JP7417075B2 - tire - Google Patents

Description

The present invention relates to tires.

Tires installed on vehicles have multiple grooves formed on the surface of the tread for the purpose of draining water between the tread surface and the road surface when driving on wet roads. Some grooves have functions other than drainage. For example, the pneumatic tire described in Patent Document 1 extends from the opening end of the lateral groove to the shoulder main groove to a predetermined range in the extending direction of the lateral groove and a predetermined range in the extending direction of the shoulder main groove. By forming protrusions across the entire width of each groove, deterioration of braking performance and generation of noise are suppressed. Further, the pneumatic tire described in Patent Document 2 maintains snow traction performance by forming raised bottom portions in the shoulder circumferential main groove and the shoulder lug groove, excluding at least the intersection of both grooves. At the same time, it aims to reduce rolling resistance and noise. Further, the pneumatic tire described in Patent Document 3 is provided across a first groove extending in the tire circumferential direction and a second groove communicating with the first groove, and has a raised groove bottom. By forming a raised bottom part of the center land area, it improves steering stability while suppressing the deterioration of water drainage in the tread area.

Patent No. 6514063 Patent No. 6319385 Japanese Patent Application Publication No. 2018-001930

Here, some conventional tires are retreaded after a primary life cycle due to wear of the tread portion, and the tread portion is regenerated for use. In such a tire that undergoes retreading, countermeasures against stone encrustation are essential in order to enable appropriate reuse as a tire by regenerating the tread portion. In other words, when a stone enters the groove of the tread while the vehicle is running, the groove bites the stone, causing the stone to reach the groove bottom and damage the groove bottom. It has become essential to prevent stone-grabbing from occurring in the grooves. As a countermeasure against stones, for example, by providing protrusions such as those described in Patent Documents 1 to 3 in the groove, it is possible to prevent stones from entering the groove. However, in a tire with a small tire size, since the groove width becomes narrow, it becomes difficult to provide a protrusion in the groove, and there is a possibility that it becomes difficult to take measures against stone encroachment.

In addition, when driving on a wet road surface, the grooves allow water on the road surface to flow into the grooves, thereby discharging water between the tread surface and the road surface, and improving wet performance, which is the driving performance when driving on a wet road surface. However, if a protrusion is provided within the groove, there is a risk that the flow of water within the groove may be easily obstructed. In this case, it becomes difficult for the grooves to drain water between the tread surface and the road surface, so there is a possibility that the wet performance is likely to deteriorate. For this reason, it has been extremely difficult to improve the stone-grabbing performance of the groove while maintaining the wet performance.

The present invention has been made in view of the above, and an object of the present invention is to provide a tire that can improve stone-biting performance while maintaining wet performance.

In order to solve the above problems and achieve the objects, a tire according to the present invention includes a main groove extending in the tire circumferential direction, a groove depth shallower than the groove depth of the main groove, and a main groove extending in the tire width direction. A lateral groove that opens into the main groove, and a raised bottom part that is formed at a position in the main groove where the lateral groove opens, and the raised bottom part is formed continuously from the bottom of the lateral groove and is connected to the raised bottom part. is characterized in that a protrusion protruding toward the tread surface side is disposed.

Further, in the above tire, it is preferable that a surface of the raised bottom portion on the tread surface side is formed continuously from the groove bottom of the lateral groove.

Further, in the above tire, it is preferable that the protrusion is formed to protrude toward the tread surface side from a maximum depth position from the tread surface at the position of the opening of the lateral groove to the main groove. .

Further, in the above tire, it is preferable that the protrusion is connected to a groove wall of the main groove in which the lateral groove opens.

Further, in the above tire, the protrusion has a height Hp1 of the protrusion from the raised bottom part, a height Hp2 of the raised part from the bottom of the main groove, and a groove depth Hg of the main groove. preferably satisfies the relationship Hg−Hp2>Hp1.

Further, in the above tire, it is preferable that a width Wp1 of the protrusion in the groove width direction of the main groove and a groove width Wg of the main groove satisfy a relationship of Wg>Wp1.

Moreover, in the above tire, it is preferable that the width Lp1 of the protrusion in the extending direction of the main groove and the groove width Ws of the lateral groove satisfy a relationship of Ws≧Lp1.

Moreover, in the above tire, it is preferable that a plurality of the protrusions are arranged in one raised bottom part.

Further, in the above tire, it is preferable that a pair of the protrusions are arranged on both sides of an opening of the lateral groove relative to the main groove in the groove width direction of the lateral groove.

The tire according to the present invention has the effect of improving stone-biting performance while maintaining wet performance.

FIG. 1 is a meridional cross-sectional view showing essential parts of a pneumatic tire according to a first embodiment. FIG. 2 is a view taken along the line AA in FIG. FIG. 3 is a detailed schematic diagram of section B in FIG. 2. FIG. 4 is a view taken along the line CC in FIG. FIG. 5 is a perspective view of a portion where the main groove and the lateral groove shown in FIG. 3 intersect. FIG. 6 is a schematic diagram showing a state in which stones have entered the main groove. FIG. 7 is a schematic plan view of a portion where a main groove and a lateral groove intersect in a pneumatic tire according to a second embodiment. FIG. 8 is a perspective view of a portion where the main groove and the lateral groove shown in FIG. 7 intersect. FIG. 9 is a modification of the pneumatic tire according to the first embodiment, and is an explanatory diagram in which the protrusion is formed in a cylindrical shape. FIG. 10 is a modification of the pneumatic tire according to the second embodiment, and is an explanatory diagram in which the protrusions are formed with varying thicknesses. FIG. 11 is a modification of the pneumatic tire according to Embodiment 1, and is an explanatory diagram in which the protrusion is formed continuously from the raised bottom portion. FIG. 12 is a modification of the pneumatic tire according to the first embodiment, and is an explanatory diagram in which the protrusion is formed continuously from the raised bottom portion. FIG. 13 is a modification of the pneumatic tire according to Embodiment 1, and is an explanatory diagram in which the protrusion is disposed from the inside of the main groove to the inside of the lateral groove. FIG. 14 is a sectional view taken along line DD in FIG. 13. FIG. 15 is a modification of the pneumatic tire according to Embodiment 1, and is an explanatory diagram in which a lateral groove bottom raised portion is formed in the lateral groove. FIG. 16 is a chart showing the results of a tire performance evaluation test.

EMBODIMENT OF THE INVENTION Below, embodiment of the tire based on this invention is described in detail based on drawing. Note that the present invention is not limited to this embodiment. Furthermore, the components in the embodiments below include those that can be replaced and easily conceived by those skilled in the art, or those that are substantially the same.

[Embodiment 1]
In the following description, a pneumatic tire 1 will be used as an example of a tire according to the present invention. A pneumatic tire 1, which is an example of a tire, can be filled with air, an inert gas such as nitrogen, and other gases.

In addition, in the following explanation, the tire radial direction refers to a direction perpendicular to the tire rotation axis (not shown), which is the rotation axis of the pneumatic tire 1, and the inside of the tire radial direction refers to the direction perpendicular to the tire rotation axis (not shown), which is the rotation axis of the pneumatic tire 1. The radially outer side of the tire refers to the side that is away from the axis of rotation of the tire in the radial direction of the tire. Further, the tire circumferential direction refers to a direction around the tire rotation axis as the central axis. In addition, the tire width direction refers to a direction parallel to the rotational axis of the tire, the inner side in the tire width direction is the side facing the tire equatorial plane (tire equator line) CL in the tire width direction, and the outer side in the tire width direction refers to the side in the tire width direction. refers to the side away from the tire equatorial plane CL. The tire equatorial plane CL is a plane that is perpendicular to the tire rotation axis and passes through the center of the tire width of the pneumatic tire 1, and the tire equatorial plane CL is the center position of the pneumatic tire 1 in the tire width direction. The width direction center line and the position in the tire width direction coincide. The tire width is the width in the tire width direction between the outermost parts in the tire width direction, that is, the distance between the parts furthest from the tire equatorial plane CL in the tire width direction. The tire equator line refers to a line located on the tire equatorial plane CL and along the tire circumferential direction of the pneumatic tire 1.

FIG. 1 is a meridional cross-sectional view showing essential parts of a pneumatic tire 1 according to a first embodiment. The pneumatic tire 1 according to the first embodiment is, for example, a so-called radial tire for light trucks, which is used by being mounted on a small truck. The pneumatic tire 1 according to the first embodiment has a tread portion 2 disposed at the outermost portion in the tire radial direction when viewed in a meridional section, and the tread portion 2 is made of a rubber composition. It has a tread rubber layer 4. Further, the surface of the tread portion 2, that is, the portion that comes into contact with the road surface when the vehicle (not shown) on which the pneumatic tire 1 is mounted is running, is formed as a tread surface 3; It forms part of the outline. A plurality of main grooves 30 extending in the tire circumferential direction are formed in the tread surface 3 of the tread portion 2, and a plurality of land portions 20 are defined on the surface of the tread portion 2 by the plurality of main grooves 30. There is. In the first embodiment, four main grooves 30 are formed in line in the tire width direction, and two of the four main grooves 30 are arranged on each side of the tire equatorial plane CL in the tire width direction. ing.

Shoulder portions 5 are located at both outer ends of the tread portion 2 in the tire width direction, and sidewall portions 8 are disposed inside the shoulder portions 5 in the tire radial direction. That is, the sidewall portions 8 are disposed on both sides of the tread portion 2 in the tire width direction. In other words, the sidewall portions 8 are disposed at two locations on both sides of the pneumatic tire 1 in the tire width direction, and form the outermost exposed portion of the pneumatic tire 1 in the tire width direction.

Bead portions 10 are arranged on the inner side in the tire radial direction of each sidewall portion 8 located on both sides in the tire width direction. Like the sidewall portion 8, the bead portions 10 are arranged at two locations on both sides of the tire equatorial plane CL, that is, a pair of bead portions 10 are arranged on both sides of the tire equatorial plane CL in the tire width direction. There is. Each bead portion 10 is provided with a bead core 11, and a bead filler 12 is provided on the outside of the bead core 11 in the tire radial direction. The bead core 11 is an annular member formed by bundling bead wires, which are steel wires, and the bead filler 12 is a rubber member disposed outside the bead core 11 in the tire radial direction.

Further, a belt layer 14 is provided on the tread portion 2. The belt layer 14 has a multilayer structure in which a plurality of belt plies 141 to 143 are laminated, and in the first embodiment, two layers of belts 141 and 142 and one belt cover layer 143 are laminated. ing.

The belts 141 and 142 constituting the belt layer 14 are constructed by rolling a plurality of belt cords made of steel or an organic fiber material such as polyester, rayon, or nylon, and coated with rubber. The belt angle defined as the inclination angle is within a predetermined range (for example, 15° or more and 55° or less). Furthermore, the two-layer belts 141 and 142 have different belt angles. Therefore, the belt layer 14 has a so-called cross-ply structure in which two layers of belts 141 and 142 are laminated with the oblique directions of the belt cords crossing each other. That is, the two-layer belts 141 and 142 are provided as so-called crossed belts in which the belt cords of the respective belts 141 and 142 are arranged in a direction that intersects with each other.

The belt cover layer 143 is disposed outside the two-layer belts 141, 142 in the tire radial direction, and is provided as a reinforcing layer that covers the two-layer belts 141, 142 in the tire circumferential direction and reinforces the belts 141, 142. ing. The belt cover layer 143 is formed by covering a plurality of cords (not shown), which are substantially parallel to the tire circumferential direction and arranged in parallel in the tire width direction, with a coated rubber. The cords included in the belt cover layer 143 are made of, for example, steel or organic fibers such as polyester, rayon, and nylon, and the angle of the cords is within a range of ±5° with respect to the tire circumferential direction. The belt cover layer 143 is constructed by spirally wrapping a strip material in which a plurality of substantially parallel cords are coated with coated rubber from the outside in the tire radial direction around the two-layer belts 141 and 142 in the tire circumferential direction.

In the first embodiment, the belt cover layer 143 is disposed over the entire range in the tire width direction where the belts 141 and 142 are disposed, and covers the ends of the belts 141 and 142 in the tire width direction. There is. The tread rubber layer 4 of the tread portion 2 is disposed on the outer side of the belt cover layer 143 in the tread portion 2 in the tire radial direction.

A carcass layer 13 containing a radial ply cord is continuously provided on the inner side of the belt layer 14 in the tire radial direction and on the tire equatorial plane CL side of the sidewall portion 8. Therefore, the pneumatic tire 1 according to the first embodiment is configured as a so-called radial tire. The carcass layer 13 has a single layer structure consisting of one carcass ply or a multilayer structure consisting of a plurality of carcass plies laminated, and has a toroidal structure between a pair of bead portions 10 disposed on both sides in the tire width direction. It is strung together in a shape that forms the frame of the tire.

Specifically, the carcass layer 13 is arranged from one bead part 10 to the other bead part 10 of a pair of bead parts 10 located on both sides in the tire width direction, and wraps around the bead core 11 and the bead filler 12. The tire is wound back outward in the tire width direction at the bead portion 10 along the bead core 11. The bead filler 12 is a rubber material disposed in a space formed outside the bead core 11 in the tire radial direction by folding the carcass layer 13 back at the bead portion 10 in this manner. Further, the belt layer 14 is disposed on the outer side in the tire radial direction of the portion of the carcass layer 13 that spans between the pair of bead portions 10, which is located in the tread portion 2. Further, the carcass ply of the carcass layer 13 is constructed by covering a plurality of carcass cords made of steel or an organic fiber material such as aramid, nylon, polyester, or rayon with a coated rubber and rolling the cords. A plurality of carcass cords constituting the carcass ply are arranged in parallel at a certain angle to the tire circumferential direction, with the angle to the tire circumferential direction being along the tire meridian direction.

In the bead portion 10, a rim cushion rubber 17 that constitutes a contact surface of the bead portion 10 with the rim flange is disposed on the inner side in the tire radial direction and the outer side in the tire width direction of the rolled-up portion of the bead core 11 and the carcass layer 13. Further, an inner liner 16 is formed along the carcass layer 13 on the inside of the carcass layer 13 or on the inside of the carcass layer 13 in the pneumatic tire 1 . The inner liner 16 forms a tire inner surface 18 that is the inner surface of the pneumatic tire 1.

FIG. 2 is a view taken along the line AA in FIG. The four main grooves 30 formed on the tread surface 3 are arranged two on each side of the tire equatorial plane CL. The four main grooves 30 all extend in the tire circumferential direction and are repeatedly bent in the tire width direction. That is, the four main grooves 30 are formed in a zigzag shape by extending in the tire circumferential direction and vibrating in the tire width direction.

Further, in addition to the main groove 30, a plurality of lateral grooves 40 extending in the tire width direction are formed in the tread surface 3, and at least one end of the lateral groove 40 opens into the main groove 30. Each lateral groove 40 is inclined in the tire circumferential direction while extending in the tire width direction, and some of the lateral grooves 40 are bent in the tire circumferential direction while extending in the tire width direction. A plurality of land portions 20 are defined in the tread surface 3 by these plurality of main grooves 30 and lateral grooves 40 . Each land portion 20 is formed as a block-shaped land portion 20 that is partitioned in the tire width direction by the main groove 30 and partitioned in the tire circumferential direction by the lateral groove 40 .

As shown above, among the main groove 30 and the lateral groove 40 that partition the land portion 20, the main groove 30 has a groove width of 1.5 mm or more, and a groove depth of 2 mm or more and 20 mm or less. It has become. Note that the width of the main groove 30 is preferably 15 mm or less, and more preferably, the main groove 30 is a groove that has a wear indicator (slip sign) inside that indicates the end of wear. Further, the lateral groove 40 has a groove width within a range of 2 mm or more and 10 mm or less, and a groove depth within a range of 2 mm or more and 20 mm or less.

FIG. 3 is a detailed schematic diagram of section B in FIG. 2. FIG. 4 is a view taken along the line CC in FIG. FIG. 5 is a perspective view of a portion where the main groove 30 and the lateral groove 40 shown in FIG. 3 intersect. Note that since FIGS. 3 to 5 are explanatory diagrams of the raised bottom portion 60 and the protrusion 70, the main groove 30 and the lateral groove 40 are simplified, and the main groove 30 extends in the tire circumferential direction, The lateral grooves 40 are illustrated as extending in the width direction of the tire. In the main groove 30, a groove wall 35 and a groove bottom 37 are connected by a curved portion 38 in a cross-sectional view of the main groove 30 in the extending direction. The curved portion 38 connects the groove wall 35 and the groove bottom 37 in an arcuate shape with a radius of curvature within a range of, for example, 0.5 mm or more and 5 mm or less in a cross-sectional view of the main groove 30. Therefore, the groove bottom 37 of the main groove 30 is formed so that the width of the main groove 30 in the groove width direction is smaller than that in the case where the main groove 30 does not have the curved part 38.

The lateral groove 40 extending in the tire width direction and opening into the main groove 30 has a groove depth Hs shallower than a groove depth Hg of the main groove 30. The groove depth Hs of the lateral groove 40 preferably satisfies the relationship Hs≦Hg*0.5 with respect to the groove depth Hg of the main groove 30.

A raised bottom portion 60 is formed in the main groove 30 at a position where the lateral groove 40 opens. The raised bottom portion 60 is formed by protruding from the groove bottom 37 of the main groove 30 toward the tread surface 3 side, and the raised bottom portion upper surface 61 , which is the surface of the raised bottom portion 60 on the tread surface 3 side, is connected to the groove of the main groove 30 . It is located between the groove bottom 37 of the main groove 30 and the tread surface 3 in the depth direction.

Further, the raised bottom portion 60 is connected to only one of the groove walls 35 on both sides of the main groove 30 in the groove width direction. For example, as shown in FIG. 3, the lateral groove 40 opens from one side of the main groove 30 in the groove width direction, so that at the intersection where the main groove 30 and the lateral groove 40 intersect in a T-shape, , the raised bottom portion 60 is connected to the groove wall 35 in the main groove 30 on the side where the opening 41 of the lateral groove 40 relative to the main groove 30 is located. On the other hand, the raised bottom portion 60 is spaced apart from the groove wall 35 on the opposite side to the side where the opening 41 of the lateral groove 40 is located, of the groove walls 35 on both sides of the main groove 30 in the groove width direction. The raised bottom portion 60 formed in this way has a width Wp2 of the main groove 30 in the groove width direction within a range of 0.5≦(Wp2/Wg)≦0.9 with respect to the groove width Wg of the main groove 30. It is preferable to have one.

Further, the raised bottom portion 60 is formed continuously from the groove bottom 47 of the lateral groove 40 , and specifically, the raised bottom portion upper surface 61 is formed continuously from the groove bottom 47 of the lateral groove 40 . That is, in the raised bottom portion 60, the height Hp2 of the main groove 30 from the groove bottom 37 is approximately the same as the height of the groove bottom 47 of the lateral groove 40 from the groove bottom 37 of the main groove 30. More specifically, the height Hp2 of the raised bottom portion 60 from the groove bottom 37 of the main groove 30 is the height Hp2 of the lateral groove 40 from the groove bottom 37 of the main groove 30 at the position of the opening 41 of the lateral groove 40 relative to the main groove 30. The height is almost the same as the height of the bottom 47. As a result, the raised bottom portion upper surface 61 of the raised bottom portion 60 is formed as a continuous surface from the groove bottom 47 of the lateral groove 40 .

Furthermore, the width Lp2 of the raised bottom portion 60 in the extending direction of the main groove 30 is approximately the same as the groove width Ws of the lateral groove 40. Further, the position of the raised bottom portion 60 in the extending direction of the main groove 30 is approximately the same as the position of the opening 41 of the lateral groove 40 with respect to the main groove 30 in the extending direction of the main groove 30. Therefore, the raised bottom portion 60 that is formed to protrude outward in the tire radial direction from the groove bottom 37 of the main groove 30 has a width Lp2 that is the same as the groove width Ws of the lateral groove 40 and continues from the groove bottom 47 of the lateral groove 40. It is formed in the groove 30.

A protrusion 70 that protrudes toward the tread surface 3 is arranged in the raised bottom portion 60 formed in this way. The protrusion 70 is disposed on the raised bottom part upper surface 61, which is the outer surface in the tire radial direction of the raised bottom part 60, and protrudes outward from the raised bottom part upper surface 61 in the tire radial direction. In the first embodiment, the protrusion 70 is formed in a substantially prismatic shape, and the position of the outer end in the tire radial direction is inward in the tire radial direction than the opening position of the main groove 30 into the tread surface 3. It is located in Therefore, the protrusion 70 has a height Hp1 of the protrusion 70 from the bottom raised part 60, a height Hp2 of the bottom raised part 60 from the groove bottom 37 of the main groove 30, and a groove depth Hg of the main groove 30. , Hg-Hp2>Hp1. In other words, the height Hp1 of the protrusion 70 from the bottom raised part 60 is the size obtained by subtracting the height Hp2 of the bottom raised part 60 from the groove depth Hg of the main groove 30, that is, within the main groove 30. It is smaller than the size in the tire radial direction of a portion of the raised bottom portion 60 that is radially outward of the tire than the raised bottom portion upper surface 61 .

Further, the protrusion 70 has a width Wp1 of the protrusion 70 in the groove width direction of the main groove 30 and a groove width Wg of the main groove 30 satisfying the relationship Wg>Wp1, and The width Lp1 of the protrusion 70 and the groove width Ws of the lateral groove 40 satisfy the relationship Ws≧Lp1. Moreover, the width Wp1 of the protrusion 70 in the groove width direction of the main groove 30 is 0.3≦(Wp1/Wp2)≦1.0 with respect to the width Wp2 of the raised bottom portion 60 in the groove width direction of the main groove 30. Preferably, it is within this range. Moreover, the width Lp1 of the protrusion 70 in the extending direction of the main groove 30 is 0.3≦(Lp1/Lp2)≦1.0 with respect to the width Lp2 of the raised bottom portion 60 in the extending direction of the main groove 30. Preferably, it is within this range. In this case, the width Wp1 of the protrusion 70 in the groove width direction of the main groove 30 and the width Lp1 of the protrusion 70 in the extending direction of the main groove 30 are the widths of the connecting surfaces of the protrusion 70 to the bottom raised part upper surface 61, respectively. It has become.

In the first embodiment, the width Wp1 of the protrusion 70 in the groove width direction of the main groove 30 is smaller than the width Wp2 of the raised bottom part 60 in the groove width direction of the main groove 30. The width Lp1 of the protrusion 70 in the direction in which the main groove 30 extends is smaller than the width Lp2 of the raised bottom portion 60 in the direction in which the main groove 30 extends. Further, the protrusion 70 has a corner R formed near the portion connected to the raised bottom portion upper surface 61, and the portion of the protrusion 70 connected to the raised bottom portion 60 is reinforced.

Since the pneumatic tire 1 according to the first embodiment is a radial tire for light trucks, it is mainly used by being attached to light trucks. When the pneumatic tire 1 is mounted on a vehicle, the pneumatic tire 1 is mounted on a rim wheel in an inflated state.

When a vehicle equipped with the pneumatic tire 1 runs, the pneumatic tire 1 rotates while the lower tread surface 3 of the tread surface 3 contacts the road surface. When a vehicle equipped with pneumatic tires 1 runs on a dry road surface, the frictional force between the tread surface 3 and the road surface is used to transmit driving force and braking force to the road surface, and to generate turning force. It runs by letting it run. Furthermore, when driving on a wet road surface, water between the tread surface 3 and the road surface enters the main groove 30, lateral grooves 40, etc., and these grooves drain water between the tread surface 3 and the road surface. while driving. This makes it easier for the tread surface 3 to come into contact with the road surface, and the frictional force between the tread surface 3 and the road surface allows the vehicle to run.

Here, stones 100 (see FIG. 6) may fall on the road surface on which the vehicle is running, and when the vehicle is running, such stones 100 on the road surface may fall into the main grooves 30 or lateral grooves of the tread surface 3. It can reach 40. For example, when a vehicle travels on a road surface where many stones 100 are scattered, the stones 100 on the road surface tend to get into the main grooves 30 and the lateral grooves 40. In particular, since the main groove 30 continues to open to the road surface when the pneumatic tire 1 rotates, stones 100 located at the same position in the tire width direction as the main groove 30 on the road surface are It's easier to get into. At this time, if the size of the stone 100 is smaller than the groove width of the main groove 30, even if the stone 100 enters the main groove 30, the stone 100 is immediately discharged from the main groove 30. Further, if the size of the stone 100 is significantly larger than the groove width of the main groove 30, the stone 100 is difficult to enter into the main groove 30.

On the other hand, if the size of the stone 100 is slightly larger than the groove width of the main groove 30, when the main groove 30 of the rotating pneumatic tire 1 is located on the stone 100, the width of the main groove 30 is As the land portions 20 on both sides undergo elastic deformation due to the ground load, the stone 100 easily enters the main groove 30. In particular, the area where the main groove 30 and the lateral groove 40 intersect has a larger opening area than the area where only the main groove 30 and the lateral groove 40 intersect. It's easier to get into the parts that you do.

In this way, when a stone 100 that is slightly larger than the groove width of the main groove 30 enters the area where the main groove 30 and the horizontal groove 40 intersect due to the elastic deformation of the land portion 20, the stone 100 has a land portion due to its elasticity. The state held in the main groove 30 is maintained by the pressure applied from the main groove 20 or the main groove 30. That is, the stone 100 is bitten into the main groove 30, and stone biting occurs in the main groove 30.

When stones in the main groove 30 occur, when the pneumatic tire 1 rotates and comes into contact with the road surface, the force in the direction of the groove bottom 37 of the main groove 30 is applied to the stone from the road surface. This force causes the stone 100 to move in the direction of the groove bottom 37 of the main groove 30 and come into contact with the groove bottom 37 more easily. If the stone 100 stuck in the main groove 30 comes into contact with the groove bottom 37 of the main groove 30 with a large force due to the force acting from the road surface, the groove bottom 37 may be damaged.

On the other hand, in the pneumatic tire 1 according to the first embodiment, the raised bottom portion 60 and the protrusion 70 are arranged at the intersection of the main groove 30 and the lateral groove 40, so that stone entrainment is less likely to occur. ing. FIG. 6 is a schematic diagram showing a state in which the stone 100 has entered the main groove 30. In other words, the stones 100 on the road surface easily enter the portion where the main groove 30 and the lateral groove 40 intersect, but in the first embodiment, the portion where the main groove 30 and the lateral groove 40 intersect has a raised bottom portion. 60 and the protrusion 70 are arranged, the stone 100 that attempts to enter the intersection of the main groove 30 and the lateral groove 40 comes into contact with the protrusion 70 on the raised bottom part 60. Therefore, even if a stone 100 on the road surface tries to enter the intersection of the main groove 30 and the lateral groove 40, the stone 100 will not enter the main groove 30 by contacting the protrusion 70 and will not enter the main groove 30. It is discharged from the groove 30. As a result, stone entrainment in the main groove 30 is suppressed, and damage to the groove bottom 37 of the main groove 30 when stone entrainment occurs in the main groove 30 is suppressed, so stone entrainment performance, which is performance against stone entrainment, is suppressed. will improve.

Here, the main grooves 30 play the role of draining water between the tread surface 3 and the road surface by causing water on the road surface to flow into the main grooves 30 when driving on a wet road surface, but they also play a role of draining water between the tread surface 3 and the road surface. If the raised bottom portion 60 is disposed within the main groove 30 for the purpose, there is a possibility that the raised bottom portion 60 may block the flow of water flowing through the main groove 30 . In this case, since drainage performance in the main groove 30 is reduced, there is a possibility that wet performance, which is driving performance when driving on a wet road surface, is likely to be reduced. In order to ensure wet performance, if the height of the bottom raised part 60 from the groove bottom 37 of the main groove 30 is lowered, when the stone 100 enters near the part of the main groove 30 where the horizontal groove 40 opens, the stone 100 Since it becomes difficult to contact the raised bottom part 60, it becomes difficult to eject the stones 100 from the raised bottom part 60, and there is a possibility that it becomes difficult to suppress stone biting. On the other hand, if the height of the raised bottom part 60 from the groove bottom 37 of the main groove 30 is increased, the stones 100 trying to enter the main groove 30 will easily come into contact with the raised bottom part 60, so that the raised bottom part 60 will not hold the stone 100. Although it becomes easier to drain water, since the raised bottom portion 60 tends to block the flow of water flowing through the main groove 30, there is a possibility that the drainage performance in the main groove 30 tends to deteriorate.

On the other hand, in the pneumatic tire 1 according to the first embodiment, the raised bottom portion 60 is formed continuously from the groove bottom 47 of the lateral groove 40, so the height of the raised bottom portion 60 from the groove bottom 37 of the main groove 30 is It is possible to prevent the height Hp2 from becoming too high, and it is possible to prevent the flow of water flowing through the main groove 30 from being blocked. Further, by forming the raised bottom portion 60 continuously from the groove bottom 47 of the lateral groove 40, a flow path for water flowing between the main groove 30 and the lateral groove 40 can be secured. Thereby, drainage performance in the main groove 30 and the lateral groove 40 can be ensured.

Furthermore, since a protrusion 70 that protrudes toward the tread surface 3 is disposed on the bottom raised portion 60, the flow of water flowing within the main groove 30 or between the main groove 30 and the lateral groove 40 is prevented from being obstructed as much as possible. At the same time, the stone 100 attempting to enter the intersection of the main groove 30 and the lateral groove 40 can be brought into contact with the protrusion 70. In other words, stones 100 on the road surface easily enter the area where the main groove 30 and the lateral groove 40 intersect, but the protrusion 70 is arranged in the raised bottom part 60 that is continuously formed from the groove bottom 47 of the lateral groove 40. By doing so, the protrusions 70 can eject stones 100 that try to enter the portion where the main groove 30 and the lateral groove 40 intersect. Thereby, the stones 100 that try to enter the main groove 30 can be discharged from the main groove 30 while ensuring drainage performance in the main groove 30 and the lateral groove 40, and the occurrence of stone entrapment can be suppressed. As a result, stone-biting performance can be improved while maintaining wet performance.

In addition, since the bottom raised part upper surface 61 of the bottom raised part 60 is formed continuously from the groove bottom 47 of the lateral groove 40, it is possible to more reliably secure a flow path for water flowing between the main groove 30 and the lateral groove 40. This makes it possible to ensure drainage performance in the main grooves 30 and lateral grooves 40. As a result, the stone biting performance can be improved while maintaining the wet performance more reliably.

In addition, the protrusion 70 has a height Hp1 of the protrusion 70 from the bottom raised part 60, a height Hp2 of the bottom raised part 60 from the groove bottom 37 of the main groove 30, and a groove depth Hg of the main groove 30. Since the relationship of Hg-Hp2>Hp1 is satisfied, damage to the protrusion 70 when the vehicle is running can be suppressed. In other words, if the height Hp1 of the protrusion 70, the height Hp2 of the raised bottom part 60, and the groove depth Hg of the main groove 30 have a relationship of Hg-Hp2<Hp1, then the protrusion 70 is lower than the main groove 30. Since the protrusion 70 protrudes from the inside toward the tread surface 3, the protrusion 70 may come into contact with the road surface when the vehicle is running, and the protrusion 70 may be easily damaged. For example, if the protrusion 70 comes into contact with the road surface and breaks off, it becomes difficult for the protrusion 70 to eject the stones 100 that try to enter the main groove 30, which prevents stones from getting stuck in the main groove 30. There is a possibility that it will become difficult.

On the other hand, when the height Hp1 of the protrusion 70, the height Hp2 of the raised bottom part 60, and the groove depth Hg of the main groove 30 satisfy the relationship Hg-Hp2>Hp1, the protrusion 70 is the main groove. Since protrusion from inside the groove 30 toward the tread surface 3 can be suppressed, damage to the protrusion 70 when the vehicle is running can be suppressed. Thereby, the stones 100 that try to enter the main groove 30 can be ejected by the protrusion 70 over a long period of time. As a result, the stone biting performance can be improved more reliably.

Further, since the width Wp1 of the protrusion 70 in the groove width direction of the main groove 30 and the groove width Wg of the main groove 30 satisfy the relationship Wg>Wp1, the protrusion 70 is 30, the ease of water flow can be ensured more reliably. In other words, if the relationship between the width Wp1 of the protrusion 70 and the groove width Wg of the main groove 30 is Wg≦Wp1, the width Wp1 of the protrusion 70 in the groove width direction of the main groove 30 is too large. When water flows in the groove 30, there is a risk that the flow of water may be blocked by the protrusion 70. In this case, there is a possibility that it becomes difficult to ensure drainage performance in the main groove 30.

On the other hand, if the relationship between the width Wp1 of the protrusion 70 and the groove width Wg of the main groove 30 is Wg>Wp1, a flow path for water when flowing inside the main groove 30 can be secured. Therefore, drainage performance in the main groove 30 can be ensured more reliably. As a result, wet performance can be improved more reliably.

In addition, since the width Lp1 of the protrusion 70 in the extending direction of the main groove 30 and the groove width Ws of the lateral groove 40 satisfy the relationship Ws≧Lp1, the protrusion 70 It is possible to more reliably ensure the ease of water flowing between the grooves 40 and the lateral grooves 40. In other words, if the relationship between the width Lp1 of the protrusion 70 and the groove width Ws of the lateral groove 40 is Ws<Lp1, the width Lp1 of the protrusion 70 in the extending direction of the main groove 30 is too large. There is a possibility that the protrusion 70 may block the flow of water flowing between the groove 30 and the horizontal groove 40. In this case, there is a possibility that it will be difficult to ensure drainage performance in the main grooves 30 and the lateral grooves 40.

On the other hand, if the relationship between the width Lp1 of the protrusion 70 and the groove width Ws of the lateral groove 40 is Ws≧Lp1, the water flow path when water flows between the main groove 30 and the lateral groove 40 is can be ensured, and drainage performance in the main grooves 30 and lateral grooves 40 can be ensured more reliably. As a result, wet performance can be improved more reliably.

[Embodiment 2]
The pneumatic tire 1 according to the second embodiment has substantially the same configuration as the pneumatic tire 1 according to the first embodiment, but is characterized in that a plurality of protrusions 70 are arranged on one raised bottom part 60. Since the other configurations are the same as those of the first embodiment, their explanation will be omitted and the same reference numerals will be given.

FIG. 7 is a schematic plan view of a portion where the main groove 30 and the lateral groove 40 intersect in the pneumatic tire 1 according to the second embodiment. FIG. 8 is a perspective view of a portion where the main groove 30 and the lateral groove 40 shown in FIG. 7 intersect. Similar to the pneumatic tire 1 according to Embodiment 1, the pneumatic tire 1 according to the second embodiment has a raised bottom portion 60 formed in the main groove 30 at a position where the lateral groove 40 opens, and the raised bottom portion 60 has a tread surface. A protrusion 70 protruding to the third side is arranged. The second embodiment differs from the first embodiment in that a plurality of protrusions 70 arranged on the bottom raised part 60 are arranged on one bottom raised part 60 . Specifically, a pair of protrusions 70 are arranged in one raised bottom part 60, and the pair of protrusions 70 are arranged on both sides of the opening 41 of the lateral groove 40 relative to the main groove 30 in the groove width direction of the lateral groove 40. It is located in

That is, in the second embodiment, the width Lp2 of the raised bottom portion 60 in which the protrusion 70 is arranged in the extending direction of the main groove 30 is larger than the groove width Ws of the lateral groove 40. For this reason, the raised bottom portions 60 are arranged so as to protrude from the openings 41 of the lateral grooves 40 relative to the main grooves 30 to both sides in the extending direction of the main grooves 30 .

A pair of protrusions 70 arranged on the bottom raised part 60 are arranged in parts of the bottom raised part 60 that protrude from the openings 41 of the lateral grooves 40 on both sides in the extending direction of the main groove 30 . Therefore, in the second embodiment, the protrusions 70 do not overlap the openings 41 of the lateral grooves 40 in the extending direction of the main groove 30, and the pair of protrusions 70 do not overlap in the extending direction of the main groove 30 or in the lateral grooves. 40 are connected to the groove walls 35 of the main groove 30 on both sides of the opening 41 of the lateral groove 40 in the groove width direction. In other words, the pair of protrusions 70 have approximately the same size as the groove width Ws of the lateral groove 40 and are spaced apart from each other in the extending direction of the main groove 30, and the lateral groove The grooves 40 are connected at positions on both sides of the opening 41 of the lateral groove 40 in the groove width direction.

Therefore, in the second embodiment, the raised bottom portion 60 has a width Lp2 of the raised bottom portion 60 in the extending direction of the main groove 30, a width Lp1 of the protrusion 70 in the extended direction of the main groove 30, and an opening with respect to the main groove 30. The relationship between the groove width Ws of the lateral groove 40 at the position of the portion 41 is Lp2=Lp1+Lp1+Ws. Further, in the second embodiment, the width Wp1 of the protrusion 70 in the groove width direction of the main groove 30 is approximately the same as the width Wp2 of the raised bottom portion 60 in the groove width direction of the main groove 30. As shown, the pair of protrusions 70 are spaced apart from each other by approximately the same size as the groove width Ws of the lateral groove 40, and the width Wp1 of the protrusion 70 in the groove width direction of the main groove 30 is the same as that of the raised bottom part 60 in the same direction. The raised bottom portion 60 and the pair of protrusions 70 are formed in a groove-like shape in which the lateral groove 40 extends toward the inside of the main groove 30.

Note that the width Lp1 of the pair of protrusions 70 disposed in one raised bottom portion 60 may be the same in the direction in which the main groove 30 extends; The width Lp1 of the protrusions 70 may be different between the protrusions 70.

In the pneumatic tire 1 according to the second embodiment, since a plurality of protrusions 70 are arranged on one raised bottom part 60, the rigidity of the entire protrusion 70 arranged on one raised bottom part 60 can be increased. The stones 100 that are likely to enter the main groove 30 can be more reliably ejected by the protrusion 70. Furthermore, by ensuring the rigidity of the entire protrusion 70, damage to the protrusion 70 can be suppressed even when the stone 100 trying to enter the main groove 30 contacts the protrusion 70 with a large load. I can do it. Thereby, the stones 100 that try to enter the main groove 30 can be ejected by the protrusion 70 over a long period of time. As a result, stone-biting performance can be improved more reliably.

Furthermore, since a pair of protrusions 70 are arranged on both sides of the opening 41 of the lateral groove 40 relative to the main groove 30 in the groove width direction of the lateral groove 40, stones that try to enter the position where the lateral grooves 40 intersect in the main groove 30 are prevented. 100 can be discharged more reliably by the protrusion 70. In other words, the area where the main groove 30 and the horizontal groove 40 intersect has a large opening area, making it easy for the stone 100 to enter, but the pair of protrusions 70 are arranged on both sides of the opening 41 of the horizontal groove 40 Thereby, the pair of protrusions 70 can more reliably eject stones 100 that try to enter the intersection of the main groove 30 and the lateral groove 40. As a result, the stone biting performance can be improved more reliably.

[Modified example]
Note that in the first and second embodiments described above, the protrusion 70 is formed in a prismatic shape, but the protrusion 70 may be formed in a shape other than a prismatic shape. FIG. 9 is a modification of the pneumatic tire 1 according to the first embodiment, and is an explanatory diagram in which the protrusion 70 is formed in a cylindrical shape. FIG. 10 is a modification of the pneumatic tire 1 according to the second embodiment, and is an explanatory diagram in which the protrusion 70 is formed with varying thickness. For example, as shown in FIG. 9, the protrusion 70 may be formed in a substantially cylindrical shape. That is, the protrusion 70 may be formed in a substantially cylindrical shape and disposed on the raised bottom part upper surface 61 of the raised bottom part 60 with the axial direction being in the direction of the groove depth of the main groove 30. Further, when the pair of protrusions 70 are arranged on both sides of the opening 41 of the lateral groove 40 and connected to the groove wall 35 of the main groove 30, the protrusions 70 are arranged on the bottom raised part 60 side, as shown in FIG. The main groove 30 may be formed in such a shape that the thickness in the groove width direction becomes narrower toward the tread surface 3 side. The protrusion 70 may be formed in other shapes such as a hexagonal columnar shape or a conical shape. I don't care.

Further, in the first and second embodiments described above, the protrusion 70 is arranged on the bottom raised part upper surface 61 of the bottom raised part 60, but the bottom raised part 60 does not have the planar bottom raised part upper surface 61, and the protrusion 70 may be formed continuously from the raised bottom portion 60. 11 and 12 are modified examples of the pneumatic tire 1 according to the first embodiment, and are explanatory diagrams in a case where the protrusion 70 is formed continuously from the raised bottom part 60. The raised bottom part 60 may not have the raised bottom part upper surface 61 as shown in FIGS. 11 and 12, and the protrusion 70 may be continuously formed on the outside of the raised bottom part 60 in the tire radial direction. In this case, the protrusion 70 may have a planar outer end in the tire radial direction, as shown in FIG. 11, or a corner part, as shown in FIG. It may be formed in a shape. By forming the protrusion 70 continuously from the raised bottom part 60, the volume becomes larger and the rigidity is improved, and stress concentration is less likely to occur, so that the protrusion 70 is prevented from protruding when a large load is applied to the protrusion 70. Damage such as blistering of the portion 70 can be suppressed. Thereby, the stones 100 that try to enter the main groove 30 can be ejected by the protrusion 70 over a long period of time, and the stone biting performance can be improved more reliably.

Further, in the first and second embodiments described above, the protrusion 70 is arranged only within the main groove 30, but the protrusion 70 may be arranged outside the main groove 30. FIG. 13 is a modification of the pneumatic tire 1 according to the first embodiment, and is an explanatory diagram in a case where the protrusion 70 is arranged from the inside of the main groove 30 to the inside of the lateral groove 40. FIG. 14 is a sectional view taken along line DD in FIG. 13. For example, as shown in FIGS. 13 and 14, the protrusion 70 disposed on the bottom raised portion 60 located within the main groove 30 enters into the lateral groove 40 from the opening 41 of the lateral groove 40 relative to the main groove 30, and enters into the lateral groove 40. It may be arranged from inside 30 to inside lateral groove 40. That is, the protrusion 70 may be arranged from the raised bottom part 60 in the main groove 30 to the groove bottom 47 of the lateral groove 40.

Further, in the first and second embodiments described above, the raised bottom portion is formed only in the main groove 30, but the raised bottom portion may be formed in other than the main groove 30. FIG. 15 is a modification of the pneumatic tire 1 according to the first embodiment, and is an explanatory diagram in a case where a lateral groove bottom raised portion 48 is formed in the lateral groove 40. For example, as shown in FIG. 15, the lateral groove 40 opening into the main groove 30 may have a raised lateral groove bottom portion 48 in which the groove bottom 47 near the opening 41 is raised. In this case, it is preferable that the raised bottom part upper surface 61 of the raised bottom part 60 formed in the main groove 30 be formed continuously from the raised bottom part 48 of the lateral groove. Further, it is preferable that the groove depth Hs of the lateral groove 40 at the position of the lateral groove bottom raised portion 48 satisfies the relationship Hs≦Hg*0.5 with respect to the groove depth Hg of the main groove 30.

Regardless of the form of the protrusion 70 as illustrated in FIGS. 13 and 14 or the form of the lateral groove 40 as illustrated in FIG. 15, the position of the opening 41 in the lateral groove 40 to the main groove 30 It suffices if it is formed to protrude toward the tread surface 3 side from the maximum depth position P from the tread surface 3 at . The protrusion 70 is formed to protrude toward the tread surface 3 from the maximum depth position P from the tread surface 3 at the position of the opening 41 of the lateral groove 40, so that the main groove 30 and the lateral groove 40 intersect. The protrusion 70 can more reliably eject the stone 100 that is about to enter the area where the stone 100 is disposed. As a result, the stone biting performance can be improved more reliably.

Further, in the first and second embodiments described above, as an example of the portion where the raised bottom portion 60 and the protrusion 70 of the main groove 30 are arranged, the main groove 30 is explained, the raised bottom part 60 and the protrusion 70 of the main groove 30 are the part where the main groove 30 and the lateral groove 40 intersect in a T-shape. It may be placed elsewhere. The raised bottom portion 60 and the protrusion 70 of the main groove 30 are formed by, for example, the lateral groove 40 opening from both sides of the main groove 30 in the groove width direction, so that the main groove 30 and the lateral groove 40 form a cross shape. They may be placed at the intersection. Further, the relative angle at which the main groove 30 and the lateral groove 40 intersect may be other than 90° or an angle other than the angle illustrated in FIG. 2 . Further, in the first and second embodiments described above, four main grooves 30 are formed, and each main groove 30 has a zigzag shape, but the number and shape of the main grooves 30 may be other than this. Good too.

Further, in the first and second embodiments described above, the pneumatic tire 1 was used as an example of the tire according to the present invention, but the tire according to the present invention may be other than the pneumatic tire 1. The tire according to the present invention may be, for example, a so-called airless tire that can be used without being filled with gas.

[Example]
FIG. 16 is a chart showing the results of a tire performance evaluation test. Hereinafter, regarding the above tires, performance evaluation tests conducted on a conventional tire and a tire according to the present invention will be described. The performance evaluation tests were conducted on wet performance, which is the driving performance on a wet road surface, and stone-biting performance, which is the performance that measures the difficulty of stone-biting.

The performance evaluation test was conducted using pneumatic tires filled with air, and the tire name specified by JATMA was 195/85R16 B4N size tire was attached to a rim wheel with a rim size of 16 x 5 1/2J. The tires were assembled, the air pressure was adjusted to 600 kPa, the test tires were mounted on a 2B light truck evaluation vehicle, and the evaluation vehicle was driven.

The evaluation method for each test item was as follows: For wet performance, a braking test was conducted on a wet road in accordance with ECE R117-02 (ECE Regulation No. 117 Revision 2), and for wet grip braking performance, a conventional example described below was conducted. It was evaluated by expressing it as an index set to 100. The higher the number, the better the braking performance on wet road surfaces, indicating higher wet performance. In addition, regarding wet performance, if the index is 97 or more, it is assumed that a decrease in wet performance is suppressed compared to the conventional example.

Regarding stone-biting performance, the number of stones 100 remaining in the main groove 30 was counted when the evaluation vehicle equipped with the test tires was run off-road for 10 hours and then on-road for 2 hours. The evaluation was made by expressing the reciprocal of the number of stones 100 stuck in 30 as an index with the conventional example described below being 100. The larger the numerical value, the fewer the number of stones 100 bitten in the main groove 30, which indicates that the stone biting performance is excellent.

The performance evaluation test was conducted on seven types of tires: a conventional tire, which is an example of a conventional tire, and Examples 1 to 6, which are an example of a tire according to the present invention. Among these, in the conventional tire, the raised bottom portion 60 is formed at the position where the lateral groove 40 opens in the main groove 30, but the protrusion 70 is not arranged in the raised bottom portion 60.

In contrast, in Examples 1 to 6, which are examples of tires according to the present invention, the raised bottom portion 60 is formed at the position where the lateral groove 40 opens in the main groove 30, and the protrusion 70 is arranged in the raised bottom portion 60. has been done. Furthermore, the tires according to Examples 1 to 6 have a relationship between the height Hp1 of the protrusion 70, the height Hp2 of the raised bottom part 60 of the main groove 30, and the groove depth Hg of the main groove 30, and the groove depth Hg of the main groove 30. The relationship between the width Wp1 of the protrusion 70 in the width direction and the groove width Wg of the main groove 30, the relationship between the width Lp1 of the protrusion 70 in the extending direction of the main groove 30 and the groove width Ws of the lateral groove 40, one raised bottom part The number of protrusions 70 arranged in the main groove 60 and whether or not the protrusions 70 are connected to the groove wall 35 of the main groove 30 are different.

As a result of performing performance evaluation tests using these tires, as shown in Figure 16, the tires according to Examples 1 to 6 improved rock-biting performance while suppressing a decline in wet performance compared to the conventional example. I found out that it can be done. In other words, the tires according to Examples 1 to 6 can improve stone catching performance while maintaining wet performance.

1 Pneumatic tires (tires)
2 Tread portion 3 Tread surface 4 Tread rubber layer 8 Sidewall portion 10 Bead portion 11 Bead core 13 Carcass layer 14 Belt layer 16 Inner liner 20 Land portion 30 Main groove 35 Groove wall 37, 47 Groove bottom 40 Lateral groove 41 Opening portion 48 Lateral groove bottom raising Part 60 Raised bottom part 61 Upper surface of raised bottom part 70 Projection

Claims (9)

A main groove extending in the circumferential direction of the tire;
a lateral groove having a groove depth shallower than that of the main groove, extending in the tire width direction and opening into the main groove;
a raised bottom portion formed in the main groove at a position where the lateral groove opens;
Equipped with
The raised bottom portion is formed continuously from the bottom of the lateral groove,
A tire characterized in that a protrusion protruding toward the tread surface is disposed on the bottom raised portion. The tire according to claim 1, wherein the raised bottom portion has a surface on the tread surface side that is formed continuously from the bottom of the lateral groove. The tire according to claim 1 or 2, wherein the protrusion is formed to protrude toward the tread surface from a maximum depth position from the tread surface at the position of the opening to the main groove in the lateral groove. . The tire according to any one of claims 1 to 3, wherein the protrusion is connected to a groove wall of the main groove into which the lateral groove opens. The height Hp1 of the protrusion from the bottom raised part, the height Hp2 of the raised bottom part from the bottom of the main groove, and the groove depth Hg of the main groove are Hg-Hp2. The tire according to any one of claims 1 to 4, which satisfies the relationship: >Hp1. The protrusion according to any one of claims 1 to 5, wherein a width Wp1 of the protrusion in the groove width direction of the main groove and a groove width Wg of the main groove satisfy the relationship Wg>Wp1. tires. The protrusion according to any one of claims 1 to 6, wherein a width Lp1 of the protrusion in the extending direction of the main groove and a groove width Ws of the lateral groove satisfy the relationship Ws≧Lp1. tire. The tire according to any one of claims 1 to 7, wherein a plurality of the protrusions are arranged in one raised bottom part. The tire according to claim 8, wherein a pair of the protrusions are arranged on both sides of an opening of the lateral groove relative to the main groove in the groove width direction of the lateral groove.

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