JP2004345603A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of suppressing the drop of the water draining performance in the tread central region as much as practicable, maintaining sufficiently high the rigidity of the crown part of the central region, heightening the maneuvering stability on a dry road surface, and equipping the crown part with excellent resistance against uneven wear. <P>SOLUTION: The pneumatic tire is configured so that circumferentially stretching main grooves 2 are provided in the central region of the tread surface 1 and a plurality of traversing grooves 4 are arranged extending continuously from the road surface side edge E to each main groove 2, and angle-section ridges 7 are formed in the main grooves, wherein the maximum depth of the main grooves 2 is made smaller than that of the traversing grooves, and the skirt part 7a of the ridge 7 is intruded into the traversing groove, and the peak height of the ridge 7 measured from the bottom of the traversing groove is made 85% or less of the maximum depth of the traversing grooves 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００３２】
【表２】

【００３３】
ここで、直進時の耐ハイドロプレーニング性は、水深１０ｍｍのウェット路面を走行時の、ハイドロプレーニング現象の発生速度をフィーリングをもって評価することにより求め、旋回時の耐ハイドロプレーニング性は、水深６ｍｍで半径８０ｍのウェット路面を走行時の、ハイドロプレーニング現象の発生限界での横Ｇを計測することにより求めた。
また、ドライ路面での操縦安定性は、ドライサーキットを各種の走行モードでスポーツ走行したときのテストドライバーのフィーリングをもって評価することにより求めた。
【００３４】
表２によれば、横断面形状が三角山形をなす突条を設けた発明タイヤ１では、とくには直進走行時の耐ハイドロプレーニング性を有効に向上させることができ、横断面形状が台形をなす突条を設けた発明タイヤ２では、旋回走行時の耐ハイドロプレーニング性および、ドライ路面で操縦安定性をとくに大きく向上させ得ることが解る。
【００３５】
【発明の効果】
以上に述べたところから明らかなように、この発明によれば、とくには、トレッド踏面中央域でのウェット排水性の低下を有効に抑制して、その中央域の陸部部分の剛性を大きく高めることができ、これにより、タイヤ全体としてのすぐれた排水性を確保しつつ、ドライ路面での操縦安定性を大きく向上させ、併せて、踏面中央域の陸部部分の耐偏摩耗性をもまた大きく高めることができる。
【図面の簡単な説明】
【図１】この発明の実施の形態を示すトレッドパターンの展開図である。
【図２】図１のＩＩ−ＩＩ線に沿う、山形突条の横断面図である。
【図３】他の実施形態を示す図１と同様の図である。
【図４】図３のＩＶ−ＩＶ線に沿う、図２と同様の断面図である。
【図５】従来タイヤのトレッドパターンの展開図である。
【符号の説明】
１ トレッド踏面
２ 周方向主溝
３ 周方向副溝
４ 横溝
５，６ ブロック列
５ａ ブロック
７ 山形突条
７ａ 裾野部分
７ｂ 突条側壁
Ｅ 踏面側縁
Ｄ 周方向主溝の最大深さ
ｄ 横溝の最大深さ
Ｈ 山形突条のピーク高さ[0001]
TECHNICAL FIELD OF THE INVENTION
This invention improves the rigidity of the land portion in the central area of the tread tread while suppressing the drainage on wet roads, and improves the abrasion resistance and steering stability on dry roads. The present invention relates to a tire, particularly a pneumatic radial tire.
[0002]
[Prior art]
In order to improve drainage on a wet road surface, it is widely and generally practiced to provide a wide circumferential main groove continuous in the tread circumferential direction at the center of the tread tread surface.
However, according to this, since the rigidity of the land portion adjacent to the circumferential main groove is relatively low, the steering stability on a dry road surface is reduced, and uneven wear easily occurs on the land portion. There was a problem.
[0003]
On the other hand, if the cross-sectional area of the circumferential main groove at the center of the tread tread is reduced and the rigidity of the adjacent land part is increased, for the purpose of improving steering stability on dry road surfaces, the tread There is a problem that the drainage property in the central portion is reduced and steering stability on wet road surfaces is impaired.
[0004]
[Problems to be solved by the invention]
The present invention, which focuses on such points, has been made with the object of achieving a high level of compatibility between drainage on wet roads and steering stability on dry roads, which are in a trade-off relationship with each other. The purpose of this is to minimize the drainage in the central area of the tread tread as much as possible and to secure a sufficiently high rigidity in the land area in the central area to improve steering stability on dry road surfaces. It is another object of the present invention to provide a pneumatic tire which has an enhanced uneven wear resistance in a land portion thereof.
[0005]
[Means for Solving the Problems]
The pneumatic tire according to the present invention has at least one or more extending continuously in the central region of the tread tread, for example, on the equator line or at a position slightly offset therefrom, in the circumferential direction of the tread, also in a straight line, a zigzag shape or the like. Along with providing the circumferential main groove, a plurality of lateral grooves continuously extending from at least one tread side edge to the circumferential main groove located closest thereto are arranged at intervals in the tread circumferential direction, A land portion is defined between the circumferential main groove and the lateral groove opening there.The tread circumferentially continuous in the circumferential main groove, for example, having a peak at the center of the width of the main groove. A single ridge is provided, the maximum depth of the circumferential main groove is made shallower than the maximum depth of the lateral groove, and the skirt portion of the ridge is inserted into each horizontal groove opening in the circumferential main groove, The Yamagata ridge The peak heights measured from the lateral groove bottom, in which a 85% or less of the maximum depth of lateral grooves.
[0006]
Here, the tread tread means that the tire is mounted on the applicable rim, filled with the specified air pressure and placed perpendicular to the flat plate, and comes into contact with the flat plate when a mass equivalent to the maximum load capacity is loaded Surface area of the tread rubber.
[0007]
The applicable rim refers to the rim specified in the following standard, and the specified air pressure refers to the air pressure specified corresponding to the maximum load capacity in the following standard, and the maximum load capacity refers to the following. Refers to the maximum mass allowed to be applied to the tire according to the standard. The standard is determined by an industrial standard effective in a region where the tire is manufactured or used. For example, in the United States, "THE TIRE AND RIM ASSOCIATION INC. YEAR BOOK", in Europe, "The European Tire and Rim Technical Organization" STANDARDS MANUAL is the Japan Association of Motor Vehicles, and the OJA is the Japan Association of Motor Vehicles Association (JAR), and the OJA is the Japan Association for Motor Vehicles (OJA), and the OJA is the Japan Association for Motor Vehicles (OJA), and the OJA is the Japan Association for Motor Vehicles.
[0008]
In this tire, drainage on a wet road surface is controlled by one or more circumferential main grooves provided in the central area of the tread tread, which have a high contact pressure and drainage to the front side of the tire and opening in the circumferential main grooves. Each of the lateral drains of the tire due to the lateral grooves provided is sufficiently secured.
[0009]
Also, here, the rigidity of the land portion defined by the circumferential main groove and the lateral groove in the central region of the tread tread is to make the maximum depth of the circumferential main groove shallower than that of the lateral groove, and The skirt portion of the angled ridge formed in the main groove is advantageously increased by each entering the lateral groove opening in the main groove, so in addition to steering stability on a dry road surface, The uneven wear resistance of the land portion can be effectively improved.
[0010]
Moreover, here, by providing the ridges in the circumferential main groove, the rigidity of the land portion can be further increased. Here, the peak height of the chevron measured from the bottom of the lateral groove is set to 85% or less of the maximum depth of the lateral groove. It is intended to ensure sufficient drainage by the groove, and if it exceeds 85%, the groove capacity of the circumferential main groove will be insufficient, and drainage in the center area of the tread, and eventually As a result, the wet drainage performance of the tire as a whole decreases.
[0011]
On the other hand, the Yamagata ridge also functions to assist the active drainage of the water in the central area of the tread tread to the side of the tread and to increase the drainage efficiency. In other words, if the ridges are not provided, most of the water in the central area of the tread will be pushed out to the front side of the tire. It is unavoidable that the drainage efficiency becomes lower because the drainage becomes necessary.
[0012]
More preferably, in such a tire, the peak height of the chevron is 30% or more of the maximum depth of the lateral groove. According to this, it is possible to effectively ensure an increase in the rigidity of the land portion in the central region based on the action of the ridge.
In other words, if it is less than 30%, it is difficult to impart sufficient rigidity to the land portion, and it is therefore difficult to ensure high steering stability and uneven wear resistance.
On the other hand, if it is less than 30%, the drainage efficiency may be reduced.
[0013]
Preferably, the length of the ridges entering the lateral grooves is in the range of 3 to 15% of the tread tread width. With this configuration, the rigidity of the land portion in the center area of the tread can be more effectively increased.
That is, if it is less than 3%, it is difficult to greatly increase the rigidity, while if it exceeds 15%, the groove volume at the center of the tread is insufficient, and the drainage is reduced.
[0014]
In such a tire, in the cross section of the chevron ridge, the extension of the ridge side wall or the midpoint of the periphery of the side wall, that is, between the groove bottom of the circumferential main groove and the top surface or apex of the ridge. The intersection of the tangent at the midpoint of the cross-sectional profile with the normal set on the tread tread profile in the cross-section of the tread, in other words, the normal set on the profile connecting the surface of the tread land part When the angle is in the range of 30 to 70 °, a sufficient volume of the main groove is ensured, and water on the road surface is appropriately introduced into the circumferential main groove with the ridge side wall when the tire is rolling. Can be done.
[0015]
If the angle of intersection is less than 30 °, water flowing along the side wall of the ridge from the top side of the ridge suddenly flows into the lateral groove to generate turbulent flow in the lateral groove, so that drainage may be reduced, If it exceeds 70 °, drainage may be reduced due to insufficient groove volume near the opening end of the lateral groove to the main groove.
[0016]
And preferably, on each side of the circumferential main groove, a pair of circumferential sub-grooves is provided, and each cross-section extends from the side edge of the tread surface so as to intersect with the circumferential sub-groove. Each of the open lateral grooves is provided, and the mutually extending lateral grooves are substantially V-shaped in a front view of the tire.
[0017]
According to this, by the action of the circumferential sub-groove itself, and based on the intersection of the circumferential sub-groove and the lateral groove, drainage can be performed more quickly and smoothly to further improve drainage. it can.
Moreover, here, the respective lateral grooves are extended substantially in a V-shape in a front view, and a directional pattern is formed such that a portion of each lateral groove closer to the circumferential main groove enters the ground plane first. The drainage of the tire to the diagonally forward side can be more reliably performed, and the drainage of the tire can be further enhanced.
[0018]
By the way, when the peak width of the ridge is set in the range of 0 to 10% of the width of the tread tread in the cross section of the ridge, the groove volume of the circumferential main groove is ensured, and the center area of the tread is high. Drainage can be realized. On the other hand, if it exceeds 10%, the groove capacity of the circumferential main groove is insufficient, and it is difficult to ensure high drainage in the center area of the tread.
[0019]
Preferably, the width of the lateral groove is gradually increased from the circumferential sub groove toward the circumferential main groove. According to this, the lateral groove has a sufficiently large lateral groove volume in the vicinity of the opening end to the main groove into which the chevron ridges enter, and, for example, drainage is far more than when the lateral groove width is constant. Can be enhanced.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a developed view of a tread pattern showing an embodiment of a tire according to the present invention.
The internal reinforcement structure of the tire and the like are the same as those of a general radial tire, and are not illustrated here.
[0021]
As shown in this figure, a single circumferential main groove 2 extending linearly and continuously in the tread circumferential direction is provided at the center of the tread tread surface 1 defined above, and each of the circumferential main grooves 2 A pair of circumferential sub-grooves 3 which are located at equal intervals from the main groove 2 and extend linearly in the circumferential direction of the tread, and from the respective side edges E of the tread surface 1 A plurality of transverse grooves 4 intersecting with the circumferential sub-groove 3 and extending continuously to the circumferential main groove 2 are arranged at required intervals in the circumferential direction of the tread, and extend to respective side portions. Each of the lateral grooves 4 is formed in an extended form that is substantially V-shaped when viewed from the front of the tire, and thereby, between the circumferential main groove 2 and the circumferential sub groove 3 and between the circumferential main groove 3 and the circumferential sub groove 3. Two rows of land sections, respectively, between the tread side edge E and the figure To form a block train (5, 6).
[0022]
In addition, as shown in this figure, the extending angle of each lateral groove 4 with respect to the tread circumference increases as the distance from the circumferential main groove 2 increases, and in particular, between the circumferential sub groove 3 and the tread side edge E. This tendency is strengthened, and the width of each lateral groove 4 is made substantially constant over its entire length. However, the extension angle of the former with respect to the tread circumference is determined by the circumferential main groove 2 and the circumferential sub groove 3. , And at least one between the circumferential sub-groove 3 and the tread side edge E, or substantially the entire tread tread surface 1.
It is more preferable that the width of the latter lateral groove 4 be gradually increased from the circumferential sub groove 3 toward the circumferential main groove 2 as described above.
[0023]
By the way, in the illustrated tread pattern, as is apparent from FIG. 2 showing an enlarged cross-sectional view along the line II-II in FIG. A single ridge 7 continuous in the circumferential direction of the tread, in the figure, a triangular ridge is provided, and the maximum depth D of the circumferential main groove 2 after the formation of the ridge 7 is determined by the maximum of the lateral groove 4. The depth d is made shallower than the depth d, and the skirt portion 7a of the chevron ridge 7 is inserted into the lateral groove 4 opening to the main groove 2. Further, the peak height H of the ridge 7 measured from the lateral groove bottom is It is 85% or less of the maximum depth d of the lateral groove 4, more preferably 30% or more.
[0024]
According to this, the rigidity of the block 5 a of each block row 5 formed at a position adjacent to the circumferential main groove 2, particularly in the vicinity of the main groove, determines the maximum depth D of the main groove 2 by the lateral groove 4. And by inserting the skirt portion 7a of the chevron 7 into the lateral groove 4, the chevron itself increases the rigidity of the main groove portion, which greatly increases The drainage in the central area of the tread can be sufficiently ensured by the existence of the circumferential main groove 2 itself and the lateral grooves 4 opened in the main groove 2.
[0025]
These factors can be better balanced by setting the peak height H of the ridge 7 to 85% or less of the maximum depth d of the lateral groove 4, preferably 30% or more. Can be done.
Here, it is preferable that the length of the ridge 7 entering the lateral groove 4 be 3 to 15% of the tread tread width W, and this ratio is determined by the extension angle of the lateral groove 4 with respect to the tread circumference. This can be selected regardless of the length of the lateral groove 4 or the length of the lateral groove 4.
[0026]
Also, as shown in FIG. 2, the intersection angle θ between the extension of the ridge side wall 7b in the cross section of the chevron ridge 7 and the normal N to the tread tread contour in the tread cross section is 30 to It is preferable that the angle be in the range of 70 °.
Here, when the ridge side wall is formed in an arc shape, the intersection angle of the tangent at the midpoint of the periphery of the side wall with the above-mentioned normal line N is set in the range of 30 to 70 °, and the ridge side wall is bent. In the case of a straight line, and in the case of a plurality of circular arcs having different curvatures, it is preferable that the average value of the respective extension line intersection angles or the average value of the plurality of tangent intersection angles be in the range of 30 to 70 °.
[0027]
In addition, according to FIGS. 1 and 2 in which the cross-sectional shape of the chevron ridge 7 is a triangular chevron, the ratio of the peak width of the ridge 7 to the tread tread width W is 0%, but it is the peak width. Even if it has, it is preferable that the ratio to the tread tread width W is 10% or less.
[0028]
FIGS. 3 and 4 are views similar to FIGS. 1 and 2, each showing another embodiment, in which, in the circumferential main groove 2, a ridge 7 having a trapezoidal cross section is provided. The other points are the same as those described above.
Also with such tires, similarly to the above case, it is possible to effectively prevent the drainage of the tread central area from lowering, and to impart high rigidity to the main groove side portion of each block 5a.
[0029]
Although the embodiment of the present invention has been described with reference to the case where the pattern center of the tread pattern is located at the center of the tread tread 1, the present invention offsets the pattern center to any one side of the tread tread center. It is needless to say that the present invention can be applied to the case in which the control is performed.
[0030]
【Example】
A tire for a passenger car having a size of 205/55 R16 and a tread tread width W of 180 mm, the invention tire 1 having the tread structure shown in FIGS. 1 and 2, and the invention tire 2 having the tread structure shown in FIGS. In FIG. 5, each of the conventional tires having a tread structure having no chevron ridges, particularly when the dimensional specifications of the ridges are set as shown in Table 1, the tires attached to the applicable rims , 220kPa air pressure, it is mounted on the actual vehicle, and under the load conditions equivalent to two passengers, on the wet road surface, each hydroplaning resistance during straight running and turning, and on the dry road surface The steering stability was required.
The results are shown in Table 2 with indices. The larger the index value, the better the result.
[0031]
[Table 1]

[0032]
[Table 2]

[0033]
Here, the hydroplaning resistance during straight traveling is determined by evaluating the rate of occurrence of the hydroplaning phenomenon when traveling on a wet road surface with a water depth of 10 mm by feeling. The hydroplaning resistance during turning is 6 mm in water depth. It was determined by measuring the lateral G at the limit of occurrence of the hydroplaning phenomenon when traveling on a wet road surface with a radius of 80 m.
Driving stability on a dry road surface was determined by evaluating the feeling of a test driver when driving a dry circuit in various driving modes in sports.
[0034]
According to Table 2, in the invention tire 1 provided with the ridge having a triangular cross-sectional shape, the hydroplaning resistance, particularly when traveling straight, can be effectively improved, and the cross-sectional shape is trapezoidal. It can be seen that the inventive tire 2 provided with the ridges can significantly improve the hydroplaning resistance during turning and the steering stability on a dry road surface.
[0035]
【The invention's effect】
As is apparent from the above description, according to the present invention, particularly, a decrease in wet drainage in the central region of the tread tread is effectively suppressed, and the rigidity of the land portion in the central region is greatly increased. As a result, while maintaining excellent drainage performance of the tire as a whole, handling stability on dry roads is greatly improved, and at the same time, uneven wear resistance of the land part in the center area of the tread is also improved. Can be greatly increased.
[Brief description of the drawings]
FIG. 1 is a developed view of a tread pattern showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the chevron ridge, taken along line II-II of FIG.
FIG. 3 is a view similar to FIG. 1 showing another embodiment.
FIG. 4 is a sectional view similar to FIG. 2, taken along line IV-IV of FIG. 3;
FIG. 5 is a development view of a tread pattern of a conventional tire.
[Explanation of symbols]
Reference Signs List 1 tread tread surface 2 circumferential main groove 3 circumferential sub groove 4 lateral groove 5, 6 block row 5a block 7 chevron ridge 7a foot portion 7b ridge side wall E tread side edge D maximum depth of circumferential main groove d maximum of lateral groove Depth H Peak height of Yamagata ridge

Claims (7)

In the central area of the tread tread, one or more circumferential main grooves extending continuously in the tread circumferential direction are provided, and at least one tread side edge is continuously connected to the circumferential main groove located closest thereto. A pneumatic tire having a plurality of extending lateral grooves arranged at intervals in a tread circumferential direction,
In the circumferential main groove, a single continuous ridge is provided in the tread circumferential direction, and the maximum depth of the circumferential main groove is made shallower than the maximum depth of the lateral groove,
A pneumatic tire in which a skirt portion of a mountain ridge extends into each lateral groove, and a peak height of the mountain ridge measured from the lateral groove bottom is 85% or less of a maximum depth of the lateral groove. The pneumatic tire according to claim 1, wherein the peak height of the chevron is 30% or more of the maximum depth of the lateral groove. 3. The pneumatic tire according to claim 1, wherein a length of the angled ridge entering the lateral groove is in a range of 3 to 15% of a tread tread width. 4. In the cross section of the chevron ridge, the intersection of the extension line of the ridge side wall or the tangent at the midpoint of the periphery of the side wall with the normal to the tread tread surface contour line in the cross section of the tread is 30 to 70. The pneumatic tire according to any one of claims 1 to 3, which is in a range of °. On each side of the circumferential main groove, a pair of circumferential sub-grooves is provided, and each lateral groove extending from each tread side edge to cross the circumferential sub-groove and opening to the circumferential main groove. The pneumatic tire according to any one of claims 1 to 4, wherein the lateral grooves have a substantially V-shaped extending shape in a front view of the tire. The pneumatic tire according to any one of claims 1 to 5, wherein a peak width of the ridge is in a range of 0 to 10% of a tread tread width in a cross section of the ridge. The pneumatic tire according to any one of claims 1 to 6, wherein the width of the lateral groove is gradually increased from the circumferential auxiliary groove toward the circumferential main groove.

Images