JP2003211920A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of improving performance on ice and block rigidity. <P>SOLUTION: In a shoulder block 20, a plurality of tire widthwise sipe rows 32 comprising first zigzag sipes 32A ending near a block center and second zigzag sipes 32B arranged with intervals to the first zigzag sipes 32A are formed in a tire circumferential direction. Pseudo-circumferential sipes 35 extending in a tire circumferential direction are formed by short pieces 33E of the first zigzag sipes 32A and short pieces 34E of the second zigzag sipes 32B. Since the pseudo-circumferential sipes 35 extending in the tire circumferential direction are arranged in a block center, a water film of a block center area is quickly taken in the sipes during traveling on ice, and braking performance on ice can be improved. Since the tire widthwise sipe rows 32 are parted once at intermediate portions, rigidity of the shoulder block 20 is secured. <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 having a plurality of blocks on a tread, and in particular, it is possible to improve ice performance and block rigidity of a winter pneumatic tire. Regarding pneumatic tires.

[0002]

2. Description of the Related Art As a conventionally known siping of a tire capable of exerting a well-balanced performance on ice and snow, as shown in FIG. 5, a block (20, 22, 26) has a wavy sipes (32, 36, 38). , 40) are generally arranged at substantially uniform intervals.

[0003]

However, in the conventional sipe, since a long sipe is arranged in the block substantially parallel to the tire axial direction, if the sipe interval is narrow, the block rigidity tends to be insufficient, and the brake, Also, there is a problem that the block easily falls during traction.

Further, in the conventional siping, since only the sipes which are substantially parallel to the tire axial direction are formed, the tire circumferential direction edge component effective during cornering is insufficient.

Further, in the conventional siping, it was difficult to remove the water film near the center of the block when traveling on ice.

In view of the above facts, an object of the present invention is to provide a pneumatic tire capable of improving the performance on ice and the block rigidity.

[0007]

According to a first aspect of the present invention, a tread is provided with a plurality of blocks defined by a plurality of grooves intersecting with each other, and the blocks have a wavy shape extending in the tire width direction. A pneumatic tire having a plurality of zigzag sipes formed in the tire circumferential direction and at least one wavy zigzag sipes extending along the tire circumferential direction, wherein the blocks are in mutually opposite directions. A plurality of zigzag-shaped sipes, which are zigzag-shaped by alternately connecting short pieces that are inclined to each other, are arranged in a substantially linear shape in the tire circumferential direction without being connected to each other in the tire width direction. In the plurality of tire width direction sipe rows, the short piece including one end portion adjacent to each other is more than twice the short piece including the end portion of the other zigzag sipe. It is has, disposed near the center of the shorter the short side the short piece end portions of the longer of, and,
The end portion of the longer short piece is arranged near the end portion on the opposite side of the end portion side of the shorter piece of the other zigzag sipe that is adjacent to the tire circumferential direction, whereby the tire width direction of the block is obtained. One or more pseudo circumferential sipes extending substantially in the zigzag shape in the tire circumferential direction are formed near the central portion.

Next, the operation of the pneumatic tire according to claim 1 will be described.

By forming a plurality of blocks by arranging a plurality of grooves intersecting with each other on the tread and forming zigzag sipes extending in the tire width direction on the blocks, the running performance on ice and snow is basically achieved. The required pattern configuration is obtained.

Since a pseudo circumferential sipe extending in the tire circumferential direction is arranged near the center of the block in the tire width direction, the water film in the central region of the block is swiftly taken into the sipe when traveling on ice, and the braking performance on ice is improved. And the traction performance can be improved.

In a plurality of tire width direction sipe rows, a short piece including one end portion adjacent to each other has a length that is at least twice as long as a short piece including the end portion of the other zigzag sipe. The edge component in the tire circumferential direction is increased, and the cornering performance when traveling on ice is improved.

Further, since the sipe row in the tire width direction is divided once at the intermediate portion (that is, it is formed by a plurality of zigzag sipe which are not connected to each other).
Compared to the case of using a conventional sipe that continuously crosses the tire width direction of the block, the rigidity of the block is higher and it is possible to suppress the collapse of the block when a force is applied in the front-back direction such as traction and braking. , On ice, on snow,
It improves braking and traction performance on all wet and dry road surfaces, and also improves maneuverability.

In addition, in a plurality of tire width direction sipe rows, a short piece including one end portion adjacent to each other is set to have a length that is at least twice as long as a short piece including the end portion of the other zigzag sipe. That is, if one of the short pieces is not set to be long in this way, the distance between the sipe rows in the tire width direction becomes narrow when the end portion of the longer piece is arranged near the adjacent short piece in the tire circumferential direction. This is because the block rigidity is reduced and the steering stability is deteriorated.

According to a second aspect of the invention, in the pneumatic tire according to the first aspect, the distance between the terminal end portion and the short piece of the other zigzag sipe closest to the terminal end portion is It is characterized in that it is in the range of 0.1 to 1.0 mm.

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

When the distance between the end portion and the short piece of the other zigzag sipe closest to this end portion becomes less than 0.1 mm, the sipe and the sipe are immediately connected when the tire is mounted on the vehicle and the vehicle is run ( The rubber between the sipes will break),
As a result, sipes are connected both in the tire width direction and the tire circumferential direction, so that the block rigidity is decreased, which may lead to deterioration of dry performance and the like.

If the distance between the end portion and the other short piece of the zigzag sipe closest to the end portion exceeds 1.0 mm, the block rigidity becomes too high and the sipe length becomes too short. This may adversely affect the snow running performance. It should be noted that since the sipes are not connected even when the vehicle runs, the phenomenon that the block rigidity is too high occurs even during wear.

The distance between the end portion and the other short piece of the zigzag sipe closest to the end portion is 0.3.
The range of 0.5 mm is more preferable.

With such a setting, when the groove depth of the sipes is new, the sipes are not connected to each other, the rigidity of the block is maintained, the groove depth of the sipes is reduced due to wear, and the rigidity of the block itself is reduced. As the groove depth of the sipe becomes higher than 70% of that of a new product, the rubber between the sipes will be broken and the block will have an appropriate rigidity, and even if the groove depth of the sipe remains, Since it is easy to open, it can maintain the same performance as a new product for a long time.

According to a third aspect of the present invention, in the pneumatic tire according to the first or second aspect, three or more tire width direction sipe rows are formed in the block, and the pseudo circumferential direction sipe is formed. It is characterized in that one is formed.

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

Winter tires (so-called studless tires)
First, high ice performance and snow performance (brake performance and traction performance) are required.

By providing three or more sipe rows in the tire width direction in one block, the high on-ice performance (brake performance and traction performance) required for a winter tire can be reliably obtained.

Further, as a tire, of course, a performance on a dry road surface is also required, and in order to maintain the block rigidity and generate a lateral force necessary for cornering etc., it is preferable to have one pseudo circumferential sipe. .

The invention according to claim 4 is the pneumatic tire according to any one of claims 1 to 3.
The plurality of zigzag sipes in the tire width direction sipe row are formed from straight short pieces, have substantially the same amplitude and the same wavelength, and are arranged on the same straight line, and the angle with respect to the tire circumferential direction is measured clockwise. It is characterized in that it is in the range of 60 to 120 degrees.

Next, the operation of the pneumatic tire according to claim 4 will be described.

If the angles of the plurality of zigzag sipes arranged on the same straight line with respect to the tire circumferential direction deviate from the above range, the plurality of zigzag sipes may not work effectively in the front-rear direction (traction and braking). There is.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view showing a tread 12 of a pneumatic tire 10 according to an embodiment of the present invention.

In FIG. 1, reference numeral 12C is a tread 12.
Is a central region of the tread when the tire is divided into three parts in the tire width direction, and reference numeral 12S is a tread side region.
In addition, reference numeral ½W ₀ in FIG. 1 indicates the ground contact width on one side of the tread, arrows A and B indicate the circumferential direction, and arrow C indicates the tire width direction.

The definition of the tread central area 12C is as follows.

In the present invention, the pneumatic tire is mounted on a standard rim described below, is filled with standard air pressure, and is subjected to a standard load. One of the outermost ends in the tire width direction (tread end) in the tire width direction. ) To the other outermost end (tread end) in the tire width direction is divided into three equal parts, and the central region is defined as the central region.

The standard rim is a rim defined by the JATMA (Japan Automobile Tire Manufacturers Association) Year Book 2001 edition, and the standard air pressure is the air pressure corresponding to the maximum load capacity of the JATMA (Japan Automobile Tire Manufacturers Association) 2001 edition. Yes, standard load is JATM
Year Book 20 from A (Japan Automobile Tire Manufacturers Association)
This is the load equivalent to the maximum load capacity when applying the 2001 single wheel.

In addition to Japan, the load is the maximum load (maximum load capacity) of a single wheel in the applicable size described in the following standard, and the air pressure is the single wheel specified in the following standard. It is the air pressure corresponding to the maximum load (maximum load capacity), and the rim is the standard rim (or "ApprovedRi" in the applicable size described in the following standards).
m "," Recommended Rim ").

The standard is determined by an industrial standard that is effective in the region where the tire is produced or used. For example, in the United States, “The Tire and Rim Association I
nc.'s Year Book ”and in Europe it is“ The European Ti
Standards Manua from re and Rim Technical Organization
l ”.

As shown in FIG. 1, in the tread central region 12C of the tread 12, there is a first linear extension along the tire circumferential direction on both sides of the tire equatorial plane CL.
A circumferential main groove 14 is formed.

Further, a second circumferential main groove 16 extending linearly along the tire circumferential direction is formed on the tread 12 outside the first circumferential main groove 14 in the tire width direction.

The second circumferential main groove 16 of this embodiment is formed near the 1/4 point of the tread 12.

The tread 12 has an opening at the ground contact end 12E of the tread 12, and the second circumferential main groove 1 extends from the ground contact end 12E.
Crossing main grooves 18 that extend across 6 and extend toward the first circumferential main groove 14 are formed at substantially equal intervals in the tire circumferential direction.

Therefore, a plurality of shoulder blocks 20 defined by the second circumferential main groove 16 and the transverse main groove 18 are provided on the shoulder side of the tread 12, and on the tire equatorial plane CL of the tread 12. The center rib 22 extending along the tire circumferential direction is provided.

The transverse main groove 18 terminates in the vicinity of the first circumferential main groove 14.

The transverse main groove 18 is inclined so that the angle with respect to the tire width direction gradually increases toward the tire equatorial plane CL side, and the inclination directions are opposite on the right side and the left side across the tire equatorial plane CL. Is set to.

A sub-groove 24 having a narrower groove width than the transverse main groove 18 is connected to an end of the transverse main groove 18 on the side of the first circumferential main groove 14.

The sub-groove 24 extends from the end portion on the side of the first circumferential main groove 14 toward the outer side in the tire width direction while inclining in the same direction with respect to the tire circumferential direction and adjacent to the transverse main groove 1.
It ends in the vicinity of 8.

The angle of the auxiliary groove 24 with respect to the tire circumferential direction is
It is set relatively small.

As shown in FIG. 2, the auxiliary groove 24 and the transverse main groove 1
The angle (average value) θ formed by 8 is preferably set to 45 ° or more.

Thereafter, in the present embodiment, in the land portion 26 between the first circumferential main groove 14 and the second circumferential main groove 16, the first circumferential main groove 14 and the sub groove 24 are separated from each other. The space between the rib-shaped portion 26A and the sub groove 24 and the second circumferential main groove 16 is called a block-shaped portion 26B.

The average width W ₁ of the rib portion 26A is
Is preferably in the range of 5 to 30% of the one-side ground contact width 1/2 W ₀ .

The end portion of the transverse main groove 18 on the first circumferential main groove 14 side and the first circumferential main groove 14 are narrow grooves 28 having a narrower groove width than the first circumferential main groove 14. Are connected by.

As shown in FIG. 1, the center rib 22 has an auxiliary groove 30 whose groove width is narrower than that of the first circumferential main groove 14.
Are formed in the tire circumferential direction to form a block row.

In this embodiment, all the auxiliary grooves 30 are inclined in the same direction. (Sipe of Shoulder Block) FIG. 3 shows an enlarged tread surface of the shoulder block 20 on the right side of the tire equatorial plane CL.

As shown in FIG. 3, the shoulder block 2
0 is made into a zigzag shape by alternately connecting short pieces 33 that are inclined in opposite directions, and is on the tire equatorial plane CL side (see FIG. 3).
Shoulder block 20 from the edge of the arrow IN side)
Of the first zigzag sipe 32A extending toward the center of the shoulder width direction of the shoulder block 20 and terminating near the center of the shoulder block 20 in the tire width direction.
A short piece 34 is arranged on the extension line of A so as to form a pair with the first zigzag sipe 32A and is inclined in opposite directions.
Are alternately connected to form a zigzag shape, extend from the end edge on the shoulder side (arrow OUT side in FIG. 3) to the tire width direction center of the shoulder block 20, and terminate near the tire width direction center of the shoulder block 20. A plurality of second zigzag sipes 32B and a tire width direction sipe row 32 are formed in the tire circumferential direction.

Here, the short piece 33E including the terminal end portion on the block center side of the first zigzag sipe 32A has a length approximately twice that of the other short pieces 33.

The end of the short piece 34E on the block center side of the second zigzag sipe 32B is arranged near the center of the long piece 33E of the first zigzag sipe 32A.

Further, the end portion of the long short piece 33E of the first zigzag sipe 32A has a second end adjacent to the tire circumferential direction.
The zigzag sipe 32B is arranged near the end of the short piece 34E opposite to the end.

As a result, the first zigzag sipe 32A is formed in the center portion of the shoulder block 20 in the tire width direction.
A pseudo circumferential sipe 35 extending along the tire circumferential direction is formed by the half of the long short piece 33E on the terminal end side and the short piece 34E of the second zigzag sipe 32B. The two-dot chain line in FIG. 3 indicates the center line of the pseudo circumferential sipe 35.

The end of the long short piece 33E of the first zigzag sipe 32A and the second zigzag sipe 32 are connected.
The distance δ1 from B is preferably in the range of 0.1 to 1.0 mm, more preferably in the range of 0.3 to 0.5 mm.

The short piece 34 of the second zigzag sipe 32B
The distance δ2 between E and the first zigzag sipe 32A is 0.
The range of 1 to 1.0 mm is preferable, and 0.3 to 0.5 m
The range of m is more preferable.

The angle θ1 of the sipe row 32 in the tire width direction with respect to the tire circumferential direction measured in the clockwise direction is 6
The range of 0 to 120 ° is preferable. (Lipe sipe) In the block-shaped portion 26B, a plurality of zigzag-shaped sipes 36 that are substantially parallel to the transverse main groove 18 are formed.

The rib-shaped portion 26A includes the block-shaped portion 2
A plurality of zigzag-shaped sipes 38 whose inclination directions are different from those of the 6B sipes 36 are formed.

Here, it is preferable to set the amplitude of the sipe 38 formed on the rib-shaped portion 26A smaller than the amplitude of the sipe 36 formed on the block-shaped portion 26B. (Center rib sipe) Auxiliary groove 3 of the center rib 22
Short pieces 42 inclined in mutually opposite directions are alternately connected between 0 and the auxiliary groove 30 to form a zigzag shape, which extends from one end edge in the tire width direction toward the tire equatorial plane CL, and A first zigzag sipe 40A terminating near the tire equatorial plane CL, and a first zigzag sipe 40A
Is arranged on the extension line of the first zigzag sipe 40A to form a pair, and short pieces 42 inclined in opposite directions are alternately connected to form a zigzag shape, and the tire equator is formed from the other end in the tire width direction. The second zigzag sipe 40B extending to the plane CL and terminating near the tire equatorial plane CL.
A plurality of sipe rows 40 in the tire width direction are formed in the tire circumferential direction.

Here, the short piece 42E including the end portion of the second zigzag sipe 40B on the tire equatorial plane CL side has a length approximately twice that of the other short pieces 42.

The end of the short piece 41E of the first zigzag sipe 40A on the tire equatorial plane CL side is arranged near the center of the long piece 42E of the second zigzag sipe 40B.

Further, the end portion of the long short piece 42E of the second zigzag sipe 40B has a first end adjacent to the tire circumferential direction.
The zigzag sipe 40A is arranged near the end of the short piece 41E opposite to the end.

As a result, the center rib 22 is formed at the center in the tire width direction with the half of the long short piece 42E of the second zigzag sipe 40B on the terminal end side and the short piece 41E of the first zigzag sipe 40A. The pseudo circumferential sipe 43 extending along the tire circumferential direction is formed. The two-dot chain line in FIG. 4 indicates the center line of the pseudo circumferential sipe 43.

The end portion of the long short piece 42E of the second zigzag sipe 40B and the first zigzag sipe 40 are arranged.
The distance δ3 from A is preferably in the range of 0.1 to 1.0 mm, more preferably in the range of 0.3 to 0.5 mm.

The short piece 41 of the first zigzag sipe 40A
The distance δ4 between the terminal end portion of E and the second zigzag sipe 40B is preferably in the range of 0.1 to 1.0 mm,
The range of 3 to 0.5 mm is more preferable.

The angle θ2 of the sipe row 40 in the tire width direction with respect to the tire circumferential direction measured in the clockwise direction is 6
The range of 0 to 120 ° is preferable.

The overall negative rate of the tread 12 is preferably in the range of 20 to 35%, and the negative rate of the tread central region 12C may be set lower than the overall negative rate of the tread 12. preferable.

The tread pattern of the pneumatic tire 10 according to the present embodiment is set as shown in FIG.
As shown in (3), the shape is point-symmetrical (with respect to a point (not shown) on the tire equatorial plane CL).

In the pneumatic tire 10 of this embodiment, the overall negative ratio of the tread 12 is 27%, the negative ratio of the tread central region 12C is 26.7%, and the first circumferential main groove 14 has a groove width of 6.5 mm, groove depth 10 mm, second
The circumferential main groove 16 has a groove width of 5.5 mm and a groove depth of 10 m.
m, the width of the transverse main groove 18 is 6 mm at the end portion on the first circumferential main groove 16 side, 7.5 mm at the ground contact end 12E, and the groove depth is 10 m.
m, the angle θ formed by the transverse groove 18 and the sub groove 24 is 57 degrees, the sub groove 24 has a width of 2.5 mm, a groove depth of 7.5 mm, and a narrow groove 2.
8 has a width of 1.0 mm, a groove depth of 7.5 mm, and an auxiliary groove 30
Has a width of 2.0 mm, a groove depth of 7.5 mm, and rib-shaped portions 2
The width (average) of 6A is 15 with a tread width on one side of 1 / 2W
%, Each sipe has a width of 0.5 mm and a depth of 8.0 (the deepest part) mm.

Further, δ1, δ2, δ3, and δ4 are each 0.3 mm, and the angle of the tire width direction sipe row 32 and the tire width direction sipe row 40 with respect to the tire circumferential direction is about 100 degrees in the clockwise direction. is there. (Operation) Next, the operation and effect of the pneumatic tire 10 of the present embodiment will be described.

In the pneumatic tire 10 of this embodiment, since the two first circumferential main grooves 14 are arranged in the tread central region 12C and the second circumferential main grooves 16 are arranged on both sides thereof, respectively. Basic drainage performance and skid performance on snow can be secured.

Since a plurality of transverse main grooves 18 extending in the tire width direction are arranged in the tread 12 and a plurality of shoulder blocks 20 having a plurality of tire width direction sipe rows 32 extending in the tire width direction are arranged on the shoulder side, The on-ice performance is improved by the lug groove component and the edge component in the tire width direction.

Since the pseudo circumferential sipe 35 extending in the tire circumferential direction is arranged at the center of the shoulder block 20 in the tire width direction, when traveling on ice, the water film in the central region of the block is quickly taken into the sipe to brake on ice. The performance can be improved.

By disposing the pseudo circumferential sipes 35 on the shoulder block 20, the edge component in the tire circumferential direction is increased, and the cornering performance during traveling on ice is improved.

The sipe row 32 in the tire width direction is 1 in the middle portion.
Since the shoulder block 20 is rigid because it is divided, it is possible to prevent the shoulder block 20 from collapsing when a force is applied in the front-rear direction such as traction and braking, and to brake on all road surfaces on ice, snow, wet and dry, and It improves traction performance and also improves maneuverability.

In the land portion 26, the auxiliary groove 24 is
Since the pseudo water film on the ice in the vicinity of the center in the tire width direction of 6 is removed during traveling on ice and the water film on the road surface during traveling on wet road surface, the performance on ice and the wet performance can be improved.

Since the auxiliary groove 24 is not connected to the adjacent transverse main groove 18, the rigidity of the land portion 26 does not become too low,
There is no adverse effect when running on a dry road surface.

The sub-groove 24 extends to the outside in the tire width direction from the end of the transverse main groove 18 on the side of the first circumferential main groove.
The lug groove component in the tire width direction increases, which is effective for traction on ice and snow and braking performance.

Since the rib portion 26A which is continuous in the tire circumferential direction is left on the land portion 26, the actual ground contact area can be secured, which is advantageous for the performance on ice. Further, since the sipe 38 having a small amplitude, which is advantageous for the braking performance on ice, is formed in the rib-shaped portion 26A, it is further advantageous for the braking performance on ice.

In the land portion 26 between the first circumferential main groove 14 and the second circumferential main groove 16, sipe 36 and sipe 38 having different inclination directions are formed. There is no danger of flowing in one direction.

The center rib 22 has a plurality of auxiliary grooves 30 formed in the tire circumferential direction and is formed into a block row.
It is advantageous for traction performance and braking performance on snow. In addition, on all snow, ice, wet, and dry road surfaces, straight-line stability is increased and the steering wheel feels solid.

A pseudo circumferential sipe 43 extending in the tire circumferential direction is arranged in the center of the center rib 22 in the tire width direction. Therefore, when traveling on ice, the water film in the rib central region is quickly taken into the sipe to brake on ice. The performance can be improved.

A pseudo circumferential sipe 43 is attached to the center rib 22.
By arranging, the edge component in the tire circumferential direction increases, and the cornering performance when traveling on ice is improved.

The sipe row 40 in the tire width direction is 1 in the middle portion.
The center rib 22 (auxiliary groove 30
The rigidity of the (block-shaped section divided by) is secured, and it is possible to suppress the collapse when traction, braking, etc. are applied in the front-back direction, braking on icy, snowy, wet and dry road surfaces, and traction performance. And the maneuverability can be improved.

Since the transverse main groove 18 and the first circumferential main groove 14 are connected by the narrow groove 28, the rigidity of the rib portion 26A can be adjusted so that the performance on ice is improved.

The overall negative rate of the tread 12 is set to 2
Since it is within the range of 0 to 35%, the actual ground contact area is increased as compared with the tire of the conventional example, and the braking performance on ice and the traction performance on ice can be improved.

Since the negative rate of the tread central area 12C is set to be smaller than the overall negative rate of the tread 12, the ratio of the land portion in the tread central area 12C is equal to the land portion in the tread side area 12S on both sides thereof. The ratio becomes larger than the above ratio, which is effective for braking performance on ice, and is also effective for suppressing uneven wear (so-called center wear) of the tire center portion.

The central region 12C of the tread is a region that greatly contributes to the performance on ice, the performance on snow, the wet performance and the like, and by suppressing the wear here, the performance on ice, the performance on snow and the wet performance are maintained for a long time. become able to.

Further, since the tread pattern of the pneumatic tire 10 of this embodiment is point-symmetrical with respect to a point (not shown) on the tire equatorial plane CL, the tire mounting direction is not limited, This facilitates replacement of tire mounting positions (so-called rotation) and is effective in preventing uneven wear. [Other Embodiments] In the above embodiment, one pseudo circumferential sipe 35 is formed in the center of the shoulder block 20, and one pseudo circumferential sipe 43 is formed in the center of the center rib 22. The present invention is not limited to this, and in the case where the width of the block is particularly wide, etc., as long as the block rigidity does not deteriorate other performance, for example, the shoulder block 20 is illustrated in FIGS. 6 and 7. As described above, the tire width direction sipe row 32 including the first zigzag sipe 32A, the second zigzag sipe 32B, and the third zigzag sipe 32C is formed to arrange the two pseudo circumferential sipe 35. The number of pseudo circumferential sipes 35 may be three or more in some cases.

It should be noted that each block may be further provided with a zigzag sipe extending in the tire circumferential direction without interruption unless other performance is deteriorated. (Test Example) In order to confirm the effect of the present invention, a pneumatic tire of a conventional example and a pneumatic tire of an example to which the present invention is applied are prepared, and snow feeling performance, snow braking performance, snow traction performance, Ice feeling performance,
The on-ice braking performance and wet hydroplaning performance were compared.

The pneumatic tire of the example is the pneumatic tire described in the above embodiment.

On the other hand, the conventional pneumatic tire has a tread pattern similar to that of the pneumatic tire of the embodiment as shown in FIG. 5, but the shoulder block and the center rib are each provided with pseudo circumferential sipes. Not provided.
The sipe 32 of the shoulder block 20 is continuous without interruption in the tire width direction, and the center rib 2
The second sipe 40 is also continuous in the tire width direction without interruption. In the plan view of the tread of the conventional pneumatic tire, the same components as those of the pneumatic tire of the embodiment are designated by the same reference numerals.

The tire size is PS for all tires.
R205 / 65R15.

The test method and evaluation will be briefly described below. -Snow feeling performance: Comprehensive evaluation of braking performance, starting performance, straightness and cornering performance on a test course on a snow-covered road surface (by a test driver). The evaluation is represented by an index with the feeling of the conventional example being 100, and the larger the value, the better the feeling on snow. -Brake performance on snow: Measures the braking distance when fully braking on compressed snow from 40 km / h. The evaluation is represented by an index with the reciprocal of the braking distance of the conventional example being 100, and the larger the value, the better the snow braking performance.・ Traction performance on snow: Measures the acceleration time from the start at a distance of 50 m on compressed snow. The evaluation is represented by an index in which the reciprocal of the acceleration time of the conventional example is 100, and the larger the value, the better the snow traction performance. -Ice feeling performance: Comprehensive evaluation of braking performance, starting performance, straightness and cornering performance (by test driver) on a test course on an ice plate surface. The evaluation is represented by an index with the feeling of the conventional example being 100, and the larger the value, the better the feeling on ice. -Brake performance on ice: Measures the braking distance when fully braking on an ice plate from 20 km / h. The evaluation is represented by an index with the reciprocal of the braking distance of the conventional example being 100, and the larger the value, the better the braking performance on ice. Wet hydroplaning performance: Feeling evaluation of the critical speed of hydroplaning generation when passing through a wet road surface at a water depth of 5 mm.

[0096]

[Table 1] From the test results, it can be seen that the pneumatic tires of the examples to which the present invention is applied have significantly improved all performances as compared with the pneumatic tires of the conventional examples.

[0097]

As described above, since the pneumatic tire according to claim 1 has the above-mentioned structure, it has an excellent effect that the performance on ice and the block rigidity can be improved.

[Brief description of drawings]

FIG. 1 is a plan view of a tread of a pneumatic tire according to an embodiment of the present invention.

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

FIG. 3 is an enlarged plan view of a shoulder block (right side) of the pneumatic tire according to the embodiment of the present invention.

FIG. 4 is an enlarged plan view of a center rib of the pneumatic tire according to the embodiment of the present invention.

FIG. 5 is a plan view of a tread of a conventional pneumatic tire.

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

FIG. 7 is a plan view of a shoulder block of a pneumatic tire according to still another embodiment of the present invention.

[Explanation of symbols] 10 pneumatic tires 12 treads 14 First circumferential main groove 16 Second circumferential main groove 18 Transverse main groove 20 shoulder block 22 Center rib 24 Secondary groove 26 Land 32 tire width direction sipe row 32A Zigzag sipe 35 Pseudo circumferential sipe 40 tire width direction sipe row 43 Pseudo circumferential sipes

Claims (4)

[Claims] 1. A tread is provided with a plurality of blocks partitioned by a plurality of grooves intersecting with each other, and a plurality of corrugated zigzag sipe extending in the tire width direction is formed in the block in the tire circumferential direction. And at least one wavy zigzag sipe extending along the tire circumferential direction
In the pneumatic tire formed by more than one, the block is substantially connected without connecting a plurality of zigzag-shaped sipes formed in a zigzag shape by alternately connecting short pieces inclined in mutually opposite directions in the tire width direction. A plurality of tire width direction sipe rows arranged in a straight line are provided in the tire circumferential direction, and in the plurality of tire width direction sipe rows, a short piece including one end portion adjacent to each other is an end portion of the other zigzag sipe. The length of the short piece is at least twice as long as that of the short piece, the end of the short piece is arranged near the center of the long piece, and the end of the long piece is in the tire circumferential direction. By being arranged near the end on the side opposite to the terminal end side of the shorter piece of the other adjacent zigzag sipe,
The pneumatic tire, wherein one or more pseudo circumferential sipes extending substantially in a zigzag shape in the tire circumferential direction are formed near the central portion in the tire width direction of the block. 2. The distance between the terminal end and the short piece of the other zigzag sipe closest to the terminal end is within a range of 0.1 to 1.0 mm. The pneumatic tire according to claim 1. 3. The block is formed with three or more sipe rows in the tire width direction, and one sipe row in the pseudo circumferential direction is formed.
The pneumatic tire according to claim 1 or 2, wherein the pneumatic tire is fully formed. 4. The plurality of zigzag-shaped sipes in a tire width direction sipe row are formed from straight short pieces, have substantially the same amplitude and the same wavelength, and are arranged on the same straight line. Measure around 6
The pneumatic tire according to any one of claims 1 to 3, wherein the pneumatic tire is in the range of 0 to 120 degrees.