JP7119529B2 - pneumatic tire - Google Patents

Description

The present invention relates to pneumatic tires.

BACKGROUND ART A pneumatic tire employs a tread pattern in which a plurality of main grooves extending in the tire circumferential direction are provided in a tread portion, and a plurality of rows of land portions are defined by the main grooves. In such a pneumatic tire, good drainage performance is achieved by providing a plurality of lug grooves extending in the tire width direction in each land portion of the tread portion.

However, when the number of lug grooves in the tread portion is increased, the rigidity of the tread portion (tread rigidity) is reduced, resulting in a problem of reduced wear resistance and shortened tire life. Conversely, when the number of lug grooves in the tread portion is reduced, the drainage performance deteriorates, and steering stability on wet road surfaces deteriorates. In this way, the wear resistance performance and the steering stability on wet road surfaces are in a trade-off relationship.

Conventionally, in a tire in which main grooves and lug grooves are formed, there is known a tread pattern in which one end of the lug groove is connected to the main groove and the other end is closed within the region of the land portion (see Patent Document 1).

JP 2013-71633 A

In the tire having the above-described conventional tread pattern, drainage performance is ensured to some extent, and a decrease in tread rigidity can be suppressed compared to a tire in which both ends of the lug grooves are connected to the main groove. is insufficient.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a pneumatic tire that can improve wear resistance performance compared to the conventional tire while suppressing deterioration in steering stability performance on wet road surfaces.

One aspect of the present invention is a pneumatic tire. The pneumatic tire is
A tread portion extending in the tire circumferential direction and forming an annular shape and having a tread pattern,
The tread pattern has half tread areas on both sides in the tire width direction with respect to the tire equator line,
a continuous land portion provided in each of the semi-tread regions and continuously making a round in the tire circumferential direction;
an outer circumferential main groove continuously extending in the tire circumferential direction and defining the continuous land portion of each of the semi-tread regions from the tire width direction outer side;
a sipe that extends inward in the tire width direction from each of the outer circumferential main grooves and closes a region of the continuous land portion in the middle;
The sipe includes a sipe main body portion in which the distance between the sipe wall surfaces facing each other on the sipe bottom side in the sipe depth direction is constant, and a sipe wall surface facing each other on the tread surface side of the tread portion of the sipe extending toward the tread surface. a sipe chamfer slanted to open up;
the sipe wall surface of the sipe main body includes an uneven sipe wall surface that is recessed or protrudes in a direction orthogonal to the extension direction of the sipe and the sipe depth direction;
Among the sipe wall surfaces of the sipe chamfered portion, one sipe wall surface has a first chamfer surface having an inclination angle equal to that of the other sipe wall surface in the sipe depth direction, and a second chamfer surface having an inclination angle larger than that of the first chamfer surface. A chamfered surface is provided .

The ratio L2/L1 of the dimension L2 of the sipe chamfered portion in the sipe depth direction to the dimension L1 of the sipe in the sipe depth direction is preferably 15 to 50%.

The sipe wall surface of the sipe body further includes a planar sipe wall surface parallel to the sipe depth direction,
The planar sipe wall surface is provided so as to connect to the sipe chamfered portion on the tread surface side in the sipe depth direction and to the uneven sipe wall surface on the sipe bottom side in the sipe depth direction. is preferred.

A ratio L3/L1 of the dimension L3 of the planar sipe wall surface in the sipe depth direction to the dimension L1 of the sipe in the sipe depth direction is preferably more than 0% and 50% or less.

It is preferable that the extending direction of the sipe is inclined at an angle of 45 degrees or less with respect to the tire width direction.

The angle formed by one sipe wall surface of the sipe chamfered portion and the sipe wall surface of the sipe body portion located on the same side as the sipe wall surface with respect to the center in the sipe width direction is preferably 100 to 170 degrees. .

Another aspect of the present invention is a pneumatic tire. The pneumatic tire is
A pneumatic tire,
A tread portion extending in the tire circumferential direction and forming an annular shape and having a tread pattern,
The tread pattern has half tread areas on both sides in the tire width direction with respect to the tire equator line,
a continuous land portion provided in each of the semi-tread regions and continuously making a round in the tire circumferential direction;
an outer circumferential main groove continuously extending in the tire circumferential direction and defining the continuous land portion of each of the semi-tread regions from the tire width direction outer side;
a sipe that extends inward in the tire width direction from each of the outer circumferential main grooves and closes a region of the continuous land portion in the middle;
The sipe includes a sipe main body portion in which the distance between the sipe wall surfaces facing each other on the sipe bottom side in the sipe depth direction is constant, and a sipe wall surface facing each other on the tread surface side of the tread portion of the sipe extending toward the tread surface. a sipe chamfer slanted to open up;
the sipe wall surface of the sipe main body includes an uneven sipe wall surface that is recessed or protrudes in a direction orthogonal to the extension direction of the sipe and the sipe depth direction;
In the half tread region on the first side in the tire width direction,
The sipe is
an extending portion extending in the tire width direction from one of the pair of outer circumferential main grooves with an extending direction constant or smoothly changing;
a bent portion provided at a closed end portion of the sipe and extending from the extended portion in the tire circumferential direction by bending on the tread surface;
Both the extension portion and the bent portion are characterized by including the sipe chamfered portion and the uneven sipe wall surface.

an edge shape of the bent portion on the tread surface is an arrow shape directed in the extending direction of the extending portion;
The arrow shape is
In a region on one side in the sipe width direction with respect to an arrow direction imaginary line that extends from the center position in the sipe width direction of the connection portion where the extension portion connects to the bent portion toward the tip of the arrow shape, the arrow a first edge extending in the one-side region obliquely with respect to the directional imaginary line;
a second edge having a smaller inclination with respect to the virtual line in the direction of the arrow than the first edge and extending toward the tip;
Furthermore, it is preferable that a region on the other side in the sipe width direction with respect to the virtual line in the direction of the arrow has a third edge extending from the edge of the extension portion toward the tip portion.

In the half tread region on the second side in the tire width direction,
It is preferable that the lengths along the extending direction of the sipe of the sipe wall surfaces of the sipe chamfered portions facing each other across the center position in the sipe width direction are different from each other.

The dimension L1 of the sipe in the sipe depth direction is 5 to 12 mm,
The concave-convex sipe wall surface preferably has a shape in which concave-convex units are repeated in the sipe depth direction, and the number of repetitions of the concave-convex unit is preferably 1.5 to 3.

According to the pneumatic tire described above, it is possible to improve the wear resistance performance as compared with the conventional one while suppressing the deterioration of the steering stability performance on the wet road surface.

1 is a cross-sectional profile view of an example of a pneumatic tire according to an embodiment of the present invention; FIG. FIG. 2 is a developed view showing an example of a tread pattern of the pneumatic tire of the present embodiment; (a), (b) is a top view which expands and shows an example of the 1st sipe shown in FIG. (a), (b) is sectional drawing when an example of the 1st sipe shown to Fig.3 (a) is cut|disconnected along the sipe depth direction. It is sectional drawing when cutting|disconnecting the uneven|corrugated sipe wall surface of the 1st sipe shown in FIG. 2 along an extension direction. It is a perspective view of an example of a 1st sipe when cutting|disconnecting the 1st sipe shown to Fig.3 (a) along a sipe centerline. FIG. 3 is an enlarged plan view showing a main portion of the tread pattern shown in FIG. 2;

The pneumatic tire of this embodiment will be described in detail below. In addition, various embodiments described later are included in the present embodiment.
In this specification, the tire width direction refers to the direction of the central axis of rotation of the pneumatic tire, and the circumferential direction of the tire refers to the direction of rotation of the tread surface when the tire is rotated about the central axis of tire rotation. The term "tire radial direction" refers to a radial direction from the central axis of tire rotation. The outer side in the tire radial direction refers to the side away from the center axis of tire rotation, and the inner side in the tire radial direction refers to the side closer to the center axis of tire rotation. The term "outer side in the tire width direction" refers to the side away from the tire equator in the tire width direction, and the term "inner side in the tire width direction" refers to the side closer to the tire equator in the tire width direction.

FIG. 1 is a profile cross-sectional view of an example of the pneumatic tire of this embodiment. A pneumatic tire T shown in FIG. and a pair of bead portions 3, 3 arranged radially inward of the tire.
A carcass layer 4 is mounted between the pair of bead portions 3,3. The carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction, and is folded back from the tire inner side to the outer side around bead cores 5 arranged in the respective bead portions 3 . A bead filler 6 made of a rubber composition having a triangular cross section is arranged on the outer circumference of the bead core 5 and extends outward in the tire radial direction.

On the other hand, a plurality of belt layers 7 are embedded outside the carcass layer 4 in the tread portion 1 in the tire radial direction. 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 intersect each other between the layers. In the belt layer 7, the inclination angle of the reinforcing cords with respect to the tire circumferential direction is set within a range of 10° to 40°, for example. A steel cord is preferably used as the reinforcing cord for the belt layer 7 . At least one belt cover layer 8 formed by arranging reinforcing cords at an angle of, for example, 5° or less with respect to the tire circumferential direction is arranged on the outer peripheral side of the belt layer 7 for the purpose of improving high-speed durability. there is Organic fiber cords such as nylon and aramid cords are preferably used as the reinforcing cords for the belt cover layer 8 .
The tire internal structure described above is a representative example of a pneumatic tire, but is not limited to this.

FIG. 2 is a developed view showing an example of the tread pattern 10 of the pneumatic tire T of this embodiment. The pneumatic tire T having the tread pattern 10 can be suitably used as a passenger car tire.

In FIG. 2, symbol CL indicates a tire centerline (tire equator line).
The tread pattern 10 mainly includes center main grooves 11 , 12 , shoulder main grooves 13 , 14 , a center continuous land portion 21 , intermediate continuous land portions 22 , 23 , and first sipes 30 , 31 . The tread pattern 10 has half tread areas on both sides (first side and second side) in the tire width direction with respect to the tire centerline CL.

The center main grooves 11 and 12 are provided on both sides in the tire width direction with respect to the center line CL, and circle the tread portion 1 in the tire circumferential direction. The center main groove 12 is provided on the first side and the center main groove 11 is provided on the second side. Edges on both sides of the center main groove 12 are provided with groove chamfered portions 12A and 12B whose chamfered width changes in the tire circumferential direction so as to form a zigzag shape when viewed from the tread surface of the tread portion 1 . At the edges on both sides of the center main groove 12, one groove chamfered portion 12A, 12B gradually increases in chamfer width toward one side in the tire circumferential direction and ends at a predetermined width. At approximately the same position, further chamfered grooves 12A and 12B start, and the chamfered width gradually increases from zero and ends at a predetermined width. The groove chamfered portions 12A and 12B repeat this process to circle the center main groove 12 along the tire circumferential direction. At both edges of the center main groove 12, the chamfer width starts at the same position in the tire circumferential direction and ends at the same position, so the center main groove 12 looks like a zigzag when viewed from the tread surface. However, the groove width of the center main groove 12 is kept constant and the center main groove 12 is circled. In this zigzag shape, at the position where one groove chamfered portion 12A, 12B ends and another grooved chamfered portion 12A, 12B starts, the dimension of the edge step in the tire width direction (the length along the tire width direction) is , 15 to 35% of the groove width of the center main groove 12, for example.
The center main groove 11 is not provided with a chamfered portion like the center main groove 12, and the edges on both sides of the center main groove 11 extend linearly in the tire circumferential direction to circle the tire.

The shoulder main grooves 13 and 14 are provided so as to sandwich the center main grooves 11 and 12 inward in the tire width direction, and extend straight around the tread portion 1 without bending or curving in the tire circumferential direction.
The groove width of the center main grooves 11, 12 and the shoulder main grooves 13, 14 is, for example, 5.0 to 15.0 mm, and the groove depth is 6.5 to 9.0 mm.

The center continuous land portion 21 is formed sandwiched between the center main grooves 11 and 12 and continuously circles in the tire circumferential direction. A center line CL passes over the center continuous land portion 21 .
The intermediate continuous land portion 22 is formed sandwiched between the center main groove 11 and the shoulder main groove 13 and continuously circles the tread portion 1 in the tire circumferential direction outside the center continuous land portion 21 in the tire width direction. The intermediate continuous land portion 23 is also formed sandwiched between the center main groove 12 and the shoulder main groove 14, and continuously circles the tread portion 1 in the tire circumferential direction outside the center continuous land portion 21 in the tire width direction.
No lug grooves are provided in the regions of the center continuous land portion 21 and the intermediate continuous land portions 22 and 23, and only sipes are provided. A lug groove is a groove whose extending direction is closer to the tire width direction than to the tire circumferential direction, and is distinguished from a sipe in terms of dimensions.

The first sipe 30 is provided in the region of the intermediate continuous land portion 23 , extends inward in the tire width direction from the shoulder main groove 14 , and closes within the region of the intermediate continuous land portion 23 without connecting to the center main groove 12 . . The first sipe 31 is provided in the region of the intermediate continuous land portion 22 , extends inward in the tire width direction from the shoulder main groove 13 , and closes within the region of the intermediate continuous land portion 22 without connecting to the center main groove 11 . .

Shoulder land portions 24 and 25 are provided outside the shoulder main grooves 13 and 14 in the tire width direction. In each region of the shoulder land portions 24, 25, the shoulder land portions 24, 25 extend inward in the tire width direction from the tread pattern ends on both sides in the tire width direction and are not connected to the shoulder main grooves 13, 14. A plurality of shoulder lug grooves 35 and 36 are arranged at predetermined intervals in the circumferential direction of the tire to be closed within the region. Shoulder sipes 37, 38 are provided between shoulder lug grooves 35, 36 adjacent in the tire circumferential direction. The shoulder sipes 37 , 38 are provided in parallel with the shoulder lug grooves 35 , 36 inward in the tire width direction from the regions of the shoulder land portions 24 , 25 and are connected to the shoulder main grooves 13 , 14 .

In this way, the tread pattern 10 is continuous in the tire circumferential direction that divides the intermediate continuous land portions 22 and 23 (continuous land portions) and the intermediate continuous land portions 22 and 23 of the respective semi-tread regions from the outside in the tire width direction. Extending shoulder main grooves 13 and 14 (outer circumferential main grooves), and first sipes 30 extending inward in the tire width direction from each of the shoulder main grooves 13 and 14 and closing in the middle of the region of the intermediate continuous land portion (first sipe 30). 1 sipe a) and a first sipe 31 (first sipe b).
As shown in FIG. 2, the first sipes 30, 31 extend from the shoulder main grooves 13, 14 toward the center continuous land portion 21 so as to be inclined in the width direction of the tire. It is provided so as to be closed within the area of 23 .

FIGS. 3A and 3B are plan views showing enlarged examples of the first sipes 30 and 31. FIG. 4(a) and 4(b) are sectional views of an example of the first sipes 30 and 31 shown in FIG. 3(a) taken along the sipe depth direction. FIG. 5 is a cross-sectional view of the after-mentioned uneven sipe wall surface of the first sipe shown in FIG. 2 cut along the extending direction of the sipe (the direction orthogonal to the sipe depth direction). FIG. 6 is a perspective view of an example when the first sipe 30 shown in FIG. 3(a) is cut along the sipe centerline 45 (the line passing through the center of the sipe width of the sipe body portion 40 in FIG. 3(a)). It is a diagram. In addition, in FIG. 6, illustration of the uneven|corrugated sipe wall surface is abbreviate|omitted, and it is represented by the planar-shaped sipe wall surface. FIG. 7 is a plan view showing an enlarged main portion of the tread pattern 10. As shown in FIG.

The first sipes 30 and 31 are composed of a sipe body portion 40 (see FIG. 4A) in which the distance between the sipe wall surfaces facing each other on the sipe bottom side in the depth direction of the first sipes 30 and 31 is constant, and the first sipe and a sipe chamfer 42 inclined so that the sipe wall surfaces facing each other on the side of the tread surface of 30, 31 open toward the tread surface. That is, the first sipes 30 and 31 are so-called chamfered sipes.

In the present embodiment, the sipe wall surface of the sipe main body 40 is recessed or projected in a direction orthogonal to the extending direction of the first sipes 30 and 31 (hereinafter also referred to as the sipe extending direction) and the sipe depth direction. It is a three-dimensional sipe configured so that the sipe main body 40 includes an uneven sipe wall surface 41 (see FIGS. 4(a), 4(b) and 5). Such uneven sipe wall surfaces 41 have unevenness and the distance between the facing sipe wall surfaces is constant. can abut and support each other. For this reason, the sipe wall surface is more effective in suppressing a decrease in tread rigidity than a planar sipe having no irregularities. Specifically, the uneven sipe wall surface 41 has unevenness that is recessed or protrudes in a direction perpendicular to the sipe depth direction, so that the continuous land portions 22 and 23 collapse in the tire circumferential direction during braking and driving. is suppressed. Further, the uneven sipe wall surface 41 has unevenness that is recessed or protruded in a direction orthogonal to the extending direction of the sipe. Falling down is suppressed. In this way, the uneven sipe wall surface 41 has unevenness that is recessed or protrudes in both the direction orthogonal to the sipe depth direction and the direction orthogonal to the sipe extending direction, so that various It is possible to suppress the continuous land portions 22 and 23 from collapsing in the direction, and the effect of suppressing a decrease in tread rigidity is high. Therefore, the wear resistance performance is greatly improved.

According to one embodiment, the concave-convex sipe wall surface 41 has concave-convex units repeated in the sipe depth direction or the sipe extension direction, as in the examples shown in FIGS. preferably. A concave-convex unit means a combination of one concave and one convex adjacent in the sipe depth direction or the sipe extending direction. By arranging the uneven units so as to be repeated in the sipe depth direction or the sipe extending direction, when the continuous land portions 22 and 23 are deformed, the places where the uneven sipe wall surfaces 41 support each other are uniformly dispersed, and the dread is formed. It is highly effective in suppressing a decrease in rigidity. The dimensions in the sipe depth direction and the sipe extension direction of the uneven unit are preferably equal to each other.

4A, 4B, and 5, the unevenness of the uneven sipe wall surface 41 has a recessed or projected shape that curves in the orthogonal direction. Adjacent recesses and protrusions are smoothly connected, but the recesses and protrusions of the recessed and recessed sipe wall surface 41 have a recessed or protruded shape that bends in the orthogonal direction, and the adjacent recesses and protrusions are connected to each other smoothly. It may have a form in which a ridgeline appears on the boundary. Examples of a case where the unevenness of the uneven sipe wall surface 41 has a curved shape include an arc shape along one radius of curvature, a curved shape with a plurality of curvature radii, a curved shape along a sine wave, or any of these. and a shape extending linearly.

4(a), 4(b) and 5, the depth of the recess and the height of the projection of the uneven sipe wall surface 41 change as they advance in the depth direction of the paper surface. , the shape of unevenness at a position in the depth direction different from the plane of the paper (a position shifted by half the unevenness unit from the plane of the paper) is indicated by a dashed line.
In the examples shown in FIGS. 4A, 4B, and 5, the uneven shape of the uneven sipe wall surface 41 is defined by but has a shape that is recessed or protruded on both sides of the sipe width direction, but is recessed on one side in the sipe width direction and is not recessed on the other side, or protrudes on one side in the sipe width direction and the other side It may have a shape that does not protrude into.

According to one embodiment, at both ends of the uneven sipe wall surface 41 in the sipe depth direction, as in the examples shown in FIGS. It is preferable that there is neither a recess nor a protrusion in the sipe width direction. In addition, according to one embodiment, as in the example shown in FIG. , preferably not protruding. In this case, further, according to one embodiment, the first sipes 30 and 31 are planar sipe wall surfaces parallel to the sipe depth, connected to at least one of both ends of the uneven sipe wall surface 41 in the extending direction. may contain

The first sipe 30 (first sipe a) on the first side includes an extending portion 44 and a bent portion 46 when viewed from the tread surface, as shown in FIG. 3(a). The extending portion 44 is a portion extending inward in the tire width direction from the shoulder main groove 14 (outer circumferential main groove) with a constant or smoothly changing (curved) direction. It is a portion that is provided at the closed end portion of the 1 sipe 30 and extends bent from the extension portion 44 in the tire circumferential direction on the tread surface. The sipe main body portion 40 and the sipe chamfered portion 42 are provided on both the extended portion 44 and the bent portion 46 of the first sipe 30 .
On the other hand, the first sipe 31 (first sipe b) on the second side has the end of the extension 44 as the closed end of the first sipe 31 . That is, the first sipe 31 (first sipe b) is not provided with a portion that bends and extends in the tire circumferential direction from the extension portion 44 on the tread surface at the closed end portion.

The first sipe 31 extends from the shoulder main groove 13 in a constant or smoothly changing direction. The inclination angle of the chamfered surface of the sipe chamfered portion 42 with respect to the sipe depth direction does not change and maintains a constant angle.

The depth of the first sipes 30, 31 is preferably 5-12 mm, for example 5.5-8.5 mm. The first sipes 30, 31 are shallower than the center main grooves 11, 12 and the shoulder main grooves 13, 14, and the distance between the sipe wall surfaces in the sipe body 40 is, for example, 0.3 to 0.9 mm. is. Typically, the distance between the sipe walls of a sipe is 0.3-0.9 mm when the sipe walls are parallel. This distance is narrower than the width of the main grooves such as the center main grooves 11 and 12 and the shoulder main grooves 13 and 14 . Sipes and grooves can be distinguished by differences in the distance between parallel sipe walls and the dimensions of the groove width. The groove width is greater than 0.9 mm.
The width of the chamfered surface of the sipe chamfered portion 42 in the extension portion 44 is, for example, 0.6 to 2.0 mm.

In this way, the first sipes 30, 31 are provided in the regions of the intermediate continuous land portions 22, 23, and the first sipes 30, 31 are both closed within the regions of the intermediate continuous land portions 22, 23. A decrease in tread rigidity of the intermediate continuous land portions 22 and 23 is suppressed compared to the lug grooves, and wear resistance performance is improved. Furthermore, since there are no lug grooves in the region of the center continuous land portion 21, a decrease in tread rigidity is suppressed, so wear resistance performance is improved. As described above, since the first sipes 30 and 31 have the uneven sipe wall surface 41, the effect of suppressing the collapse of the continuous land portions 22 and 23 and suppressing the decrease in tread rigidity is high. Greatly improved wear performance. In addition, since both the first sipes 30 and 31 have the uneven sipe wall surface 41, the effect of suppressing the decrease in tread rigidity is exhibited in the half tread regions on both sides, and the wear resistance in the tire width direction is exhibited. Good balance of performance. On the other hand, since the first sipes 30 and 31 provided in the intermediate continuous land portions 22 and 23 are chamfered sipes, the sipe chamfered portion 42 secures a space volume, facilitates the flow of water, and allows the sipe chamfered portion 42 to easily flow. Since the part functions as an edge, steering stability performance on wet road surfaces is improved.
It is generally known to improve tread rigidity in order to ensure wear resistance performance. For that reason, for example, there is a method of reducing the groove area, but if the groove area is reduced, a sufficient space for drainage cannot be secured in the tread portion, and there is a risk that the steering stability on wet roads will deteriorate. In the present embodiment, the first sipes 30 and 31 include both the uneven sipe wall surface 41 and the sipe chamfered portion 42, thereby suppressing deterioration in steering stability on wet road surfaces and improving wear resistance compared to the conventional one. can be compared and improved.

According to one embodiment, the ratio L2/L1 (%) of the dimension L2 of the sipe chamfered portion 42 in the sipe depth direction to the dimension L1 of the first sipes 30 and 31 in the sipe depth direction is 15 to 50%. Preferably. If the ratio L2/L1 is less than 15%, the degree of improvement in steering stability performance on wet road surfaces may be small. There is

According to one embodiment, the sipe wall surface of the sipe main body 40 includes, in addition to the uneven sipe wall surface 41, a planar sipe wall surface 43 parallel to the sipe depth direction. The planar sipe wall surface 43 is preferably provided so as to be connected to the sipe chamfered portion 42 on the tread surface side in the sipe depth direction and to be connected to the uneven sipe wall surface 41 on the sipe bottom side in the sipe depth direction. The space between the facing flat sipe wall surfaces 43 is easier for water to flow smoothly than the space between the facing uneven sipe wall surfaces 41, and the flat sipe wall surfaces 43 are located between the sipe chamfers 42 and the uneven sipe wall surfaces 41. By doing so, it contributes to the improvement of steering stability on wet road surfaces.

Further, according to one embodiment, the ratio L3/L1 (%) of the dimension L3 of the planar sipe wall surface 43 in the sipe depth direction to the dimension L1 of the sipe in the sipe depth direction is more than 0% and 50% or less. is preferably If the ratio L3/L1 exceeds 50%, the area of the concave-convex sipe wall surface 41 is reduced, and the effect of suppressing the decrease in tread rigidity may not be sufficiently obtained.
Note that, according to one embodiment, the sipe body portion 40 may not have the planar sipe wall surface 43 . That is, in the first sipes 30 and 31, the sipe chamfered portion 42 and the uneven sipe wall surface 41 may be connected.

According to one embodiment, the extending direction of the first sipes 30 and 31 (sipe extending direction) is preferably inclined at 45 degrees or less with respect to the tire width direction, as shown in FIG. FIG. 2 shows the angle θ between the sipe extending direction and the tire width direction. The sipe extending direction means the extending direction of the sipe centerline 45 . When the sipe extending direction changes smoothly, the sipe extending direction is the connection position (starting end) of the first sipes 30, 31 with the shoulder main grooves 13, 14 and the closing position of the first sipes 30, 31. It is specified by a straight line connecting the end (terminus). Since the inclination angle of the first sipes 30, 31 with respect to the tire width direction is within the above range, the effect of supporting each other between the uneven sipe wall surfaces 41 during braking and driving is increased, and the continuous land portions 22, 23 are effectively prevented from collapsing. can be suppressed to On the other hand, when the inclination angle of the first sipes 30, 31 with respect to the tire width direction is close to 0°, the continuous land portions 22, 23 tend to collapse during braking and driving, and the effect of suppressing the decrease in tread rigidity is reduced. Therefore, the inclination angle is preferably 5 to 45°, more preferably 20 to 40°. In the example shown in FIG. 2, the inclination angle of the extending direction of the first sipe 30 with respect to the tire width direction is larger than the inclination angle of the extending direction of the first sipe 31 with respect to the tire width direction.

According to one embodiment, one sipe wall surface of the sipe chamfered portion 42 forms an angle α (Fig. 4 (a)) is preferably 100 to 170 degrees. If α does not satisfy the above angle range, a sufficient space for drainage formed by the sipe chamfered portion 42 cannot be secured, and steering stability on wet road surfaces may deteriorate. Further, if α does not satisfy the above angle range, the rigidity of the continuous land portions 22 and 23 defining the sipe chamfered portion 42 may be low, and the effect of suppressing a decrease in tread rigidity may be reduced.

According to one embodiment, the dimension L1 in the sipe depth direction of the first sipes 30 and 31 is 5 to 12 mm, and the uneven sipe wall surface 41 has a shape in which uneven units are repeated in the sipe depth direction. , the number of repetitions of the concave-convex unit is preferably 1.5-3. The length of one uneven unit in the sipe depth direction is represented by P in FIG. 4(a). If the repeating number of the concave-convex unit is less than 1.5, the effect that the concave-convex sipe wall surfaces 41 contact each other and support each other may be insufficient. If the number of repetitions of the concave-convex unit exceeds 3, the surface area of each concave and convex constituting the concave-convex unit is small, and the effect of supporting the concave-convex sipe wall surfaces 41 to each other may be reduced.

Further, according to one embodiment, the uneven sipe wall surface 41 preferably has a shape in which uneven units are repeated in the sipe extending direction. In this case, the length of the uneven unit along the extension direction may be different from or equal to the length of the uneven unit along the sipe depth direction.

According to one embodiment, the edge shape of the bent portion 46 of the first sipe 30 on the tread surface is an arrow shape directed in the extending direction of the extension portion 44 . Specifically, as shown in FIG. 3(a), the arrow shape extends from the center position of the sipe width direction of the connecting portion where the extension portion 44 is connected to the bent portion 46 in the direction of the arrow toward the tip of the arrow shape. A first Equipped with an edge 42F and a second edge 42G, the region (see (a) includes a third edge 42H in the area on the lower right side). The first edge 42F, the second edge 42G, and the third edge 42H are linear.
The first edge 42</b>F is on one side in the sipe width direction with respect to the virtual line in the direction of the arrow that extends from the center position in the sipe width direction of the connecting portion where the extension 44 connects to the bent portion 46 toward the tip of the arrow shape. It extends obliquely with respect to the virtual line in the direction of the arrow in the region (on the upper left side in FIG. 3(a)). The second edge 42G has a smaller inclination with respect to the imaginary line in the direction of the arrow than the first edge 42F and extends toward the tip.
A third edge 42H extends toward the tip so as to extend from the edge of the extension 44 .
Such a shape of the bent portion 46 increases the area of the sipe chamfered portion 42, increases the edge of the bent portion 46, enhances the edge effect, and improves steering stability on wet road surfaces.

Further, according to one embodiment, the chamfered surfaces 42A and 42B of the sipe chamfered portion 42 of the extended portion 44, which face each other across the center position in the sipe width direction, have the same inclination angle. On the other hand, the chamfered surfaces of the sipe chamfered portion 42 of the bent portion 46 have different inclination angles at the portions of the mutually opposed chamfered surfaces. For example, the inclination angle of the chamfered surface 42C shown in FIG. 4B is made larger than the inclination angle of the chamfered surface 42B. In this way, by varying the inclination angle of the chamfered surface in the bent portion 46, the spatial volume of the sipe chamfered portion 42 can be adjusted according to the edge shape of the bent portion 46. can be increased, and steering stability performance on wet road surfaces is improved.

According to one embodiment, the sipe body portion 40 extends toward the arrow-shaped tip and chamfers the sipe chamfer 42 on the side of the bend 46 having the first edge 42F and the second edge 42G. The surface has a chamfered surface 42A (first chamfered surface) extending from the chamfered surface 42A in the extension portion 44, and a chamfered inclination angle different from that of the chamfered surface 42A. and a chamfered surface 42C (second chamfered surface) which is a plane connecting and passing through the first edge 42F located on the tread surface. A chamfered surface 42A of the chamfered portion on the side of the bent portion 46 having the third edge 42H is a surface (flat surface) obtained by extending the chamfered surface 42A of the extension portion 44 .
Thus, since the chamfered surface 42C is an inclined surface connected to the tread surface at the first edge 42F, it is possible to maintain high tread rigidity in the region of the land portion near the first edge 42F. , the wear resistance performance is improved.

According to one embodiment, the ridgeline 42E, which is the connecting portion of the chamfered surfaces 42A and 42C, passes through the point where the sipe body 40 and the chamfered surface 42A connect at the distal end. In this way, the chamfered surface 42C becomes an inclined surface and extends to the connecting portion of the chamfered surfaces 42A and 42C at the tip, so that the sipe chamfered portion 42 can secure a space for drainage. As a result, steering stability performance on wet road surfaces is improved.
At this time, according to one embodiment, the chamfered width of the chamfered surface 42A and the chamfered width of the chamfered surface 42C can be narrowed toward the distal end in accordance with the shape of the arrow, so that the effect of the chamfered sipe can be obtained at the distal end. can be gradually reduced toward
Also according to one embodiment, the bend 46 includes a planar wall surface 42D passing through the second edge 42G and connecting with the chamfer 42C. The wall surface 42</b>D extends in the sipe depth direction at an inclination angle directed toward the tire radial direction compared to the inclination of the chamfered surfaces 42</b>A and 42</b>C of the sipe chamfered portion 42 . Therefore, since the second edge 42G is located on the steep wall surface 42D, the edge effect can be enhanced. The inclination angle of the wall surface 42D with respect to the tread surface is, for example, 80 to 110 degrees, and 85 to 95 degrees. That is, the wall surface 42D extends substantially parallel to the tire radial direction.

According to one embodiment, the closed end portion of the first sipe 31 (first sipe b) is inclined toward the tire radial direction compared to the inclination of the chamfered surfaces 42A and 42B of the sipe chamfered portion 42, and the sipe depth It has a planar wall surface 42I (see FIG. 3(b)) connected to the chamfered surfaces 42A and 42B extending in the direction. Thus, the first sipe 31 without the bent portion 46 is closed by the wall surface 42I. As shown in FIG. 3B, the wall surface 42I is preferably provided in an asymmetrical shape with respect to the sipe center line like a sword shape. That is, the lengths L42A and L42B (see FIG. 2) along the sipe extending direction of the chamfered surfaces 42A and 42B (sipe wall surfaces) of the sipe chamfered portion 42 facing each other across the center position in the sipe width direction are different from each other. is preferred. In the example shown in FIG. 2, the length L42A of the chamfered surface 42A is shorter than the length L42B of the chamfered surface 42B. Since the chamfered surfaces 42A and 42B have different lengths, the effect of the sipe chamfered portion 42 can be gradually reduced at the closed end. The inclination angle of the wall surface 42I with respect to the tread surface is, for example, 80 to 110 degrees, and 85 to 95 degrees. That is, the wall surface 41I extends substantially parallel to the tire radial direction.

In the tread pattern 10, as shown in FIG. 2, in the regions of the center continuous land portion 21 and the intermediate continuous land portions 22 and 23, which are defined by the two center main grooves 11 and 12 (inner circumferential direction main grooves), No lug grooves are provided, and out of the center main grooves 11 and 12, the edges on both sides of the center main groove 12 on the first side have a chamfered width so that they form a zigzag shape when viewed from the tread surface of the tread portion. It has groove chamfers 12A and 12B that change in the circumferential direction. The groove area ratio of the tread pattern 10 is different between the first side half tread area and the second side half tread area, and the groove area ratio of the first side half tread area is the second side half tread area. is smaller than the groove area ratio of the half tread region on the side of Therefore, the steering stability performance on wet road surfaces in the semi-tread area on the first side tends to be insufficient compared to the semi-tread area on the second side. This insufficient portion can be compensated for by the edge effect of the zigzag shape of the center main groove 12 and the edge effect and drainage performance of the bent portion 46 of the first sipe 30 . Moreover, since lug grooves are not provided in the regions of the center continuous land portion 21 and the intermediate continuous land portions 22, 23, the tread rigidity of the center continuous land portion 21 and the intermediate continuous land portions 22, 23 is not lowered.

As shown in FIG. 2 or FIG. 7, in the region of the intermediate continuous land portion 23 (intermediate continuous land portion α) on the first side, narrow grooves 60 that do not communicate with the bent portion 46 are formed intermittently in the tire circumferential direction. is provided in The extending direction of the narrow groove 60 is parallel to the extending direction of the second edge 42G of the bent portion 46 on the center continuous land portion 21 side. Since the edge of the second edge 42G and the edge of the groove 60 can be made parallel to each other and the directions of the edge components can be aligned, the edge effect is enhanced. Therefore, steering stability performance on wet road surfaces can be improved.

It is preferable that the pneumatic tire T is oriented with respect to the vehicle such that the first side is located on the outside of the vehicle. The designation of the mounting orientation is attached as information to the sidewall surface of the pneumatic tire T using characters, symbols, or the like. As a result, in the semi-tread region on the first side outside the cornering where a high load is applied during cornering and greatly affects the steering stability performance, the zigzag shape of the pneumatic tire T is positioned on the vehicle outer side with respect to the center line CL. The shape of the center main groove 12, the first sipe 30, and the edges of the narrow grooves 60 further improve steering stability on wet road surfaces.

As shown in FIG. 2, in the region of the intermediate continuous land portion 22 (intermediate continuous land portion β) on the second side, the groove extends from the center main groove 11 (inner circumferential main groove) and communicates with the outer circumferential main groove. A second sipe 32 is provided that closes off without squeezing. In addition, in the area of the center continuous land portion 21, the center main groove extends from the center main groove 11 (inner circumferential direction main groove) in contact with the intermediate continuous land portion 22 on the second side toward the center main groove 12. A third sipe 33 is provided that closes without communicating with 12 . At this time, the direction of inclination of the second sipe 32 and the third sipe 33 with respect to the tire width direction and the position on the tire circumference are set so that the second sipe 32 is positioned on the extension line of the third sipe 33 . is preferred. As a result, the second sipe 32 and the third sipe 33 act like one sipe, concentrating the edge effect, so that the braking/driving performance on wet road surfaces can be improved. The 2nd sipe 32 and the 3rd sipe 33 are sipes having a configuration in which opposing sipe wall surfaces are parallel at any position in the sipe depth direction.

The first sipe 31 (first sipe b) and the second sipe 32 provided in the region of the intermediate continuous land portion 31 are arranged in the tire circumferential direction with respect to the same side in the tire width direction when viewed from the tread surface. are slanted on different sides of the That is, the first sipe 31 and the second sipe 32 form an inverted V shape. As a result, whether the pneumatic tire T has a positive slip angle or a negative slip angle, it is possible to effectively exhibit steering stability performance and braking/driving performance on wet road surfaces.

The first sipes 30 and 31 are inclined to the same side in the tire circumferential direction with respect to the same side in the tire width direction as viewed from the tread surface. In the example shown in FIG. 2, the first sipes 30 and 31 extend from the lower left to the upper right direction or from the upper right direction to the lower left direction on the paper surface. The inclination angle of the extending direction of the extending portion 44 of the first sipes 30, 31 with respect to the tire circumferential direction is preferably 25 to 75 degrees. If the inclination angle is less than 25 degrees, the tread rigidity of the intermediate continuous land portion 23 is locally reduced in the vicinity of the connecting portions where the first sipes 30, 31 connect with the shoulder main grooves 13, 14, resulting in stable steering on dry road surfaces. The performance tends to deteriorate, and it tends to become the nucleus for the occurrence of uneven wear. If the inclination angle is larger than 75 degrees, the tread rigidity in the tire circumferential direction of the intermediate continuous land portion 23 is lowered, and the steering stability performance on dry road surfaces is likely to be lowered.

As shown in FIG. 2 , the region of the shoulder land portion 24 is provided with a circumferential auxiliary groove 39 and a shoulder lug groove 36 . The shoulder lug groove 36 extends in the tire width direction from the outside in the tire width direction and closes without communicating with the shoulder main groove 13 . At this time, the shoulder lug grooves 36 preferably intersect the circumferential auxiliary grooves 39 . The circumferential auxiliary groove 39 prevents the tread rigidity of the shoulder land portion 24 from becoming too high, and adjusts the contact area of the shoulder land portion 24 . In particular, when the shoulder land portion 24 is mounted on the vehicle so that it faces the inside of the vehicle, the camber effect (negative camber) increases the contact area of the tire and reduces the contact pressure. wear can be suppressed.
The groove width of the circumferential auxiliary groove 39 is, for example, 0.8 to 3.0 mm, and the groove depth is 1.0 to 4.5 mm.

In order to further improve the steering stability performance on wet road surfaces, the inclination angle θ of the chamfered surfaces 42A and 42B of the first sipes 30 and 31 with respect to the sipe depth direction (see FIGS. 4A and 4B) is, for example, It is preferably 20 to 80 degrees. In the first sipes 30 and 31 , the length of the sipe chamfered portion 42 in the sipe depth direction is preferably constant regardless of the position in the extending direction of the first sipes 30 and 31 . Therefore, in the first sipes 30 and 31, the position of the connecting position between the sipe chamfered portion 42 and the sipe body portion 40 in the sipe depth direction as viewed from the tread surface corresponds to the position in the extending direction of the first sipes 30 and 31. It is preferably constant regardless of the

(Experimental example)
In order to confirm the effect of the pneumatic tire T of the embodiment, prototype pneumatic tires having various tread patterns were produced and their performance was evaluated. Specifically, the tire size of the prototype pneumatic tire was 225/50R17 98W. A prototype pneumatic tire was mounted on a rim (rim size 17×7.5J) and mounted on a test vehicle (4WD vehicle with a displacement of 2000 cc) under the condition of air pressure of 230 kPa. The test vehicle was run on the test course road surface to evaluate the wear resistance performance and steering stability performance on the wet road surface.

In the evaluation of wear resistance performance, the test tire was mounted on the above test vehicle and subjected to pattern running of 12000 km on a test course including a turning track. After the test, the groove depths of the center main grooves 11 and 12 were measured, and the reduction amount (height) of the tread rubber was calculated. The evaluation results are shown as indices with the conventional example being 100, using the reciprocal of the calculated value. A larger index means less tread rubber loss and better wear resistance.
In the evaluation of steering stability performance (wet performance) on wet road surfaces, the running time was measured when driving over a predetermined range on a wet road surface that reproduced rainy weather conditions, and the reciprocal of the time was indexed. An index of 100 was used as the reciprocal of the running time measured in the conventional example. Therefore, a higher index indicates higher performance.

A prototype pneumatic tire T used the tire structure shown in FIG. In the tread pattern of the pneumatic tire of the conventional example, the first sipes 30 and 31 are absent and lug grooves are used. The groove width of the lug groove was set to 4.6 mm.
In Comparative Example 1, the first sipes 30 and 31 are sipes (non chamfered sipe).
In Comparative Example 2, the first sipes 30 and 31 are the sipes of Comparative Example 1 as the sipe main body portion and further include a sipe chamfered portion 42 .
In Comparative Example 3, in the three-dimensional sipe shown in FIG. A sipe having a body portion and a sipe chamfered portion 42 is used.
In Comparative Example 4, in Comparative Example 1, the opposing sipe wall surface was replaced with a flat sipe wall surface, and an uneven sipe wall surface was used.
As for the distance of the sipe wall surface, the distance of the sipe main body portion 40 in each of Examples and Comparative Examples 1 to 4 described below was set to be the same. The sipe depth of the first sipes 30 and 31 was set to 5.7 mm, and the distance between the sipe wall surfaces in the sipe body portion 40 was set to 0.6 mm. In the example having the bent portion 46, the maximum distance between the facing sipe wall surfaces in the sipe chamfered portion 42 was set to 5.5 mm.
The three-dimensional sipes employed in the examples were based on the forms shown in FIGS.

Tables 1 to 3 below show each specification and its evaluation results.
The column of "shape" in Tables 1 to 3 below indicates whether the continuous land portion is provided with a lug groove or a sipe, and if it is a sipe, indicates the shape of the sipe. "Two-dimensional" means the two-dimensional sipe, and "three-dimensional" means the three-dimensional sipe.
In the table, "θ" indicates the angle formed by the extending direction of the sipe and the tire width direction. "α" indicates the angle formed by the sipe wall surface of the sipe chamfered surface and the sipe wall surface of the sipe main body.
In the half tread regions on both sides, the shapes of the closed ends of the first sipes 30 and 31 are arrow-shaped in Example 10, sword-shaped in Example 11, and one half-tread in Example 12. An arrow shape was used in the region, and a sword shape was used in the other half tread region. Further, in Examples 1 to 9, in the half tread regions on both sides, the two chamfered surfaces 42A and 42B sandwiching the center position of the sipe width had the same length in the extending direction.
When the index of wear resistance performance is 104 or more, the index of wet performance is 97 or more, and the sum of the indices of wear resistance performance and wet performance is 203 or more, deterioration of wet performance is suppressed, and wear resistance performance is improved. was evaluated as being able to be improved compared to the conventional method.

By comparing the conventional example, the comparative example, and the working example, it was found that by providing sipes composed of uneven sipe wall surfaces and sipe chamfered portions in the continuous land portions on both sides in the tire width direction, wear resistance was improved while suppressing deterioration in wet performance. is improved compared to the conventional method.

Although not shown in the table, in Example 1, only one of the two continuous land portions 22 and 23 is provided with a sipe having an uneven sipe wall surface and a sipe chamfered portion, and the other continuous land portion In the comparative example provided with a sipe composed of an uneven sipe wall surface, the wet performance was insufficient.

Although the pneumatic tire of the present invention has been described in detail above, the present invention is not limited to the above embodiments and examples, and various improvements and modifications may be made without departing from the gist of the present invention. Of course.

1 tread portion 2 sidewall portion 3 bead portion 4 carcass layer 5 bead core 6 bead filler 7 belt layer 8 belt cover layer 10 tread patterns 11, 12 center main grooves 13, 14 shoulder main groove 21 center continuous land portions 22, 23 intermediate continuous Land portions 24, 25 Shoulder land portions 30, 31 First sipe 32 Second sipe 33 Third sipe 35, 36 Shoulder lug grooves 37, 38 Shoulder sipe 39 Circumferential auxiliary groove 40 Sipe body portion 42 Sipe chamfered portions 42A, 42B, 42C Chamfered surface 42D Wall surface 42E Ridge line 42F First edge 42G Second edge
42H Third edge 42I Wall surface 45 Sipe centerline 60 Thin groove

Claims (10)

A pneumatic tire,
A tread portion extending in the tire circumferential direction and forming an annular shape and having a tread pattern,
The tread pattern has half tread areas on both sides in the tire width direction with respect to the tire equator line,
a continuous land portion provided in each of the semi-tread regions and continuously making a round in the tire circumferential direction;
an outer circumferential main groove continuously extending in the tire circumferential direction and defining the continuous land portion of each of the semi-tread regions from the tire width direction outer side;
a sipe that extends inward in the tire width direction from each of the outer circumferential main grooves and closes a region of the continuous land portion in the middle;
The sipe includes a sipe main body portion in which the distance between the sipe wall surfaces facing each other on the sipe bottom side in the sipe depth direction is constant, and a sipe wall surface facing each other on the tread surface side of the tread portion of the sipe extending toward the tread surface. a sipe chamfer slanted to open up;
the sipe wall surface of the sipe main body includes an uneven sipe wall surface that is recessed or protrudes in a direction orthogonal to the extension direction of the sipe and the sipe depth direction;
Among the sipe wall surfaces of the sipe chamfered portion, one sipe wall surface has a first chamfer surface having an inclination angle equal to that of the other sipe wall surface in the sipe depth direction, and a second chamfer surface having an inclination angle larger than that of the first chamfer surface. A pneumatic tire comprising: a chamfered surface ; The pneumatic tire according to claim 1, wherein a ratio L2/L1 of the dimension L2 of the sipe chamfered portion in the sipe depth direction to the dimension L1 of the sipe in the sipe depth direction is 15 to 50%. The sipe wall surface of the sipe body further includes a planar sipe wall surface parallel to the sipe depth direction,
The planar sipe wall surface is provided so as to connect to the sipe chamfered portion on the tread surface side in the sipe depth direction and to the uneven sipe wall surface on the sipe bottom side in the sipe depth direction. , The pneumatic tire according to claim 1 or 2. The ratio L3/L1 of the dimension L3 of the planar sipe wall surface in the sipe depth direction to the dimension L1 of the sipe in the sipe depth direction is more than 0% and 50% or less according to claim 3. pneumatic tires. The pneumatic tire according to any one of claims 1 to 4, wherein the extending direction of the sipe is inclined at an angle of 45 degrees or less with respect to the tire width direction. The angle formed by one sipe wall surface of the sipe chamfered portion and the sipe wall surface of the sipe body portion located on the same side as the sipe wall surface with respect to the center in the sipe width direction is 100 to 170 degrees. 6. The pneumatic tire according to any one of 1 to 5. A pneumatic tire,
A tread portion extending in the tire circumferential direction and forming an annular shape and having a tread pattern,
The tread pattern has half tread areas on both sides in the tire width direction with respect to the tire equator line,
a continuous land portion provided in each of the semi-tread regions and continuously making a round in the tire circumferential direction;
an outer circumferential main groove continuously extending in the tire circumferential direction and defining the continuous land portion of each of the semi-tread regions from the tire width direction outer side;
a sipe that extends inward in the tire width direction from each of the outer circumferential main grooves and closes a region of the continuous land portion in the middle;
The sipe includes a sipe main body portion in which the distance between the sipe wall surfaces facing each other on the sipe bottom side in the sipe depth direction is constant, and a sipe wall surface facing each other on the tread surface side of the tread portion of the sipe extending toward the tread surface. a sipe chamfer slanted to open up;
the sipe wall surface of the sipe main body includes an uneven sipe wall surface that is recessed or protrudes in a direction orthogonal to the extension direction of the sipe and the sipe depth direction;
In the half tread region on the first side in the tire width direction,
The sipe is
an extending portion extending in the tire width direction from one of the pair of outer circumferential main grooves with an extending direction constant or smoothly changing;
a bent portion provided at a closed end portion of the sipe and extending from the extended portion in the tire circumferential direction by bending on the tread surface;
A pneumatic tire, wherein both the extending portion and the bending portion are provided with the sipe chamfered portion and the uneven sipe wall surface. an edge shape of the bent portion on the tread surface is an arrow shape directed in the extending direction of the extending portion;
The arrow shape is
In a region on one side in the sipe width direction with respect to an arrow direction imaginary line that extends from the center position in the sipe width direction of the connection portion where the extension portion connects to the bent portion toward the tip of the arrow shape, the arrow a first edge extending in the one-side region obliquely with respect to the directional imaginary line;
a second edge having a smaller inclination with respect to the virtual line in the direction of the arrow than the first edge and extending toward the tip;
Further, in a region on the other side in the sipe width direction with respect to the virtual line in the direction of the arrow, a third edge is provided so as to extend from the edge of the extension portion toward the tip portion. The pneumatic tire described in . In the half tread region on the second side in the tire width direction,
The pneumatic pneumatic according to any one of claims 1 to 8, wherein the lengths along the extending direction of the sipe of the sipe wall surfaces of the sipe chamfered portions facing each other across the center position in the sipe width direction are different from each other. tire. The dimension L1 of the sipe in the sipe depth direction is 5 to 12 mm,
The uneven sipe wall surface according to any one of claims 1 to 9, wherein the uneven sipe wall surface has a shape in which uneven units are repeated in the sipe depth direction, and the number of repetitions of the uneven unit is 1.5 to 3. Pneumatic tires as described.

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