JP2010042765A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire reducing rolling resistance while inhibiting deterioration of maneuvering stability. <P>SOLUTION: In the pneumatic tire in which several circumferential grooves 1-3 extending in the circumferential direction of the tire are arranged in a tread part T and plural rows of land parts 10-30 are divided by the circumferential grooves 1-3, a plurality of sipes 33 extending in the tire width direction are arranged in at least one row of the land part, the sipes 33 are made into a 3-dimensional structure in which the sipe includes a portion of a jigzag shape or a wave shape in the tread surface and diverges substantially linearly in the bottom, and the extending direction in the tread surface and the extending direction in the bottom of the sipes 33 are arranged crosswise respective to each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pneumatic tire that is effective in reducing the load on the environment, and more particularly to a pneumatic tire that can reduce rolling resistance while suppressing a decrease in steering stability.

  In recent years, in pneumatic tires, there has been a demand for a reduction in environmental load, and in particular, there has been a demand for further reduction in rolling resistance at a constant speed. Usually, when rolling resistance is reduced, a technique using a tread rubber having a low hysteresis loss is employed. However, in such a technique, the gripping force is lowered, and thus the steering stability tends to be lowered.

  On the other hand, by forming a sipe along the longitudinal direction of the lug groove at the bottom of the lug groove extending in the tire width direction in the tread portion, the tensile deformation of the tread rubber is suppressed, thereby reducing rolling resistance. It has been proposed (see, for example, Patent Document 1).

However, when a sipe is formed at the bottom of the lug groove, the land portion is divided in the tire circumferential direction, so that the ability to support lateral input is reduced, which causes a reduction in steering stability. Therefore, it is difficult to achieve both maintenance of steering stability and reduction of rolling resistance.
JP 2007-1359 A

  An object of the present invention is to provide a pneumatic tire that can reduce rolling resistance while suppressing a decrease in steering stability.

  The pneumatic tire of the present invention for achieving the above object is a pneumatic tire in which a plurality of circumferential grooves extending in the tire circumferential direction are provided in a tread portion, and a plurality of rows of land portions are partitioned by the circumferential grooves. A plurality of sipes extending in the tire width direction are provided in at least one row of land portions, and these sipes have a three-dimensional structure that includes a zigzag or wavy portion on the tread surface and converges substantially linearly at the bottom, and The extending direction at the tread surface of the sipe and the extending direction at the bottom part intersect each other.

  In another pneumatic tire of the present invention for achieving the above object, a plurality of circumferential grooves extending in the tire circumferential direction are provided in a tread portion, and a plurality of rows of land portions are partitioned by the circumferential grooves. In a tire, a plurality of compound grooves formed by connecting lug grooves extending in the tire width direction and sipes are provided in at least one row of land portions, and the sipes include a zigzag or wavy portion on the tread surface. Then, the three-dimensional structure converges substantially linearly, and the extending direction on the tread surface of the sipe and the extending direction on the bottom part intersect each other.

  In the present invention, since the sipe has a three-dimensional structure that includes a zigzag or wavy portion on the tread surface and converges substantially linearly at the bottom, the tread at the time of stepping and kicking when the tire rolls Because the sipe opens from the bottom and allows fine bending of the land with respect to the change in curvature of the tire in the tire circumferential direction, it suppresses the tensile deformation in the tire circumferential direction of the tread rubber, thereby reducing the rolling resistance be able to. In addition, the sipe includes a zigzag or wavy portion on the tread surface, and the extension direction on the tread surface of the sipe and the extension direction on the bottom intersect each other, so that the sipe has a It is possible to suppress the falling of the part and to ensure sufficient steering stability.

  In the present invention, the sipe having the above three-dimensional structure may be provided alone with respect to the land portion, or may be provided as a composite groove formed by connecting a lug groove and a sipe.

  When the sipe having the three-dimensional structure is provided independently for the land portion, it is desirable to adopt the following configuration. That is, the sipe is arranged on the shoulder land portion located on the outermost side in the tire width direction, and one end of the sipe is communicated with the inner circumferential groove in the shoulder land portion, while the other end is extended to the outside of the ground contact end. Is preferred. By disposing the sipe in the shoulder land portion where the change in curvature of the tread portion at the time of tire rolling is the largest, the rolling resistance can be effectively reduced. Further, it is preferable that the sipe is disposed in an intermediate land portion located inside the shoulder land portion, and the both ends of the sipe communicate with the circumferential grooves on both sides in the intermediate land portion. Thereby, a deformation | transformation of a shoulder land part can be accelerated | stimulated and the reduction effect of rolling resistance can be heightened. Furthermore, the sipe is preferably disposed at least on the shoulder land portion inside the vehicle when the vehicle is mounted. Normally, a negative camber is set in the vehicle, and the contribution to the rolling resistance of the shoulder land portion inside the vehicle is large. Therefore, the effect of reducing rolling resistance can be enhanced by arranging the sipe in that portion.

  The length W1 in the tire width direction on the tread surface of the zigzag or corrugated portion with respect to the length W0 in the tire width direction on the sipe tread surface has a relationship of W1 / W0 = 0.40-0.80. It is preferable to do. As a result, it is possible to ensure sufficient steering stability and prevent block chipping.

  The sipe is formed in a zigzag shape formed by repeating a first segment located on the tire width direction center side on the tread surface and a second segment located on the outer side in the tire width direction, and the tire circumferential direction of the first segment and the second segment. It is preferable that the inclination angle of the first segment is set in the range of 30 ° to 70 ° and the inclination angle of the second segment is set in the range of −30 ° to 10 °. In this case, the first segment having a relatively large inclination angle with respect to the tire circumferential direction suppresses the tensile deformation of the tread rubber so that the sipe can be easily opened, while the second segment has a relatively small inclination angle with respect to the tire circumferential direction. It is possible to effectively support lateral input, and it is possible to suppress a decrease in steering stability.

  The depth of the sipe at a position communicating with at least the circumferential groove is preferably set in a range of 70% to 100% of the maximum depth of the circumferential groove. This makes it possible to maximize the rolling resistance reduction effect.

  The extension direction at the bottom of the sipe is set in a range of 80 ° to 100 ° with respect to the tire circumferential direction, and the extension direction at the tread surface of the sipe is 20 ° to 50 ° with respect to the extension direction at the bottom of the sipe. It is preferable to set in the range. This makes it possible to maximize the rolling resistance reduction effect.

  On the other hand, when the sipe having the above three-dimensional structure is provided as a composite groove formed by connecting a lug groove and a sipe to the land portion, it is desirable to adopt the following configuration. That is, the composite groove is disposed in the shoulder land portion located on the outermost side in the tire width direction, and the end on the sipe side of the composite groove is communicated with the inner circumferential groove in the shoulder land portion, while the end on the lug groove side. It is preferable to extend the portion to the outside of the ground end. By disposing the composite groove in the shoulder land portion where the curvature change of the tread portion during tire rolling is greatest, the rolling resistance can be effectively reduced. Preferably, the composite groove is disposed in an intermediate land portion located inside the shoulder land portion, and both ends of the composite groove are communicated with the circumferential grooves on both sides in the intermediate land portion. Thereby, a deformation | transformation of a shoulder land part can be accelerated | stimulated and the reduction effect of rolling resistance can be heightened. Furthermore, it is preferable that the composite groove is disposed at least on the shoulder land portion inside the vehicle when the vehicle is mounted. Usually, a negative camber is set in a vehicle, and the contribution to the rolling resistance of the shoulder land portion inside the vehicle is large. Therefore, the effect of reducing rolling resistance can be enhanced by arranging the composite groove in that portion. .

  The length W11 in the tire width direction in the ground contact region of the lug groove is in the relationship of W11 / W10 = 0.40-0.80 with respect to the length W10 in the tire width direction in the ground contact region of the shoulder land portion. It is preferable. Thereby, while ensuring steering stability, drainage can be ensured.

  The sipe is formed in a zigzag shape in which a first segment located on the tire width direction center side and a second segment located on the outer side in the tire width direction are repeated on the tread surface, and the tire circumferential direction of these first segment and second segment It is preferable that the inclination angle of the first segment is set in a range of 30 ° to 70 ° and the inclination angle of the second segment is set in a range of −30 ° to 10 °. In this case, the first segment having a relatively large inclination angle with respect to the tire circumferential direction suppresses the tensile deformation of the tread rubber so that the sipe can be easily opened, while the second segment has a relatively small inclination angle with respect to the tire circumferential direction. It is possible to effectively support lateral input, and it is possible to suppress a decrease in steering stability.

  The depth of the sipe is preferably set in the range of 80% to 100% of the maximum depth of the lug groove connected to it. This makes it possible to maximize the rolling resistance reduction effect.

  The extension direction at the bottom of the sipe is set in a range of 80 ° to 100 ° with respect to the tire circumferential direction, and the extension direction at the tread surface of the sipe is set to 20 ° to 50 ° with respect to the extension direction at the bottom of the sipe. It is preferable to set in the range. This makes it possible to maximize the rolling resistance reduction effect.

  In the present invention, the contact area is filled with air pressure (maximum air pressure) corresponding to the maximum load capacity defined for each tire in the standards (JATMA, TRA, ETRTO) on which the tire is based. This is a grounding region when a load of 80% of the maximum load capacity is applied on a plane so as to be grounded. The ground contact end is an outer end of the ground contact region in the tire axial direction.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a developed view showing one side of a tread pattern of a pneumatic tire according to an embodiment of the present invention, with a tire equator line CL as a boundary. FIG. 2 is an enlarged view showing the sipe of FIG.

  As shown in FIG. 1, a plurality of circumferential grooves 1 to 3 extending in the tire circumferential direction are formed in the tread portion T, and a plurality of rows of land portions 10, 20, and 30 are defined by the circumferential grooves 1 to 3. Has been. More specifically, the center land portion 10 closest to the tire equator line CL, the intermediate land portion 20 located outside the center land portion 10, and the shoulder land portion 30 located outside the intermediate land portion 20 is there. Note that the circumferential groove 1 located on the tire equator line CL and the circumferential groove 3 located on the most shoulder side correspond to main grooves having a groove width of 3 mm to 25 mm and a groove depth of 7 mm to 13 mm. is there.

  A plurality of lug grooves 11 extending in the tire width direction are formed in the center land portion 10, and a plurality of blocks 12 are divided by the lug grooves 11. A raised portion 11 a is formed at the center side portion of the lug groove 11. Further, a chamfered portion 12 a is formed at an acute corner portion of the block 12.

  A plurality of lug grooves 21 extending in the tire width direction are formed in the intermediate land portion 20, and a plurality of blocks 22 are partitioned by these lug grooves 21. The lug groove 21 is disposed on an extension line of the lug groove 11.

  A plurality of lug grooves 31 extending in the tire width direction are formed in the shoulder land portion 30. These lug grooves 31 extend from the inner side to the outer side of the ground contact end E, the inner end portion is not in communication with the circumferential groove 3, and the outer end portion is bent in the tire circumferential direction. The shoulder land portion 30 is formed with a plurality of sipes 33 extending in the tire width direction. One end of each sipe 33 communicates with the inner circumferential groove 3 and the other end extends to the outside of the ground end E. The sipe 33 has a three-dimensional structure that includes a zigzag or wavy portion on the tread surface and converges substantially linearly at the bottom (see FIG. 2). In addition, the extending direction of the sipe 33 on the tread surface and the extending direction at the bottom of the sipe 33 intersect each other. In addition, the extending direction on the tread surface of the sipe 33 is a direction in which the entire sipe including the zigzag or wave-shaped portion and the linear portions on both sides thereof extends, for example, the extending direction of the linear portion.

  In the pneumatic tire, the sipe 33 has a three-dimensional structure that includes a zigzag or wavy portion on the tread surface and converges substantially linearly at the bottom, so that the tire rolls as shown in FIG. At the time of stepping and kicking off, the sipe 33 opens with the bottom as a base point and allows the shoulder land portion 30 to be bent finely with respect to the change in the curvature of the tread portion T in the tire circumferential direction. Therefore, it is possible to suppress the tensile deformation of the tread rubber in the tire circumferential direction, thereby reducing the rolling resistance. In particular, the rolling resistance can be effectively reduced by disposing the sipe 33 on the shoulder land portion 30 where the change in curvature of the tread portion T is the largest during tire rolling.

  When a plurality of sipes are added to the shoulder land portion 30, the ability to support lateral input may decrease, but the sipe 33 includes a zigzag or wavy portion on the tread surface, and the sipe Since the extension direction at the tread surface of 33 and the extension direction at the bottom part cross each other, the fall of the shoulder land part 30 is suppressed with respect to the lateral input, and steering stability is sufficiently ensured. Can do.

  The length W1 in the tire width direction on the tread surface of the zigzag or corrugated portion with respect to the length W0 in the tire width direction on the tread surface of the sipe 33 is a relationship of W1 / W0 = 0.40-0.80. It has become. As a result, it is possible to ensure sufficient steering stability and prevent block chipping. If W1 / W0 is less than 0.40, the ability to support lateral input is reduced, so steering stability is reduced. Conversely, if it exceeds 0.80, the end of the sipe 33 is zigzag or wavy. Are close to each other, so that it is easy to cause a block defect in a portion divided by the sipe 33.

  The sipe 33 is formed in a zigzag shape in which a first segment 33a positioned on the tire width direction center side on the tread surface and a second segment 33b positioned on the outer side in the tire width direction are formed, and the first segment 33a and the second segment 33b are formed. The angle of inclination of the segment 33b with respect to the tire circumferential direction is different from each other. When the inclination toward the center in the tire width direction is positive, the inclination angle α of the first segment 33a is set in the range of 30 ° to 70 °, and the inclination angle β of the second segment 33b is −30 ° to 10 °. It is good to set in the range of °. In this case, the first segment 33a having a relatively large inclination angle α with respect to the tire circumferential direction suppresses the tensile deformation of the tread rubber so that the sipe 33 can be easily opened in the tire circumferential direction, while the inclination angle β with respect to the tire circumferential direction. Therefore, it is possible to effectively support the lateral input by the second segment 33b having a relatively small value, and it is possible to suppress a decrease in steering stability. Such an effect is particularly effective in a tire in which the rotation direction R is designated.

  The depth of the sipe 33 at least at a position communicating with the circumferential groove 3 is set in a range of 70% to 100% of the maximum depth of the circumferential groove 3. This makes it possible to maximize the rolling resistance reduction effect. If the depth of the sipe 33 at least at a position communicating with the circumferential groove 3 is less than 70% of the maximum depth of the circumferential groove 3, the opening of the sipe 33 at the time of rolling of the tire becomes insufficient, so that rolling resistance is reduced. The reduction effect becomes insufficient. Conversely, even if it exceeds 100%, no further effect can be expected. Note that the portion of the sipe 33 having the depth defined as described above is desirably 50% or more of the sipe length.

  The angle θ1 of the extending direction at the bottom of the sipe 33 with respect to the tire circumferential direction is set in a range of 80 ° to 100 °, and the angle θ2 of the extending direction at the tread surface of the sipe 33 with respect to the extending direction at the bottom of the sipe 33 is 20 It is set in the range of ° to 50 °. By making the angle θ1 at the bottom of the sipe approach 90 °, the sipe 33 is easily opened in the tire circumferential direction during tire rolling, and the effect of reducing rolling resistance can be enhanced. When the angle θ1 is out of the above range, the sipe 33 is difficult to open in the tire circumferential direction at the time of stepping and kicking out when the tire rolls. On the other hand, by setting the angle θ2 on the tread surface in the range of 20 ° to 50 °, it is possible to enhance the ability to support the lateral input on the ground surface and sufficiently ensure the steering stability. Here, when the angle θ2 is less than 20 °, the ability to support the lateral input is reduced. Conversely, when the angle θ2 exceeds 50 °, the sipe 33 moves in the tire circumferential direction when the tire rolls and kicks out. It becomes difficult to open.

  A sipe having a three-dimensional structure can be provided in a land portion other than the shoulder land portion. FIG. 4 is a development view showing a modification of FIG. In FIG. 4, a plurality of sipes 23 extending in the tire width direction are formed in the intermediate land portion 20 instead of the lug grooves 21. One end of each sipe 23 communicates with the outer circumferential groove 3 and the other end communicates with the inner circumferential groove 2. The sipe 23 has a three-dimensional structure that includes a zigzag or wavy portion on the tread surface and converges substantially linearly at the bottom. In addition, the extending direction on the tread surface of the sipe 23 and the extending direction at the bottom part are in a relation of crossing each other.

  Thus, by providing the sipe 23 having a three-dimensional structure also in the intermediate land portion 20 positioned inside the shoulder land portion 30, the deformation of the shoulder land portion 30 can be promoted, and the effect of reducing rolling resistance can be enhanced. . The size and angle of the sipe 23 may be set according to the sipe 33 described above.

  FIG. 5 is a developed view showing one side of the tire equator line CL of the tread pattern of the pneumatic tire according to another embodiment of the present invention. FIG. 6 is an enlarged view showing a composite groove formed by connecting the lug groove and the sipe shown in FIG. The same components as those in FIGS. 1 to 4 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 5, the shoulder land portion 30 is formed with a plurality of composite grooves 34 formed by connecting lug grooves 31 and sipes 33 extending in the tire width direction. The end portions on the sipe side of the composite grooves 34 communicate with the inner circumferential groove 3, and the end portions on the lug groove side extend to the outside of the ground contact E. The sipe 33 has a three-dimensional structure that includes a zigzag or wavy portion on the tread surface and converges substantially linearly at the bottom (see FIG. 6). In addition, the extending direction of the sipe 33 on the tread surface and the extending direction at the bottom of the sipe 33 intersect each other.

  In the pneumatic tire, the sipe 33 of the composite groove 34 has a three-dimensional structure that includes a zigzag or wavy portion on the tread surface and converges substantially linearly at the bottom, so as shown in FIG. Since the sipe 33 opens from the bottom portion to allow the shoulder land portion 30 to be bent finely, the tread portion T is open from the bottom when the tread portion is stepped on and kicked out. The tensile deformation in the tire circumferential direction of the tread rubber can be suppressed, thereby reducing the rolling resistance. In particular, the rolling resistance can be effectively reduced by disposing the composite groove 34 including the lug groove 31 and the sipe 33 in the shoulder land portion 30 where the curvature change of the tread portion T is the largest when the tire rolls. .

  When a plurality of composite grooves composed of lug grooves and sipes are added to the shoulder land portion 30, there is a risk that the ability to support lateral input may be reduced, but the sipes 33 are zigzag or wavy on the tread surface. And the extension direction on the tread surface of the sipe 33 and the extension direction on the bottom part of each other intersect each other. Sufficient stability can be ensured.

  The length W11 in the tire width direction in the contact region of the lug groove 31 with respect to the length W10 in the tire width direction in the contact region of the shoulder land portion 30 is W11 / W10 = 0.40-0.80. It has become. Thereby, steering stability can be secured and drainage can be secured. When W11 / W10 is less than 0.40, the drainage performance is reduced because the ratio of the lug groove 31 in the ground contact area is small, and conversely, when it exceeds 0.80, the ability to support the lateral input is reduced. Stability is reduced.

  The depth of the sipe 33 constituting the composite groove 34 is set in a range of 80% to 100% of the maximum depth of the lug groove 31 connected thereto. This makes it possible to maximize the rolling resistance reduction effect. If the depth of the sipe 33 is less than 80% of the maximum depth of the lug groove 31, the opening of the sipe 33 at the time of tire rolling becomes insufficient, so that the effect of reducing rolling resistance becomes insufficient. This will cause cracks at the bottom of the sipe, and if it exceeds 100%, no further effect can be expected.

  The composite groove composed of a sipe and a lug groove having a three-dimensional structure can be provided in a land portion other than the shoulder land portion. FIG. 8 is a development view showing a modification of FIG. In FIG. 8, the intermediate land portion 20 is formed with a plurality of composite grooves 24 formed by connecting lug grooves 21 and sipes 23 extending in the tire width direction. One end of each of the composite grooves 24 communicates with the outer circumferential groove 3 and the other end communicates with the inner circumferential groove 2. The sipe 23 constituting the composite groove 24 has a three-dimensional structure that includes a zigzag or wavy portion on the tread surface and converges substantially linearly at the bottom. In addition, the extending direction on the tread surface of the sipe 23 and the extending direction at the bottom part are in a relation of crossing each other.

  In this way, the intermediate land portion 20 located inside the shoulder land portion 30 is also provided with the composite groove 24 composed of the sipe 23 and the lug groove 21 having a three-dimensional structure, thereby promoting the deformation of the shoulder land portion 30. The effect of reducing rolling resistance can be enhanced. The size and angle of the sipe 23 may be set according to the sipe 33 described above.

  In a pneumatic tire having a tire size of 195 / 65R15, provided with a plurality of circumferential grooves extending in the tire circumferential direction in the tread portion, and dividing a plurality of rows of land portions by these circumferential grooves, as shown in FIG. The shoulder land portion is provided with a plurality of sipes extending in the tire width direction, the sipe has a three-dimensional structure that includes a zigzag portion on the tread surface and converges substantially linearly at the bottom, and the sipe tread The extending direction at the surface and the extending direction at the bottom cross each other, and the angle θ1 of the extending direction at the bottom of the sipe, the angle θ2 of the extending direction at the tread surface of the sipe, and the first segment of the sipe The angle α, the angle β of the second segment of the sipe, the length W0 in the tire width direction on the tread surface of the sipe, and the tire width of the zigzag portion on the tread surface of the sipe The length W1 of the direction to produce the tires of Examples 1 and 2 were set as shown in Table 1.

  For comparison, a tire in which the sipe having the three-dimensional structure is deleted from the shoulder land portion (Comparative Example 1) and a tire in which a straight sipe is provided in place of the sipe having the three-dimensional structure in the shoulder land portion (comparison) Example 2) and a tire (Comparative Example 3) provided with a sipe having a zigzag shape instead of a sipe having the above three-dimensional structure on the shoulder land portion were prepared.

  These tires were evaluated for rolling resistance and steering stability by the following evaluation methods, and the results are also shown in Table 1.

Rolling resistance:
The test tire was assembled on a wheel having a rim size of 15 × 6 J, and rolling resistance was measured under the conditions of an air pressure of 180 kPa (JATMA standard air pressure), a load of 4.5 kPa, and a drum rotation speed of 80 KM / h. The evaluation results are shown as an index using Comparative Example 1 as 100, using the reciprocal of the measured value. It means that rolling resistance is so small that this index value is large.

Steering stability:
The test tire was assembled on a wheel with a rim size of 15 × 6J and mounted on an FR vehicle with a displacement of 2000 cc. The air pressure was 180 kPa, and the driving stability of the test driver was evaluated. The evaluation results are shown as an index with Comparative Example 1 as 100. The larger the index value, the better the steering stability.

  As is clear from Table 1, the tires of Examples 1 and 2 were able to reduce rolling resistance while minimizing a decrease in steering stability in comparison with Comparative Example 1. On the other hand, in the tire of Comparative Example 2, although the rolling resistance reduction effect was recognized, the steering stability was significantly reduced. The tire of Comparative Example 3 was insufficient in reducing rolling resistance.

  Next, in the pneumatic tire in which the tire size is 195 / 65R15, a plurality of circumferential grooves extending in the tire circumferential direction are provided in the tread portion, and a plurality of rows of land portions are partitioned by the circumferential grooves, FIG. As shown in the figure, a plurality of compound grooves formed by connecting lug grooves and sipes extending in the tire width direction are provided on the shoulder land portion, and the sipes include a zigzag portion on the tread surface and are substantially linear at the bottom portion. The extension direction at the tread surface of the sipe and the extension direction at the bottom part intersect each other, and the angle θ1 of the extension direction at the bottom part of the sipe, The angle θ2 in the extending direction of the sipe, the angle α of the first segment of the sipe, the angle β of the second segment of the sipe, the length W10 in the tire width direction within the ground contact region of the shoulder land, and the ground contact region of the lug groove The tire width direction of the length W11 were produced tires of Examples 11 and 12 were set as shown in Table 2 in.

  For comparison, a tire in which the sipe having the three-dimensional structure is deleted from the shoulder land portion (Comparative Example 11) and a tire in which a straight sipe is provided in place of the sipe having the three-dimensional structure in the shoulder land portion (comparison) Example 12) and a tire (Comparative Example 13) provided with a sipe having a zigzag shape instead of the sipe having the above three-dimensional structure on the shoulder land portion were prepared.

  These tires were evaluated for rolling resistance and steering stability by the same evaluation method as described above, and the results are also shown in Table 2. However, the reference of the evaluation result was set to Comparative Example 11.

  As is apparent from Table 2, the tires of Examples 11 and 12 were able to reduce rolling resistance while minimizing the decrease in steering stability in comparison with Comparative Example 11. On the other hand, in the tire of Comparative Example 12, although the rolling resistance reduction effect was recognized, the steering stability was significantly reduced. The tire of Comparative Example 13 was insufficient in reducing rolling resistance.

It is an expanded view which shows the one side bordering on the tire equator line CL of the tread pattern of the pneumatic tire which consists of embodiment of this invention. It is an enlarged view which shows the sipe of FIG. It is explanatory drawing which shows the behavior of the tread part at the time of the tire of FIG. 1 rolling. It is an expanded view which shows the modification of FIG. It is an expanded view which shows the one side bordering on the tire equator line CL of the tread pattern of the pneumatic tire which consists of other embodiment of this invention. It is an enlarged view which shows the sipe of FIG. It is explanatory drawing which shows the behavior of the tread part at the time of the tire of FIG. 5 rolling. It is an expanded view which shows the modification of FIG.

Explanation of symbols

1, 2, 3 Circumferential groove 10, 20, 30 Land part 11, 21, 31 Lug groove 12, 22, Block 23, 33 Sipe 24, 34 Compound groove CL Tire equator line E Grounding end T Tread part

Claims (16)

  In the pneumatic tire in which a plurality of circumferential grooves extending in the tire circumferential direction are provided in the tread portion and a plurality of rows of land portions are partitioned by the circumferential grooves, a plurality of rows extending in the tire width direction are provided in at least one row of the land portions. Sipes are provided, and these sipes have a three-dimensional structure that includes a zigzag or wavy portion on the tread surface and converges substantially linearly at the bottom, and the sipe extends in the tread surface and in the bottom. A pneumatic tire characterized in that the directions intersect each other.   The sipe is arranged in a shoulder land portion located on the outermost side in the tire width direction, and one end of the sipe is communicated with an inner circumferential groove in the shoulder land portion, and the other end is extended to the outside of the ground contact end. The pneumatic tire according to claim 1.   The said sipe is arrange | positioned in the intermediate land part located inside the said shoulder land part, and the both ends of the said sipe are connected to the circumferential groove | channel of both sides in this intermediate land part, respectively. Pneumatic tire.   The pneumatic tire according to any one of claims 1 to 3, wherein the sipe is disposed at least on a shoulder land portion inside the vehicle when the vehicle is mounted.   The relation W1 / W0 = 0.40-0.80 is the length W1 in the tire width direction on the tread surface of the zigzag or wavy portion with respect to the length W0 in the tire width direction on the tread surface of the sipe. The pneumatic tire according to any one of claims 1 to 4, wherein the pneumatic tire is made.   The sipe is formed in a zigzag shape in which a first segment located on the tire width direction center side on the tread surface and a second segment located on the outer side in the tire width direction are repeated, and the tire circumference of the first segment and the second segment The inclination angle with respect to the direction is made different from each other, the inclination angle of the first segment is set in a range of 30 ° to 70 °, and the inclination angle of the second segment is set in a range of −30 ° to 10 °. The pneumatic tire according to any one of claims 1 to 5.   7. The depth of the sipe at a position communicating with at least the circumferential groove is set in a range of 70% to 100% of the maximum depth of the circumferential groove. 7. Pneumatic tires.   The extension direction at the bottom of the sipe is set in a range of 80 ° to 100 ° with respect to the tire circumferential direction, and the extension direction at the tread surface of the sipe is set to 20 ° to the extension direction at the bottom of the sipe. The pneumatic tire according to any one of claims 1 to 7, wherein the pneumatic tire is set in a range of 50 °.   In the pneumatic tire in which a plurality of circumferential grooves extending in the tire circumferential direction are provided in the tread portion and a plurality of rows of land portions are partitioned by the circumferential grooves, lug grooves extending in the tire width direction in at least one row of the land portions; Provided with a plurality of composite grooves connected to the sipe, the sipe has a three-dimensional structure that includes a zigzag or wavy portion on the tread surface and converges substantially linearly at the bottom, and A pneumatic tire characterized in that the extending direction at the tread surface and the extending direction at the bottom cross each other.   The composite groove is disposed on the shoulder land portion located on the outermost side in the tire width direction, and the end on the sipe side of the composite groove is communicated with the inner circumferential groove in the shoulder land portion, while the end on the lug groove side The pneumatic tire according to claim 9, wherein the portion is extended to the outside of the ground contact end.   The composite groove is disposed in an intermediate land portion located inside the shoulder land portion, and both ends of the composite groove are respectively communicated with circumferential grooves on both sides in the intermediate land portion. The described pneumatic tire.   The pneumatic tire according to any one of claims 9 to 11, wherein the composite groove is disposed at least in a shoulder land portion inside the vehicle when the vehicle is mounted.   The length W11 in the tire width direction in the ground contact area of the lug groove with respect to the length W10 in the tire width direction in the ground contact area of the shoulder land portion is W11 / W10 = 0.40-0.80. The pneumatic tire according to any one of claims 9 to 12, wherein the pneumatic tire is made.   The sipe is formed in a zigzag shape in which a first segment located on the tire width direction center side on the tread surface and a second segment located on the outer side in the tire width direction are repeated, and the tire circumference of the first segment and the second segment The inclination angle with respect to the direction is made different from each other, the inclination angle of the first segment is set in a range of 30 ° to 70 °, and the inclination angle of the second segment is set in a range of −30 ° to 10 °. The pneumatic tire according to any one of claims 9 to 13.   The pneumatic tire according to any one of claims 9 to 14, wherein a depth of the sipe is set in a range of 80% to 100% of a maximum depth of a lug groove connected to the sipe.   The extension direction at the bottom of the sipe is set in a range of 80 ° to 100 ° with respect to the tire circumferential direction, and the extension direction at the tread surface of the sipe is set to 20 ° to the extension direction at the bottom of the sipe. The pneumatic tire according to any one of claims 9 to 15, wherein the pneumatic tire is set in a range of 50 °.

Images