JP2009255867A - Pneumatic tire with tread pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire with a tread pattern capable of reducing a rolling resistance by a method different from conventional methods. <P>SOLUTION: A pneumatic tire 10 with a tread pattern includes at least three or more circumferential grooves extending in a tire circumferential direction, a plurality of width direction grooves extending in a tire width direction, and a plurality of block land parts sectioned by the circumferential grooves and the width direction grooves. This tire is assembled with an official rim. In the condition of a normal inner pressure and a normal load, if a ground contact area of a ground contact face of the tire is assumed to be R (mm<SP>2</SP>) when the tire contacts a horizontal surface, the modulus of 100% expansion elasticity of a tread rubber used for this tire is assumed to be E (kgf/mm<SP>2</SP>) at 20°C and the normal load is assumed to be W (kgf), the value E*R/W satisfies 7≥E*R/W ≥3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention provides at least three or more circumferential grooves extending in the tire circumferential direction, a plurality of width grooves extending in the tire width direction, and a plurality of blocks defined by the circumferential grooves and the width grooves. The present invention relates to a pneumatic tire with a tread pattern provided with a land portion.

Today, tire manufacturers are strongly demanded to develop tires that contribute to low fuel consumption in response to demands for low fuel consumption of vehicles. Specifically, it is desired to develop a tire having a lower rolling resistance than the conventional one.
In order to reduce the rolling resistance of a tire, generally, the viscoelastic characteristics, particularly tan δ, of a tread rubber that greatly contributes to the rolling resistance is reduced. However, a rubber member that reduces tan δ exhibits a tradeoff in performance that reduces the steering limit performance.

  On the other hand, Patent Document 1 below shows a desirable direction of the tire structure in order to reduce rolling resistance. The desirable direction of the tire structure for reducing rolling resistance in Patent Document 1 below is a portion where the tire contacts the ground by increasing the tension acting on the belt layer and decreasing the tension acting on the side carcass layer. It is described that the circularity of the belt is not greatly deviated from the circularity of the perfect circle before the ground contact. Thereby, the shear strain deformation between the two crossing layers in the belt layer is reduced, and the rolling resistance can be reduced by reducing the energy loss based on the viscoelastic properties of the rubber between the crossing layers.

JP 2002-79812 A

  However, as described in Patent Document 1, even if a tire is manufactured so that the circularity of the belt does not greatly deviate from the circularity of a perfect circle before grounding, the rolling resistance may not necessarily be reduced. .

  SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide a pneumatic tire with a tread pattern that can reduce rolling resistance by a method different from the conventional method.

The present invention is divided into at least three or more circumferential grooves extending in the tire circumferential direction, a plurality of width grooves extending in the tire width direction, the circumferential grooves and the width grooves. A pneumatic tire with a tread pattern having a land portion of a block of rim, assembled on a regular rim, and grounded on a horizontal surface under the conditions of normal internal pressure and normal load, the ground contact area of the pneumatic tire Where R (mm ² ), the tread rubber used in the pneumatic tire at 100 ° C. at 100 ° C. is E (kgf / mm ² ), and the normal load is W (kgf). Provided is a pneumatic tire with a tread pattern, wherein / W is 3 or more and 7 or less.

At that time, the ratio G = (A + B) / R of the sum A + B of the groove area A of the circumferential groove and the groove area B of the width groove with respect to the ground contact area R is 0.25 or less, The ratio S = B / (A + B) of the groove area B of the width direction groove to the sum A + B of the groove area A of the direction groove and the groove area B of the width direction groove is larger than 0.25 and smaller than 0.45 The circumferential groove is divided into a tread center region located on the tire center side and a tread shoulder region located on the opposite side of the tire center with a center line of the circumferential groove located on the outermost side in the tire width direction as a boundary. Then, the ratio G _s = C / Y of the sum C of the groove area of the circumferential groove and the groove area of the width direction groove in the tread shoulder region to the contact area Y in the tread shoulder region of the ground contact surface is 0.2. Smaller A, it is preferable that the ratio G _s is less than the ratio G.

The tread rubber preferably has a tan δ at 100 ° C. of 0.01 or more and 0.10 or less.
The circumferential groove is preferably at least five grooves.
Furthermore, it is preferable that at least one groove wall angle of the circumferential groove is 8 degrees or more.
Of the circumferential grooves, it is also preferable that the groove wall angle of the circumferential groove located on the outermost side in the tire width direction varies along the tire circumferential direction.
It is preferable that the groove depth of the width direction groove is 30% or more of the depth of the circumferential groove, and the width of the width direction groove is 20% or more of the groove width of the circumferential groove.

  Furthermore, a belt reinforcement layer is provided on the upper layer of the belt layer of the tire, and the distance between the groove bottom of the circumferential groove closest to the tread center position and the upper edge of the belt reinforcement layer is the circumferential groove. It is preferable that it is 3 mm or more and 5.5 mm or less.

  The pneumatic tire of the present invention can reduce rolling resistance by setting the value E · R / W defined above to be 3 or more and 7 or less. This method is different from the desired direction for reducing rolling resistance in Patent Document 1.

  Hereinafter, a pneumatic tire with a tread pattern of the present invention will be described in detail based on an embodiment shown in the accompanying drawings. The pneumatic tire of the present invention can be used particularly effectively for truck and bus tires described in JATMA.

  FIG. 1 is a cross-sectional view showing a cross-sectional shape of a pneumatic tire (hereinafter referred to as a tire) 10 which is an embodiment of a pneumatic tire with a tread pattern of the present invention. The tire 10 includes a tread portion A, a sidewall portion B, and a bead portion C as main components. In FIG. 1, CL represents a tire center.

  The tire 10 mainly includes a tread rubber 18, a side rubber 20, a bead filler rubber 22, a rim cushion rubber 24, and an inner liner rubber 26 in addition to the carcass layer 12, the bead core 14, and the belt layer 16. .

  The carcass layer 12 has a configuration in which reinforcing cords made of organic fibers are arranged in one direction at regular intervals, for example, in the tire width direction, and covered with a cord coating rubber. The carcass layer 12 is folded back from the tire inner side to the tire outer side by a pair of left and right bead cores 14 to be described later, and terminates in the region of the sidewall portion B.

  The belt layer 16 has a laminated structure including four layers of a first belt 16a, a second belt 16b, a third belt 16c, and a fourth belt 16d. Each belt is inclined at a predetermined angle with respect to the tire circumferential direction orthogonal to the tire width direction (direction orthogonal to the paper surface of FIG. 1), and the inclination directions between the belts are also different, forming an intersecting layer. .

For example, the first belt 16a has an inclination angle with respect to the tire circumferential direction of 40 to 80 degrees, the second belt 16b has an inclination angle of, for example, 10 to 40 degrees, and the third belt 16c has an inclination angle of, for example, 10 degrees. The fourth belt 16d has an inclination angle of, for example, 10 to 30 degrees. As for the direction of the inclination angle, the first belt 16a and the second belt 16b are inclined to the same side with respect to the tire circumferential direction, and the third belt 16c and the fourth belt 16d are the same as the first belt 16a and the second belt 16b. Inclined to different sides.
The belt width of the second belt 16b is the widest, and the third belt width has a shape that jumps in the direction of the tread surface at both ends. The fourth belt has the narrowest belt width.
The tire 10 may further be provided with a belt reinforcing layer in which organic fibers are arranged at regular intervals in the tire circumferential direction on the belt layer 16.

The bead core 14 is a ring-shaped member formed by continuously winding a bead wire made of a steel wire in an arc shape. The bead core 14 is a portion that functions so that the bead portion C of the tire is fixed to the rim of the wheel. The carcass layer 12 is folded around the bead core 14 from the tire inner side toward the tire outer side to fix the carcass layer 12. Thereby, tension is formed in the carcass layer 12 by the tire internal pressure.
The bead core 14 is provided with a bead filler rubber 22 between the carcass layer 12 and the folded carcass layer 12 to increase the rigidity of the bead portion C and define the shape of the sidewall portion B of the tire. The shape is arranged.

The side rubber 20 has a function of protecting the carcass layer 12 from the outside and ensuring the rigidity of the side portion together with the tension generated in the carcass layer 12.
The rim cushion rubber 24 is provided in a portion in contact with the wheel, and protects the bead portion C in contact with the wheel from being rubbed and damaged by the rim of the wheel. The inner liner rubber 26 is provided so as to cover the entire inner peripheral surface of the tire from one bead portion C to the other bead portion C, and functions so as not to leak air filled between the tire and the wheel.

The tread rubber 18 is provided in the upper layer of the belt layer 16 and comes into contact with the ground to smoothly roll the tire. Here, the material of the tread rubber 18 is set as follows.
That is, when the rim is assembled to a normal rim, and the ground contact area of the tire when it contacts the horizontal surface under the conditions of normal internal pressure and normal load is R (mm ² ), the tread rubber used for this pneumatic tire at 20 ° C. The material of the tread rubber is set so that the value E · R / W is 3 or more and 7 or less when the 100% stretch modulus is E (kgf / mm ² ) and the normal load is W (kgf). ing. An elastic modulus of 100% refers to a material that conforms to a predetermined elongation tensile stress measurement method defined in JIS K6251.

Here, the regular rim refers to an “applied rim” defined in JATMA, a “Design Rim” defined in TRA, or a “Measuring Rim” defined in ETRTO. The normal internal pressure means the “maximum air pressure” specified by JATMA, the maximum value of “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” specified by TRA, or “INFALATION PRESSURES” specified by ETRTO. . The normal load means “maximum load capacity” defined in JATMA at the normal internal pressure, TIRE LOAD LIMITS at the air pressure defined in TRA, or “LOAD CAPACITY” defined in ETRTO.
The contact area R refers to the total area of the area where the tire tread directly contacts the ground and the area of the groove portion on the contact surface.

Ｖ_iは、トレッドゴムの微小要素に分割したときの微小要素ｉの微小体積
π_iは、微小要素の歪みエネルギー
ｔａｎδは、トレッドゴム１８の正接損失 As described above, the tread rubber 18 is set such that the value E · R / W is 3 or more and 7 or less because the rolling resistance can be suitably reduced.
That is, in a rolling tire, the tread rubber is generally subjected to ground deformation from the ground with a substantially constant stress. On the other hand, the side rubber is deformed from the ground with a constant strain.
On the other hand, when a tread rubber having a large contribution in reducing rolling resistance receives an input from the ground with a constant stress, the rolling resistance is proportional to the energy dissipated by the tread rubber as shown in the following equation.

V _i is the micro volume of the micro element i divided into micro elements of the tread rubber π _i is the strain energy of the micro element tan δ is the tangent loss of the tread rubber 18

  When the above formula is expressed more simply, it is expressed by 1/2 · W · h / (E · R / W) · tan δ (h is the thickness of the tread rubber 18). That is, in order to reduce dissipated energy, in addition to reducing tan δ of the tread rubber 18, the value (E · R / W) in the above formula may be reduced. The present inventors pay attention to this point and have found that if the tread rubber 18 is selected so that the value E · R / W is 3 or more and 7 or less, the rolling resistance can be efficiently reduced. This point will be described in the following examples. Note that tan δ is preferably set to 0.01 or more and 0.10 or less.

Further, the tire 10 has a tread pattern as shown in FIG.
That is, the tire 10 is provided with circumferential grooves 40 to 46 extending in the circumferential direction and width direction grooves communicating between the circumferential grooves, and is further defined by the circumferential grooves 40 to 46 and the width direction grooves. A land portion of a plurality of blocks is formed.
Here, the groove depth of the width direction groove is 30% or more of the groove depth h (see FIG. 3) of the circumferential groove 40 to 46, and the groove width of the width direction groove is equal to that of the circumferential groove 40 to 46. It is 20% or more of the groove width w (see FIG. 3).
The ratio G = (A + B) / R of the sum A + B of the groove area A of the circumferential grooves 40 to 46 and the groove area B of the other width direction grooves to the ground contact area R is 0.25 or less. Moreover, the ratio S = B / (A + B) of the groove area B of the width direction groove to the sum A + B of the groove area A of the circumferential grooves 40 to 46 and the groove area B of the other width direction grooves is larger than 0.25. And smaller than 0.45.
Furthermore, when the circumferential grooves 40 to 46 are divided into a tread center region and a tread shoulder region with the center line of the circumferential grooves 44 and 46 located on the outermost side in the tire width direction as a boundary,
The ratio G _s = C / Y of the sum C of the groove area in the circumferential direction and the groove area in the width direction in the tread shoulder region to the contact area Y in the tread shoulder region of the contact surface is smaller than 0.2. The ratio G _s is smaller than the ratio G.

  Note that the groove area C of the tread shoulder region includes the groove area of the portion in the tread shoulder region with respect to the center line out of the groove areas of the circumferential grooves 44 and 46, and if included in the ground plane, the tread A widthwise groove in the shoulder region is also included.

By setting the value of the ratio G = (A + B) / R to 0.25 or less, the rigidity of the land portion such as a block that is in direct contact with the ground of the tread portion is increased, and the ground deformation is caused by the constant stress. The distortion of these land parts becomes small, and the reduction of rolling resistance is made higher.
By making the ratio S larger than 0.25 and smaller than 0.45, it is possible to achieve both traction performance on the snow of the tire and rolling resistance. When the ratio is 0.25 or less, the traction performance on snow decreases, and when the ratio is 0.45 or more, rolling resistance increases.

By making the ratio G _s = C / Y smaller than 0.2, uneven wear resistance is improved. In addition, the ratio G _s is set to be smaller than the ratio G, it is possible to reduce the distortion of the tread portion of the tread shoulder areas to reduce rolling resistance. In addition, the wear difference between both ends of the block in the tire circumferential direction is reduced, and uneven wear resistance is improved.

In the present invention, there may be at least five grooves. For example, as shown in FIG. 2 (b), there is exemplified one having five circumferential grooves and forming six block rows together with the widthwise grooves. Also in this case, the value E · R / W is 3 or more and 7 or less. By using five or more circumferential grooves, the ground pressure in each block row formed by sandwiching both sides between the circumferential grooves can be made uniform, and distortion acting on each block can be suppressed, and rolling resistance can be reduced. Can be reduced.
Further, the value of the ratio G = (A + B) / R is 0.25 or less, the ratio S = B / (A + B) is larger than 0.25 and smaller than 0.45, and the ratio G _s = C / Y is 0. less than 2, it is preferable that the ratio G _s is smaller than the ratio G.

  In the present invention, it is preferable that at least one groove wall angle of the circumferential groove is 8 degrees or more. When the groove wall angle is smaller than 8 degrees, when the strain acting on the block increases, the collapse of the block caused by the strain (the phenomenon that the block collapses so that the circumferential groove is collapsed) increases, and the rolling resistance increases. The groove wall angle is defined by θ shown in FIG.

  In the present invention, the groove wall angle of the circumferential groove located on the outermost side in the tire width direction among the circumferential grooves is configured to vary in a wavy or zigzag manner along the tire circumferential direction. Also good. By varying the groove wall angle along the tire circumferential direction, the rigidity of the block of the entire tread portion A can be increased, and the collapse of the block caused by distortion can be suppressed.

  Further, in the present invention, as shown in FIG. 4, when the belt reinforcing layer 17 is provided on the upper layer of the belt layer 16 of the tire, among the circumferential grooves 40 to 46, the circumferential grooves 40, closest to the tread center position The distance between the groove bottom of 42 and the upper edge of the belt reinforcing layer 17 is preferably 3 mm or greater and 5.5 mm or less. When the distance is larger than 5.5 mm, the thickness of the tread rubber under the groove bottoms of the circumferential grooves 40 and 42 is increased, the rigidity of the blocks on both sides of the circumferential grooves 40 and 42 is reduced, and the block collapses. Is likely to occur, increasing the rolling resistance. When it is smaller than 3 mm, the groove bottom easily causes damage to the groove bottom, and this damage is easily achieved up to the belt reinforcing layer 17.

In the tire of the present invention, the rolling resistance can be reduced by setting the value E · R / W in the range of 3 to 7. In order to achieve a value within this range, it is necessary to set the Young's modulus of the tread rubber higher than in the conventional case and to increase the ground contact area R.
In order to increase the ground contact area R, it is preferable to reduce the out-of-plane bending rigidity of the belt layer 16. That is, by reducing the out-of-plane bending rigidity of the belt layer 16, the belt circularity is greatly deviated from the circularity of the perfect circle before the ground contact, and the ground contact area is increased. In this respect, as described in the above-mentioned Patent Document 1, which is known as the prior art, the belt circularity is not greatly deviated from the circularity of a perfect circle before grounding, and the present invention is reversed. It has become a solution. This is because, in Patent Document 1, the purpose is to reduce the interlaminar shear strain generated between the belt crossing layers, and in the present invention, the purpose is to reduce the rolling resistance by reducing the strain energy of the tread rubber. It is.

Furthermore, in order to increase the ground contact area R, it is preferable to reduce the ratio G and ratio G _s in a pattern shape within a range that does not affect other performances. In addition to the reduction in resistance, there is also an effect that the wear resistance of the tread rubber is secondaryly improved.

[Example 1]
In order to examine the effect of the tire of the present invention, various tires were produced.
First, the tire pattern is a pattern with four circumferential grooves shown in FIG. The pattern shown in FIG. 5 satisfies the following (a) to (d).
(A) The value of the ratio G = (A + B) / R is 0.25 or less.
(B) The ratio S = B / (A + B) is greater than 0.25 and less than 0.45.
(C) The ratio G _s = C / Y is smaller than 0.2.
(D) The ratio G _s is smaller than the ratio G.
The tire was a truck and bus tire, and the tire size was 275 / 80R22.5. The manufactured tire was assembled on a regular rim of JATMA standard, and the rolling resistance was examined under conditions of a normal internal pressure (900 kPa) and a normal load (33.83 kN).

As described in Table 1 below, the contact area R was changed by changing the inclination angle of the belt layer. The circumferential grooves 50 and 52 of the pattern were provided so that the groove depth was 16 mm and the groove width was 8 mm, and the groove center position was 23 mm from the center CL. The circumferential grooves 54 and 56 of the pattern were provided so that the groove depth was 16 mm and the groove width was 8 mm, and the groove center position was 70 mm from the center CL. Each of the width direction grooves 58 has a groove depth of 11 mm and a groove width of 3 mm.
The tread rubber had a 100% elastic modulus E at 20 ° C. of 2.4 MPa (= 0.2447 kgf / mm ² ) and a tan δ at 100 ° C. of 0.06. The normal load W was 33.83 kN (= 3450 kgf).
The rolling resistance was set to 30.89 kN (= 3150 kgf) with a drum type rolling resistance tester. The value of the rolling resistance of the tire A was used as a reference (100), and the value of the rolling resistance of each tire was indexed. The index indicates that the higher the value, the smaller the rolling resistance value.

上記表１中のＥは２０℃における１００％伸張弾性率を表す。タイヤＦ,Ｇのトレッドゴムは、タイヤＡ〜Ｅのトレッドゴムと異なる。タイヤＦ,Ｇのトレッドゴムの１００℃におけるｔａｎδは、タイヤＡ〜Ｅに用いるトレッドゴムと同等の値０．０６を有する。第１ベルト及び第２ベルトのベルト傾斜角度の向きはいずれも同じ向きであり、第３ベルト及び第４ベルトのベルト傾斜角度のいずれも同じ向きであり、第１ベルト及び第２ベルトの向きと異なる。
タイヤＡ〜Ｄ，Ｆ，Ｇにおける図４に示すｔは、５．７ｍｍである。

E in Table 1 above represents a 100% stretch modulus at 20 ° C. The tread rubber of the tires F and G is different from the tread rubber of the tires A to E. The tan δ at 100 ° C. of the tread rubber of the tires F and G has a value 0.06 equivalent to that of the tread rubber used for the tires A to E. The first belt and the second belt have the same belt inclination angle, the third belt and the fourth belt have the same belt inclination angle, and the first belt and the second belt have the same direction. Different.
In the tires A to D, F, and G, t shown in FIG. 4 is 5.7 mm.

  The tires B and F corresponding to the tires of the present invention all have a high index of rolling resistance with respect to the tires A, C, D, and G that deviate from the range 3 to 7 of the value E · R / W in the present invention. It can be seen that the rolling resistance is small. Further, the tire E having a distance t of 5.2 mm between the groove bottoms of the circumferential grooves 50 and 52 and the upper edge of the belt reinforcing layer has a rolling resistance with respect to the tire A having a distance t of 5.7 mm. It can be seen that the index is extremely large and the rolling resistance is extremely small.

[Example 2]
In order to investigate the effect of the tire of the present invention, the effect of the pattern was examined.
First, as the tire pattern, a pattern having four and five circumferential grooves shown in FIGS. 2A and 2B was used. The patterns shown in FIGS. 2A and 2B satisfy the following (a) to (d).
(A) The value of the ratio G = (A + B) / R is 0.25 or less.
(B) The ratio S = B / (A + B) is greater than 0.25 and less than 0.45.
(C) The ratio G _s = C / Y is smaller than 0.2.
(D) The ratio G _s is smaller than the ratio G.
The tire size of the tire was 275 / 80R22.5. The produced tire was assembled on a regular rim of JATMA standard, and the rolling resistance and wear resistance performance were examined under the conditions of normal internal pressure and normal load.

  As described in Table 2 below, the contact area R was changed by changing the pattern and the inclination angle of the belt layer. The circumferential grooves 40 and 42 of the pattern shown in FIG. 2A are provided so that the groove depth is 16 mm and the groove width is 8 mm, and the groove center position is 23 mm from the center CL. The circumferential grooves 44 and 46 of the pattern were provided so that the groove depth was 16 mm and the groove width was 8 mm, and the groove center position was 70 mm from the center CL. Each of the width direction grooves 47 had a groove depth of 11 mm and a groove width of 3 mm.

Similarly, the circumferential grooves 41, 43, and 45 of the pattern shown in FIG. 2B have a groove depth of 16 mm and a groove width of 6 mm, and the center positions of the grooves from the center CL are 0 mm, 35 mm, and 35 mm, respectively. Provided. The circumferential grooves 48 and 49 of the pattern were provided so that the groove depth was 16 mm and the groove width was 8 mm, and the groove center position was 73 mm from the center CL. All of the grooves in the width direction had a groove depth of 11 mm and a groove width of 3 mm.
That is, the groove depth of the width direction groove is 30% or more of the depth of the circumferential groove, and the groove width of the width direction groove is 20% or more of the groove width of the circumferential groove.

Tread rubber is 100% elongation modulus E at 20 ° C. is 2.4 (MPa) (= 0.2447kgf / mm 2), tanδ was 0.06 at 100 ° C.. The normal load W was 33.83 KN (= 3450 kgf).
The rolling resistance was a drum type rolling resistance tester, and the value of rolling resistance of the tire H was set as a reference (100) with a load of 30.89 kN (= 3150 kgf), and the rolling resistance value of each tire was indexed. The index indicates that the higher the value, the smaller the rolling resistance value.

  In addition, as for durability performance, the wear amount of the tread after traveling on a 25-ton (6 × 2) truck at a traveling speed of 80 km / hour and traveling a distance of 50000 km was examined. Each tire was indexed with the wear amount of the tire G as a reference (100). The index indicates that the higher the numerical value, the smaller the amount of wear and the higher the wear resistance performance.

上記表２中のＥは２０℃における１００％伸張弾性率を表す。タイヤＬ，Ｍのトレッドゴムは、タイヤＨ〜Ｋのトレッドゴムと異なる。タイヤＬ，Ｍのトレッドゴムの１００℃におけるｔａｎδは、タイヤＨ〜Ｋに用いるトレッドゴムと同等の値０．０６を有する。第１ベルト及び第２ベルトのベルト傾斜角度の向きはいずれも同じ向きであり、第３ベルト及び第４ベルトのベルト傾斜角度のいずれも同じ向きであり、第１ベルト及び第２ベルトの向きと異なる。

E in Table 2 above represents a 100% stretch modulus at 20 ° C. The tread rubbers of the tires L and M are different from the tread rubbers of the tires H to K. The tan δ at 100 ° C. of the tread rubber of the tires L and M has a value 0.06 equivalent to that of the tread rubber used for the tires H to K. The first belt and the second belt have the same belt inclination angle, the third belt and the fourth belt have the same belt inclination angle, and the first belt and the second belt have the same direction. Different.

  In each of the patterns shown in FIGS. 2A and 2B, tires J and L having values E · R / W in the ranges 3 to 7 of the present invention have values E · R / W in the range 3 of the present invention. It can be seen that the rolling resistance index is large with respect to tires H, I, K, and M not present in ˜7, the rolling resistance is reduced, and the wear resistance is also improved.

  As mentioned above, although the pneumatic tire with a tread pattern of the present invention was explained in detail, the present invention is not limited to the above-mentioned embodiment, and various improvements and changes may be made without departing from the gist of the present invention. Of course.

It is sectional drawing which shows the cross-sectional shape of the pneumatic tire which is one Embodiment of the pneumatic tire with a tread pattern of this invention. (A) And (b) is an expanded view of the tread pattern used for the pneumatic tire shown in FIG. It is a figure explaining the cross-sectional shape of the circumferential groove | channel used for the pneumatic tire shown in FIG. When using a belt reinforcement layer for the pneumatic tire shown in FIG. 1, it is a figure explaining the relationship between this belt reinforcement layer and a circumferential groove | channel. It is an expanded view of the tread pattern used for the Example of the pneumatic tire with a tread pattern of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Pneumatic tire 12 Carcass layer 14 Bead core 16 Belt layer 16a 1st belt 16b 2nd belt 16c 3rd belt 16d 4th belt 18 Tread rubber 20 Side rubber 22 Bead filler rubber 24 Rim cushion rubber 26 Inner liners 40-46, 48, 49 , 50, 52, 54, 56 Circumferential groove 47, 58 Width direction groove

Claims (8)

A plurality of block land is defined by at least three circumferential grooves extending in the tire circumferential direction, a plurality of width grooves extending in the tire width direction, and the circumferential grooves and the width grooves. A pneumatic tire with a tread pattern comprising a portion,
When the rim is assembled to a regular rim and the ground contact area of the pneumatic tire is grounded on a horizontal surface under the conditions of regular internal pressure and regular load, the ground contact area of the pneumatic tire is R (mm ² ), and the tread rubber used for the pneumatic tire is 20 ° C. When the 100% stretching elastic modulus of E is kg (f / mm ² ) and the normal load is W (kgf),
A pneumatic tire with a tread pattern, wherein the value E · R / W is 3 or more and 7 or less. The ratio G = (A + B) / R of the sum A + B of the groove area A of the circumferential groove and the groove area B of the widthwise groove to the ground contact area R is 0.25 or less,
The ratio S = B / (A + B) of the groove area B of the widthwise groove to the sum A + B of the groove area A of the circumferential groove and the groove area B of the widthwise groove is greater than 0.25 and 0.45 Smaller,
When the circumferential groove is divided into a tread center region located on the tire center side and a tread shoulder region located on the opposite side of the tire center with the center line of the circumferential groove located on the outermost side in the tire width direction as a boundary. ,
A ratio G _s = C / Y of the sum C of the groove area of the circumferential groove and the groove area of the width direction groove in the tread shoulder region to the contact area Y in the tread shoulder region of the ground contact surface is smaller than 0.2. ,
Further, the ratio G _s tread patterned pneumatic tire according to the ratio G is smaller than claim 1.   3. The pneumatic tire with a tread pattern according to claim 1, wherein tan δ at 100 ° C. of the tread rubber is 0.01 or more and 0.10 or less.   The pneumatic tire with a tread pattern according to claim 1, wherein the circumferential grooves are at least five grooves.   The pneumatic tire with a tread pattern according to any one of claims 1 to 4, wherein at least one groove wall angle of the circumferential groove is 8 degrees or more.   The tread pattern-attached air according to any one of claims 1 to 5, wherein a groove wall angle of a circumferential groove located on the outermost side in the tire width direction among the circumferential grooves varies along the tire circumferential direction. Enter tire.   The groove depth of the width direction groove is 30% or more of the depth of the circumferential groove, and the groove width of the width direction groove is 20% or more of the groove width of the circumferential groove. The pneumatic tire with a tread pattern according to any one of 6. Furthermore, a belt reinforcement layer is provided on the upper layer of the belt layer of the tire,
The distance between the groove bottom of the circumferential groove closest to the tread center position and the upper edge of the belt reinforcing layer among the circumferential grooves is 3 mm or more and 5.5 mm or less. A pneumatic tire with a tread pattern according to claim 1.

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