JP5993400B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire having good wet performance and wear resistance.

  Patent Document 1 below proposes a heavy load tire in which a plurality of substantially hexagonal blocks are provided in a tread portion. This pneumatic tire is expected to have the effect of making the noise of the block against the road surface white noise by causing the edge of each block to collide with the road surface at different timings.

International Publication WO2010 / 055659

  However, in the tire of Patent Document 1, the contact pressure is concentrated on the edge of each block, and uneven wear such as heel-and-toe wear in which the portion wears early is likely to occur. On the other hand, a tire having a tread portion having a high land ratio has been proposed in order to increase the wear resistance, but this tire has a problem of having a low wet performance.

  The present invention has been devised in view of the above circumstances, and provides a pneumatic tire having good wet performance and wear resistance on the basis of improving the arrangement of the main groove and the sipe angle. The main purpose is to do.

  The present invention includes a pair of center main grooves extending continuously in the tire circumferential direction on both sides of the tire equator in the tread portion, and a pair of shoulders extending continuously in the tire circumferential direction on both sides of the tire equator and closest to the tread grounding end side. A main land groove, a center land portion between the pair of center main grooves, a pair of shoulder land portions on the outer side in the tire axial direction of the shoulder main groove, the center main groove and the shoulder main groove, A pneumatic tire provided with a pair of middle land portions between the center main groove and the shoulder main groove, the first protrusion projecting toward the tire equator side and the tread grounding end side, respectively. The pair of center main grooves increase or decrease the tire axial width of the center land portion in the tire circumferential direction. The shoulder main grooves are arranged such that the width of each middle land portion in the tire axial direction repeats increasing and decreasing in the tire circumferential direction. The width of the shoulder main groove is larger than the width of the center main groove, and the center land portion communicates between the pair of center main grooves and in the tire axial direction. A plurality of center sipes inclined at an angle θ1 of 5 to 25 ° with respect to the middle land portion are communicated between the center main groove and the shoulder main groove and with respect to the tire axial direction. A plurality of middle sipes inclined at an angle θ2 of 5 to 25 ° are provided, and the angle θ1 of the center sipe is larger than the angle θ2 of the middle sipes, and is provided in a middle land portion on the left side of the tire equator. And Midorusaipu that, the Midorusaipu provided on the right side of the middle land portion of the tire equator, is characterized in that it is inclined in opposite directions to each other.

  In the pneumatic tire of the present invention, the center sipe communicates between a first center sipe communicating between the first protrusions of the center main grooves and the second protrusion of the center main grooves. And a second center sipe.

  In the pneumatic tire of the present invention, the middle sipe includes a first middle sipe that communicates between the first protrusion of the center main groove and the second protrusion of the shoulder main groove, and the center main groove. It is desirable to include a second middle sipe that communicates between the second protrusion and the first protrusion of the shoulder main groove.

  In the pneumatic tire according to the present invention, it is preferable that each of the middle sipes is provided so as to be continuous with the center sipe via the center main groove.

  In the pneumatic tire according to the aspect of the invention, it is preferable that the center main groove has a groove width of the second protrusion larger than that of the first protrusion.

  In the pneumatic tire of the present invention, the second protrusion of the center main groove is bent in a direction in which the groove edge on the outer side in the tire axial direction protrudes outward in the tire axial direction, and the groove edge on the inner side in the tire axial direction is It is desirable to extend along the direction.

  In the pneumatic tire of the present invention, it is desirable that both the center sipe and the middle sipe are linear.

  In the pneumatic tire of the present invention, the shoulder land portion includes a plurality of shoulder sipes that communicate between the shoulder main groove and the tread grounding end and are inclined at an angle θ3 of 5 to 25 ° with respect to the tire axial direction. Preferably, the inner end of the shoulder sipe in the tire axial direction is located between the first protrusion and the second protrusion of the shoulder main groove.

  In the present invention, the groove width of the center main groove is formed smaller than the groove width of the shoulder main groove. As a result, the middle land portion approaches the center land portion side, and the land ratio in the vicinity of the tread central portion where a large load acts is increased. Therefore, each ground pressure of a center land part and a middle land part falls, and these abrasions are suppressed.

  On the other hand, if the land ratio near the center of the tread is increased, the wet performance may be reduced. The center main groove and the shoulder main groove of the present invention have a zigzag shape, and the substantial length of the groove in the ground contact surface is larger than the linear groove along the tire circumferential direction. Moreover, such center main grooves and shoulder main grooves exhibit an edge effect not only in the tire circumferential direction but also in the tire axial direction. Therefore, the tire of the present invention effectively maintains the wet performance near the center of the tread while having the center main groove with a small groove width.

  In the tire of the present invention, the width in the tire axial direction of the center land portion and the middle land portion repeatedly increases and decreases in the tire circumferential direction. For this reason, when the tread of each land part touches down, the part with the small width will bend moderately. Therefore, the partial distortion at the time of ground contact of the tread is effectively suppressed, and uneven wear of the center land portion and the middle land portion is suppressed.

  The center land portion is provided with a plurality of center sipes that communicate with each other between the pair of center main grooves and incline at an angle θ1 of 5 to 25 ° with respect to the tire axial direction. Each middle land portion is provided with a plurality of middle sipes that communicate with each other between the center main groove and the shoulder main groove and are inclined at an angle θ2 of 5 to 25 ° with respect to the tire axial direction. Such center sipe and middle sipe exhibit an excellent edge effect in the tire circumferential direction, and improve wet performance.

  In general, it is effective to make the wear of the center land portion having a high contact pressure close to the wear of the middle land portion in order to make the wear uniform. Since a larger ground pressure acts on the center land portion than on the middle land portion, it is important to relatively increase the wear resistance of the center land portion. In the present invention, the angle θ1 of the center sipe is larger than the angle θ2 of the middle sipe. Thereby, each land part piece divided by the center sipe contacts and supports each other with respect to any force in the tire circumferential direction and the tire axial direction. Therefore, the rigidity of the center land portion is increased, and the wear between the center land portion and the middle land portion becomes uniform.

  The middle sipe provided in the middle land portion on the left side of the tire equator and the middle sipe provided in the middle land portion on the right side of the tire equator are inclined in opposite directions. Such middle sipes exhibit an edge effect evenly on both sides in the tire axial direction. Moreover, such a middle sipe guides water between the middle land portion and the road surface to both outer sides in the tire axial direction during wet traveling. For this reason, in particular, straight running stability during wet traveling is enhanced.

  Therefore, the pneumatic tire of the present invention has good wet performance and wear resistance performance.

It is an expanded view of the tread part of the pneumatic tire of one embodiment of the present invention. It is AA sectional drawing of FIG. It is an enlarged view of the center land part of FIG. It is an enlarged view of the middle land part of FIG. It is BB sectional drawing of the 2nd middle sipe of FIG. It is an enlarged view of the shoulder land part of FIG. It is an expanded view of the tread part of the pneumatic tire of a comparative example.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a development view of a tread portion 2 of a pneumatic tire (hereinafter sometimes simply referred to as “tire”) 1 of the present embodiment. The pneumatic tire 1 of this embodiment is suitably used for heavy-duty vehicles such as trucks and buses, for example.

  The tread portion 2 of the present embodiment has a directional pattern in which the rotation direction R of the tire is specified. The rotation direction R is indicated by, for example, characters or marks on a sidewall portion or the like.

  As shown in FIG. 1, the tread portion 2 is provided with a pair of center main grooves 10 and 10 and a pair of shoulder main grooves 20 and 20. Accordingly, the tread portion 2 includes a center land portion 30 between the pair of center main grooves 10 and 10, a pair of middle land portions 40 between the center main groove 10 and the shoulder main grooves 20, and a shoulder main groove. A pair of shoulder land portions 50 on the outer side in the tire axial direction are divided.

  The pair of center main grooves 10, 10 extend continuously in the tire circumferential direction on both sides in the tire circumferential direction.

  Each center main groove 10 has a zigzag shape in which first protrusions 11 protruding to the tire equator C side and second protrusions 12 protruding to the tread ground contact Te side appear alternately in the tire circumferential direction.

  “Tread ground contact Te” means that a normal rim (not shown) is assembled with a rim and filled with a normal internal pressure, and a normal load is applied to a normal tire 1 that is unloaded, and a camber angle of 0 ° is applied. This is the contact position on the outermost side in the tire axial direction when contacting the plane.

  The “regular rim” is a rim determined for each tire in a standard system including a standard on which a tire is based. For example, “Standard Rim” for JATMA, “Design Rim” for TRA, For ETRTO, "Measuring Rim".

  The “regular internal pressure” is the air pressure determined by each standard for each tire in the standard system including the standard on which the tire is based, and is “maximum air pressure” for JATMA, and “TIRE LOAD” for TRA. The maximum value described in “LIMITS AT VARIOUS COLD INFLATION PRESSURES”, “INFLATION PRESSURE” in the case of ETRTO.

  The “regular load” is a load determined by each standard for each tire in the standard system including the standard on which the tire is based. “JAMATA” indicates “maximum load capacity”, and TRA indicates “TIRE” The maximum value described in “LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES”, or “LOAD CAPACITY” in the case of ETRTO.

  In the first protrusion 11, for example, an inner edge 11i in the tire axial direction and an outer edge 11o in the tire axial direction extend linearly along the tire circumferential direction. On the other hand, the second protrusion 12 is bent such that the groove edge 12o on the outer side in the tire axial direction protrudes outward in the tire axial direction, and the groove edge 12i on the inner side in the tire axial direction extends linearly along the tire circumferential direction. .

  The groove width W9 of the second protrusion 12 is desirably larger than the groove width W8 of the first protrusion 11, for example. Such a center main groove 10 smoothes the flow of water in the groove from the first protrusion 11 to the second protrusion 12 and improves wet performance.

  The pair of center main grooves 10, 10 are arranged with the zigzag phase shifted so that the width in the tire axial direction of the center land portion 30 repeatedly increases and decreases in the tire circumferential direction.

  The tread contact width TW is a distance in the tire axial direction between the tread contact ends Te and Te in the normal state.

  The groove width W1 of the center main groove 10 is, for example, 1.5 to 3.0% of the tread ground contact width TW. Such a center main groove 10 exhibits excellent wet performance while increasing the rigidity in the vicinity of the center portion of the tread.

  The center main groove 10 includes a first groove portion 13 inclined to one side with respect to the tire circumferential direction, and a second groove portion 14 inclined in the opposite direction to the first groove portion 13.

  An angle θ5 of the first groove portion 13 and the second groove portion 14 with respect to the tire circumferential direction is, for example, 5 to 25 °. Such a center main groove 10 exhibits an edge effect with a good balance with respect to the tire axial direction and the tire circumferential direction during wet running.

  FIG. 2 shows a cross-sectional view taken along line AA of the tread portion 2 of FIG. As shown in FIG. 2, the groove depth d1 of the center main groove 10 is, for example, 8 to 25 mm. Such a center main groove 10 exhibits excellent wet performance.

  As shown in FIG. 1, the pair of shoulder main grooves 20 and 20 are provided on both sides of the tire equator C and closest to the tread ground contact Te, and extend continuously in the tire circumferential direction.

  The shoulder main groove 20 has a zigzag shape in which first protrusions 21 protruding toward the tire equator C side and second protrusions 22 protruding toward the tread ground contact Te side appear alternately in the tire circumferential direction.

  The shoulder main groove 20 is arranged with the center main groove 10 and the zigzag phase shifted so that the width in the tire axial direction of each middle land portion 40 repeatedly increases and decreases in the tire circumferential direction.

  The width W2 of the shoulder main groove 20 is larger than the width W1 of the center main groove 10.

  As a result, the middle land portion 40 approaches the center land portion 30 side, and the land ratio in the vicinity of the tread central portion where a large load acts is increased. Accordingly, the ground pressures of the center land portion 30 and the middle land portion 40 are reduced, and wear of these is suppressed.

  On the other hand, if the land ratio near the center of the tread is increased, the wet performance may be reduced. The center main groove 10 and the shoulder main groove 20 of the present invention have a zigzag shape, and the substantial length of the groove in the contact surface is larger than the linear groove along the tire circumferential direction. Moreover, such center main grooves and shoulder main grooves exhibit an edge effect not only in the tire circumferential direction but also in the tire axial direction. Therefore, the tire of the present invention effectively maintains the wet performance near the center of the tread while having the center main groove 10 having a small groove width.

  In order to further improve the wet performance and wear resistance, the ratio W2 / W1 between the width W2 of the shoulder main groove 20 and the center main groove is preferably 1.8 or more, more preferably 2.0 or more. It is preferably 2.6 or less, more preferably 2.4 or less.

  When the center land portion 30 and the middle land portion 40 are continuously extended in the tire circumferential direction with a substantially constant width, there is no escape space in the tire circumferential direction of these land portions at the time of ground contact, and the deformation in the tire axial direction is not caused. growing. As a result, the treads of the center land portion 30 and the middle land portion 40 are partially distorted at the time of ground contact, and uneven wear may occur near the edge of the land portion. In the present invention, the center main groove 10 and the shoulder main groove 20 are arranged with their zigzag phases shifted so that the width in the tire axial direction of the center land portion 30 and the middle land portion 40 repeatedly increases and decreases in the tire circumferential direction. ing. For this reason, when the tread of each land portion is grounded, the portion having a small width is appropriately bent, so that partial distortion at the time of grounding of the tread is effectively suppressed, and uneven wear of the land portion is suppressed. The

  The shoulder main groove 20 includes a first groove portion 23 inclined to one side with respect to the tire circumferential direction and a second groove portion 24 inclined in the direction opposite to the first groove portion 23. An angle θ6 with respect to the tire circumferential direction of the first groove portion 23 and the second groove portion 24 is, for example, 5 to 25 °. Such a shoulder main groove 20 exhibits an edge effect with a good balance with respect to the tire circumferential direction and the tire axial direction.

  As shown in FIG. 2, the groove depth d2 of the shoulder main groove 20 is, for example, 8 to 25 mm.

  FIG. 3 shows an enlarged view of the center land portion 30. As shown in FIG. 3, the center land portion 30 is provided with a plurality of center sipes 32 that communicate between the pair of center main grooves 10 and 10. In this specification, “sipe” means a cut having a width of 0.5 to 1.0 mm, and is distinguished from a drainage groove. The center land portion 30 of the present embodiment is formed as a so-called rib in which a lateral groove having a groove width larger than that of the sipe is not provided.

  The distance W3 in the tire axial direction of the center land portion 30 is, for example, 0.15 to 0.25 times the tread ground contact width TW (shown in FIG. 1). Such a center land portion 30 improves wet performance and wear resistance in a well-balanced manner.

  The center sipe 32 is inclined linearly and inclined at an angle θ1 of 5 to 25 ° with respect to the tire axial direction. Such a center sipe 32 exhibits an excellent edge effect in the tire circumferential direction, and improves wet performance.

  As shown in FIG. 2, the depth d3 of the center sipe 32 is, for example, 0.7 to 0.9 times the groove depth d1 of the center main groove 10. Such a center sipe 32 improves wear resistance and wet performance in a well-balanced manner.

  As shown in FIG. 3, the center sipe 32 is formed between the first center sipe 33 communicating between the first protrusions 11 and 11 of the center main groove 10 and the second protrusions 12 and 12 of the center main groove 10. And a second center sipe 34 communicating therewith. The first center sipes 33 and the second center sipes 34 are arranged in parallel to each other and are alternately provided in the tire circumferential direction.

  FIG. 4 shows an enlarged view of the middle land portion 40. As shown in FIG. 4, the middle land portion 40 is provided with a plurality of middle lateral grooves 41 and a plurality of middle sipes 42.

  The distance W4 in the tire axial direction of the middle land portion 40 is, for example, 0.15 to 0.25 times the tread ground contact width TW. Such a middle land portion 40 improves wet performance and wear resistance in a well-balanced manner.

  The middle lateral groove 41 communicates between the center main groove 10 and the shoulder main groove 20. The groove width W6 of the middle lateral groove 41 is, for example, 0.30 to 0.45 times the groove width W1 of the center main groove 10.

  The middle sipe 42 is inclined linearly with an angle θ2 of 5 to 25 ° with respect to the tire axial direction. Such a middle sipe 42 exhibits an excellent edge effect in the tire circumferential direction and improves wet performance.

  The angle θ1 of the center sipe 32 (shown in FIG. 3 and the same applies hereinafter) is larger than the angle θ2 of the middle sipe 42.

  In general, it is effective to make the wear of the center land portion 30 having a high contact pressure close to the wear of the middle land portion 40 in order to make the wear uniform. Since a larger ground pressure acts on the center land portion 30 than the middle land portion 40, it is important to relatively improve the wear resistance of the center land portion 30. In the present invention, the angle θ1 of the center sipe 32 is larger than the angle θ2 of the middle sipe 42. Thereby, each land piece segmented by the center sipe 32 is in contact with each other and supported by any force in the tire circumferential direction and the tire axial direction. Therefore, the rigidity of the center land portion 30 is increased, and the wear of the center land portion 30 and the middle land portion 40 becomes uniform.

  As shown in FIG. 1, the middle sipe 42A provided on the middle land portion 40A on the left side of the tire equator C and the middle sipe 42B provided on the middle land portion 40B on the right side of the tire equator C are inclined in opposite directions. doing. Such a middle sipe 42 exhibits an edge effect evenly on both sides in the tire axial direction. Moreover, such a middle sipe 42 guides the water between the middle land portion and the road surface to both sides in the tire axial direction during wet traveling. For this reason, in particular, straight running stability during wet traveling is enhanced.

  For example, each middle sipe 42 is inclined outward in the tire axial direction from the first arrival side to the rear arrival side in the tire rotation direction R. Such a middle sipe 42 further improves wet performance.

  As shown in FIG. 4, the middle sipe 42 includes a first middle sipe 43 that communicates between the first protrusion 11 of the center main groove 10 and the second protrusion 22 of the shoulder main groove 20, and the center main groove 10. A second middle sipe 44 that communicates between the second protrusion 12 and the first protrusion 21 of the shoulder main groove 20 is included. Such first middle sipe 43 and second middle sipe 44 can effectively suppress partial distortion of the tread surface at the time of ground contact.

  FIG. 5 is a cross-sectional view of the second middle sipe 44 of FIG. 4 taken along the line BB. As shown in FIG. 5, the second middle sipes 44 are provided, for example, on the groove bottom 41 d of the middle lateral groove 41. Such a second middle sipe 44 can supplement the drainage of the middle lateral groove 41 and further improve the wet performance.

  The depth d4 from the tread surface 40s of the middle land portion to the bottom 44d of the second middle sipe 44 is, for example, not less than 0.7 times the groove depth d1 (shown in FIG. 2) of the center main groove 10, more preferably 0. It is 75 times or more, preferably 0.9 times or less, more preferably 0.85 times or less. Thereby, abrasion resistance and wet performance are improved with good balance.

  FIG. 6 shows an enlarged view of the shoulder land portion 50. As shown in FIG. 6, the shoulder land portion 50 is a block row in which shoulder blocks 55 divided by a plurality of shoulder lateral grooves 51 are arranged in the tire circumferential direction.

  For example, the shoulder lateral groove 51 communicates between the shoulder main groove 20 and the tread grounding end Te. For example, the shoulder lateral groove 51 is inclined at an angle θ7 of 5 to 25 ° with respect to the tire axial direction.

  The groove width W7 of the shoulder lateral groove 51 is, for example, 0.65 to 0.75 times the groove width W2 of the shoulder main groove 20. Such shoulder lateral grooves 51 effectively enhance wet performance while maintaining wear resistance.

  The shoulder block 55 has, for example, a substantially pentagonal tread surface 56. The tread surface 56 of the shoulder block 55 has an inner edge 57 that protrudes inward in the tire axial direction. As a result, the rigidity of the shoulder block 55 in the tire axial direction is enhanced, and the wear resistance of the block is enhanced.

  For example, a shoulder sipe 52 is provided in the shoulder block 55. For example, the shoulder sipe 52 communicates between the shoulder main groove 20 and the tread grounding end Te.

  For example, the shoulder sipe 52 is inclined at an angle θ3 of 5 to 25 ° with respect to the tire axial direction and extends linearly. Such a shoulder sipe 52 exhibits an excellent edge effect in the tire circumferential direction.

  As shown in FIG. 2, the depth d5 of the shoulder sipe 52 is, for example, 0.7 to 0.9 times the groove depth d2 of the shoulder main groove. Such a shoulder sipe 52 improves wet performance and wear resistance in a well-balanced manner.

  As shown in FIG. 6, the inner end 53 of the shoulder sipe 52 in the tire axial direction is preferably located between the first protrusion 21 and the second protrusion 22 of the shoulder main groove 20. Such a shoulder sipe 52 effectively suppresses uneven wear of the inner edge 57 of the shoulder block 55.

  Although the pneumatic tire of the present invention has been described in detail above, the present invention is not limited to the specific embodiment described above, and can be implemented with various modifications.

A heavy-duty tire of size 315 / 80R22.5 having the basic structure shown in FIG. As Comparative Example 1, as shown in FIG. 7, a tire in which the center main groove and the shoulder main groove have the same groove width and the center sipe and the middle sipe extend along the tire axial direction was manufactured. Each test tire was tested for uneven wear resistance and wet performance. The common specifications and test methods for each test tire are as follows.
Wearing rim: 7.50 × 22.5
Tire internal pressure: 800kPa
Test vehicle: 10t truck, 50% of the standard load capacity is loaded in front of the loading platform Tire mounting position: All wheels

<Abrasion resistance>
With the test vehicle, the remaining groove depth of the center main groove was measured when traveling on a general road for a certain distance. A result is displayed by the index | exponent which sets the comparative example 1 to 100, and shows that abrasion resistance is excellent, so that a numerical value is large.

<Wet performance>
With the test vehicle, the passage time when passing a test course with a total length of 10 m under the following conditions was measured. The evaluation is the reciprocal of the passage time, and is represented by an index with the value of Comparative Example 1 being 100. The larger the value, the shorter the passage time and the better the wet performance.
Road surface: Asphalt with a 5mm thick water film Start method: 2nd speed-1500rpm fixed, start with clutch connected.
The test results are shown in Table 1.

  As a result of the test, it was confirmed that the pneumatic tire of the present invention had good wet performance and wear resistance.

2 Tread part 10 Center main groove
20 shoulder main groove 30 center land part 32 center sipe 40 middle land part 42 middle sipe 50 shoulder land part

Claims (8)

A pair of center main grooves extending continuously in the tire circumferential direction on both sides of the tire equator and a pair of shoulder main grooves extending continuously in the tire circumferential direction on both sides of the tire equator and closest to the tread grounding end side in the tread portion. By being provided, a center land portion between the pair of center main grooves, a pair of shoulder land portions on the outer side in the tire axial direction of the shoulder main grooves, and a pair between the center main groove and the shoulder main grooves A pneumatic tire provided with a middle land portion of
The tread portion includes a directional pattern in which a tire rotation direction is designated,
Each of the center main groove and the shoulder main groove has a zigzag shape in which first protrusions protruding toward the tire equator side and second protrusions protruding toward the tread ground contact end side alternately appear in the tire circumferential direction. ,
In the center main groove, the groove width of the second protrusion is larger than the groove width of the first protrusion,
The pair of center main grooves are arranged by shifting the phase of each zigzag so that the width in the tire axial direction of the center land portion repeatedly increases and decreases in the tire circumferential direction,
The shoulder main groove is arranged by shifting the phase of the center main groove and zigzag so that the width in the tire axial direction of each middle land portion repeatedly increases and decreases in the tire circumferential direction,
The groove width of the shoulder main groove is larger than the groove width of the center main groove,
The center land portion is provided with a plurality of center sipes that communicate with each other between the pair of center main grooves and incline at an angle θ1 of 5 to 25 ° with respect to the tire axial direction.
Each middle land portion is provided with a plurality of middle sipes that communicate between the center main groove and the shoulder main groove and are inclined at an angle θ2 of 5 to 25 ° with respect to the tire axial direction.
The angle θ1 of the center sipe is larger than the angle θ2 of the middle sipe,
The middle sipe provided in the middle land portion on the left side of the tire equator and the middle sipe provided in the middle land portion on the right side of the tire equator are opposite to each other and from the first arrival side to the rear arrival side in the tire rotation direction. A pneumatic tire that is inclined outward in the tire axial direction .
  The center sipe includes a first center sipe that communicates between the first protrusions of the center main grooves and a second center sipe that communicates between the second protrusions of the center main grooves. The pneumatic tire according to claim 1.   The middle sipe includes a first middle sipe that communicates between the first protrusion of the center main groove and the second protrusion of the shoulder main groove, the second protrusion of the center main groove, and the shoulder main. The pneumatic tire according to claim 1, further comprising a second middle sipe that communicates with the first protrusion of the groove.   The pneumatic tire according to any one of claims 1 to 3, wherein each of the middle sipes is provided so as to be continuous with the center sipe via the center main groove. The air according to any one of claims 1 to 4, wherein the first protrusion of the center main groove has an inner edge in the tire axial direction and an outer edge in the tire axial direction extending along the tire circumferential direction. Enter tire.   The second projecting portion of the center main groove is bent so that a groove edge on the outer side in the tire axial direction protrudes outward in the tire axial direction, and a groove edge on the inner side in the tire axial direction extends along the tire circumferential direction. The pneumatic tire according to any one of 1 to 5.   The pneumatic tire according to any one of claims 1 to 6, wherein both the center sipe and the middle sipe are linear. The shoulder land portion includes a plurality of shoulder sipes that communicate between the shoulder main groove and the tread grounding end and are inclined at an angle θ3 of 5 to 25 ° with respect to the tire axial direction.
The pneumatic tire according to any one of claims 1 to 7, wherein an inner end of the shoulder sipe in the tire axial direction is located between the first protrusion and the second protrusion of the shoulder main groove. .

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