JP4316603B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire including a tread pattern in which a land portion having a so-called three-dimensional sipe is formed, and is particularly useful as a studless tire (winter tire).

  Conventionally, in order to improve the ice performance of a studless tire, a tire pattern in which a plurality of sipes are arranged in each part (center part, mediate part, shoulder part) is known. By forming such sipes in blocks, the edge effect, the water removal effect, and the adhesion effect are improved, and therefore the number of sipes tends to increase in recent years.

  However, if the number of sipes is increased to increase the sipe density, the number of edges increases, but the rigidity of the entire block decreases and the sipe collapses excessively. It becomes small and the problem that ice performance falls will arise. For this reason, a so-called 3D sipe (three-dimensional sipe) has been developed as a method for suppressing the collapse of the sipe.

  For example, Patent Document 1 below discloses a three-dimensional sipe in which uneven rows on the inner wall surface of a sipe are alternately inclined in the sipe longitudinal direction (lateral direction) and are zigzag in the depth direction. In this sipe, since the concavo-convex row has a zigzag amplitude in the horizontal direction, the effect of suppressing the horizontal movement of the block piece is large, and conversely, the effect of suppressing the movement in the front-rear direction is small.

  Further, Patent Document 2 below discloses a three-dimensional sipe in which a wavy sipe has a reference surface extending in the depth direction, and a concave engaging portion is provided on each of the front side top portion and the back side top portion. . In this sipe, since the concave engaging portions are provided on the front side top part and the back side top part, the effect of suppressing the movement of the block piece in the front-rear direction is large, and conversely, the effect of suppressing the lateral movement is small. .

Japanese Patent No. 3504632 Japanese Patent No. 3516647

  However, since the three-dimensional sipe as described above is premised on the same type of tread being provided in each part of the tread, when the three-dimensional sipe as described above is provided, the ice turning performance and the ice braking performance are reduced. It was difficult to achieve both. Also, with regard to the dry performance, it is difficult to achieve both turning performance and braking performance.

  Therefore, an object of the present invention is to provide a pneumatic tire that can achieve both ice turning performance and ice braking performance, and that can achieve both turning performance and braking performance in terms of dry performance.

The above object can be achieved by the present invention as described below.
That is, the pneumatic tire according to the present invention is a pneumatic tire having a tread pattern having a land portion in which a plurality of sipes are formed, and a region parallel to the tire equator line is provided in a region inside the tire equator line. And a first sipe having a concave or convex engaging portion (except for the one corresponding to the second sipe), and a region outside the tire equator line is inclined from the tire width direction or the tire width direction. An inner wall surface extending in the direction has a concavo-convex row, and a second sipe having a portion in which the concavo-convex row is inclined in the sipe formation direction is provided . The angle formed by the direction is 0 to 45 ° . Here, “inside of wearing” refers to the area inside the tire equator line when the tire is attached to the vehicle, and “outside of wearing” refers to the tire equator when the tire is attached to the vehicle. Refers to the area outside the line. The “sipe formation direction” refers to the direction of the sipe center line. For example, in the case of a wave sipe, the center line of the amplitude is the sipe formation direction.

  According to the pneumatic tire of the present invention, the first sipe that has a large effect of suppressing the movement in the front-rear direction is provided in the inner area of the tire equator line that greatly contributes to the braking performance, and contributes to the turning performance. On the outer area of the tire equator line where the tires are large, the second sipe that has a great effect of suppressing lateral movement is provided, so that both ice turning performance and ice braking performance can be achieved. Can also achieve both turning performance and braking performance. That is, since the first sipe has a concave or convex engagement portion in a cross section parallel to the tire equator line, an engagement effect is generated when the longitudinal force of the tire is generated, and the forward and backward movement is suppressed. The braking performance can be improved. Further, in the second sipe, the inner wall surface extending along the tire width direction or the direction inclined from the tire width direction has an uneven row, and the uneven row has a portion inclined in the sipe forming direction. When this occurs, the engagement effect of the concave and convex rows on the inner wall surface is produced, and the turning performance can be enhanced by suppressing the lateral movement.

  In general, when turning a vehicle, it is known that a high load is applied to a region outside the mounting. Conversely, in the region inside the mounting, the contribution to the braking performance is relatively high. In particular, most recent vehicles are negative camber vehicles (especially minivans). In this case, in the region on the inner side of the tire equator line, the load is greater than the outer side of the tire and the front and rear lengths of the contact surface are also longer. For this reason, in such a vehicle, it is particularly effective to provide the first sipe, which is particularly effective in suppressing the movement in the front-rear direction, in the region on the inner side of the mounting.

  In the above, it is preferable that the concavo-convex row of the inner wall surface is provided with a second sipe having a portion inclined to one side in the sipe formation direction and a portion inclined to the opposite side to the portion. By providing such a second sipe, when the lateral force of the tire is generated, the engagement effect of the uneven rows on the inner wall surface becomes greater, and the lateral movement is effectively suppressed to further improve the turning performance. Can do.

  Moreover, it is preferable that the said 1st sipe has the said recessed or convex engaging part in the top part of the front-back direction both sides of a waved sipe. By providing the concave or convex engaging portions at the tops on both sides in the front-rear direction of the wavy sipe, the engagement effect is increased when the front-rear force of the tire is generated, and the movement in the front-rear direction is effectively suppressed. The braking performance can be further increased.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a development view showing an example of a tread pattern in the pneumatic tire of the present invention. 2 to 3 are main part views showing an example of the first sipe in the pneumatic tire of the present invention, and FIGS. 5 to 6 are main parts showing an example of the second sipe in the pneumatic tire of the present invention. FIG.

  As shown in FIG. 1, the pneumatic tire of the present invention includes a tread pattern T having a land portion such as a block 1 in which a plurality of sipes 10 are formed. In the present embodiment, an example is shown in which blocks 1 divided by circumferential grooves 2, lateral grooves 3, 5 and oblique grooves 4 are formed, and six rows of blocks 1 are arranged in the tire width direction.

  Each block 1 is formed with a plurality of rows of sipes 10 in the tire width direction, and both ends of each of the sipes 10 are open in grooves adjacent to the block 1, but are not limited thereto. Instead, it can be properly used depending on the pattern configuration, for example, it is not exposed from the side wall of the block 1 but is fastened inside the side wall of the block 1 or only one side is fastened.

  The pneumatic tire of the present invention has a first sipe 10 (second sipe) having a concave or convex engaging portion 11 in a cross section parallel to the tire equator line CL in a region Ai inside the tire equator line CL. Except those corresponding to 20). In this embodiment, as shown in FIGS. 2 to 3, the first sipe 10 has an example in which concave engaging portions 11 are provided on the top portions 10 a and 10 b on both sides in the front-rear direction of the wave sipe. In this embodiment, instead of the concave engaging portion 11, a convex engaging portion 11 may be provided.

  From the viewpoint of improving ice braking performance and dry braking performance, the first sipe 10 preferably occupies 60% or more, more preferably 80% or more, of the types provided in the region Ai on the inner side of the mounting. % Or more is more preferable.

  The first sipe 10 has a reference plane B extending in the depth direction from a wavy line on the surface of the block 1, and the reference plane B has substantially the same cross-sectional shape at any depth. The wavy lines are not limited to those close to a sine wave, and may be any shape such as a wavy line obtained by alternately combining straight lines and curves, a rectangular wave, or a zigzag shape.

  The period of the wavy line is preferably 1.5 to 4 mm for suitably expressing the so-called waveform sipe characteristics, and the amplitude (the sum of the heights of the tops on both sides) is preferably 1 to 2 mm. The depth of the first sipe 10 is preferably 3 to 10 mm.

  The front side top portion 10a of the reference surface B is provided with an engaging portion 11a having a concave longitudinal section as shown in FIG. 2B, and the back side top portion 10b has a longitudinal section as shown in FIG. 2C. Is provided with a concave engaging portion 11b. Both the engaging portion 11a and the engaging portion 11b are formed as conical concave surfaces.

  In the present invention, although depending on the shapes of the engaging portions 11a and 11b, the maximum depth D from the reference plane B of the engaging portions 11a and 11b of the first sipe 10 as shown in FIG. It is preferable that it is 1.5 mm. If the maximum depth D is less than 0.5 mm, the effect of suppressing the collapse of the first sipe 10 tends to be insufficient, and if it exceeds 1.5 mm, the resistance tends to increase during demolding after tire vulcanization molding. is there.

  Moreover, it is preferable that the maximum distance W1 in the depth direction of the boundary line 12 between the engaging portions 11a and 11b and the reference plane B is 0.5 to 2.5 mm. If the maximum distance W1 is less than 0.5 mm, the effect of suppressing the collapse of the block 1 tends to be insufficient, and if it exceeds 2.5 mm, the engagement portions 11a and 11b are relatively related to the maximum depth D. Since the inclination angle of the block 1 becomes small, the effect of suppressing the collapse of the block 1 tends to be insufficient.

  When a plurality of engaging portions 11a and 11b are provided on the upper and lower sides, the vertical distance between the maximum depth portions is preferably 0.5 to 1.5 mm. Moreover, although the engaging part 11a and the engaging part 11b may be provided at different heights, it is preferable to provide the engaging parts at the same height in order to reduce the influence of the falling direction of the block.

  In the present invention, the smaller the groove width of the first sipe 10, the greater the effect of suppressing the collapse of the block 1 by the engaging portion, but if the groove width is too small, the edge portion is less likely to occur and the edge effect is reduced. The groove width is preferably 0.2 to 0.7 mm.

In the present invention, since the effect of suppressing the collapse of the block 1 by the engaging portions 11a and 11b is great, the edge effect can be further enhanced by increasing the number of edges and increasing the sipe density by increasing the number of the first sipes 10. . From such a viewpoint, in the present invention, a sipe density of 0.1 to 0.3 mm / mm ² is preferable, and 0.15 to 0.3 mm / mm ² is more preferable.

  For example, the engaging portion 11 of the first sipe 10 may be as shown in FIGS. 4 (a1) to 4 (b2). 4 (a1) and (b1) are vertical cross-sectional views, and (a2) and (b2) in FIG. 4 are front views of the protruding side wall facing the sipe.

  4 (a1) and 4 (a2) are examples in which the engaging portion 11 having a concave longitudinal section is formed of a hemispherical concave surface. With a hemispherical concave surface, it is easier to obtain a higher engagement force than a conical concave surface.

  4 (b1) and 4 (b2) show an example in which the engaging portion 11 having a concave longitudinal section is formed by two concave surfaces that are substantially perpendicular to each other and whose boundary line is horizontal. In this engaging portion 11, the engaging force in the lateral direction (the direction perpendicular to the paper surface in FIG. 4B1) is small, but the reference surface B of the first sipe 10 is corrugated, so the engaging force in the lateral direction is You can get enough. Similarly to the above, the engaging portion may be formed by a concave surface made of a horizontal cylindrical surface.

  On the other hand, in the pneumatic tire of the present invention, in the region Ao outside the tire equator line CL, the inner wall surface 23 extending along the tire width direction WD or the direction inclined from the tire width direction has an uneven row, A second sipe 20 having a portion in which the concavo-convex row is inclined in the sipe formation direction is provided. In the present embodiment, as shown in FIGS. 5 to 6, the concave-convex row of the inner wall surface 23 is inclined in the tire width direction WD on one side, and the first portion S1 is inclined on the opposite side. An example in which the second sipe 20 having the second portion S2 is provided is shown.

  From the viewpoint of improving the ice turning performance and the dry turning performance, the second sipe 20 preferably occupies 60% or more, more preferably 80% or more, of the types provided in the region Ao outside the mounting. % Or more is more preferable.

  FIG. 5 is a partially broken perspective view showing the main part of the block according to the present invention. In FIG. 5, a part of the block 1 is broken to expose the inner wall surface 23 of the second sipe 20 so that the uneven shape of the inner wall surface 23 can be easily understood.

  In the present embodiment, the first portion S1, the second portion S2, and the first portion S1 are sequentially arranged in the depth direction, and the boundary line between the first portion S1 and the second portion S2 is the land tread 1a. The example which provided the 2nd sipe 20 located in the surface parallel to is shown.

  The cross-sectional shape perpendicular to the concavo-convex row of the second sipe 20 is not limited to a shape close to a sine wave, and may be any shape such as a wavy line obtained by alternately combining a straight line and a curve, a rectangular wave, or a shape close to a zigzag shape. . The period of the unevenness in this cross-sectional shape (for example, the distance between the convex and convex tops) is preferably 1.5 to 5 mm for suitably expressing the characteristics of the so-called corrugated sipe, and the amplitude (the sum of the heights of both side tops) Is preferably 1.5 to 5 mm.

  The period and amplitude of the unevenness of the first part S1 and the second part S2 may be the same or different, but it is preferable that the period and amplitude of both are the same. Moreover, when changing the period and amplitude of 1st part S1 and 2nd part S2, it is preferable to adjust a period and amplitude so that both boundary parts may continue. Thereby, both can be smoothly connected by the wavy boundary line, and the inclination direction of the concave-convex row of the first portion S1 and the inclination direction of the second portion S2 are set in the normal direction of the land portion tread 1a. It can be asymmetrical.

  Next, the size of each part will be described. The width in the normal direction of each of the first portion S1 or the second portion S2 in the present invention is preferably 1.5 to 3 mm. The total depth of the second sipe 20 is preferably 40 to 80% of the main groove depth, that is, 4 to 8 mm. Therefore, the number of consecutive stages of the first part S1 and the second part S2 is preferably 2 to 4, and more preferably 3 stages.

  Moreover, 30-70 degrees is preferable and, as for the inclination angle with respect to the normal line direction of each 1st part S1 or 2nd part S2, 45 degrees is the most preferable. If the angle is smaller than 30 °, the engaging action between the ridges and the concave ridges of the sipe inner wall surface 23 when the block is collapsed tends to be small, and if it is larger than 70 °, a bending force is relatively generated near the ground contact surface. The length tends to increase, and the contact pressure tends to be uneven in the block.

  The groove width of the second sipe 20 is preferably 0.2 to 0.7 mm, more preferably 0.2 to 0.4 mm, in order to appropriately express the edge effect while appropriately suppressing the collapse of the block.

In the present invention, the effect of suppressing the collapse of the block 1 by the second portion 22 is great, so that the edge effect can be further enhanced by increasing the number of the second sipes 20 and increasing the sipe density to increase the number of edges. From such a viewpoint, in the present invention, a sipe density of 0.1 to 0.3 mm / mm ² is preferable, and 0.15 to 0.25 mm / mm ² is more preferable.

  Usually, a plurality of second sipes 20 are formed for one block 1, but adjacent second sipes 20 may have the same shape or different wave shapes, inclination angles, uneven periods, and amplitudes. However, in order to improve the demoldability after vulcanization molding, it is preferable that the adjacent second sipes 20 have the same shape.

  In the present invention, the first part and the second part need only have parts that are alternately arranged in the depth direction of the sipe. For example, the sipe shown in FIGS. Shape may be sufficient. In this figure, the ridges protruding from the back side of the paper surface are shown as 11 and the ridges protruding from the front side of the paper surface are shown as 12 in the sipe unevenness row.

  In FIG. 7A, the first portion S1 and the second portion S2 are continuously provided, and a third portion S3 is further provided on the side of the tread and further extending in the normal direction of the land portion tread. This is an example. Even in the case of this sipe, the first portion S1 and the second portion S2 can obtain the engaging action between the ridges and the ridges on the sipe inner wall surface when the block is collapsed. Further, the presence of the third portion S3 does not increase the bending length acting on the second portion S2, so that the uniformity of the ground pressure in the block can be improved as in the case of the above-described embodiment.

  FIG. 7B shows an example in which the number of consecutive stages of the first part S1 and the second part S2 is four. In the case of this sipe, the uniformity of the ground pressure in the block can be further improved as compared with the case of the three-stage configuration.

  In FIG. 7C, instead of directly connecting the first part S1 and the second part S2, the first part S1 and the second part S2 are connected through a short fourth part S4. This is an example. As 4th part S4, the shape which the corrugated sipe which an uneven | corrugated row | line extends in the normal line direction of a land part tread, and the shape which continues 1st part S1 and 2nd part S2 on a curved surface may be sufficient. By interposing such fourth portion S4, it is possible to improve the demoldability after vulcanization molding while maintaining the effect of suppressing the collapse of the block and the uniformity of the contact pressure in the block to some extent.

  The pneumatic tire of the present invention is the same as a normal pneumatic tire except that it includes the tread pattern T as described above, and any conventionally known material, shape, structure, manufacturing method, and the like can be employed in the present invention.

  The pneumatic tire of the present invention is particularly useful as a studless tire because it exhibits the above-described effects and is excellent in ice performance.

[Other Embodiments]
Hereinafter, other embodiments of the present invention will be described.

  (1) In the above-described embodiment, the example in which the block having the shape shown in FIG. 1 is formed is shown. However, the block is not limited to this shape, and is substantially square, parallelogram, V-shaped, pentagon, Alternatively, a curve-based block may be used. Further, instead of the block, a rib extending linearly in the tire circumferential direction, a rib extending zigzag in the tire circumferential direction, or a lug may be formed.

  (2) In the above-described embodiment, an example in which a plurality of rows of sipes are formed in the tire width direction is shown. However, the sipe formation direction (the direction of the center line) may be a direction inclined from the tire width direction. . However, from the viewpoint of achieving both tire turning performance and braking performance, the angle formed by the sipe formation direction and the tire width direction is preferably 0 to ± 45 °, more preferably 0 to ± 20 °, and more preferably 0 to ± 10 °. Is more preferable.

  (3) In the above-described embodiment, the sipe is formed so as to be perpendicular to the block surface. However, the sipe is slightly inclined (for example, 15 ° or less) with respect to the normal of the block surface. May be.

  (4) In the above-described embodiment, the example in which the sipe in which the unevenness of the inner wall surface in the present invention is inclined in a zigzag shape is applied to all the sipes in the tread pattern is shown. The present invention may be applied only to the sipe, or may be applied only to a land portion such as a part of a plurality of blocks. When the sipe according to the present invention is applied to only a part of the blocks, it is particularly effective to apply the blocks to the blocks provided in the shoulder portion of the tire.

  (5) In the above-described embodiment, the example of the first sipe shown in FIGS. 2 to 4 has been shown. However, as the first sipe, a concave or convex engagement portion is provided in a cross section parallel to the tire equator line. Any sipe described in the following patent document can be applied to the present invention.

  That is, examples of the first sipe include JP-A-4-310407, JP-A-5-58118, JP-A-12-6619, JP-A-10-80923, JP-A-12-177330, and the like. Disclosed in (1).

  (6) Although the example of the 2nd sipe shown in FIGS. 5-7 was shown in above-mentioned embodiment, as the 2nd sipe, the inner wall surface extended along a tire width direction has an uneven | corrugated row | line | column, Any sipe described in the following patent document can be applied to the present invention as long as the row has a portion inclined in the tire width direction.

  That is, examples of the second sipe include those disclosed in JP-A-10-258615, JP-A-11-208223, and Japanese Patent No. 3504632.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below. In addition, each performance evaluation of the tire was performed as follows.

(1) Ice braking performance Tires are mounted on a real vehicle (domestic 3000cc class FR sedan), run on a frozen road under the load condition of one passenger, and ABS is applied by applying braking force at a speed of 40km / h. The braking distance was evaluated with an index. In addition, evaluation is shown by an index display when the conventional product (Comparative Example 1) is set to 100, and a larger value indicates a better result.

(2) Ice turning performance Mount the tire on the same actual vehicle as in (1) above, run on the same road surface under the load condition of 1 person riding on the Lemnis skate curve (eight curve: R = 25m yen), and the lap time Evaluated by index. In addition, evaluation is shown by an index display when the conventional product (Comparative Example 1) is set to 100, and a larger value indicates a better result.

(3) Dry braking performance When the tire is mounted on the same actual vehicle as in (1) above, the ABS is operated by applying braking force at a speed of 100 km / h while running on the dry road surface under the load condition of one passenger. The braking distance was evaluated with an index. In addition, evaluation is shown by an index display when the conventional product (Comparative Example 1) is set to 100, and a larger value indicates a better result.

(4) Dry turning performance Tires are mounted on the same actual vehicle as in (1) above, and the driving stability is achieved by running on a dry road surface on a dry road surface (8-shaped curve: R = 25m yen) under the load conditions of one passenger. The sensory test was conducted and evaluated by an index. In addition, evaluation is shown by an index display when the conventional product (Comparative Example 1) is set to 100, and a larger value indicates a better result.

Comparative example 1 (conventional product)
In the tread pattern shown in FIG. 1, a normal corrugated sipe (with a surface groove shape extending in the depth direction) having the following dimensions was formed to produce a radial tire of size 205 / 65R15. Table 1 shows the results of each performance evaluation described above using this tire. The sipe depth was 7 mm, the sipe groove width was 0.3 mm, the period was 4 mm, the amplitude was 1.8 mm, and the sipe interval was 4 mm.

Comparative Example 2
A radial tire having a size of 205 / 65R15 was manufactured by forming sipes as shown in FIG. 2 on the inner and outer regions of the tread pattern shown in FIG. Table 1 shows the results of each performance evaluation described above using this tire. At that time, the sipe depth is 7 mm, the sipe groove width is 0.3 mm, the period is 4 mm, the amplitude is 1.8 mm, the sipe interval is 4 mm, the depth of the engaging portion from the block surface is 3 mm and 6 mm, and the radius is 0.75 mm. A conical concave engaging portion having a depth of 1.00 mm was formed.

Comparative Example 3
In the tread pattern shown in FIG. 1, a radial tire of size 205 / 65R15 was manufactured by forming sipes as shown in FIG. Table 1 shows the results of each performance evaluation described above using this tire. At that time, the depth of the entire sipe is 6.9 mm, the groove width is 0.3 mm, the sipe interval is 4 mm, the amplitude of the upper and lower first parts is 1.5 mm, the period is 4.0 mm, the width in the normal direction is 2.3 mm, the inclination The angle was 45 °, the amplitude of the second portion was 1.5 mm, the period was 4.0 mm, the width in the normal direction was 2.3 mm, and the inclination angle was 45 °.

Example 1
In the tread pattern shown in FIG. 1, a first sipe as shown in FIG. 2 is formed on the inner area of the mounting (the dimensions are the same as those in Comparative Example 2), and a second sipe as shown in FIG. 5 is formed on the outer area of the mounting. Sipes (sizes are the same as in Comparative Example 3) were formed to produce radial tires of size 205 / 65R15. Table 1 shows the results of each performance evaluation described above using this tire.

Example 2
In Example 1, instead of the first sipe shown in FIG. 2, a conical convex engaging portion having a radius of 0.75 mm and a depth of 1.00 mm is formed at the top of the wave sipe. A first sipe was formed in the same manner as in Example 1 to produce a radial tire of size 205 / 65R15. Table 1 shows the results of each performance evaluation described above using this tire.

Example 3
Example 1 is the same as Example 1 except that instead of the first sipe shown in FIG. 2, a conical concave engaging portion having a radius of 0.75 mm and a depth of 1.00 mm is formed on a straight sipe. A first sipe was formed to produce a radial tire of size 205 / 65R15. Table 1 shows the results of each performance evaluation described above using this tire.

Comparative Example 4
In Example 1, a radial tire was manufactured in the same manner as in Example 1 except that the second sipe was formed on the inner region of the mounting and the first sipe was formed on the outer region of the mounting. Table 1 shows the results of each performance evaluation described above using this tire.

  As the result of Table 1 shows, in Examples 1-3, ice turning performance and ice braking performance can be made compatible, and turning performance and braking performance can be made compatible also about dry performance. On the other hand, in Comparative Examples 2 to 3 in which the same three-dimensional sipe was formed on the inner side and the outer side, the effect of improving either the ice turning performance or the ice braking performance was small, and the dry performance was the same result. It was. Further, in Comparative Example 4 in which the sipes provided on the inner side and the outer side were reversed, the effects of improving both the ice turning performance and the ice braking performance were small, and the dry performance was the same.

The expanded view which shows an example of the tread pattern in the pneumatic tire of this invention It is a principal part enlarged view which shows the block of the tread surface of FIG. 1, (a) is the perspective view which fractured | ruptured partially, (b) is II sectional view taken on the line in (a), (c) is (a). II-II arrow cross-sectional view in The principal part enlarged view for demonstrating the relationship between the reference plane and engagement part in this invention The principal part enlarged view which shows the other example of the 1st sipe in this invention. The partially broken perspective view which shows the principal part of the block which formed the 2nd sipe in this invention It is a schematic diagram of the 2nd sipe in this invention, (a) is a cross section of a sipe, (b) is a schematic diagram of an ungrounded state, (c) is a schematic diagram of a grounded state The schematic diagram which shows the other example of the 2nd sipe in this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Block 1a Land part tread 10 1st sipe 10a Front side top part 10b Back side top part 11 Engagement part 11a Engagement part (front side top part)
11b Engagement part (back side top)
20 2nd sipe S1 1st part of 2nd sipe S2 2nd part of 2nd sipe 23 Sipe inner wall surface B Reference plane D Maximum depth of engaging part W1 Maximum interval T Tread pattern CL Tire equator line PD Tire circumferential direction WD Tire width direction

Claims (3)

In a pneumatic tire provided with a tread pattern having a land portion in which a plurality of sipes are formed,
In the region on the inner side of the tire equator line, there is provided a first sipe (excluding the one corresponding to the second sipe) having a concave or convex engaging portion in a cross section parallel to the tire equator line,
In the outer region of the tire equator line, the inner wall surface extending along the tire width direction or the direction inclined from the tire width direction has a concavo-convex row, and the concavo-convex row has a portion inclined in the sipe formation direction. Set up sipes ,
In the first sipe and the second sipe, an angle formed by a sipe formation direction and a tire width direction is set to 0 to 45 ° .   2. The pneumatic tire according to claim 1, wherein the concave-convex row of the inner wall surface is provided with a second sipe having a portion inclined to one side in the sipe formation direction and a portion inclined to the opposite side to the portion.   3. The pneumatic tire according to claim 1, wherein the first sipe has the concave or convex engaging portions at tops on both sides in the front-rear direction of the wave sipe.

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