JP4136514B2 - Pneumatic tire - Google Patents

Description

試験の結果から、本発明の適用された実施例のタイヤは、操縦安定性を低下させずに、高速耐久性を向上できていることが分かる。
【００７４】
【発明の効果】
以上説明したように本発明の空気入りタイヤによれば、他性能を犠牲にすることなく高速耐久性を向上することができる、という優れた効果を有する。
【図面の簡単な説明】
【図１】本発明の一実施形態に係る空気入りタイヤのトレッドの断面図である。
【図２】本発明の一実施形態に係る空気入りタイヤのトレッドの平面図である。
【符号の説明】
１０ 空気入りタイヤ
２０ トレッド部
２２ 周方向主溝
２４ 周方向主溝
２６ センターリブ
３０ セカンドブロック
３２ 横溝
３４ ショルダーリブ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pneumatic tire, and particularly to a pneumatic tire excellent in high-speed durability.
[0002]
[Prior art]
Conventionally, the distribution of tread gauges in so-called high performance that emphasizes high-speed driving performance is such that the center land gauge is thicker than the second land gauge, and the shoulder land gauge is larger than the second land gauge. It was about 0.8.
[0003]
Moreover, there existed the following as a prior art for ensuring high-speed durability.
(1) Improved heat resistance of top rubber.
(2) Thinning the entire tread to improve the heat dissipation of the heat accumulated in the rubber.
(3) Improved heat dissipation by adding small grooves and sipes to the land where heat is likely to accumulate.
[0004]
[Problems to be solved by the invention]
However, although the high speed durability is improved in the prior art, there is a problem in that other performance is sacrificed, such as a decrease in motion performance and a deterioration in wear resistance.
[0005]
In view of the above facts, an object of the present invention is to provide a pneumatic tire that can improve high-speed durability without sacrificing exercise performance.
[0006]
[Means for Solving the Problems]
The invention according to claim 1 is a center land portion disposed on the tire equatorial plane, a second land portion disposed on both sides of the center land portion in the tire width direction, and a shoulder disposed facing the shoulder portion. When the tread gauge on the tire equator is G _CL , the tread gauge on the second land is G _2nd , and the tread gauge on the shoulder land is G _sho In addition, G _2nd > G _CL and G _sho / G _2nd = 0.8 to 0.95 are satisfied, mounted on a standard rim, and printed on the tire equatorial plane in a ground contact print under standard internal pressure and standard load. B / a is in the range of 0.60 to 0.80, where a is the circumferential length and b is the circumferential length at 80% of the contact width.
[0007]
Next, the operation of the pneumatic tire according to claim 1 will be described.
[0008]
A ratio (rectangular ratio) b between the circumferential length a at the tire equator and the circumferential length b at 80% of the ground contact width in ground contact printing with standard air pressure and standard load. By setting / a within the range of 0.60 to 0.80, wet steering stability can be ensured.
[0009]
Tires with b / a in the range of 0.60 to 0.80 generally have high heat generation at the center land and the second land, so failure at high speed (tread separation) can also occur at the center land. It often occurs in the part or second land.
[0010]
This tread gauge in the second land portion G _2nd, the tread gauge in the shoulder land portion is taken as G _sho, in the conventional tire, G _sho / G _2nd is about 0.70, the shoulder land portion This is because the load at the time of grounding is small, and the load at the time of grounding is concentrated on the center land part and the second land part.
[0011]
In the pneumatic tire according to claim 1, since G _2nd > G _CL and G _sho / G _2nd = 0.8 to 0.95 are satisfied, the center land portion and the second land are compared with the conventional tire. If it is within the range of G _sho / G _2nd = 0.8 to 0.95, the heat generation at the center land and the second land will be dispersed, which is advantageous for high-speed durability. It becomes.
[0012]
In the present invention, the standard rim is a rim defined by the Yearbook 2002 version of JATMA (Japan Automobile Tire Association), and the standard air pressure corresponds to the maximum load capacity of the Yearbook 2002 version of JATMA (Japan Automobile Tire Association). The standard load is a load corresponding to the maximum load capacity when a single wheel of Year Book 2002 version of JATMA (Japan Automobile Tire Association) is applied.
[0013]
Outside Japan, the load is the maximum load (maximum load capacity) of a single wheel at the applicable size described in the following standard, and the internal pressure is the maximum load (maximum load) of a single wheel described in the following standard. The rim is a standard rim (or “Approved Rim” or “Recommended Rim”) in the applicable size described in the following standards.
[0014]
The standards are determined by industry standards that are valid in the region where the tire is produced or used. For example, it is “The Tire and Rim Association Inc. Year Book” in the United States, and “The European Tire and Rim Technical Organization Standards Manual” in Europe.
[0015]
The invention according to claim 2 is characterized in that in the pneumatic tire according to claim 1, 0.95 ≦ G _CL / G _2nd <1.0 is satisfied.
[0016]
Next, the operation of the pneumatic tire according to claim 2 will be described.
[0017]
By satisfying 0.95 ≦ G _CL / G _2nd <1.0 , the durability of the center land portion can be made equal to the durability of the second land portion.
[0018]
According to a third aspect of the present invention, in the pneumatic tire according to the first or second aspect, the circumferential main groove extending along the tire circumferential direction that defines the center land portion, the second land portion, and the shoulder land portion. The groove depth of the plurality of shoulder lug grooves crossing the shoulder land portion in the tire width direction is 5.0 mm or more.
[0019]
Next, the operation of the pneumatic tire according to claim 3 will be described.
[0020]
A plurality of shoulders crossing the shoulder land portion in the tire width direction with the groove depth of the circumferential main groove extending along the tire circumferential direction defining the center land portion, the second land portion, and the shoulder land portion being 8 mm or more By setting the depth of the lug groove to 5.0 mm or more, high wet drainability can be obtained while ensuring high-speed durability.
[0021]
In addition, the upper limit of the groove depth of the circumferential main groove is 9.3 mm, and the upper limit of the groove depth of the shoulder lug groove is 7.0 mm. If the groove depths of these grooves are too deep, steering stability and the like deteriorate due to a decrease in rigidity of the land portion partitioned by these grooves.
[0022]
According to a fourth aspect of the present invention, in the pneumatic tire according to any one of the first to third aspects, the second land portion is located in a region having a width of 60% of the ground contact width around the tire equator plane. has the contact width CW, width W _CL of the center land portion, the width of the second land portion when the W _2nd, W _CL /CW≧0.1 or a W _2nd /CW≧0.1 It is characterized by being satisfied.
[0023]
Next, the operation of the pneumatic tire according to claim 4 will be described.
[0024]
Since W _CL /CW≧0.1 or W _2nd /CW≧0.1 is satisfied, the rigidity of the center portion of the tread is ensured, and the steering stability is improved.
[0025]
According to a fifth aspect of the present invention, in the pneumatic tire according to any one of the first to fourth aspects, the two-layer steel belts in which the cord directions intersect each other at least immediately below the center land portion, , At least one belt reinforcing layer is provided.
[0026]
Next, the operation of the pneumatic tire according to claim 5 will be described.
[0027]
At least directly below the center land, two layers of steel belts that cross each other in the cord direction and at least one belt reinforcement layer are provided. Can be improved.
[0028]
As the belt reinforcing layer, a cord layer having a cord direction as a circumferential direction is preferable.
[0029]
According to a sixth aspect of the present invention, in the pneumatic tire according to any one of the first to fifth aspects, the tan δ at 0 ° C. of the tread rubber that contacts the road surface is 0.6 to 0.9. It is set within the range of.
[0030]
Next, the operation of the pneumatic tire according to claim 6 will be described.
[0031]
By setting tan δ at 0 ° C. of the tread rubber to be in contact with the road surface within a range of 0.6 to 0.9, high grip performance can be obtained.
[0032]
In general, the larger tan δ, the higher the hysteresis loss and the better the grip. A rubber with a high grip generates a large amount of heat, but by adopting the configuration of the present invention, it is possible to avoid the problem of heat generation when a rubber with a high grip is used.
[0033]
Here, when tan δ is less than 0.6, a high grip required for a high-performance tire cannot be obtained.
[0034]
On the other hand, if tan δ exceeds 0.9, too much heat is generated, and low-temperature embrittlement worsens.
[0035]
The invention according to claim 7 is the pneumatic tire according to any one of claims 1 to 6, wherein the flatness is 50% or less and the tire nominal width is 225 mm or more. .
[0036]
In general, a pneumatic tire having an aspect ratio of 50% or less and a tire nominal width of 225 mm or more is often used for high-speed running because it is resistant to deformation against lateral force and has a high grip. In particular, it can be demonstrated.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
One embodiment of the pneumatic tire of the present invention will be described with reference to FIGS. 1 and 2.
[0038]
As shown in FIG. 1, a pneumatic tire 10 according to this embodiment includes a pair of bead portions 12, a toroidal carcass 14 that extends over both bead portions 12, and both end portions are folded back by bead cores 13. Belt layers 16A and 16B located at the crown portion of the carcass 14, two belt reinforcement layers 18 formed on the belt layer 16B, and a tread portion 20 formed on the belt reinforcement layer 18. The tire has a radial structure.
[0039]
The tire size of the pneumatic tire 10 is 225 / 45ZR17.
[0040]
The belt layers 16A and 16B are formed by arranging steel cords in parallel, and are arranged so as to cross each other.
[0041]
The steel cord of the belt layer 16A has a structure of 1 × 5, the number of shots is 20 / inch, and the angle with respect to the tire equatorial plane CL is 24 °.
[0042]
The steel cord of the belt layer 16B has a structure of 1 × 5, the number of shots is 20 / inch, and the angle with respect to the tire equatorial plane CL is 24 °.
[0043]
The belt reinforcing layer 18 includes a plurality of organic fiber cords. In the present embodiment, nylon having a cord gauge of 0.5 mm is used as the organic fiber cord of the belt reinforcing layer 18, the number of shots is 25 / inch, and the angle with respect to the tire equatorial plane CL is 0 °.
[0044]
The tread rubber constituting the tread portion 20 has a tan δ at 0 ° C. set to 0.8.
[0045]
As shown in FIGS. 1 and 2, the tread portion 20 of the pneumatic tire 10 of the present embodiment has a circumferential direction extending along the tire circumferential direction (arrow A direction and arrow B direction) on both sides of the tire equatorial plane CL. The main groove 22 is formed, and the circumferential main groove 24 is formed on both sides of the circumferential main groove 22 in the tire axial direction (arrow C direction).
[0046]
A center rib 26 continuous in the circumferential direction is provided on the tire equatorial plane CL.
[0047]
Between the circumferential main groove 22 and the circumferential main groove 24, a substantially triangular second block 30 defined by the circumferential main groove 22, the circumferential main groove 24, and the inclined lateral groove 28 is provided.
[0048]
A shoulder rib 34 is provided on the outer side in the tire axial direction of the circumferential main groove 24. The shoulder rib 34 extends from the shoulder side toward the circumferential main groove 24 and terminates in the land portion. Are provided.
[0049]
The pneumatic tire 10 has a designated rotational direction, and is mounted on the vehicle so as to rotate in the direction of arrow A when moving forward.
[0050]
The circumferential main groove 22 has a groove width of 9 to 17 mm and a groove depth of 8.3 mm, and the circumferential main groove 24 has a groove width of 6 to 12 mm and a groove depth of 7.5 mm.
[0051]
The lateral groove 28 has a groove width of 4.5 to 9.0 mm, a groove depth of 7.5 mm, and an angle with respect to the tire equatorial plane CL of 35 to 25 °.
[0052]
The lateral groove 32 has a groove width of 4 to 6 mm, a groove depth of 6.3 mm, and an angle with respect to the tire equatorial plane CL of 10 to 15 °.
[0053]
As shown in FIG. 2, in the present embodiment, the ground contact width CW is 190 mm, the center rib 26 has a width W _CL of 20 mm (constant), the second block 30 has a width W _2nd of 31 mm (maximum width), and the shoulder rib 34 has a width. W _sho is 35 mm (a dimension from the innermost end in the tire width direction to the contact end), and therefore W _CL / CW is 0.105 and W _2nd / CW is 0.16.
[0054]
As shown in FIG. 1, in this embodiment, the tread gauge G _CL at the center rib 26 is 8.7 mm (measured on the tire equatorial plane CL), and the tread gauge G _2nd at the second block 30 is 9.0 ( (Measured at the central portion in the block width direction) mm, tread gauge G _sho at shoulder rib 34 is 8.1 (measured at a position of 80% of ground contact width CW) mm, and therefore G _sho / G _2nd is 0.90. G _CL / G _2nd is 0.97.
[0055]
Further, in the ground contact print when the pneumatic tire 10 of the present embodiment is mounted on a standard rim and used as a standard internal pressure and a standard load, the circumferential length a at the tire equatorial plane CL is 163 mm, and 80% of the ground contact width CW. The circumferential length b (average value on the left and right) at the position is 108.5 mm, and the rectangular ratio b / a is 0.666.
(Function)
Next, the effect | action of the pneumatic tire 10 of this embodiment is demonstrated.
[0056]
In this pneumatic tire 10, the center rib 26 that is continuous in the circumferential direction is provided on the tire equatorial plane CL of the tread portion 20, so that steering stability on a dry road surface, particularly steering response at a small steering angle, is achieved. Can be improved.
[0057]
Since the two steel belts intersecting each other in the cord direction and at least one belt reinforcing layer are provided, the protrusion near the center during high-speed running can be suppressed and high-speed durability can be ensured.
[0058]
In the present embodiment, tan δ at 0 ° C. of the tread rubber is 0.8 and tan δ is set in the range of 0.6 to 0.9, so that high grip performance can be obtained.
[0059]
During wet road running, water in the ground contact surface is drained by the circumferential main grooves 14 and 16 and the lateral grooves 20 and 24.
[0060]
Since the groove depth of the circumferential main groove 22 and the groove depth of the circumferential main groove 24 are each 8 mm or more, and the groove depth of the lateral groove 28 and the groove depth of the lateral groove 32 are each 5 mm or more, High wet drainability can be obtained while ensuring high-speed durability.
[0061]
In contact printing with standard internal pressure and standard load, b / a is 0.60, where a is the circumferential length on the tire equatorial plane and b is the circumferential length at 80% of the contact width. By setting it within the range of 0.80, wet steering stability performance can be ensured.
[0062]
In the pneumatic tire 10 of the present embodiment, G _CL / G _2nd is 0.97, G _sho / G _2nd is 0.90, 0.95 ≦ G _CL / G _2nd <1.0 , and G _sho / Since G _2nd = 0.8 to 0.95 is satisfied, the load concentration on the center rib 26 and the second block 30 can be reduced compared with the conventional tire, and the heat generation of the center rib 26 and the second block 30 is improved. Dispersed to improve high-speed durability.
[0063]
Further, since 0.95 ≦ G _CL / G _2nd <1.0 is satisfied, the durability of the center rib 26 and the durability of the second block 30 can be made equal.
[0064]
In the present embodiment, W _CL /CW=0.105, and a W _2nd /CW=0.16, since satisfied W _CL /CW≧0.1,W _2nd /CW≧0.1, The rigidity of the center portion of the tread portion 20 is ensured, and the steering stability is improved.
[0065]
When the tan δ of the tread rubber is less than 0.6, a high grip required for a high performance tire cannot be obtained.
[0066]
On the other hand, if the tan δ of the tread rubber exceeds 0.9, the heat generation is excessive, and the low temperature embrittlement becomes worse.
[0067]
In addition, each dimension, ratio, etc. which were described in the said embodiment are examples, and it cannot be overemphasized that it can change suitably if it is the range which does not deviate from the meaning of this invention.
(Test example)
In order to confirm the effect of the present invention, a pneumatic tire of a comparative example and a tire of an example to which the present invention was applied were prepared, and a high-speed durability drum test and a steering stability test using an actual vehicle were performed.
[0068]
The patterns of the pneumatic tire used for the test are all the patterns shown in FIG. 2 of the embodiment described above.
[0069]
The pneumatic tire of the example is the tire of the above-described embodiment.
[0070]
As shown in Table 1 below, the tires of Comparative Examples 1 and 2 are the same as the Examples _{except that} the values of G _CL / G _2nd and G _sho / G _2nd are different.
[0071]
High-speed endurance drum test: A test tire was mounted on an indoor drum testing machine and continuously run at a high speed until the tire broke down. The evaluation was expressed as an index with the distance until the tire of Comparative Example 1 failed (tread separation) as 100. The larger the index value, the better the high-speed durability.
[0072]
Steering stability test: A test tire was mounted on an actual vehicle and the test course was run. The evaluation was a feeling evaluation by a professional test driver, and the superiority or inferiority was rated on a 10-point scale.
[0073]
[Table 1]

From the test results, it can be seen that the tire of the example to which the present invention is applied can improve the high-speed durability without deteriorating the steering stability.
[0074]
【The invention's effect】
As described above, according to the pneumatic tire of the present invention, the high-speed durability can be improved without sacrificing other performances.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a tread of a pneumatic tire according to an embodiment of the present invention.
FIG. 2 is a plan view of a tread of a pneumatic tire according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Pneumatic tire 20 Tread part 22 Circumferential main groove 24 Circumferential main groove 26 Center rib 30 Second block 32 Lateral groove 34 Shoulder rib

Claims (7)

A tread comprising a center land portion disposed on the tire equator plane, a second land portion disposed on both sides of the center land portion in the tire width direction, and a shoulder land portion facing the shoulder portion. A tire containing
When the tread gauge on the tire equator is G _CL , the tread gauge on the second land is G _2nd , and the tread gauge on the shoulder land is G _sho , G _2nd > G _CL and G _sho / G _2nd = 0.8-0.95 is satisfied,
Attached to a standard rim, and with a ground contact print under standard air pressure and standard load, when the circumferential length at the tire equatorial plane is a and the circumferential length at 80% of the ground contact width is b b / a is in the range of 0.60 to 0.80,
A pneumatic tire characterized by that. The pneumatic tire according to claim 1, wherein 0.95 ≦ G _CL / G _2nd <1.0 is satisfied. A plurality of shoulder lug grooves that traverse the shoulder land portion in the tire width direction have a groove depth of 8 mm or more in the circumferential main groove extending along the tire circumferential direction that divides the center land portion, the second land portion, and the shoulder land portion. The pneumatic tire according to claim 1 or 2, wherein a groove depth is 6 mm or more. Centering on the tire equator plane, when there is a second land part in the area of 60% of the contact width, the contact width is CW, the center land part is W _CL , and the second land part is W _2nd 4. The pneumatic tire according to claim 1, wherein W _CL /CW≧0.1 or W _2nd /CW≧0.1 is satisfied. 5. The method according to claim 1, wherein at least immediately below the center land portion, two layers of steel belts that cross each other in the cord direction and at least one belt reinforcing layer are provided. The pneumatic tire according to item 1. 6. The tan δ at 0 ° C. of the tread rubber constituting the tread is set within a range of 0.6 to 0.9, according to any one of claims 1 to 5. Pneumatic tire. The pneumatic tire according to any one of claims 1 to 6, wherein a flatness ratio is 50% or less and a tire nominal width is 225 mm or more.

Images