JP2001354011A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of improving the on-show performance without sacrificing the on-ice performance. SOLUTION: A recess 20 having a bottom part 20A which is higher than a groove bottom and lower than a tread 19 of a block-like flat portion 18 is provided on an edge on a step-in side and a step-out side of the block-like flat portion 18. By providing the recess 20, the rigidity in the vicinity of the tread 19 of the block-like flat portion 18 is degraded, and the part in the vicinity of the tread 19 is appropriately inclined and deformed when the block-like flat portion 18 is brought into contact with the ground, and the block-like flat portion becomes easy to bite in the snow surface to improve the on-snow traction performance. The on-ice performance is not sacrificed because the on-snow traction performance is not improved by increasing the area of the groove.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire for use in automobiles running on snowy roads, and more particularly to a pneumatic tire with improved on-snow performance.

[0002]

2. Description of the Related Art In some cases, winter tires are used instead of summer tires in order to travel on ice and snowy roads in winter.

[0003]

Conventionally, in a pneumatic tire for winter, when running on a snowy road, if the tire rotation is accelerated at the time of starting, the tire cannot grip the snowy road and the tire may not be able to grip the snowy road. There is a disadvantage that the tire cannot grip the snowy road during braking and the braking distance is extended.

[0004] In order to improve the acceleration (hereinafter referred to as snow traction) when starting on a snowy road and the deceleration during braking (hereinafter referred to as snow braking), the area of the groove portion of the tread pattern has been increased. However, the required performance of the same winter tires, ice performance, decreases when the area of the groove is increased because the area in contact with ice is reduced.Therefore, the area of the groove is reduced from the balance between the performance on snow and the performance on ice. At present, it was not possible to improve the performance on snow by increasing it extremely.

[0005] However, even in the case of a pneumatic tire for winter, when the rotation of the tire is accelerated at the time of starting on a snowy road, if the degree of acceleration is too great, the tire cannot grip the snowy road and the tire cannot travel on the snow. There was a difficulty to slip.

Conventionally, in order to improve the acceleration (hereinafter referred to as snow traction performance) at the time of starting on a snowy road and the deceleration (hereinafter referred to as snow braking performance) at the time of braking, a groove of a tire tread pattern has been conventionally formed. Although the area has been increased, the performance on ice, which is the required performance of the same winter tires, has the drawback that if the area of the groove is increased, the area that comes into contact with ice decreases, and the performance on snow is reduced. There was a limit to the improvement of traction performance on snow and braking performance on snow due to the compatibility of the performance on ice and the performance due to the grooves.

In view of the above, an object of the present invention is to provide a pneumatic tire that can improve on-snow performance without sacrificing on-ice performance.

[0008]

The invention according to claim 1 is a pneumatic tire provided with a plurality of block-shaped land portions which are divided by a plurality of main grooves crossing each other on a tread. The land portion is characterized in that a concave portion having a bottom portion higher than the groove bottom of the main groove and lower than the land portion tread surface is provided at an edge between the land portion tread surface and the land portion side surface.

Next, the operation of the pneumatic tire according to the first aspect will be described.

In the pneumatic tire according to the first aspect, the block-shaped land portion 100 provided with the concave portion 102 at the edge as shown in FIG.
When the deformation as shown in (1) is made, the rigidity is high in the portion near the groove bottom of the main groove due to the large volume of the land, and the block-like land 1
The deformation (tilt) of 00 is small.

On the other hand, the portion close to the land tread 106 has low rigidity due to the small volume of the land portion, and the block-like land portion 100 has a low rigidity.
Is greater than the deformation (see FIG. 14B) when there is no recess 102 (see FIG. 14A).

It has been found from various experiments by the inventor that it is more effective to deform (tilt) the vicinity of the edge than in the past in order to make the edge of the block-shaped land portion 100 penetrate deeply into the snow surface.

As a method of deforming (tilting) the vicinity of the edge as compared with the conventional method, a method of reducing the size of the entire block-shaped land portion (enlarging the groove width), a method of using low-hardness rubber for the tread, and the like can be considered. .

However, when the size of the block-shaped land portion is simply reduced, there is a problem that the ground contact area is reduced and performance on ice and the like are deteriorated. In addition, when a low hardness rubber is used for the tread, there is a problem that abrasion resistance and the like are deteriorated.

On the other hand, according to the structure of the present invention, in the portion where the concave portion is provided, rigidity is secured at a portion near the groove bottom (the base of the block-shaped land portion), and deformation is somewhat increased at a portion near the land portion tread surface. Therefore, it is possible to improve the performance on snow while solving the above problem.

When the vehicle travels in fresh snow, rough snow, or medium-pressure snow, snow enters the main groove (lateral groove) and is compressed to form a snow column. In the running of fresh snow, coarse snow, and medium-pressure snow, the greater the snow column shearing force of the snow entering the main groove, the better the performance on snow. According to the configuration of the present invention, the concave portion is formed in the block-shaped land portion, and the volume of the main groove is not reduced, so that the snow column shearing force is not reduced, and fresh snow, coarse snow, medium-pressure snow There is no danger of deteriorating the on-snow performance. In addition, there is no possibility that the wet performance is reduced.

On the other hand, when the vehicle runs on high-pressure snow near an ice floe, snow rarely enters the main groove, and the edge effect of the edge of the block-shaped land portion becomes dominant.

[0018] Traction (brake) on tires on snow
In order to demonstrate the performance, the edge effect generated by the edge part penetrating the snow and scratching the snow described above, and the snow column compressed by entering the groove and rolling the tire by rolling the tire The issue is how to improve the generated snow column shearing force.

Further, in order to improve the edge effect, it is necessary to increase the deformation (inclination) of the edge portion and to penetrate the snow more than before, and to increase the snow column shear force, the groove volume must be increased. What is necessary is just to make the snow column part to take and shear large.

It is known that snow quality varies depending on the region, the climate, and the like. The properties of snow vary widely from high-pressure snow near an ice plate to relatively soft fresh snow, coarse snow, and medium-pressure snow.

Since the edge effect is generated by scratching the snow, the tire effect is generated when the tire is rolling, regardless of the snow quality. However, the snow column shearing force is generated when the snow does not enter the groove (the snow is compressed). No snow column is formed), no shearing force occurs.

Snow column shearing force acts in relatively soft snow, but in hard snow close to an ice floe, snow does not sufficiently enter the groove, and the effect of snow column shearing force is reduced.

That is, in order to improve the performance widely from high-pressure snow to fresh snow, coarse snow, and medium-pressure snow (in particular, to improve the performance with high-pressure snow), it is necessary to increase the deformation of the edge portion to improve the edge effect. Is the best.

Furthermore, in order to maintain the performance due to the snow column shearing force even in fresh snow, coarse snow, and medium-pressure snow, a larger groove volume is more advantageous for the performance on snow.

According to the present invention, by providing a concave portion in the edge portion, the deformation of the edge portion is increased, the edge penetrates the snow more, the edge effect is improved, and the performance on snow is improved.

Furthermore, by not sacrificing the groove volume (the groove volume is increased by providing the concave portion), the shear strength of the snow column can be sufficiently maintained, and the performance on snow can be improved even when dealing with fresh snow, coarse snow, and medium-pressure snow. can do.

Also, in the present invention, the deformation is increased by providing a concave portion at the edge portion, the penetration into the snow is increased, the edge effect is improved, and the performance on snow is improved. As long as there is a recess, the performance on snow is improved.

Further, even if the recess is worn out completely, the performance is not deteriorated (the same as when there is no recess).

According to a second aspect of the present invention, in the pneumatic tire according to the first aspect, at least a part of the edge on the stepping side of the block-shaped land portion is provided with the concave portion. And

Next, the operation of the pneumatic tire according to claim 2 will be described.

By providing the concave portion on the stepping side of the block-shaped land portion, the side where the block-shaped land portion first comes into contact with the road surface, that is, the stepped side of the block-shaped land portion can easily bite into the snow surface (ie, the edge). Effect is enhanced), and traction performance on snow is improved.

According to a third aspect of the present invention, in the pneumatic tire according to the second aspect, the concave portion provided on the stepped-side edge of the block-shaped land portion is provided in the edge of the stepped-side edge. It is characterized in that it is provided near the stepping end.

Next, the operation of the pneumatic tire according to claim 3 will be described.

When the block-shaped land portion is stepped on, the portion that first comes into contact with the snow surface is the stepped end. Therefore, by providing a concave portion near the stepped end, the block-shaped land portion can be effectively cut into the snow surface. Can be.

According to a fourth aspect of the present invention, in the pneumatic tire according to the second or third aspect, the concave portion provided on the edge on the stepping side of the block-shaped land portion is provided with the recess on the stepping side. The edge is provided over a length of 30% or more of the entire length of the edge.

Next, the operation of the pneumatic tire according to the fourth aspect will be described.

In the case where the concave portion provided on the step-side edge of the block-shaped land portion is not provided over 30% or more of the entire length of the step-side edge, the block-shaped land portion with respect to the snow surface is not provided. The amount of bite may be insufficient, and the effect of improving traction performance on snow may be insufficient. Therefore, the concave portion provided on the stepping-side edge of the block-shaped land portion is set to be 3% of the total length of the stepping-side edge.
It is preferable to provide over 0% or more of the length.

The length of the concave portion provided on the stepping-side edge is preferably 50% of the length of the stepping-side edge.
More preferably, the length is not less than the above.

According to a fifth aspect of the present invention, there is provided the pneumatic tire according to any one of the first to fourth aspects, wherein:
The concave portion is provided on at least a part of the edge on the kick-out side of the block-shaped land portion.

Next, the operation of the pneumatic tire according to claim 5 will be described.

Since the concave portion is provided on the kick-out side of the block-shaped land portion, that is, the front edge of the block-shaped land portion that is in contact with the snow surface, the block-shaped land portion is easily digged into the snow surface, and the snow-covered brake is provided. Performance is improved.

According to a sixth aspect of the present invention, in the pneumatic tire according to the fifth aspect, the concave portion provided at the edge of the block-shaped land portion on the kick-out side is formed with the edge on the kick-out side. It is characterized by being provided near the kick-out end inside.

Next, the operation of the pneumatic tire according to claim 6 will be described.

At the time of braking, the foremost end of the block-shaped land portion in contact with the snow surface is the kicking end. Therefore, by providing a concave portion near the kicking end, the block-shaped land portion is effectively cut into the snow surface. Can be made.

According to a seventh aspect of the present invention, in the pneumatic tire according to the fifth or sixth aspect, the concave portion provided at the edge of the block-shaped land portion on the kick-out side is provided on the kick-out side. The edge is provided over 30% or more of the entire length of the edge.

Next, the operation of the pneumatic tire according to claim 7 will be described.

If the concave portion provided on the kick-out side edge of the block-like land portion is not provided over 30% or more of the entire length of the kick-side edge, the snow of the block-like land portion may be removed. The amount of bite into the surface may be insufficient, and the effect of improving snow braking performance may be insufficient. Therefore, the concave portion provided on the kick-out side edge of the block-shaped land portion is set to 30% of the total length of the kick-out side edge.
%.

The length of the concave portion provided on the edge on the kicking side is preferably 50% of the length of the edge on the kicking side.
More preferably, the length is not less than the above.

The invention according to claim 8 provides the pneumatic tire according to any one of claims 1 to 7,
The concave portion is provided on at least a part of the edge on the tire axial direction side of the block-shaped land portion.

Next, the operation of the pneumatic tire according to claim 8 will be described.

Since at least a part of the edge on the tire axial direction side of the block-shaped land portion is provided with a concave portion, when the pneumatic tire attempts to move on the snow surface in the tire axial direction, the tire of the block-shaped land portion has Since the axial direction side is more likely to bite into the snow surface and the movement (slip) of the pneumatic tire in the axial direction of the tire is suppressed, steering stability on snowy roads can be improved.

According to a ninth aspect of the present invention, in the pneumatic tire according to the eighth aspect, the concave portion provided at the edge of the block-shaped land portion on the tire axial direction side is provided on the tire axial direction side. It is characterized in that it is provided near the end in the tire axial direction among the edges.

Next, the operation of the pneumatic tire according to the ninth aspect will be described.

When the pneumatic tire attempts to move in the tire axial direction, the portion of the block-shaped land portion closest to the tire axial direction is the tire axial end. By providing it near the end in the axial direction, the block-shaped land can be effectively cut into the snow surface.

According to a tenth aspect of the present invention, in the pneumatic tire according to the eighth or ninth aspect, the concave portion provided at the edge of the block-shaped land portion in the tire axial direction includes the tire shaft. It is characterized in that it is provided over a length of 30% or more of the entire length of the edge on the direction side.

Next, the operation of the pneumatic tire according to the tenth aspect will be described.

In the case where the concave portion provided in the tire axial direction edge of the block-shaped land portion is not provided over 30% or more of the entire length of the tire axial direction edge,
In some cases, the amount of the block-shaped land portion biting into the snow surface may be insufficient, and the effect of improving the steering stability on snow may be insufficient. Therefore, it is preferable that the concave portion provided on the tire axial direction edge of the block-shaped land portion is provided over 30% or more of the entire length of the tire axial direction edge.

The length of the concave portion provided on the edge on the tire axial direction side is more preferably 50% or more of the length of the edge on the tire axial direction side.

According to an eleventh aspect of the present invention, in the pneumatic tire according to any one of the first to tenth aspects, the block-shaped land portion is formed such that a radially inner portion of the bottom portion in the tire radial direction is the same as that of the pneumatic tire. It is characterized by projecting to the main groove side.

Next, the operation of the pneumatic tire according to the eleventh aspect will be described.

By protruding the inner portion in the tire radial direction of the bottom toward the main groove, the rigidity of the inner portion in the tire radial direction is higher than that of the bottom of the concave portion, and the rigidity of the block-shaped land portion on the land tread side and the base portion side are improved. The rigidity and the rigidity difference are increased, and the block-shaped land portion is more likely to bite into the snow surface.

This is because the radially inner portion of the bottom portion in the tire radial direction is extended toward the main groove, so that the rigidity of the block root portion is increased and the deformation amount of this portion is reduced. As a result, the deformation concentrates on the block tip (tread side), the vicinity of the edge of the block tip (tread side) is more inclined, and it easily penetrates the snow surface, so that the on-snow performance is improved.

According to a twelfth aspect of the present invention, in the pneumatic tire according to the eleventh aspect, the amount of protrusion of the bottom portion in the tire radial direction toward the main groove is determined by the amount of the main groove facing the bottom. The groove width is not more than 30% of the groove width.

Next, the operation of the pneumatic tire according to claim 12 will be described.

The amount of protrusion of the bottom portion in the tire radially inner portion (step portion) toward the main groove is 3 times the groove width of the main groove facing the bottom.
If it exceeds 0%, the groove volume of the main groove is reduced, the drainage performance is reduced, and the wet performance may be reduced. Therefore, it is preferable that the amount of protrusion of the bottom portion in the radial direction inside the tire toward the main groove be 30% or less of the groove width of the main groove facing the bottom.

According to a thirteenth aspect of the present invention, in the pneumatic tire according to any one of the first to twelfth aspects, the depth dimension from the tread surface to the bottom portion of the pneumatic tire is equal to the depth of the main groove. The groove depth is not less than 25% and not more than 58%.

Next, the operation of the pneumatic tire according to claim 13 will be described.

If the depth dimension from the land tread to the bottom is less than 25% of the groove depth of the main groove, the bottom will appear on the land tread at an early stage of wear, and then the block-shaped land is removed from the snow. This makes it difficult to cut into the surface, making it impossible to improve the performance on snow.

On the other hand, when the depth dimension from the land tread to the bottom exceeds 58% of the groove depth of the main groove, the rigidity of the block-shaped land portion is excessively reduced and deformation (falling) becomes unnecessarily large. As a result, it becomes difficult for the block-shaped land portion to bite into the snow surface, and the performance on snow cannot be improved.

Therefore, it is preferable that the depth from the tread of the land portion to the bottom is 25% or more and 58% or less of the groove depth of the main groove.

It is more preferable that the depth from the tread surface of the land portion to the bottom is 33% or more and 50% or less. This is because if it is 33% or more, it is possible to prevent a decrease in performance after wear from an appropriate time, and if it is 33% or more and 50% or less, the performance on snow is reduced from the initial wear to the middle wear stage. Can be prevented.

According to a fourteenth aspect of the present invention, in the pneumatic tire according to any one of the first to thirteenth aspects, the concave portion surrounds a peripheral edge of a block end composed of two edges. The angle of the block end may be an obtuse angle of 90 ° or more.

Next, the operation of the pneumatic tire according to claim 14 will be described.

As shown in FIGS. 15A and 15B, when the concave portion 102 surrounds the periphery of the block edge composed of two edges, the angle θ of the block edge is 90 ° as shown in FIG. 15A. If the angle is less than 10 mm, the rigidity in the vicinity of the end of the block will be too low, and the end of the block will not easily penetrate the snow surface.

According to a fifteenth aspect of the present invention, in the pneumatic tire according to any one of the first to fourteenth aspects, the width of the recess is 0.5 mm or more and 3 mm or less. I have.

Next, the operation of the pneumatic tire according to claim 14 will be described.

When the width of the concave portion is less than 0.5 mm, the function provided by the concave portion cannot be obtained.

On the other hand, if the width of the concave portion exceeds 3 mm, the contact area of the tread of the land portion decreases, and there is a possibility that the performance on ice may be reduced.

Therefore, the width of the concave portion should be 0.5 mm or more and 3 mm or more.
By doing as follows, the amount of penetration of the block-shaped land portion into the snow surface can be effectively improved without significantly reducing the contact area of the block-shaped land portion.

It is more preferable that the width of the recess is 1 mm or more and 2 mm or less.

According to a sixteenth aspect of the present invention, in the pneumatic tire according to any one of the first to fifteenth aspects, the bottom is not parallel to the land surface. .

Next, the operation of the pneumatic tire according to claim 16 will be described.

If the bottom of the recess is provided so as not to be parallel to the tread of the land, that is, if the bottom is gradually inclined, the bottom will be gradually exposed at the time of abrasion, and a rapid change in the performance on snow and the performance on ice will be prevented. Can be suppressed.

According to a seventeenth aspect of the present invention, in the pneumatic tire according to the sixteenth aspect, the bottom is inclined at an angle θ with respect to a normal to the land tread. It is characterized by being at most 45 °.

Next, the operation of the pneumatic tire according to claim 17 will be described.

It is preferable that the angle θ of the bottom with respect to the normal line formed on the land tread be 45 ° or less, since the performance on snow and the performance on ice can be gradually changed.

The angle θ is preferably 30 ° or less, whereby the performance on snow and the performance on ice when the bottom is exposed during wear can be changed more gently.

The invention according to claim 18 is the pneumatic tire according to any one of claims 1 to 17, wherein a sipe is formed in the block-like land portion. I have.

Next, the operation of the pneumatic tire according to claim 18 will be described.

By providing a sipe provided in a general winter tire on the block-shaped land portion, the edge effect of the sipe is increased, so that the performance on snow can be further improved, and the performance on ice can also be improved. .

Here, in the present invention, the kick-out side of the block-shaped land portion is a side surface of the block-shaped land portion that can be seen from the rear in the rotation direction.

The stepping side of the block-shaped land portion is as follows.
This is a side view of the block-shaped land portion viewed from the front in the rotation direction.

Further, the lateral side of the block-shaped land portion is a side surface of the block-shaped land portion viewed from the tire lateral direction.

The side surface that can be seen from both the rearward and lateral directions in the rotational direction is the stepping side and the lateral side, and the lateral surface that can be seen from both the forward direction and the lateral direction in the rotational direction is the kick side and the lateral side. is there.

[0095]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] Next, a first embodiment of the pneumatic tire of the present invention will be described with reference to FIGS.

As shown in FIG. 2, the tread 12 of the pneumatic tire 10 of the present invention has a plurality of circumferential grooves 14 extending in the tire circumferential direction (the directions of arrows A and B).
And a plurality of block-shaped land portions 18 divided by a plurality of lateral grooves 16 extending along the tire axial direction (the direction of the arrow L and the direction of the arrow R).

As shown in FIG. 2, the shape of the block-shaped land portion 18 of the present embodiment is a point-symmetric shape, that is, when it is rotated by 180 ° about the intersection P of two diagonal lines, the original position before rotation is obtained. The shape matches the shape.

Since the internal structure of the pneumatic tire 10 is the same as that of a general radial tire, description of the internal structure is omitted.

As shown in FIGS. 1 and 3, the block-shaped land portion 18 has a bottom portion 20 which is higher than the groove bottoms of the circumferential grooves 14 and the lateral grooves 16 and lower than the tread surface 19 of the block-shaped land portion 18.
The depression 20 having an A is a stepping side (a side that first comes into contact with the road surface when the vehicle is traveling forward. In this embodiment, the tire rotates in the direction of the arrow A when the vehicle is traveling forward, so that the tire is in the direction of the arrow A) and kicks out. Side (the side opposite to the stepping side; the side in the direction of arrow B) is formed at the edge of the land side surface (groove wall) and the land tread surface.

Note that the depression 20 on the stepping side and the depression 20 on the kicking side are point-symmetrical (in this embodiment, a line L parallel to the tire axial direction passing through the central portion in the tire circumferential direction of the block-shaped land portion 18). Is also symmetrical with respect to.).

As shown in FIG. 1, a bottom 20A of the recess 20 is formed.
Is preferably not parallel to the tread surface 19 of the block-shaped land portion 18, and is preferably inclined at an angle θ1 with respect to a normal HL standing on the tread surface 19 so as to become lower as the distance from the block-shaped land portion 18 increases. . Angle θ1 is 45 °
Or less, more preferably 30 ° or less. The angle θ1 of the bottom 20A of the present embodiment is 45 °. The angle θ1 takes an average value when the bottom 20A is a curve.

The depth D1 of the bottom 20A measured from the tread 19 along the groove depth direction (when the bottom 20A is inclined, the dimension from the tread 19 to the uppermost end of the bottom 20A) is the recess 20. Is preferably 25% or more and 58% or less of the groove depth D4 of the lateral groove 16 in this embodiment.

The width W2 of the concave portion 20 is preferably 0.5 mm or more and 3 mm or less, more preferably 1 mm or more and 2 mm or less.

The pneumatic tire 10 of this embodiment has a tire size of 195 / 65R15.

As shown in FIG. 4, the dimensions of the block land portion 18 of the present embodiment are such that the tire circumferential length L1 is 35 mm,
The width W1 in the tire axial direction is 25 mm.

As shown in FIGS. 1 and 3, in the embodiment, the groove depth D3 of the circumferential groove 14 is 12 mm, the groove depth D4 of the lateral groove 16 is 12 mm, the groove width W3 of the circumferential groove 14 is 8 mm, The width W4 of the lateral groove 16 is 10 mm, and the depth D1 of the bottom 20A is 4 m.
m (33% of the groove width W4 of the lateral groove 16), the width W2 of the concave portion 20
Is 1 mm. (Operation) Next, the operation of the pneumatic tire 10 of the present embodiment will be described.

In this pneumatic tire 10, since the concave portion 20 is formed over the entire length of the stepping side edge and the kicking side edge of the block-shaped land portion 18, the block-shaped land portion 18 is formed by braking or driving. When deformed, the portion near the groove bottom has a large land portion volume, so the rigidity is high and the deformation (tilt) is small, and the portion near the tread 19 is small in the land portion volume, so the rigidity is low and the concave portion 20 is formed. Deformation is greater than in the case where it is not performed.

For this reason, at the time of driving, as shown in FIG.
Can penetrate deeply into the snow surface of the snowy road 22 and the traction performance on snow can be improved.

Further, at the time of braking, the edge on the kick-out side can penetrate deeply into the snow surface, so that the braking performance on snow can be improved.

Further, according to the pneumatic tire 10 of the present embodiment, since the concave portion 20 is formed in the block-shaped land portion 18 and the groove volume is not reduced, the snow column shear force is not reduced. In addition, there is no possibility that the performance on snow in fresh snow, rough snow, or medium-pressure snow is reduced, and there is no possibility that the wet performance is reduced.

In traveling on high-pressure snow near an ice floe, the edge effect (the effect generated when the edge portion penetrates the snow and scratches the snow) contributes more than the snow column shearing force.
In order to improve the edge effect, the deformation (inclination) of the edge portion may be increased as compared with the related art so that the edge portion penetrates the snow.

In the present embodiment, since the concave portion 20 is formed in the block-shaped land portion 18, the edge portion is greatly deformed, the edge effect is improved, and the performance on snow can be improved.

In this embodiment, the recess 2 is formed at the edge.
By providing 0, the deformation is increased, the penetration into the snow is increased, the edge effect is improved, and the performance on snow is improved,
Even if the pneumatic bias tire 10 is worn, the performance on snow is improved as long as the recess 20 exists.

Even if the recess 20 is completely worn out, the performance is not deteriorated (the same as when there is no recess 20).

In the pneumatic tire 10, the recesses 20 are formed on both sides of the block-shaped land portion 18 in the tire circumferential direction.
Because there is no directionality of mounting.

Further, in the pneumatic tire 10 of the present embodiment, the bottom 20A of the recess 20 is inclined, so that when the bottom 20A is exposed on the tread 19 due to wear of the tread 12, the bottom 20A gradually comes into contact with the tread 19. As a result, a sudden change in performance on snow and performance on ice can be suppressed.

Here, if the width W2 of the concave portion 20 is less than 0.5 mm, the effect of providing the concave portion 20 cannot be obtained. On the other hand, if the width W2 of the concave portion 20 exceeds 3 mm, the contact area of the tread 19 is reduced, and the performance on ice may be reduced.

If the depth dimension D1 of the bottom portion 20A is less than 25% of the groove depth D4 of the lateral groove 16, the bottom portion 20A will be initially worn.
Appears on the tread 19, and thereafter, the performance on snow cannot be improved. On the other hand, if the depth dimension D1 of the bottom portion 20A exceeds 58% of the groove depth D4 of the lateral groove 16, the performance on snow cannot be similarly improved.

Note that the concave portions 2 are formed in all the block land portions 18.
Although it is not necessary to provide 0, as in this embodiment, when the block-shaped land portion 18 includes a block row arranged in the tire circumferential direction, all the block-shaped land portions in all rows are required to improve the performance on snow. Preferably, a recess 20 is provided in 18.

In this embodiment, the block-shaped land portion 1 is used.
8 is rectangular, but the present invention is not limited to this, and the shape of the block-shaped land portion 18 may be a trapezoid as shown in FIG. 6 (A). As shown in (C), the shape may be a rhombus, and other well-known shapes such as a polygon and an ellipse may be used although not shown.
However, the concave portion 20 is point-symmetric (see FIG. 6B) or line-symmetric (FIGS. 6A and 6C) on the stepping side and the kicking side.
).

The block-shaped land portion 18 includes, for example,
As shown in FIG. 7, a sipe 24 extending along the tire axial direction may be provided. The performance on snow can be further improved by the edge effect of the sipe 24, and the performance on ice can also be improved.

In this embodiment, the block-like land portion 1
Although the concave portion 20 is provided over the entire length of the stepping-side edge and the kick-out side edge of No. 8, the present invention is not limited to this, and may be provided at least in part of the entire length of the edge. .

In order to surely improve the performance on snow,
As shown in FIG. 8, the length L2 of the recess 20 is preferably 30% or more of the entire length L1 of the edge, and more preferably 50% or more. Second Embodiment Next, a pneumatic tire 30 according to a second embodiment of the present invention will be described with reference to FIGS. The same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 9, the pneumatic tire 3
Tread 1 of 0 (tire size: 195 / 65R15)
2 includes a circumferential main groove 3 provided on the tire equatorial plane CL.
2. A curved inclined groove 34 extending from the circumferential main groove 32 toward the shoulder side, and a first inclined groove 36 and a second inclined groove 38 connecting the curved inclined grooves 34 adjacent to each other in the tire circumferential direction. First block 40, second
And a third block 44 of
These plural types of blocks form a block pattern which is symmetrical with respect to the tire equatorial plane CL.

The angle of the curved inclined groove 34 with respect to the tire circumferential direction gradually increases from the tire equatorial plane CL side to the shoulder side. The angle of the first inclined groove 36 with respect to the tire circumferential direction is set to be larger than the angle of the second inclined groove 38 with respect to the tire circumferential direction.

First block 40, second block 42
The third block 44 is arranged along the tire circumferential direction.

The mounting direction of the pneumatic tire 30 is specified when the vehicle is mounted, and the rotation direction of the pneumatic tire 30 when the vehicle is moving forward is in the direction of arrow A. That is, the pneumatic tire 3
At 0, the side of the first block 40, the second block 42, and the third block 44 in the direction of arrow A is the stepping side (the side of arrow B is the kicking side).

As shown in FIGS. 9 and 10A, the first
In the block 40, a concave portion 46 is partially provided at the edge facing the curved inclined groove 34 on the stepping side.

As shown in FIGS. 9 and 10B, the second
In the block 42, a concave portion 48 is partially provided on each of the edge facing the curved inclined groove 34 on the stepping side and the edge facing the first inclined groove 36.

As shown in FIG. 9 and FIG.
In the block 44, a concave portion 50 is partially provided on each of the edge facing the curved inclined groove 34 on the stepping side and the edge facing the second inclined groove 38.

The width, bottom depth, bottom angle, and the like of the recesses 46, 48, and 50 are specified in the recess 20 of the first embodiment.
Is the same as

In the pneumatic tire 30 of the present embodiment, a recess 46 is provided on the stepping side of the first block 40,
Since the concave portion 48 is provided on the stepping side of the block 42 and the concave portion 50 is provided on the stepping side of the third block 44, similarly to the first embodiment, the edge of the stepping It is easy to cut into the surface, and traction performance on snow is improved.

According to the pneumatic tire 30 of the present embodiment, the concave portion 46 is provided on the stepping side of the first block 40, the concave portion 48 is provided on the stepping side of the second block 42, and the third block 44 is provided. A concave portion 50 is provided on the stepping side of the tire, and the groove volume is not reduced as in the first embodiment, so that the snow column shear force is not reduced, and the performance on snow in fresh snow, coarse snow, and medium-pressure snow is improved. There is no danger of lowering and there is no danger of lowering wet performance.

The traction performance in high-pressure snow near an ice plate has a greater contribution of the edge effect than the snow column shearing force because the snow quality is hard.

In addition, the traction at the time of starting has a large slip ratio, so that it is difficult to form a snow column, and the contribution of the edge effect is larger than the snow column shearing force.

In order to improve the edge effect, the deformation (inclination) of the edge portion may be made larger than in the prior art so as to penetrate the snow more.

In this embodiment, since the concave portion is formed on the stepping side of each block, the edge portion is greatly deformed, the edge effect is improved, and the performance on snow can be improved.

Further, in the present embodiment, the concave portion is provided at the edge portion to increase the deformation, increase the penetration into the snow, improve the edge effect, and improve the performance on snow. Even if worn, the performance on snow is improved as long as there are recesses.

Even if the recess is completely eliminated, the performance is not deteriorated (the same as when there is no recess).

Note that a sipe may be provided in each of the first block 40, the second block 42, and the third block 44. Thereby, the traction performance on snow and the performance on ice can be further improved. [Third Embodiment] Next, a pneumatic tire 60 according to a third embodiment of the present invention will be described with reference to FIG.
The same components as those of the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 11, the tread 12 of the pneumatic tire 60 has the same block pattern as the pneumatic tire 30 of the second embodiment.

The mounting direction of the pneumatic tire 60 is the same as that of the pneumatic tire 30 of the second embodiment.
The side of the block 40, the second block 42 and the third block 44 in the direction of arrow A is the stepping side (the side of arrow B is the kicking side).

In the first block 40, a concave portion 62 is provided at the edge facing the curved inclined groove 34 on the kick-out side.

The second block 42 is provided with a recess 64 at the edge facing the curved inclined groove 34 on the kick-out side.

In the third block 44, a concave portion 66 is provided on the edge facing the curved inclined groove 34 on the kick-out side.

The width, bottom depth, bottom angle, etc. of the recesses 62, 64, 66 are the same as those of the recesses 46, 48, 50.

In the pneumatic tire 60 of the present embodiment, a concave portion 62 is provided on the kick-out side of the first block 40,
Since the concave portion 64 is provided on the kicking side of the block 42 and the concave portion 66 is provided on the kicking side of the third block 44, the kicked end is more likely to bite into the snow surface during braking, and the snow braking performance is improved.

According to the pneumatic tire 60 of the present embodiment, the concave portion 62 is provided on the kick-out side of the first block 40, and the concave portion 64 is provided on the kick-out side of the second block 42. A concave portion 66 is provided on the kick-out side of the block 44, and the groove volume is not reduced as in the first embodiment, so that the snow column shearing force is not reduced, and fresh snow, coarse snow, and medium-pressure snow can be used. There is no danger of lowering the performance on snow, and there is no danger of lowering the wet performance.

In the braking performance in high-pressure snow close to an ice plate, the edge effect contributes more than the snow column shearing force because the snow quality is hard.

In order to improve the edge effect, the deformation (inclination) of the edge portion may be increased as compared with the conventional case, and the snow may penetrate more.

In this embodiment, since the concave portion is formed on the kick-out side of each block, the edge portion is greatly deformed, the edge effect is improved, and the performance on snow can be improved.

In this embodiment, the concave portion is provided at the edge to increase the deformation, increase the penetration into the snow, improve the edge effect, and improve the on-snow performance. Even if worn, the performance on snow is improved as long as there are recesses.

Even if the recess is completely eliminated, the performance is not deteriorated (the same as when there is no recess).

Note that a sipe may be provided in each of the first block 40, the second block 42, and the third block 44. Thereby, the on-snow braking performance and the on-ice performance can be further improved. [Fourth Embodiment] Next, a pneumatic tire 70 according to a fourth embodiment of the present invention will be described with reference to FIG.
The same components as those of the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 12, the pneumatic tire 70 has the first block 40, the second block 42, and the third block 44 provided with recesses on both the stepping side and the kicking side. is there.

Therefore, both the traction performance on snow and the braking performance on snow can be improved.

Note that, similarly to the above-described embodiment, a sipe may be provided in each of the first block 40, the second block 42, and the third block 44. [Fifth Embodiment] Next, a pneumatic tire 80 according to a fifth embodiment of the present invention will be described with reference to FIG.
The same components as those of the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

This pneumatic tire 80 is a modified example of the pneumatic tire 30 of the second embodiment, and as shown in FIG. Of the bottom portion 48A of the block 42 in the tire radial direction, and the bottom portion 50A of the third block 44.
Of the tire radially inwardly protrude toward the groove side by a predetermined dimension.

Here, assuming that the amount of protrusion of the bottom toward the groove side with respect to the block side surface (portion where no concave portion is provided) is S, S is 30% of the groove width of the main groove facing the concave portion. % Is preferable.

As described above, the lower portion in the tire radial direction of each bottom portion is extended to the groove side by a predetermined size, whereby the rigidity near the groove bottom of each block, that is, near the base portion is increased, and this portion is hardly deformed. Since the vicinity of the edge is easily deformed, the edge easily penetrates the snow, and the edge effect is improved. In the present embodiment, the traction performance on snow can be further improved.

Here, when the projection amount S exceeds 30% of the groove width of the main groove facing the concave portion, the groove volume may be reduced and wet performance may be reduced.

In the concave portion on the kick-out side of the block, the inner portion in the tire radial direction at the bottom may be protruded toward the groove. Thereby, the braking performance on snow can be further improved. (Test Example 1) In order to confirm the effects of the present invention, seven kinds of tires of a comparative example having a directional pattern and twelve kinds of tires of an example to which the present invention was applied were prepared, and the traction performance on snow and the brake on snow were prepared. Tests were conducted on the performance and handling stability on snow.

The rim and internal pressure are based on the applicable rim and air pressure-load capacity correspondence table corresponding to the size of the radial ply tire specified by JATMA YEAR BOOK (2000 edition of the Japan Automobile Tire Association Standard).

The tire size of the prototype tire was 195 /
65R15, and the pattern is the directional pattern shown in FIG.

The presence / absence of a recess in the prototype tire and the length of the recess /
Edge length, bottom depth (mm), recess overhang (30% of groove width), recess width (mm), sipes (lateral sipes)
Is as shown in the following Tables 2 to 16 (see Table 1 for the position of the edge). Traction performance on snow: The test tire was assembled on a rim of 6J-15 at an internal pressure of 200 kPa, mounted on a passenger car, and evaluated on the time (acceleration time) until the accelerator was fully opened from a stationary state on a snowy road and traveled 50 m (acceleration time).

The evaluation is as described in Table 17 below. Tires without sipe (Comparative Example 1 and Example 1) are compared with Comparative Example 1 as 100, and tires with sipe (Comparative Example 2) In Examples 7 to 12), the reciprocal of the acceleration time of the new tire of Comparative Example 2 is set to 100, and the larger the value, the better the traction performance on snow.・ Snow braking performance: The test tire was mounted on a 6J-15 rim at an internal pressure of 200 kPa and mounted on a passenger car at a speed of 4
Evaluation was made based on the braking distance when braking was performed from 0 km / h.

The evaluation was also as described in Table 17 below. Tires without sipe (Comparative Example 1 and Example 1) were compared with Comparative Example 1 as 100, and tires with sipe (Comparative Example 1) were used. 2 to 7 and Examples 2 to 12), the reciprocal of the braking distance of the new tire of Comparative Example 2 is represented by an index of 100, and the larger the value, the better the snow braking performance. -Snow handling stability: The test tires were mounted on a 6J-15 rim at an internal pressure of 200 kPa and mounted on a passenger car, and the test driver was evaluated by running on a snow test course. The evaluation is a feeling evaluation. In the tire without sipe (Comparative Example 1 and Example 1), the new tire of Comparative Example 1 was set to ± 0, and the tire with sipe (Comparative Examples 2 to 7,
In Examples 2 to 12), the evaluation criteria are as follows, with the new tire of Comparative Example 2 being ± 0. +5: extremely good +4: +3: good (most general drivers can be understood) +2: +1: slightly good (test drivers can be understood) ± 0: standard (tire of Comparative Example 1 or 2) -1: slightly bad ( -2: -3: Bad (most general drivers can be found) -4: -5: Extremely bad The snowy road surface used in the test was high-pressure snow close to an ice floe. Hardness is 10kg / m as measured by Kinoshita photometer
² (For Kinoshita hardness tester, "Basic Snow and Ice Course I"
Structure and Physics of Snow and Ice ", written by Kiichi Maeno and Toshio Kuroda, Shokan Shoin. ).

The “ratio% of the concave portion to the target side edge” in the table is the edge length (the length of the edge in the tire rotation axis direction) when the target side edge is projected on a line parallel to the tire rotation axis. The length of the concave portion (the length component of the concave portion in the tire rotational axis direction) when the concave portion provided at the edge on the target side is projected on a line parallel to the tire rotation axis. It is.

[0169]

[Table 1]

[0170]

[Table 2]

[0171]

[Table 3]

[0172]

[Table 4]

[0173]

[Table 5]

[0174]

[Table 6]

[0175]

[Table 7]

[0176]

[Table 8]

[0177]

[Table 9]

[0178]

[Table 10]

[0179]

[Table 11]

[0180]

[Table 12]

[0181]

[Table 13]

[0182]

[Table 14]

[0183]

[Table 15]

[0184]

[Table 16]

[0185]

[Table 17]

(Test Example 2) In order to confirm the effect of the present invention, seven kinds of tires of a comparative example having a pattern without directionality and ten kinds of tires of an example to which the present invention was applied were prepared.
Tests were performed on snow traction performance, snow braking performance, and snow handling stability performance.

The test method and the evaluation method are the same as in Test Example 1.

The tire size of the prototype tire was 195 /
65R15, and the pattern is a pattern without directivity shown in FIG.

The presence / absence of a recess in the prototype tire and the length of the recess /
Edge length, bottom depth (mm), recess overhang (30% of groove width), recess width (mm), sipes (lateral sipes)
The presence or absence of is as shown in Tables 19 to 23 below (see Table 18 for the position of the edge). The depth of each groove is 12 mm.

[0190]

[Table 18]

[0191]

[Table 19]

[0192]

[Table 20]

[0193]

[Table 21]

[0194]

[Table 22]

[0195]

[Table 23]

[0196]

As described above, the pneumatic tire according to the first aspect has the above-described configuration, and thus has an excellent effect that the performance on snow can be improved without deteriorating the performance on ice. .

Since the pneumatic tire according to the second aspect has the above-described structure, it has an excellent effect that traction performance on snow can be improved.

Since the pneumatic tire according to the third aspect has the above-described structure, it has an excellent effect that the stepping side of the block-shaped land portion can be effectively cut into the snow surface.

Since the pneumatic tire according to the fourth aspect has the above-described structure, the pneumatic tire has an excellent effect that the stepping side of the block-shaped land portion can be reliably cut into the snow surface.

Since the pneumatic tire according to the fifth aspect has the above-described configuration, it has an excellent effect that the braking performance on snow can be improved.

Since the pneumatic tire according to claim 6 is configured as described above, the kick-out side of the block-shaped land portion can be effectively cut into the snow surface.

[0202] The pneumatic tire according to claim 7 has the above-described configuration, and thus has an excellent effect that the kick-out side of the block-shaped land portion can be reliably cut into the snow surface.

[0203] The pneumatic tire according to the eighth aspect is configured as described above, so that the movement (slip) of the pneumatic tire in the tire axial direction can be suppressed, and the steering stability on snowy roads can be improved. It has an excellent effect.

The pneumatic tire according to the ninth aspect has the excellent effect that the axial direction side of the block-shaped land portion can be effectively cut into the snow surface because of the above configuration.

Since the pneumatic tire according to the tenth aspect has the above-described configuration, it has an excellent effect that the steering stability on snow can be reliably improved.

Since the pneumatic tire according to the eleventh aspect has the above-described configuration, it has an excellent effect that the block-shaped land portion is more likely to bite into the snow surface.

Since the pneumatic tire according to the twelfth aspect has the above-described structure, the pneumatic tire has an excellent effect that the block-shaped land portion is more likely to bite into the snow surface without deteriorating the wet performance.

The pneumatic tire according to the thirteenth aspect has the above-described configuration, and thus has an excellent effect that the performance on snow can be prevented from being reduced from the initial wear stage to the middle wear stage.

[0209] The pneumatic tire according to the fourteenth aspect has the above-described configuration, and thus has an excellent effect that a decrease in the amount of bite into the snow surface at the block end can be suppressed.

[0210] The pneumatic tire according to the fifteenth aspect is configured as described above, so that the amount of the block-like land portion penetrating into the snow surface can be effectively improved without deteriorating the performance on ice, and It has an excellent effect that the performance can be surely improved.

[0211] The pneumatic tire according to claim 16 is configured as described above, so that a sudden change in the performance on snow and the performance on ice when the bottom is exposed to the tread surface on the land can be suppressed.
It has an excellent effect. .

Since the pneumatic tire according to the seventeenth aspect has the above-described structure, it has an excellent effect that the performance on snow and the performance on ice can be gradually changed.

[0213] The pneumatic tire according to the eighteenth aspect has the above-described configuration, and thus has an excellent effect that the performance on snow can be further improved and the performance on ice can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view (cross-section along the tire circumferential direction) of a block-shaped land portion of a pneumatic tire according to a first embodiment of the present invention.

FIG. 2 is a plan view of a tread of the pneumatic tire according to the first embodiment of the present invention.

FIG. 3 is a side view of the block-shaped land portion of the pneumatic tire according to the first embodiment of the present invention as viewed from the tire circumferential direction.

FIG. 4 is an enlarged plan view of a block-shaped land portion.

FIG. 5 is a side view of the block-shaped land portion as viewed from the tire axial direction when stepping on a snow surface.

FIGS. 6A to 6C are enlarged plan views of a block-like land portion of a pneumatic tire according to another embodiment.

FIG. 7 is a plan view of a block-shaped land portion provided with a sipe.

FIG. 8 is a plan view of a block-shaped land portion showing a relationship between the length of an edge and the length of a concave portion.

FIG. 9 is a plan view of a tread of a pneumatic tire according to a second embodiment of the present invention.

10A is a perspective view of a first block shown in FIG. 9, FIG. 10B is a perspective view of a second block shown in FIG. 9, and FIG. 10C is a third view shown in FIG. It is a perspective view of the block of FIG.

FIG. 11 is a plan view of a tread of a pneumatic tire according to a third embodiment of the present invention.

FIG. 12 is a plan view of a tread of a pneumatic tire according to a fourth embodiment of the present invention.

FIG. 13A is a plan view of first to third blocks of a pneumatic tire according to a fifth embodiment of the present invention, and FIG. 13B is a plan view of the first to third blocks shown in FIG. It is a perspective view of the block of FIG.

14A is a perspective view of a block-shaped land portion having no concave portion, and FIG. 14B is a side view showing deformation of the block-shaped land portion shown in FIG. , (C)
Is a perspective view of a block-shaped land portion provided with a concave portion,
FIG. 15D is a side view showing deformation of the block-like land portion shown in FIG.

FIG. 15A is a plan view of a block-shaped land portion having a concave portion formed at an acute block end, and FIG. 15B is a plan view of a block-shaped land portion having a concave portion formed at an obtuse block end. is there.

[Explanation of symbols]

 Reference Signs List 10 Pneumatic tire 12 Tread 14 Circumferential groove (main groove) 18 Block-shaped land portion 19 Tread surface 20 Depression 20A Bottom part 24 Sipe 30 Pneumatic tire 34 Curved inclined groove (main groove) 36 First inclined groove (main groove) 38 Second inclined groove (main groove) 40 First block (block-shaped land portion) 42 Second block (block-shaped land portion) 44 Third block (block-shaped land portion) 46 Recess 46A Bottom 48 Recess 48A Bottom 50 concave portion 50A bottom 60 pneumatic tire 62 concave portion 64 concave portion 66 concave portion 70 pneumatic tire

Claims (18)

[Claims] 1. A pneumatic tire having a plurality of block-shaped land portions divided by a plurality of main grooves crossing each other on a tread, wherein the block-shaped land portions include a land tread surface, a land side surface, A pneumatic tire is provided with a recess having a bottom portion higher than the groove bottom of the main groove and lower than the land portion tread surface at an edge of the pneumatic tire. 2. The pneumatic tire according to claim 1, wherein the recess is provided in at least a part of the edge on the stepping side of the block-shaped land portion. 3. The step portion according to claim 2, wherein the concave portion provided on the edge on the step side of the block-shaped land portion is provided near a step end of the edge on the step side. Pneumatic tires. 4. The recess provided in the edge on the stepping side of the block-shaped land portion is provided over a length of 30% or more of the entire length of the edge on the stepping side. The pneumatic tire according to claim 2 or 3. 5. The block according to claim 1, wherein the concave portion is provided on at least a part of the edge on the kick-out side of the block-shaped land portion. Pneumatic tire. 6. The concave portion provided on the edge on the kick-out side of the block-shaped land portion is provided near a kick-out end of the edge on the kick-out side. 6. The pneumatic tire according to 5. 7. The recess provided in the edge on the kick-out side of the block-shaped land portion is provided over a length of 30% or more of the entire length of the edge on the kick-out side. The pneumatic tire according to claim 5 or 6, wherein 8. The device according to claim 1, wherein the concave portion is provided on at least a part of the edge of the block-shaped land portion on the tire axial direction side.
The pneumatic tire according to the paragraph. 9. The recess provided in the edge of the block-shaped land portion on the tire axial direction side is provided near a tire axial direction end of the edge on the tire axial direction side. The pneumatic tire according to claim 8, wherein 10. The recess provided on the edge of the block-shaped land portion on the tire axial direction side is provided over a length of 30% or more of the entire length of the edge on the tire axial direction side. 10. The method according to claim 8, wherein:
A pneumatic tire according to claim 1. 11. The air according to claim 1, wherein in the block-shaped land portion, a radially inner portion of the bottom portion in the tire radial direction projects toward a main groove side. Containing tires. 12. The method according to claim 11, wherein an amount of protrusion of the bottom portion in the radial direction inside the tire toward the main groove is not more than 30% of a groove width of the main groove facing the bottom. Pneumatic tires. 13. The method according to claim 1, wherein a depth dimension from the tread surface of the land portion to the bottom portion is 25% or more and 58% or less of a groove depth of the main groove. 1
The pneumatic tire according to the paragraph. 14. The apparatus according to claim 1, wherein when the recess surrounds the periphery of a block end composed of two edges, the angle of the block end is set to an obtuse angle of 90 ° or more. Or the pneumatic tire according to claim 1. 15. The pneumatic tire according to claim 1, wherein the width of the concave portion is 0.5 mm or more and 3 mm or less. 16. The pneumatic tire according to claim 1, wherein the bottom portion is not parallel to the land portion tread. 17. The pneumatic pneumatic pump according to claim 16, wherein the bottom is inclined at an angle θ with respect to a normal line formed on the land tread, and the θ is 45 ° or less. tire. 18. A sipe is formed in the block-shaped land portion.
The pneumatic tire according to any one of claims 1 to 4.