JP2008030621A - Tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire capable of suppressing a change in the rigidity of a land part even when the input direction of a force from a road surface is changed. <P>SOLUTION: In the tire 1, one or more sipes 3 are formed in every block 23-25, which are a plurality of land parts. In one wall surface 3a of both opposed wall surfaces constituting each sipe 3, one or more protrusions 31, in which the amount of protrusion relative to this one wall surface 3a is increased in the one-way sipe depth direction, are formed, and an edge 31c is formed between an inclined surface 31a and a peripheral surface 31b constituting this protrusion 31. This edge 31c is a circular arc protruded in the sipe depth direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tire, and more particularly to a tire in which a sipe is formed in a land portion of a tread portion.

  Conventionally, some tires, particularly studless tires, have a sipe formed on a land portion of a tread portion in order to improve ice and snow performance. This sipe is composed of opposing wall surfaces formed inside the land portion. For example, as shown in Patent Document 1, a plurality of protrusions that protrude in the tire width direction or the tire circumferential direction are formed on one wall surface of both wall surfaces constituting a conventional sipe. There is something. That is, there is one in which a plurality of depressions corresponding to a plurality of protrusions are formed on the other wall surface of the both wall surfaces constituting the conventional sipe.

  In the studless tire in which the conventional sipe is formed in the land portion, when the force is applied to the land portion in the direction in which the one wall surface protrudes, the land portion can be prevented from falling down. Therefore, in a studless tire in which a conventional sipe is formed in a land portion, a change in rigidity of the land portion when a force in the tire width direction or the tire circumferential direction is applied to the land portion can be suppressed. Thereby, it is possible to improve the handling stability as well as the snow and ice performance.

JP 2000-177329 A

  However, conventional sipe shapes include a planar shape (see “Conventional Example 1” in Table 1) in which the shape of the protrusion extends in the tire width direction or the tire circumferential direction, and a plurality of polygonal pyramid shapes (Table 1 “Conventional Example”). 2 ”). Therefore, in a studless tire with a conventional sipe formed on the land, it is difficult to suppress changes in rigidity of the land when the force transmitted from the road surface to the land, that is, the input direction of the force from the road surface changes. there were. That is, it has been difficult to further improve the snow and snow performance and the handling stability.

  This invention is made in view of the above, Comprising: It aims at providing the tire which can suppress the rigidity change of a land part, even if the input direction of the force from a road surface changes.

  In order to solve the above-described problems and achieve the object, in the tire according to the present invention, at least one or more sipes are formed in the land portion of the tread portion composed of a plurality of groove portions and a plurality of land portions. 1, one or more of the projecting portions in which the projecting amount with respect to the one wall surface is increased in one direction is formed on one of the opposing wall surfaces constituting the sipe, and the slope constituting the projecting portion An edge is formed between the surface and the outer peripheral surface, and the edge is at least one of an arc or an elliptical arc protruding in the one direction.

  According to the present invention, the plurality of protrusions formed on one wall surface are formed such that the edge of the arc or elliptical arc protrudes in one direction, and the recesses corresponding to the plurality of protrusions are formed on the other wall surface, respectively. Is done. Therefore, even if a force in the tire width direction or the tire circumferential direction is applied to the land portion, one wall surface on which a plurality of protrusions are formed and the other on which a plurality of depressions corresponding to the respective protrusions are formed Therefore, the change in rigidity of the land portion when a force in the tire width direction or the tire circumferential direction is applied to the land portion can be suppressed.

  Moreover, since the edge of each protrusion is a circular arc or an elliptical arc, it has a plurality of normal directions. That is, each protrusion has an edge component perpendicular to each normal direction for each normal direction. Therefore, even if the force transmitted from the road surface to the land, that is, the input direction of the force from the road surface changes, the input direction of the force from the road surface becomes the same direction as any one of the plurality of normal directions of the edge. In addition, it is possible to maintain the catch between the protrusions due to the edge components of the protrusions and the recesses corresponding to the protrusions. Thereby, even if the input direction of the force from a road surface changes, the rigidity change of a land part can be suppressed.

  In the tire, it is preferable that the protruding portion is formed continuously in at least one of the one direction or the orthogonal direction orthogonal to the one direction.

  In the tire, it is preferable that at least one of the ends of the edges of the protrusions adjacent in the orthogonal direction is connected to each other.

  In the tire, it is preferable that at least one of the ends of the edge is connected to the outer peripheral surface of the protruding portion adjacent in the one direction.

  In the tire, the one direction is preferably a sipe depth direction.

  In the tire, the one direction in the center-side protruding portion located in the tire center region of the tread portion is the sipe depth direction, and the shoulder-side protruding portion located in the tire shoulder region of the tread portion. The one direction in is preferably different from the one direction in the center-side protruding portion.

  In the tire, the one direction in the shoulder-side protrusion is a direction from the tire shoulder region toward the tire center region, and the one direction in the shoulder-side protrusion and the center-side protrusion. It is preferable that an angle formed by the one direction in the portion is 45 degrees or less.

  In addition, in the tire described above, of the sipe formed for each land portion, one or more sipe is one or more of the other sipe, and the protrusions of the protrusions in the one sipe It is preferable that the forming direction and the projecting direction of the projecting portions of the other sipes are opposed to each other.

  In the tire, it is preferable that the protrusions differ in at least one of the maximum protrusion amount of the protrusions and the maximum length of both ends in the one direction of the inclined surface of the protrusions. .

  In the tire, the maximum protrusion amount of each protrusion is preferably 0.1 mm or more and 5.0 mm or less.

  In the tire, it is preferable that the maximum length of both ends in the one direction of the inclined surface of each protrusion is 0.3 mm or more and 10 mm or less.

  The tire according to the present invention has an effect that the change in rigidity of the land portion can be suppressed even if the input direction of the force from the road surface changes because the edge of each protruding portion has a plurality of normal directions. .

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following examples. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same. Here, the tire is mounted on a vehicle, but includes not only a tire mounted on a passenger car or the like but also a heavy load tire mounted on a truck, a bus or the like. Further, in the following embodiment, a tire whose land portion is composed only of blocks will be described, but the present invention is not limited thereto, and a tire whose land portion is composed of blocks and ribs, You may use for the tire from which the land part was comprised only with the rib.

  FIG. 1 is a diagram showing a configuration example of a tire according to the present invention. FIG. 2 is an enlarged view of a main part of each block. FIG. 3 is a diagram showing one wall surface constituting the sipe. 4 is a cross-sectional view taken along the line CC of FIG. FIG. 5 is an enlarged view of part D of FIG.

  As shown in FIG. 1, a tire 1 according to the present invention has a tread portion 2. The tread portion 2 includes a plurality of groove portions and a plurality of land portions defined by the groove portions. The plurality of groove portions include a plurality of circumferential grooves 21 that are continuous in the tire circumferential direction and a plurality of lug grooves 22 that are continuous in the tire width direction and at least one end of which communicates with the circumferential groove 21. The plurality of land portions include a plurality of center blocks 23 defined by the circumferential grooves 21 and lug grooves 22 in the tire center portion, and a plurality of right shoulders defined by the circumferential grooves 21 and lug grooves 22 in the right tire shoulder portion. The block 24 and a plurality of left shoulder blocks 25 defined by the circumferential grooves 21 and lug grooves 22 in the left tire shoulder portion.

  A plurality of sipes 3 are formed in each land portion, that is, the center block 23 and the left and right shoulder blocks 24 and 25 (hereinafter simply referred to as “each block 23 to 25”). Each sipe 3 is formed from the block surfaces 23a, 24a, 25a of the blocks 23 to 25 toward the inside in the tire radial direction, that is, toward the sipe depth direction. Moreover, each sipe 3 is extended and formed in the tire width direction, and is opened to both the block wall surfaces in the tire width direction of each block 23-25. The plurality of sipes 3 formed in the respective blocks 23 to 25 are formed so as to be adjacent to each other in the tire circumferential direction.

  Each sipe 3 is composed of opposing wall surfaces 3a and 3b. A plurality of protruding portions 31 are formed on one wall surface 3a of the opposing wall surfaces 3a and 3b. Each protrusion 31 protrudes toward the other wall surface 3b. Moreover, the protrusion amount with respect to this one wall surface 3a of each protrusion part 31 is formed increasing toward the sipe depth direction. Thereby, each protrusion 31 has an inclined surface 31a that is gently inclined toward the other wall surface 3b in the sipe depth direction, and an outer peripheral surface that is abruptly inclined toward the one wall surface 3a in the sipe depth direction. 31b. Each protrusion 31 has an edge 31c formed between the inclined surface 31a and the outer peripheral surface 31b. The edge 31c of each protrusion 31 is formed in a circular arc protruding in the sipe depth direction in this embodiment, which protrudes in the sipe depth direction which is one direction. Although not shown, each sipe 3 formed in each block 23 to 25 has the same direction (in this embodiment, one of the tire circumferential directions) in which each protrusion 31 protrudes in each sipe 3. It is arranged to be.

  Here, as shown in FIG. 4, the maximum protrusion amount H of each protrusion 31 is preferably 0.1 mm or more and 5.0 mm or less. Furthermore, it is preferable that it is 1.0 mm or more and 3.0 mm or less. If the maximum protrusion amount H is set to 0.1 mm or less, if the sipe molding die for forming the sipe 3 is less than 0.1 mm, the recesses and depressions 32 to which the protrusions 31 are transferred are transferred. This is because it becomes difficult to process the convex portions. Further, the reason why the maximum protrusion amount H is set to 5.0 mm or less is that when it exceeds 5.0 mm, a manufacturing failure is likely to occur.

  Moreover, it is preferable that the maximum length W of the both ends in one direction of each protrusion part 31 is 0.3 mm or more and 10 mm or less. Furthermore, it is preferable that it is 2.0 mm or more and 5.0 mm or less. If the maximum length W is set to 0.3 mm or more, if the length W is less than 0.3 mm, the concave portion and the concave portion 32 to which the protruding portion 31 is transferred are transferred to the sipe molding die for molding the sipe 3. This is because it becomes difficult to process the convex portions. Further, the reason why the maximum length W is set to 10 mm or less is that when it exceeds 10 mm, each sipe 3 becomes deep and the block rigidity of each of the blocks 23 to 25 decreases. In this embodiment, the maximum protrusion amount H and the maximum length W of the protrusions 31 in the plurality of sipes 3 formed in the blocks 23 to 25 are substantially the same.

  2-5, the protrusion part 31 is continuously formed in each sipe 3 in the sipe depth direction which is one direction, and the tire width direction which is an orthogonal direction orthogonal to one direction. Of the protrusions 31 in each sipe 3, the protrusions 31 adjacent in the tire width direction are connected to each other at least one of the ends 31d and 31e of the edge 31c. In this embodiment, one end 31d of the edge 31c of each protrusion 31 is connected to the other end 31e of the edge 31c of the protrusion 31 adjacent in the tire width direction, and the other end 31e of the edge 31c of each protrusion 31 is the tire width. It connects with the end 31d of the edge 31c of the protrusion part 31 adjacent to a direction. Of the protrusions 31 in each sipe 3, the protrusions 31 adjacent to each other in the sipe depth direction are connected to the outer peripheral surface 31b at least one of the ends 31d and 31e of the edge 31c. In this embodiment, one end 31d of the edge 31c of the protruding portion 31 adjacent in the sipe depth direction is connected to the substantially central portion in the tire width direction of the outer peripheral surface 31b of each protruding portion 31, and this one end 31d is connected. The other end 31e of the edge 31c of the protruding part 31 adjacent to the protruding part 31 in the tire width direction is connected. That is, in the plurality of protrusions 31 in each sipe 3, each protrusion 31 continues in the tire width direction, and the pitch in the tire width direction of each protrusion 31 in the sipe depth direction continues with a half-pitch shift. In this embodiment, the arcs of the edges 31c of the protrusions 31 are continuous in the tire width direction and are shifted by a radius in the sipe depth direction. Thereby, on one wall surface 3a of each sipe 3, as shown in FIG. 3, the protruding scale-like pattern visually recognized like a fish scale is formed by the plurality of formed protruding portions 31.

  Here, of the opposing wall surfaces 3 a and 3 b constituting the sipe 3, the other wall surface 3 b is formed with a plurality of recess portions 32 respectively facing the protruding portions 31 in the sipe 3. Each recess 32 is recessed in a direction opposite to the direction in which each protrusion 31 protrudes (in this embodiment, one of the tire circumferential directions) so that a gap d is formed between each protrusion 31. Is formed. Each recess 32 is composed of an inclined surface 32a that faces the inclined surface 31a of each protrusion 31 and an outer peripheral surface 32b that faces the outer peripheral surface 31b. Further, each recess 32 has an edge 32c formed between the inclined surface 32a and the outer peripheral surface 32b. The edge 32c of each recess 32 is formed in an arc that protrudes in the sipe depth direction, like the edge 31c of each protrusion 31 described above. Thereby, although illustration is abbreviate | omitted also to the other wall surface 3b of each sipe 3, the hollow scale-like pattern visually recognized like a fish scale is formed by the formed several hollow part 32. FIG.

  That is, a plurality of protrusions 31 formed on one wall surface 3a are formed, and a plurality of depressions 32 respectively corresponding to the plurality of protrusions 31 are formed on the other wall surface 3b. Therefore, even if the tire circumferential direction force A shown in FIG. 2 or the tire width direction force B shown in FIG. 3 is applied to the blocks 23 to 25 which are the land portions, the protrusions 31 and the protrusions 31 are provided. Since each depression 32 facing each other supports each other, that is, one wall 3a on which the plurality of protrusions 31 are formed and the other wall 3b on which the plurality of depressions 32 are formed support each other, When these forces A and B are applied to the blocks 23 to 25, the change in rigidity of the blocks 23 to 25 can be suppressed.

  As shown in FIG. 5, the edge 31 c of each protruding portion 31 has a plurality of normal directions E because each edge 31 c is an arc protruding in the sipe depth direction which is one direction. Therefore, each protrusion 31 has an edge component perpendicular to each normal direction E for each normal direction E. Here, even if the force transmitted from the road surface (not shown) to the blocks 23 to 25 which are land portions, that is, the force from the road surface is the sipe depth direction F, the input direction G is different from the sipe depth direction F. Even if it changes, it becomes the same direction as any one of the plurality of normal directions E of the edge 31c. Maintaining the catch between each protrusion 31 and each recess 32 corresponding to each protrusion 31 by the edge component of each protrusion 31, for example, each protrusion 31 and each recess 32 corresponding to each protrusion 31 Relative movement can be suppressed. Thereby, even if the input direction of the force from a road surface changes because the road surface which the tire 1 contacts changes, the rigidity change of each block 23-25 which is a land part can be suppressed. From the above, the ice and snow performance can be improved by forming the plurality of sipes 3 in the respective blocks 23 to 25. Moreover, when the force A in the tire circumferential direction or the force B in the tire width direction is applied to each of the blocks 23 to 25, a change in rigidity of each of the blocks 23 to 25 can be suppressed, and the force is input to each of the blocks 23 to 25 from the road surface. Even if the direction changes, the rigidity change of each of the blocks 23 to 25 can be suppressed, so that the steering stability can be improved.

  In the above embodiment, the edge 31c is an arc, but the present invention is not limited to this. FIG. 6 is a view showing another configuration example of each sipe of the tire according to the present invention. For example, as shown in the figure, the edges 33c of the protrusions 33 formed in the blocks 23 to 25 may be elliptical arcs. In this case, the edge 33c of each protrusion 33 has a larger radius of curvature in the vicinity of the tire width direction, which is the orthogonal direction, than in the vicinity of the sipe depth direction, which is one direction.

  Moreover, in the said Example, although each sipe 3 formed in each block 23-25 is arrange | positioned so that the direction which each protrusion part 31 in each sipe 3 protrudes may become the same direction, this invention is It is not limited to this. FIG. 7 is a diagram showing another configuration example of the sipe according to the present invention. The direction of the force applied to each of the blocks 23 to 25 in the tire circumferential direction differs between when the vehicle equipped with the tire 1 assembled with the rim is driven and when the vehicle is braked. Since each of the blocks 23 to 25 falls down in the direction of the force applied to each of the blocks 23 to 25, the direction in which each of the blocks 23 to 25 falls depends on whether the vehicle is driven or braked.

  Therefore, for example, as shown in the figure, among the sipe 3 formed for each of the blocks 23 to 25, one of the sipe 3 located in one of the tire circumferential directions with the block center H of each of the blocks 23 to 25 as a boundary. Each sipe 3 (one or more sipes) and the other sipe 3 ′ (one or more other sipe) located on the other side may be formed to face each other. In other words, in each of the blocks 23 to 25, the direction in which each protruding portion 31 in one sipe 3 protrudes may be opposed to the direction in which each protruding portion 31 ′ in each other sipe 3 ′ protrudes. Thereby, the sipe 3, 3 'formed in each block 23-25 can suppress the fall of each block 23-25 regardless of the time of driving and braking of the vehicle. Stiffness change can be suppressed.

  Moreover, in the said Example, each protrusion 31 in each sipe 3 formed in the center block 23 and each of the left and right shoulder blocks 24, 25 is a sipe whose protrusion amount with respect to one wall surface 3a is one direction. The edge 31c formed between the inclined surface 31a and the outer peripheral surface 31b is protruded in the sipe depth direction while increasing in the depth direction, but the present invention is not limited to this. FIG. 8 is a diagram showing a configuration example of a sipe of a block located in the right tire shoulder portion according to the present invention. FIG. 9 is a diagram showing a configuration example of a sipe of a block located in the left tire shoulder portion according to the present invention. The input direction of the force from the road surface to the left and right shoulder blocks 24, 25 is the same direction as the sipe depth direction when the vehicle equipped with the rim-assembled tire 1 is traveling straight, but is different from the sipe depth direction when cornering. It greatly changes in the direction (direction from the tire shoulder to the tire center).

  Therefore, for example, the protruding portion 31 in the sipe 3 formed in the center block 23 that is a land portion arranged in the tire center portion, that is, the protruding portion 31 on the center side is sipe deep in one direction on the center side. The direction. Further, as shown in FIG. 8, the protruding portion 34 in the sipe 3 formed on the shoulder block 24 that is a land portion disposed on the right tire shoulder portion, that is, the protruding portion 34 on the shoulder side is the shoulder side that is in one direction. One direction may be different from the sipe depth direction. Moreover, as shown in FIG. 9, the protrusion 35 in the sipe 3 formed on the shoulder block 25 which is the land portion disposed on the left tire shoulder, that is, the protrusion 35 on the shoulder side is the shoulder side in one direction. One direction may be different from the sipe depth direction. Here, one direction on the shoulder side of the projecting portions 34 and 35 is a direction from the tire shoulder portion toward the tire center portion, and an angle θ formed with the sipe depth direction that is one direction on the center side is 45 degrees or less. It is preferable. Further, θ is preferably less than 30 degrees. The reason why the angle formed is 45 degrees is that if the angle exceeds 45 degrees, the change in block rigidity during cornering can be suppressed, but the change in block rigidity during straight running is reduced. As a result, the center side protrusion 31 formed in the center block 23 positively suppresses a change in rigidity when the vehicle goes straight, and the shoulder side protrusions 34 and 35 formed in the left and right shoulder blocks 24 and 25. As a result, it is possible to positively suppress a change in rigidity during cornering of the vehicle.

  Further, at least one of the maximum protrusion amount H, the maximum length W, and the shapes of the edges 31c, 33c to 35c (arc or elliptic arc) may be varied for each sipe 3 or each of the blocks 23 to 25. For example, each sipe 3 takes into account the wear of each block 23-25, and the edge 31c of each protrusion 31, 33-35 on each block surface 23a-25a side and the opposite side in the sipe depth direction. The shapes of 33c to 35c may be different.

  Further, for example, the protrusions 31 and 33 to 35 in each sipe 3 may be formed such that the maximum protrusion amount H decreases as it goes in the sipe depth direction. Thereby, when the sipe mold is pulled out from each sipe 3 at the time of manufacturing the tire 1, damage to the tire 1 due to the sipe mold can be further suppressed.

  Moreover, in the said Example, although each sipe 3 is extended and formed in the tire width direction, it opens to both the block wall surfaces in the tire width direction of each block 23-25, but this invention is limited to this. Is not to be done. For example, each sipe 3 may be formed to extend in an inclined direction having an angle with respect to the tire width direction. Moreover, each sipe 3 does not need to open to either of the block wall surfaces in the tire width direction of each block 23-25. Moreover, each sipe 3 may be opened only to one wall surface among these block wall surfaces.

  Moreover, in the said Example, although the some protrusion part 31,33-35 was formed in the one wall surface 3a which comprises each sipe 3, this invention is not limited to this. Since the protrusions 31 and 33 to 35 have a plurality of normal directions, one protrusion 31 and 33 to 35 may be formed for each sipe 3.

  Below, the implementation result of the running test with the conventional example and the tire 1 concerning this invention is demonstrated. Here, each tire used for this running test has a common tire size of 195 / 65R15. In addition, each tire of the above size was assembled on an appropriate rim (15 × 6 1/2 JJ) prescribed by JATMA, the air pressure was 200 kPa, and the vehicle was mounted on a rear-wheel drive vehicle with a displacement of 2000 CC.

  Here, the sipe shape in Table 1 below indicates a sipe mold for forming each sipe. The total length (mm) is the maximum length L at both ends of each protrusion in the sipe depth direction and the maximum length l at both ends in the tire width direction (in the present inventions 1 to 3, the maximum length in the sipe depth direction). The same as L). The protrusion amount (mm) is the maximum protrusion amount H in the sipe depth direction of each protrusion with respect to one wall surface (maximum protrusion amount H in the present invention) and the maximum protrusion amount h in the tire width direction (in the present inventions 1 to 3, This is the same as the maximum protrusion amount H in the sipe depth direction. The edge indicates the shape of the edge of each protrusion. The one direction indicates a direction in which the protruding amount of each protruding portion of the tire according to the present invention with respect to the tread surface increases. A sipe arrangement | positioning shows the direction of the direction sipe from which each protrusion part protrudes in each sipe formed for every block of the tire concerning this invention.

  The on-ice braking performance is one of ice and snow performance, and is an index evaluation of a braking distance from an initial speed of 40 km / h on an on-ice road surface. Steering stability is an index evaluation of the average value when running on a city snow pressure reproduction road surface by a plurality of panelists. The braking performance on ice and the handling stability are better when “Conventional Example 2” is set to 100 and the numerical value is larger.

  Here, “conventional example 1” indicates a tire having a planar shape (edge is a straight line) in which the shape of the protruding portion in the sipe extends in the tire width direction. Conventional example 2 shows a tire having a plurality of polygonal pyramid shapes (edges are straight lines) in a sipe.

  Further, "Invention 1" indicates a tire in which the size of each protrusion is the same, the edge is an arc, and one direction of all the protrusions is the sipe depth direction (see FIGS. 1 to 5). ). In the “present invention 2”, the sizes of the protrusions are all the same, the edges are arcs, one direction (one direction on the center side) of each protrusion on the center side is the sipe depth direction, The tire in which one direction (one direction on the shoulder side) in each projecting portion is inclined by 5 degrees with respect to the sipe depth direction is shown (see FIGS. 8 and 9). In “Invention 3”, the sizes of the protrusions are all the same, the edges are arcs, one direction in each protrusion on the center side (one direction on the center side) is the sipe depth direction, One direction in each protrusion (one direction on the shoulder side) is inclined 5 degrees with respect to the sipe depth direction, and the sipe arrangement is symmetric with respect to the block center of each block, that is, one of the blocks FIG. 7 shows a tire in which a direction in which each protruding portion in each sipe protrudes and a direction in which each protruding portion in each other sipe protrudes (see FIG. 7).

  As is apparent from Table 1, the tires shown in “Invention 1” to “Invention 3” have braking characteristics on the ice and steering stability compared to the tires shown in “Conventional Example 1” and “Conventional Example 2”. Improved. That is, even if the input direction of the force from the road surface changes, the rigidity change of the land portion can be suppressed.

  Further, in the present invention 2 and the present invention 3, one direction in the center side protruding portion is the sipe depth direction, and one direction in the shoulder side protruding portion is inclined by 5 degrees with respect to the sipe depth direction. In the tire shown, since it is possible to positively suppress a change in rigidity during cornering of the vehicle, steering stability can be further improved.

  Further, in the tire shown in “Invention 3” in which the sipe arrangement is symmetric with respect to the block center of each block, the collapse of each block can be suppressed regardless of whether the vehicle is driven or braked. Since the rigidity change of each block can be suppressed, the braking performance on ice and the steering stability can be further improved.

  As described above, the tire according to the present invention is useful for tires in which sipes are formed in each land portion. In particular, even if the input direction of force from the road surface changes, the change in rigidity of the land portion is suppressed. Suitable for

It is a figure which shows the structural example of the tire concerning this invention. It is a principal part enlarged view of each block. It is a figure which shows one wall surface which comprises a sipe. It is CC sectional drawing of FIG. FIG. 4 is an enlarged view of part D of FIG. 3. It is a figure which shows the other structural example of each sipe of the tire concerning this invention. It is a figure which shows the other structural example of each sipe of the tire concerning this invention. It is a figure which shows the structural example of the sipe of the block located in the right tire shoulder part concerning this invention. It is a figure which shows the structural example of the sipe of the block located in the left tire shoulder part concerning this invention.

Explanation of symbols

1 tire 2 tread portion 21 circumferential groove (groove portion)
22 Lug groove (groove)
23 center block 24 right shoulder block 25 left shoulder block 3 sipe 3a one wall surface 3b other wall surface 31, 31 ', 33 to 35 projecting portion 31a, 33a to 35a inclined surface 31b, 33b to 35b outer peripheral surface 31c, 33c to 35c Edge 32 Recessed portion 32a Inclined surface 32b Outer peripheral surface 32c Edge

Claims (11)

In the tire in which at least one or more sipes are formed in the land portion of the tread portion composed of a plurality of groove portions and a plurality of land portions,
Among the opposing wall surfaces constituting the sipe, one wall surface is formed with one or more protrusions in which the protrusion amount with respect to the one wall surface increases in one direction,
An edge is formed between the inclined surface and the outer peripheral surface constituting the protruding portion,
The tire is characterized in that the edge is at least one of an arc or an elliptical arc protruding in the one direction.   2. The tire according to claim 1, wherein the protruding portion is formed continuously in at least one of the one direction or an orthogonal direction orthogonal to the one direction.   The tire according to claim 2, wherein at least one of the ends of the edges of the protrusions adjacent in the orthogonal direction is connected to each other.   The tire according to any one of claims 1 to 3, wherein at least one of the two ends of the edge is connected to the outer peripheral surface of the protruding portion adjacent in the one direction. .   The tire according to any one of claims 1 to 4, wherein the one direction is a sipe depth direction. The one direction in the center-side protruding portion located in the tire center region of the tread portion is a sipe depth direction,
The said one direction in the protrusion part by the side of a shoulder located in the tire shoulder area | region of the said tread part differs from the said one direction in the protrusion part by the side of the center, The Claim 1 characterized by the above-mentioned. Tires. The one direction in the shoulder-side protrusion is a direction from the tire shoulder region toward the tire center region,
The tire according to claim 6, wherein an angle formed by the one direction in the shoulder-side protrusion and the one direction in the center-side protrusion is 45 degrees or less.   Among the sipe formed for each land portion, one or more sipes with respect to one or more other sipes, the projecting direction of the projecting portions in the one sipe, and the other sipe The tire according to any one of claims 1 to 7, wherein the tire is formed so as to face a protruding direction of each protruding portion in each sipe.   Each said protrusion part differs in at least any one of the maximum protrusion amount of each said protrusion part, or the maximum length of the both ends in the said one direction of the said inclined surface of the said each protrusion part, The 1st-8th characterized by the above-mentioned. The tire as described in any one of these.   10. The tire according to claim 1, wherein the maximum protrusion amount of each protrusion is 0.1 mm or more and 5.0 mm or less.   The tire according to any one of claims 1 to 10, wherein a maximum length of both ends in the one direction of the inclined surface of each protrusion is set to be 0.3 mm or more and 10 mm or less.

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