JP2003170704A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of reducing noise by dispersing a load input charged to a block inside the block. <P>SOLUTION: Compression rigidity of the block 18 is changed in the width direction of the tire by changing tilting angles of circumferential wall surfaces 24 and 26. Therefore, when a treading end of the block 18 reaches the ground, the load input charged to the block 18 transmits to the tire at a relatively high speed in a part having high compression rigidity of the block 18. While, in a part having low compression rigidity of the block 18, the load input charged to the block 18 transmits to the tire at a relatively low speed. By providing a difference between the transmitting speeds to the tire of the load input charged to the block 18, the load input applied to the block 18 from the road surface can be dispersed inside the block 18, and the same effect as that in reducing the load input to the tire can be obtained. As a result, the noise can be reduced. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire capable of achieving improvement of tire noise without impairing other performance.

[0002]

2. Description of the Related Art Conventional pneumatic tires have a plurality of circumferential grooves extending substantially in the tire circumferential direction and a plurality of widthwise grooves extending substantially in the tire width direction in a tread pattern for the purpose of considering running in the rain. Is formed, and a land portion called a block is defined by the circumferential groove and the widthwise groove.

However, it is known that pattern noise is generated when the vehicle is running due to the existence of the blocks.

The following techniques are already known as techniques for reducing such pattern noise.

The first is a method of setting a large angle of the lug groove (widthwise groove) with respect to the tire width direction for the purpose of extending the input applied to a single block in the time direction.

Secondly, there is a method in which the length of the block in the circumferential direction is made different and the phase thereof is shifted in the tire to prevent the peak from appearing at a single frequency by using the relationship with other blocks.

These techniques are mainly developed by a two-dimensional idea and have a long history.

However, the effect is not sufficient in automobiles which are required to be quiet in recent years, and
Since it is difficult to design only the noise using the above method in consideration of other performance, new technology is required.

In particular, as shown in FIG. 10, in a single block 200, by increasing the inclination angle θ of the lug groove with respect to the tire width direction (that is, changing the pattern design), the rigidity is lowered and However, it has been pointed out that there is a conflict with uneven wear.

The above-mentioned problem is caused by the fact that the sound is generated by a mixture of the impact sound from the block itself and the sound emission due to the vibration of the tire itself due to the transmission thereof.

Therefore, in consideration of the fact that the input that the block comes into contact with the road surface and floats is transmitted to the tire side, the pattern is made by a method that does not have a peak in the transmission from the block to the tire (belt surface in the tire). The challenge is to propose a technology that can improve noise without changing the basic design.

[0012]

Therefore, in consideration of the above facts, the present invention changes the distribution of the compression rigidity of the block by changing the inclination angle of the wall surface of the block, and the load input applied to the block is changed within the block. An object of the present invention is to provide a pneumatic tire capable of reducing noise by being dispersed by.

[0013]

A pneumatic tire according to claim 1, wherein a plurality of circumferential grooves extending substantially in a tire circumferential direction, a plurality of inclined grooves extending obliquely with respect to the tire circumferential direction, and A pneumatic tire having a plurality of blocks partitioned by a circumferential groove and the inclined groove, wherein a tire has an inclination angle with respect to a tire radial direction of a circumferential wall surface extending along the circumferential groove of the block. It is characterized in that the compression rigidity of the block is changed in the tire width direction from one of the step-in edge and the kick-out edge of the block to the other in the circumferential direction.

Next, the function and effect of the pneumatic tire according to claim 1 will be described.

In the pneumatic tire of the present invention, the inclination angle of the wall surface in the circumferential direction of the block with respect to the tire radial direction is changed over the tire circumferential direction, so that one of the stepping edge or the kicking edge of the block extends to the other. The compression rigidity of the block is changed in the tire width direction.

That is, for example, on the stepped end side of the block, the circumferential wall surface on the outer side in the tire width direction is provided with an inclination angle so that the circumferential wall surface inclines outward from the block surface toward the root. Is formed in. At this time, the circumferential wall surface on the kick-out side of the block on the outer side in the tire width direction is substantially vertical (substantially parallel to the tire radial direction).

On the other hand, on the kick-out end side of the block, the circumferential wall surface on the inner side in the tire width direction has an inclination angle so that the circumferential wall surface inclines inward in the tire width direction from the surface of the block toward the root. Has been formed. At this time, the circumferential wall surface on the tire width direction outer side on the stepped end side of the block is substantially vertical (generally parallel to the tire radial direction).

As described above, by providing the circumferential wall with a change in the inclination angle, the compression rigidity is high on the outside of the tire width direction on the stepped end side of the block, and the compression rigidity increases as it moves toward the inside of the tire width direction. It's getting low. Further, on the kick-out end side of the block, the compression rigidity is high inside the tire width direction and decreases as it moves outward in the tire width direction.

When the tire rotates and the block comes into contact with the ground, the block receives a load input from the road surface. However, when the stepped end of the block comes into contact with the ground, the block has a high compressive rigidity in the block. The applied load input is transmitted to the tire (belt surface in the tire) at a relatively high speed. On the other hand, in the low compression rigidity part of the block,
The load input acting on the block is transmitted to the tire (belt surface in the tire) at a relatively low speed.

As described above, by providing a difference in the transmission speed of the load input acting on the block to the tire (belt surface inside the tire), the load input applied to the block from the road surface can be dispersed within the block. It is possible to obtain the same effect as that when the load input to the tire is reduced. As a result, so-called noise (pattern noise) can be reduced.

The above-described actions and effects are also the same when the kick-out end side of the block is in contact with the road surface.

In the present specification, the "tilted groove" means
It also includes a widthwise groove extending in the tire width direction at an angle of approximately 90 degrees with respect to the tire circumferential direction.

In the pneumatic tire according to claim 2, a plurality of circumferential grooves extending substantially in the tire circumferential direction, a plurality of inclined grooves extending obliquely with respect to the tire circumferential direction, the circumferential groove and the inclination. A plurality of blocks partitioned by grooves, wherein the inclination angle of the inclination direction wall surface of the block extending along the inclined groove with respect to the tire radial direction is changed over the tire width direction. The compression rigidity of the block is varied in the tire width direction from one of the tire width direction outer edge or the tire width direction inner edge of the block to the other.

Next, the function and effect of the pneumatic tire of claim 2 will be described.

In the pneumatic tire of the present invention, the tire width direction outer edge or the tire width direction inner edge of the block is changed by changing the inclination angle of the block inclination direction wall surface with respect to the tire radial direction in the tire width direction. The compression rigidity of the block is changed in the tire width direction from one side to the other side.

That is, for example, the inclination direction wall surface on the stepping end side of the block is formed to have an inclination angle, and the outer portion in the tire width direction of the inclination direction wall surface is formed to incline toward the stepping side from the surface of the block toward the root. Has been done. At this time, the tire width direction inner side portion of the inclined wall surface on the stepping edge side of the block is substantially vertical (generally parallel to the tire radial direction).

On the other hand, the inclination direction wall surface on the kicking edge side of the block is provided with an inclination angle so that the inner portion in the tire width direction of the inclination direction wall surface is inclined from the surface of the block toward the kicking side. Has been done. At this time, the tire width direction outer side portion of the inclined wall surface on the kicking edge side of the block is substantially vertical (generally parallel to the tire radial direction).

As described above, by changing the inclination angle on the wall surface in the inclination direction, on the stepped end side of the block, the compression rigidity is high at the outer portion in the tire width direction and moves to the inner portion in the tire width direction. As a result, the compression rigidity is low. Further, on the kick-out end side of the block, the compression rigidity is high at the inner portion in the tire width direction and becomes lower as it moves to the outer portion in the tire width direction.

When the tire rotates and the block comes into contact with the ground, the block receives a load input from the road surface. However, when the stepped end of the block comes into contact with the ground, the block has a high compressive rigidity at the block. The applied load input is transmitted to the tire (belt surface in the tire) at a relatively high speed. On the other hand, in the low compression rigidity part of the block,
The load input acting on the block is transmitted to the tire (belt surface in the tire) at a relatively low speed.

As described above, by providing a difference in the transmission speed of the load input acting on the block to the tire (belt surface inside the tire), the load input applied to the block from the road surface can be dispersed within the block. It is possible to obtain the same effect as that when the load input to the tire is reduced. As a result, so-called noise (pattern noise) can be reduced.

The above-described actions and effects are also the same when the kick-out end side of the block is in contact with the road surface.

In the present specification, "inclination wall surface"
Also includes a width direction wall surface extending along a width direction groove extending in the tire width direction.

In the pneumatic tire according to claim 3, a plurality of circumferential grooves extending substantially in the tire circumferential direction, a plurality of inclined grooves extending obliquely with respect to the tire circumferential direction, the circumferential groove and the inclination are provided. A plurality of blocks partitioned by grooves, wherein the inclination angle of the circumferential wall surface extending along the circumferential groove of the block with respect to the tire radial direction is changed over the tire circumferential direction. Then, the compression rigidity of the block is changed in the tire width direction from one of the stepping edge or the kicking edge of the block to the other,
The inclination angle with respect to the tire radial direction of the inclined wall surface extending along the inclined groove of the block is changed over the tire width direction, and one of the tire width direction outer end edge or the tire width direction inner end edge of the block is changed. The compression rigidity of the block is changed in the tire width direction toward the other side.

Next, the function and effect of the pneumatic tire of claim 3 will be described.

According to the pneumatic tire of the present invention, as described in claims 1 and 2, the noise can be further effectively reduced by the synergistic effect.

In the pneumatic tire according to claim 4, the variation of the inclination angle of the circumferential wall surface of the block with respect to the tire radial direction is monotonically increased or decreased along the tire circumferential direction. To do.

Next, the function and effect of the pneumatic tire of claim 4 will be described.

The variation in the inclination angle of the circumferential wall surface of the block with respect to the tire radial direction preferably monotonically increases or decreases along the tire circumferential direction. This makes it possible to reduce noise more reliably.

The term "monotonically increasing or decreasing" refers to the case where the increase or decrease is changing in one direction, and the change in the tilt angle is not always differentiable. That is,
Even if there is a non-differentiable corner, it may increase or decrease monotonically instead of a smooth change.

According to a fifth aspect of the present invention, the variation of the inclination angle of the wall surface in the inclination direction of the block with respect to the tire radial direction monotonically increases or decreases along the tire width direction. To do.

Next, the function and effect of the pneumatic tire according to claim 5 will be described.

It is preferable that the variation of the inclination angle of the wall surface in the inclination direction of the block with respect to the tire radial direction monotonically increases or decreases along the tire width direction. This makes it possible to reduce noise more reliably.

In the pneumatic tire according to claim 6, the variation of the inclination angle of the circumferential wall surface of the block with respect to the tire radial direction monotonically increases or decreases along the tire circumferential direction. The variation of the inclination angle of the wall surface in the inclination direction with respect to the tire radial direction is characterized by monotonically increasing or decreasing along the tire width direction.

Next, the function and effect of the pneumatic tire according to claim 6 will be described.

The variation of the inclination angle of the circumferential wall surface of the block with respect to the tire radial direction monotonically increases or decreases along the tire circumferential direction, and the variation of the inclination angle of the inclination wall surface of the block with respect to the tire radial direction is: It is preferably monotonically increasing or decreasing along the tire width direction. Thereby, the noise can be further reduced by the synergistic effect.

In the pneumatic tire according to claim 7, the circumferential wall surface of the block is formed such that the variation of the inclination angle of the circumferential wall surface with respect to the tire radial direction has only a minimum value or a maximum value. It is characterized by being.

Next, the function and effect of the pneumatic tire according to claim 7 will be described.

The inventors further conducted experiments on the relationship between the variation of the inclination angle of the circumferential wall surface of the block with respect to the tire radial direction and the compression rigidity of the block.

As a result, even if the variation of the inclination angle of the circumferential wall surface of the block with respect to the tire radial direction does not monotonically increase or decrease along the tire circumferential direction, the circumferential wall surface of the block is changed to the tire diameter of the circumferential wall surface. It was found that the compression rigidity distribution of the block can be changed along the tire width direction and the noise can be reduced by forming the variation of the inclination angle with respect to the direction so as to have only a minimum value or a maximum value.

Therefore, as in the present invention, noise is generated by forming the circumferential wall surface of the block so that the variation of the inclination angle of the circumferential wall surface with respect to the tire radial direction has only a minimum value or a maximum value. It can be reduced.

In the pneumatic tire according to claim 8, the inclined wall surface of the block is formed such that the variation of the inclination angle of the inclined wall surface with respect to the tire radial direction has only a minimum value or a maximum value. It is characterized by being.

Next, the function and effect of the pneumatic tire of claim 8 will be described.

According to the experiments by the inventors, even if the variation of the inclination angle of the wall surface in the inclination direction of the block with respect to the tire radial direction does not monotonically increase or decrease along the tire width direction,
The distribution of compression rigidity of the block is changed along the tire width direction by forming the inclination wall surface of the block so that the inclination angle of the inclination wall surface with respect to the tire radial direction has only one minimum value or maximum value. It was found that the noise can be reduced.

Therefore, as in the present invention, noise is generated by forming the inclined wall surface of the block so that the variation of the inclination angle of the inclined wall surface with respect to the tire radial direction has only a minimum value or a maximum value. It can be reduced.

In the pneumatic tire according to claim 9, the circumferential wall surface of the block is formed so that the variation of the inclination angle of the circumferential wall surface with respect to the tire radial direction has only one minimum value or the maximum value. The inclination-direction wall surface of the block is formed so that a variation in the inclination angle of the inclination-direction wall surface with respect to the tire radial direction has only a minimum value or a maximum value.

Next, the function and effect of the pneumatic tire according to claim 9 will be described.

According to the present invention, similar to the actions and effects described in claims 7 and 8, noise can be further reduced by the synergistic effect.

According to the pneumatic tire of claim 10,
The inclination angle of the circumferential wall surface of the block with respect to the tire radial direction or the inclination angle of the inclination wall surface of the block with respect to the tire radial direction is smoothly changed.

Next, the function and effect of the pneumatic tire according to claim 10 will be described.

It is preferable that the inclination angle of the circumferential wall of the block with respect to the tire radial direction or the inclination angle of the inclined wall of the block with respect to the tire radial direction is smoothly changed.

The phrase "the inclination angle changes smoothly" means that the inclination angle change is a function that can be differentiated at least once.

According to the pneumatic tire of claim 11,
A difference between a portion of the circumferential wall surface of the block having a large inclination angle with respect to the tire radial direction and a portion of the block having a small inclination angle is not less than 10 degrees and not more than 30 degrees, and the inclination angle of the inclination wall surface of the block with respect to the tire radial direction is large. The difference between the portion and the small portion is characterized by being 10 degrees or more and 30 degrees or less.

Next, the function and effect of the pneumatic tire according to claim 11 will be described.

The inventors repeated experiments on the relationship between the change in the inclination angle of the circumferential wall surface of the block with respect to the tire radial direction and the change in the inclination angle of the inclination direction wall surface with respect to the tire radial direction and noise.

As a result, it was found that the noise can be reduced when the change of the inclination angle of the circumferential wall surface of the block with respect to the tire radial direction and the change of the inclination angle of the inclined wall surface with respect to the tire radial direction are 10 degrees or more and 30 degrees or less. .

Therefore, the difference between the portion of the wall surface in the circumferential direction of the block having a large inclination angle with respect to the tire radial direction and the portion having a small inclination angle thereof is set to 10 degrees or more and 30 degrees or less, and the portion of the wall surface in the inclination direction of the block having a large inclination angle with respect to the tire radial direction is set. By setting the difference between the small part and the small part from 10 degrees to 30 degrees,
Noise can be reduced.

[0067]

BEST MODE FOR CARRYING OUT THE INVENTION [First Embodiment] A pneumatic tire according to a first embodiment of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the pneumatic tire 10
In the tread 12 (appropriately abbreviated as “tire 10”), a plurality of circumferential grooves 14 extending along the tire circumferential direction (arrow A direction and arrow B direction) and these circumferential grooves 14 intersect, A plurality of rectangular blocks 18 are partitioned by the plurality of lug grooves 16 (width direction grooves) extending along the tire width direction (arrow C direction or arrow D direction).

The pneumatic tire 10 rotates in the direction of arrow A when the vehicle moves forward. Therefore, the edge of the block 18 on the arrow A direction side becomes the stepping edge,
The edge on the arrow B direction side is the kicked edge. The edge of the block 18 on the arrow C direction side is the outer edge in the tire width direction, and the edge on the arrow D direction side is the inner edge in the tire width direction.

Here, the shape of the block 18, which is a feature of the pneumatic tire 10 of the present invention, will be described in detail.

As shown in FIGS. 2 and 3 (C), the widthwise wall surface 20 of the block 18 on the stepping edge side (arrow A direction in FIG. 2) has a predetermined inclination angle θ with respect to the tire radial direction.
It is inclined at 1. Therefore, the width direction wall surface 20 is inclined toward the stepping side of the block 18 as it is located at the root from the surface of the block 18.

The widthwise wall surface 20 is inclined at a constant inclination angle θ1 in the tire width direction.

On the other hand, the widthwise wall surface 22 of the block 18 on the kicking edge side (the direction of the arrow B in FIG. 2) is inclined at a predetermined inclination angle θ2 with respect to the tire radial direction. Therefore, from the surface of the block 18 to the root,
The width direction wall surface 22 is inclined toward the kicking side of the block 18.

The widthwise wall surface 22 is inclined at a constant inclination angle θ2 in the tire width direction.

Further, as shown in FIGS. 2 and 3B,
The tire width direction outer edge side of the block 18 (arrow C in FIG. 2)
(Direction side) the circumferential wall surface 24 and the block 18
At the stepped edge side (the direction of arrow A in FIG. 2) of,
The block 18 is formed to incline outward from the surface of the block 18 toward the root in the tire width direction.

Further, as shown in FIG. 2 and FIG.
The kicking edge side of the block 18 of the circumferential wall surface 24 (see FIG. 2).
In the portion on the middle arrow B direction side), it is formed substantially perpendicular to the surface of the block 18 (not inclined with respect to the tire radial direction).

As described above, the circumferential wall surface 24 on the tire width direction outer end edge side (arrow C direction side in FIG. 2) of the block 18 is formed.
Is formed such that the inclination angle θ3 thereof gradually increases from the kicking edge side (the arrow B direction side in FIG. 2) of the block 18 toward the stepping edge side (the arrow A direction side in FIG. 2). It should be noted that this inclination angle θ3 is preferably monotonically increasing.

The inclination angle θ3 of the circumferential wall surface 24 is
It is preferable that the change smoothly occurs in the tire circumferential direction.

Furthermore, it is preferable that the difference between the portion of the circumferential wall surface 24 where the inclination angle θ3 is large and the portion where the inclination angle θ3 is small is set in the range of 10 degrees to 30 degrees.

On the other hand, as shown in FIGS. 2 and 3A,
The tire width direction inner edge side of the block 18 (arrow D in FIG. 2)
(Direction side) the circumferential wall surface 26 and the block 18
In the part of the kicking edge side (the direction of arrow B in FIG. 2) of,
The block 18 is formed to incline inward in the tire width direction from the surface of the block 18 toward the root.

Further, as shown in FIGS. 2 and 3B,
A portion of the circumferential wall surface 26 on the stepping edge side of the block 18 (on the side of the arrow A in FIG. 2) is formed substantially perpendicular to the surface of the block 18 (not inclined with respect to the tire radial direction). .

As described above, the circumferential wall surface 26 of the block 18 on the inner edge side in the tire width direction (on the side of the arrow D in FIG. 2).
Is formed so that the inclination angle θ4 thereof gradually increases from the stepped edge side (the arrow A direction in FIG. 2) of the block 18 to the kicked edge side (the arrow B direction in FIG. 2). In addition, it is preferable that the inclination angle θ4 is monotonically increasing.

The inclination angle θ4 of the circumferential wall surface 26 is
It is preferable that the change smoothly occurs in the tire circumferential direction.

Further, it is preferable that the difference between the portion of the circumferential wall surface 26 where the inclination angle θ4 is large and the portion where the inclination angle θ4 is small is set in the range of 10 degrees to 30 degrees.

By inclining the circumferential wall surfaces 24 and 26 as described above, at the stepped end side (the arrow A direction in FIG. 2) of the block 18, the tire width direction outer side (the arrow C direction in FIG. 2 side). 2), the compression rigidity is high, and the compression rigidity becomes lower as it moves to the inside of the tire width direction (the direction of the arrow D in FIG. 2). Further, at the kick-out end side (the arrow B direction side in FIG. 2) of the block 18, the compression rigidity is high at the tire width direction inner side (the arrow D direction side in FIG. 2) and the tire width direction outer side (FIG. 2). The compression rigidity becomes lower as it moves to the portion indicated by the middle arrow C direction). That is, the compression rigidity of the block 18 changes along the tire width direction.

Next, the operation and effect of the pneumatic tire 10 of this embodiment will be described.

In a conventional pneumatic tire block, the inclination angle of each wall surface of the block with respect to the tire radial direction is constant, and the compression rigidity of each edge of the block is substantially equal.

However, when a block having the same compressive rigidity at each edge touches the road surface, the distribution of the load input applied to the block from the road surface is concentrated in the local area inside the block depending on the rolling of the tire. (Belt surface inside the tire)
There is a peak in the vibration transmission to.

That is, for example, the load inputs acting on all parts of the stepped edge of the block are transmitted to the tire (belt surface in the tire) at substantially equal speeds. As a result, the vibration transmission of the load input to the tire reaches a peak and a large noise is generated. This means that even if the load input acts on all parts of the kicked edge of the block,
It is the same.

Therefore, the pneumatic tire 10 of this embodiment is used.
As described above, the compression rigidity of the block 18 is changed along the tire width direction by changing the inclination angle of the circumferential wall surfaces 24 and 26. Therefore, when the stepped end of the block 18 touches the ground, In the portion of the block 18 having high compression rigidity, the load input acting on the block 18 is transmitted to the tire (belt surface in the tire) at a relatively high speed.
On the other hand, in the portion of the block 18 having low compression rigidity, the load input acting on the block 18 is transmitted to the tire (the belt surface in the tire) at a relatively low speed.

As described above, by providing a difference in the transmission speed of the load input acting on the block 18 to the tire (belt surface in the tire), the load input applied to the block 18 from the road surface is dispersed in the block 18. Therefore, it is possible to obtain the same effect as that when the load input to the tire is reduced. As a result, so-called noise (pattern noise) can be reduced.

[Second Embodiment] Next, a pneumatic tire according to a second embodiment of the present invention will be described.

Incidentally, the pneumatic tire 10 of the first embodiment.
The same components as those in FIG.

As shown in FIG. 4, the tire width direction outer edge side of the block 30 of the pneumatic tire of this embodiment (see FIG. 4).
The circumferential wall surface 32 on the side of the middle arrow C) is inclined at a predetermined inclination angle with respect to the tire radial direction. Therefore, as it is located at the root from the surface of the block 30,
The circumferential wall surface 32 is inclined toward the tire width direction outer side of the block 30 (the arrow C direction side in FIG. 4).

The circumferential wall surface 32 is inclined at a constant inclination angle in the tire circumferential direction.

On the other hand, the circumferential wall surface 34 on the tire width direction inner edge side (arrow D direction side in FIG. 4) of the block 30 is inclined at a predetermined inclination angle with respect to the tire radial direction. Therefore, as it is located at the root from the surface of the block 30, the circumferential wall surface 34 inclines toward the tire width direction inner side of the block 30 (arrow D direction side in FIG. 4).

The circumferential wall surface 34 is inclined at a constant inclination angle over the tire circumferential direction.

Further, as shown in FIG. 4, the width direction wall surface 3 of the stepped end edge side of the block 30 (the arrow A direction side in FIG. 4).
6, and the portion on the tire width direction outer edge side (the arrow C direction in FIG. 4) of the block 30 faces the stepping side (the arrow A direction in FIG. 4) from the surface of the block 30 toward the root. Is formed so as to be inclined.

Further, at the portion of the width direction wall surface 36 on the tire width direction inner end side (direction of arrow D in FIG. 4), the block 3
It is formed substantially perpendicular to the surface of 0 (not inclined with respect to the tire radial direction).

As described above, the inclination angle of the width direction wall surface 36 of the block 30 on the stepping edge side (arrow A direction in FIG. 4) is on the tire width direction inner edge side (arrow D direction in FIG. 4). From the part to the outer edge side in the tire width direction (arrow C in FIG. 4)
It is formed so as to gradually increase toward the (direction side) portion. In addition, it is preferable that the inclination angle is monotonically increasing.

Further, it is preferable that the inclination angle of the width direction wall surface 36 is smoothly changed in the tire width direction.

Further, it is preferable that the difference between the portion having a large inclination angle and the portion having a small inclination angle of the width direction wall surface 36 is set in the range of 10 degrees to 30 degrees.

On the other hand, as shown in FIG. 4, the width direction wall surface 3 of the kicking edge of the block 30 (on the side of the arrow B in FIG. 4).
8, and at the portion on the inner edge side in the tire width direction (the direction of the arrow D in FIG. 4), from the surface of the block 30 toward the root, toward the kicking side of the block 30 (the direction of the arrow B in FIG. 4). It is formed to be inclined.

Further, the portion of the width direction wall surface 38 on the outer side in the tire width direction (direction of arrow C in FIG. 4) is formed substantially perpendicular to the surface of the block 30 (not inclined with respect to the tire radial direction). Has been done.

As described above, the width direction wall surface 38 of the block 30 on the kicking edge side (the arrow B direction side in FIG. 4) has the inclination angle outside the tire width direction (the arrow C direction side in FIG. 4). Is formed so as to gradually increase from the inner side in the tire width direction (on the side of the arrow D in FIG. 4).
In addition, it is preferable that the inclination angle is monotonically increasing.

Further, it is preferable that the inclination angle of the width direction wall surface 38 smoothly changes in the tire width direction.

Further, it is preferable that the difference between the portion having a large inclination angle and the portion having a small inclination angle of the width direction wall surface 38 is set in the range of 10 degrees to 30 degrees.

As described above, the width direction wall surfaces 36 and 38 are changed in the inclination angle, so that the stepping end side of the block 30 (direction of arrow A in FIG. 4) is outside of the tire width direction (in FIG. 4). The compression rigidity is high in the part of the arrow C direction side),
The compression rigidity becomes lower as it moves to the inner side in the tire width direction (the direction of the arrow D in FIG. 4). Further, on the kick-out end side (the arrow B direction side in FIG. 4) of the block 30, the compression rigidity is high at the inner side in the tire width direction (the arrow D direction side in FIG. 4) and the tire width direction outer side (arrow in FIG. 4). The compression rigidity decreases as it moves to the (C direction side) portion. That is, the compressive rigidity of the block 30 changes along the tire width direction.

Next, the operation and effect of the pneumatic tire of this embodiment will be described.

According to the pneumatic tire of this embodiment, like the pneumatic tire 10 of the first embodiment, when the tire rotates and the block 30 touches the ground, the block 30 receives a load input from the road surface. When the stepped end of the block 30 comes into contact with the ground, the load input acting on the block 30 is transmitted to the tire (the belt surface in the tire) at a relatively high speed in the portion of the block 30 having high compression rigidity.
On the other hand, in the portion of the block 30 having low compression rigidity, the load input acting on the block 30 is transmitted to the tire (the belt surface in the tire) at a relatively low speed.

Therefore, by providing a difference in the transmission speed of the load input acting on the block 30 to the tire (belt surface in the tire), the load input applied to the block 30 from the road surface can be dispersed in the block 30. Therefore, it is possible to obtain the same effect as that when the load input to the tire is reduced. As a result, so-called noise (pattern noise) can be reduced.

[Third Embodiment] Next, a pneumatic tire according to a third embodiment of the present invention will be described.

The same components as those of the pneumatic tires of the first and second embodiments are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

The block of the pneumatic tire according to this embodiment has the features of the block 18 of the pneumatic tire 10 according to the first embodiment and the features of the block 30 of the pneumatic tire according to the second embodiment. Is.

That is, as shown in FIG. 5, in the pneumatic tire of this embodiment, the block 50 is the circumferential wall surface 52 on the tire width direction outer end edge side (the arrow C direction side in FIG. 5), and A portion of the step 50 on the stepping edge side (arrow A direction side in FIG. 5) is formed so as to incline toward the root from the surface of the block 50 toward the tire width direction outer side (arrow C direction side in FIG. 5).

In the portion of the circumferential wall surface 52 on the side of the protruding edge of the block 50 (the direction of the arrow B in FIG. 5), it is substantially perpendicular to the surface of the block 50 (not inclined with respect to the tire radial direction). ) Is formed.

As described above, the circumferential wall surface 52 on the tire width direction outer end edge side (arrow C direction side in FIG. 5) of the block 50.
Is formed such that the inclination angle thereof gradually increases from the kicking edge side (the arrow B direction side in FIG. 5) portion of the block 50 toward the stepping edge side (the arrow A direction side in FIG. 5) portion. ing. In addition, it is preferable that the inclination angle is monotonically increasing.

On the other hand, as shown in FIG. 5, the block 50 has a circumferential wall surface 54 on the tire width direction inner edge side (arrow D direction side in FIG. 5) and the kick edge side (FIG. 5). In the portion of the middle arrow B direction), the tire width direction inner side from the surface of the block 50 toward the root (arrow D in FIG. 5).
It is formed so as to incline toward the (direction side).

Further, in the portion of the circumferential wall surface 54 on the stepped edge side of the block 50 (direction of arrow A in FIG. 5), it is substantially perpendicular to the surface of the block 50 (not inclined with respect to the tire radial direction). Is formed in.

As described above, the circumferential wall surface 54 on the tire width direction inner edge side (the arrow D direction side in FIG. 5) of the block 50.
Is formed such that its inclination angle gradually increases from the stepped edge side (the arrow A direction side in FIG. 5) of the block 50 toward the kicked edge side (the arrow B direction side in FIG. 5). ing. In addition, it is preferable that the inclination angle is monotonically increasing.

Further, as shown in FIG. 5, the width direction wall surface 5 on the stepped edge side of the block 50 (the arrow A direction side in FIG. 5).
6, and the portion of the block 50 on the tire width direction outer edge side (the arrow C direction side in FIG. 5) is formed so as to incline from the surface of the block 50 toward the root toward the stepping side. .

Further, at the portion on the tire width direction inner end side of the width direction wall surface 56 (the direction of the arrow D in FIG. 5), the block 5 is
It is formed substantially perpendicular to the surface of 0 (not inclined with respect to the tire radial direction).

As described above, the width direction wall surface 56 of the block 50 on the stepping edge side (the arrow A direction in FIG. 5) has the inclination angle on the tire width direction inner edge side (the arrow D direction in FIG. 5). From the part to the outer edge side in the tire width direction (arrow C in FIG. 5)
It is formed so as to gradually increase toward the (direction side) portion. In addition, it is preferable that the inclination angle is monotonically increasing.

On the other hand, as shown in FIG. 5, the widthwise wall surface 5 of the kicking edge of the block 50 (the direction of the arrow B in FIG. 5).
8 and the portion on the inner edge side in the tire width direction (the direction of the arrow D in FIG. 5) is formed so as to incline toward the root of the block 50 from the surface of the block 50 toward the root.

Further, at the portion on the tire width direction outer end side of the width direction wall surface 58 (direction of arrow C in FIG. 5), the block 5 is
It is formed substantially perpendicular to the surface of 0 (not inclined with respect to the tire radial direction).

As described above, the width direction wall surface 58 on the kicking edge side (the arrow B direction side in FIG. 5) of the block 50 has the inclination angle outside the tire width direction (the arrow C direction side in FIG. 5). Is formed so as to gradually increase from the inside toward the tire width direction inner side (the direction of the arrow D in FIG. 5).
In addition, it is preferable that the inclination angle is monotonically increasing.

As described above, at the stepped-in end side (the arrow A direction in FIG. 5) of the block 50, the compression rigidity is high at the outer side in the tire width direction (the arrow C direction in FIG. 5).
The compression rigidity becomes lower as it moves to the inner side in the tire width direction (the direction of the arrow D in FIG. 5). Further, at the kick-out end side (the arrow B direction side in FIG. 5) of the block 50, the compression rigidity is high at the tire width direction inner side (the arrow D direction side in FIG. 5) and the tire width direction outer side (FIG. 5). The compression rigidity becomes lower as it moves to the portion indicated by the middle arrow C direction).

Therefore, due to the synergistic effect, the change in the compression rigidity of the block 50 along the tire width direction is
This is much larger than the change in the compression rigidity of the blocks 18 and 30 of the pneumatic tires of the embodiment and the second embodiment.

Next, the function and effect of the pneumatic tire of this embodiment will be described.

According to the pneumatic tire of the present invention, the compressive rigidity changes along the tire width direction of the block 50 due to the synergistic effect for the same reason as the operation described in the first and second embodiments. Can be larger.

Therefore, the difference in the transmission speed of the load input acting on the block 50 to the tire (belt surface in the tire) can be further increased, and the load input applied to the block 50 from the road surface can be further improved in the block 50. It can be dispersed effectively. As a result, it is possible to obtain the same effect as that when the load input to the tire is greatly reduced, and it is possible to significantly reduce noise (pattern noise).

[Fourth Embodiment] Next, a pneumatic tire according to a fourth embodiment of the present invention will be described.

[0133] The pneumatic tire 10 of the first embodiment.
The same components as those in FIG.

As shown in FIG. 6, in the pneumatic tire of this embodiment, the widthwise wall surface 72 of the block 70 on the stepping edge side (the arrow A side in FIG. 6) is inclined at a predetermined angle with respect to the tire radial direction. Inclined at an angle. Therefore, the widthwise wall surface 72 is inclined toward the step-in side of the block 70 as it is located at the root from the surface of the block 70. The width-direction wall surface 72 is inclined at a constant inclination angle in the tire width direction.

On the other hand, the widthwise wall surface 74 of the block 70 on the kicking edge side (arrow B side in FIG. 6) is inclined at a predetermined inclination angle with respect to the tire radial direction. Therefore,
The widthwise wall surface 74 is inclined toward the kicking side of the block 70 as it is located at the root from the surface of the block 70. The widthwise wall surface 74 is inclined at a constant inclination angle over the tire width direction.

Further, the circumferential wall surface 76 of the block 70 on the outer edge side in the tire width direction (the direction of the arrow C in FIG. 6) has the only minimum value in which the inclination angle of the circumferential wall surface 76 with respect to the tire radial direction varies. So that it is formed.

That is, at the stepped edge side (the arrow A direction in FIG. 6) and the kicked edge side (the arrow B direction in FIG. 6) of the circumferential wall surface 76, the surface of the block 70 faces the root. And is formed so as to incline outward in the tire width direction (direction of arrow C in FIG. 6).

The tire circumferential center portion 76M of the circumferential wall surface 76 is formed substantially perpendicular to the surface of the block 70 (not inclined with respect to the tire radial direction). The portion 76M has the minimum value of the angle fluctuation. The position of the minimum value can be calculated by partially differentiating the equation representing the angular fluctuation of the circumferential wall surface 76, and the minimum value can be calculated by substituting the calculation result into the equation.

As described above, the circumferential wall surface 76 on the tire width direction outer end edge side (the arrow C direction side in FIG. 6) of the block 70.
Is the block 70 whose inclination angle with respect to the tire radial direction is
Of the tire circumferential direction central portion 76M from the stepping edge side (see FIG. 6).
It is formed so as to gradually increase toward the middle arrow A direction side and the kicking edge side (the arrow B direction side in FIG. 6). The inclination angle changes smoothly.

On the other hand, the circumferential wall surface 78 of the block 70 on the inner edge side in the tire width direction (on the side of the arrow D in FIG. 6) has the only maximum value in the variation of the inclination angle of the circumferential wall surface 78 with respect to the tire radial direction. So that it is formed.

That is, it is located in the tire circumferential direction central portion 78M from the stepping edge side (the arrow A side in FIG. 6) and the kicking edge side (the arrow B direction in FIG. 6) of the circumferential wall surface 78. Therefore, the block 70 is formed so as to gradually incline toward the root from the surface of the block 70 toward the inner side in the tire width direction (direction of arrow D in FIG. 6). The inclination angle is greatest in the tire circumferential direction central portion 78M, and the tire circumferential direction central portion 78M has the maximum value of the angular fluctuation.
The position of the maximum value can be calculated by partially differentiating the equation representing the angular fluctuation of the circumferential wall surface 78, and the maximum value can be calculated by substituting the calculation result into the equation.

As described above, the circumferential wall surface 78 of the block 70 on the outer edge side in the tire width direction (on the side of arrow C in FIG. 6).
The inclination angle of the block 70 is the step edge side (the arrow A direction in FIG. 6) and the kick edge side (the arrow B in FIG. 6) of the block 70.
Direction side) toward the tire circumferential direction central portion 78M. The inclination angle changes smoothly.

Therefore, in the pneumatic tire block 70 of the present embodiment, the tire width direction outer side (arrow C in FIG. 6).
Direction side) portion, and the tire circumferential center portion 76
M has the lowest compression rigidity, is the inner portion in the tire width direction (the direction of the arrow D in FIG. 6), and has the highest compression rigidity in the tire circumferential center portion 78M.

Next, the function and effect of the pneumatic tire of this embodiment will be described.

The inventors have found that the circumferential wall surface 7 of the block 70 is
Further experiments were conducted on the relationship between the variation of the inclination angle of Nos. 6 and 78 with respect to the tire radial direction and the compression rigidity of the block 70.

As a result, the circumferential wall surface 7 of the block 70 is
Even if the variation of the inclination angle of 6, 78 with respect to the tire radial direction does not monotonically increase or decrease along the tire circumferential direction,
The circumferential wall surfaces 76 and 78 of the block 70 are
By forming so that the variation of the inclination angle with respect to the tire radial direction of 6, 78 has only a minimum value or a maximum value,
It was found that the distribution of the compression rigidity of the block 70 can be changed along the tire width direction, and the noise can be reduced.

Therefore, as in this embodiment, the block 7
No. 0 tire width direction outer edge side (arrow C direction in FIG. 6) circumferential wall surface 76 is formed so that the variation of the inclination angle of the circumferential wall surface 76 with respect to the tire radial direction has only one minimum value.
Further, the circumferential wall surface 78 of the block 70 on the inner edge side in the tire width direction (the arrow D direction side in FIG. 6) is formed so that the variation of the inclination angle of the circumferential wall surface 78 with respect to the tire radial direction has only one maximum value. Accordingly, a difference can be provided between the transmission speed of the load input to the tire at the tire width direction outer side portion of the block 70 and the transmission speed of the load input at the tire width direction inner side portion to the tire. ) Can be reduced.

[Fifth Embodiment] Next, a pneumatic tire according to a fifth embodiment of the present invention will be described.

Incidentally, the pneumatic tire 10 of the first embodiment.
The same components as those in FIG.

As shown in FIG. 7, in the pneumatic tire of this embodiment, the circumferential wall surface 92 on the tire width direction outer edge side (the arrow C direction side in FIG. 7) of the block 90 is in the tire radial direction. It is inclined at a predetermined inclination angle. Therefore, as it is located from the surface of the block 90 to the root,
The circumferential wall surface 92 is inclined outward in the tire width direction (direction of arrow C in FIG. 7). The circumferential wall surface 92 is
The tire is inclined at a constant inclination angle in the tire circumferential direction.

On the other hand, the circumferential wall surface 94 on the tire width direction inner edge side (the arrow D direction side in FIG. 7) of the block 90 is inclined at a predetermined inclination angle with respect to the tire radial direction. Therefore, the circumferential wall surface 94 is inclined inward in the tire width direction (on the side of the arrow D in FIG. 7) as it is located at the root from the surface of the block 90. In addition, this circumferential wall surface 94
Are inclined at a constant inclination angle over the tire circumferential direction.

Further, the width direction wall surface 96 on the kicking edge side (the direction of the arrow B in FIG. 7) of the block 90 is the width direction wall surface 9
It is formed so that the variation of the inclination angle of No. 6 with respect to the tire radial direction has only one minimum value.

That is, in the portion on the outer side in the tire width direction (on the side of arrow C in FIG. 7) and the portion on the inner side in the tire width direction (on the side of arrow D in FIG. 7) of the width direction wall surface 96, the surface of the block 90 is basically The block 90 is formed so as to incline toward the kick-out side (the direction of arrow B in FIG. 7).

The tire width direction central portion 96M of the width direction wall surface 96 is formed substantially perpendicular to the surface of the block 90 (not inclined with respect to the tire radial direction), and this portion changes in angle. Is the minimum value of. In addition,
The position of the minimum value can be calculated by partially differentiating an equation representing the angular fluctuation of the widthwise wall surface 96, and the minimum value can be calculated by substituting the calculation result into the above equation. However, in the case of a non-differentiable change, the only extreme value is the minimum value or the maximum value that is limited to one point other than the end on that side.

As described above, the width direction wall surface 96 of the block 90 on the kicking edge side (the direction of arrow B in FIG. 7) has an inclination angle with respect to the tire radial direction from the tire width direction central portion 96M of the block 90 to the tire. It is formed so as to gradually increase toward the width direction outer side (arrow C direction side in FIG. 7) and the tire width direction inner side (arrow D direction side in FIG. 7). This inclination angle is 96M in the tire width direction central portion.
Is monotonically increasing when viewed as a reference, and monotonically decreases when viewed at the tire width direction outer end and the tire width direction inner end.

On the other hand, the width direction wall surface 98 on the stepping edge side of the block 90 (the direction of the arrow A in FIG. 7) is the width direction wall surface 9
No. 8 is formed so that the variation of the inclination angle with respect to the tire radial direction has only one maximum value.

That is, the tire width direction central portion 98M is located from the tire width direction outer side (arrow C direction side in FIG. 7) and the tire width direction inner side (arrow D direction side in FIG. 7) portions of the width direction wall surface 98. Therefore, the block 90 is formed so as to gradually incline toward the root from the surface of the block 90 toward the stepping side of the block 90 (the direction of the arrow A in FIG. 7). The inclination angle is the largest at the tire width direction central portion 98M, and the tire width direction central portion 98M has a maximum value of the angular fluctuation. The position of the maximum value can be calculated by partially differentiating the equation representing the angular fluctuation of the widthwise wall surface 98, and the maximum value can be calculated by substituting the calculation result into the equation. However, in the case of a non-differentiable change, the only extreme value is the minimum value or the maximum value that is limited to one point other than the end on that side.

As described above, the width direction wall surface 98 of the block 90 on the stepping edge side (the arrow A direction in FIG. 7) has the inclination angle outside the tire width direction (the arrow C direction in FIG. 7) and the tire width. It is formed so as to gradually increase from the inner side in the direction (on the side of the arrow D in FIG. 7) toward the tire width direction central portion 98M. The inclination angle monotonically increases when viewed from the tire width direction outer end portion and the tire width direction inner end portion, and monotonically decreases when viewed from the tire width direction center portion 98M.

Therefore, in the block 90 of the pneumatic tire of this embodiment, the block 90 is the portion of the block 90 on the stepping edge side (direction of arrow A in FIG. 7).
7, the tire width direction outer side portion (arrow C direction side in FIG. 7) and the tire width direction inner side portion (arrow D direction in FIG. 7) have relatively low compression rigidity, and the tire width direction central portion 98M has relatively compression rigidity. Is high. In addition, a portion of the block 90 on the kicking edge side (the arrow B direction side in FIG. 7), that is, a tire width direction outer side portion (the arrow C direction in FIG. 7) and a tire width direction inner side portion (FIG. 7) of the block 90. The middle arrow D side) has relatively high compression rigidity, and the tire width direction central portion 96M has relatively low compression rigidity.

Next, the operation and effect of the pneumatic tire of this embodiment will be described.

According to the pneumatic tire of the present invention, the compression rigidity of the block 90 can be changed along the tire width direction, so that the load input speed at the tire width direction outer side portion of the block 90 to the tire can be reduced. The transmission speed of the load input to the tire in the tire width direction central portion, the transmission speed of the load input to the tire in the tire width direction inner portion of the block 90, and the transmission speed of the load input to the tire in the tire width direction central portion. Can be made different. As a result, noise (pattern noise) can be reduced.

[Sixth Embodiment] Next, a pneumatic tire according to a sixth embodiment of the present invention will be described.

The same components as those of the pneumatic tires of the fourth and sixth embodiments are designated by the same reference numerals and the description thereof will be omitted as appropriate.

As shown in FIG. 8, in the pneumatic tire of this embodiment, the circumferential wall surface 112 on the tire width direction outer edge side (the arrow C direction side in FIG. 8) of the block 110 is the same as that of the fourth embodiment. Similar to the block 70 of the filled tire, it is formed so that the variation of the inclination angle of the circumferential wall surface 112 with respect to the tire radial direction has only one minimum value.

On the other hand, the circumferential wall surface 114 of the inner edge of the block 110 in the tire width direction (the direction of the arrow D in FIG. 8) is also
Like the block 70 of the pneumatic tire of the fourth embodiment, the variation in the inclination angle of the circumferential wall surface 114 with respect to the tire radial direction is formed so as to have only one maximum value.

The widthwise wall surface 116 of the block 110 on the kicking edge side (the direction of the arrow B in FIG. 8) has a tire diameter of the widthwise wall surface 116, which is similar to the block 90 of the pneumatic tire of the fifth embodiment. It is formed so that the variation of the tilt angle with respect to the direction has only one local minimum value.

On the other hand, the widthwise wall surface 118 of the block 110 on the stepping edge side (direction of the arrow A in FIG. 8) is also in the tire radial direction of the widthwise wall surface 118, similarly to the block 90 of the pneumatic tire of the fifth embodiment. It is formed so that the variation of the tilt angle with respect to has only one maximum value.

Also in the pneumatic tire of this embodiment,
The compressive rigidity of the block 110 changes along the tire width direction.

Next, the function and effect of the pneumatic tire of this embodiment will be described.

Also in the pneumatic tire of the present invention, a difference is provided between the transmission speed of the load input to the tire at the tire width direction outer side portion and the transmission speed of the load input to the tire at the tire width direction inner side portion. Therefore, noise (pattern noise) can be reduced.

(Test Example) Next, a noise test using the pneumatic tire of the present invention and a conventional tire will be described.

The tires tested were all provided with a tread pattern (mono pattern) as shown in FIG. As a test tire size, 195 / 65R
The block size was 15, and the tire circumferential direction length was 30 mm, the tire width direction length was 20 mm, and the block height was 10 mm.

As a test, the sound pressure at a speed of 80 km / h was measured and expressed as an index.

The test results are shown in Tables 1 and 2 below.
It became as shown in.

Here, "Conventional Example 1" in Table 1 below is a block in which the inclination angle of each wall surface with respect to the tire radial direction is unified to 10 degrees.

The "embodiment 1" is the block 18 shown in FIG.
A pneumatic tire 1 according to a first embodiment of the present invention including
It is 0. The maximum inclination angle of the circumferential wall surfaces 24, 26 is 2
It was 0 degree and the minimum was 0 degree (not tilted).

The "embodiment 2" is the block 30 shown in FIG.
It is a pneumatic tire according to a second embodiment of the present invention, which is equipped with. The maximum inclination angle of the width direction wall surfaces 36 and 38 was set to 20 degrees, and the minimum inclination angle was set to 0 degrees (not inclined).

The "third embodiment" is the block 50 shown in FIG.
Is a pneumatic tire according to a third embodiment of the present invention, which is equipped with. Circumferential wall surfaces 52, 54 and width wall surfaces 56, 58
The maximum inclination angle of was set to 20 degrees and the minimum was set to 0 degrees (not inclined).

The "fourth embodiment" is the block 70 shown in FIG.
It is a pneumatic tire according to a fourth embodiment of the present invention which is equipped with.

The "fifth embodiment" is the block 90 shown in FIG.
It is a pneumatic tire according to a fifth embodiment of the present invention which is equipped with.

The "sixth embodiment" is the block 11 shown in FIG.
It is a pneumatic tire according to a sixth embodiment of the present invention having 0.

"Embodiment 7" is a pneumatic tire provided with the block of Embodiment 3 shown in FIG. 5, in which the change in the inclination angle of the wall surface of the block is 5 degrees.

"Embodiment 8" is a pneumatic tire including the block of Embodiment 3 shown in FIG. 5, in which the change in the inclination angle of the wall surface of the block is 10 degrees.

[Embodiment 9] is a pneumatic tire including the block of Embodiment 3 shown in FIG. 5, in which the change in the inclination angle of the wall surface of the block is 30 degrees.

"Example 10" is a pneumatic tire equipped with the block of Example 3 shown in FIG. 5, in which the inclination angle of the wall surface of the block is changed to 35 degrees.

The numerical values in Tables 1 and 2 are the values of Conventional Example 1
Is expressed as an index with reference to (100). The smaller the numerical value in the table, the better.

The desired level here was set to 10 points or more, which is considered to be superior in products. Therefore, it can be said that the noise is improved if there is a difference of 10 points or more from the conventional example 1.

[0188]

[Table 1]

[0189]

[Table 2]

As shown in Tables 1 and 2, it was found that the noises were reduced in Examples 1 to 10 of the present invention as compared with Conventional Example 1.

In particular, as shown in Table 2 and FIG. 9, when the change in the inclination angle of the wall surface of the block is in the range of 10 degrees or more and 30 degrees or less, the noise is improved by 10 points or more as compared with the conventional example 1. It turned out that Therefore, it can be said that the pneumatic tire including the block in which the change in the inclination angle of the wall surface is in the range of 10 degrees or more and 30 degrees or less is superior as a product.

[0192]

According to the pneumatic tire of the present invention, noise can be reduced without changing the two-dimensional pattern design.

[Brief description of drawings]

FIG. 1 is a plan view showing a tread pattern of a pneumatic tire of the present invention.

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

FIG. 3 is a cross-sectional view of each block of the pneumatic tire according to the first embodiment of the present invention.

FIG. 4 is a plan view of a block of a pneumatic tire according to a second embodiment of the present invention.

FIG. 5 is a plan view of a block of a pneumatic tire according to a third embodiment of the present invention.

FIG. 6 is a plan view of a block of a pneumatic tire according to a fourth embodiment of the present invention.

FIG. 7 is a plan view of a block of a pneumatic tire according to a fifth exemplary embodiment of the present invention.

FIG. 8 is a plan view of a block of a pneumatic tire according to a sixth embodiment of the present invention.

FIG. 9 is a graph showing the contents shown in Table 2 with an index on the vertical axis and a width of angle change on the horizontal axis.

FIG. 10 is a conceptual diagram showing a change in inclination angle of a block in a conventional pneumatic tire.

[Explanation of symbols]

10 pneumatic tires 14 circumferential groove 16 lug groove (tilt groove) 18 blocks 24 circumferential wall 26 Circumferential wall 30 blocks 36 Width direction wall surface (tilt direction wall surface) 38 Width direction wall surface (tilt direction wall surface) 50 blocks 52 Circumferential wall 54 Circumferential wall 56 Width direction wall surface (tilt direction wall surface) 58 Width direction wall surface (tilt direction wall surface) 70 blocks 72 Width direction wall surface (tilt direction wall surface) 74 Width direction wall surface (tilt direction wall surface) 76 Circumferential wall 78 Circumferential wall 90 blocks 92 Circumferential wall 94 Circumferential wall 96 width direction wall surface (tilt direction wall surface) 98 Width direction wall surface (tilt direction wall surface) 110 blocks 112 circumferential wall 114 circumferential wall 116 Width direction wall surface (tilt direction wall surface) 118 Width direction wall surface (tilt direction wall surface)

Claims (11)

[Claims] 1. A plurality of circumferential grooves extending substantially in the tire circumferential direction, a plurality of inclined grooves extending obliquely with respect to the tire circumferential direction, and a plurality of blocks partitioned by the circumferential grooves and the inclined grooves. And a pneumatic tire having, wherein the inclination angle of the circumferential wall surface extending along the circumferential groove of the block with respect to the tire radial direction is changed over the tire circumferential direction, and the stepping edge of the block or A pneumatic tire characterized in that the compression rigidity of the block is changed in the tire width direction from one of the kick-out edges to the other. 2. A plurality of circumferential grooves extending substantially in the tire circumferential direction, a plurality of inclined grooves extending obliquely with respect to the tire circumferential direction, and a plurality of blocks partitioned by the circumferential grooves and the inclined grooves. And a tire width direction outer end of the block, in which the inclination angle with respect to the tire radial direction of the inclination direction wall surface extending along the inclination groove of the block is changed over the tire width direction. A pneumatic tire characterized in that the compression rigidity of the block is changed in the tire width direction from one of the edge or the inner edge in the tire width direction to the other. 3. A plurality of circumferential grooves extending substantially in the tire circumferential direction, a plurality of inclined grooves extending obliquely with respect to the tire circumferential direction, and a plurality of blocks partitioned by the circumferential grooves and the inclined grooves. And a pneumatic tire having, wherein the inclination angle of the circumferential wall surface extending along the circumferential groove of the block with respect to the tire radial direction is changed over the tire circumferential direction, and the stepping edge of the block or The compression rigidity of the block is changed in the tire width direction from one of the kick-out edges to the other, and the inclination angle of the inclined wall surface extending along the inclined groove of the block with respect to the tire radial direction is set in the tire width direction. The compression rigidity of the block is changed in the tire width direction from one of the tire width direction outer edge or the tire width direction inner edge of the block to the other. Pneumatic tire to. 4. The pneumatic tire according to claim 1, wherein the variation of the inclination angle of the circumferential wall surface of the block with respect to the tire radial direction monotonically increases or decreases along the tire circumferential direction. tire. 5. The pneumatic tire according to claim 2, wherein the variation of the inclination angle of the inclined wall surface of the block with respect to the tire radial direction is monotonically increased or decreased along the tire width direction. tire. 6. The variation of the inclination angle of the circumferential wall surface of the block with respect to the tire radial direction monotonically increases or decreases along the tire circumferential direction. The pneumatic tire according to claim 3, wherein the variation of the inclination angle monotonically increases or decreases along the tire width direction. 7. The circumferential wall surface of the block is formed such that the variation of the inclination angle of the circumferential wall surface with respect to the tire radial direction has only a minimum value or a maximum value. Item 1. The pneumatic tire according to Item 1. 8. The inclined wall surface of the block is formed so that the variation of the inclination angle of the inclined wall surface with respect to the tire radial direction has only a minimum value or a maximum value. Item 3. The pneumatic tire according to Item 2. 9. The circumferential wall surface of the block is formed such that the variation of the tilt angle of the circumferential wall surface with respect to the tire radial direction has only a minimum value or a maximum value. The pneumatic tire according to claim 3, wherein the variation of the inclination angle of the wall surface in the inclination direction with respect to the tire radial direction is formed so as to have only one minimum value or maximum value. 10. The tilt angle of the circumferential wall surface of the block with respect to the tire radial direction or the tilt angle of the block wall surface of the block with respect to the tire radial direction changes smoothly. The pneumatic tire according to any one of items 1 to 9. 11. The difference between a portion of the circumferential wall surface of the block having a large inclination angle with respect to the tire radial direction and a portion having a small inclination angle thereof is 10 degrees or more and 30 degrees or less, and the tire radial direction of the inclination wall surface of the block The difference between a portion having a large inclination angle and a portion having a small inclination angle with respect to is not less than 10 degrees and not more than 30 degrees.
The pneumatic tire according to any one of 0.