JP4425064B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire suitable for all seasons with improved traction / brake performance and handling stability on snow.

  In order to improve the steering stability on the dry road surface and the uneven wear property on tire running, various devices have been conventionally made (see, for example, Patent Documents 1 to 6).

  Of these, it is probable that a rib-like land portion that is substantially continuous in the tire circumferential direction is disposed in the central region of the tread portion of the tire to increase the block rigidity of the central region.

  However, the edge effect of the block end with respect to the road surface on the snow is reduced in the central region of the tread part, and there is a problem that the traction / brake performance and the handling stability on the snow are deteriorated.

  In order to improve the traction / brake performance on the snow and the handling stability, as shown in FIG. 4, the central region 109 of the tread portion 107 of the tread portion 106 is divided by a lateral groove (lug groove) 108 extending substantially in the tire radial direction. By arranging the block rows 116L and 116R extending in the tire circumferential direction, it is conceivable to increase the edge effect of the block end on the road surface on snow.

However, there is a concern that the block rigidity is lowered in the central region 109 of the tread portion 107 of the tread portion 106, the steering stability on the dry road surface is deteriorated, and the tire uneven wear property is deteriorated.
Japanese Patent Laid-Open No. 5-238211 EP0544235 Japanese Patent Laid-Open No. 3-15561 EP0056457 US4416317 JP-A-8-276708

  In consideration of the above-described facts, the present invention provides a pneumatic tire with improved traction / brake performance and steering stability on a snowy road surface without reducing block rigidity in the central region of the tread surface. This is the issue.

The invention according to claim 1 is a pneumatic tire having at least one row of block rows partitioned by main grooves extending substantially in the tire circumferential direction in a central region of the tread portion of the tread portion. Lug grooves that divide the block row into blocks are formed, and each block has at least one sipe that divides into a block portion on one main groove side and a block portion on the other main groove side; Each block is adjacent to the one main groove side by forming at least one sipe that is divided into a block portion on one lug groove side and a block portion on the other lug groove side. At least two pseudo blocks, and at least two pseudo blocks adjacent to the other main groove side, and the shapes of the pseudo blocks adjacent to the one main groove side are substantially the same. To have the same shape of the pseudo-blocks adjacent to the main groove side of the other is also a substantially identical to each other, and each shoulder land portions constituting the tread portion is continuous with the substantially circumferential direction of the tire It is a rib and includes a lug groove extending from the ground contact end side and a lug groove extending from the shoulder main groove side, and both lug grooves are connected by a sipe extending from the lug groove end .

  The center region of the tread portion tread portion refers to a tread portion region whose width is within 60% of the tread width with the tire equator as the center line. The tread width is an interval between tread ends on both sides in the tire width direction. The tread end means that a pneumatic tire is mounted on a standard rim specified in JATMA YEAR BOOK (2002 edition, Japan Automobile Tire Association Standard), and the maximum load capacity (internal pressure) in the applicable size and ply rating in JATMA YEAR BOOK. -It indicates the outermost ground contact portion in the tire width direction when 100% of the air pressure (maximum air pressure) corresponding to the load capacity correspondence table is filled as the internal pressure and 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.

  Further, the main groove extending substantially in the tire circumferential direction refers to a main groove extending continuously in the tire circumferential direction without forming a narrow groove having a groove width smaller than 3 mm.

  Further, the pseudo block means that the edge is not entirely formed by a groove but has an edge partitioned by a sipe as described above and looks like a block when viewed from the tire surface.

  The shapes of the pseudo blocks are substantially the same as each other. The sides constituting the corresponding two blocks are inclined in the same direction, and the difference in the projected length of each side in the tire circumferential direction is common to all sides. Is within ± 60%, and the difference in the inclination angle of the side with respect to the tire width direction is within ± 10%.

  In the invention according to claim 1, by having at least one block row defined by main grooves extending substantially in the tire circumferential direction in the central region of the tread portion of the tread portion, the edge effect of the block end with respect to the road surface on snow is obtained. improves. This improves the traction / brake performance and handling stability on snow.

  Further, each block of the block row is formed by sipe with at least two pseudo blocks adjacent to one main groove side and at least two pseudo blocks adjacent to the other main groove side. The block rigidity of the central region of the tread surface can be increased without reducing the edge length of the block end. Therefore, the handling stability on the dry road surface is improved, and it can be used as a pneumatic tire for all seasons.

  Furthermore, the shapes of the pseudo blocks adjacent to one main groove side are substantially the same as each other, and the shapes of the pseudo blocks adjacent to the other main groove side are also substantially the same as each other. Accordingly, since the block rows in the tire circumferential direction are uniformly worn, uneven wear after running of the tire is improved (that is, uneven wear is difficult).

  In addition, it is preferable from the viewpoint of coexistence with the block rigidity of each block which comprises a tread part, and wet drainage that the main groove extended in a tire circumferential direction is three or four.

  Moreover, when the block pattern of the said block row is a pattern which appears repeatedly in a tire peripheral direction, it is preferable from a viewpoint that the wear form of each block which comprises a block row | line is uniform.

  The ribs substantially continuous in the tire circumferential direction are ribs arranged in the tire circumferential direction without being divided by lug grooves having a groove width of 2 mm or more.

If the shoulder land portion is not a rib that is substantially continuous in the tire circumferential direction but a block row that is divided by lug grooves extending from both sides of the ground contact end side and the shoulder main groove side, the block rigidity of the shoulder land portion The brake performance and uneven wear are likely to deteriorate. According to the first aspect of the present invention, it is possible to realize a pneumatic tire that sufficiently prevents the brake performance and uneven wear properties from being easily deteriorated.

In the invention according to claim 2 , the main groove formed in the central region is a main groove extending in a zigzag shape in the tire circumferential direction, and the shoulder main groove is a main groove extending in a zigzag shape in the tire circumferential direction. It is characterized by being.

  The term “zigzag extending in the tire circumferential direction” means that the groove portions extending in the same direction as the tire circumferential direction and the groove portions extending obliquely with respect to the tire circumferential direction are alternately extended in the tire circumferential direction. It is said that the groove portions extending in the same direction are arranged in a staggered manner.

  The phrase “zigzag extending in the tire circumferential direction” means that the groove portions inclined with respect to the tire circumferential direction extend in the tire circumferential direction with the inclination directions being alternated.

When the main groove formed in the central region extends in a staggered manner in the tire circumferential direction and the shoulder main groove extends in a straight line in the tire circumferential direction, the edge length of the block end with respect to the road surface on the snow is insufficient, and on the snow The traction / brake performance and steering stability are likely to deteriorate. According to the second aspect of the present invention, it is possible to realize a pneumatic tire that further prevents the brake performance and uneven wear property from being easily deteriorated.

The invention described in claim 3 is characterized in that the see-through width with respect to the groove width of the main groove extending in a zigzag shape and the main groove extending in a zigzag shape is 20% or more and 95% or less.

  When it is larger than 95%, the edge length of the block end with respect to the road surface on snow is insufficient, and the traction / brake performance on the snow and the steering stability are likely to deteriorate.

  Moreover, when it is less than 20%, the drainage property of the center region of the tread portion of the tread portion is deteriorated, and the high-pre performance and the wet steering stability are deteriorated.

According to the third aspect of the present invention, it is possible to realize a pneumatic tire with sufficiently improved traction / brake performance and steering stability on snow without reducing hydroplaning performance and wet steering stability.

The invention according to claim 4 is characterized in that a notch groove extending in the tire width direction is formed at each corner of the main groove extending in a zigzag shape.

  As a result, the edge length of the block end with respect to the road surface on snow can be further increased, and the traction / brake performance and steering stability on snow can be further improved.

Since the present invention is configured as described above, a pneumatic tire with improved traction / brake performance and steering stability on a snowy road surface without reducing block rigidity in the central region of the tread surface is realized. In addition, it is possible to realize a pneumatic tire that sufficiently prevents the brake performance and uneven wear from being easily deteriorated.

  Hereinafter, embodiments will be described and embodiments 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, the pneumatic tire 10 according to the present embodiment includes a carcass 12 extending in a toroidal shape, a belt 14 provided on the outer side of the crown portion of the carcass 12, and provided on the outer side of the belt 14. And a tread portion 16 connected in a toroidal manner between the wall portions.

  As shown in FIG. 2, staggered main grooves 20 </ b> L and 20 </ b> R that are symmetrical with respect to the tire equatorial plane CL and extend in the tire circumferential direction are formed in the central region 19 of the tread portion 17 of the tread portion 16. On the outer side in the tire width direction of the staggered main grooves 20L and 20R, zigzag main grooves 22L and 22R extending in the tire circumferential direction are formed as shoulder main grooves, respectively.

  The arrangement positions and shapes of the staggered main grooves 20L, 20R and the zigzag main grooves 22L, 22R are determined so as to be symmetric with respect to the tire equatorial plane CL.

  Accordingly, the central region 19 of the tread surface portion 17 is defined by the land portion 24 that is defined by the staggered main grooves 20L and 20R and located on the tire equator plane CL, and the staggered main groove 20L and the zigzag main groove 22L. The block row 26L thus formed and the block row 26R defined by the staggered main groove 20R and the zigzag main groove 22R are formed.

  As a result, the edge effect of the block end with respect to the road surface on the snow is improved, so that the traction / brake performance on the snow and the steering stability are improved.

  Further, the block row 26L and the block row 26R are formed in pairs so as to sandwich the tire equatorial plane CL. Furthermore, lug grooves 28 that cross the block row 26L and the block row 26R are formed in the central region 19, and each of the block rows 26L and 26R is configured by the blocks 30 being arranged in a row. . The lug grooves 28P and 28Q that define both sides of each block 30 in the tire circumferential direction have the same inclination angle with respect to the tire circumferential direction and are inclined in the same direction.

  Thereby, it is possible to improve the traction / brake performance and steering stability on snow regardless of the rotation direction of the tire.

  Since the configuration of the block string 26R is the same as that of the block string 26L, the block string 26L will be described in detail below, and the description of the block string 26R will be omitted.

  Each block 30 constituting the block row 26L is formed with a width direction groove 34L extending from the zigzag main groove 22L in the tire width direction and a width direction groove 34R extending from the staggered main groove 20L in the tire width direction. Yes.

  And the width direction sipe 36 which connects the width direction groove 34L and the width direction groove 34R is formed. As a result, each block 30 is a pseudo block 30P adjacent to the lug groove 28P when viewed from the tire surface side, It is divided into a pseudo block 30Q adjacent to the lug groove 28Q.

  Further, a circumferential groove 38L that extends in the tire circumferential direction and enters the pseudo block 30Q is formed at the tip of the width direction groove 34L, and a tip of the width direction groove 34R extends in the tire circumferential direction and enters the pseudo block 30P. A circumferential groove 38R is formed. Furthermore, circumferential grooves 42P and 42Q extending in the tire circumferential direction from the lug grooves 28P and 28Q, respectively, are formed in each block 30.

  The pseudo block 30P is formed with a sipe 46P that connects the tip of the circumferential groove 42P and the tip of the circumferential groove 38R. As a result, the pseudo block 30P has a zigzag main shape as viewed from the tire surface side. It is divided into a pseudo block 30A adjacent to the groove 22L and a pseudo block 30B adjacent to the staggered main groove 20L.

  Similarly, the pseudo block 30Q is formed with a sipe 46Q that connects the tip of the circumferential groove 42Q and the tip of the circumferential groove 38L. As a result, the pseudo block 30Q has a zigzag shape as viewed from the tire surface side. It is divided into a pseudo block 30C adjacent to the main groove 22L and a pseudo block 30D adjacent to the staggered main groove 20L.

  With such a structure, the block 30 includes pseudo blocks 30A to 30D as viewed from the tire surface.

  As a result, the rigidity of the block 30 is increased, and accordingly, the block rigidity of the central region 19 is increased, and the steering stability on the dry road surface is improved. Moreover, in this embodiment, since the sipe is provided in all the land part row | line | column 24 and block row | line 26L, 26R which comprise the tread part 16, it prevented fully that it became easy to deteriorate brake performance and uneven wear property. The pneumatic tire 10 that is optimal for all seasons can be obtained.

  Here, the width direction groove 34L extends from the tire circumferential center position of the block groove wall adjacent to the zigzag main groove 22L, and the width direction groove 34R is a block groove wall tire adjacent to the staggered main groove 20L. It extends from the circumferential center position. The circumferential groove 42P and the circumferential groove 38L have substantially the same dimensions, and the circumferential groove 42Q and the circumferential groove 38R have substantially the same dimensions. As a result, the pseudo block 30A and the pseudo block 30C adjacent to the zigzag main groove 22L have the same shape, and the pseudo block 30B and the pseudo block 30D adjacent to the staggered main groove 20L have the same shape. .

  Thereby, since the block row | line | column of a tire peripheral direction wears uniformly, the uneven wear property after tire driving | running | working improves.

  Further, the pseudo block 30P is formed with a pair of width direction cutout grooves 48L and 48R extending in the tire width direction from the zigzag main groove 22L and the staggered main groove 20L, respectively, and the end of the width direction cutout grooves 48L and 48R. Sipes 50L and 50R further extend from the ends. The same applies to the pseudo block 30Q. Thereby, the length of the edge part of the block end with respect to the road surface on snow increases, and the traction / brake performance on snow and steering stability further improve.

  Further, the shoulder land portions 54L and 54R are ribs that are substantially continuous in the tire circumferential direction. The shoulder land portion 54L includes a lug groove 58L extending from the ground contact end side and a lug groove 58R extending from the zigzag main groove 22L. The lug grooves 58L and 58R are connected by a sipe 56 extending from the end of the lug groove. Yes. The shoulder land portion 54R has the same configuration. Thereby, it can fully prevent that brake performance and uneven wear property become easy to deteriorate.

  Further, the staggered main grooves 20L and 20R are formed in the central region 19, and the zigzag main grooves 22L and 22R are formed as the shoulder main grooves. This also tends to deteriorate the brake performance and uneven wear characteristics. Can be sufficiently prevented.

  In this embodiment, the see-through width with respect to the groove width of the zigzag main grooves 22L and 22R and the staggered main grooves 20L and 20R is set to 20% or more and 95% or less. Thereby, the traction / brake performance on snow and steering stability can be sufficiently improved without degrading the hydroplaning performance and wet steering stability.

  Further, the lug groove 54L extends from each convex portion 60 on the shoulder land portion 54L side of the zigzag main groove 22L, and the tread portion 16 has a shoulder land portion from each concave portion 62 on the shoulder land portion 54L side. A notch groove 68 extending to 54L is further formed. On the other hand, on the central region 19 side of the zigzag main groove 22L, lug grooves 28P or 28Q are formed at the convex portions, and cutout grooves 48L are formed at the concave portions. Therefore, the lugs or notches are formed so as to communicate with the convex portions and the concave portions of the zigzag main groove 22L. The same applies to the zigzag main groove 22R. As a result, the edge length of the block end with respect to the road surface on snow can be further increased, and the traction / brake performance and steering stability on snow can be further improved.

[Second Embodiment]
Next, a second embodiment will be described. As shown in FIG. 3, in the pneumatic tire according to the present embodiment, a block row continuous in the tire circumferential direction is formed in the central region 79 of the tread portion 76 of the tread portion 76 as compared to the first embodiment. Absent.

  A zigzag main groove 80 that is located on the tire equator plane and extends in the tire circumferential direction is formed in the center region 79 of the tread portion 76 of the tread portion 76. On the outer side in the tire width direction of the staggered main groove 80, zigzag main grooves 82L and 82R extending in the tire circumferential direction are formed as shoulder main grooves, respectively.

  Accordingly, the central region 79 includes a block row 86L defined by the staggered main groove 80 and the zigzag main groove 82L, and a block row 86R defined by the staggered main groove 80 and the zigzag main groove 82R. The tire equatorial plane CL is formed in pairs.

  The block row 86L is configured by blocks 90 partitioned by a zigzag main groove 82L, a staggered main groove 80, and lug grooves 88P and 88Q arranged in a row. The lug grooves 88P and 88Q have the same inclination angle with respect to the tire circumferential direction and are inclined in the same direction. The block row 86R has the same configuration.

  The shape of each block 90 is an enlarged shape of the block 30 described in the first embodiment, and similarly to the first embodiment, circumferential grooves, width grooves, sipes, and the like are formed. It consists of two pseudo blocks 90A-D.

  In the present embodiment, the width (length in the tire width direction) of the shoulder land portions 94L and 94R is slightly longer than that in the first embodiment.

  According to the present embodiment, the rigidity of all the blocks 90 constituting the tread portion 76 is increased, and the steering stability on the dry road surface is further improved. Further, since the block end length and the sipe length of the block 90 are reduced as compared with the first embodiment, the traction / brake performance on snow and the steering stability are reduced as compared with the first embodiment, but the conventional embodiment. Compared with, the traction / brake performance and handling stability on snow are improved in each aspect.

<Test example>
The inventor first performed a performance test using a conventional pneumatic tire (PSR 245/75 R16) having a tread width of 187 mm.

  As shown in FIG. 4, the conventional pneumatic tire has four main grooves in the tread portion 106, and the see-through width of the linear main grooves 110L and 110R in the central region 109 of the tread portion 107 is 100%. A tire was used in which the number of lug grooves 108 crossing the block rows 116L and 116R was 80, and the shoulder land portions 114L and 114R were in the block row. Here, the see-through width of the main groove is a value obtained by dividing the minimum width of the main groove by the maximum width of the main groove. Table 1 shows the tread conditions.

試験条件としては、走行車に空気入りタイヤを取付け、タイヤ内圧を２２０ｋＰａとし、前席に２名乗車した条件とした。そして、（１）ドライ路面での操縦安定性、（２）雪上路面でのトラクション性、（３）雪上路面でのブレーキ性、（４）雪上路面での操縦安定性、（５）走行後の偏磨耗性、の５つの項目について測定し、何れも基準値として指数１００とした。これらを表２に示す。

As test conditions, a pneumatic tire was attached to the traveling vehicle, the tire internal pressure was set to 220 kPa, and two people got on the front seat. And (1) Steering stability on dry road surface, (2) Traction property on snowy road surface, (3) Brake property on snowy road surface, (4) Steering stability on snowy road surface, (5) After running The five items of uneven wear were measured, and all of them were set to an index of 100 as a reference value. These are shown in Table 2.

また、本発明者は、第１実施形態に係る空気入りタイヤ１０として、タイヤ規格及びトレッド幅が上記の従来の空気入りタイヤと同じで、トレッド部１６の主溝の本数を４本、踏面部１７の中央領域１９の千鳥状主溝２０Ｌ、２０Ｒのシースルー幅を６６％、中央領域１９のブロック列２６Ｌ、２６Ｒを横断するラグ溝の本数を４０本、ショルダ陸部５４Ｌ、５４Ｒの形態を連続リブとしたタイヤを製造し、実施例１の空気入りタイヤ１０とした。このトレッド条件を表１に併せて示す。

In addition, the present inventor, as the pneumatic tire 10 according to the first embodiment, has the same tire standard and tread width as the above-described conventional pneumatic tire, and the number of main grooves of the tread portion 16 is four, and the tread portion. Seventeen staggered main grooves 20L and 20R in the central region 19 have a see-through width of 66%, the number of lug grooves crossing the block rows 26L and 26R in the central region 19 is continuous, and the shape of the shoulder land portions 54L and 54R is continuous. A tire with ribs was manufactured, and the pneumatic tire 10 of Example 1 was obtained. The tread conditions are also shown in Table 1.

  And the performance test was done like the conventional pneumatic tire using the pneumatic tire 10 of this Example 1, and the index used as the relative evaluation with respect to the conventional pneumatic tire was computed about said five items. The calculated index is also shown in Table 2. Table 2 shows that the larger the index, the better the performance.

  Further, the present inventor, as a pneumatic tire according to the second embodiment, the number of main grooves of the tread portion 76 is 5, the see-through width of the staggered main groove 80 of the central region 79 of the tread portion 77 is 66%, A tire is manufactured in which the number of lug grooves crossing the block rows 86L and 86R in the central region 79 is 40, and the shape of the shoulder land portions 94L and 94R is a continuous rib continuous in the tire circumferential direction. Tire. The tread conditions are also shown in Table 1.

  And the performance test was similarly performed using the pneumatic tire of this Example 2, and the index used as the relative evaluation with respect to the conventional pneumatic tire was computed about said five items. The calculated index is also shown in Table 2.

  In the above evaluation, (1) Steering stability on a dry road surface was evaluated based on the feeling of the driver when driving on a circuit course with a dry road surface in various driving modes. (2) The traction on the snowy road surface was evaluated by the time (time) required to travel a distance of 50 m after starting on a snowy road surface. (3) The braking performance on the snowy road surface was evaluated by the braking distance when sudden braking (sudden braking) was applied during traveling at a speed of 40 km / h on the snowy road surface. (4) Steering stability on the snowy road surface was evaluated by the overall feeling of braking performance, startability, straightness, and cornering performance on the test track of snowy snowy road surface. (5) For uneven wear after running, measure the amount of wear step between adjacent blocks in the tire circumferential direction and the difference in wear between the tire center area and the shoulder area after running 5000 km on a general road surface. evaluated. Note that the smaller the difference in the amount of wear step and the amount of wear, the better the performance of uneven wear.

  As can be seen from Table 2, the pneumatic tire 10 of Example 1 has an evaluation result that it is better than the conventional pneumatic tire for any of the items, and in particular, it is good for uneven wear after running. It was a result. In addition, the pneumatic tire of Example 2 also has an evaluation result that it is better than the conventional pneumatic tire for any item, and the pneumatic tire 10 of Example 1 has a steering stability on a dry road surface. Better than.

  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. Needless to say, the scope of rights of the present invention is not limited to the above embodiment.

It is a tire radial direction sectional view showing the composition of the pneumatic tire concerning a 1st embodiment. It is a fragmentary top view which shows the tire surface shape of the pneumatic tire which concerns on 1st Embodiment. It is a fragmentary top view which shows the tire surface shape of the pneumatic tire which concerns on 2nd Embodiment. It is a fragmentary top view which shows the tire surface shape of the conventional pneumatic tire.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Pneumatic tire 16 Tread part 17 Tread part 19 Center area | region 20L, R Staggered main groove (main groove extended in zigzag form in the tire circumferential direction)
22L, R Zigzag main groove (main groove extending zigzag in the tire circumferential direction)
26L, R Block row 28P, 28Q Lug groove 30A-D, P, Q Pseudo block 30 Block 36 Sipe 46P, Q Sipe 48L, R Width direction notch groove (notch groove)
50L, R sipe 54L, R shoulder land 56 sipe 58L, R lug groove (groove)
60 Convex (corner)
62 Recess (corner)
68 Notch groove
76 Tread portion 77 Tread surface portion 79 Central region 80 Staggered main groove (main groove extending in a staggered manner in the tire circumferential direction)
82L, R Zigzag main groove (main groove extending zigzag in the tire circumferential direction)
86L, R block row 88P, Q lug groove 90 blocks 90A-D pseudo block 94L, R shoulder land portion 106 tread portion 107 tread portion 108 lug groove 109 central region 110L, R linear main groove 112L, R linear main groove 114L , R shoulder land 116L, R block row CL tire equator

Claims (4)

A pneumatic tire having at least one row of block rows partitioned by main grooves extending substantially in the tire circumferential direction in the central region of the tread portion of the tread portion,
Lug grooves that divide the block row into blocks are formed in the central region,
Each block includes at least one sipe that is divided into a block portion on one main groove side and a block portion on the other main groove side, a block portion on one lug groove side, and a block portion on the other lug groove side And at least one sipe that is divided into at least two pseudo blocks adjacent to the one main groove side and at least adjacent to the other main groove side. It consists of two pseudo blocks,
The shapes of the pseudo blocks adjacent to the one main groove side are substantially the same as each other,
The shape of the pseudo block adjacent to the other main groove side is also substantially the same as each other , and each shoulder land portion constituting the tread portion is a rib that is substantially continuous in the tire circumferential direction. A pneumatic tire comprising a lug groove extending from a grounding end side and a lug groove extending from a shoulder main groove side, wherein both lug grooves are connected by a sipe extending from a lug groove end . The main groove formed in the central region is a main groove extending in a staggered manner in the tire circumferential direction,
The pneumatic tire according to claim 1, wherein the shoulder main groove is a main groove extending in a zigzag shape in the tire circumferential direction . 3. The pneumatic tire according to claim 2 , wherein a see-through width with respect to a groove width of each of the staggered main grooves and the zigzag main grooves is 20% or more and 95% or less . The pneumatic tire according to claim 2 or 3 , wherein a notch groove extending in the tire width direction is formed at each corner of the main groove extending in a zigzag shape . It is.

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