JP2017140858A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of restraining an increase in residual cornering force when the tire is worn.SOLUTION: A plurality of lug grooves 41 and a plurality of sipes 43 are arranged in a land part row 40 of at least one row. When determining the total sum of the projection length of the lug groove resulting from projecting each one of the lug grooves and sipes in the direction of the reference axis which forms an angle θ relative to the tire circumferential direction and the total sum of the projection length of the sipes in a range of 0°≤θ≤180° for each land part row in a grounding area of a tread part 1, the following relational expressions (1)-(3) are simultaneously satisfied: |θ1-θ2|≤10°...(1)|θ1'-θ2'|≥90°...(2)|θ1-θ1'|≤10°...(3)θ1: an angle at which the total sum of the projection length of the lug groove is maximized when the tire is new, θ2: an angle at which the total sum of the projection length of the sipe is maximized when the tire is new, θ1': an angle at which the total sum of the projection length of the lug groove is maximized at a sipe bottom position, and θ2': an angle at which the total sum of the projection length of the sipe is maximized at the sipe bottom position.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pneumatic tire in which a plurality of lug grooves extending while inclining with respect to the tire width direction are formed in at least one land portion row of a tread portion, and more specifically, residual cornering during wear The present invention relates to a pneumatic tire that can suppress an increase in force.

  In pneumatic tires including passenger car tires, a plurality of circumferential grooves extending in the tire circumferential direction are formed in the tread portion, and a plurality of land portion rows are partitioned by the circumferential grooves. In addition, a plurality of lug grooves extending in the tire width direction are formed in the land portion row. The extending direction of such a lug groove is not parallel to the tire width direction and is often inclined with respect to the tire width direction.

  However, when the tread portion of the pneumatic tire described above is worn, there is a problem that the shear rigidity in the tire circumferential direction of the tread portion is increased and the residual cornering force due to the inclined lug groove is increased. When the residual cornering force increases, the vehicle flow becomes obvious, and the straightness of the vehicle may be impaired.

  In order to suppress such an increase in residual cornering force, a part of the lug groove inclined at the time of wear is worn away by providing a bottom raised portion in a part of the longitudinal direction of the lug groove inclined with respect to the tire width direction. Has been proposed (see, for example, Patent Document 1). However, in this case, a part of the lug groove is worn during wear, so that the wet performance during wear changes significantly.

  In addition, as another method for suppressing an increase in the residual cornering force, by adopting a structure in which the groove wall angle of the lug groove with respect to the normal direction of the tread surface is changed along the longitudinal direction, the wear is reduced. It has been proposed to gradually reduce the inclination angle of the lug groove with respect to the tire width direction as it progresses (see, for example, Patent Document 2). However, in the lug groove in which the groove wall angle is changed along the longitudinal direction, the groove width decreases as the tread portion wears, so that the wet performance is not only deteriorated, but the block defined by the lug groove is twisted. Due to the structure, uneven wear tends to occur. Therefore, this method is not the best policy.

JP, 2015-120428, A JP 2011-63079 A

  An object of the present invention is to suppress an increase in residual cornering force during wear when providing a plurality of lug grooves extending while inclining with respect to the tire width direction in at least one land portion row of a tread portion. It is to provide a pneumatic tire that enables the above.

In order to achieve the above object, the pneumatic tire of the present invention has a plurality of circumferential grooves formed in the tread portion extending in the tire circumferential direction, and a plurality of rows partitioned by the circumferential groove in the tread portion. In pneumatic tires with land rows formed,
At least one land portion row of the plurality of land portion rows, a plurality of lug grooves extending while inclining with respect to the tire width direction, and extending in the tire width direction, A plurality of sipes having different inclination angles with respect to the tire width direction and different inclination angles with respect to the tire width direction at the bottom position are disposed, and each of the lug grooves and the sipes is angle θ with respect to the tire circumferential direction. The sum of the projection lengths of the lug grooves and the sum of the projection lengths of the sipe obtained by projecting in the direction of the reference axis forming 0 ° ≦ θ ≦ for each land portion row in the contact area of the tread portion A land portion row that satisfies the following relational expressions (1) to (3) at the same time is obtained when it is obtained within a range of 180 °.
| Θ1-θ2 | ≦ 10 ° (1)
| Θ1′−θ2 ′ | ≧ 90 ° (2)
| Θ1-θ1 ′ | ≦ 10 ° (3)
Here, θ1: angle at which the total sum of projection lengths of lug grooves when new is new, θ2: angle at which the sum of projection lengths of sipes is maximum when new, θ1 ′: projection length of lug grooves at the sipe bottom position The angle at which the total sum is the maximum, θ2 ′: the angle at which the total sum of the projected lengths of the sipe is the maximum at the sipe bottom position.

  In the present invention, a plurality of lug grooves extending while inclining with respect to the tire width direction in at least one land portion row, and an inclination angle with respect to the tire width direction on the tread surface extending in the tire width direction And a plurality of sipes having different inclination angles with respect to the tire width direction at the bottom position are combined and arranged to form a land portion row that satisfies the above relational expressions (1) to (3) at the same time. As the tire travels, the inclination angle of the sipe with respect to the tire width direction gradually changes, and an increase in residual cornering force during wear can be suppressed. As a result, the vehicle flow can be prevented and the straight traveling performance of the vehicle can be improved. Further, when the above structure is adopted, there is no inconvenience that wet performance and uneven wear resistance are deteriorated during wear.

  In this invention, it is preferable that the land part row | line | column which satisfy | fills the said relational expressions (1)-(3) simultaneously is a shoulder land part row | line | column. Since the shoulder land portion row contributes greatly to the residual cornering force, the shoulder land portion row satisfies the relational expressions (1) to (3) at the same time, thereby effectively suppressing an increase in the residual cornering force during wear. be able to.

  Moreover, it is preferable that the maximum depth of a sipe is 80% or more of the maximum depth of a lug groove. By sufficiently securing the maximum depth of the sipe with respect to the maximum depth of the lug groove, it is possible to fully enjoy the effect of correcting the residual cornering force until the wear life is reached.

  Furthermore, it is preferable that the sipe has a larger groove width at the bottom side portion than at the tread surface side portion. Since the rigidity of the tread tends to increase with the progress of wear, the groove width of the bottom part of the sipe is relatively increased to reduce the rigidity of the tread during wear and the residual cornering force. Can be suppressed.

 In the present invention, the sipe is a narrow groove having a groove width of 1.5 mm or less, and the lug groove is a groove having a groove width of 2 mm to 15 mm. In addition, the contact area of the tread is based on the contact width in the tire axial direction measured when a normal load is applied by placing the tire on a normal rim and filling it with normal internal pressure, and placing it vertically on a flat surface. This area is specified by The “regular rim” is a rim determined for each tire in the standard system including the standard on which the tire is based. For example, a standard rim for JATMA, “Design Rim” for TRA, or ETRTO. Then, “Measuring Rim” is set. “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. The maximum air pressure is for JATA and the table “TIRE ROAD LIMITS AT VARIOUS” is for TRA. The maximum value described in “COLD INFRATION PRESURES”, “INFLATION PRESURE” for ETRTO, but 180 kPa when the tire is a passenger car. “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. The maximum load capacity is JATMA, and the table “TIRE ROAD LIMITS AT VARIOUS” is TRA. The maximum value described in “COLD INFORATION PRESSURES” is “LOAD CAPACITY” if it is ETRTO, but if the tire is a passenger car, the load is equivalent to 88% of the load.

It is meridian sectional drawing which shows the pneumatic tire which consists of embodiment of this invention. FIG. 2 is a development view showing a tread pattern (when new) of the pneumatic tire of FIG. 1. FIG. 2 is a development view showing a tread pattern (when worn) of the pneumatic tire of FIG. 1. It is a top view which shows the block of the shoulder land part row | line | column in the tread pattern of FIG. It is a side view which shows the block of the shoulder land part row | line | column in the tread pattern of FIG. It is a graph which shows the relationship between angle (theta) of a reference axis, the sum total of the projection length of a lug groove, and the sum total of the projection length of a sipe. The block of a shoulder land part row | line | column is shown, (a) is a top view which shows the state at the time of a new article, (b) is a top view which shows the state of middle wear, (c) is a plane which shows the state of late wear FIG. The various sipes which enlarged the groove width of the bottom side part are shown, (a)-(c) is a sectional view of each sipes.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. 1 to 5 show a pneumatic tire according to an embodiment of the present invention.

  As shown in FIG. 1, the pneumatic tire of the present embodiment includes a tread portion 1 that extends in the tire circumferential direction and has an annular shape, and a pair of sidewall portions 2, 2 disposed on both sides of the tread portion 1. And a pair of bead portions 3 and 3 disposed inside the sidewall portion 2 in the tire radial direction.

  A carcass layer 4 is mounted between the pair of bead portions 3 and 3. The carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction, and is folded from the inside of the tire to the outside around the bead core 5 disposed in each bead portion 3. A bead filler 6 made of a rubber composition having a triangular cross-section is disposed on the outer periphery of the bead core 5.

  On the other hand, a plurality of belt layers 7 are embedded on the outer peripheral side of the carcass layer 4 in the tread portion 1. These belt layers 7 include a plurality of reinforcing cords inclined with respect to the tire circumferential direction, and are arranged so that the reinforcing cords cross each other between the layers. In the belt layer 7, the inclination angle of the reinforcing cord with respect to the tire circumferential direction is set in a range of, for example, 10 ° to 40 °. A steel cord is preferably used as the reinforcing cord of the belt layer 7. For the purpose of improving high-speed durability, at least one belt cover layer 8 in which reinforcing cords are arranged at an angle of, for example, 5 ° or less with respect to the tire circumferential direction is disposed on the outer peripheral side of the belt layer 7. Yes. As the reinforcing cord of the belt cover layer 8, an organic fiber cord such as nylon or aramid is preferably used.

  In addition, although the tire internal structure mentioned above shows the typical example in a pneumatic tire, it is not limited to this.

  As shown in FIG. 2, the tread portion 1 is formed with four circumferential grooves 11 extending in the tire circumferential direction. By these four circumferential grooves 11, the tread portion 1 has a center land portion row 20 located on the tire equator CL and a pair of intermediate land portions row located on the outer side in the tire width direction than the center land portion row 20. 30 and a shoulder land portion row 40 located on the outer side in the tire width direction from the intermediate land portion row 30 are partitioned. In FIG. 2, TCW is a grounding width of the tread portion 1, and a region within the grounding width TCW is a grounding region.

  The center land portion row 20 is formed with a plurality of lug grooves 21 extending while inclining with respect to the tire width direction and a plurality of sipes 23 extending with inclination with respect to the tire width direction. Yes. One end of the lug groove 21 opens into the circumferential groove 11, and the other end terminates in the center land portion row 20. The lug grooves 21 include one that opens to one side in the tire width direction and one that opens to the other side in the tire width direction, and the lug grooves 21 having different opening directions are alternately arranged along the tire circumferential direction. The sipe 23 is disposed so as to extend from the end of the lug groove 21 to the circumferential groove 11 on the opposite side.

  The intermediate land portion row 30 includes a plurality of lug grooves 31 and 32 extending while inclining with respect to the tire width direction, a plurality of sipes 33 extending while inclining with respect to the tire width direction, and a tire. A plurality of sipes 34 extending along the circumferential direction are formed. One end of the lug groove 31 opens into the circumferential groove 11 on the outer side in the tire width direction, and the other end terminates in the intermediate land portion row 30. The lug grooves 32 cross the intermediate land portion row 30, and the inner portion in the tire width direction is thicker than the outer portion in the tire width direction. The lug grooves 31 and the lug grooves 32 are alternately arranged along the tire circumferential direction. Further, the sipe 33 is disposed so as to extend from the end of the lug groove 31 to the circumferential groove 11 on the opposite side. The sipe 34 is disposed so as to connect the lug groove 31 and the lug groove 32 at the central portion of the intermediate land portion row 30.

  The shoulder land portion row 40 includes a plurality of lug grooves 41 extending while inclining with respect to the tire width direction, and a plurality of sipes 43 extending while inclining with respect to the tire width direction at least on the tread surface. Is formed. The lug groove 41 crosses the shoulder land portion row 40. Further, one end of the sipe 43 opens in the circumferential groove 11 on the inner side in the tire width direction, and the other end terminates in the shoulder land portion row 40. These lug grooves 41 and sipes 43 are alternately arranged along the tire circumferential direction.

  As shown in FIGS. 4 and 5, the sipe 43 disposed in the shoulder land portion row 40 has a different inclination angle with respect to the tire width direction at the tread surface P1 and an inclination angle with respect to the tire width direction at the bottom position P2. ing. That is, the sipe 43 has a structure twisted along the depth direction so that the contour line L1 on the tread surface P1 and the contour line L2 on the bottom position P2 intersect each other.

In the pneumatic tire, with respect to the shoulder land portion row 40, the projection length of the lug groove 41 obtained by projecting each of the lug groove 41 and the sipe 43 in the direction of the reference axis that forms an angle θ with respect to the tire circumferential direction. And the sum of the projection lengths of the sipe 43 in the contact area of the tread portion 1 within a range of 0 ° ≦ θ ≦ 180 °, the shoulder land portion row 40 has the following relational expressions (1) to (3 ) At the same time.
| Θ1-θ2 | ≦ 10 ° (1)
| Θ1′−θ2 ′ | ≧ 90 ° (2)
| Θ1-θ1 ′ | ≦ 10 ° (3)
Here, θ1: angle at which the total sum of projection lengths of lug grooves when new is new, θ2: angle at which the sum of projection lengths of sipes is maximum when new, θ1 ′: projection length of lug grooves at the sipe bottom position The angle at which the total sum is the maximum, θ2 ′: the angle at which the total sum of the projected lengths of the sipe is the maximum at the sipe bottom position.

  FIG. 6 is a graph showing the relationship between the angle θ of the reference axis and the total projection length of the lug grooves 41 and the total projection length of the sipe 43. In FIG. 6, the distance from the center point O to the outer side in the radial direction indicates the total projection length. The broken line indicates the total projection length of the lug groove 41 on the tread surface when new and the total projection length of the lug groove 41 at the sipe bottom position, and the solid line indicates the projection length of the sipe 43 on the tread surface when new. The one-dot chain line indicates the total projection length of the sipe 43 at the sipe bottom position.

  In FIG. 6, the total projection length of the lug groove 41 on the tread surface when new (a broken line) and the total projection length of the lug groove 41 at the sipe bottom position (broken line) as the angle θ of the reference axis changes. Gradually changes, and the angle θ1 at which the total sum of the projection lengths of the lug grooves 41 becomes the maximum and the angle θ1 ′ at which the total sum of the projection lengths of the lug grooves 41 at the sipe bottom position becomes 34.5. °. On the other hand, as the angle θ of the reference axis changes, the total projected length of the sipe 43 on the tread surface when new (solid line) and the total projected length of the sipe 43 at the sipe bottom position (dashed line) gradually increase. The angle θ2 at which the total sum of the projected lengths of the sipe 43 changes to 32 ° when it is new is 32 °, and the angle θ2 ′ at which the sum of the projected lengths of the sipe 43 is maximum at the sipe bottom position is 147.5 °. ing. That is, the value of | θ1-θ2 | is 2.5 °, the value of | θ1′−θ2 ′ | is 113 °, and the value of | θ1-θ1 ′ | is 0 °.

  In the pneumatic tire described above, the shoulder land portion row 40 has a plurality of lug grooves 41 extending while inclining with respect to the tire width direction and the tire land direction 40 with respect to the tire width direction on the tread surface extending in the tire width direction. A plurality of sipes 43 having different inclination angles and inclination angles with respect to the tire width direction at the bottom position are arranged in combination, and the shoulder land portion row 40 satisfies the above relational expressions (1) to (3) at the same time. Thus, as the wear progresses, the inclination angle of the sipe 43 with respect to the tire width direction gradually changes, and acts to suppress an increase in residual cornering force during wear.

  FIGS. 7A to 7C show state changes accompanying wear of the shoulder land row. As shown in FIG. 7A, when new, the lug groove 41 and the sipe 43 are inclined in the same direction with respect to the tire width direction. On the other hand, as shown in FIG. 7B, the lug groove 41 is not changed in the middle stage of wear, but the sipe 43 is substantially parallel to the tire width direction. Further, as shown in FIG. 7C, the lug groove 41 is not changed in the late wear state, but the sipe 43 is inclined in the direction opposite to the lug groove 41. In other words, the tread pattern of FIG. 2 becomes as shown in FIG. 3 as wear progresses. Therefore, although the residual cornering force due to the lug groove 41 increases as the wear of the tread portion 1 progresses, the sipe 43 acts to cancel the residual cornering force due to the lug groove 41. As a result, the vehicle flow can be prevented and the straight traveling performance of the vehicle can be improved. Further, when the above structure is adopted, there is no inconvenience that wet performance and uneven wear resistance are deteriorated during wear.

  In particular, in the pneumatic tire described above, the shoulder land portion row 40 having a great influence on the residual cornering force satisfies the relational expressions (1) to (3) at the same time, so that it is effective to increase the residual cornering force during wear. Can be suppressed.

  In the pneumatic tire described above, it is necessary to satisfy the relationship of | θ1−θ2 | ≦ 10 °. However, when the tire is new, the lug groove 41 and the sipe 43 are inclined in the same direction with respect to the tire width direction. This ensures a residual cornering force when new. If the value of | θ1−θ2 | is too large, it is difficult to ensure the remaining cornering force when new. In order to secure a residual cornering force at the time of a new article, it is preferable to satisfy a relationship of 0 ° <θ1 ≦ 45 °, more preferably a relationship of 10 ° <θ1 ≦ 30 °.

  Further, in the above pneumatic tire, it is necessary to satisfy the relationship of | θ1′−θ2 ′ | ≧ 90 °, but this causes the lug groove 41 and the sipe 43 to be reversed with respect to the tire width direction during wear. The increase in residual cornering force during wear can be suppressed by inclining in the direction. If the value of | θ1′−θ2 ′ | is too small, the effect of suppressing an increase in residual cornering force during wear becomes insufficient. When θ1 ′ <45 °, the relationship 90 ° <| θ1′−θ2 ′ | <180 ° −2 × θ1 ′ may be satisfied.

  Furthermore, in the above pneumatic tire, it is necessary to satisfy the relationship of | θ1−θ1 ′ | ≦ 10 °. This makes it possible to minimize the change in the angle of the lug groove 41 with the progress of wear. , To ensure that there is no substantial twist in the groove wall of the lug groove 41. As a result, it is possible to avoid the inconvenience that the wet performance and uneven wear resistance are reduced during wear. If the value of | θ1−θ1 ′ | is too large, wet performance and uneven wear resistance may be deteriorated during wear. In particular, the relationship | θ1-θ1 ′ | ≦ 3 ° should be satisfied.

  As shown in FIG. 5, the maximum depth d of the sipe 43 is 80% or more of the maximum depth D of the lug groove 41, and more preferably 90% to 100% of the maximum depth D of the lug groove 41. . By sufficiently securing the maximum depth d of the sipe 43 with respect to the maximum depth D of the lug groove 41, it is possible to fully enjoy the effect of correcting the residual cornering force until the wear life is reached. If the maximum depth d of the sipe 43 is too small, the sipe 43 disappears early with respect to the lug groove 41, so that the effect of correcting the residual cornering force in the later stage of wear cannot be obtained.

  FIGS. 8A to 8C show various sipes in which the groove width of the bottom portion is increased. As the sipe 43, it is possible to adopt a sipe 43 having a certain groove width. However, as shown in FIGS. 8A to 8C, the sipe 43 has a lower portion than the groove width of the tread side portion. A structure with a relatively large groove width may be employed. 8A, the groove width of the sipe 43 is gradually increased toward the bottom side. In FIG. 8B, the bottom side portion of the sipe 43 is swollen more than the tread side portion, and the cross-sectional shape thereof is spherical. In FIG. 8C, the groove width of the sipe 43 gradually increases toward the bottom. When such a structure is adopted, the rigidity of the tread portion 1 increases as the wear progresses. However, since the groove width of the sipe 43 increases as the wear progresses, the rigidity of the tread portion 1 during wear is reduced. Can be reduced. This is effective in suppressing an increase in residual cornering force.

  In the above-described embodiment, the case where the land portion row that simultaneously satisfies the relational expressions (1) to (3) is the shoulder land portion row 40 has been described. However, in the present invention, a plurality of rows of land portions divided into tread portions. The inclined lug groove and the twisted sipe may be formed in at least one land portion row of the row, and the land portion row may satisfy the relational expressions (1) to (3) at the same time. By providing the land portion row having such a configuration, it is possible to suppress an increase in residual cornering force during wear.

  A pneumatic tire having a tire size of 195 / 65R15 91H, in which a plurality of circumferential grooves extending in the tire circumferential direction are formed in the tread portion, and a plurality of land portion rows partitioned by the circumferential grooves are formed in the tread portion. In the tire, a tread pattern as shown in FIG. 2 is formed, a sipe having a twisted structure is applied to a specific land portion row, and each of the lug groove and the sipe has a direction of a reference axis that forms an angle θ with respect to the tire circumferential direction. When the total sum of the projection lengths of the lug grooves and the total projection length of the sipe obtained by projecting onto the ground region of the tread portion is determined in the range of 0 ° ≦ θ ≦ 180 ° for each land portion row, Angle θ1 that maximizes the total projection length of the lug groove when new, angle θ2 that maximizes the total projection length of sipe when new, and angle that maximizes the total projection length of the lug groove at the sipe bottom position θ1 'at the sipe bottom Comparative Example 1 in which the values of | θ1−θ2 |, | θ1′−θ2 ′ |, and | θ1−θ1 ′ | obtained from the angle θ2 ′ that maximizes the total projected length of the -2 and Examples 1-7 tires were produced.

  In Comparative Examples 1-2 and Examples 1-7, the maximum depth of the lug groove, the maximum depth of the sipe, and the thickness of the sipe are as shown in Table 1. For comparison, a conventional tire having the same structure as in Example 1 was prepared except that the sipe was formed in a planar shape instead of a twisted structure.

  These test tires were evaluated for residual cornering force (residual CF) and wet performance by the following test methods, and the results are also shown in Table 1.

Residual cornering force:
Remaining cornering force (N) under the condition that each test tire is assembled to a wheel of rim size 15 × 6J, the air pressure is 200 kPa, and the load corresponding to 80% of the maximum load capacity specified in JATMA (2015 version) is applied. Was measured. Such measurement was performed when the test tire was new, 50% worn, and 80% worn.

Wet performance:
Each test tire was assembled on a wheel with a rim size of 15 × 6J and mounted on a test vehicle. The air pressure was 200 kPa, and the lap time was measured under the same wet conditions on a test course consisting of a paved road. Such measurement was performed when the test tire was new, 50% worn, and 80% worn. The evaluation results are shown as indices using the reciprocals of the measured values, each of which is 100 as a conventional example when new, 50% worn, and 80% worn. The larger the index value, the better the wet performance.

  As can be seen from Table 1, the tires of Examples 1 to 7 had reduced residual cornering force and good wet performance in comparison with the conventional example. On the other hand, since the tire of Comparative Example 1 has a value of | θ1′−θ2 ′ | that is too small, the effect of suppressing an increase in residual cornering force during wear is insufficient. In the tire of Comparative Example 2, the value of | θ1−θ1 ′ | was too large, so that the wet performance was deteriorated during wear.

DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 3 Bead part 11 Circumferential groove 20, 30, 40 Land part row | line | column 21, 31, 32, 41 Lug groove 23, 33, 34, 43 Sipe

Claims (4)

In a pneumatic tire in which a plurality of circumferential grooves extending in the tire circumferential direction are formed in the tread portion, and a plurality of land portion rows partitioned by the circumferential groove are formed in the tread portion,
At least one land portion row of the plurality of land portion rows, a plurality of lug grooves extending while inclining with respect to the tire width direction, and extending in the tire width direction, A plurality of sipes having different inclination angles with respect to the tire width direction and different inclination angles with respect to the tire width direction at the bottom position are disposed, and each of the lug grooves and the sipes is angle θ with respect to the tire circumferential direction. The sum of the projection lengths of the lug grooves and the sum of the projection lengths of the sipe obtained by projecting in the direction of the reference axis forming 0 ° ≦ θ ≦ for each land portion row in the contact area of the tread portion A pneumatic tire characterized by constituting a land portion row that simultaneously satisfies the following relational expressions (1) to (3) when determined in a range of 180 °.
| Θ1-θ2 | ≦ 10 ° (1)
| Θ1′−θ2 ′ | ≧ 90 ° (2)
| Θ1-θ1 ′ | ≦ 10 ° (3)
Here, θ1: angle at which the total sum of projection lengths of lug grooves when new is new, θ2: angle at which the sum of projection lengths of sipes is maximum when new, θ1 ′: projection length of lug grooves at the sipe bottom position The angle at which the total sum is the maximum, θ2 ′: the angle at which the total sum of the projected lengths of the sipe is the maximum at the sipe bottom position.   2. The pneumatic tire according to claim 1, wherein the land portion row that simultaneously satisfies the relational expressions (1) to (3) is a shoulder land portion row.   The pneumatic tire according to claim 1 or 2, wherein the maximum depth of the sipe is 80% or more of the maximum depth of the lug groove.   The pneumatic tire according to any one of claims 1 to 3, wherein the sipe has a groove width at the bottom portion larger than a groove width at the tread surface portion.

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