JP6632363B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire.

  In Patent Literature 1, a lateral groove having a narrow groove opening in the main groove and an extension groove extending outward from the end of the narrow groove in the tire width direction is formed in the shoulder rib located at the end in the tire width direction. A pneumatic tire is disclosed. The narrow groove is provided so as to bend from the main groove toward the front side in the tire rotation direction, and the extension groove is provided so as to extend in a direction orthogonal to the main groove. Further, the narrow groove is formed so that the groove width is narrower than the extension groove.

JP 2015-16751 A

  In the tire of Patent Literature 1, the dry performance can be improved while securing the wet performance by the lateral groove including the narrow groove and the extension groove. However, in this tire, there is room for improvement in the rigidity of the land portion partitioned in the tire circumferential direction by the lateral groove.

  An object of the present invention is to provide a pneumatic tire capable of suppressing occurrence of toe-heel uneven wear while optimally adjusting the rigidity of a land portion.

The present invention is characterized in that three or more ribs partitioned in the tire width direction by two or more main grooves extending in the tire circumferential direction, and a shoulder rib located on one end side in the tire width direction among the ribs, A plurality of grooves are provided at intervals in the tire circumferential direction, and a lateral groove extending in the tire width direction of the shoulder rib, and a land portion partitioned by the lateral groove in the tire circumferential direction of the shoulder rib is provided. A sipe extending in the tire width direction of the land portion, wherein the lateral groove extends from the outer end of the shoulder rib in the tire width direction toward the main groove, and a narrow groove extending toward the main groove from the main groove side end portion of the lateral groove body, said narrow groove has a narrow groove width than the lateral grooves body, relative to the transverse groove body is set tire A first sipe extending in the tire width direction of the land portion toward the main groove; and a main groove side end of the first sipe. A second sipe extending from a portion to the main groove, wherein the first sipe and the second sipe have a narrower groove width than the lateral groove main body, and the second sipe is the tire with respect to the first sipe. The lateral groove main body is formed to be bent rearward in the rotation direction, and the lateral groove body includes a first front wall located on the front side in the tire rotation direction, a first rear wall located on the rear side in the tire rotation direction, The narrow groove is defined by a front wall and a first bottom wall located inside the first rear wall in the tire radial direction, and the narrow groove is a second front wall located on the front side in the tire rotation direction, and the rear side in the tire rotation direction. , A second rear wall, and the tire diameter of the second front wall and the second rear wall Are defined by a second bottom wall which is located toward the inside, in the unused state, the first front bending point is an intersection of the first front wall of the tread surface side edge and the second front wall, the first A pneumatic pump which is located on a side of the shoulder rib farther from the main groove in the tire width direction than a first rear bending point which is an intersection of a tread surface side edge of the first rear wall and the second rear wall. Provide tires.

  According to this pneumatic tire, since the shoulder rib is provided with the lateral groove including the lateral groove main body and the narrow groove, the drainage performance of water can be improved. Further, since the lateral groove main body is communicated with the main groove through a narrow groove having a groove width smaller than that of the lateral groove main body, the contact length of the land portion can be extended without excessively reducing the rigidity of the land portion. Similarly, since the sipe having the first sipe and the second sipe, the groove width of which is smaller than that of the lateral groove, is provided in the land portion, the contact length of the land portion can be extended without excessively reducing the rigidity of the land portion. be able to. Therefore, the deformation of the land portion due to the lateral force during turning of the vehicle can be suppressed.

  In addition, the lateral groove is configured such that the bending points of the front wall and the rear wall are different from each other in the tire width direction of the shoulder rib. Specifically, the bending point on the front side (kick-out side) in the tire rotation direction where uneven wear is apt to occur is located at the center in the tire width direction of the shoulder rib where uneven wear does not easily occur, and the rear side in the tire rotation direction where uneven wear does not easily occur ( The bending point on the stepping side is located on the main groove side of the shoulder rib where uneven wear is likely to occur. Therefore, occurrence of toe-heel uneven wear can be reliably suppressed while the rigidity of the land portion is favorably adjusted (uniform).

  A front taper portion is formed on the first front wall and a rear taper portion is formed on the first rear wall so that a groove width of the lateral groove main body gradually decreases toward the first bottom wall. And a second front bending point, which is an intersection between the bottom edge of the front taper portion located on the first bottom wall side and the second front wall, is the rear side located on the first bottom wall side. The shoulder rib is located on the main groove side in the tire width direction of the shoulder rib from a second rear bending point which is an intersection of the bottom side edge of the tapered portion and the second rear wall. According to this aspect, as the wear of the land part progresses by use, the positions of the bending points of the front wall and the rear wall of the lateral groove change. When the land portion is worn to a position where the tapered portion is eliminated, the bending point of the front wall is located closer to the main groove than the bending point of the rear wall, contrary to the unused state. Therefore, occurrence of toe-heel uneven wear during a period in which uneven wear may occur can be significantly suppressed. Further, the groove area of the lateral groove main body is reduced with the wear of the tapered portion, and the contact area of the land portion is increased. Since the rigidity (block rigidity) of the land portion is improved by increasing the ground contact area of the land portion, the braking distance, which is one of dry performances, can be reduced.

  In the pneumatic tire of the present invention, the water drainage performance can be improved by the lateral grooves provided in the shoulder ribs. Further, since the width of the narrow groove of the lateral groove is smaller than the groove width of the lateral groove main body, the ground contact length of the land part can be extended without excessively reducing the rigidity of the land part. Similarly, since the land portion is provided with a sipe having a groove width smaller than that of the lateral groove main body, the ground contact length of the land portion can be extended without excessively reducing the rigidity of the land portion. Therefore, the deformation of the land portion due to the lateral force during turning of the vehicle can be suppressed. The lateral groove is located at the center of the shoulder rib where uneven wear is less likely to occur, and the bending point on the stepping side where uneven wear is less likely to occur is located on the shoulder side where uneven wear is less likely to occur. It is arranged on the main groove side of the rib. Therefore, the occurrence of toe-heel uneven wear before and after the lateral groove can be suppressed.

FIG. 1 is a plan view showing a pneumatic tire according to a first embodiment. The top view which shows one land part of a shoulder rib. FIG. 2C is a partially enlarged plan view of FIG. 2A. Sectional drawing of the horizontal groove main body of a horizontal groove. Sectional drawing of the narrow groove of a horizontal groove. Sectional drawing of a sipe. The top view showing the state of the middle stage of use. FIG. 4 is a plan view showing a state in a later stage of use. FIG. 9 is a plan view showing a lateral groove according to the second embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(1st Embodiment)
FIG. 1 shows a pneumatic tire (hereinafter abbreviated as “tire”) 10 according to the present embodiment. The tire 10 includes a tread portion 11 having a rib-type pattern, sidewall portions 12, 12 continuous on both sides of the tread portion 11, and a bead portion formed at a radially inner end of each sidewall portion 12 ( (Not shown)). Two or more (four in this embodiment) main grooves 13A to 13D extending in the tire circumferential direction are provided in the tread portion 11, and three or more (five in this embodiment) partitioned in the tire width direction by these. Ribs 14A to 14E are formed.

  In the tire 10 of the present embodiment, the rotation direction at the time of attachment to the vehicle and the inner and outer surfaces in the vehicle width direction are set in advance. Among the plurality of ribs 14A to 14E, the ribs 14A and 14B located at both ends in the tire width direction are adjacent to the sidewall portions 12 and 12. In FIG. 1, the shoulder rib 14A located at the right end (one end side in the tire width direction) is disposed outside in the vehicle width direction. The shoulder rib 14B located on the left side in FIG. 1 is arranged inside in the vehicle width direction.

  In the following description, the tire circumferential direction is referred to as an X direction, the tire width direction is referred to as a Y direction, and the tire radial direction is referred to as a Z direction. The direction of the arrow on the X axis may be referred to as + X direction, and the opposite direction may be referred to as -X direction. The + X direction is a preset tire rotation direction (the front side in the tire rotation direction), and the -X direction is the rear side in the tire rotation direction. The direction of the arrow on the Y axis may be referred to as + Y direction, and the opposite direction may be referred to as -Y direction. The + Y direction is a direction toward the outer end side in the preset vehicle width direction, and the -Y direction is a direction toward the inner end side in the preset vehicle width direction. The direction of the Z-axis arrow may be referred to as + Z direction, and the opposite direction may be referred to as -Z direction. The + Z direction is a direction toward the radial inside of the tire 10, and the -Z direction is a direction toward the radial outside of the tire 10.

  A plurality of lateral grooves 16 are provided on the outer shoulder rib 14A at intervals in the X direction. A plurality of land portions 17 are provided on the outer shoulder rib 14A by the lateral groove 16 so as to be partitioned in the X direction. Each land portion 17 is provided with a sipe 18 extending in the + Y direction from the main groove 13A on the −Y side.

  A plurality of lateral grooves 20 are provided on the inner shoulder rib 14B at intervals in the X direction. A plurality of land portions 21 are provided on the inner shoulder rib 14 </ b> B in the X direction by the lateral grooves 20. Each land portion 21 is provided with a lug groove 22 extending from the + Y side main groove 13B in the −Y direction.

  In the center rib 14C located at the center in the Y direction, lug grooves 24 extending from the + Y side main groove 13C toward the −Y side are provided at intervals in the X direction. On the intermediate rib 14D located between the outer shoulder rib 14A and the center rib 14C, lug grooves 26 extending from the + Y side main groove 13A toward the -Y side are provided at intervals in the X direction. . On the intermediate rib 14E located between the inner shoulder rib 14B and the center rib 14C, lug grooves 28 extending from the + Y-side main groove 13D toward the -Y side are provided at intervals in the X direction. .

  In the present embodiment, a bent portion is provided in each of the lateral groove 16 and the sipe 18 formed in the outer shoulder rib 14A. The rigidity of the land portion 17 before and after the lateral groove 16 is adjusted by the lateral groove 16 having the bent portion and the sipes 18, thereby suppressing the occurrence of uneven heel wear of the land portion 17. Note that toe-heel uneven wear refers to a state in which the kicking side of the land portion 17 located on the + X side of the lateral groove 16 is excessively worn from the stepping side of the land portion 17 located on the −X side of the lateral groove 16.

(Details of lateral groove)
As shown in FIGS. 2A and 2B, the lateral groove 16 includes a lateral groove main body 30 and a narrow groove 35, and extends from the outer end of the outer shoulder rib 14A in the Y direction to the main groove 13A. The lateral groove main body 30 extends from the + Y side end of the outer shoulder rib 14A to the −Y side toward the main groove 13A, and the narrow groove 35 extends from the −Y side end of the lateral groove main body 30 to the main groove 13A. I have. That is, one end of the narrow groove 35 communicates (opens) with the end of the lateral groove main body 30 and the other end communicates with the main groove 13A.

  The lateral groove main body 30 is formed of a slit extending linearly in a direction intersecting the main groove 13A in a direction orthogonal to the main groove 13A. Here, “intersecting in the orthogonal direction” is not limited to a strict orthogonality where the angle between the main groove 13 </ b> A and the lateral groove main body 30 is 90 degrees, but a substantially orthogonal form (for example, a range of 90 degrees ± 5 degrees). Including. Further, the expression “extending linearly” is not limited to a strict straight line extending straight, but includes a form that is substantially a straight line such as a smooth curve.

  3A, the lateral groove main body 30 includes a first front wall 31 which is a wall surface of the land portion 17 located on the + X side, and a first rear wall 32 which is a wall surface of the land portion 17 located on the −X side. And the first bottom wall 33 located on the + Z side. The first bottom wall 33 is continuous with the bottom end of the first front wall 31 located on the + Z side and the bottom end of the first rear wall 32. On the tread surface (tread surface) side of the first front wall 31, a front taper portion 31a inclined in the -X + Z direction toward the center of the first bottom wall 33 is formed. On the tread side of the first rear wall 32, a rear tapered portion 32a inclined in the + X + Z direction toward the center of the first bottom wall 33 is formed. Due to these tapered portions 31a and 32a, the groove width of the lateral groove main body 30 is gradually reduced from W1 on the tread side to W1 'on the first bottom wall 33 side. In addition, the bottom of the lateral groove main body 30 from the tapered portions 31a and 32a has a uniform groove width W1 '.

  The narrow groove 35 has a groove width W2 smaller than the groove widths W1 and W1 'of the lateral groove main body 30, and is formed to be bent (inclined) toward the -X side with respect to the horizontal groove main body 30. The groove width W2 of the narrow groove 35 is set in a range of 10% or more and 20% or less of the groove width W1 of the lateral groove main body 30. This is because if the groove width W2 is set to less than 10% of the groove width W1, the land portions 17 cannot be deformed, and all the land portions 17 of the outer shoulder ribs 14A become a single rib, so that rigidity is required. It is because it becomes higher than above. If the groove width W2 is set to be larger than 20% of the groove width W1, the -Y side of the land portion 17 is easily deformed, and the rigidity is reduced. If the narrow groove 35 is not provided and the −Y-side end of the lateral groove main body 30 is closed, the rigidity of the land portion 17 becomes excessively high and the ground contact length with the road surface cannot be secured.

The inclination angle α of the narrow groove 35 with respect to the lateral groove main body 30 is set in a range of 25 degrees or more and 35 degrees or less. This is because, if the inclination angle α is set to less than 25 degrees, there is no difference in rubber volume between the land portions 17, 17 in the front and rear directions of the lateral groove 16 in the X direction, and it becomes impossible to suppress occurrence of toe-heel uneven wear. If the inclination angle α is set wider than 35 degrees, the difference in the Y direction between the bending point Pf1 of the front walls 31 and 36 and the bending point Pb1 of the rear walls 32 and 37 becomes small, and the toe-heel uneven wear is reduced. This is because the possibility of occurrence increases.

  Referring also to FIG. 3B, the narrow groove 35 includes a second front wall 36 which is a wall surface of the land portion 17 located on the + X side, and a second rear wall 37 which is a wall surface of the land portion 17 located on the −X side. And a second bottom wall 38 located on the + Z side. The second bottom wall 38 is continuous with the bottom end of the second front wall 36 located on the + Z side and the bottom end of the second rear wall 37.

  As shown in FIG. 2B, the second rear wall 37 is substantially planar extending in the Z direction, and the tread surface side edge 32b and the bottom side edge 32c of the rear tapered portion 32a located at intervals in the Z direction. Intersects. In the following description, the intersection of the second rear wall 37 and the tread side edge 32b of the rear tapered portion 32a is referred to as a first rear bending point Pb1, and the bottom edge of the second rear wall 37 and the rear tapered portion 32a. The intersection with 32c is referred to as a second rear inflection point Pb2.

  The second front wall 36 includes a tread side edge 36a and a bottom edge 36b that branch off from a portion located on the + X side of the first rear bending point Pb1. A triangular tapered portion 36c is formed between the tread side edge 36a and the bottom side edge 36b. The tread side edge 36a crosses the tread side edge 31b of the front taper portion 31a, and the bottom side edge 36b crosses the bottom side edge 31c of the front taper portion 31a. In the following description, the intersection of the second front wall 36 and the tread side edge 31b of the front tapered portion 31a is referred to as a first front bending point Pf1, and the intersection between the second front wall 36 and the bottom edge 31c of the front tapered portion 31a. The intersection is referred to as a second front bending point Pf2.

  Here, the first front-side bending point Pf1 and the first rear-side bending point Pb1 are in contact with the road surface in the initial stage (unused state) when the use of the tire 10 is started. The second front inflection point Pf2 and the second rear inflection point Pb2 are in contact with the road surface as wear of the land portion 17 progresses due to use. Moreover, since the rigidity of the land portion 17 at the beginning of use is low, the use of the land portion 17 may cause uneven wear. On the other hand, the rigidity of the land portion 17 increases as the wear progresses through use, and the possibility of uneven wear occurring in the later stage is eliminated. However, if uneven wear occurs on the land portion 17 in the initial stage, the uneven wear state is maintained to the end even in the later stage of high rigidity.

  In the present embodiment, in order to suppress the occurrence of toe-heel uneven wear, the first front bending point Pf1 of the front walls 31 and 36 (kick-out side) where uneven wear is apt to occur is formed by changing the portion of the land portion 17 which is relatively hard to wear. Has been placed. In addition, the second rear bending points Pb1 of the rear walls 32, 37 (stepping side) where uneven wear is unlikely to occur are arranged in portions of the land portion 17 that are relatively easily worn. More specifically, the first front inflection point Pf1 is arranged on the center side in the Y direction of the outer shoulder rib 14A away from the main groove 13A, and the first rear inflection point Pb1 is located on the outer shoulder rib 14A near the main groove 13A. It is arranged on the Y side. In the Y direction of the land portion 17, the position where the first front bending point Pf1 is formed is a region where the land portion 17 is less likely to be deformed as compared with the position where the first rear bending point Pb1 is formed, and is therefore less likely to be worn. .

  As shown in FIGS. 2B, 4A, and 4B, the positions of the front bending point Pf and the rear bending point Pb in the Y direction are set so as to change as the wear of the land portion 17 progresses due to use. Specifically, the second front bending point Pf2 is disposed on the −Y side of the outer shoulder rib 14A closer to the main groove 13A than the second rear bending point Pb2, opposite to the first bending points Pf1 and Pb1. However, from the viewpoint of the entire outer shoulder rib 14A in the Y direction, the second front bending point Pf2 and the second rear bending point Pb2 are arranged at substantially the same position. Further, the second front bending point Pf2 is further away from the main groove 13A than the first front bending point Pf1, and is arranged on the center side in the Y direction of the outer shoulder rib 14A. The second rear inflection point Pb2 is located farther from the main groove 13A than the first rear inflection point Pb1, and is disposed on the center side in the Y direction of the outer shoulder rib 14A with respect to the second front inflection point Pf2.

  The second bending from the first bending points Pf1 and Pb1 by setting the Z-direction positions of the bottom side edges 31c and 32c of the tapered portions 31a and 32a, that is, the taper height H which is the dimension of the tapered portions 31a and 32a in the Z direction. The timing of changing to the points Pf2 and Pb2 can be adjusted. Specifically, the taper height H is set in a range of 10% or more and 40% or less of the groove depth D which is the dimension of the lateral groove main body 30 in the Z direction. This is because, if the taper height H is set to less than 10% of the groove depth D, the land portion 17 is worn by use and the taper portions 31a and 32a disappear, and the taper portions 31a and 32a have not yet been formed into a high rigidity region. This is because uneven wear may occur on the land portion 17 after the portions 31a and 32a disappear. This is because if the taper height H is set to be higher than 40% of the groove depth D, the period for providing the difference in rigidity of the land portion 17 becomes excessive.

  The taper width (W1−W1 ′) / 2, which is the dimension in the X direction of the tapered portions 31a and 32a, is set in a range of 30% or more and 50% or less of the entire width W1 of the lateral groove main body 30. This is because when the taper width (W1−W1 ′) / 2 is set to less than 30% of the total width W1, the first front bending point Pf1 is located on the main groove 13A side of the outer shoulder rib 14A. If the taper width (W1−W1 ′) / 2 is set to be larger than 50% of the total width W1, the groove width W1 ′ of the later-stage lateral groove main body 30 becomes excessively narrow, and the drainage performance is reduced.

(Details of sipes)
As shown in FIG. 2A, the sipe 18 extends from the + Y side of the land portion 17 toward the main groove 13 </ b> A, and extends from the −Y side end of the first sipe 42 to the main groove. And a second sipe 47. That is, the second sipe 47 has one end communicating with the end of the first sipe 42 and the other end communicating with the main groove 13A.

  The first sipe 42 and the second sipe 47 are extremely fine grooves having the same groove width W3. These groove widths W3 are set smaller than the groove width W1 of the lateral groove main body 30 and equal to or less than the groove width W2 of the narrow groove 35. The first sipe 42 extends linearly so as to intersect the main groove 13 </ b> A in a direction substantially orthogonal to the main groove 13 </ b> A, similarly to the lateral groove main body 30. Is not extended. The second sipe 47 is bent (inclined) toward the −X side with respect to the first sipe 42, similarly to the narrow groove 35. The inclination angle of the second sipe 47 with respect to the first sipe 42 is set to be the same as the inclination angle α of the narrow groove 35.

  3C, the first sipe 42 includes a first front wall 43 of the land portion 17 located on the + X side, a first rear wall 44 of the land portion 17 located on the −X side, and a + Z side. The first bottom wall 45 is defined. Similarly, the second sipe 47 includes a second front wall 48 of the land portion 17 located on the + X side, a second rear wall 49 of the land portion 17 located on the −X side, and a second bottom located on the + Z side. It is defined by a wall 50.

  In the tire 10 thus configured, the water drainage performance can be improved by the lateral groove 16 formed in the outer shoulder rib 14A. Further, since the lateral groove main body 30 is communicated with the main groove 13A through the narrow groove 35 having a groove width W2 smaller than the groove width W1 of the lateral groove main body 30, the land portion 17 does not excessively reduce the rigidity, The contact length of the portion 17 can be extended. Therefore, the deformation of the land portion 17 due to the lateral force during turning of the vehicle can be suppressed.

In the lateral groove 16, the first front bending point Pf1 of the front walls 31, 36 is arranged on the center side in the Y direction of the outer shoulder rib 14A, and the first rear bending point Pb1 of the rear walls 32, 37 is positioned on the outer shoulder rib 14A. Of the main groove 13A. Accordingly, the occurrence of toe-heel uneven wear can be suppressed while adjusting the rigidity on the front walls 31 and 36 and the rigidity on the rear walls 32 and 37 of the land portion 17 to be uniform. Therefore, the uneven wear resistance of the tire 10 can be improved .

  Moreover, the positions of the bending points Pf and Pb of the lateral groove 16 are such that uneven wear is less likely to occur after the middle stage of use shown in FIG. 4A from the early stage of use shown in FIG. By the end of use shown in FIG. 4B, the first bending point Pf1, Pb1 is changed to the second bending point Pf2, Pb2. Therefore, occurrence of toe-heel uneven wear during a period in which uneven wear may occur can be significantly suppressed. Further, the groove area of the lateral groove main body 30 decreases with the wear of the tapered portions 31a and 32a, and the contact area of the land portion 17 increases. Since the rigidity (block rigidity) of the land portion 17 is improved by increasing the ground contact area of the land portion 17, the braking distance, which is one of dry performances, can be reduced.

  The land portion 17 is formed with a bent sipe 18 having a first sipe 42 and a second sipe 47 having a groove width W3 smaller than the groove widths W1 and W1 'of the horizontal groove main body 30. Therefore, the contact length of the land portion 17 can be extended without excessively reducing the rigidity of the land portion 17. Therefore, while the rigidity of the land portion 17 is optimally adjusted, the deformation of the land portion 17 due to the lateral force during turning of the vehicle can be significantly suppressed. Also, in the sipe 18, similarly to the narrow groove 35 of the lateral groove 16, the groove width of the second sipe 47 is narrower than that of the first sipe 42, and the bending point is arranged on the center side of the land portion 17 in the Y direction. Since a difference in rigidity can be provided between the stepping-in side and the kicking-out side, uneven heel wear can be suppressed.

(2nd Embodiment)
FIG. 5 shows a lateral groove 20 formed in the outer shoulder rib 14A of the tire 10 according to the second embodiment. The lateral groove 20 differs from the first embodiment in that the second front wall 36 defining the narrow groove 35 is formed in a substantially planar shape extending in the Z direction similarly to the second rear wall 37. The second front wall 36 thus intersects the tread side edge 31b and the bottom side edge 31c of the front tapered portion 31a located at intervals in the Z direction. Of course, the tapered portion 36c shown in the first embodiment is not formed.

  According to the second embodiment, the same operation and effect as those of the first embodiment can be obtained. Moreover, in the second embodiment, since the second front wall 36 extends in a plane, the first front bending point Pf1, which is the intersection of the second front wall 36 and the tread side edge 31b of the front tapered portion 31a, Furthermore, it can be arranged at the center of the outer shoulder rib 14A in the Y direction. Therefore, occurrence of toe-heel uneven wear of the front walls 31 and 36 of the land portion 17 can be significantly suppressed.

  In addition, the pneumatic tire 10 of the present invention is not limited to the configuration of the above embodiment, and various changes are possible.

  For example, the lateral groove 16 formed in the outer shoulder rib 14A extends from the outer end to the main groove 13A with the same width W1, and the lateral groove 20 formed in the inner shoulder rib 14B has the lateral groove main body 30 and the narrow groove 35. It may be. Further, both the lateral groove 16 formed in the outer shoulder rib 14A and the lateral groove 20 formed in the inner shoulder rib 14B may be configured to have the lateral groove main body 30 and the narrow groove 35. Further, the ribs 14 </ b> C to 14 </ b> E located in the middle in the Y direction may be provided with a lateral groove similar to the lateral groove 16 having the lateral groove main body 30 and the narrow groove 35.

  In the above-described embodiment, the tapered portions 31a and 32a are formed on the first front wall 31 and the first rear wall 32 of the lateral groove 16, respectively. However, the tapered portions 31a and 32a may not be provided. In the tread portion 11, five ribs 14A to 14E are formed by forming four main grooves 13A to 13D, but the number of main grooves may be two or more.

DESCRIPTION OF SYMBOLS 10 Tire 11 Tread part 12 Side wall part 13A Main groove 13B-13D Other main grooves 14A Outer shoulder ribs 14B-14E Other ribs 16 Side groove 17 Land part 18 Sipe 20 Side groove 21 Land part 22 Lug groove 24 Lag groove 26 Lug groove 28 lug groove 30 lateral groove main body 31 first front wall 31a front taper portion 31b tread side edge 31c bottom side edge 32 first rear wall 32a rear side taper portion 32b tread side edge 32c bottom side edge 33 first bottom wall 35 narrow groove 36 Second front wall 36a Tread side edge 36b Bottom side edge 36c Taper portion 37 Second rear wall 38 Second bottom wall 42 First sipe 43 First front wall 44 First rear wall 45 First bottom wall 47 Second sipe 48 Second 2 front wall 49 second rear wall 50 second bottom wall

Claims (3)

Three or more ribs partitioned in the tire width direction by two or more main grooves extending in the tire circumferential direction,
Of the ribs, a shoulder rib located at one end side in the tire width direction is provided with a plurality of spaced apart in the tire circumferential direction, and a lateral groove extending in the tire width direction of the shoulder rib,
A sipe that is provided on a land portion of the shoulder rib that is partitioned in the tire circumferential direction by the lateral groove, and that extends in the tire width direction of the land portion.
The lateral groove is a lateral groove main body extending from the outer end of the shoulder rib in the tire width direction toward the main groove, and a narrow groove extending from the main groove side end of the lateral groove main body to the main groove. The narrow groove has a narrower groove width than the lateral groove main body , and is formed to be bent rearward in the tire rotation direction with respect to the lateral groove main body,
A first sipe extending in the tire width direction of the land portion toward the main groove; and a second sipe extending from the main groove side end of the first sipe to the main groove. The first sipe and the second sipe have a narrower groove width than the lateral groove main body, and the second sipe is formed to be bent rearward in the tire rotation direction with respect to the first sipe,
The lateral groove main body includes a first front wall located on the front side in the tire rotation direction, a first rear wall located on the rear side in the tire rotation direction, and a radially inner side of the first front wall and the first rear wall. With the first bottom wall located at
The narrow groove includes a second front wall positioned on the front side in the tire rotation direction, a second rear wall positioned on the rear side in the tire rotation direction, and the second radial direction of the second front wall and the second rear wall. It is defined by the second bottom wall located inside,
In an unused state, a first front bending point, which is an intersection between the tread surface side edge of the first front wall and the second front wall, is an intersection between the tread surface side edge of the first rear wall and the second rear wall. The pneumatic tire is located on the side of the shoulder ribs away from the main groove in the tire width direction from the first rear bending point. A front taper portion is formed on the first front wall and a rear taper portion is formed on the first rear wall so that a groove width of the lateral groove main body gradually decreases toward the first bottom wall. And
A second front bending point, which is an intersection of the bottom edge of the front taper portion located on the first bottom wall side and the second front wall, is provided on the rear taper portion located on the first bottom wall side. 2. The pneumatic tire according to claim 1, wherein the shoulder rib is located on the main groove side in the tire width direction of the shoulder rib from a second rear bending point which is an intersection of a bottom side edge and the second rear wall. 3. .   The second front wall has a triangular tapered portion at an end on the first front wall side,
  The first front bending point is an intersection of a tread side edge of the tapered portion and the tread side edge of the first front wall,
  The pneumatic tire according to claim 2, wherein the second front bending point is an intersection of a bottom edge of the tapered portion and the bottom edge of the front tapered portion.

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