the center region is small, the shoulder This is a pneumatic tire for motorcycles characterized by an increased area.
[0011]
(2) In the pneumatic tire for a motorcycle according to (1), the center region is assembled on a standard rim defined by JATMA standard, and the tread center is filled with an internal pressure of 80% of the maximum standard internal pressure of the tire. When the shoulder region is a region extending to the tread ends on both shoulder sides excluding the center region, the shoulder region This is a pneumatic tire for motorcycles in which the number of driving is 20% or more higher than the number of driving in the center region.
[0013]
( 3 ) The pneumatic tire for motorcycles according to (1) or (2) , wherein the cord is made of steel, aromatic polyamide or aliphatic polyamide.
[0015]
( 4 ) The pneumatic tire for a motorcycle according to any one of (1) to ( 3 ), wherein the angled belt has a total width of 150 to 70% of a tread width.
[0016]
In the present invention, by keeping the bending rigidity of the center area low by changing the number of spiral belts to be driven, the overall vehicle run-out behavior is mild, and the slip control and road surface unevenness absorbability are kept high. I can leave. This makes it possible to supplement these performances that are reduced by adding an angled reinforcement belt. In addition, the addition of an angled belt can maximize the performance of the corners, including the cornering force due to improved tensile and bending rigidity in the cross-sectional direction, and the height of the grip limit. This increases the degree of structural freedom when applying. As a result of the above, in the present invention, it is possible to easily improve, in a well-balanced manner, exercise performance including cornering turning force, grip limit, general vehicle body swing behavior, slip controllability and road surface unevenness absorbability. This can improve steering stability.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
A pneumatic tire according to an embodiment of the present invention will be described with reference to FIG.
FIG. 1 shows a pneumatic tire 10 for a motorcycle according to the present embodiment. The carcass ply material 12 that constitutes the skeleton of the pneumatic tire 10 is a rubber coating in which organic fiber cords such as nylon and polyester are arranged in parallel. The cord is formed of a plurality of layers arranged in a direction intersecting with the equator plane CL of the pneumatic tire 10 at an angle of 20 to 90 °. Note that the cords of the carcass ply 12 of the plurality of layers intersect with each other and are inclined in opposite directions with respect to the tire equatorial plane CL.
[0018]
In the vicinity of both ends of the carcass ply material 12, a pair of bead cores 14 in which steel wires are wound and bundled in a ring shape are arranged. The carcass ply material 12 straddles the pair of bead cores 14 in a toroid shape, and both ends of the carcass ply material 12 are wound and locked. Further, bead fillers 16 made of hard rubber and formed in a tapered shape are embedded in the gaps between the carcass ply members 12 at the top of the bead core 14.
[0019]
The crown portion 18 of the pneumatic tire 10 is provided with a tread 22 that is formed in an annular shape by a rubber material and is brought into contact with the road surface. A tread pattern (not shown) is appropriately formed on the tread 22. Yes. A sidewall 24 is disposed on a portion of the carcass ply 12 that connects between the bead core 14 and both ends of the tread 22, and an inner liner (not shown) is provided as the innermost layer of the pneumatic tire 10. Is formed.
[0020]
In the present invention, in the pneumatic tire 10 for a motorcycle having the above-described structure, a belt layer 26 described in detail below is disposed between the carcass ply material 12 and the tread portion 22. In the preferred example shown in FIG. 1, as the belt layer 26, two angled belts 26B are disposed on the outer layer of the spiral belt 26A. However, the angled belt 26B is provided on at least the outer layer of the spiral belt 26A. If at least one sheet is disposed, the desired effect of the present invention can be obtained.
[0021]
The spiral belt 26A is formed by spirally winding a long rubber-coated cord (not shown) in which one cord is covered with rubber or a belt-like ply (not shown) in which a plurality of cords are covered with rubber. The cord direction is formed substantially in the tire circumferential direction. In the present invention, the number of driven spiral belts 26A differs between the center region and the shoulder region, the center region is small, and the shoulder region is large. By providing a difference in the number of shots in this manner, the overall vehicle body run-out behavior becomes mild, and slip controllability and road surface unevenness absorbability are improved. These are reduced by adding an angled reinforcing belt 26B. It becomes possible to complement the performance.
[0022]
In order to sufficiently realize such a complementary effect, it is preferable that the center region is assembled on a standard rim defined in the JATMA standard, and both sides from the tread center are in a no-load standard state filled with an internal pressure of 80% of the maximum standard internal pressure of the tire. When the peripheral length of about 1/8 of the peripheral length between the tread ends is an area separated on both sides, and the shoulder area is an area extending to the tread ends on both shoulder sides excluding the center area, the number of shoulder areas driven in Is set to be 20% or more larger than the number of driven center areas.
[0023]
The spiral belt 26A preferably has an initial tensile resistance of 50 cN / string or more from the viewpoints of ensuring the strength of the belt as a belt material and ensuring the reinforcing effect. From some aramids (for example, Du Pont, trade name Kevlar), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), rayon, aliphatic fibers such as nylon, and glass fiber materials. You can choose as appropriate.
[0024]
Next, the two angled belts 26B disposed on the outer layer of the spiral belt 26A maximize the movement performance including the turning force at the corner and the height of the grip limit by improving the tensile rigidity and bending rigidity in the cross-sectional direction. The cord angle is preferably 80 degrees to 20 degrees with respect to the tire equatorial plane. For the same reason, the total width of the angled belt 26B is preferably 150 to 70% of the tread width.
[0025]
The angled belt 26B is a ply in which a plurality of cords arranged side by side are covered with rubber, and is disposed at an angle with respect to the tire equatorial plane. As in the case of the spiral belt 26A, the angled belt 26B preferably has an initial tensile resistance of 50 cN / string or more from the viewpoints of ensuring the strength of the belt as a belt material and ensuring the reinforcing effect. The material can be appropriately selected from the same materials as those for the spiral belt 26A.
[0026]
【Example】
Next, a description will be given below of a running test and a result obtained by comparing the example of the pneumatic tire described in the embodiment and the tire according to the conventional example.
[0027]
Example The pneumatic tire 10 for a motorcycle according to the embodiment shown in Fig. 1 was used as a rear tire. This tire has a size of 190 / 50ZR17, has two nylon carcass plies, and the bead filler has a hardness of 95 ° (Shore A hardness).
[0028]
The spiral belt 26A is composed of one long rubber-coated cord in which a cord of aramid fiber (manufactured by du Pont, trade name Kevlar, twisted structure: 1670 d / 2, initial tensile resistance: 736 cN / piece) is covered with rubber. It was formed by spirally winding. Periphery length of about 1/8 of the peripheral length between the tread center and the tread edge from the tread center in a no-load standard state where the center area is assembled on a standard rim defined by JATMA standard and filled with an internal pressure of 80% of the maximum internal pressure of the tire Are the areas separated from each other on both sides, and the shoulder area is the area extending to the tread ends on both shoulder sides excluding the center area, the number of shoulder area driven is 30/25 mm, and the number of center area driven is 15 / 25 mm.
[0029]
Next, the two angled belts 26B disposed on the outer layer of the spiral belt 26A are aramid fibers (manufactured by du Pont, trade name Kevlar, twisted structure: 1670d / 2, initial tensile resistance: 736cN / fiber ) Cord belt ply (number of driven: 18/25 mm). The cord angle is 45 degrees with respect to the tire equatorial plane. The two angled belts 26B intersect each other and are inclined in opposite directions with respect to the tire equatorial plane CL. The total width of the angled belt 26B is 97% of the tread width.
[0030]
Conventional Example 1
A rear tire similar to the example was used as a test tire except that the number of spiral belts 26A to be driven was constant at 30 pieces / 25 mm in both the center region and the shoulder region.
[0031]
Conventional example 2
A rear tire similar to the example is provided except that the number of spiral belts 26A driven is constant at 30/25 mm in both the center region and the shoulder region, and the cord angle of the angled belt 26B is 15 degrees with respect to the tire equatorial plane. A test tire was used.
[0032]
Each of these tires was mounted on a vehicle as a rear tire, and a running test was performed using conventional tires of size 120 / 70ZR17 as front tires. The results shown in Table 1 below were obtained. Each test result was displayed as an index with the result of Conventional Example 1 being 100 based on the feeling evaluation by the driver. The larger the value, the better the result.
[0033]
The rim size of the front tire used in the running test is MT3.50 × 17, and the rim size of the rear tire is MT6.00 × 17. The tire pressures of the front tire and the rear tire were 250 kPa and 290 kPa, respectively.
[0034]
[Table 1]

[0035]
From the results of Table 1, it was confirmed that in the examples, each performance was improved in a well-balanced manner as compared with the conventional examples 1 and 2.
[0036]
【The invention's effect】
As described above, in a combination in which a pneumatic tire for a motorcycle having a radial carcass structure is mounted on both the front and rear wheels, the pneumatic tire for a motorcycle of the present invention is mounted on at least one of the front wheels or the rear wheels. Can take advantage of the superior characteristics of the spiral belt and the angled belt, the cornering performance including the turning force, grip limit, general vehicle run-out behavior, slip control and road surface The unevenness absorbability can be improved in a well-balanced manner, and steering stability can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a pneumatic tire for a motorcycle according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Pneumatic tire for motorcycles 12 Carcass ply material 14 Bead core 16 Bead filler 18 Crown part 22 Tread 24 Side wall 26 Belt layer 26A Spiral belt 26B Angled belt

Claims (4)

A bead core embedded in a pair of left and right bead portions, a carcass layer straddling in a toroidal shape from one bead portion to the other bead portion, and having both ends wound and locked on the bead core, and a crown portion of the carcass layer In a pneumatic tire for a motorcycle, comprising: a belt layer disposed on the outer side in the tire radial direction of the tire; and a tread portion disposed on the outer side in the tire radial direction of the belt layer.
The belt layer, and a spiral belt cord direction is substantially the tire circumferential direction, two located outside layer of the spiral belt, opposite directions at an angle of cord angle of 45 degrees with respect to the tire equatorial plane An angled belt inclined to
Both the cords constituting the spiral belt and the angled belt have an initial tensile resistance of 50 cN / string or more, and the number of spiral belts to be driven is different between the center region and the shoulder region, the center region is small, the shoulder A pneumatic tire for motorcycles characterized by an increase in area.   Periphery of approximately 1/8 of the peripheral length between the tread center and the tread edge from the tread center in an unloaded standard state in which the center region is assembled on a standard rim defined by JATMA and filled with an internal pressure of 80% of the maximum internal pressure of the tire. When the length is an area separated from each other on both sides and the shoulder area is an area extending to the tread ends on both shoulder sides excluding the center area, the number of shoulder area driven is 20% or more larger than the number of center area driven. The pneumatic tire for a motorcycle according to claim 1.   The pneumatic tire for a motorcycle according to claim 1 or 2, wherein the cord is made of steel, aromatic polyamide or aliphatic polyamide.   The pneumatic tire for a motorcycle according to any one of claims 1 to 3, wherein a total width of the angled belt is 150 to 70% of a tread width.

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