JP4149055B2 - Pneumatic tire with central rib and multiple rows of blocks - Google Patents

Description

【００２６】
【発明の効果】
上記の結果から、本発明によって、乾燥した路面での操縦安定性能に優れ、しかも、濡れた路面を走行したときのブレーキ性能に優れた乗用車用空気入りラジアル・タイヤが得られることことがわかる。
【図面の簡単な説明】
【図１】本発明によるタイヤのトレッド・パターンの一部拡大正面図である。
【図２】本発明によるタイヤのトレッド・パターンの一部拡大正面図である。
【図３】本発明によるタイヤのトレッド・パターンの一部拡大正面図である。
【図４】本発明によるタイヤのトレッド・パターンの一部拡大正面図である。
【図５】本発明によるタイヤのトレッド・パターンの一部拡大正面図である。
【図６】本発明によるタイヤのトレッド・パターンの一部拡大正面図である。
【図７】従来例のタイヤのトレッド・パターンの一部拡大正面図である。
【符号の説明】
１ 中央周方向リブ
２ 中間ブロック列
３ 両側ブロック列
４ 中央周方向溝
５ 両側周方向溝
６１ 袋溝
６２ 溝
６３ 溝
６４ 溝
７１ 傾斜サイプ
７２ 傾斜サイプ
７３ 傾斜サイプ[0001]
[Industrial application fields]
The present invention relates to a pneumatic tire for passenger cars, and in particular, a central circumferential rib disposed in the center of a tread and continuously extending in the tire circumferential direction, and disposed adjacent to both sides of the central circumferential rib. A pair of left and right central circumferential grooves extending continuously in the circumferential direction, a pair of left and right intermediate block rows arranged adjacent to the outside of the central circumferential groove and extending in the tire circumferential direction, and outside the intermediate block row A pair of left and right side circumferential grooves that are arranged adjacent to each other and extend continuously in the tire circumferential direction, and a pair of left and right side block rows that are arranged adjacent to the outside of the both circumferential grooves and extend in the tire circumferential direction. The present invention relates to a pneumatic tire for passenger cars having a tread pattern that is point-symmetric or line-symmetric with respect to the tire equator line.
[0002]
[Prior art]
Conventionally, in a pneumatic tire for a passenger car having a tread pattern composed of a central circumferential rib, an intermediate block row, and both side block rows as described above, when the driving stability performance when traveling on a dry road surface is emphasized A design method is adopted in which the blocks are made relatively large to reduce the sipe as much as possible. On the other hand, when emphasis is placed on icy and snowy road running performance, a design technique is adopted in which edge components are increased by arranging appropriate width and number of grooves and / or sipes.
[0003]
[Problems to be solved by the invention]
If the driving stability performance when driving on a dry road is emphasized and the grooves and / or sipes are reduced as much as possible, the driving performance on ice and snow roads will be extremely reduced, while the driving performance on ice and snow roads will be reduced. Alternatively, when a large number of sipes are provided, the steering stability performance when traveling on a dry road surface is significantly reduced. In other words, steering stability performance on dry road surface and running performance on icy and snowy roads are required performances that are contradictory to each other in pattern design, and has excellent performance on both dry road and icy and snowy roads. Providing tires has been extremely difficult in the past.
[0004]
The object of the present invention is to solve the problems of the prior art as described above, and to have excellent driving stability performance when traveling on a dry road surface, and also for snowy road performance such as braking performance when traveling on a snowy road surface. The present invention also provides an excellent pneumatic radial tire for passenger cars.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a pneumatic tire according to the present invention is disposed at a central portion of a tread and is disposed adjacent to both sides of the central circumferential rib and a central circumferential rib that extends continuously in the tire circumferential direction. A pair of left and right central circumferential grooves extending continuously in the tire circumferential direction; a pair of left and right intermediate block rows arranged adjacent to the outside of the central circumferential groove and extending in the tire circumferential direction; and A pair of left and right side circumferential grooves that are arranged adjacent to the outside and extend continuously in the tire circumferential direction, and a pair of left and right side block rows that are arranged adjacent to the outside of the both sides circumferential groove and extend in the tire circumferential direction In a pneumatic tire having a tread pattern that is point-symmetric or line-symmetric with respect to the tire equator line,
(1) A large number of bag grooves are formed on both sides of the central circumferential rib at intervals in the circumferential direction, and at least one circumferentially adjacent bag groove is provided in the circumferential direction. An inclined sipe extending in an inclined direction is formed,
(2) Each block forming the intermediate block row and the both-side block row is formed with at least one inclined sipe,
(3) The width of the central circumferential rib is 11 to 13% of the grounding width, the width of the intermediate block row is 15 to 17% of the grounding width, and the width of the both side block rows is 15 to 18% of the grounding width. And
(4) When the total sum of the width direction components in the ground contact surface of the central circumferential rib, the intermediate block row, the grooves formed in the both side block rows and the sipe in the ground contact surface is T1, T2, and T3, Is a pneumatic radial tire characterized in that it is 150 to 200% of T1, and T3 is 200 to 350% of T1.
[0006]
In order to achieve the above object, in the pneumatic tire of the present invention,
When the sum of the width direction components in the ground contact surface of the grooves formed in the central circumferential rib, the intermediate block row, and the both side block rows is G1, G2, and G3, G2 is 200 to 200 of G1. 300%, G3 is 200 to 300% of G1, and / or the sum of the widthwise components in the ground plane of the sipe formed in the central circumferential rib, the intermediate block row, and the both side block rows , S2 is preferably 90 to 150% of S1, and S3 is preferably 150 to 300% of S1, where S1, S2 and S3 are respectively set.
[0007]
In order to achieve the above object, in the pneumatic tire of the present invention,
The inclined sipes formed in the both-side block rows are preferably arranged so that the circumferential interval between the inclined sipes and the block ends and the circumferential interval between the adjacent inclined sipes are 6 to 9 mm.
[0008]
In order to achieve the above object, in the pneumatic tire of the present invention,
Calculated as (LL + LR) / 2LC, where the circumferential length of the center of the tire ground contact surface is LC and the circumferential lengths at positions of 80% (40% on one side) from the center to the left and right are LL and LR. It is preferable that the value of the rectangular ratio is 85 to 100% and / or the negative ratio of the tread pattern is 30 to 40% and the hardness of the tread rubber is 55 to 75 degrees.
[0009]
Pneumatic tires are used by being attached to standard rims defined by standards issued by JATMA (Japan), TRA (US), ETRTO (Europe), etc., depending on the size. It is called a rim. In the present specification, in accordance with this common designation, the “regular rim” refers to a standard rim in the application size and ply rating defined in JATMA, ie, JATMA YEAR BOOK issued in 1998 by the Japan Automobile Tire Association.
Similarly, in this specification, “regular load” and “regular internal pressure” mean the maximum load capacity and the maximum load size in the applicable size / ply rating defined in JAMAT YEAR BOOK issued in 1998 by the Japan Automobile Tire Association. Air pressure corresponding to load capacity.
In this specification, “tire contact width” means that a tire is mounted on a regular rim, that is, a standard rim, as defined in JATMA, that is, the Japan Automobile Tire Association, issued in 1998. The maximum linear distance in the axial direction of the tire that can be placed on the contact surface with the flat plate when the load corresponding to the specified mass is statically applied, with the internal pressure being filled and placed perpendicular to the flat plate.
In the case of tires for passenger cars, the “specified internal pressure” is 180 kPa according to the “Measurement method for tires” specified in the JATMA YEAR BOOK issued in 1998 by the Japan Automobile Tire Association. "Load to do" is a mass corresponding to 88% of the maximum load capacity in the applicable size / ply rating.
In this specification, the “tread contact portion” refers to a tread portion that is in contact with a flat plate when the tire contact width is measured.
In the present specification, the “rectangular ratio” is 88% of the maximum load capacity in the applicable size / ply rating, as in the measurement of the “tire contact width” described above, with the tire mounted on a regular rim and filled with an internal pressure of 180 kPa. A load corresponding to the mass corresponding to is statically applied and measured.
In the present specification, the “negative rate” means the ratio of the area of the portion of the apparent tread ground contact area that has a groove or the like but is not actually grounded.
In the present specification, “rubber hardness” refers to rubber hardness measured with a type A durometer in accordance with JIS K 6253 “vulcanized rubber hardness test method”. In addition, when the hardness of the rubber measured with a type A durometer exceeds 90, it is measured with a type D durometer in accordance with the provisions of JIS K 6253 “Vulcanized Rubber Hardness Test Method”. For details, refer to JIS K 6253 “Method for testing hardness of vulcanized rubber”.
[0010]
As described above, the object of the present invention is to provide a passenger car pneumatic that is excellent in driving stability performance when traveling on a dry road surface, and also excellent in snowy road performance such as braking performance when traveling on a snowy road surface. It is to provide radial tires. For tires that require a certain level of performance on ice and snowy roads, handling performance at the time of input with a relatively low lateral G is strongly required among the steering stability performances when traveling on dry road surfaces. The pneumatic tire is configured as described above, and since the central portion in the tire contact surface has fewer lateral grooves and sipes than both sides, the pattern rigidity at the central portion is high and the lateral G is low. Handling performance during input is ensured.
[0011]
Regarding braking performance when running on icy and snowy roads, the contribution of both sides with high contact pressure is large, the pneumatic tire of the present invention is configured as described above, and both sides in the tire contact surface are compared with the center part. Therefore, tires with excellent snow and snow road braking performance can be obtained.
In addition, handling performance when traveling on icy and snowy roads is also an important required performance, but the pneumatic tire of the present invention is configured as described above, and is particularly continuous in the tire circumferential direction. The four main grooves, which are a pair of left and right central circumferential grooves and a pair of left and right circumferential grooves, are arranged, so that there are sufficient circumferential groove components to ensure handling performance when traveling on icy and snowy roads. Has been obtained.
[0012]
Setting the groove means a reduction in tread rubber in that region. When considering the use of a highway main body, the input to the tire is mainly the input in the tire circumferential direction. In this case, generally speaking, the tire center region with the longest contact length will wear out earliest, so the center wear can be reduced by setting the rubber volume in the tire center region larger than in other regions. Can be prevented.
The pneumatic tire of the present invention is configured as described above. In particular, the sum of the width direction components in the ground contact surface of the grooves formed in the central circumferential rib, the intermediate block row, and the both side block rows is G1, When G2 and G3 are set, G2 is 200 to 300% of G1, and G3 is 200 to 300% of G1, so that center wear can be suppressed or prevented.
[0013]
There is concern about the occurrence of uneven wear, so-called heel and toe wear, on both side block rows.
The pneumatic tire of the present invention has the above-described configuration. In particular, the inclined sipe formed in the block blocks on both sides has a circumferential interval between the inclined sipe and the block end and a circumferential interval between adjacent inclined sipes of 6 to 9 mm. Therefore, the step of heel and toe wear can be reduced. If the circumferential interval is greater than 9 mm, heel and toe wear tends to occur remarkably. On the other hand, if it is less than 6 mm, the block rigidity is lowered, and sufficient exercise performance and braking performance cannot be obtained.
[0014]
The tire ground contact shape greatly affects the wear form. The pneumatic tire of the present invention is configured as described above, and in particular, the length in the circumferential direction of the center of the tire contact surface is LC, and the circumferential length at a position of 80% (40% on one side) from side to side. When L is LL and LR, the value of the rectangular ratio calculated by (LL + LR) / 2LC is 85 to 100%, so that the degree of wear of the tread is uniform between the center and both sides of the tire contact surface. Become. When the value of the rectangular ratio is larger than 100%, the region near the shoulder is quickly worn, while when it is smaller than 85%, the center region is quickly worn.
The pneumatic tire of the present invention is configured as described above, and in particular, the tread rubber has a hardness of 55 to 75 degrees, and is dried by providing intermediate properties between a summer tire and a winter tire. Both the feeling of rigidity when traveling on the road surface and the low temperature grip performance when traveling on icy and snowy roads can be achieved. In addition, since the negative rate of the tread pattern is 30 to 40%, both the snowy road performance and the steering stability performance when traveling on a dry road surface are compatible.
In the pneumatic tire of the present invention, since the width of the central circumferential rib is slightly narrower than the width of the intermediate block row and the width of both side block rows, the air excellent in drainage performance at the center portion of the tire contact surface An inset tire is obtained.
When pitch variation is applied to disperse the pattern noise and a pattern having a greatly different block length is produced as a result, the number of sipes may be increased or decreased according to the block length.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, pneumatic tires of Examples 1 to 6 and a conventional pneumatic tire according to the present invention will be described with reference to the drawings. Both tire sizes are 195 / 65R15.
[0016]
The tire according to the first embodiment of the present invention shown in FIG. 1 is disposed adjacent to both sides of a central circumferential rib 1 disposed in the center of the tread and extending continuously in the tire circumferential direction, and the central circumferential rib 1. A pair of left and right central circumferential grooves 4 extending continuously in the tire circumferential direction, a pair of left and right intermediate block rows 2 arranged adjacent to the outside of the central circumferential groove 4 and extending in the tire circumferential direction; A pair of left and right side circumferential grooves 5 which are arranged adjacent to the outside and extend continuously in the tire circumferential direction, and a pair of left and right side block rows 3 which are arranged adjacent to the outside of the both sides circumferential groove 5 and extend in the tire circumferential direction A tread pattern which is symmetrical with respect to the tire equator line E is provided.
A large number of bag grooves 61 are formed on both sides 1 of the central circumferential rib at intervals in the circumferential direction. One bag groove 61 is adjacent to each other in the circumferential direction. An inclined sipe 71 extending in the inclined direction is formed.
Each block forming the intermediate block row 2 is formed with one inclined sipe 72 extending in a direction inclined by 90 degrees with respect to the circumferential direction, and a groove 62 is formed between the blocks forming the intermediate block row 2. Has been.
Each block forming the both-side block row 3 is formed with two inclined sipes 73 extending in a direction inclined by 90 degrees with respect to the circumferential direction, and a groove 63 is formed between each block forming the both-side block row 3. Has been.
The width A of the central circumferential rib 1 is 12% of the ground width, the width B of the intermediate block row 2 is 16% of the ground width, and the width C of the side block rows 3 is 17% of the ground width.
The sum of the width direction components in the ground contact surface of the grooves 61, 62, 63 and the sipes 71, 72, 73 formed in the central circumferential rib 1, the intermediate block row 2, and the both side block rows 3, respectively, is expressed as T1, T2, and When T3, T2 is 164% of T1, and T3 is 267% of T1.
When the sum of the width direction components in the ground contact surface of the grooves 61, 62, 63 formed in the central circumferential rib 1, the intermediate block row 2 and the both side block rows 3 is G1, G2, and G3, respectively, G2 Is 164% of G1, and G3 is 179% of G1.
When the sums of the width direction components in the ground plane of the sipes 71, 72 and 73 formed in the central circumferential rib 1, the intermediate block row 2 and the both side block rows 3 are respectively S1, S2 and S3, S2 Is 164% of S1, and S3 is 357% of S1.
The inclined sipes 73 formed in the both-side block row 3 are arranged so that the circumferential interval between the inclined sipes 73 and the block ends and the circumferential interval between the adjacent inclined sipes 73 are 10 mm.
Calculated as (LL + LR) / 2LC, where the circumferential length of the center of the tire ground contact surface is LC and the circumferential lengths at positions of 80% (40% on one side) from the center to the left and right are LL and LR. The value of the rectangle ratio to be performed is 90%.
The negative rate of the tread pattern is 35%, and the hardness of the tread rubber is 62 degrees.
[0017]
The tire of Example 2 shown in FIG.
The sum of the width direction components in the ground contact surface of the grooves 61, 62, 63 and the sipes 71, 72, 73 formed in the central circumferential rib 1, the intermediate block row 2, and the both side block rows 3, respectively, is expressed as T1, T2, and When T3, T2 is 191% of T1, T3 is 313% of T1, and
When the sum of the width direction components in the ground contact surface of the grooves 61, 62, 63 formed in the central circumferential rib 1, the intermediate block row 2 and the both side block rows 3 is G1, G2, and G3, respectively, G2 Is approximately the same as the tire of Example 1 except that G1 is 230% and G3 is 250% of G1.
[0018]
The tire of Example 3 shown in FIG.
The sum of the width direction components in the ground contact surface of the grooves 61, 62, 63 and the sipes 71, 72, 73 formed in the central circumferential rib 1, the intermediate block row 2, and the both side block rows 3, respectively, is expressed as T1, T2, and When T3, T2 is 167% of T1, T3 is 230% of T1,
When the sum of the width direction components in the ground contact surface of the grooves 61, 62, 63 formed in the central circumferential rib 1, the intermediate block row 2 and the both side block rows 3 is G1, G2, and G3, respectively, G2 Is 230% of G1, G3 is 250% of G1, and
When the sums of the width direction components in the ground plane of the sipes 71, 72 and 73 formed in the central circumferential rib 1, the intermediate block row 2 and the both side block rows 3 are respectively S1, S2 and S3, S2 Is 121% of S1 and S3 is 270% of S1, and is substantially the same as the tire of Example 1 above.
[0019]
The tire of Example 4 shown in FIG.
The sum of the width direction components in the ground contact surface of the grooves 61, 62, 63 and the sipes 71, 72, 73 formed in the central circumferential rib 1, the intermediate block row 2, and the both side block rows 3, respectively, is expressed as T1, T2, and When T3, T2 is 167% of T1, T3 is 230% of T1,
When the sum of the width direction components in the ground contact surface of the grooves 61, 62, 63 formed in the central circumferential rib 1, the intermediate block row 2 and the both side block rows 3 is G1, G2, and G3, respectively, G2 Is 230% of G1, G3 is 250% of G1,
When the sums of the width direction components in the ground plane of the sipes 71, 72 and 73 formed in the central circumferential rib 1, the intermediate block row 2 and the both side block rows 3 are respectively S1, S2 and S3, S2 Is 121% of S1, S3 is 270% of S1, and
The inclined sipes 73 formed on the block blocks 3 on both sides are arranged in such a manner that the circumferential interval between the inclined sipes 73 and the block ends and the circumferential interval between the adjacent inclined sipes 73 are 7 mm. The tire is almost the same as the tire of Example 1.
[0020]
5 and 6 show modified embodiments based on the present invention. In the tires of Examples 1 to 4, the bag groove 61, the groove 62, and the groove 63 extend in a direction inclined by 90 degrees with respect to the circumferential direction. However, as shown in these modified embodiments, the tire according to the present invention may extend in a direction inclined by 50 to 90 degrees with respect to the circumferential direction, and may be an arbitrary curve, that is, a part of an arc or a folding curve. There may be. Moreover, in the tire based on this invention, as shown in the modified example of FIG. 6, you may employ | adopt the sipe extended in parallel with respect to the circumferential direction.
[0021]
The conventional tire shown in FIG.
A central circumferential block row 8 is disposed in place of the central circumferential rib 1 disposed in the center of the tread and continuously extending in the tire circumferential direction;
A lateral groove 64 similar to the groove 62 and the groove 63 is disposed instead of the bag groove 61,
One inclined sipe 73 is formed in each block forming both side block rows 3,
T2 is 133% of T1, T3 is 142% of T1,
G2 is 133% of G1, G3 is 142% of G1,
S2 is 133% of S1, S3 is 142% of S1, and the tire is almost the same as the tire of Example 1 except that the circumferential distance between the inclined sipe 73 and the block end is 15 mm. .
[0022]
For the tires of Examples 1 to 4 and the tire of the conventional example based on the present invention, evaluation tests were conducted on the steering stability performance when running on a dry road and the braking performance when running on snow.
[0023]
Steering stability when driving on dry roads is a wide range of speeds from low speeds to high speeds of around 150km / h on a test course consisting of a high-speed circuit that includes a long straight section and a course-controlled handling evaluation road with many curves. This is the average of the results of two test drivers evaluating the feeling of straight running stability, steering response at the time of steering, road surface grip performance, etc. while driving in a vehicle.
The evaluation test of braking performance when running on snow measures the stopping distance when fully braking from a speed of 40 km / h by leveling a flat straight course with sufficient snow accumulation. It implemented 6 times and evaluated by the average value.
[0024]
The results of the above evaluation test are shown in Table 1 together with an outline of the test tire. The result of the evaluation test is indicated by an index display in which the tire of the conventional example is 100, and the larger the number, the better the performance of the tire.
[0025]
[Table 1]

[0026]
【The invention's effect】
From the above results, it can be seen that the present invention provides a pneumatic radial tire for a passenger car that has excellent steering stability performance on a dry road surface and excellent braking performance when traveling on a wet road surface.
[Brief description of the drawings]
FIG. 1 is a partially enlarged front view of a tread pattern of a tire according to the present invention.
FIG. 2 is a partially enlarged front view of a tread pattern of a tire according to the present invention.
FIG. 3 is a partially enlarged front view of a tread pattern of a tire according to the present invention.
FIG. 4 is a partially enlarged front view of a tread pattern of a tire according to the present invention.
FIG. 5 is a partially enlarged front view of a tread pattern of a tire according to the present invention.
FIG. 6 is a partially enlarged front view of a tread pattern of a tire according to the present invention.
FIG. 7 is a partially enlarged front view of a tread pattern of a conventional tire.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Center circumferential rib 2 Intermediate | middle block row | line | column 3 Both-side block row | line | column 4 Center circumferential direction groove | channel 5 Both-side circumferential groove | channel 61 Bag groove | channel 62 Groove 63 Groove 64 Groove 71 Inclined sipe 72 Inclined sipe 73 Inclined sipe

Claims (6)

A central circumferential rib disposed in the center of the tread and extending continuously in the tire circumferential direction, and a pair of left and right central circumferential grooves disposed adjacent to both sides of the central circumferential rib and continuously extending in the tire circumferential direction And a pair of left and right intermediate block rows arranged adjacent to the outside of the central circumferential groove and extending in the tire circumferential direction, and arranged adjacent to the outside of the intermediate block row and continuously extending in the tire circumferential direction A tread that is point-symmetric or line-symmetric with respect to the tire equator line, comprising a pair of left and right circumferential grooves and a pair of left and right block blocks that are arranged adjacent to the outside of the circumferential grooves and extend in the tire circumferential direction.・ In a pneumatic tire with a pattern,
(1) A large number of bag grooves are formed on both sides of the central circumferential rib at intervals in the circumferential direction, and at least one circumferentially adjacent bag groove is provided in the circumferential direction. An inclined sipe extending in an inclined direction is formed,
(2) Each block forming the intermediate block row and the both-side block row is formed with at least one inclined sipe,
(3) The width of the central circumferential rib is 11 to 13% of the grounding width, the width of the intermediate block row is 15 to 17% of the grounding width, and the width of the both side block rows is 15 to 18% of the grounding width. And
(4) When the total sum of the width direction components in the ground contact surface of the central circumferential rib, the intermediate block row, the grooves formed in the both side block rows and the sipe in the ground contact surface is T1, T2, and T3, Is a pneumatic radial tire characterized by being 150 to 200% of T1 and T3 being 200 to 350% of T1. When the sum of the width direction components in the ground contact surface of the grooves formed in the central circumferential rib, the intermediate block row, and the both side block rows is G1, G2, and G3, G2 is 200 to 200 of G1. The pneumatic radial tire according to claim 1, wherein G3 is 200 to 300% of G1 at 300%. When the sum of the width direction components in the ground contact surface of the sipe formed in the central circumferential rib, the intermediate block row, and the both side block rows is S1, S2, and S3, S2 is 90 to 90 of S1. The pneumatic tire according to claim 1 or 2, wherein S3 is 150 to 300% of S1 at 150%. The inclined sipes formed in the both-side block rows are arranged such that the circumferential interval between the inclined sipes and the block ends and the circumferential interval between the adjacent inclined sipes are 6 to 9 mm. The pneumatic tire according to claim 1. Calculated as (LL + LR) / 2LC, where the circumferential length of the center of the tire ground contact surface is LC and the circumferential lengths at positions of 80% (40% on one side) from the center to the left and right are LL and LR. The pneumatic tire according to any one of claims 1 to 4, wherein a value of the rectangular ratio is 85 to 100%. 6. The pneumatic tire according to claim 1, wherein the tread pattern has a negative rate of 30 to 40% and the tread rubber has a hardness of 55 to 75 degrees.

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