JP2003170705A - Pneumatic tire and its mounting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire and its mounting method capable of reconciling maneuvering stability with WET performance and minimizing abrasion difference between the outside tread and the inside tread. <P>SOLUTION: A difference between a negative ratio of the outside tread OT and that of the inside tread IT is 5% or less, so that abrasion difference between the treads can be minimized. A circumferential continuous center rib 14 is offset and disposed outside a vehicle, so that occurrence of buckling can be minimized in a tread central part in cornering and reduction of the maneuvering stability can be prevented. The number of pitches of width-directional lateral grooves 28 is between 40 and 60, so that drainage on a WET road surface becomes high. In the outside tread OT, each of big blocks 34 is constituted of a body part 36 and an extending part 38 and the number of pitches of the big blocks 34 is set 1/3 or less of the number of pitches of the width-directional lateral grooves 28, so that reduction of the drainage can be prevented and pattern rigidity and the maneuvering stability can be improved. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a tire equatorial line CL.
The invention relates to a pneumatic tire having an asymmetrical tread pattern in which an outer tread pattern located on the vehicle mounting outer side and an inner tread pattern located on the vehicle mounting inner side are different from each other, and a mounting method thereof.

[0002]

2. Description of the Related Art Among conventional pneumatic tires, pneumatic tires having an asymmetric tread pattern for the purpose of achieving both steering stability and WET performance are known. In this pneumatic tire, the outer tread located on the vehicle mounting outer side and the inner tread located on the vehicle mounting inner side are different from each other with reference to the tire equator line CL.

Here, regarding such a pneumatic tire,
For example, the following technologies are known.

First, by making the negative ratio of the outer tread smaller than the negative ratio of the inner tread, the actual ground contact area of the outer tread is increased to improve the steering stability on dry road surface and the negative ratio. Large inner tread ensures WET performance.

The "negative rate" is a value obtained by multiplying the value obtained by dividing the groove area by the total ground contact area (including the groove area) of the tire by 100.

Secondly, by making the number of pitches of land portions formed on the outer tread smaller than the number of pitches of land portions formed on the inner tread, the pattern rigidity of the outer tread is increased and steering stability is improved. As well as improve
WET performance is secured in the inner tread.

However, from the viewpoint that the functions are shared by the tread halves due to asymmetry, it is effective to make the pattern configurations of the outer tread and the inner tread largely different, but the difference in the actual ground contact area or the pattern rigidity There is another problem that the difference in wear based on the difference becomes large.

Therefore, although the asymmetric tread pattern as described above is applied to racing vehicles and some high-performance vehicles, there is a problem in practicality, and a general vehicle traveling on a general road is asymmetrical. The reality is that the benefits of the tread pattern have not been fully enjoyed.

[0009]

Therefore, in consideration of the above facts, the present invention seeks to achieve both steering stability and WET performance, and to minimize the difference in wear between the outer tread and the inner tread with reference to the tire equator line. An object of the present invention is to provide a pneumatic tire that can be reduced in size and a method for mounting the pneumatic tire.

[0010]

The pneumatic tire according to claim 1, wherein the pneumatic tire has a tread pattern that is asymmetrical with respect to the tire equator line, and is one of the tire widthwise directions with respect to the tire equator line. The difference between the negative rate of the one side tread located on the side and the negative rate of the other side tread located on the other side in the tire width direction based on the tire equator is 5% or less, and 5% or more of the tread width of all treads. It has a rib width of 20% or less, is arranged offset to one side in the tire width direction with respect to the tire equator line, and is continuous in the tire circumferential direction in which the offset amount from the tire equator line of the center line is less than the rib width. A plurality of circumferentially continuous center ribs, and the plurality of treads are formed on the other side tread at intervals in the tire circumferential direction and extend toward the tire width direction outer end portion. The number of blocks having lateral grooves and the pitch formed by the lateral grooves is 40 or more and less than 60, the one-side tread has a block row composed of large blocks and small blocks, and the large blocks include: A main body portion arranged on the outer side in the tire width direction, and an extension portion connected to the main body portion and arranged inside the main body portion in the tire width direction and displaced in the tire circumferential direction, and The number of pitches of the large blocks in the tire circumferential direction is one third or less of the number of pitches of the blocks, and the small blocks are arranged between the respective extension portions continuous in the tire circumferential direction.

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

The pneumatic tire of the present invention is mounted on a vehicle such that the tread on one side is located outside the vehicle and the tread on the other side is located inside the vehicle.

According to the pneumatic tire of the present invention, since the difference between the negative rate of the tread on one side and the negative rate of the tread on the other side is 5% or less, the actual ground contact area of the tread on one side and the actual tread of the tread on the other side are Almost no difference from the contact area. As a result, the difference in wear between the tread on one side and the tread on the other side can be minimized.

The "negative rate" is a value obtained by multiplying the value obtained by dividing the groove area by the total ground contact area (including the groove area) of the tire by 100.

Further, since the circumferential continuous center rib is arranged offset to one side in the tire width direction with respect to the tire equator line, it is possible to prevent buckling at the center of the tread during cornering as much as possible.

That is, taking a left wheel tire as an example, when the handle is turned to the right, a relatively large load (centrifugal force) acts from the tire equator line of the tire to the tread on one side. For this reason, a large load is applied to the vehicle outer side portion of the circumferentially continuous center rib, bending deformation becomes large, and the ground contact length becomes long. However, in the present invention, since the circumferential continuous center rib is arranged offset to one side in the tire width direction with reference to the tire equator line, the circumferential continuous center rib is located outside the vehicle with respect to the tire equator line. The outer volume of the vehicle is increased, and the rigidity is increased accordingly. When the rigidity of the vehicle outer side portion of the circumferential center rib is increased, the bending deformation of the vehicle outer side portion is suppressed even if a large load is applied, and the ground contact length does not become so long. As a result, the difference in the partial contact length of the circumferential continuous center rib is reduced, and it is possible to prevent the occurrence of the buckling phenomenon that a part (central portion) of the circumferential continuous central rib rises during cornering as much as possible. It is possible to prevent deterioration of steering stability.

In particular, the rib width of the circumferential continuous center rib is 5% or more and 20% or less of the tread width of all treads, and the offset amount of the center line of the circumferential continuous central rib from the tire equator line is less than the rib width. By doing so, it is possible to more effectively prevent the occurrence of buckling.

Further, the other tread has a plurality of lateral grooves formed at intervals in the tire circumferential direction and extending toward the tire width direction outer end, and the number of blocks formed by the lateral grooves is 40. Since it is more than 60 and less than W, W
Drainability on the ET road surface can be improved.

Particularly, since the number of blocks is less than 60 and the lateral grooves are not excessively provided, the pattern rigidity is not excessively lowered. On the contrary, if the number of block pitches is less than 40, drainage cannot be ensured, which is inappropriate.

On the other hand, since the one side tread has a block row composed of large blocks and small blocks, the pattern rigidity of the one side tread can be improved,
The steering stability can be improved.

Here, assuming that the large block has a simple shape of, for example, a substantially quadrangular shape and the number of pitches in the tire circumferential direction is one third or less of the number of pitches of the lateral grooves, the pattern rigidity of the tread on one side is further improved. Although it is possible, the number of grooves communicating with the tire width direction end of the one side tread is insufficient,
There is a problem that drainage performance deteriorates.

Therefore, as in the present invention, the number of pitches in the tire circumferential direction of the large block is set to one third or less of the number of pitches of the block. However, by configuring the large block with the main body and the extension, Since it is possible to secure a certain number of grooves that communicate with the tire width direction end of the one-side tread, it is possible to prevent deterioration of drainage. At the same time, since a large block that is long in the tire circumferential direction can be arranged, pattern rigidity can be improved and steering stability can be improved. That is, in the tread on one side, it is possible to secure the pattern rigidity and prevent deterioration of drainage.

Further, since the large block is composed of the main body portion and the extension portion, the main body portion and the extension portion can move independently to some extent while ensuring the block rigidity of the large block as a whole. Can be flexible. As a result, it is possible to prevent the pattern rigidity of the tread on one side from becoming too high, and it is possible to prevent the wear difference from increasing due to the difference in pattern rigidity between the tread on the one side and the tread on the other side.

The pneumatic tire is used by being attached to a rim defined by a standard issued by JATMA (Japan) or the like according to each size, and this rim is usually called a regular rim.

Similarly, "normal load" and "normal internal pressure" mean
The maximum load and the air pressure for the maximum load in the applicable size and ply rating specified in the standard.

In the present specification, the "tread width" means the tread portion when the tire is assembled to the "regular rim", the "regular internal pressure" is filled, and the "regular load" is statically applied. Indicates the maximum ground contact width in the tire width direction (tire axial direction).

Here, the load is the maximum load (maximum load capacity) of a single wheel in the applicable size described in the following standard.
The internal pressure is the air pressure that corresponds to the maximum load (maximum load capacity) of a single wheel in the applicable size listed in the standards below, and the rim is the applicable size listed in the standards below. It is a standard rim.

The standard is defined by an industrial standard effective in the region where the tire is produced or used. For example, in Japan, "JATMA" of the Japan Automobile Tire Manufacturers Association
"Year Book".

In the pneumatic tire according to claim 2, a pair of circumferential grooves that are continuous in the tire circumferential direction and that define the circumferential continuous center rib are formed on both sides of the circumferential continuous center rib in the tire width direction. The other side tread has the above 1
Of the pair of circumferential grooves, the other circumferential groove located on the other side tread and the end circumferential groove located outside the other circumferential groove in the tire width direction and continuous with the circumferential direction of the tire and the other circumferential groove. One side circumferential direction that has an intermediate block row defined by a side circumferential groove and a communication groove that communicates the end side circumferential groove, and is located on the one side tread of the pair of circumferential grooves. The groove width of the groove is formed wider than the groove width of the other side circumferential groove, and the one side tread has a circumferential groove continuous in the tire circumferential direction in addition to the one side circumferential groove. Characterized by not being.

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

Since the tread on the other side has the intermediate block row, the pattern rigidity of the tread on the other side becomes high, and it is possible to prevent uneven wear due to a decrease in the pattern rigidity of the tread on the other side.

On the other hand, in the one side tread, the groove width of the one side circumferential groove is formed wider than the groove width of the other side circumferential groove,
Moreover, since there is no circumferential groove continuous in the tire circumferential direction other than the one-side circumferential groove, it is possible to prevent the drainage of the one-side tread from decreasing and the pattern rigidity from decreasing.

In the pneumatic tire according to claim 3, a circumferential direction continuous end side rib continuous in the tire circumferential direction is formed on the tire width direction outer side of the end side circumferential groove of the other side tread, It is characterized in that the lateral groove is blocked by the circumferentially continuous end side rib and does not communicate with the other circumferential groove.

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

Since the ribs on the other side are continuously formed in the circumferential direction, the pattern rigidity of the other side tread can be further improved, and uneven wear due to a decrease in the pattern rigidity of the other side tread can be prevented. be able to.

At the same time, the rib in the circumferential direction continuous end portion prevents the lateral groove from communicating with the circumferential groove in the other side, so that the pattern rigidity due to the lateral groove communicating with the circumferential groove in the other side is significantly increased. You can prevent the decline. As a result, due to the synergistic effect, the uneven wear of the other tread can be prevented more effectively.

A pneumatic tire mounting method according to claim 4 is the pneumatic tire mounting method according to any one of claims 1 to 3, wherein the one-side tread is located outside the vehicle. The pneumatic tire is mounted on the vehicle so that the other tread is located inside the vehicle.

Next, the operation and effect of the pneumatic tire mounting method according to the fourth aspect will be described.

By mounting the pneumatic tire according to any one of claims 1 to 3 on a vehicle so that the tread on one side is located outside the vehicle and the tread on the other side is located inside the vehicle. In addition to achieving both steering stability and WET performance, it is possible to minimize the difference in wear between the tread on one side and the tread on the other side with respect to the tire equator line.

[0040]

BEST MODE FOR CARRYING OUT THE INVENTION A pneumatic tire according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, in the tread 12 of the pneumatic tire 10 of the present invention, the outer tread OT located outside the vehicle (on the side of the arrow C in FIG. 1) when the vehicle is mounted on the basis of the tire equator line CL. (One side tread)
And an inner tread IT (the other side tread) located inside the vehicle (on the side of the arrow D in FIG. 1) when the vehicle is mounted on the basis of the tire equator line CL.

In the pneumatic tire 10 of the present invention, the outer tread OT and the inner tread IT have different pattern configurations, and have a bilaterally asymmetric tread pattern TP.

When the pneumatic tire 10 shown in FIG. 1 is viewed as a tire for the left wheel, the arrow A indicates that the vehicle is moving forward.
Shall rotate in the direction. Hereinafter, description will be made based on this criterion.

In the tread 12 of the pneumatic tire 10,
A circumferential continuous center rib 14 is formed. The circumferential continuous center rib 14 is formed to be offset to the vehicle outer side (the arrow C direction side in FIG. 1) when the vehicle is mounted with the tire equator line CL as a reference.

The rib width of the circumferential continuous center rib 14 measured in the tire width direction (direction C or D in FIG. 1) is 5% or more of the tread width W of the tread 12 20.
It is set to% or less.

Among them, the rib width is tread 12
It is particularly preferable that the width is set to about 10% of the tread width W.

Further, the center line l of the circumferentially continuous center rib 14
The offset amount OF from the tire equator line CL is set to be less than the rib width.

The inner tread IT is an inner circumferential groove 16 (the other circumferential groove) extending continuously in the tire circumferential direction on the vehicle inner side of the circumferential continuous center rib 14 (on the side of the arrow D in FIG. 1). ) Has been formed.

Further, an end side circumferential groove 18 extending continuously in the tire circumferential direction is formed inside the vehicle at a predetermined distance from the inner circumferential groove 16.

Further, a connecting groove 20 which connects the inner circumferential groove 16 and the end-side circumferential groove 18 is formed.

As described above, in the inner tread IT, the intermediate blocks 22 defined by the inner circumferential groove 16, the end side circumferential groove 18, and the connecting groove 20 are arranged in the tire circumferential direction, and the intermediate block row is formed. Is formed.

Further, on the vehicle inner side (outer side in the tire width direction) of the end side circumferential groove 18, a circumferential direction continuous end side rib 24 continuous in the tire circumferential direction is formed.

Further, a circumferential narrow groove 26 continuously extending in the tire circumferential direction is formed inside the vehicle (outer side in the tire width direction) of the circumferentially continuous end side rib 24.

Further, from the circumferential narrow groove 26 to the inner tread I
A plurality of widthwise lateral grooves 28 (lateral grooves) are formed at predetermined intervals in the tire circumferential direction toward the tire width direction outer end side (shoulder end side) of T. This transverse groove 2
The number of pitches of 8 (or the end side block 30 described later) is
It is set to 40 or more and less than 60.

As described above, the widthwise lateral groove 28 is blocked by the circumferentially continuous end portion side rib 24 and does not communicate with the inner circumferential groove 16 and the end portion side circumferential groove 18.

A plurality of end side blocks 30 defined by the circumferential narrow groove 26 and the widthwise lateral groove 28 are formed in the tire circumferential direction.

On the other hand, on the outer tread OT and on the vehicle outer side of the circumferentially continuous center rib 14 (on the arrow C side in FIG. 1), the outer circumferential groove 32 extending continuously in the tire circumferential direction.
(One side circumferential groove) is formed.

The groove width of the outer circumferential groove 32 is wider than the groove width of the inner circumferential groove 16 and the end side circumferential groove 18.

On the vehicle outer side of the outer circumferential groove 32 (outer side in the tire width direction), a plurality of large blocks 34 are formed along the tire circumferential direction. The number of pitches of the large blocks 34 in the tire circumferential direction is set to one third or less of the number of pitches of the widthwise lateral grooves 28 (or the end block 30).

The large block 34 has a substantially quadrangular main body portion 36 located on the outer end side in the tire width direction, and the main body portion 3.
6 and a substantially quadrangular extension portion 38 that is formed on the inner side in the tire width direction and is displaced in the tire circumferential direction. The main body portion 36 and the extension portion 38 are connected by a connection portion 40 having a relatively narrow width.

As described above, a plurality of large blocks 34 are formed along the tire circumferential direction, but the extension portion 38 of each large block 34 is a main body portion of another large block 34 adjacent to the large block 34. It is located inside the tire width direction of 36.

Further, small blocks 42 each having a quadrangular shape are formed between the extension portions 38 of each large block 34.

Further, the kicking edge R of the small block 42
A first central inclined groove 44 that is inclined with respect to the tire width direction is formed between E and the depression edge FE of the extension portion 38 of the large block 34.

The stepping edge FE of the small block 42
The second central inclined groove that is inclined with respect to the tire width direction is provided between the kicking edge RE of the extension portion 38 of the other large block 34 that is adjacent to the tire rotation direction (arrow A direction in FIG. 1). 46 is formed.

Further, in the main body portion 36 of the large block 34,
A first end sloped groove 48 is formed at a position on the extension line of the second central sloped groove 46.

Further, a first central vertical groove 50 is formed between the tire width direction outer edge OE of the small block 42 and the tire width direction inner edge IE of the body portion 36 of the large block 34. .

Further, the tire width direction outer end edge OE of the extension portion 38 of the other large block 34 and the tire width direction inner end edge IE of the large block 34 which are adjacent to each other in the tire rotation direction (the direction of arrow A in FIG. 1). A second central vertical groove 52 is formed therebetween.

Further, between the stepping edge FE of the main body 36 of the large block 34 and the kicking edge RE of the other main body 36 of the large block 34 adjacent in the tire circumferential direction, a second
End groove 54 is formed.

The outer tread OT has no circumferential groove continuous in the tire circumferential direction other than the outer circumferential groove 32 described above.

The outer tread OT and the inner tread I
The difference from the negative rate of T is set to 5% or less.
As described above, the outer tread OT is not formed with the intermediate block 22, the circumferentially continuous end side ribs 24, and the end side blocks 30 like the inner tread IT, but is a small block in addition to the large block 34. Since 42 is formed, the difference in negative ratio between the outer tread OT and the inner tread IT can be set within 5%.

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

First, in the pneumatic tire 10 of the present invention, the outer tread OT is located outside the vehicle, and the inner tread IT is
Is mounted on the vehicle such that the vehicle is located inside the vehicle.

According to the pneumatic tire 10 of the present invention, since the difference between the negative rate of the outer tread OT and the negative rate of the inner tread IT is 5% or less, the actual ground contact area of the outer tread OT and the inner tread IT of the inner tread IT. Almost no difference from the actual contact area. As a result, the difference in wear caused by the difference in the actual ground contact area between the outer tread OT and the inner tread IT can be minimized.

Further, since the circumferential continuous center ribs 14 are arranged offset to the outside of the vehicle with respect to the tire equator line CL, it is possible to prevent buckling at the center of the tread during cornering as much as possible.

That is, taking the left wheel tire as an example, if the handle is turned to the right, a relatively large load (centrifugal force) is exerted from the tire equatorial line CL of the tire 10 to the outer tread OT.
Works. Therefore, the vehicle outer side portion of the circumferentially continuous center rib 14 receives a large load, the bending deformation becomes large, and the ground contact length becomes long. However, in the present invention, since the circumferential continuous center rib 14 is arranged offset to the vehicle outer side with respect to the tire equator line CL, the circumferential continuous center rib 14 is placed outside the vehicle with respect to the tire equator line CL as a reference. The volume of the vehicle outside portion located is increased, and the rigidity is increased accordingly. If the rigidity of the vehicle outer side portion of the circumferential continuous center rib 14 is increased, the bending deformation of the vehicle outer side portion is suppressed even if a large load is applied, and the ground contact length does not become so long. As a result, the partial difference in the contact length between the circumferential continuous center ribs 14 becomes small, and it is possible to prevent the occurrence of a buckling phenomenon in which a part (central portion) of the circumferential continuous center ribs 14 is lifted during cornering. It is possible to prevent a decrease in steering stability during operation.

In particular, the rib width of the circumferential center rib 14 is set to 5% or more and 20% or less of the tread width W of all the treads 12, and the center line 1 of the circumferential center rib 14 is offset from the tire equator line CL. By setting the amount to be less than the rib width, it is possible to more effectively prevent the occurrence of the buckling.

Further, since the inner tread IT has a plurality of lateral grooves 28 in the width direction and the number of pitches of the end side blocks 30 is 40 or more and less than 60, the drainage property on the WET road surface should be improved. You can In particular, since the number of pitches of the widthwise lateral grooves 28 in the tire circumferential direction is less than 60 and the widthwise lateral grooves 28 are not excessively provided, the pattern rigidity does not excessively decrease. On the contrary, when the number of pitches of the widthwise lateral grooves 28 in the tire circumferential direction is less than 40, drainage cannot be secured, which is inappropriate.

On the other hand, since the outer tread OT has the block row composed of the large blocks 34 and the small blocks 42, the pattern rigidity of the outer tread OT can be improved and the steering stability can be improved. You can

Here, assuming that the large block 34 has a simple shape of, for example, a substantially quadrangle, and the number of pitches in the tire circumferential direction is one third or less of the number of pitches of the end side block 30, the outer tread OT is formed. Although the pattern rigidity can be further improved, there is a problem that the number of grooves communicating with the end portion of the outer tread OT in the tire width direction is insufficient and drainage performance deteriorates.

Therefore, as in the present invention, the large block 34
Is composed of a main body portion 36 and an extension portion 38, and the number of pitches of the large blocks 34 in the tire circumferential direction is set to the end portion side block 3
By setting the pitch number of 0 to 1/3 or less, the first
Central inclined groove 44, second central inclined groove 46, first central longitudinal groove 50, second central longitudinal groove 52 and second end inclined groove 5 of
Since the number of grooves communicating with the tire width direction end portion of the outer tread OT can be secured to some extent by 4, the deterioration of drainage can be prevented. At the same time, since the large block 34 that is long in the tire circumferential direction can be arranged, the pattern rigidity is improved and the steering stability can be improved. That is,
In the outer tread OT, pattern rigidity can be ensured and deterioration of drainage can be prevented.

Further, since the large block 34 is composed of the main body portion 36 and the extension portion 38 and the width of the connecting portion 40 is narrow, the main body portion 36 and the extension portion 38 are secured while ensuring the block rigidity of the large block 34 as a whole. It becomes possible to move to a certain extent independently of each other, and the large block 34 can be made flexible. As a result, it is possible to prevent the pattern rigidity of the outer tread OT from becoming too high, and it is possible to prevent the wear difference from increasing due to the difference in pattern rigidity between the outer tread OT and the inner tread IT.

Further, the main body 36 of the large block 34 and the extension 38, the main body 36 of the large block 34 and the small block 4
The widths of the first central vertical groove 50 and the second central vertical groove 52 that demarcate 2 are narrowed to such an extent that the first central vertical groove 50 and the second central vertical groove 52 disappear when touching the road surface. If so, an effect as an extra large block in which the large block 34 and the small block 42 are combined can be expected.

(Test Example) Next, regarding the pneumatic tire of the present invention (Example), the conventional pneumatic tire (Conventional example) and the comparative tires (Comparative Example 1 and Comparative Example 2), dry steering stability, WET A test was conducted to test the drainage property and the abrasion property.

All tire sizes are 235 / 45ZR
It was set to 17.

As a test method, dry steering stability was determined by running a circuit course on a vehicle equipped with each of the test tires and measuring the circuit running time. Therefore, the smaller the value of dry steering stability in Table 2 below, the better the result.

The WET drainage property was measured by running a vehicle equipped with each of the above test tires on a road surface having a water depth of 2 mm and measuring the rate of hydroplaning generation. Therefore, the larger the value of WET drainage in Table 2 below, the better the result.

Regarding the wear resistance, an actual running wear test was conducted on a vehicle equipped with each of the above test tires, and the wear amount of the outer tread and the wear amount of the inner tread were compared. Therefore, the more the abrasion resistance values in Table 2 below are the same, the better the results are.

The test conditions for each tire are shown in Table 1 below.

[0089]

[Table 1]

Here, the term "Example" in Table 1 above refers to FIG.
It is a pneumatic tire having a tread pattern shown in.

"Comparative example 1" is a pneumatic tire having a tread pattern shown in FIG. That is, as shown in FIG. 2, in Comparative Example 1, although the blocks of the outer tread OT are not divided into large blocks and small blocks, a single oversized block 100 is formed based on the embodiment, and this oversized block 100 is used. A plurality of tires are arranged in the tire circumferential direction. The other conditions of Comparative Example 1 are set in the same manner as in Example.

"Comparative example 2" is a pneumatic tire having a tread pattern shown in FIG.

That is, as shown in FIG.
In the inner tread IN, there is no circumferential direction continuous end side rib as in the embodiment, and a plurality of blocks 200 are arranged in the tire circumferential direction. Further, in the outer tread OT, the relatively large end block 20 is provided on the shoulder end side.
2 are arranged in the tire circumferential direction, and a relatively small central block 204 is provided inside the end block 202 in the tire width direction.
Are arranged in the tire circumferential direction.

The "conventional example" is a pneumatic tire having the tread pattern shown in FIG.

That is, as shown in FIG.
It has a bilaterally symmetrical tread pattern, and is provided with a tread pattern having a configuration greatly different from that of the embodiment.

A central circumferential groove 302 extending in the tire circumferential direction is formed near the tire equator line CL, and the central circumferential groove 3 is formed.
On the outer side in the tire width direction of No. 02, circumferential continuous ribs 304 continuous in the tire circumferential direction are formed, respectively. A pair of circumferential grooves 306 extending in the tire circumferential direction are formed on the outer sides of the circumferential continuous ribs 304 in the tire width direction. An intermediate block 30 is provided outside each circumferential groove 306 in the tire width direction.
A plurality of 8 are arranged in the tire circumferential direction. An end side circumferential groove 310 extending in the tire circumferential direction is formed on the tire width direction outer side of the intermediate block 308. A plurality of end blocks 312 are arranged in the tire circumferential direction outside the end side circumferential groove 310 in the tire width direction.

The results of this test are shown in Table 2 below.

[0098]

[Table 2]

As shown in Table 2 above, in the examples of the pneumatic tire of the present invention, the dry steering stability and the WET drainage are equal to or more than those of Comparative Examples 1, 2 and the conventional example. It was

Particularly, regarding the WET drainage property, Comparative Example 1
It is significantly improved as compared with, while the block arrangement of the outer tread OT of the embodiment maintains the dry steering stability,
It was found to bring about a large drainage effect.

On the other hand, with respect to the wear resistance, it was found that the left tread and the right tread were uniform in the examples, and there was no difference in wear. On the other hand, Comparative Example 1 has a difference in wear, and it was found that the block row of the outer tread of the example helps prevent the difference in wear.

As described above, in the pneumatic tire of the present invention, both dry steering stability and WET performance can be achieved, and the difference in wear between the outer tread and the inner tread can be minimized or eliminated. it can.

[0103]

According to the present invention, both steering stability and WET performance can be achieved, and the difference in wear between the outer tread and the inner tread with respect to the tire equator line can be minimized.

[Brief description of drawings]

FIG. 1 is a diagram showing a tread pattern of a pneumatic tire according to an embodiment of the present invention.

FIG. 2 is a diagram showing a tread pattern of a pneumatic tire of Comparative Example 1.

FIG. 3 is a diagram showing a tread pattern of a pneumatic tire of Comparative Example 2.

FIG. 4 is a view showing a tread pattern of a conventional pneumatic tire.

[Explanation of symbols]

10 pneumatic tires 14 Circumferential continuous center rib 16 Inner circumferential groove (other circumferential groove) 18 Edge side circumferential groove 20 connecting groove 24 Circumferentially continuous end side rib 28 Width lateral groove (horizontal groove) 30 End block (block) 32 outer circumferential groove (one side circumferential groove) 34 large blocks 36 Body 38 Extension 42 small blocks

Claims (4)

[Claims] 1. A pneumatic tire having a tread pattern that is bilaterally asymmetric with respect to the tire equator line, wherein the negative ratio and the tire equator line of one side tread located on one side in the tire width direction with respect to the tire equator line As a reference, the difference from the negative rate of the other tread located on the other side in the tire width direction is 5% or less, and the rib width is 5% or more and 20% or less of the tread width of all treads, and the tire equatorial line is used as a reference. As arranged on the one side in the tire width direction as an offset, and having a circumferential continuous center rib continuous in the tire circumferential direction in which the offset amount from the tire equator of the center line is less than the rib width, on the other side tread. The block having a plurality of lateral grooves formed at intervals in the tire circumferential direction and extending toward the tire width direction outer end, and formed by the lateral grooves. The number of pitches is 40 or more and less than 60, the one side tread has a block row composed of a large block and a small block, the large block, the main body portion arranged on the tire width direction outer side, It is composed of an extension portion that is connected to the main body portion and is arranged inside the tire width direction with respect to the main body portion and is displaced in the tire circumferential direction, and the number of pitches in the tire circumferential direction of the large block is equal to that of the block. The pneumatic tire is one third or less of the number of pitches, and the small blocks are arranged between the extension portions that are continuous in the tire circumferential direction. 2. A pair of circumferential grooves that are continuous in the tire circumferential direction and that partition the circumferential continuous center rib are formed on both sides of the circumferential continuous center rib in the tire width direction, and the other tread is formed on the other side tread. Of the pair of circumferential grooves, the other circumferential groove located on the other tread, and the end circumferential groove located outside the other circumferential groove in the tire width direction and continuous in the tire circumferential direction. An intermediate block row that is defined by a communication groove that communicates the other side circumferential groove and the end side circumferential groove, and one side of the pair of circumferential grooves that is located on the one side tread. The groove width of the circumferential groove is formed wider than the groove width of the other side circumferential groove, and the one side tread has a circumferential groove continuous in the tire circumferential direction in addition to the one side circumferential groove. The pneumatic filter according to claim 1, which is not Ya. 3. A circumferential direction continuous end side rib that is continuous in the tire circumferential direction is formed outside the end side circumferential groove of the other side tread in the tire width direction, and the lateral groove is the circumferential continuous end. The pneumatic tire according to claim 2, wherein the pneumatic tire is blocked by the part-side rib and does not communicate with the other-side circumferential groove. 4. The method for mounting a pneumatic tire according to claim 1, wherein the one side tread is located outside the vehicle and the other side tread is located inside the vehicle. A method of mounting a pneumatic tire, characterized in that the pneumatic tire is mounted on the vehicle.