JP5144178B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire optimal for use in an automobile traveling on a snowy road.

  Conventionally, in winter pneumatic tires (studless tires, for example, see Patent Documents 1 to 3), when running on a snowy road, the tire cannot easily grip the snowy road and the tire easily slips on the snow surface. there were.

  As measures against this, the area of the groove portion of the tire tread pattern has been increased in order to improve acceleration at the time of starting on a snowy road (acceleration on snow), braking on snow, and snow handling.

However, when the area of the groove portion is increased, the area of the tire portion that comes into contact with ice decreases, so that the performance on ice required for a winter pneumatic tire is lowered. For this reason, there is a limit in improving the performance on snow while achieving both the performance on snow and the performance on ice depending on the area of the groove.
JP-A-9-136516 JP-A-10-203121 JP 2000-127716 A

  In view of the above fact, an object of the present invention is to provide a pneumatic tire with improved performance on snow without increasing the groove area of the tread pattern.

  The present inventor conducted the following examination on the mechanism of the expression of the friction coefficient μ on the snow of the tire.

  As shown in FIG. 9, from the snow road surface, compression resistance FA, driving force or braking force by edge effect (hereinafter referred to as edge effect FD), surface friction force FC, and snow column shear force FB (snow column S). Is acting on the tire T. Here, the compression resistance FA is the force that the front of the tire presses against the snow surface and becomes running resistance, the edge effect FD is the force generated by the block edge or sipe edge scratching the snow road surface, the surface friction force FC is the rubber surface and the snow road surface The frictional force between them and the snow column shearing force FB indicate the force generated in the tire by shearing the snow in the lug groove. Note that the snow column shear force FB is generated by a mechanism that rotates the gears of the block land portion and the lug groove portion.

  Therefore, the present inventor has studied to improve on-snow performance without increasing the area of the groove. Then, the inventors have intensively studied to increase the longitudinal force generated in the tire by increasing the edge effect by devising the tread pattern configuration, and conducted further studies to complete the present invention.

In the first aspect of the present invention, a plurality of blocks defined by a rib groove along the tire circumferential direction and a lug groove intersecting the rib groove are formed in the tread portion, and a plurality of sipes are formed in the block. In the formed pneumatic tire, the tread portion is formed with a facing pattern by a pair of blocks sandwiching the lug groove, and in the blocks adjacent to each other in the tire width direction, the tire circumferential direction of the sipe position varies from each other, the tire circumferential direction position of the sipe are different from each other in all the blocks between which is positioned in the tire width direction, the facing pattern is a pattern that is axisymmetric across the lug grooves, wherein The tread pattern of the tread portion is symmetrical with respect to the tire equatorial plane, and the block on the lug groove side inside the tire circumferential direction of the facing pattern is In the portion, the sipe density is higher than the lug groove side on the outer side in the tire circumferential direction of the facing pattern, and the lug groove width on the inner side in the tire circumferential direction of the facing pattern is equal to the lug groove width on the outer side in the tire circumferential direction of the facing pattern. It is characterized by being narrower than that .

In the invention according to claim 1, the positions of the sipe in the tire circumferential direction are different from each other in blocks adjacent to each other in the tire width direction. Therefore, the time during which the sipe edge (the edges of a plurality of small blocks formed by the sipe) is caught on the snow road surface (scratching time) is greatly increased compared to the conventional case, so the performance on snow (especially the driving performance) is large. improves. In addition, since noise generated by scratching the sipe edge is dispersed, noise felt by the occupant during traveling is reduced. And since the tire circumferential direction position of Sipe is different from each other in all the blocks located in the tire width direction, it is possible to further improve the performance on snow and further reduce the noise felt by the occupant during traveling. it can.

In addition, the tread pattern function is separated on the inside of the facing pattern (the inside of the facing pattern in the tire circumferential direction) and on the outside of the facing pattern (the outside of the facing pattern in the tire circumferential direction), thereby improving the acceleration on snow and the braking performance on snow. It can be performed. Moreover, since it is not necessary to give directionality to this facing pattern, it is not necessary to specify the tire rotation direction, so that rotation of four tires is possible. And since the facing pattern is line-symmetric with the lug groove in between, the effect of the facing pattern is equivalent even if the rotation direction of the tire is changed. Each can be improved.
In addition, the tread pattern of the tread is symmetrical with respect to the tire equatorial plane, preventing pattern steer when braking force or driving force is applied to the tire and twisting the belt to prevent slip angle. Since there is no sticking and no lateral force is generated, the handling on snow is not deteriorated.
Furthermore, since the sipe density is higher in the block portion on the lug groove side on the inner side in the tire circumferential direction of the facing pattern than on the lug groove side on the outer side in the tire circumferential direction of the facing pattern, a small block formed by sipe The width in the tire circumferential direction is smaller on the lug groove side on the inner side in the tire circumferential direction of the facing pattern than on the lug groove side on the outer side in the tire circumferential direction of the facing pattern. Therefore, on the lug groove side on the inner side in the tire circumferential direction of the facing pattern, the small block is greatly collapsed, and the edge effect is particularly great during acceleration on snow. Further, on the lug groove side on the outer side in the tire circumferential direction of the facing pattern, the rigidity of the edge portion of the small block is large, and the edge effect is particularly great at the time of lock braking during snow braking.
And since the width of the lug groove on the inner side in the tire circumferential direction of the facing pattern is narrower than the width of the lug groove on the outer side in the tire circumferential direction of the facing pattern, the small lug groove separating the lug groove on the inner side in the tire circumferential direction of the facing pattern Since the block interval becomes small and supports each other when the small blocks collapse, it is possible to prevent the edge effect from being lowered due to excessive collapse. In addition, the width of the lug groove is increased on the outer side in the tire circumferential direction of the facing pattern, and the snow column shear force can be effectively exhibited.

The invention according to claim 2 is characterized in that the facing pattern is formed at least in a tire center portion.

  Thereby, the edge effect by the facing pattern can be effectively exhibited in the tire center portion where the contact length becomes large.

  In the present invention, the block shape of the tread pattern is not limited to the case where the rib groove and the lug groove are orthogonal to each other, and can naturally be applied to the case where the groove has an oblique groove. Further, the present invention is not limited to the case where the block edge direction and the sipe direction are parallel to each other. Further, the sipe may be a plate sipe, or may be a width direction amplitude sipe extending with amplitude on the block surface. Further, it may be a depth direction amplitude sipe (three-dimensional sipe) extending in the block depth direction.

  ADVANTAGE OF THE INVENTION According to this invention, it can be set as the pneumatic tire which improved on-snow performance, without increasing the groove part area of a tread pattern.

  Hereinafter, a studless tire for a passenger car will be cited as an embodiment, and an embodiment of the present invention will be described. In the second and subsequent embodiments, the same components as those already described are denoted by the same reference numerals, and description thereof is omitted.

[First Embodiment]
First, the first embodiment will be described. As shown in FIG. 1, a pneumatic tire 10 according to the present embodiment includes a carcass (for example, radial carcass) 12 composed of one layer or a plurality of layers that are folded at bead cores 11 at both ends and straddle in a toroidal shape. ing.

  On the outer side in the tire radial direction of the crown portion 12C of the carcass 12, a belt layer 14 in which a plurality of (for example, two) belt plies are stacked is embedded.

  A tread portion 16 provided with a groove is formed on the outer side of the belt layer 14 in the tire radial direction. As shown in FIG. 2, a plurality of rib grooves (main grooves) 22 along the tire circumferential direction U are formed in the tread portion 16. The tread portion 16 is formed with a plurality of lug grooves 24 that intersect the tire circumferential direction. In the present embodiment, the lug groove 24 is orthogonal to the rib groove 22, and the lug groove 24 is formed along the tire width direction V. Both end portions of each lug groove 24 communicate with the rib groove 22 or extend beyond the tread end T so as to be drained outward in the tire width direction.

  Here, the tread end means that a pneumatic tire is mounted on a standard rim specified in JATMA YEAR BOOK (2006 edition, Japan Automobile Tire Association Standard), and the maximum load in the applicable size and ply rating in JATMA YEAR BOOK. Fills 100% of the air pressure (maximum air pressure) corresponding to the capacity (internal pressure-load capacity correspondence table) as the internal pressure, and indicates the outermost contact portion in the tire width direction when the maximum load capacity is applied. In addition, when TRA standard and ETRTO standard are applied in a use place or a manufacturing place, it follows each standard.

  The tread portion 16 includes a center block row 30C having a center line on the tire equatorial plane CL and a second block row adjacent to both outer sides in the tire width direction of the center block row 30C. 32L and 32R, and shoulder block rows 34L and 34R respectively located on both outer sides in the tire width direction of the second block rows 32L and 32R are formed.

  In order to form such a block row, center main grooves 22L and 22R are formed as rib grooves 22 between the center block row 30C and the second block rows 32L and 32R, respectively, and the second block rows 32L and 32R and the shoulders are formed. Shoulder main grooves 22P and 22Q are formed between the block rows 34L and 34R, respectively.

  Further, as the lug grooves 24, narrow narrow lug grooves 24 </ b> N and wide wide lug grooves 24 </ b> W are alternately arranged in the tire circumferential direction U.

In the center block row 30C, the facing pattern 20 is formed by a pair of blocks 26C and 27C that are symmetric with respect to the narrow lug groove 24N. A sipe 28 along the tire width direction V is formed in the blocks 26C and 27C. In the blocks 26C and 27C, more sipes 28 are formed on the narrow lug groove 24N side than on the wide lug groove 24W side. Accordingly, the sipe density is higher in the block portion on the narrow lug groove 24N side than in the block portion on the wide lug groove 24W side. The sipe interval is the same interval d in the blocks 26C and 27C. The distance between the narrow lug groove side block wall 26I adjacent to the narrow lug groove 24N and the sipe 28 closest to the narrow lug groove side block wall 26I is also d.

  By arranging the sipe 28 in this way, the narrow block 26N is arranged in the tire circumferential direction U in the block portion on the narrow lug groove 24N side (facing pattern inside). The width D of the small block 26W in the block portion on the side of the wide lug groove 24W (outside the facing pattern) is wider than the width d of the small block 26N, and the rigidity of the small block 26W is higher than that of the small block 26N. .

  In the second block row 32L, as in the center block row 30C, the facing pattern 20 is formed by a pair of blocks 26L and 27L. The positions in the tire circumferential direction of the blocks 26L and 27L are shifted by d / 4 in the tire circumferential direction U compared to the blocks 26C and 27C.

  In the second block row 32R, as in the center block row 30C, the facing pattern 20 is formed by a pair of blocks 26R and 27R. The arrangement positions of the blocks 26R and 27R in the tire circumferential direction are shifted by d / 2 in the tire circumferential direction U compared to the blocks 26C and 27C.

  The dimensions of the blocks 26C, 27C, 26L, 27L, 26R, and 27R are the same. Accordingly, by shifting the block position in the tire circumferential direction in this way, the positions of the sipe in the tire circumferential direction are different from each other in all the blocks located in the tire width direction V. That is, the sipe position is shifted by d / 4 between the block 26C and the block 26L, and the sipe position is also shifted by d / 4 between the block 27C and the block 27L. Further, the sipe position is shifted by d / 2 between the block 26C and the block 26R, and the sipe position is also shifted by d / 2 between the block 27C and the block 27R. Further, the sipe position is shifted by d / 4 between the block 27L and the block 27R, and the sipe position is also shifted by d / 4 between the block 27L and the block 27R.

(Function, effect)
Hereinafter, the operation and effect of this embodiment will be described. As shown in FIG. 4, when a tire travels on a snowy road, each block causes the edge portion 26NE of the small block 26N and the edge portion 26WE of the small block 26W to enter snow while receiving the compression resistance FA. Dig up snow.

  At the time of acceleration, when the slip ratio is large and the collapse of the small block becomes large, the blocks adjacent to each other across the narrow-width lug groove 24N, that is, the pair of blocks forming the facing pattern 20 are small blocks 26N. Support each other while falling down. As a result, the edge effect FD is effectively exhibited while maintaining an appropriate amount of collapse. Further, since the rigidity of the small block 26W is high, the rigidity of the edge portion 26WE of the small block 26W is large. Therefore, at the time of braking, the block can be prevented from falling down and the ground contact surface can be prevented from rising particularly at the time of lock braking, and the edge effect is effectively exhibited.

  Further, when running on a snowy road, the snow is pressed into the wide lug groove 24W to form a snow column S, and the snow column S is sheared at the wide lug groove side block wall 26K as the tire rolls. As a result, a snow column shearing force FB is generated. In order to improve on-snow performance without increasing the groove area, it is necessary to increase the edge effect FD and the snow column shear force FB. In the present embodiment, both the edge effect and the snow column shear force can be effectively generated by the facing pattern 20.

  Moreover, in this embodiment, the sipe density is higher in the block portion on the inner side of the facing pattern (on the narrow lug groove side) than on the block portion on the outer side of the facing pattern (on the wide lug groove side). With this configuration, the width d of the small block 26N formed on the inner side of the facing pattern (on the narrow lug groove side) is smaller than the width D of the small block 26W formed on the outer side of the facing pattern. Therefore, the small block 26N falls greatly inside the facing pattern, and the edge effect is particularly great during acceleration on snow. Further, outside the facing pattern, the rigidity of the edge portion 26WE of the small block 26W is large, and the edge effect FD is particularly large during lock braking during snow braking. Therefore, the tire with improved on-snow performance can be obtained without increasing the groove area of the tread pattern, that is, without sacrificing on-ice performance.

  Further, by shifting the block position in the tire circumferential direction for each block row, the tire circumferential direction position of the sipe is different from each other in all the blocks located in the tire width direction V. Accordingly, since the sipe edge is always caught on the snow road surface, performance on snow (especially driving performance) is remarkably improved. Further, since noise generated by scratching the edge portions 26NE and 26WE is dispersed, noise felt by the occupant during traveling is reduced.

  Moreover, the function of the tread pattern can be separated between the facing pattern inside and the facing pattern outside, and the pattern design for improving the snow acceleration and snow braking performance can be performed. Moreover, since it is not necessary to give direction to the facing pattern 20, there is no need to specify the tire rotation direction (the traveling direction shown in FIG. 3, the traveling direction at the time of back), so that rotation of the four wheels of the tire is possible. It is.

  Further, a narrow lug groove 24N is formed inside the facing pattern, and a wide lug groove 24W is formed outside the facing pattern. As a result, the interval between the small blocks separating the narrow lug grooves 24N (that is, the width BN of the narrow lug grooves 24N) becomes small and supports when the small blocks collapse, so the edge effect is reduced due to excessive collapse. Can be prevented. Further, on the outside of the facing pattern, the interval BW between the small blocks separating the wide lug grooves 24W (that is, the width BW of the wide lug grooves 24W) becomes large, and the snow column shear force FB can be effectively exhibited.

  Further, since the facing pattern 20 is formed by the center block row 30C constituting the tire center portion, the edge effect by the facing pattern 20 can be effectively exhibited in the tire center portion where the contact length becomes large.

[Second Embodiment]
Next, a second embodiment will be described. As shown in FIG. 5, in the present embodiment, a second block row 32L is arranged instead of the second block row 32R as compared to the first embodiment. Accordingly, the tread pattern is symmetrical with respect to the tire equatorial plane CL.

  As a result, pattern steer is prevented from occurring when a braking force or driving force is applied to the tire, and the belt is not twisted to cause a slip angle. Accordingly, since no lateral force is generated, the steering stability on snow does not deteriorate.

<Test example>
In order to confirm the effect of the present invention, the inventor has an example of a pneumatic tire according to the first embodiment (hereinafter referred to as an example tire) and an example of a conventional pneumatic tire (hereinafter referred to as a conventional tire). And an example of a pneumatic tire for comparison (hereinafter referred to as a tire of a comparative example) was prepared, and performance was evaluated by performing a performance test on snow.

  In the conventional tire, as shown in FIG. 10, a block 76 is formed in the tread portion 77 instead of the blocks 26C, 27C, 26L, 27L, 26R, and 27R, as compared with the tire of the embodiment. Further, in the conventional tire, a lug groove 84 having the same width is formed.

  In the tire of the comparative example, as shown in FIG. 11, the blocks constituting the center block row 90C are the same as the block 76 as compared with the conventional tire, but the block 96L constituting the second block row 92L and the second block The blocks 96R constituting the block row 92R are different. Also in the tire of the comparative example, the lug groove 84 having the same width is formed as in the conventional tire.

  In this test example, the negative rate was 35% for all tires.

  As for the block dimensions, in the tire of the example, as shown in FIG. 3, the tire circumferential direction length L is 20 mm, the tire width direction length M is 20 mm, the tire radial direction depth (block height) H is 9 mm, The depth h of the sipe 28 is 7.5 mm, the width J of the small block 26 is 3.0 mm, the width BN of the narrow-width lug groove 24N is 2 mm, and the width BW of the wide-width lug groove 24W is 7 mm.

  In the conventional tire, the outer dimensions of the block 76 (the values of L, M, and H shown in FIG. 3) are the same as those of the tire of the example. Further, sipes 78 are formed at equal intervals in the block 76. The dimensions of the sipe 78 are the same as the sipe 28. In the center block row 70C and the second block rows 72L and 72R forming the tread portion 77, the tire circumferential direction position of the sipe 78 is the same.

  In the conventional tire, the tread pattern is symmetrical with respect to the tire equatorial plane CL as shown in FIG. 10 in order to make the tread pattern bilaterally symmetrical (the tread pattern is symmetrical on the tire inner side and the tire outer side). Is forming. Therefore, the tire circumferential direction position of the sipe 78 is the same in the center block row 72C and the second block rows 72L and 72R. For this reason, compared with the tire of an Example, the time when the sipe edge is caught on the snow road surface is significantly short. Moreover, since all the lug groove widths are the same, the function cannot be separated between the block portion 76A on one side in the tire circumferential direction and the block portion 76B on the other side in the tire circumferential direction of each block 76.

  In the tire of the comparative example, the outer dimensions (the values of L, M, and H shown in FIG. 3) of the blocks 96L and 96R are the same as those of the tire of the example. In the block 96L, the sipe density on one side in the tire circumferential direction (the lower side in the drawing of FIG. 11) is high. In the block 96R, the sipe density on the other side in the tire circumferential direction (the upper side in the drawing of FIG. 11) is high. The dimensions of the sipe 98 formed in the blocks 96L and 96R are the same as those of the sipe 28.

  In the tire of the comparative example, a tread pattern that is point-symmetric with respect to a point on the tire equatorial plane CL is formed as shown in FIG. In this tread pattern, the pattern is asymmetrical with respect to the tire equatorial plane CL. Therefore, when a braking force or a driving force is applied to the tire, pattern steer is generated, and the belt is twisted to add a slip angle, thereby generating a lateral force. Will occur. For this reason, especially on-snow handling stability tends to deteriorate.

  In each tire, four tires were arranged in the block so that sipes substantially parallel to the block edge portion were formed.

  In this test example, for all tires, the tire size is 195 / 65R15, it is assembled to the rim of 6J-15 and the internal pressure is 200 kPa, and it is attached to a passenger car and loaded with a normal load. Tests of braking performance and snow handling stability were conducted. Here, the “regular load” refers to the maximum load in the application size / ply rating defined in the 2006 YEAR BOOK issued by JATMA.

  In the on-snow acceleration test, the evaluation was performed based on the time (acceleration time) until the accelerator was fully opened from a stationary state and traveled 50 m. Then, the evaluation index based on the running time of the tire of the conventional example was set to 100, and the evaluation index for relative evaluation was calculated for the tires of the example and the comparative example. The evaluation results are shown in Table 1.

雪上制動性の試験では、３０ｋｍ／ｈの走行状態でフルブレーキをかけて静止状態になるまでの制動距離を計測した。そして、従来例のタイヤの制動距離に基づく評価指数を１００とし、実施例、比較例のタイヤについて相対評価となる評価指数を算出した。評価結果を表１に併せて示す。

In the on-snow braking performance test, the braking distance until a stationary state was reached by applying a full brake in a traveling state of 30 km / h was measured. Then, the evaluation index based on the braking distance of the tire of the conventional example was set to 100, and the evaluation index for relative evaluation was calculated for the tires of the example and the comparative example. The evaluation results are also shown in Table 1.

  In the snow handling stability test, sensory evaluation (feeling evaluation) was performed by a test driver. At that time, the evaluation index based on the feeling of the tire of the conventional example was set to 100, and the evaluation index for relative evaluation was calculated for the tires of the example and the comparative example. The evaluation results are also shown in Table 1.

  Table 1 shows that the larger the evaluation index, the higher the performance. As can be seen from Table 1, in the tires of the examples, the evaluation index was higher in all tests of snow acceleration, snow braking, and snow handling stability than the conventional tires and the comparative tires. . Therefore, without increasing the groove area of the tread pattern, that is, without sacrificing the performance on ice, the tires of the embodiment in which the tread pattern configuration is devised, the performance on snow (acceleration on snow, snow braking performance, snow safety) ) Could be improved.

  The embodiments of the present invention have been described above with reference to the embodiments. However, these embodiments are merely examples, and various modifications can be made without departing from the scope of the invention.

  In addition, it is good also as a tire which shifted only the sipe position, maintaining the sipe space | interval d at equal intervals, without shifting a block position. For example, as shown in FIG. 6, the tire circumferential direction positions of the blocks are the same in the center block row 40C and the second block rows 40L and 40R. Then, in the center block row 40C, the position of the sipe 28 is shifted upward by d / 4 with respect to the second block row 42R, and in the second block row 42L, the position of the sipe 28 is lowered with respect to the second block row 42R. Shift by d / 4. Thereby, the narrow lug groove 24N and the wide lug groove 24W can be positioned on the straight line in the tire width direction V.

  Further, the sipe intervals may be non-uniform. For example, as shown in FIG. 7, the sipe interval d1 of the center block row 50C may be made wider than the sipe interval d2 of the second block rows 52L and 52R. Further, as shown in FIG. 8, in a pair of blocks forming the facing pattern 60, one block 66 may have a wide sipe interval d1, and the other block 67 may have a narrow sipe interval d2.

It is tire radial direction sectional drawing of the pneumatic tire which concerns on 1st Embodiment. It is a top view which shows the tread pattern of the pneumatic tire which concerns on 1st Embodiment. 3A and 3B are a plan view and a perspective view, respectively, showing that a facing pattern is formed by a pair of blocks in the pneumatic tire according to the first embodiment. 4A and 4B are a schematic partial side sectional view showing that the pneumatic tire rolls on a snow road surface, and a block in contact with the snow road surface, respectively, in the first embodiment. (The number of sipes is omitted in FIG. 4A. Also, the region with dots in FIG. 4B indicates the portion scratching the snow road surface). It is a top view which shows the tread pattern of the pneumatic tire which concerns on 2nd Embodiment. It is a top view which shows the tread pattern of the modification of the pneumatic tire which concerns on this invention. It is a top view which shows the tread pattern of the modification of the pneumatic tire which concerns on this invention. It is a top view which shows the tread pattern of the modification of the pneumatic tire which concerns on this invention. 9 (A) and 9 (B) are a schematic partial side sectional view showing that a conventional pneumatic tire rolls on a snow road surface, and a side sectional view of a block in contact with the snow road surface, respectively. (The number of sipes is omitted in FIG. 9 (A). In addition, the region marked with dots in FIG. 9 (B) shows a portion scratching the snow road surface). It is a top view which shows the tread pattern of the pneumatic tire of the prior art example used by the test example. It is a top view which shows the tread pattern of the pneumatic tire of the comparative example used by the test example.

Explanation of symbols

10 pneumatic tire 16 tread portion U tire circumferential direction 20 facing pattern 22 rib groove 24 lug groove CL tire equatorial plane 26C block 26L block 26R block 27L block 27C block 27R block 28 sipe 24W wide lug groove 24N narrow width lug groove BN width ( Lug groove width)
BW width (lug groove width)
V tire width direction 77 tread portion 76 block 78 sipe 84 lug groove 96L block 92R block 60 facing pattern 66 block 67 block

Claims (2)

A pneumatic tire in which a plurality of blocks defined by rib grooves along the tire circumferential direction and lug grooves intersecting the rib grooves are formed in the tread portion, and a plurality of sipes are formed in the blocks. And
In the tread portion, a facing pattern is formed by a pair of blocks sandwiching the lug groove,
And, in a block adjacent in the tire width direction, unlike the tire circumferential direction position of the sipes from one another,
The tire circumferential direction position of the sipe is different from each other in all the blocks located in the tire width direction,
The facing pattern is a pattern that is symmetric with respect to the lug groove,
The tread pattern of the tread portion is symmetrical with respect to the tire equatorial plane,
In the block portion on the lug groove side on the inner side in the tire circumferential direction of the facing pattern, the sipe density is higher than the lug groove side on the outer side in the tire circumferential direction of the facing pattern,
A pneumatic tire characterized in that a lug groove width on the inner side in the tire circumferential direction of the facing pattern is narrower than a lug groove width on the outer side in the tire circumferential direction of the facing pattern . The pneumatic tire according to claim 1, wherein the facing pattern is formed at least in a tire center portion.

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