JP2002002233A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase abrasion resistance in response to a difference, generated by a difference in the placing position of a tire, in the input direction of external forces. SOLUTION: An outside block 18 formed in a parallelogram shape is disposed outside a front tire 10A. An inside block 20 formed in the parallelogram shape is disposed inside the front tire 10A. A sipe 26 is installed on a one-by-one basis in the blocks 18 and 20, respectively, and the central main part 26A of the sipe 26 installed in the blocks 18 and 20 is formed in such a manner as to extend along the diagonals of the blocks 18 and 20 slantingly relative to an equatorial plane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire having improved tire life by suppressing uneven wear of a tread, and is particularly suitable for an ultra-high performance tire for a passenger car.

[0002]

2. Description of the Related Art Conventionally, among radial tires for passenger cars which are pneumatic tires, blocks are arranged in a tread of a tire serving as a tread portion in contact with a road surface, for example, for use in an ultra-high performance passenger car. Those having a block type tread pattern are known. The sipe is formed on the land portion, which is a block formed on the tread of the pneumatic tire, so that the sipe is formed almost perpendicularly to the surface of the land portion from the surface of the land portion toward the groove bottom. Was provided.

[0003]

However, in the case of an ultra-high-performance passenger car, the rotation direction is specified and the size of the front and rear wheels is different, so that in many cases, tire rotation cannot be performed at all. The condition is such that the tire is likely to continue receiving the force in the direction. For this reason, in the conventional sipe formed in the vertical direction, uneven wear occurs as the wear of the block progresses only in the direction specified by the tire mounting position due to the fall of the block around the sipe. There was a trend.

The present invention has been made in view of the above circumstances, and has as its object to provide a pneumatic tire capable of improving abrasion resistance in response to a difference in an input direction of an external force caused by a difference in a mounting position of a tire.

[0005]

A pneumatic tire according to claim 1 is a pneumatic tire in which a block having at least one sipe formed to be inclined with respect to an equatorial plane is arranged on a tread portion. The central main portion of the sipe is formed by tilting the groove bottom side in the direction of the main stress from the road surface acting on the block with reference to the surface side of the block.

The operation of the pneumatic tire according to claim 1 will be described below. The present invention is used for a pneumatic tire having a block-based pattern in which a block having at least one sipe formed to be inclined with respect to an equatorial plane is arranged on a tread portion. Further, the central main portion of the sipe is formed by inclining the groove bottom side in the direction of the largest main stress among the external forces acting on the block from the road surface with reference to the surface side of the block.

Normally, although the input direction of the external force differs depending on the mounting position of the tire, the rotation of the tire is completely impossible in an ultra-high performance passenger car using the pneumatic tire according to the present invention. Abrasion proceeds only in a specific direction determined for each position, and tends to cause uneven wear. However, in the present invention, the central main portion of the sipe is formed to be inclined toward the groove bottom, so that the rigidity of the block around the sipe changes and uneven wear can be suppressed.

That is, since uneven wear is considered to be caused by the block falling around the sipe, the central main portion of the sipe is inclined toward the direction of the largest principal stress among the external forces acting on the block from the road surface. Thus, the rigidity of the block around the sipe, which had fallen toward the sipe due to external force, was increased, and it was possible to suppress uneven wear by suppressing the block from falling down. As a result, since the position where the sipe is arranged and the size (volume) of the groove forming the sipe are the same as those of the conventional tire, the tire mounting position is maintained with the same dry grip and wet grip as the conventional tire. The wear resistance is increased in response to the difference in the input direction of the external force caused by the difference in the tire force, and the life of the tire can be extended.

The operation of the pneumatic tire according to claim 2 will be described below. The present invention is used for a pneumatic tire having at least one sipe and a block-based pattern in which a substantially quadrangular block is arranged on a tread portion. Further, the central main portion of the sipe extends along the diagonal line of the block and is formed so that the groove bottom is inclined in the direction of the main stress from the road surface acting on the block with reference to the surface side of the block. .

Therefore, the block is formed in a substantially quadrilateral shape, and the central main portion of the sipe is formed so as to extend along the diagonal line of this block. With the same dry grip and wet grip secured, the wear resistance is increased in response to the difference in the input direction of the external force caused by the difference in the mounting position of the tire, resulting in a longer tire life Now you can.

The operation of the pneumatic tire according to claim 3 will be described below. The present invention has the same structure as that of the first and second aspects and operates in the same manner. However, the traction force is used for a wheel having a main stress, and the central main part of the sipe is provided on the surface side of the block. The groove bottom is inclined in the direction of the traction force with respect to the traction force. In other words, the present invention limits the configuration in the case where the pneumatic tire is used for the drive wheel, and in this case, the central main part of the sipe formed diagonally at the center of the block is oriented in the direction of the traction force. Leaning.

As a result, the rigidity of the block, which has conventionally fallen toward the sipe by the traction force, has been increased, and the fall of the block in the circumferential direction of the tread portion has been suppressed. Therefore, the corners of the blocks remaining without being worn without contacting the ground due to the fall due to the traction force are more uniformly worn with the surroundings, so that uneven wear can be further suppressed.

The operation of the pneumatic tire according to claim 4 will be described below. The present invention has the same structure as that of the first and second aspects and operates in the same manner. However, the present invention is further applied to a wheel in which a braking force is a main stress, and a central main portion of the sipe is provided on a surface of the block. The groove bottom is inclined in the direction of the braking force with respect to the side. In other words, the present claim limits the configuration in the case where the pneumatic tire is used for a non-driving wheel that is a play wheel, and in this case, the central main portion of the sipe arranged diagonally at the center of the block is: Since it is inclined in the direction of the braking force, the effect of suppressing uneven wear can be obtained as in the third aspect.

The operation of the pneumatic tire according to claim 5 will be described below. In the present invention, the pneumatic tire of claim 3 is used for a rear wheel, and the pneumatic tire of claim 4 is used for a front wheel. That is, by mounting the pneumatic tire in combination with a vehicle such as a rear-wheel-drive passenger car as in the present invention, the effects of these claims can be more reliably achieved.

The operation of the pneumatic tire according to claim 6 will be described below. The present invention has the same structure as that of the first to fifth aspects and operates in the same manner. However, the block is formed in a substantially rhombic shape, and the central main portion of the sipe is formed on the short side of the diagonal line of the block. It is configured to be arranged to extend along. In other words, even when the blocks are formed in the shape of a rhombus whose parallel sides are equal to each other in the parallelogram as in the present invention, the same effect as in the first embodiment can be obtained.

The operation of the pneumatic tire according to claim 7 will be described below. The present invention has the same structure as that of claims 1 to 6 and operates in the same manner, but furthermore, the inclination angle of the inclination of the central main portion of the sipe is in the range of 5 ° to 45 °. It has a configuration. In other words, if the angle of inclination is less than 5 °, the rigidity of the blocks around the sipe is not sufficiently increased, so that uneven wear cannot be suppressed. The life of the mold is shortened, and it becomes difficult to manufacture a pneumatic tire. Therefore, the inclination angle of the inclination of the central main portion of the sipe is within the above range.

The operation of the pneumatic tire according to claim 8 will be described below. In the present invention, the pneumatic tire is provided as a plurality of block rows including a plurality of blocks and is used as a tire for a steered wheel. Furthermore, the central main portion of the sipe formed on the block of the outer block row when the vehicle is mounted is formed to be inclined in the direction of the side force, and the sipe formed on the block of the inner block row when the vehicle is mounted. The central main portion is formed to be inclined in the direction of the braking force.

Therefore, since the side force and the braking force are the main stresses acting on the block from the road surface, the same dry grip as that of the conventional tire can be obtained even for a steering wheel tire. With the wet grip secured, the abrasion resistance is increased in response to the difference in the input direction of the external force, and a longer life of the tire can be achieved.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A pneumatic tire according to one embodiment of the present invention will be described with reference to the drawings. 1 and 5 are views showing a typical example of a tread pattern of the pneumatic tires 10A and 10B according to the present embodiment. Here, as for the internal structure of the pneumatic tires 10A and 10B, as shown in FIGS. 2 and 6, a carcass 12 which is a radial carcass and a highly rigid belt arranged so as to cover a crown portion of the carcass 12 (Not shown) and a tread 14 composed of tread rubber and arranged on the outer peripheral surface of the belt are very common as a pneumatic tire of this type in combination. I do.

Further, as shown in FIGS. 1, 2, 5 and 6, the above-described tread having a crown-shaped outer surface formed on its outer surface in contact with the road surface of the pneumatic tires 10A and 10B. The shoulder portion 16 forms both end portions of the tread 14.

FIG. 1 of these drawings shows a front tire 10A which is a pneumatic tire on the steered wheel side. As shown in the figure, an outer tread pattern, which is an outer side when the vehicle is mounted, is disposed on the left side of the center line CL which is the equatorial plane of the tread 14 of the front tire 10A. On the right side, an in-side tread pattern which is an inner side when the vehicle is mounted is arranged.

That is, on the out side of the front tire 10A, a pair of widthwise sides 18 each extending in the circumferential direction are provided.
A and a pair of oblique sides 18B that are inclined in the tire rotation direction R when extending from the shoulder portion 16 toward the center line CL and extend from the upper left side to the lower right side in FIG. Out side block 18 is disposed.
In the present embodiment, a plurality of these out side blocks 18
Are arranged at equal intervals over one circumference of the tread 14, and three rows of block rows composed of these out-side blocks 18 are formed side by side in the tire width direction.

On the other hand, on the in side of the front tire 10A, a pair of widthwise sides 20A each extending in the circumferential direction are provided.
And a pair of oblique sides 20B that are inclined in the tire rotation direction R from the shoulder portion 16 toward the center line CL and extend from the upper right side to the lower left side in FIG. 1 to form a parallelogram-shaped outline. Side blocks 20 are arranged. In the present embodiment, a plurality of these in-side blocks 20 are arranged at equal intervals over one circumference of the tread 14, and three rows of block rows composed of these in-side blocks 20 are formed side by side in the tire width direction. .

Grooves 24 are formed between the outer blocks 18, between the inner blocks 20, and between the outer blocks 18 and the inner blocks 20, respectively. The tread pattern of the front tire 10A is the out side block 18.
And the in-side block 20. Further, each of the out-side block 18 and the in-side block 20 is provided with a single sipe 26 as a narrow groove, and a central main sipe 26 of the out-side block 18 and the in-side block 20 is provided. A portion 26A is formed so as to extend along a diagonal line of these blocks 18 and 20 and to be inclined with respect to the equatorial plane.

In the out-side block 18 shown in FIG. 3, the center of the sipe 26 is moved toward the inside in the tire width direction on which the side force SF acting as the main stress from the road surface acting on the out-side block 18 is directed. The groove bottom 26C side of the sipe 26 is arranged so as to be inclined with respect to a portion of the main portion 26A on the surface side of the block. Further, in the in-side block 20 shown in FIG. 4, the central main portion 26 </ b> A of the sipe 26 is moved in the direction of the braking force BF along the tire rotation direction R, which is the main stress from the road surface acting on the in-side block 20. The groove bottom 26C side of the sipe 26 is arranged to be inclined with respect to the surface side portion of the block in FIG. The range of the inclination angle θ of the central main portion 26A of the sipe 26 with respect to the vertical line V shown in FIGS. 3 and 4 is preferably from 5 ° to 45 °, and more preferably from 15 ° to 25 °.

FIG. 5 shows a rear tire 10B which is a pneumatic tire on the driving wheel side. As shown in this figure, symmetric tread patterns are arranged on the left and right sides of the center line CL of the tread 14 of the rear tire 10B. That is, a pair of widthwise sides 2 extending in the circumferential direction are provided on the left and right sides of the center line CL of the rear tire 10B.
A block 22 is formed in which a parallelogram is formed by 2A and a pair of sloping sides 22B that extend from the shoulder 16 toward the center line CL while being inclined in the tire rotation direction R. In the present embodiment, a plurality of these blocks 22 are arranged at equal intervals around one circumference of the tread 14, and a block row composed of these blocks 22
Each of the three rows is formed in the tire width direction with L interposed therebetween.

And, between these blocks 22,
Each of the grooves 24 is formed, and the tread pattern of the rear tire 10B according to the present embodiment has a structure in which these blocks 22 are combined. Further, each of the blocks 22 is provided with one sipe 26 which is a narrow groove, and a central main portion 26A of the sipe 26 provided in each of the blocks 22 is arranged along a diagonal line of the block 22 and along the equatorial plane. It is formed to extend obliquely with respect to.

In the block 22 shown in FIG. 7, the traction force TF, which is the main stress acting on the block 22 from the road surface, is directed toward the side where the traction force TF is directed. The groove bottom 26C side of the sipe 26 is inclined with respect to the portion. The range of the inclination angle θ of the central main portion 26A of the sipe 26 with respect to the vertical line V shown in FIG.
An even more preferred angle is between 25 ° and 25 °.

On the other hand, these pneumatic tires 10A, 10A
Sipe 26 provided in blocks 18, 20, and 22 of B
As shown in FIGS. 1 and 5, both end portions 26B extend in parallel with the oblique sides 18B, 20B, 22B of the block, respectively, and extend in the width direction sides 18A, 20A, 22 of the block, respectively.
A has been reached.

Next, the operation of the pneumatic tires 10A and 10B according to the present embodiment will be described below. The pneumatic tires 10A and 10B according to the present embodiment have one sipe 26 formed to be inclined with respect to the equatorial plane, and blocks 18, 20, and 22 formed in a substantially quadrilateral are arranged on the tread 14. It has such a block-based pattern. A central main portion 26A of the sipe 26 is formed so as to extend along a diagonal line of each of the blocks 18, 20, 22. Further, the central main portion 26A of the sipe 26 is formed on the surface of the block 18, 20, 22. The groove bottom 26C is formed so that the groove bottom 26C is inclined in the direction of the main stress from the road surface acting on the blocks 18, 20, 22 with respect to the side.

For example, in the out-side block 18 of the front tire 10A, the central main portion 26A of the sipe 26 is directed toward the side force SF shown in FIG.
In the in-side block 20 of the front tire 10A, the central main portion 26A of the sipe 26 is arranged to be inclined toward the direction of the braking force BF shown in FIG. I have. In the rear tire 10B, the central main portion 26 of the sipe 26 is oriented toward the traction force TF shown in FIG.
A is inclined.

Accordingly, it is considered that the rotation of the tire is completely impossible in an ultra-high performance passenger car, and the wear tends to progress only in a specific direction determined for each mounting position of the tire to cause uneven wear. In the embodiment, the central main portion 26A of the sipe 26 is formed so as to extend along the diagonal of the blocks 18, 20, and 22 formed in a substantially quadrilateral. Then, in the direction of the main stress from the road surface acting on this block, the central main portion 26 of this sipe 26
By forming A inclining toward the groove bottom 26C, the rigidity of the blocks 18, 20, and 22 around the sipe 26 changes, and uneven wear can be suppressed.

In other words, since uneven wear is considered to be caused by the block falling around the sipe, the central main portion of the sipe is inclined in the direction of the main stress from the road surface acting on the block to provide a chamfered portion. By doing so, the rigidity of the block around the sipe, which had fallen toward the sipe due to external force, has been increased, and accordingly, the fall of the block has been suppressed, and uneven wear can be suppressed.

As a result, according to the pneumatic tires 10A and 10B according to the present embodiment, the position at which the sipe 26 is arranged and the groove volume, which is the size of the groove constituting the sipe 26, are not different from those of the prior art. With the same dry grip and wet grip as conventional tires,
Wear resistance is increased in response to the difference in the input direction of the external force caused by the difference in the mounting position of the tire, and accordingly, the life of the tire can be extended.

At this time, in the present embodiment, the inclination angle θ of the inclination of the central main portion 26A of the sipe 26 is in the range of 5 ° to 45 °. That is, the inclination angle θ
Is less than 5 °, the rigidity of the block around the sipe is not sufficiently increased, so that uneven wear cannot be suppressed, and when the inclination angle θ exceeds 45 °, the tire vulcanizing die Since the life is shortened and it becomes difficult to manufacture the pneumatic tire, the inclination angle θ of the inclination of the central main portion 26A of the sipe 26 is set in the range of 5 ° to 45 °.

Specifically, when the pneumatic tire according to the present embodiment is used as the rear tire 10B which is the driving wheel whose traction force TF is the main stress, the sipe 26 arranged diagonally at the center of the block 22 is used. The central main portion 26A has a structure in which the groove bottom 26C is inclined in the direction of the traction force TF with reference to the surface side of the block 22 as described above. As a result, the rigidity of the block 22 which has conventionally fallen toward the sipe 26 by the traction force TF is increased, and the tread 14
Of the block in the circumferential direction has been suppressed. Therefore, the corners of the block 22, which have been left without abrasion without contact with the ground due to the fall by the traction force TF, are more uniformly worn with the surroundings, and uneven wear can be further suppressed.

When the pneumatic tire according to the present embodiment is used as a front tire 10A as a steering wheel tire, the sipe disposed on the outer block 18 of the outer block row when the vehicle is mounted as described above. 26 is inclined toward the direction of the side force SF, and the central main portion 26A of the sipe 26 arranged on the in-side block 20 of the inner block row when the vehicle is mounted is:
It is inclined toward the direction of the braking force BF.

As a result, the central main portion 26A of the sipe 26 disposed diagonally at the center of the blocks 18 and 20 has a side force SF and a braking force with respect to the portion of the sipe 26 on the surface side of the blocks 18 and 20. Force BF
, The groove bottom 26C side of the sipe 26 is inclined, so that the effect of suppressing uneven wear can be obtained.

Next, the results of a running test performed by comparing the pneumatic tire described in the present embodiment with the tire according to the conventional example will be described below. That is, in the conventional example shown in FIG. 8, the sipe 1 is formed so as to be formed almost perpendicularly to the surface of the block from the surface of the block toward the groove bottom.
26 is a pneumatic tire provided. On the other hand, in the embodiment shown in FIG. 9, the groove bottom side is inclined in the direction of the main stress with respect to the surface side of the block, and
6A is a pneumatic tire formed with 6A.

Here, between the shape of the new state N indicated by the dotted line and the shape of the used state M after traveling indicated by the solid line in the blocks divided by the sipes 26 and 126, The difference between the amount S _MAX and the amount of wear S _MIN at the place where the amount of wear is least (the part facing the sipe remaining without being worn due to the block falling down) is defined as the uneven wear amount S.

That is, the uneven wear amount S is given by S = S _MAX -S
It is calculated from the formula of _MIN , and from the result of running test performed by mounting each tire as described above on the vehicle, the uneven wear amount S of the conventional example is set to 0.7 mm, and the uneven wear amount S of the embodiment is set to 0.7 mm. Was 0.5 mm. Based on the above results, if the uneven wear amount S is indexed and the uneven wear amount S in the conventional block is set to 100, the uneven wear amount S in the block of the embodiment is 7
1, which indicates that the tire life was improved as compared with the conventional example. The size of the tire used in the running test is 225 / 45R17, the vehicle used in the running test is a domestic high-performance passenger car, the internal pressure of the tire is 220 KPa, and the running distance is Was 20,000 km.

Although the block is a parallelogram in the above embodiment, a block is formed in the shape of a rhombus of which the lengths of the four sides are equal to each other, and the central main portion of the sipe is formed by the block. You may arrange | position so that it may extend along the short side of a diagonal line. That is, even when the block is formed in a substantially rhombic shape, similarly to the above-described embodiment, the wear resistance is increased in response to the difference in the input direction of the external force caused by the difference in the mounting position of the tire, and the long tire is provided. Life can be achieved. Although one sipe is used in the above embodiment, two or more sipes may be formed in each block.

[0043]

As described above, the pneumatic tire of the present invention has an excellent effect that the wear resistance can be improved corresponding to the difference in the input direction of the external force caused by the difference in the mounting position of the tire.

[Brief description of the drawings]

FIG. 1 is a development view showing a tread of a front tire according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG.

FIG. 3 is a sectional view taken along line 3-3 of FIG.

FIG. 4 is a sectional view taken along line 4-4 of FIG. 1;

FIG. 5 is a development view showing a tread of the rear tire according to one embodiment of the present invention.

FIG. 6 is a transverse sectional view taken along the line 6-6 in FIG. 5;

FIG. 7 is a sectional view taken along line 7-7 of FIG. 5;

FIG. 8 is an explanatory diagram illustrating a wear amount of a block in a conventional tire.

FIG. 9 is an explanatory diagram illustrating a wear amount of a block in the tire of the example.

[Explanation of symbols]

 10A Front tire 10B Rear tire 14 Tread 16 Shoulder part 18 Out side block 20 In side block 22 Block 26 Sipe 26A Central main part

Claims (8)

[Claims] 1. A pneumatic tire in which a block having at least one sipe formed to be inclined with respect to an equatorial plane is arranged on a tread portion, and a central main portion of the sipe is referenced to a surface side of the block. The pneumatic tire is formed by tilting a groove bottom side in a direction of a main stress from a road surface acting on the block. 2. The pneumatic tire according to claim 1, wherein the block is formed in a substantially quadrilateral, and a central main portion of the sipe extends along a diagonal line of the block. 3. A traction force is used for a wheel having a main stress, and a central main portion of the sipe is formed by inclining a groove bottom side in a direction of the traction force with reference to a surface side of the block. The pneumatic tire according to claim 1 or 2, wherein: 4. A braking force is used for a wheel having a main stress, and a central main portion of the sipe is formed by inclining a groove bottom side in a direction of the braking force with respect to a surface side of the block. The pneumatic tire according to claim 1 or 2, wherein: 5. A pneumatic tire, wherein the pneumatic tire according to claim 3 is used for a rear wheel, and the pneumatic tire according to claim 4 is used for a front wheel. 6. The block according to claim 1, wherein the block is formed in a substantially diamond shape, and a central main portion of the sipe is arranged to extend along a short side of a diagonal line of the block.
The pneumatic tire according to any one of claims 1 to 5. 7. The pneumatic tire according to claim 1, wherein the inclination angle of the central main portion of the sipe is in a range of 5 ° to 45 °. 8. A plurality of block rows composed of a plurality of blocks are provided and used as steering wheel tires. A central main portion of a sipe formed in a block of the block row on the outside when the vehicle is mounted is a side force of a side force. A pneumatic tire, wherein a central main portion of a sipe formed in a block of the block row on the inner side when mounted on a vehicle is formed to be inclined in a direction of a braking force.