JP2007331409A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire which makes performance on ice compatible with performance on snow at a high level with retaining the block rigidity of the tire by optimizing a lateral groove shape. <P>SOLUTION: In the tire, at least one block land part row 5 composed of a large number of block land parts 4 is defined/formed on a tread part 1 by arranging a plurality of lateral grooves 3 which communicate a plurality of circumferential direction grooves 2a to 2e extending to an approximately tire circumferential direction with adjacent two circumferential direction grooves 2a, 2b, and the tire is equipped with a plurality of sipes 6 extending so as to intersect the tire circumferential direction on the block land part 4. These lateral grooves 3 are composed of a wide width area 7 and a narrow width area 8 positioned at both sides of the wide width area 7. The tire is equipped with an enlargement part 9 having a larger groove width than an opening width w1 of the narrow width area 8 on the groove bottom side of the narrow width area 8. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In the tread portion, a plurality of block land portions are provided by disposing a plurality of circumferential grooves extending substantially in the tire circumferential direction and a plurality of lateral grooves communicating two adjacent circumferential grooves. A pneumatic tire, in particular, winter pneumatic, in which at least one block land portion row is formed and a plurality of sipes extending across the tire circumferential direction are arranged on the block land portion. The present invention relates to a tire, and aims to improve the running performance of the tire on an icy and snowy road surface.

  In order to eliminate dust pollution caused by spikes or studs protruding on the surface of the tread part, studless tires that do not have spikes and have excellent running performance on icy and snowy road surfaces have been developed.

  A feature that is almost common to studless tires is that the tread portion is divided into a large number of block land portions, and a large number of sipes are arranged. Increasing the number of such sipes increases the so-called edge effect, which is the effect of the edge of the block land scratching the road surface, and the so-called drainage effect, which is the effect of sipes sucking up the water film present on the ice road surface. Therefore, the performance on ice is improved. From the viewpoint of improving the performance on ice, it is preferable to increase the number of sipes disposed, but this may cause uneven wear of the block land portion at the same time. In order to prevent such uneven wear, for example, Patent Document 1 describes a tire in which an enlarged portion is formed at the bottom of a sipe and the enlarged portion is positioned lower than the bottom of the lateral groove. Patent Document 2 describes a tire that improves drainage while reducing irregular wear by providing a plurality of pits in the block land instead of sipe.

JP-A-7-172111 JP 2002-248906 A

  In order to improve the performance on ice, it is effective to increase the contact area during rolling of the tire and lower the negative rate. On the other hand, to improve the performance on snow, increase the groove area and increase the negative rate. It is very difficult to improve the performance on ice without almost deteriorating the performance on snow. In order to improve the performance on ice, it is effective to increase the number of sipes and increase the edge component of the sipe, but if the number of sipes is increased too much, the block rigidity decreases and the contact area decreases due to the bending deformation of the block. Rather, the performance on ice may deteriorate.

  Accordingly, an object of the present invention is to provide a pneumatic tire that achieves both high performance on ice and high performance on snow on the premise of maintaining the block rigidity of the tire by optimizing the lateral groove shape.

  In order to achieve the above object, according to the present invention, a plurality of circumferential grooves extending substantially in the tire circumferential direction and a plurality of transverse grooves communicating two adjacent circumferential grooves are disposed in the tread portion. By forming at least one block land portion row composed of a large number of block land portions, a plurality of sipes extending across the tire circumferential direction are disposed on the block land portion. In the tire, the lateral groove includes a wide area and a narrow area located on both sides of the wide area, and has an enlarged portion having a groove width larger than the opening width on the groove bottom side of the narrow area. It is a pneumatic tire characterized by. With this configuration, the narrow width region of the lateral groove suppresses the falling deformation of the block land portion and increases the ground contact area. On the other hand, by providing the enlarged portion, the lateral grooves communicate with each other to ensure drainage, and the lateral grooves are greatly opened outside the contact area, so that it is easy to discharge the snow grasped by the lateral grooves. Here, “substantially tire circumferential direction” means a direction in which an angle formed by an imaginary line connecting the center position of the groove width and the tire circumferential direction becomes ± 5 °, and “opening width” means a tread portion. It means the groove width measured along the tire circumferential direction on the tread.

  Moreover, it is preferable that the narrow area of the said lateral groove is obstruct | occluded in the contact area at the time of tire load rolling. Here, “simultaneous tire load rolling” means that the vehicle has traveled in a state where 80% of the maximum load load of the tire specified in JATMA is applied to the tire, and “contact area” means the tread portion. The area of the tread that is in contact with the road surface.

Furthermore, it is preferable that the opening width of the narrow width region of the lateral groove is 0.5 to 4.0 mm outside the contact area at the time of tire load rolling. Here, “outside the contact area” means an area other than the above “contact area” in the tread surface, that is, an area not in contact with the road surface.

  Furthermore, it is preferable that a wide area of the lateral groove is opened in a contact area at the time of tire load rolling.

In addition, in the contact area at the time of tire load rolling, it is preferable that the opening width of the wide area of the lateral groove is 1 to 10 mm.

  In addition, it is preferable that an opening width of the wide area of the lateral groove is 2 to 10 mm outside the contact area at the time of tire load rolling.

  Moreover, it is preferable that the depth from the tread portion tread surface to the enlarged portion of the lateral groove is 10 to 90% of the groove depth of the circumferential groove. Here, “depth” refers to the distance in the tire radial direction.

  Furthermore, it is preferable that the ratio of the length in the tire width direction of the wide width region to the sum of the lengths in the tire width direction of the narrow width regions on both sides is 1: 4 to 1: 4.

  Furthermore, it is preferable that a small hole is provided between a projecting end portion that is a portion projecting into the lateral groove in the tire circumferential end portion of the block land portion and a sipe adjacent to the projecting end portion in the same block land portion. In this case, the depth of the small hole is more preferably 10 to 90% of the depth of the circumferential groove. Here, “depth” refers to the distance in the tire radial direction from the road surface to the bottom of the small hole.

  According to the present invention, by optimizing the shape of the lateral groove, the collapse of the block land portion is suppressed, the contact area is increased, and the lateral groove is easily opened. It is possible to provide a pneumatic tire that achieves both high performance and performance on snow.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a development view of a block land portion row of a tread portion of a typical pneumatic tire (hereinafter referred to as “tire”) according to the present invention, and FIG. 2 is a perspective view of the block land portion of the tread portion shown in FIG. FIG. 3 is a cross-sectional view of the tire shown in FIG. 1 taken along the line III-III.

  The tire shown in FIG. 1 has a plurality of circumferential grooves extending substantially in the tire circumferential direction in the tread portion 1, two circumferential grooves 2a and 2b in FIG. 1 and two adjacent circumferential grooves 2a and 2b. By arranging a plurality of lateral grooves 3 communicating with each other, at least one block land portion row 5 including a plurality of block land portions 4 is partitioned. In this way, by arranging one or more block land portion rows, the groove area increases and the negative rate increases, so it is possible to ensure basic performance on snow.

  The block land portion 4 is provided with a plurality of sipes 6 that extend across the tire circumferential direction. As described above, when a plurality of sipes 6 extending across the tire circumferential direction are arranged on the block land portion 4, the edge component of the block land portion 4 increases, so that basic performance on ice is also ensured. Can do.

  In general, the lateral grooves are arranged with a uniform thickness. However, widening the opening width reduces the ground contact area during rolling of the tire and reduces the performance on ice, but the negative rate increases. The on-snow performance for scraping is improved. On the other hand, if the opening width of the lateral groove is uniformly narrowed, the contact area at the time of tire load rolling increases and the performance on ice improves, and if the lateral groove is further narrowed, the lateral groove functions as a sipe, and the edge effect However, on-snow performance decreases as the negative rate decreases. On the other hand, in the tire according to the present invention, a wide region 7 and a narrow region 8 having a narrower opening width are provided in one lateral groove 3. By providing such a narrow area 8, the block land portions 4 facing each other across the narrow width area 8 come into contact with each other and support each other, making it difficult for collapse to occur. Is suppressed. In addition, this simultaneously increases the contact area at the time of tire load rolling, thereby improving the performance on ice. On the other hand, the provision of the wide area 7 increases the amount of snow that the block land portion 4 facing the wide area 7 at the time of tire load rolling grips the road surface and improves the performance on snow.

  In addition, as shown in FIGS. 2 and 3, the tire according to the present invention includes an enlarged portion 9 having a groove width larger than the opening width w <b> 1 on the groove bottom side of the narrow width region 8. When the groove width of the narrow area 8 is uniform from the opening to the groove bottom, the so-called wiping action, in which the lateral groove grabs and scrapes snow, becomes small, and the performance on snow may deteriorate when soft snow such as fresh snow. However, when the enlarged portion 9 is provided on the groove bottom side of the narrow width region 8 as in the present invention, since the lateral groove width in the depth direction of the lateral groove 3 is widened, the lateral groove 3 is easily opened, and the wiping action is performed. The performance on the snow is improved especially when the snow quality is soft, such as fresh snow. Furthermore, even if the wear on the tread portion tread progresses and the wiping action decreases, the enlarged portion 9 appears on the tread portion tread, so that the performance on snow is maintained at a high level.

  Thus, in the tire according to the present invention, it is possible to achieve both the performance on ice and the performance on snow, which are conventionally considered to be a trade-off, at a high level. Furthermore, since the drainage performance can be improved while maintaining the rigidity of the block land portion 4, the wet performance and the dry handling performance are also improved.

  Moreover, it is preferable that the narrow width area 8 of the lateral groove 3 is closed in a contact area at the time of tire load rolling. Thereby, the falling deformation of the block land portion 4 in the contact area is suppressed, and the rigidity of the block land portion 4 can be more reliably maintained.

  Further, outside the contact area at the time of tire load rolling, the opening width w1 of the narrow width area 8 of the lateral groove is preferably 0.5 to 4.0 mm, more preferably 0.5 to 3.0 mm. is there. When the opening width w1 exceeds 4.0 mm, the negative rate of the tread portion tread increases and the drainage performance improves, but the block land portions 4 facing each other across the narrow width region 8 support each other. Incommensurate, collapsed deformation occurs, and as a result, a decrease in rigidity of the block land portion 4 cannot be suppressed, and the on-ice performance may not be improved. Further, when the opening width w1 is less than 0.5 mm, the negative rate of the tread portion tread decreases, so that the drainage performance is reduced, and the wide region 7 of the horizontal groove 3 of the block land portion 4 at the time of tire load rolling. When it comes into contact with the road surface, it is difficult to grasp snow, so the performance on snow may be reduced.

  Furthermore, it is preferable that the wide area 7 of the lateral groove 3 is opened in a contact area at the time of tire load rolling. This makes it easier for the block land portion 4 facing the wide groove 7 across the lateral groove during rolling to grab the ground when it is in contact with the ground to easily release the snow from the lateral groove 3 outside the contact area, further improving the performance on snow. Moreover, since the negative rate of a tread part tread increases, drainage property further improves.

  In addition, in the contact area at the time of tire load rolling, the opening width w2 of the wide area 7 of the lateral groove 3 is preferably 1.0 to 10.0 mm, more preferably 2.0 to 9.0 mm. . This adjusts to an appropriate amount of snow that the block land portion 4 facing the wide groove wide region 7 across the horizontal groove 7 at the time of rolling on the tire grips at the time of ground contact, and the performance on snow is further improved. When the opening width w2 of the wide area 7 of the lateral groove 3 exceeds 10.0 mm in the contact area at the time of tire load rolling, the opening width w2 is widened, so the negative rate of the tread portion tread increases, and the drainage performance In addition, the amount of snow that the block land 4 facing the wide groove 7 across the lateral groove 7 at the time of rolling tire load increases when it touches the ground, improving on-snow performance. 4 may be accompanied by a decrease in rigidity and on-ice performance. On the other hand, when the opening width w2 of the wide area 7 of the lateral groove 3 is less than 1.0 mm in the contact area at the time of tire load rolling, the opening width w2 is narrowed, and the negative rate of the tread portion tread is reduced. The rigidity of the land portion 4 is improved. However, since the amount of snow gripped by the block land portions 4 facing each other across the wide area 7 is reduced, there is a possibility that the performance on the snow and the drainage performance are deteriorated. From these points of view, it is preferable that the opening width w2 of the wide region 7 of the lateral groove 3 in the contact area at the time of tire load rolling is set to the above range from the viewpoint of balancing the performance on ice and the performance on snow.

  On the other hand, it is preferable that the opening width w2 of the wide region 7 of the lateral groove 3 is 2.0 to 10.0 mm, more preferably 3.0 to 10.0 mm, outside the contact area at the time of tire load rolling. According to this, the snow that the block land 4 facing the wide groove 7 across the wide groove 7 at the time of tire load rolling is more easily released to the outside outside the contact area, and the performance on snow is further improved. To do. If the opening width w2 of the wide area 7 of the lateral groove 3 exceeds 10.0 mm outside the contact area at the time of tire load rolling, the opening width w2 widens, so that the lateral groove wide area 7 is sandwiched at the time of tire load rolling. Thus, the snow picked up in the contact area by the opposing block land portion 4 can be easily discharged outside the contact area, and the performance on snow is improved. However, since the negative rate of the tread portion tread increases, there is a possibility that the rigidity of the block land portion 4 is lowered. On the other hand, when the opening width w2 of the wide region 7 of the lateral groove 3 is less than 2.0 mm outside the contact area at the time of tire load rolling, the rigidity of the block land portion 4 is reduced by reducing the negative rate of the tread surface. Will improve. However, since it is difficult to release the snow grasped by the block land portion 4 facing the wide area 7, the performance on snow may be deteriorated. From these points of view, it is preferable to set the opening width w2 of the wide region 7 of the lateral groove 3 outside the contact area at the time of tire load rolling within the above range from the viewpoint of balancing the performance on ice and the performance on snow.

  Further, the depth d from the tread portion tread surface to the enlarged portion 9 of the lateral groove 3 is preferably 10 to 90% of the groove depth of the circumferential groove, more preferably the groove depth of the circumferential groove. 20 to 80% of the thickness. As a result, the lateral groove 3 is easily opened and the wiping action is increased, and the on-snow performance is further improved particularly when soft snow such as fresh snow. Furthermore, even if the tread surface tread wears and the wiping action is reduced, the enlarged portion 9 appears on the tread surface, so that the drainage performance and on-snow performance are maintained at a high level. However, when the depth d is less than 10% of the groove depth of the circumferential groove, the length of the protruding end portion 10 in the tire radial direction is small and the wiping action is large, so that the performance on snow and the drainage performance are improved. However, since the rigidity of the block land portions 4 that are in contact with and support each other across the narrow width region 8 is lowered, the period until disappearance may be shortened due to wear caused by tire load rolling. Further, when the depth d exceeds 90% of the groove depth of the circumferential groove, the length of the protruding end portion 10 in the tire radial direction increases, which is in contact with each other across the narrow width region 8. While improving the rigidity of the block land portion 4 that supports and opposes and lengthens the period until it disappears due to wear caused by tire load rolling, it means that the enlarged portion becomes small, so the wiping action is small Therefore, drainage performance and snow performance may be degraded.

  Furthermore, the ratio of the width of the wide region 7 in the tire width direction to the length of the narrow region 8 in the tire width direction is preferably 1: 4 to 4: 1, more preferably 1: 3. .5 to 3.5: 1. As a result, the performance on snow and the performance on ice of the block land portion 4 facing each other across the wide groove region 8 and the narrow groove region 7 can be realized with a good balance. Because, when the length ratio is larger than 4: 1, that is, the length of the narrow width region 8 in the tire width direction is larger than four times the length of the wide width region 7 in the tire width direction. Although the on-ice performance is improved by increasing the narrow area, the on-snow performance may be significantly reduced because the wide area is excessively reduced at the same time. Further, when the ratio of the lengths is smaller than 1: 4, that is, when the length of the wide region 7 in the tire width direction is larger than four times the length of the narrow region 8 in the tire width direction. In this case, on-snow performance is improved by increasing the wide area, but at the same time the narrow-area is excessively reduced, so the on-ice performance may be significantly reduced.

  Furthermore, a small hole 11 is formed between the projecting end 10 which is a portion projecting into the lateral groove 3 in the tire circumferential direction end of the block land 4 and the sipe 6 adjacent thereto in the same block land 4. Is preferably provided. By providing the small hole 11, the drainage performance is improved as compared with the case where the rigidity of the block land portion 4 is not lowered and the protruding end portion is not provided, rather than the sipe 6 newly provided. Performance, wet performance, and dry handling performance are further improved.

  In this case, the depth of the small hole 11 is preferably 10 to 90% of the groove depth of the circumferential groove, and more preferably 20 to 80% of the groove depth of the circumferential groove. This is because when the depth of the small hole 11 is less than 10% of the groove depth of the circumferential groove, the volume of the small hole 11 becomes too small to obtain a sufficient water absorption effect, so that sufficient performance on ice can be obtained. If the wear on the tread surface further progresses, the small holes 11 may disappear at an early stage, making it difficult to maintain the expected performance. On the other hand, the depth of the small holes 11 may be the groove depth of the circumferential groove. In the case of exceeding 90%, the water absorption effect is sufficiently secured, but the handling performance on the dry road surface and the wet road surface is lowered due to the decrease in the rigidity of the block land portion 4, or the tread portion tread is grounded on the road surface. This is because the water taken into the small holes 11 at this time is not completely discharged from the small holes 11 due to the centrifugal force during the rotation of the tire, and the water absorption effect may be lowered in the course of rotation.

  The diameter of the opening of the small hole 11 is 0.5 to 4.0 mm, and preferably 0.5 to 3.0 mm. Because, when the opening diameter is less than 0.5 mm, only the rigidity of the block land portion is lowered, and both the water absorption effect and the edge effect are not exhibited, and the sufficient performance on ice may not be obtained. This is because, when the opening diameter exceeds 4.0 mm, the water absorption effect is improved, but when the edge effect is applied, the ground contact area is reduced and the performance on ice may be lowered. 1 and 2 show an embodiment in which the cross-section of the small hole 11 in the tire width direction is circular, the cross-sectional shape is not limited to this, and an elliptical cross-section or a non-circular cross-section can also be used.

  In the block land portion row 5 shown in FIG. 1, the lateral grooves 3 having a uniform groove width and the lateral grooves 3 having the features of the present invention are alternately provided, but depending on the required performance on ice and snow. A plurality of the lateral grooves 3 having the features of the present invention may be arranged every other, and like the tread pattern of the tire of the embodiment of the present invention shown in FIG. All the lateral grooves 3 may be the lateral grooves 3 having the features of the present invention. Further, as shown in FIG. 1, the shape of the block land portion 4 and the protruding end portion 10 when viewed in plan is a rectangle, but the shape is appropriately changed to various shapes used for conventional tires. May be.

  The above description shows only a part of the embodiment of the present invention, and these configurations can be combined alternately or various changes can be made without departing from the gist of the present invention.

  Next, the tire of the present invention having the tread pattern shown in FIG. 4 (Example) and the tire having the tread pattern of the prior art tire shown in FIG. 5 (conventional example) were respectively prototyped and subjected to performance evaluation. Therefore, it will be described below.

  The tire of the conventional example shown in FIG. 5 has a tread portion 1 defined by five circumferential grooves 2c, 2d, and 2e, and a central land portion having a pair of circumferential ribs 12 on both sides of the tire equatorial plane E. 13, a pair of shoulder land portions 14 disposed on the outer side in the tire width direction, and an intermediate land portion 15 disposed between the land portions, and two peripheries adjacent to the intermediate land portion 15 By arranging a plurality of lateral grooves 3 communicating with the direction grooves 2d and 2e, a block land portion row 5 composed of a large number of block land portions 4 is defined, and the entire tread portion tread crosses the tire circumferential direction. A plurality of sipes 6 extending in the manner are arranged.

  Further, in the tire of the embodiment shown in FIG. 4, in addition to the shape of FIG. 5 described above, the lateral grooves 3 are located at the wide width region 7 having a relatively large opening width, and at both ends of the wide width region 7, so The narrow width area 8 is provided with an enlarged portion 9 having a groove width larger than the opening width of the narrow width area 8 similar to that shown in FIG.

Each of these prototype tires is a 205 / 65R15 passenger car radial tire, and has the following specifications.
Negative rate: 29% (Example), 31% (Conventional example)
Sipe tire circumferential width: 0.4mm
The groove width of the tire circumferential groove between the two circumferential ribs: 10.0 mm
Groove width of tire circumferential groove sandwiched between shoulder land and intermediate land: 7.0 mm
Groove width of tire circumferential groove sandwiched between central land and intermediate land: 4.0 mm
Shoulder land width in the tire circumferential direction: 28.0mm
Middle circumferential tire circumferential width: 26.0mm
Circumferential rib width in the tire width direction: 10.5mm
Horizontal groove width in the tire circumferential direction: 6.0 mm

Moreover, the lateral groove and small hole of the tire of an Example become the following specifications.
The opening width in the tire circumferential direction of the wide area: 4.0 mm
Opening width in the tire circumferential direction of narrow area: 1.5mm
Opening width in the tire circumferential direction at the enlarged portion on the groove bottom side of the narrow width portion: 4.0 mm
Depth in the tire radial direction until reaching the enlarged part on the groove bottom side of the narrow part: 4.5 mm
Small hole: 3 each at the protruding end of the block land, diameter 1.2mm, depth 4.5mm

Each of the test tires was mounted on an actual vehicle, and the following evaluations were performed.
Feeling on snow: A professional driver comprehensively evaluated the braking performance, starting performance, straight running performance, and cornering performance when running on a test track on a snowy road surface.
On-snow braking performance: The braking distance when full braking was performed from a speed of 40 km / h on a pressure snow road surface was measured and evaluated based on the measurement result.
Traction on snow: The time required to travel a distance of 50 meters was measured after the accelerator was fully opened from a stopped state on a test track on a snowy road surface, and the measurement result was evaluated.
Feeling on ice: A professional driver comprehensively evaluated the braking performance, startability, straightness, and cornering on an ice road test course.
Braking on ice: A braking distance was measured when full braking was performed at a speed of 20 km / h on an ice road surface, and the measurement result was evaluated.
Dry road handling: When driving on a dry road test course in various driving modes, handling was evaluated by a professional driver.

  Table 1 shows the evaluation results of these tests. In addition, the evaluation result of Table 1 is shown by the index ratio when the tire evaluation result of a conventional example is set to 100, and performance is excellent, so that a numerical value is large.

  As shown in the results of Table 1, the tires of the examples had improved performance on snow, performance on ice, and dry handling performance as compared with the tires of the conventional examples.

  As has become apparent from the above inventions, to provide a pneumatic tire having both on-ice performance and on-snow performance at a high level on the premise of maintaining the tire block rigidity by optimizing the lateral groove shape. Became possible.

FIG. 3 is a development view of a part of a block land portion row of a tread portion of a typical tire according to the present invention. It is a perspective view of the block land part shown in FIG. It is sectional drawing on the III-III line of the block land part shown in FIG. FIG. 3 is a development view of a part of a tread portion of a tire according to an embodiment. It is an expanded view of the tread part of the tire of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread part 2a, 2b, 2c, 2d, 2e Circumferential groove | channel 3 Horizontal groove | channel 4 Block land part 5 Block land part row | line | column 6 Sipe 7 Wide area 8 Narrow area 9 Enlarged part 10 Projection end part 11 Small hole 12 Circumferential rib 13 Center Land 14 Shoulder Land 15 Middle Land

Claims (10)

By arranging a plurality of circumferential grooves extending substantially in the tire circumferential direction and a plurality of lateral grooves communicating with two adjacent circumferential grooves in the tread portion, at least one comprising a plurality of block land portions. In a pneumatic tire formed by partitioning a block land portion row of rows and arranging a plurality of sipes extending across the tire circumferential direction in the block land portion,
The lateral groove includes a wide area and a narrow area located on both sides of the wide area, and an enlarged portion having a groove width larger than the opening width of the narrow area is provided on the groove bottom side of the narrow area. Pneumatic tire characterized by   The pneumatic tire according to claim 1, wherein a narrow area of the lateral groove is closed in a contact area at the time of tire load rolling.   The pneumatic tire according to claim 1 or 2, wherein an opening width of a narrow area of the lateral groove is 0.5 to 4.0 mm outside a contact area at the time of tire load rolling.   The pneumatic tire according to any one of claims 1 to 3, wherein a wide area of the lateral groove opens in a contact area at the time of tire load rolling.   The pneumatic tire according to any one of claims 1 to 4, wherein an opening width of a wide area of the lateral groove is 1.0 to 10.0 mm in a contact area at the time of tire load rolling.   The pneumatic tire according to any one of claims 1 to 5, wherein an opening width of a wide area of the lateral groove is 2.0 to 10.0 mm outside a contact area at the time of tire load rolling.   The pneumatic tire according to any one of claims 1 to 6, wherein a depth from the tread portion tread surface to an enlarged portion of the lateral groove is 10 to 90% of a groove depth of the circumferential groove.   The ratio of the length in the tire width direction of the wide width region to the sum of the lengths in the tire width direction of the narrow width regions on both sides is 1: 4 to 4: 1. Pneumatic tire described in 2.   The small hole is provided between the projecting end part which is a part which protrudes in a horizontal groove among the tire circumferential direction edge parts of a block land part, and the sipe adjacent to this in the same block land part. A pneumatic tire according to claim 1.   The pneumatic tire according to claim 9, wherein a depth of the small hole is 10 to 90% of a groove depth of the circumferential groove.

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