JP2001138717A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a running performance on an ice road. SOLUTION: At least a part of a tread surface 3 is formed using a slide proofing rubber material G1 containing 2-40 pts.wt. column-like material 5 that has 10-4-4.0 mm2 bottom area and 0.1-15 mm length and made of material applying an edge effect to a road surface in 100 pts.wt. rubber base material. The column-like material 5 orients its longitudinal direction at 40-90 deg. angle in relation to the tread surface 3. The tread surface 3 is provided with a siping S formed by cutting after tire vulcanization molding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire capable of improving running performance on icy and snowy roads.

[0002]

2. Description of the Related Art In recent years, tires (for example, studless tires) having improved running performance on icy and snowy roads have been mixed with organic or inorganic short fibers in tread rubber which is in contact with the road surface. . Such short fibers are known to be randomly oriented and, for example, substantially oriented along the thickness direction of the tread rubber. The short fibers protrude from the tread rubber like a beard and scratch the road surface (edge effect) as a main effect, and can increase the coefficient of friction on icy and snowy roads.

[0003] In this type of tire, usually,
A block pattern in which a large number of blocks are formed on the tread surface is employed, and a large number of sipings (narrow grooves) extending substantially in the tire axial direction are formed in this block.

[0004]

By the way, a plurality of the sipes are usually engraved per block, and the sipes are vulcanized by a knife blade provided in a tire vulcanizing mold. However, by pushing the knife blade into the rubber together with the rubber flow during vulcanization molding, the orientation of the short fibers and the like is irregularly disordered,
There is a problem that the effect of scraping the road surface by short fibers or the like cannot be sufficiently obtained. For this reason, in order to further improve the frictional force, for example, rubber is softened. However, in this method, the tread surface is severely worn and the tire life is significantly shortened. Further, the tread rubber containing the short fibers is generally effective on icy and snowy roads, but has a problem in that the contact area of the rubber is reduced on a normal dry asphalt road surface, so that the grip force is rather lowered.

The present invention has been devised in view of these problems. In the first invention, a rubber material for anti-slipping is prepared by mixing a columnar material having a predetermined shape with 100 parts by weight of a rubber base material. While forming at least a part of the tread surface using
Orientation of the columnar material at an angle of 40 to 90 ° with respect to the tread surface and providing a siping formed by cutting after tire vulcanization molding. It is an object of the present invention to provide a pneumatic tire capable of sufficiently suppressing running and improving running performance on ice and snowy roads.

In the second invention, at least a part of the tread surface is formed by using the anti-slip rubber material, and the tread surface is formed by a first grounding portion made of the anti-slip rubber material, A pneumatic tire capable of suppressing a decrease in grip on dry asphalt roads while improving running performance on icy and snowy roads, based on including a second grounding portion made of a rubber material containing no material. And

[0007]

First, a first aspect of the present invention is to provide a rubber base material having a base area of 10 ^{-4 to} 4.0 mm ² and a length of 0.1 to 15 mm in 100 parts by weight of a rubber base material and an edge with respect to a road surface. At least a part of the tread surface is formed using an anti-slip rubber material containing 2 to 40 parts by weight of a columnar material made of a material exhibiting an effect, and the length direction of the columnar material is 40 to 90 with respect to the tread surface. The pneumatic tire is characterized in that the pneumatic tire is oriented at an angle of ゜ and a siping formed by cutting after tire vulcanization molding is provided on the tread surface.

Thus, in the pneumatic tire according to the first aspect of the present invention, the oriented pillars and the like effectively scratch the road surface, thereby increasing the coefficient of friction on icy and snowy roads and improving running performance. In addition, the siping is formed by cutting after tire vulcanization molding, so that the orientation of the columnar material can be prevented from being disordered irregularly as compared with the case where the siping is formed by vulcanization, and the orientation is effectively maintained. As a result, it is possible to effectively improve running and braking performance on ice and snow roads (hereinafter, these may be simply collectively referred to as “running performance”). The tread surface refers to a surface that comes into contact with a road surface under an internal pressure and load determined by a standard such as JATMA by mounting a tire on a rim.

Although the columnar material is not particularly limited, it is preferable to include a columnar or prismatic glass fiber in order to enhance the edge effect. The tread surface is useful for generating a large driving force by forming at least one row of blocks in which blocks are arranged in the tire circumferential direction or a row of ribs continuous in the tire circumferential direction. The durometer A hardness of the anti-slip rubber material is set to 40 to 60.
By setting ゜, the adhesion to the road surface is increased, and the contact performance can be further improved, so that the traveling performance on the icy and snowy road can be further improved.

According to a second aspect of the present invention, there is provided a rubber base material having a base area of 10 ^{-4 to} 4.0 mm ² and a length of 0.1 to 1 per 100 parts by weight of a rubber base material.
At least a part of the tread surface is formed by using a rubber material for anti-skid including 2 to 40 parts by weight of a columnar material having a thickness of 5 mm and having an edge effect on a road surface. While the tread surface is oriented at an angle of 40 to 90 ° with respect to the surface, the tread surface has a first grounding portion formed using the anti-slip rubber material, and a second ground material made of a rubber material that does not include a columnar material. A pneumatic tire including a ground contact portion.

[0011] For example, the tread surface may include the first ground portion at the center of the tread surface and second ground portions extending to the tread edge on both sides thereof. In this case, since the anti-slipping effect is obtained at the center of the tread surface where a large force acts during driving, the starting wheel with less slippage even when traveling on icy and snowy roads, especially for driving wheels,
A driving action is obtained. At this time, by setting the width of the first ground contact portion in the tire axial direction to, for example, 0.2 to 0.6 times the tread width which is the tire axial distance between tread ends, grip on a dry asphalt road surface is achieved. Power and driving performance on ice and snow can be improved in a well-balanced manner.

[0012] The tread surface may include the second grounding portion at a central portion of the tread surface and the first grounding portions on both sides thereof. In this case, since a slip-preventing action is obtained on both sides of the tread surface where a large force is applied during turning, a turning operation with less slippage can be obtained even when traveling on an icy road, especially for steering wheels. Also, at this time, the width of the first ground contact portion in the tire axial direction is 0.1 to 0.1 of the tread width, which is the distance between the tread ends in the tire axial direction.
By setting the ratio to 0.25, it is possible to improve the grip on a dry asphalt road surface and the turning performance on an icy road in a well-balanced manner.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional view of the pneumatic tire of the present embodiment, and FIG. 2 is a developed view of a tread surface thereof. The pneumatic tire 1 of the present embodiment has a tread portion 2 and at least a part of a tread surface 3 serving as a ground contact surface of the tread portion 2 is formed of an anti-skid rubber material G1 so that the tire can travel on icy and snowy roads. It is configured as an improved so-called studless tire.

In the present embodiment, the tread rubber 4 disposed on the tread portion 2 includes a base rubber 4a positioned inside between the tread ends E, E in the tire radial direction, and a tread rubber 4 disposed outside the base rubber 4a. In addition, in the present embodiment, the cap rubber 4b includes the cap rubber 4b that forms the tread surface 3 and the wing rubbers 4c and 4c that are arranged so as to cover both side edges of the cap rubber 4b. Has formed. The tread rubber 4 is disposed radially outward of the belt layer 7 for loosely fastening the carcass 6 forming the skeleton of the tire.

The anti-slip rubber material G1 is made of a rubber base material 100
It is configured to include 2 to 40 parts by weight of the columnar material 5 having a predetermined shape in the weight part. As the rubber substrate, for example, a diene rubber is preferable, and more specifically, natural rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroprene rubber, acrylonitrile butadiene rubber, or the like is blended with one or more kinds. Can be used.

The columnar member 5 is made of a material which causes the anti-skid rubber member G1 to exert an edge effect on a road surface. That is, it is first necessary that the columnar material 5 be made of a material which is kneaded and dispersed in the rubber base material and does not disappear even by vulcanization. Further, the columnar member 5 projects in a beard shape from the surface of the rubber base material, for example, and the columnar member directly exerts an edge effect by scraping the road surface directly. In this case, the columnar member 5 is required to have a bending rigidity that is not easily broken. Further, when the columnar member 5 falls off from the rubber surface due to the progress of rubber abrasion or the like, the edge effect can be indirectly exerted also by the small holes remaining on the rubber surface on which the columnar member 5 is embedded. It is also possible to adsorb a water film on ice using the small holes.

Examples of the material of the columnar member 5 include, for example, organic materials such as nylon, polyester, aramid, rayon, vinylon, aromatic polyamide, cotton, cellulose resin, crystalline polybutadiene, metal fibers, and whiskers. , Boron, glass fiber, etc., and these can be used alone or in combination of two or more. It is particularly preferable to use a nonmetallic material having a small difference in wear rate with rubber, particularly glass fiber. Further, the columnar member 5 may be subjected to a surface treatment or the like necessary for improving the adhesion to the rubber base material.

The compounding amount of the columnar material 5 depends on the rubber base material 1
The amount is 2 to 40 parts by weight, more preferably 15 to 30 parts by weight, based on 00 parts by weight. If the columnar material 5 is less than 2 parts by weight, the running performance on ice and snow roads cannot be sufficiently enhanced,
Conversely, if it exceeds 40 parts by weight, the crack resistance of the rubber tends to decrease.

The columnar member 5 is made of glass fiber in the present embodiment. For example, as shown in FIGS.
It is desirable to be formed in a cylindrical or prismatic shape. When making a prismatic shape, especially by making it a triangular prism shape or hexagonal prism shape,
The edge of the columnar material 5 itself further increases, so that a higher edge effect can be expected. The bottom area A of the columnar member 5 is set to 10 ^{-4 to} 4.0 mm ² , and the length L is set to 0.1 to 15 mm. The bottom area A of the columnar member 5 is 10
^-4 If the length L of mm ² less than or columnar member 5 is less than 0.1 mm, scratching effect is lowered road surface by columnar member 5 itself,
Conversely, the bottom area A is larger than 4.0 mm ² or the length L is 15
If it is larger than mm, the columnar material 5 becomes too large, so that the adhesion to rubber is reduced and the wear resistance and crack resistance are reduced. From this viewpoint, the bottom area A of the columnar member 5 is 10 ⁻² to
It is particularly desirable that the length L be 4.0 mm ² and the length L be 0.3 to 15 mm. Both the bottom area A and the length L are average values.

The anti-slip rubber material G1 has a durometer A hardness of 40 to 60 °, more preferably a durometer A hardness of 40 to 6 when measured in an atmosphere of -10 ° C.
0 °, more preferably 45 ° to 60 °. As a result, flexibility is ensured even at low temperatures, and the contact performance with the road surface is further improved to improve running performance on icy and snowy roads, and it is also useful to maintain steering stability on dry asphalt road surfaces. The "durometer A hardness" is a rubber hardness measured by a durometer type A based on JIS-K6253, and is measured to be the hardness of the anti-slip rubber material G1 (in the tire radial direction).

Most of the columnar member 5 (for example, 90% or more) is oriented in a state where its length direction is substantially perpendicular to the tread surface 3 at an angle of 40 to 90 °. As a method for obtaining the rubber in which the columnar member 5 is oriented in this way, for example, a calender roll r can be used as shown in FIG. As is known, an unvulcanized rubber material m in which, in addition to the rubber base material and the columnar material 5, predetermined chemicals required for vulcanization molding are blended as required, are rolled by calender rolls r and r. In this case, the length direction of the columnar material 5 is along the rolling direction X.

The rolled rubber sheet g is folded and laminated as shown in FIG. 4A to form a predetermined width, whereby the columnar member 5 is oriented in the Z direction perpendicular to the rolling direction. By using this rubber laminate such that the Z direction is the tire radial direction, a material in which the columnar material 5 is oriented substantially perpendicular to the tread surface 3 can be obtained.

As shown in FIG. 4 (b), a rubber sheet g in which the columnar members 5 are oriented in the rolling direction is laminated in the thickness direction, and this laminate is placed on a surface J perpendicular to the orientation direction of the columnar members 5. May be used to obtain a similar material.

Then, if necessary, these materials are used as shown in FIG.
As shown in the figure, the tread rubber 4 is bonded to the base rubber 4a, the wing rubber 4c and the like, and the raw tire cover is formed using the tread rubber 4. The pneumatic tire 1 can be manufactured by vulcanizing the green tire cover. In the pneumatic tire 1 having such a tread surface 3, the oriented columnar member 5 or the like effectively scratches the road surface, or a small hole in the rubber surface formed by the columnar member 5 falling off the rubber. Thereby, the coefficient of friction between the road and the icy road can be increased, and the driving performance can be greatly improved.

In the pneumatic tire 1 of the present embodiment, the sipes S formed by cutting after the tire vulcanization molding are provided on the tread surface 2. In this example, all the sipes S are formed by the tire vulcanization molding. The example formed by the cutting of FIG. Generally, as shown in FIG.
When the siping S is formed using the knife blade K or the like, the orientation of the columnar material 5 existing in the flowing rubber is easily disturbed by the rubber flow or the like caused by the pressing of the knife blade K. Since the orientation is already fixed by the vulcanized rubber, the siping S
This prevents the orientation of the columnar material 5 from being disturbed. Accordingly, in the pneumatic tire of the present embodiment, since the disorder of the orientation state of the columnar member 5 after vulcanization is very small, the effect of improving running performance on icy and snowy roads can be further expected. In addition, since the orientation of the columnar material 5 is improved as compared with the conventional case, even if the rubber hardness of the anti-slip rubber material G1 is increased, the same level of performance on ice can be exhibited. The wear resistance of the material G1 can be improved to extend the tire life.

As shown in FIG. 2, the tread surface 3 is formed by a block pattern including five block rows BL in which the blocks B defined by the vertical grooves 10 and the horizontal grooves 11 are arranged in the tire circumferential direction, as shown in FIG. What was done is illustrated,
At least one, preferably a plurality of sipes S are formed in each block B. Note that the block row BL
Instead, the contact portion may be a row of ribs continuous in the tire circumferential direction. Further, the siping S is disposed at an inclination angle θ of, for example, 0 to 60 ° with respect to the tire axial direction, and can effectively increase the edge component of the block B.

The siping S can be formed in various shapes such as zigzag, wavy or a combination thereof in addition to a straight line as in this embodiment. It can be processed in various modes such as a semi-open type having only openings and a closed type in which both ends are terminated in a block. Note that siping S
Is preferably, for example, 3 to 25 mm, and the siping depth is, for example, 0.3 to 1.0 times the groove depth of the vertical groove 10.

FIG. 7 illustrates an embodiment of the second invention. The same parts as those in the above embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, the point that a part of the tread surface 3 is formed using the anti-skid rubber material G1 and the length direction of the columnar material 5 is the tread surface 3
For the point oriented at an angle of 40 to 90 ° with respect to
Similarly, the tread surface 3 is provided with the anti-slip rubber material G1.
And a second grounding portion 3b made of a rubber material G2 that does not include the columnar member 5.

As described above, the anti-slip rubber material G1 containing the columnar material 5 generates an effective frictional force on an icy and snowy road, but has a rubber contact area with a normal dry asphalt road. Therefore, there is a problem that the grip force is reduced due to a decrease in the grip force. Thus, in the present embodiment, the tread surface 3 includes the second ground contact portion 3b made of the rubber material G2 that does not include the columnar member 5, thereby achieving both the traveling performance on ice and the dry grip performance.

The running performance of the tire differs depending on where on the tread surface 3 the first ground contact portion 3a is arranged. The tread surface 3 of the present example has the first ground portion 3a at the center of the tread surface 3 and has second ground portions 3b extending to the tread edge E on both sides thereof. Generally, a large force acts on the central portion of the tread surface 3 at the time of starting, accelerating, and the like. By arranging the anti-skid rubber material G1 on this portion, the driving performance at the time of starting on a snowy road, accelerating, etc. Help to improve. That is, it is suitable as a driving wheel tire to be mounted on the driving wheel. On the other hand, tread surface 3
Is provided with a second contact portion 3b made of a rubber material G2 that does not include the columnar member 5 on the side portion in the axial direction, thereby increasing the grip force when turning on a dry asphalt road surface and improving steering stability. Is suppressed.

At this time, the width W1 of the first ground contact portion 3a in the tire axial direction (including the width of the groove that does not contact the ground) is set, for example, between the tread ends E, which are the axially outer ends of the tread surface 3, and the tire shaft. The tread width TW, which is the directional distance, is 0.2 to 0.
By setting it to 6 times, more preferably 0.3 to 0.6 times, it is possible to improve the grip force on dry asphalt road surface and the driving performance on ice and snow road with good balance. If the width W1 of the first contact portion 3a is less than 0.2 times the tread width TW, the contact width of the first contact portion 3a becomes small, so that it tends to be difficult to obtain a high frictional force on icy and snowy roads. On the other hand, when it exceeds 0.6 times, the contact width of the second contact portion 3b becomes small, so that the allowance for the grip force on the dry asphalt road surface becomes relatively large. The first ground contact portion 3a is arranged substantially at the center of the tire equator C.

FIG. 8 shows another embodiment of the second invention. The tread surface 3 of the present embodiment has the second ground portion 3b at the center of the tread surface 3, and has the first ground portions 3a on both sides thereof. Generally, a large lateral force acts on a side portion (a so-called shoulder portion) of the tread surface 3 at the time of turning. By arranging the anti-slip rubber material G1 on this side portion, turning performance particularly on an icy road is improved. Help. Such a tire is suitable as a steering wheel tire suitable for being mounted on a steering wheel on which a particularly large lateral force acts during turning. On the other hand, by providing the second ground contact portion 3b made of the rubber material G2 not including the columnar material 5 at the center of the tread surface 3, the grip on the dry asphalt road surface is increased, and the drive performance and the like are reduced. Is suppressed.

In such a rubber arrangement, the width W2 of the first ground contact portion 3a on each side in the tire axial direction should be 0.1 to 0.25 times, more preferably 0.1 to 0.2 times the tread width TW. It is desirable to make it 15 to 0.25 times. This is because this range mainly bears a large lateral force during cornering.

Further, the tread surface 3 of the present embodiment exemplifies the one in which the rubber material G2 not including the columnar material 5 is exposed within a small width W3 from the tread ends E, E in the tire axial direction. This width W3 is 0.05 to 0.1 of the tread width TW.
It is desirably 5 times, more preferably 0.10 to 0.15. Since the anti-slip rubber material G1 includes the columnar material 5, the rubber material G2 does not include the columnar material 5 around the tread end E because the rubber material G1 has a tendency to be slightly inferior in wear resistance, crack resistance, tear resistance and the like. By exposing the tire with a small width, it is possible to effectively prevent chipping of rubber at the tread end E, cracks, and the like, and improve the appearance of the tire over a long period of time. The rubber material G2 is made of a rubber material having higher wear resistance than the anti-slip rubber material G1.

Although the second invention has been described in detail above, it is preferable to provide a siping S formed by cutting after vulcanization as in the first invention in these examples. As shown in FIGS. 7 and 8, the siping includes a first siping S1 including the first ground portion 3a and a second siping S1.
And the second siping extending only from the ground portion 3b. And, for example, only the second siping is irrelevant to the anti-slip rubber material G2, and therefore, a mold formed by vulcanization using the knife blade K of the mold M is exemplified. This can reduce a decrease in tire productivity. FIG.
As shown in (1), a first ground contact portion 3a made of the anti-skid rubber material G1 may be provided on both the center portion and the side portion of the tread surface 3. In this case, although the grip on the dry asphalt road surface is slightly improved, it is possible to simultaneously improve both performances such as driving and turning on an icy road.

[0036]

EXAMPLES (Example 1) A studless tire (Example) in which siping was vulcanized and then cut and cut, and a studless tire (comparative example) in which siping was formed by a knife blade of a vulcanizing mold. The test was conducted on braking performance on ice, running feeling on ice, feeling on snow, tire life, and the like. Tire size is 1
95 / 65R15. The depth of the vertical groove is about 8.5 mm, the depth of the siping is 6 mm, and the interval between the sipes is 10 mm. Further, Comparative Example 1, Examples 1 and 2 have the same block pattern having five rows of blocks, and Comparative Examples 2, 3 and 4 have the same rib pattern having five rows of ribs. The column-shaped material has an average bottom area of 0.
A glass fiber having a size of 3 mm ² and an average length of 0.8 mm was used, and 10 parts by weight of 100% by weight of the rubber base material was blended for each tire. The contents of the test are as follows.

<Breaking performance on ice> A test tire that ran on a dry asphalt road surface for about 200 km was mounted on a 2000-FR domestic displacement FR car, and the speed was 30 on an ice plate.
Lock braking from km / H was performed, and the braking distance until the vehicle stopped was measured. The evaluation was indexed by the following equation. Examples 1 and 2 (braking distance of comparative example 1) ÷ (braking distance of each tire) × 1
00 Examples 3 and 4 (braking distance of comparative example 2) ÷ (braking distance of each tire) × 1
The 00 index indicates that the larger the index, the better the braking performance on ice.

<Feeling on ice and snow> The above test vehicle travels on a test course consisting of an icy road and a snowy road, and the overall driving feeling including turning, braking, acceleration, etc. is implemented by the driver's sensuality. Comparative Examples 1 and 2 for Examples 1 and 2 and Comparative Example 2 for Examples 3 and 4
Was set to 100 and the evaluation was performed. The higher the value, the better.

<Tire Life> The test vehicle traveled about 4000 km on a general road, and the travelable distance when the groove depth was reduced by 1 mm was calculated from the remaining depth of the vertical groove on the tread surface at that time. For the block pattern tires, an index with the travelable distance of Comparative Example 1 as 100 is given by:
Further, the tire having the rib pattern was evaluated by an index with the travelable distance of Comparative Example 2 being 100. The larger the value, the longer the tire life.
Table 1 shows the test results.

[0040]

[Table 1]

As a result of the test, it was confirmed that the example of the present invention improved the braking performance on ice and the like in both the block pattern and the rib pattern as compared with the comparative example. In addition, even when the rubber hardness of the anti-skid rubber material was increased, braking on ice was maintained at the same level as in the comparative example, and it was confirmed that the tire life could be increased at this time.

(Example 2) Next, the tires (Examples 5 to 13) shown in FIGS.
Tests were performed on ice turning performance, dry grip, wet grip, etc. For comparison, a summer tire (Comparative Example 3) made of a rubber material for anti-skid and having no tread (Comparative Example 3) and a tire (Comparative Example 4) in which the entire surface of the tread surface was made of rubber material for anti-skid were also manufactured. Was performed and the performance was evaluated. The test method is as follows.

<Driving Performance on Ice> The coefficient of friction of the road surface on ice was measured and evaluated by an index with Comparative Example 3 being 100. The higher the value, the better. The friction coefficient was measured using an inside drum.
Under the condition of km / h, the slip rate was set at 10% and 60%.

<Turning performance on ice> Steady circular turning (about 40R) on an ice road surface at a speed of 30 to 40km / h at an air temperature of -1 ° C.
In addition to measuring the time, the index was evaluated by adding the sensuality of the driver. The higher the value, the better.

<Dry Grip Performance> The test vehicle equipped with the test tire was entered on a course of asphalt road surface with a radius of 100 m while increasing the speed stepwise, and the lateral acceleration (lateral G) was measured. The average lateral G of the front wheels at a speed of ８０80 km / h was calculated. The results are indicated by an index with Comparative Example 3 being 100, and the larger the value, the better.

<Wet grip performance> The test vehicle equipped with the test tire was entered on a course provided with a puddle having a depth of 5 mm and a length of 20 m on an asphalt road surface having a radius of 100 m while gradually increasing the speed. , The lateral acceleration (lateral G) was measured, and the average lateral G of the front wheels at a speed of 50 to 80 km / h was calculated. As a result, Comparative Example 3 was 100
The larger the numerical value, the better. Tables 2 and 3 show the test results.

[0047]

[Table 2]

[0048]

[Table 3]

As a result of the test, it was confirmed that the tire of the example improved the dry grip performance as compared with the comparative example 4 while improving the braking performance on ice and the like. Especially FIG.
In FIG. 8, it was confirmed that the driving performance on ice and that in FIG. 8 were improved in good balance with the dry grip performance.

[0050]

As described above, according to the first to third aspects of the present invention, the coefficient of friction on an icy and snowy road is improved by the columnar material or the like oriented substantially perpendicular to the tread surface effectively scratching the road surface. To improve driving performance. In addition, since the sipes formed by cutting after tire vulcanization molding are provided on the tread surface, the orientation of the columnar material is disturbed during vulcanization as compared with the case of molding sipes using a knife blade etc. Is prevented, and the effect of improving running performance on icy and snowy roads can be further expected. In addition, since the above-described orientation of the columnar material is improved as compared with the related art, for example, even if the rubber hardness of the anti-skid rubber material is increased, the same performance on ice as before can be exhibited. Can improve the wear resistance of the anti-slip rubber material and extend the tire life. When the hardness of the anti-slip rubber material is limited, the traveling performance on an icy road is improved because the adhesiveness on the icy road surface is increased.

Further, in the invention according to claims 4 to 6,
On the tread surface, a first anti-slip rubber column containing a columnar material
And a second ground contact portion made of a rubber material that does not include a columnar material, thereby achieving both running performance on ice and dry grip performance.

When the first ground contact portion is provided at the center of the tread surface and the second ground contact portions are provided on both sides of the tread surface, the driving performance at the time of starting or accelerating on an icy road is improved, and the dry performance is improved. The grip when turning on asphalt road surface can be enhanced.

When the second ground contact portion is provided at the center of the tread surface and the first ground contact portions are provided on both sides of the tread surface, turning performance on ice and snow roads is improved, and when starting on dry asphalt road surface, etc. Helps to increase grip.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a tread portion according to an embodiment of the first invention.

FIG. 2 is a development view of a tread surface.

FIGS. 3A to 3D are schematic diagrams illustrating columnar members.

FIGS. 4A and 4B are schematic views illustrating a method for producing a rubber material for anti-slip.

FIG. 5 is a cross-sectional view illustrating an unvulcanized tread rubber.

FIG. 6 is a partial cross-sectional view along the circumferential direction of the entire die.

FIG. 7 is a partial sectional view of a tread portion according to an embodiment of the second invention.

FIG. 8 is a partial sectional view of a tread portion according to another embodiment of the second invention.

FIG. 9 is a partial cross-sectional view of a tread portion according to another embodiment of the second invention.

[Explanation of symbols]

 2 Tread part 3 Tread surface 3a First grounding part 3b Second grounding part 5 Columnar material S Siping G1 Anti-skid rubber material E Tread end

Claims (6)

[Claims] 1. A base material having a base area of 10 ^{-4 in} 100 parts by weight of a rubber base material.
2 columnar member ～4.0Mm ² and length and made of material to exhibit the edge effect against 0.1~15mm Moreover road
At least a part of the tread surface is formed by using a rubber material for anti-slipping including 40 parts by weight, and a length direction of the columnar material is 40 to 90 with respect to the tread surface.
A pneumatic tire which is oriented at an angle of ゜ and has a siping formed by cutting after tire vulcanization molding on the tread surface. 2. The pneumatic tire according to claim 1, wherein the columnar member includes a glass fiber having a columnar or prismatic shape. 3. The tread surface has at least one row of blocks in which blocks are arranged in the tire circumferential direction or at least one row of ribs continuous in the tire circumferential direction, and has a durometer A hardness of 40 of the anti-skid rubber material. The pneumatic tire according to claim 1 or 2, wherein the angle is set to 60 °. 4. A base material having a base area of 10 ^{-4 in} 100 parts by weight of a rubber base material.
2 columnar member ～4.0Mm ² and length and made of material to exhibit the edge effect against 0.1~15mm Moreover road
At least a part of the tread surface is formed by using a rubber material for anti-slipping including 40 parts by weight, and a length direction of the columnar material is 40 to 90 with respect to the tread surface.
While the tread surface is oriented at an angle of ゜, the tread surface includes a first ground portion formed using the anti-slip rubber material, and a second ground portion formed of a rubber material that does not include a columnar material. Features pneumatic tires 5. The tread surface includes the first grounding portion at a central portion of the tread surface, and the second grounding portion extending to a tread end on both sides thereof, and the first grounding portion. The width in the tire axial direction, the tread width is the distance between the tread ends in the tire axial direction 0.2 to 0.2
5. The pneumatic tire according to claim 4, wherein said pneumatic tire is 0.6 times. 6. The tread surface has the second grounding portion at a center portion of the tread surface and has the first grounding portion on both sides thereof, and the first grounding portion has a tire grounding direction. The width is 0.1 to 0.1 of the tread width, which is the axial distance between the tread ends.
5. The pneumatic tire according to claim 4, wherein said pneumatic tire is 0.25 times.