JP2007230399A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire maintaining wearing-resistance property of a tread part and capable of preventing heat separation failure of the tread part by suppressing rising of a heat generation temperature of the tread part at tire load rolling by enhancing heat release effect. <P>SOLUTION: A circumferential thin groove 18, a width direction groove 16 and a width direction thin groove 20 having groove walls contacted with each other in a ground-contact surface are provided on the tread part 12, a second small groove 26B extending in a groove depth direction of the width direction thin groove 20 is provided on the groove wall of the width direction thin groove 20, and a first small groove 26A extending in the groove depth direction of the circumferential thin groove 18 is provided on the groove wall of the circumferential thin groove 18. Thereby, a heat release area of the tread part 12 is enhanced and heat release effect is enhanced by disturbing a flow of a fluid flowing in the respective thin grooves. Rising of the heat generation temperature of the tread part at the tire load rolling can be suppressed and the width direction thin groove 20 is closed in the ground-contact surface to maintain the wearing-resistance of the tread part 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire used for a construction vehicle or the like.

  Conventionally, a pneumatic tire having a so-called lug pattern in which a large number of lug grooves are arranged at predetermined intervals in the tire circumferential direction has been widely used as a tire for construction vehicles. This construction vehicle tire uses tread rubber with good wear resistance to improve its wear resistance, increase the tread volume, increase the tread gauge (deep groove), decrease the negative rate, It is common to use means such as increasing the land rigidity.

However, when the wear resistance is improved by using the above-mentioned means, there is a tendency that the exothermic property of the tread portion is deteriorated particularly at the time of tire rolling, and this exothermic deterioration is caused by the heat of the tread portion. This could cause a failure such as separation.
In particular, the land portion between each straight line along two tire circumferences formed by tying the end positions of the lug grooves substantially in the tire circumferential direction tends to increase the heat generation temperature because the heat radiation area is small. is there.

Therefore, a narrow groove having a groove width of 8 to 20 mm that can increase the heat radiation area in order to suppress the heat generation of the tread portion while minimizing the decrease in rigidity of the land portion and maintaining the wear resistance. In recent years, a technique for disposing the part has been developed. (For example, Patent Document 1)
JP 2004-262295 A

However, due to the recent increase in tire size, flattening, and heavy load, particularly with the increase in size of construction vehicles, there is a tendency for the exothermic deterioration of the tread portion to become prominent. The rise in exothermic temperature in the central area remains a problem.
In the market, while maintaining the wear resistance of the tread part, the rise in the heat generation temperature of the tread part during rolling of the tire load, particularly in the center area of the tread part, is suppressed by enhancing the heat dissipation effect, and the tread part Development of pneumatic tires for construction vehicles that can prevent heat separation failures is expected.

  In view of the above facts, the object of the present invention is to maintain the wear resistance of the tread portion, and suppress the increase in the heat generation temperature of the tread portion during rolling of the tire load by enhancing the heat dissipation effect. It aims at providing the pneumatic tire which can prevent the heat separation failure of a part.

  In order to achieve the above object, a pneumatic tire according to claim 1 of the present invention forms a tread portion that comes into contact with a road surface, is provided in a tread rubber having a thickness of 70 to 200 mm, and the tread portion, and has a groove width. A narrow groove of 8 to 20 mm, and a small groove provided on a groove wall of the narrow groove, extending in a direction intersecting with a longitudinal direction of the narrow groove, and disturbing a flow of fluid in the narrow groove. To do.

Next, the effect of the pneumatic tire according to claim 1 will be described.
By providing the small groove extending in the direction intersecting the longitudinal direction of the narrow groove on the groove wall of the narrow groove of the tread portion, the heat radiation area is increased and the heat radiation effect of the tread portion is improved. Further, the flow of fluid (air) flowing in the narrow groove is disturbed by the small groove, and the heat dissipation effect of the tread portion is improved.
Accordingly, an increase in the heat generation temperature of the tread portion during rolling of the tire load is suppressed by improving the heat dissipation effect, and a heat separation failure of the tread portion is prevented.

  In addition, since the groove width of the narrow grooves is set to 8 to 20 mm, the land portion defined by the narrow grooves is deformed by the load in the contact surface of the tread portion during rolling of the tire load, and these narrow grooves are substantially formed. It closes and the land surface continues to land, so that the rigidity of the land portion is improved and the wear resistance of the tread portion is maintained. In addition, since the groove width of these narrow grooves is restored outside the ground contact surface of the tread portion, the heat dissipation effect of the tread portion is not affected.

Furthermore, when the groove width of the narrow groove is less than 8 mm, the groove width is narrow, so that the air flow is small and the heat dissipation effect of the tread portion is reduced. When the groove width of the narrow groove exceeds 20 mm, the groove width is too wide, so that even if the land portion formed by the narrow groove is deformed in the ground contact surface of the tread portion at the time of tire load rolling, the land does not continue. Therefore, land part rigidity falls and the abrasion-resistant performance of a tread part will fall. Therefore, the groove width of the narrow groove preferably satisfies 8 to 20 mm.
From the above, the wear resistance of the tread portion is maintained, and an increase in the heat generation temperature of the tread portion at the time of tire load rolling is suppressed by improving the heat dissipation effect, thereby preventing a heat separation failure of the tread portion. .

  The pneumatic tire according to claim 2 of the present invention forms a tread portion that comes into contact with the road surface, and is provided with a plurality of tread rubbers having a thickness of 70 to 200 mm and both tread end sides of the tread portion. A plurality of widthwise grooves extending between the widthwise grooves on both sides in the tire width direction, a plurality of circumferentially narrow grooves extending in the tire circumferential direction, and a plurality of grooves provided between the plurality of circumferentially narrow grooves, A widthwise narrow groove that extends in the tire width direction and in which the groove walls are in contact with each other within the ground contact surface, and is provided in the groove wall of the widthwise narrow groove, and extends in a direction intersecting the longitudinal direction of the widthwise narrow groove; A small groove that disturbs the flow of fluid in the narrow groove in the width direction.

Next, the effect of the pneumatic tire of Claim 2 is demonstrated.
As described above, there is a problem that the heat generation temperature tends to rise in the tread portion, particularly in the central region of the tread portion. Here, the central region of the tread portion refers to a space between the widthwise grooves on both sides in the tire width direction, and a small groove extending in a direction intersecting the longitudinal direction of the widthwise narrow groove on the groove wall of the widthwise narrow groove in the central region. By providing, the heat radiation area is increased, and the heat radiation effect in the central region of the tread portion is improved. In addition, the small groove causes a disturbance in the flow of the fluid (air) flowing in the width direction narrow groove, and the heat dissipation effect in the central region of the tread portion is improved. Accordingly, an increase in the heat generation temperature of the tread portion, particularly in the central region, during tire load rolling is suppressed by improving the heat dissipation effect, and a heat separation failure of the tread portion is prevented.

In addition, since the groove width of the width direction narrow groove is a groove width such that the groove walls are in contact with each other in the ground contact surface, the width direction narrow groove is substantially closed at the time of tire load rolling, and the inside of the contact surface is Since the land is continuous, the rigidity of the land portion in the central region of the tread portion is improved and the wear resistance of the central region of the tread portion is maintained. In addition, since the groove width of the narrow groove in the width direction is restored outside the ground contact surface in the central area of the tread portion, the heat radiation effect in the central area of the tread portion is not affected.
From the above, the wear resistance of the central region of the tread portion is maintained, and an increase in the heat generation temperature of the tread portion, particularly in the central region during rolling of the tire load, is suppressed by improving the heat dissipation effect, so that the tread Heat separation failure of the part is prevented.

  The tread end mentioned here refers to a pneumatic tire mounted on a standard rim in the applicable size specified in the 2005 TRA YEAR BOOK issued by the TRA Association of Tires and Rim in the United States, and specified in the TRA YEAR BOOK. The maximum load (maximum load capacity) and the air pressure corresponding to the maximum load (maximum air pressure) at 100% of the applied size and ply rating are filled as internal pressure, and the outermost ground contact part in the tire width direction when the maximum load is applied Point to. In addition, when there is a standard in the place of use or the manufacturing place, it follows each standard.

  The pneumatic tire according to claim 3 of the present invention is the pneumatic tire according to claim 2, wherein the pneumatic tire extends in a direction intersecting with a longitudinal direction of the circumferential narrow groove on the groove wall of the circumferential narrow groove. A small groove that disturbs the flow of fluid in the circumferential narrow groove is provided.

Next, the effect of the pneumatic tire according to claim 3 will be described.
By providing the small groove in the circumferential narrow groove, the heat radiation area is increased and the heat radiation effect of the tread portion is further improved, and the flow of fluid (air) flowing in the narrow groove is disturbed by the small groove, and the tread The heat dissipation effect of the part is further improved.

  The pneumatic tire according to claim 4 of the present invention is the pneumatic tire according to claim 2 or 3, wherein each of the width direction narrow grooves and the circumferential direction narrow grooves satisfy 8 to 20 mm. It is characterized by.

Next, the effect of the pneumatic tire of Claim 5 is demonstrated.
When the width of each of the narrow grooves in the width direction and the narrow grooves in the circumferential direction is less than 8 mm, the groove width is narrow, so that the air flow is small and the heat dissipation effect in the central area of the tread portion is reduced. If the width of each of the narrow grooves in the width direction and the narrow grooves in the circumferential direction exceeds 20 mm, the width of the grooves is too wide. Even if the land portion formed by the narrow groove is deformed, the land portion is not continuous, so that the land portion rigidity of the land portion is lowered and the wear resistance performance in the central region of the tread portion is lowered. Therefore, it is preferable that the width of each of the narrow grooves in the width direction and the narrow grooves in the circumferential direction satisfy 8 to 20 mm.

  The pneumatic tire according to claim 5 of the present invention is the pneumatic tire according to any one of claims 1 to 4, wherein the groove depth of the small groove is the narrow groove in which the small groove is arranged or 20 to 100% of the groove depth of the width direction narrow groove or the circumferential direction narrow groove is satisfied.

Next, the effect of the pneumatic tire of Claim 5 is demonstrated.
When the groove depth of the small groove is less than 20% of the groove depth of the narrow groove, the width direction narrow groove, or the circumferential direction narrow groove in which the small groove is disposed, the fluid flowing in each narrow groove is caused to flow into each small groove. When the amount taken into the inside is small, and the groove depth of each small groove exceeds 100% of the groove depth of each narrow groove, there is a local portion where R is tight in each narrow groove. This will affect the crack resistance of the groove bottom. Therefore, it is preferable that the groove depth of each small groove satisfy | fills 20 to 100% of each groove depth.
Here, the groove depth of the small groove means a distance measured along the depth direction of the narrow groove, the width-direction narrow groove, or the circumferential narrow groove in which the small groove is disposed.

  In the pneumatic tire of the present invention, the wear resistance of the tread portion is maintained, and an increase in the heat generation temperature of the tread portion at the time of tire load rolling is suppressed by improving the heat dissipation effect, so that the heat separation failure of the tread portion is prevented. Is prevented.

[First Embodiment]
(Configuration) Next, a first embodiment of the pneumatic tire of the present invention will be described with reference to FIG. The pneumatic tire of the present embodiment is a construction vehicle pneumatic tire 10 (hereinafter, simply referred to as a tire 10) used for construction vehicles, and the tire size is 40.00R57. Further, since the internal structure of the tire 10 is the same as that of a general radial tire, description of the internal structure is omitted.

(Tread, groove, block)
A tread rubber 14 that forms a tread portion 12 that comes into contact with the road surface is provided on the outermost layer of the tire 10. The tread rubber 14 has a thickness of 70 to 200 mm.
As shown in FIG. 1A, in the tread portion 12, a plurality of widthwise grooves 16 extend from both tread ends 12E toward the equator plane CL (dashed line). Lines connecting the ends of the width direction grooves 16 on both sides in the tire width direction on the equator plane CL side in the tire circumferential direction are defined as boundary lines BL (two-dot chain lines), and between the boundary lines BL and the tread ends 12E. Is a tread side region 32 and a space between both boundary lines BL is a tread central region 30.

  Further, in the tread central region 30 of the tread portion 12, circumferential narrow grooves 18 extending in a zigzag manner in the tire circumferential direction are provided, one on each side of the equator plane CL. The two circumferential narrow grooves 18 are connected to the terminal ends of the respective widthwise grooves 16. Further, the tread central region 30 of the tread portion 12 is provided with a plurality of widthwise narrow grooves 20 that extend from one of the two circumferential narrow grooves 18 to the other and connect the circumferential narrow grooves 18. It has been.

  In addition, as shown in FIG. 1A, a plurality of land portions defined in a tread central region 30 by two circumferential narrow grooves 18 and a plurality of width narrow grooves 20 are divided into center blocks 22. The plurality of land portions defined in the tread side region 32 by the tread ends 12E, the two circumferential narrow grooves 18 and the plurality of width direction grooves 16 are referred to as shoulder blocks 24.

(Small groove)
As shown in FIG. 1B, a small groove 26 extending from the tread surface of the center block 22 in a direction intersecting with the longitudinal direction of the width direction narrow groove 20 is provided on the groove wall of the width direction narrow groove 20. The direction intersecting with the longitudinal direction of the width direction narrow groove 20 may be a direction perpendicular to the longitudinal direction or an inclined direction. In the present embodiment, the small groove 26 extends in parallel with the depth direction (arrow D direction) of the width direction narrow groove 20 that is perpendicular to the longitudinal direction of the width direction narrow groove 20.
The shape of the small groove 26A of the present embodiment is a regular triangle as shown in FIG. 1A when the tread surface of the tread portion 12 is viewed in plan, and the depth direction of the width direction narrow groove 20 remains the regular triangle. This is a so-called triangular prism shape. Moreover, one side of the equilateral triangle at this time is 8 mm.

It is preferable that the groove depth D1 of the small groove 26 satisfies 20 to 100% of the groove depth WD of the width direction narrow groove 20.
The groove width SW of the circumferential narrow groove 18 preferably satisfies 8 to 20 mm. Furthermore, it is preferable that the groove width WW of the width-direction narrow groove 20 also satisfies 8 to 20 mm.

  In the present embodiment, each of the width direction groove 16, the circumferential direction narrow groove 18 and the width direction narrow groove 20 has a uniform groove depth of 80 mm, and the groove depth D1 of the small groove 26 is also set to 80 mm. Yes. In other embodiments, the circumferential narrow groove 18, the widthwise groove 16, and the widthwise narrow groove 20 may have different groove widths and depths, and each groove may have a zigzag shape ( (Including a square wave shape, a sine wave shape, etc.) or a straight line shape. Furthermore, it is assumed that each groove depth, each groove width, and each groove shape may differ depending on the position where the small groove 26 is also disposed.

(Operation) Next, the operation of the first embodiment will be described.
Since the heat generation temperature of the tread portion 12, particularly in the tread central region 30, is likely to rise during tire load rolling, providing the small groove 26 in the groove wall of the widthwise narrow groove 20 in the tread central region 30 provides a heat dissipation area. It increases and the heat dissipation effect of the tread central region 30 improves. Further, as shown in FIG. 1C, the small groove 26 disturbs the flow of the air flowing in the width direction narrow groove 20, and the heat dissipation effect of the tread central region 30 is improved. Therefore, an increase in the heat generation temperature of the tread central region 30 at the time of tire load rolling is suppressed by improving the heat dissipation effect, and a heat separation failure of the tread portion 12 is prevented.

Further, since the groove width of the width direction narrow groove 20 is set to 8 to 20 mm, the center block 22 and the shoulder block 24 are deformed by the load in the contact surface of the tread portion 12 during rolling of the tire load, and the circumferential direction narrow groove. 18 and the width direction narrow groove 20 are substantially closed, and the inside of the ground contact surface is continuously landed, so that the block rigidity is improved and the wear resistance of the tread central region 30 is maintained.
In addition, since the groove width of these circumferential direction narrow grooves 18 and the width direction narrow grooves 20 is restored outside the ground surface of the tread part 12, the heat radiation effect of the tread part 12 is not affected.
From the above, the wear resistance of the tread central region 30 is maintained, and an increase in the heat generation temperature of the tread central region 30 at the time of tire load rolling is suppressed by improving the heat dissipation effect, so that the heat of the tread portion 12 is increased. Separation failure is prevented.

  When the groove depth D1 of the small groove 26 is less than 20% of the groove depth WD of the width direction narrow groove 20, the amount of fluid flowing in the width direction narrow groove 20 is small, and When the groove depth D1 of the small groove 26 exceeds 100% of the groove depth WD of the width-direction narrow groove 20, there is a portion where R is locally tight in the width-direction narrow groove 20, and the groove bottom resistance is increased. The cracking property will be affected. Therefore, it is preferable that the groove depth D1 of the small groove 26 satisfies 20 to 100% of the groove depth WD of the width direction narrow groove 20.

When the groove width WW of the width direction narrow groove 20 is less than 8 mm, since the groove width WW is narrow, the air flow is small, the heat dissipation effect of the tread central region 30 is reduced, and the groove width WW exceeds 20 mm. Since the groove width WW is too wide, even if the center block 22 is deformed in the ground contact surface of the tread portion 12 at the time of tire load rolling, the center block 22 does not continue to land, so that the block rigidity in the tire circumferential direction is increased. The wear resistance performance of the tread central region 30 is lowered. Therefore, it is preferable that the groove width WW of the width direction narrow groove 20 satisfies 8-20 mm.
When the groove width SW of the circumferential narrow groove 18 is less than 8 mm, since the groove width SW is narrow, the air flow is small, the heat dissipation effect of the tread central region 30 is reduced, and the groove width SW exceeds 20 mm. Since the groove width SW is too wide, even if the center block 22 and the shoulder block 24 are deformed in the ground contact surface of the tread portion 12 when rolling the tire load, the center block 22 and the shoulder block 24 are connected to the land. Therefore, the block rigidity in the tire width direction is lowered, and the wear resistance performance of the tread portion 12 is lowered. Therefore, it is preferable that the groove width SW of the circumferential narrow groove 18 satisfies 8 to 20 mm.

[Second Embodiment]
(Configuration) Next, a second embodiment of the pneumatic tire of the present invention will be described with reference to FIG. In addition, the pneumatic tire of this embodiment is also a pneumatic tire for construction vehicles like the pneumatic tire of the first embodiment, and the description thereof will be made only on the configuration different from that of the first embodiment. In the second embodiment, instead of the small groove 26 provided in the width direction narrow groove 20 of the first embodiment, the first small groove 26A is provided, and further, the second circumferential groove 18 is provided with the second small groove 26A. The point where the small groove 26B is provided is the difference from the first embodiment, and details of the first small groove 26A and the second small groove 26B will be described below. In addition, the same code | symbol is attached | subjected to the same structure as 1st Embodiment, and the description is abbreviate | omitted.

(Small groove)
As shown in FIG. 2A, a first small groove 26A extending from the tread surface of the center block 22 in a direction intersecting with the longitudinal direction of the width direction narrow groove 20 is provided on the groove wall of the width direction narrow groove 20. Yes. Further, a second small groove 26 </ b> B extending from the tread surface of the center block 22 and the shoulder block 24 in a direction intersecting with the longitudinal direction of the circumferential narrow groove 18 is provided on the groove wall of the circumferential narrow groove 18. In the present embodiment, the direction intersecting with the longitudinal direction of each narrow groove refers to the depth direction (arrow D direction) of each narrow groove.

  The shape of the first small groove 26A of the present embodiment is a triangular prism shape as shown in FIG. 2B, and the shape of the second small groove 26B is also a triangular prism shape. Specifically, when the first small groove 26A and the second small groove 26B are viewed in a tread plan view, the shape thereof is a quadrangle. At this time, the groove width of each of the first small groove 26A and the second small groove 26B is 4 mm, the groove length is 35 mm, and the groove depth is 20 mm.

  The groove depth D1 of the first small groove 26A preferably satisfies 20 to 100% of the groove depth WD of the width direction narrow groove 20. As shown in FIG. 2B, the groove depth D2 of the second small groove 26B preferably satisfies 20 to 100% of the groove depth SD of the circumferential narrow groove 18. The groove depth D1 is not shown.

(Operation) Next, the operation of the second embodiment will be described.
By providing the first small groove 26A in the width direction narrow groove 20 and the second small groove 26B in the circumferential direction narrow groove 18, the heat dissipation effect of the tread central region 30 is further improved, and the tread center during tire load rolling is improved. An increase in the heat generation temperature of the region 30 is further suppressed, and a heat separation failure of the tread portion 12 is prevented. Further, in the shape of the first small groove 26A and the second small groove 26B of the present embodiment, the air flow becomes a flow as shown in FIG.

  Further, when the groove depth D1 of the first small groove 26A is less than 20% of the groove depth WD of the width-direction narrow groove 20, the air flowing in the width-direction narrow groove 20 enters the first small groove 26A. When the amount to be taken in is small and the groove depth D1 of the first small groove 26A exceeds 100% of the groove depth WD of the width direction narrow groove 20, there is a portion where R is locally tight and the groove bottom This will affect the crack resistance. Therefore, it is preferable that the groove depth D1 of the first small groove 26A satisfies 20 to 100% of the groove depth WD of the width direction narrow groove 20.

  Further, when the groove depth D2 of the second small groove 26B is less than 20% of the groove depth SD of the circumferential narrow groove 18, the air flowing in the circumferential narrow groove 18 enters the second small groove 26B. When the amount to be taken in is small and the groove depth D2 of the second small groove 26B exceeds 100% of the groove depth SD of the circumferential narrow groove 18, there is a local portion where R is tight and the groove bottom This will affect the crack resistance. Therefore, the groove depth D2 of the second small groove 26B preferably satisfies 20 to 100% of the groove depth SD of the circumferential narrow groove 18.

(Other embodiments)
In the first and second embodiments, the pneumatic tire of the present invention is used as a pneumatic tire for construction vehicles, but may be used for other than construction vehicles.
In the first and second embodiments, the structure of the pneumatic tire of the present invention is a radial structure, but the structure of the tire may be a bias structure.

In the first and second embodiments, the present invention is used for a tire having a tire size of 40.00R57. However, the tire may be used for any tire as long as the flatness is 90% or less. This is because when the tire flatness ratio is 90% or less, the belt tension burden becomes larger than the general 95 series of OR tires (tires for construction vehicles), and the heat generation in the tread portion becomes larger. This is because it becomes more effective.
Further, if the present invention is used for a tire having a coefficient corresponding to the maximum speed of the tire load / load capability correspondence table defined in the TRA standard of 1.4 or more, the effect of the present invention can be further obtained. This is because if the coefficient corresponding to the maximum speed in the tire load load capacity correspondence table specified in TRA is 1.4 or more, the load on the tire air volume is increased and the heat generation in the tread portion is further increased. This is because the effect of the present invention becomes more effective.

(Test example)
In order to confirm the performance improvement effect of the pneumatic tire of the present invention, one type of pneumatic tire according to the first embodiment of the present invention, one type of pneumatic tire according to the second embodiment of the present invention, Prepare one kind of pneumatic tire of comparative example, assemble it into standard rim (TRA standard), fill 100% of air pressure (TRA standard) corresponding to maximum load (TRA standard) as internal pressure, then these The test tire was mounted on a construction vehicle and traveled at a constant speed of 10 km / h for 24 hours with the maximum load (TRA standard) applied, and then a narrow hole provided in the center block in advance. A thermocouple was inserted from (on the tire equator plane), and a temperature of 3.5 mm on the outermost layer was measured. Table 1 shows the measured values of the tire of Example 1 and the tire of Example 2 with the temperature of the tire of the comparative example as the reference temperature.
Note that the tire sizes of the test tires are all 40.00R57. Moreover, a measured value shows a favorable result, so that it is small.

Example 1: A tire according to the first embodiment shown in FIG.
Example 2: A tire according to the second embodiment shown in FIG.
Comparative example: tire obtained by removing small grooves from the first embodiment.

  From the results of Table 1, it can be seen that in the tires of Examples 1 and 2, the temperature rise of the center block is suppressed as compared with the tire of the comparative example.

(A) It is the top view which showed the tread pattern of the pneumatic tire which concerns on 1st Embodiment. (B) is the perspective view which expanded the small groove of FIG. 1 (A). (C) is a diagram showing the movement of the fluid flowing in the groove. (A) It is the top view which showed the tread pattern of the pneumatic tire which concerns on 2nd Embodiment. (B) is the perspective view which expanded the small groove of FIG. 2 (A). (C) is the figure which showed the motion of the fluid which flows through the inside of a groove | channel.

Explanation of symbols

10 Pneumatic tires for construction vehicles (pneumatic tires)
12 tread portion 14 tread rubber 16 width direction groove 18 circumferential direction narrow groove 20 width direction narrow groove 26 small groove 26A first small groove (small groove)
26B Second small groove (small groove)
CL equatorial plane

Claims (5)

Forming a tread portion in contact with the road surface, and a tread rubber having a thickness of 70 to 200 mm;
Provided in the tread portion, and a narrow groove having a groove width of 8 to 20 mm;
A small groove provided on a groove wall of the narrow groove, extending in a direction intersecting with a longitudinal direction of the narrow groove, and disturbing a flow of fluid in the narrow groove;
A pneumatic tire characterized by comprising: Forming a tread portion in contact with the road surface, and a tread rubber having a thickness of 70 to 200 mm;
A plurality of grooves provided on both tread end sides of the tread portion and extending in the tire width direction;
A plurality of narrow grooves provided between the widthwise grooves on both sides in the tire width direction and extending in the tire circumferential direction; and
A plurality of circumferential narrow grooves provided between the plurality of circumferential narrow grooves, extending in the tire width direction, and in which the groove walls are in contact with each other within the ground plane,
A small groove that is provided in a groove wall of the widthwise narrow groove, extends in a direction intersecting with a longitudinal direction of the widthwise narrow groove, and disturbs the flow of fluid in the widthwise narrow groove;
A pneumatic tire characterized by comprising:   The groove wall of the circumferential narrow groove is provided with a small groove that extends in a direction intersecting the longitudinal direction of the circumferential narrow groove and disturbs the flow of fluid in the circumferential narrow groove. The described pneumatic tire.   The pneumatic tire according to claim 2 or 3, wherein each of the width direction narrow grooves and the circumferential direction narrow grooves satisfy a width of 8 to 20 mm.   The groove depth of the small groove satisfies 20 to 100% of the groove depth of the narrow groove, the widthwise narrow groove, or the circumferential narrow groove in which the small groove is disposed. The pneumatic tire according to any one of 4.

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