JP5917889B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire, and more particularly, to a heavy-duty pneumatic tire suitable for use in trucks and buses, having a radial structure, employing a circumferential belt for maintaining the tire shape.

  Conventionally, a heavy duty radial tire that employs a circumferential belt mounted in layers in the tire circumferential direction on the outer side in the tire radial direction of the carcass, for example, an ultra flat truck / bus radial tire (Truck / Bus Radial Tire) : TBR) and the like are known.

  In recent years, in large trucks and buses, there are many examples of adopting a single tire mounting structure to reduce the fuel consumption and weight of the vehicle, and to reduce the flatness of the tire corresponding to this single mounting structure And the tread base is becoming wider. In general, a pneumatic tire with a low flatness ratio includes a belt composed of a pair of crossing belts and a circumferential belt for reinforcing the tire in the circumferential direction, so that the tire shape is maintained at a high internal pressure load, and The anti-centrifugal force and the heat resistance during running of the vehicle are improved, thereby improving the tire durability.

Thus, it is indispensable from the viewpoint of maintaining the shape of the tire that the circumferential belt is used in accordance with the reduction in the flatness of the tire, and the load load on the tire tends to increase year by year. There is also a need for improved tire durability.
The circumferential belt can be highly effective in maintaining shape retention, that is, uniform growth in the tire radial direction of the tread, but since it hardly exhibits shear rigidity, the wear resistance of the tire is reduced. In order to satisfy the demand for improved performance, an angled belt in which the belt cord is inclined with respect to the tire equator is required. In order to determine the wear resistance of the tire, the angled belt needs to have a belt width with a ratio to the tire width of a certain value or more, and the upper and lower belt cords cross each other. Need to be.

In addition to having the function of efficiently maintaining the shape of the circumferential belt, the circumferential belt also has the function of making the ground pressure on the tread surface uniform when the tire is in contact with the load. When the width is narrow, the contact pressure on the tread surface is high in the circumferential belt arrangement region but extremely low on the outer side thereof, thereby causing uneven wear. Therefore, the belt in the circumferential direction requires a belt width that is a certain ratio or more with respect to the tread width, and the ratio (circumferential belt width / tire width) increases as the flattening of the tire proceeds.
As an example having such a circumferential belt and a crossing belt that reinforces the tire circumferential direction, for example, an “air” having a divided structure in which a tread is divided in the tire width direction and at least two kinds of rubber are arranged in the tire width direction. There is a “entered radial tire” (see Patent Document 1).

  By the way, in general, widening the belt width of each belt suppresses the occurrence of uneven wear and improves steering stability. However, when the belt width is widened in the dark clouds, the belt stretches when a load is applied to the tire. As a result, there is a risk that the cord may be cut at the end of the circumferential belt, so conventionally, the width of the crossing belt is narrowed or the width of the circumferential belt itself is narrowed, and the belt is distorted. By suppressing this, the occurrence of problems was prevented.

JP 2001-121919 A

  However, if the width of the crossing belt or the width of the circumferential belt itself is narrowed, there is a possibility that sufficient shearing rigidity may not be ensured with the crossing belt having a narrow belt width. The circumferential wear belt with a narrow belt width may lead to deterioration of uneven wear resistance, which may lead to insufficient rigidity of the entire belt. Will be worsened.

  An object of the present invention is to provide a pneumatic tire capable of ensuring belt durability and obtaining sufficient shear rigidity, without deteriorating uneven wear resistance, and improving steering stability. is there.

In order to achieve the above object, a pneumatic tire according to the present invention is a pneumatic tire having at least a pair of circumferential grooves with the tire equator sandwiched between the treads and is located on the outermost side of the tread defined by the circumferential grooves. The tread rubber constituting the shoulder land portion is divided into the outer side in the tire width direction and the inner side in the tire width direction, and the elastic modulus of the tread rubber on the outer side in the tire width direction is made larger than the elastic modulus of the tread rubber on the inner side in the tire width direction. The tread rubber constituting the inner land portion adjacent to the inner side in the tire width direction through the circumferential groove on the shoulder land portion is divided into a tire width direction outer side and a tire width direction inner side, and the tire width of the inner land portion The elastic modulus of the tread rubber on the outer side in the direction is made larger than the elastic modulus of the tread rubber on the outer side in the tire width direction of the shoulder land portion .
Further, in the pneumatic tire according to another aspect of the present invention, at least the tread is located on the outer side in the tire radial direction of the multiple crossing belt layers, and the crossing belt layer is located on the outer side in the tire radial direction of the carcass. located in the tire radial direction outer side of the layer of circumferential belt layer, the shoulder land portion, that you are characterized that are located in the outer side in the tire radial direction of the circumferential belt layer and the crossing belt layer.

Also, the pneumatic tire according to another aspect of the invention, the tread rubber in the tire width direction outer side shoulder land portion, the shoulder land portion 50% or less of the total volume is 5% or more, the inner land The tread rubber on the outer side in the tire width direction of the portion is 50% or less and 5% or more of the total inner land portion volume.

  In the pneumatic tire according to another aspect of the present invention, the tread rubber constituting the shoulder land portion has a modulus at 100% elongation at a temperature of 25 ° C. in a range of 1 MPa to 8 MPa. It is a feature.

According to the pneumatic tire according to the present invention, in the pneumatic tire having at least a pair of circumferential grooves with the tire equator sandwiched between the treads, the shoulder land portion located on the outermost side of the tread defined by the circumferential grooves is configured. the tread rubber is divided into the inner side in the tire width direction outer side and the tire width direction, the elastic modulus of the tread rubber of the tire width direction outside, and greater than the elastic modulus of the tread rubber of the tire width direction inner side, the shoulder land portion The tread rubber constituting the inner land portion adjacent to the inner side in the tire width direction through the circumferential groove is divided into the outer side in the tire width direction and the inner side in the tire width direction, and the tread rubber on the outer side in the tire width direction of the inner land portion the elastic modulus, the since the greater than the elastic modulus in the tire width direction outer side of the tread rubber of the shoulder land portion, sufficient shear to ensure the belt durability Tsuyoshi The obtained, without deteriorating the uneven wear resistance, also, it is possible to improve the steering stability, also can increase the lateral force on the shoulder land portion when applying the steering angle, further Ru can improve the steering stability.

Further, according to the pneumatic tire according to another aspect of the present invention, the tread is positioned on the outer side in the tire radial direction of the plurality of crossing belt layers, and the crossing belt layer is positioned at least on the outer side in the tire radial direction of the carcass. is positioned in the tire radial direction outer side of the layer of circumferential belt layer, the shoulder land portion, Ru can be applied to a pneumatic tire having a structure in which is positioned the outer side in the tire radial direction of the circumferential belt layer and the crossing belt layers .

Also, according to the pneumatic tire according to another aspect of the invention, the tread rubber in the tire width direction outer side of the shoulder land portion, the shoulder land portion 50% or less of the total volume is 5% or more, the The tread rubber on the outer side in the tire width direction of the inner land portion is 50% or less and 5% or more of the entire inner land portion, and if it exceeds 50%, the inner region in the tire width direction becomes smaller and the effect is reduced. If it exceeds 5%, it can be avoided that the inner region in the tire width direction becomes large and the effect becomes insufficient.

  Further, according to the pneumatic tire according to another aspect of the present invention, the tread rubber constituting the shoulder land portion has a modulus at 100% elongation at a temperature of 25 ° C. in a range of 1 MPa to 8 MPa. Therefore, it is possible to prevent the rubber from being destroyed due to the rigidity difference between the adjacent rubbers.

1 is a cross-sectional view along a tire width direction schematically showing a part of a configuration of a pneumatic tire according to an embodiment of the present invention. The generation | occurrence | production situation of the tire lateral force by a lateral input is shown, (a) is schematic explanatory drawing, (b) is the detailed explanatory drawing seen for every block.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view along the tire width direction schematically showing a part of the configuration of a pneumatic tire according to an embodiment of the present invention. As shown in FIG. 1, the pneumatic tire 10 is an ultra-flat radial heavy-duty tire such as a truck / bus radial tire (TBR), and the tire diameter of the carcass 11 and the carcass 11 constituting the tire skeleton. The belt 12 is located on the outer side in the tire direction, the tread 13 is located on the outer side in the tire radial direction of the belt 12, and the sidewall 14 is located on the outer side in the tire width direction of the carcass 11.
The carcass 11 is bridged in a toroidal shape between a pair of left and right bead cores (not shown) having an annular structure.

  The belt 12 has a laminated structure in which at least one circumferential belt layer 15 and a plurality of intersecting belt layers 16 are arranged on the outer side in the tire radial direction of the carcass 11 in the order of description. Here, the case where the circumferential belt layer 15 is one layer and the cross belt layer 16 is two layers (16a, 16b) will be described as an example. These belt layers are formed by, for example, a strip formed by rubber coating a plurality of belt cords made of steel fiber material or organic fiber material. In particular, the circumferential belt is formed by spirally winding a narrow strip of rubber covered with several cords in the circumferential direction.

  The circumferential belt layer 15 is disposed so that the belt cord arrangement direction is substantially parallel to the tire circumferential direction, that is, with an inclination angle of, for example, 1 ° to 2 ° with respect to the tire equator. It is desirable to form the cord with a straight cord such as a WAVY cord or a high elongation cord brazed in a wavy shape. The growth rate in the tire radial direction at the normal internal pressure at the belt end of the circumferential belt layer 15 is desirably 0.3% or less.

The crossing belt layer 16 includes a slant belt layer 16a having the widest belt width in the tire width direction and a belt width of the cross belt that is laminated on the outer side in the tire radial direction of the slant belt layer 16a. The layer 16 has the two-layer structure of the inclined belt layer 16b that is the second largest. The belt width (Wa) of the inclined belt layer 16a is not narrower than the belt width (L) of the circumferential belt layer 15, and the belt width (Wb) of the inclined belt layer 16b is not wider than the belt width of the circumferential belt layer 15. (See FIG. 1). That is, each belt width of the circumferential belt layer 15 and the inclined belt layers 16a and 16b is:
Inclined belt layer 16b ≦ circumferential belt layer 15 ≦ inclined belt layer 16a
Are in a relationship.

The crossing belt layer 16 has an inclined belt layer 16a having the widest belt width of 80% or more with respect to the maximum distance in the tire width direction (hereinafter referred to as the maximum carcass width) of the carcass in the cross section in the tire width direction in a ground contact state with a normal internal pressure. The belt width is 95% or less, the belt shape is flat, and the inclined belt layer 16a and the inclined belt layer 16b have a belt width difference d of 10 to 50 mm on one side in the belt width direction (see FIG. 1). )have.
The cross belt layers 16 are arranged such that the belt cord arrangement direction is inclined with respect to the tire circumferential direction (tire equator) at a predetermined angle, and each of the plurality of cross belt layers 16 has the belt cord arrangement direction in the tire circumferential direction. The layers are laminated so as to incline in the upper and lower layers by inclining in directions different from each other (upward or leftward).

  The tread 13 has circumferential grooves (main grooves) 17 extending along the tire circumferential direction, at least one on each side in the tire width direction across the tire equator. Here, as an example, a case will be described in which two circumferential grooves are provided on both sides in the tire width direction across the tire equator.

  As shown in FIG. 1, of the two circumferential grooves 17a and 17b, the outermost circumferential groove 17a on the outermost side in the tire width direction is the belt end portion of the inclined belt layer 16b whose belt width is narrower than the inclined belt layer 16a. The crossing belt layer 16 is positioned on the outer side in the tire radial direction so as to overlap the inclined belt layer 16b on the inner side in the tire width direction. The outermost circumferential groove 17a is preferably disposed closer to the tread grounding end than the position where the center of the opening width is 45% of the tread half-width from the tread grounding end. A tread shoulder land portion (shoulder land portion) 13a is defined in a rib shape on the outermost side.

Accordingly, the circumferential belt layer 15 and the inclined belt layers 16 a and 16 b reach the inner side in the tire radial direction of the tread shoulder land portion 13 a so as to be applied to the tread shoulder land portion 13 a of the tread 13.
The tread shoulder land portion 13a is divided into two in the tire width direction and is formed of two types of tread rubber having different elastic moduli on the inner side and the outer side in the tire width direction. The outer side in the tire width direction is larger. Further, the tread rubber (inner land portion) 13b adjacent to the inner side in the tire width direction across the outermost circumferential groove 17a of the tread shoulder land portion 13a also has different elastic moduli on the inner side and the outer side in the tire width direction. The elastic modulus of the tread rubber on the outer side in the tire width direction of the tread land portion 13b is made larger than the elastic modulus of the tread rubber on the inner side in the tire width direction of the tread shoulder land portion 13a.

That is, the elastic modulus of the tread rubber 18a in the outer region in the tire width direction of the tread land portion 13b adjacent to the inner side in the tire width direction across the outermost circumferential groove 17a of the tread shoulder land portion 13a is A, and the tire of the tread land portion 13a. When the elastic modulus of the tread rubber 18b in the inner region in the width direction is B and the elastic modulus of the tread rubber 18c in the outer region in the tire width direction of the tread shoulder land portion 13a is C (see FIG. 1),
C> B, A> B
And
The boundary between the tread rubber 18a (elastic modulus A) and the tread rubber 18b (elastic modulus B) is the center of the groove bottom of the outermost circumferential groove 17a.

The relationship between the elastic moduli A, B, and C of these tread rubbers 18a, 18b, and 18c differs in the effect obtained by the relationship between the elastic modulus A and the elastic modulus C.
When the relationship between the elastic moduli A, B, and C is C>A> B, the lateral input becomes the largest at the tread end (tread shoulder), so the lateral force is increased by increasing the elastic modulus of the rubber at the tread end. It can be increased to improve steering stability.
When the relationship between the elastic moduli A, B, and C is A>C> B, the lateral force due to the lateral input at the tread end can be reduced to suppress the occurrence of uneven shoulder wear.

The outer region in the tire width direction of the tread shoulder land portion 13a and the outer region in the tire width direction of the tread land portion 13b are the entire volume of each tread shoulder land portion (block), that is, the cap rubber portion of the tread shoulder land portion 13a. 50% or less and 5% or more of the entire tire circumference. Thus, if it exceeds 50%, the inner region in the tire width direction becomes smaller and the effect is reduced, and if it exceeds 5%, the inner region in the tire width direction becomes larger and the effect becomes insufficient. it can.
Further, the tread rubbers 18a, 18b, and 18c are set so that the modulus (Mod.) At 100% elongation at a temperature of 25 ° C. is in the range of 1 MPa to 8 MPa. Thereby, it can prevent that the destruction of the rubber | gum by the rigidity level | step difference of adjacent rubber | gum generate | occur | produces.

  As described above, in the belt configuration of the pneumatic tire 10 according to the present invention, in order to improve the steering stability and suppress the occurrence of uneven wear, the wider belt width of the plurality of crossing belt layers 16 is set. The width of the carcass line is in the range of 80% to 95% and the belt width difference is 10 to 50 mm on one side in the belt width direction. The belt width of the layer 15 is also increased.

  However, if the belt width is increased as it is, the cord cut of the circumferential belt layer 15 occurs. Since the input for generating the cord break is due to the stretching of the belt of the circumferential belt layer 15 due to the stretching of the belt of the crossing belt layer 16, in order to suppress the stretching, the circumferential belt layer 15 Thus, it is effective to reduce the initial elongation generated when filling the tire with internal pressure. Therefore, if the growth in the tire radial direction at the normal inner pressure at the belt end portion of the circumferential belt layer 15 is 0.3% or less, the distortion of the belt end itself can be reduced.

The relationship between the belt widths of the circumferential belt layer 15 and the inclined belt layers 16a and 16b is as follows.
Inclined belt layer 16b ≦ circumferential belt layer 15 ≦ inclined belt layer 16a
This is because if the belt width of the circumferential belt layer 15 exceeds the belt width of the inclined belt layer 16a having the widest belt width, the failure core moves to the crossing belt layer 16 side and durability is deteriorated. If the belt width of the circumferential belt layer 15 is narrower than the belt width of the inclined belt layer 16b having the second largest belt width, the input from the cross belt layer 16 to the circumferential belt layer 15 increases, and the circumferential belt This is because the belt cord breakage of the layer 15 and the interlayer separation between the circumferential belt layer 15 and the crossing belt layer 16 occur.

At the same time, in order to ease the input from the circumferential belt layer 15, it is preferable to secure a belt end thickness (gauge: Ga.) Of 3 mm to 8 mm, particularly in the circumferential belt layer 15 where the input is concentrated. In order to secure the belt end thickness, the circumferential belt layer 15 is disposed along the carcass 11, and the crossing belt layer 16 is disposed substantially parallel to the tire width direction.
By having the configuration described above, the belt durability can be ensured and sufficient shear rigidity can be obtained. Therefore, it is not necessary to supplement the elastic modulus by arranging a rubber member around the belt 12.
In addition, by having the above-described configuration, sufficient belt rigidity can be obtained, and it is possible to achieve both improvement in steering stability and suppression of occurrence of uneven wear. In addition, in order to improve steering stability, the tread It has been found that the elastic modulus of the rubber is preferably in the range of 1 MPa to 8 MPa when the modulus at 100% elongation (Mod.) Is 25 ° C.

  FIGS. 2A and 2B show the state of occurrence of tire lateral force due to lateral input. FIG. 2A is a schematic explanatory view, and FIG. As shown in FIG. 2, when a steering angle is given to the wheels, the tire lateral force is generated by shear deformation of the tread rubber forming the tread 13 by lateral input to the tire (see (a)). Looking at the generation of tire lateral force in more detail for each block, it can be seen that deformation (see (b)) in which shear deformation due to lateral force and shear deformation due to crushing are combined has occurred. As a result, deformation in a direction that cancels the tire lateral force occurs in the tire width direction outer portion a (see (b)) of the circumferential groove (main groove) 17.

Since this deformation is unavoidable in a tire using rubber, the rubber elastic modulus of the outer region in the tire width direction of the circumferential groove 17 is not generated even if the deformation occurs. Is desirable to improve steering stability.
On the other hand, the tire width direction inner portion b (see (b)) across the circumferential groove 17 opposite to the tire width direction outer portion a of the circumferential groove 17 is deformed to promote tire lateral force. By increasing the rubber elastic modulus in the inner region in the tire width direction across the circumferential groove 17, it is possible to generate a force that further promotes the tire lateral force.

  Similarly, since the tire width direction outermost portion c (see (b)) is also deformed to promote the tire lateral force, the tire lateral force is further increased by increasing the rubber elastic modulus in the tire width direction outermost region. Power to promote is generated. However, increasing the rubber elastic modulus in the outermost region in the tire width direction also increases the reaction force that occurs when the tire tread 13 gets over the saddle on the road, so it is necessary to use it as necessary. .

Two types of pneumatic tires 10 according to the present invention (Examples 1 and 2) were prototyped, and two types of conventional examples (conventional examples 1 and 2) were obtained with respect to the number of broken belt cords, feeling, and uneven wear amount (uneven wear vol.). A comparative test with 2) and one type of comparative example (Comparative Example 1) was performed.
Hereinafter, specifications of Examples 1 and 2, Conventional Examples 1 and 2, and Comparative Example 1 will be described with reference to Table 1. The pneumatic tires of Examples 1 and 2, Conventional Examples 1 and 2, and Comparative Example 1 are all ultra-flat radial tires for heavy loads having a tire size of 495 / 45R225.
Belt width of the inclined belt layer 16a having the widest belt width:
Example 1 is 440 mm, Example 2 is 440 mm, Conventional Example 1 is 420 mm, Conventional Example 2 is 430 mm, and Comparative Example 1 is 440 mm.

Belt width of the inclined belt layer 16b having the second largest belt width:
Examples 1 and 2 and Comparative Example 1 are all 400 mm, Conventional Example 1 is 220 mm, and Conventional Example 2 is 390 mm.
Belt width of circumferential belt layer 15:
Example 1 is 420 mm, Example 2 is 430 mm, Conventional Example 1 is 370 mm, Conventional Example 2 is 350 mm, and Comparative Example 1 is 420 mm.
Maximum width of carcass line:
Each of Examples 1 and 2, Conventional Examples 1 and 2, and Comparative Example 1 is 494 mm.

Modulus A (rubber mod. A) at 100% elongation of the tread rubber 18a:
Example 1 is 3.2 Mpa, Example 2 is 3.4 Mpa, Conventional Examples 1 and 2 and Comparative Example 1 are all 2.9 Mpa.
Modulus B (rubber mod. B) at 100% elongation of the tread rubber 18b:
Examples 1 and 2 are both 2.2 Mpa, and Conventional Examples 1 and 2 and Comparative Example 1 are both 2.9 Mpa.
Modulus C (rubber mod. C) at 100% elongation of tread rubber 18c:
Example 1 is 2.9 Mpa, Example 2 is 3.2 Mpa, Conventional Examples 1 and 2 and Comparative Example 1 are all 2.9 Mpa.

The tire of the above-mentioned size (test tire) was assembled in an applicable rim having a rim size of 17.00 inches and evaluated for durability and handling stability at a regular internal pressure of 900 kPa.
Durability: The above-mentioned tire was run at 100,000 km in a drum-type running test machine at a specified load of 8500 kg and a speed of 80 km / h, and the number of belt cords in the circumferential belt layer 15 after running was examined.
Steering stability: The tire was mounted on the drive shaft of the tractor head, and a feeling evaluation was performed when the vehicle was slalomed with a trailer loaded with a constant load.
For reference, the uneven wear resistance (uneven wear vol.) At the end of the shoulder when the tire is mounted on the drive shaft of the tractor head and the empty trailer is pulled to travel 50,000 km Improved.

  Here, the applicable rim is an “applicable rim” defined by JATMA (The Japan Automobile Tire Manufacturers Association, Inc.), a TRA (THE RIRE AND RIM ASSOCIATION INC.), “Design Rim”, or ETRTO. “Measuring Rim” as defined in (THE European Tire and Rim Technical Organization). The normal internal pressure means “maximum air pressure” defined by JATMA, the maximum value of “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “INFLATION PRESSURES” defined by ETRTO. The specified load means “maximum load capacity” defined in JATMA, the maximum value of “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined in TRA, or “LOAD CAPACITY” defined in ETRTO.

In the pneumatic tires of Examples 1 and 2 according to the present invention, the following evaluation was made from the results of comparison with Conventional Examples 1 and 2 and Comparative Example 1 for durability (number of cords cut) and steering stability (feeling). Could be obtained (see Table 2).
Code cut number index (the smaller the number, the better):
The conventional example 1 is 100 (cont), the conventional example 2 is 131 and the comparative example 1 is 0, whereas both the examples 1 and 2 are 0 (that is, the belt cord is not cut).
Feeling index (higher is better):
The conventional example 1 is 100 (cont), the conventional example 2 is 110 and the comparative example 1 is 115, while the example 1 is 135 and the example 2 is 140.

Tread shoulder uneven wear index (smaller value is better):
The conventional example 1 is 100 (cont), the conventional example 2 is 93 and the comparative example 1 is 46, whereas the example 1 is 46 and the example 2 is 38.
As described above, the pneumatic tire 10 according to the present invention can ensure belt durability and obtain sufficient shear rigidity, without deteriorating uneven wear resistance, and improving steering stability. it can.

  According to the present invention, the durability of the belt is ensured to obtain sufficient shear rigidity, the uneven wear resistance is not deteriorated, and the steering stability can be improved, so that the tire shape is maintained. Therefore, it is suitable as a heavy duty pneumatic tire having a radial structure and suitable for use in trucks and buses.

DESCRIPTION OF SYMBOLS 10 Pneumatic tire 11 Carcass 12 Belt 13 Tread 13a Tread shoulder land part 13b Tread land part 14 Side wall 15 Circumferential belt layer 16 Crossing belt layer 16a, 16b Inclined belt layer 17 Circumferential groove 17a Outermost circumferential direction groove 18a, 18b, 18c Tread rubber A, B, C Elastic modulus a Tire width direction outer part b Tire width direction inner part c Tire width direction outermost part d Belt width difference

Claims (4)

In a pneumatic tire having at least a pair of circumferential grooves sandwiching the tire equator with the tread,
The tread rubber constituting the shoulder land portion located on the outermost side of the tread partitioned by the circumferential groove is divided into the tire width direction outer side and the tire width direction inner side, and the elastic modulus of the tread rubber on the tire width direction outer side is determined. Larger than the elastic modulus of the tread rubber inside the tire width direction ,
A tread rubber constituting an inner land portion adjacent to the shoulder land portion on the inner side in the tire width direction through the circumferential groove is divided into an outer side in the tire width direction and an inner side in the tire width direction, and the tire width direction of the inner land portion A pneumatic tire characterized in that the elastic modulus of the outer tread rubber is larger than the elastic modulus of the outer tread rubber of the shoulder land portion in the tire width direction . The tread is positioned on the outer side in the tire radial direction of a plurality of crossing belt layers, and the crossing belt layer is positioned on the outer side in the tire radial direction of at least one circumferential belt layer positioned on the outer side in the tire radial direction of the carcass.
2. The pneumatic tire according to claim 1, wherein the shoulder land portion is located on the outer side in the tire radial direction of the circumferential belt layer and the crossing belt layer. The tread rubber on the outer side in the tire width direction of the shoulder land portion is 50% or less and 5% or more of the total volume of the shoulder land portion, and the tread rubber on the outer side in the tire width direction of the inner land portion is the entire inner land portion. The pneumatic tire according to claim 1 or 2 , wherein the pneumatic tire is 50% or less and 5% or more of a product. Said tread rubber constituting the shoulder land portion is at 100% elongation at a temperature 25 ° C. modulus is pneumatic as claimed in any one of claims 1 to 3, characterized in that the range of 1MPa~8MPa tire.

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