JPH05131814A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To prevent break and crack from being produced in a narrow width region by arranging a high rigidity region having a higher rigidity than the narrow width region on the tire-width directional side of the narrow width region that forms a block together with wide width regions. CONSTITUTION:A block 12 is partitioned by sipes 14 into a narrow width region 16 of a width TS (not shown) and wide width regions 18 of a width TL (not shown) arranged on both sides of the narrow width region 16 in the circumferential direction of a tire, and the ratio TS/TL is set so as to satisfy the relationship 0.1<=TS/TL<=0.8. Further, the rigidity of the narrow width region 16 is set to be smaller than that of the wide width regions 18 on tire-width-directional both sides, so that at the time of driving or braking, the deformation of the wide width region 18 becomes smaller, and that of the narrow width region 16 becomes larger. Thus, break and crack can be prevented from being produced in the narrow width region.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire having a block pattern and sipes formed in the block.

[0002]

2. Description of the Related Art As a tire used for a vehicle traveling on a snowy and snowy road, a pneumatic tire has been proposed in which a sipe is provided on a block and the running performance on the snowy and snowy road is improved by the edge effect of this sipe.

This pneumatic tire is provided with a block in which a pair of sipes extending in the tire width direction are formed in parallel with each other in the tire circumferential direction.
The central region of the block sandwiched by the pair of sipes is a narrow region, the dimension in the tire circumferential direction is narrower than the regions on both sides of the sipes, and the rigidity is lower than the regions on both sides of the sipes. Therefore, when the pneumatic tire receives a frictional force from the road surface in the tangential direction of the tire outer circumference, the narrow region is deformed more than the regions on both sides of the sipe. Therefore, one of the pair of sipes of the block is closed and the other is opened, and the driving performance and the braking performance are improved by the edge effect.

[0004]

However, when the blocks are arranged on the tread of the pneumatic tire so that the narrow areas of the blocks are arranged in a row along the tire width direction, the narrow areas of low rigidity are formed in the tire width direction. Therefore, when the side force acts on the pneumatic tire, the deformation of the narrow region becomes large, and there is a problem that the narrow region is chipped or cracked.

In view of the above facts, the present invention is a pneumatic tire capable of preventing a chip or a crack generated in a narrow region of a block sandwiched by a pair of sipes when the block is provided with a pair of sipes. The purpose is to provide.

[0006]

According to the present invention, there is provided a narrow region sandwiched by a pair of sipes that substantially extend in the tire width direction, and a narrow region located on both sides of the narrow region via the sipes. And a wide area in which the tire circumferential direction average length TS of the narrow area and the tire circumferential average length TL of the wide area are 0.1 ≦ TS / TL ≦ 0.
The pneumatic tire having the relationship of No. 8 is characterized in that a high-rigidity region having higher rigidity than the narrow region is arranged laterally of the narrow region in the tire width direction.

[0007]

According to the present invention, the pneumatic tire is grounded,
When the block receives a frictional force in the tire outer peripheral tangential direction due to driving or braking, the block is deformed, but the tire circumferential average length T in the narrow region of the block sandwiched by sipes.
The relationship between S and the tire circumferential direction average length TL of the wide areas of the blocks located on both sides of the narrow area via the sipes is 0.
Since 1 ≦ TS / TL ≦ 0.8 is set, there is a difference in rigidity between the narrow region and the wide region, and the deformation of the narrow region is larger than that in the wide region. Therefore, in the block that receives the frictional force, one of the two sipes is closed and the other sipes are opened, and the running performance is improved by the edge effect of the tread side corner portion of the narrow area on the opened sipes side. (Driving performance and braking performance) are improved.

Further, in the pneumatic tire of the present invention, since a high rigidity region having a higher rigidity than the narrow region is arranged laterally in the tire width direction in the narrow region, even when an extreme frictional force acts, Since it does not concentrate on one sipe, the sipe does not open excessively and cracks occur at the bottom of the sipe. Furthermore, even if a side force acts and a complicated force mainly composed of a lateral component acts on the narrow region, the amount of deformation is moderated by the high rigidity region and decreases, especially at both ends of the narrow region. The occurrence of cracks is prevented. As described above, according to the present invention, it is possible to effectively prevent the occurrence of cracks in the narrow region and the chipping caused thereby.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, the pneumatic tire 10 to which the present invention is applied has a plurality of blocks 1 on its tread.
The block row 13 composed of 2 is arranged in the tire width direction (arrow B in FIG. 1).
Direction)) is provided in five rows. Each block row 13
The blocks 12 are arranged at predetermined intervals along the tire circumferential direction (direction of arrow A in FIG. 1).

As shown in FIG. 2, the block 12 has a substantially prismatic shape, and the dimension T of the block 12 in the tire circumferential direction (direction of arrow A in FIG. 2) is preferably 15 mm ≦ T ≦ 40 mm.
More preferably, it is set in the range of 20 mm ≦ T ≦ 35 mm. Here, when the tire circumferential dimension T of the block 12 exceeds 40 mm, the ground contact pressure decreases as the tire circumferential length of the block 12 increases, so that it is difficult to expect the edge effect, and the driving It is not preferable because the performance and the braking performance deteriorate. On the other hand, the tire circumferential dimension T is 15
If it is less than mm, the rigidity of the block 12 becomes too small, and as a result, it is difficult to expect the edge effect of the block 12, and the driving performance and the braking performance deteriorate, which is not preferable. In the present embodiment, the dimension W of the block 12 in the tire width direction (direction of arrow B in FIG. 2) is set to 34 mm.

A pair of sipes 14 extending linearly in the tire width direction and parallel to each other are provided at the center of the block 12 in the tire circumferential direction (the sipes referred to herein are preferably 1 mm or less, and more preferably 1 mm or less). Refers to those having a groove width of 0.6 mm or less).
In addition, in this embodiment, the groove width of the sipe 14 is set to 0.5 mm.

Both longitudinal ends of the sipes 14 reach the side wall 12A of the block 12 on the tire width direction side, and the blocks 12 are divided into three regions in the tire circumferential direction by the sipes 14. A region sandwiched by the pair of sipes 14 is a narrow region 16, and a region adjacent to both sides of the narrow region 16 in the tire circumferential direction is a wide region 18 as a high rigidity region.

As shown in FIG. 1, the block 12 is displaced from the block 12 adjacent to the tire width direction side by a predetermined dimension in the tire circumferential direction, and is adjacent to the narrow region 16 on the tire width direction side. The wide area 18 of the block 12 is disposed.

The ratio TS / TL between the width TS of the narrow region 16 and the width TL of the wide region 18 is 0.1 ≦ TS / T.
L ≦ 0.8, preferably 0.2 ≦ TS / TL ≦
It is set to 0.5. Note that the block 12 of this embodiment is
Indicates that the width TL of the wide region 18 in the tire circumferential direction is set to 14 mm, and the size TS of the narrow region 16 in the tire circumferential direction is 5 mm.
It is set to mm and the ratio T with the width TL of the wide area 18 is set.
The S / TL is about 0.36.

Therefore, the rigidity of the narrow region 16 is smaller than the rigidity of the wide regions 18 on both sides. Therefore, as shown in FIG. 3, when the block 12 comes into contact with the road surface 20 during driving or braking and a frictional force in the tire outer peripheral tangential direction (direction of arrow F in FIG. 3) acts on the block 12, the wide area 1
The deformation of No. 8 is small, and the deformation of the narrow region 16 is large.
As a result, the sipe 14 on the arrow F direction side of the two sipes 14 is closed, and the sipe 14 on the opposite side to the arrow F direction side is opened, and the corner portion 16B of the narrow region 16 on the tread surface 16A side.
The edge effect improves the performance on ice.

When the ratio TS / TL between the width TS of the narrow region 16 and the width TL of the wide region 18 exceeds 0.8, the difference in rigidity between the narrow region 16 and the wide region 18 becomes small, and during braking and When driving, the sipe 14 becomes difficult to open and the edge effect cannot be expected, and when it is less than 0.1, the rigidity of the narrow region 16 is excessively reduced and the durability of the narrow region 16 is reduced, which is not preferable.

Further, the pneumatic tire 10 of this embodiment is
Since the narrow regions 16 and the wide regions 18 having higher rigidity than the wide region 18 are alternately arranged in the tire width direction, they are concentrated on one sipe 14 even when an extreme frictional force acts. Therefore, the sipe 14 does not open excessively and the bottom portion 14A of the sipe 14 does not crack. Further, the side force F acts and the narrow region 16
Even if a complicated force having a lateral component as the main component acts, the amount of deformation is moderated and reduced by the wide region 18 having high rigidity, and the occurrence of cracks in the narrow region 16 especially at both ends is prevented. .. As described above, according to the present invention, it is possible to effectively prevent the occurrence of cracks in the narrow region 16 and the resulting chipping.

Next, a second embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 4, in the pneumatic tire 10 of the present embodiment, the block row 13 located at the center in the tire width direction (direction of arrow B in FIG. 4) and the block row 13 located at both ends in the tire width direction. And a sipe-free block 19 as a prismatic high-rigidity region in which no sipe is provided.
A block row 17 including the blocks is arranged, and these blocks without sipes 19 are arranged laterally of the narrow region 16 in the tire width direction. The tire-widthwise dimensions of these blocks without sipes are substantially the same as the tire-widthwise dimensions of the block 12, and the tire circumferential direction (arrow A direction in FIG. 4) is smaller than the tire circumferential dimension of the narrow region 16. It is made longer and has higher rigidity than the narrow region 16.

Therefore, the pneumatic tire 1 of this embodiment
Even at 0, a portion having higher rigidity than the narrow region 16 (the wide region 18 and the sipeless block 19) is disposed on the lateral side of the narrow region 16 in the tire width direction. Similar to the tire 10, even when an extreme frictional force acts, it does not concentrate on one sipe 14, so the sipe 14 does not open excessively and cracks occur at the bottom portion 14A of the sipe 14. .. Further, even if the side force F acts and a complicated force having a lateral component as a main component acts on the narrow region 16, the deformation amount thereof is a region having high rigidity (wide region 18 and sipeless block 19).
Are alleviated and reduced, and the occurrence of cracks in the narrow region 16, especially at both ends, is prevented. in this way,
Also in this embodiment, it is possible to effectively prevent the occurrence of cracks in the narrow region 16 and the chipping caused thereby.

Next, a third embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 5, in the pneumatic tire 10 of this embodiment, a high rigidity region continuous in the tire circumferential direction (direction of arrow A in FIG. 5) is formed in the center of the tire width direction (direction of arrow B in FIG. 5). Ribs 21 are provided. The rib 2
1, short sipe 23 extending from the side surface in the tire width direction toward the tread center is alternately arranged along the tire circumferential direction. The rigidity of the rib 21 in the tire width direction is set to be higher than that of the narrow region 16.

Therefore, the pneumatic tire 1 of this embodiment
Also in 0, since a portion having higher rigidity than the narrow region 16 (the wide region 18 and the rib 21) is arranged laterally of the narrow region 16 in the tire width direction, the pneumatic tire 10 of the first embodiment is provided. Similarly, even when an extreme frictional force acts, it does not concentrate on one sipe 14, so that the sipe 14 does not open excessively and cracks occur at the bottom portion 14A of the sipe 14. Further, even if the side force F acts and a complicated force having a lateral component as a main component acts on the narrow region 16, the amount of deformation is relaxed by the region having high rigidity (the wide region 18 and the rib 21). Therefore, the occurrence of cracks in the narrow region 16 is prevented especially at both ends. As described above, also in this embodiment, it is possible to effectively prevent the occurrence of cracks in the narrow region 16 and the chipping caused thereby.

Next, a fourth embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 6, block 1 of the present embodiment.
2 is the tire width direction of the narrow region 16 (arrow B direction in FIG. 6)
The dimension is slightly shorter than the dimension of the wide region 18 in the tire width direction, and the sipe 14 is slightly inclined with respect to the tire width direction.

Also in this embodiment, the adjacent blocks 1
The two are arranged so as to be offset from each other in the tire circumferential direction, and the wide regions 18 of the adjacent blocks 12 are arranged on the tire width direction side of the narrow region 16.

Therefore, the pneumatic tire 1 of this embodiment
At 0, as with the pneumatic tire 10 of the first embodiment, even when the extreme frictional force acts, one sipe 14
Since it does not concentrate at the bottom, the sipe 14 does not open excessively and the bottom portion 14A of the sipe 14 does not crack. Further, even if the side force F acts and a complicated force having a lateral component as a main component acts on the narrow region 16, the amount of deformation is moderated by the region of high rigidity (wide region 18) and becomes small. The generation of cracks in the narrow region 16 is prevented especially at both ends. As described above, also in this embodiment, it is possible to effectively prevent the occurrence of cracks in the narrow region 16 and the chipping caused thereby.

The longitudinal direction of the sipes formed on the block is preferably inclined within the range of 0 ° to 30 ° with respect to the tire width direction.

Further, as shown in FIG. 7, the bottom portion 14A of the sipe 14 may be formed in a substantially circular cross section in which the bottom portion 14A is swollen in the direction away from the other sipe. This prevents stress from being concentrated on the bottom portion 14A when the sipe 14 is opened, and prevents the bottom portion 14A from cracking.

In each of the above embodiments, one pair of sipes is provided for each block, but the present invention is not limited to this, and two or more pairs of sipes may be provided for each block. Good. Even in this case, a region having higher rigidity than the narrow region on the lateral side of the narrow region in the tire width direction (ribs, blocks without sipes, wide region of block, etc.)
Needless to say, it is provided. (Test Example) In Table 1 below, Comparative Example Product 1, Comparative Example Product 2,
The pneumatic tires of the comparative example product 3 and the product of the present invention were filled with normal internal pressures, respectively, and these pneumatic tires were mounted on the front wheels of a 10-ton truck with a constant load, and the 10-ton truck was run for 10,000 km. The results of measuring the number of cracks generated in the are shown.

The pneumatic tire of Comparative Example Product 1 is shown in FIG.
As shown in FIG. 9, the narrow regions 16 of the block 12 are arranged in a row in the tire width direction, and the pneumatic tire of Comparative Example product 2 has a block row 13 on one side in the tire width direction as shown in FIG. In the other four row blocks 13, the narrow regions 16 of the blocks 12 are arranged in a row in the tire width direction. Further, in the pneumatic tire of Comparative Example product 3, as shown in FIG. 10, the narrow regions 16 of the blocks 12 in the central three-row block row 13 are aligned in the tire width direction, and the block rows 13 on both sides in the tire width direction are arranged. Narrow area 16
Are arranged so as to be displaced in the tire circumferential direction with respect to the central three-row block row 13. The size of each of these test tires is 10.00R20, and the block size and the number of blocks per tire are all the same.

[0033]

[Table 1]

From the test results shown in Table 1, it has been clarified that the pneumatic tire 10 of the present invention can prevent the occurrence of cracks in the narrow region 16.

[0035]

Since the pneumatic tire of the present invention has the above-mentioned structure, when a pair of sipes is provided on the block, it is possible to prevent cracks and cracks occurring in the narrow region of the block sandwiched by the pair of sipes. It has an excellent effect of being able to.

[Brief description of drawings]

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

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

FIG. 3 is a side view seen from the tire width direction showing a state in which a block of the pneumatic radial tire according to the first embodiment of the present invention is deformed by receiving a frictional force from a road surface.

FIG. 4 is a diagram showing a tread pattern of a pneumatic radial tire according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a tread pattern of a pneumatic radial tire according to a third embodiment of the present invention.

FIG. 6 is a diagram showing a tread pattern of a pneumatic radial tire according to a fourth embodiment of the present invention.

FIG. 7 is a side view of a block of a pneumatic radial tire according to another embodiment of the present invention viewed from the tire width direction.

8 is a diagram showing a tread pattern of a pneumatic radial tire according to Comparative Example 1. FIG.

FIG. 9 is a diagram showing a tread pattern of a pneumatic radial tire according to Comparative Example 2.

FIG. 10 is a diagram showing a tread pattern of a pneumatic radial tire according to Comparative Example 3.

[Explanation of symbols]

 10 Pneumatic Tire 12 Block 14 Sipe 16 Narrow Area 18 Wide Area (High Rigidity Area) 19 Sipes-Free Block (High Rigidity Area) 21 Rib (High Rigidity Area)

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[Procedure amendment]

[Submission date] January 7, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

[Title of Invention] Pneumatic tire

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire having a block pattern and sipes formed in the block.

[0002]

2. Description of the Related Art As a tire used for a vehicle traveling on a snowy and snowy road, a pneumatic tire has been proposed in which a sipe is provided on a block and the running performance on the snowy and snowy road is improved by the edge effect of this sipe.

This pneumatic tire is provided with a block in which a pair of sipes extending in the tire width direction are formed in parallel with each other in the tire circumferential direction.
The central region of the block sandwiched by the pair of sipes is a narrow region, the dimension in the tire circumferential direction is narrower than the regions on both sides of the sipes, and the rigidity is lower than the regions on both sides of the sipes. Therefore, when the pneumatic tire receives a frictional force from the road surface in the tangential direction of the tire outer circumference, the narrow region is deformed more than the regions on both sides of the sipe. Therefore, one of the pair of sipes of the block is closed and the other is opened, and the driving performance and the braking performance are improved by the edge effect.

[0004]

However, when the blocks are arranged on the tread of the pneumatic tire so that the narrow areas of the blocks are arranged in a row along the tire width direction, the narrow areas of low rigidity are formed in the tire width direction. Therefore, when the side force acts on the pneumatic tire, the deformation of the narrow region becomes large, and there is a problem that the narrow region is chipped or cracked.

In view of the above facts, the present invention is a pneumatic tire capable of preventing a chip or a crack generated in a narrow region of a block sandwiched by a pair of sipes when the block is provided with a pair of sipes. The purpose is to provide.

[0006]

According to the present invention, there is provided a narrow region sandwiched by a pair of sipes that substantially extend in the tire width direction, and a narrow region located on both sides of the narrow region via the sipes. And a wide area in which the tire circumferential direction average length TS of the narrow area and the tire circumferential average length TL of the wide area are 0.1 ≦ TS / TL ≦ 0.
The pneumatic tire having the relationship of No. 8 is characterized in that a high-rigidity region having higher rigidity than the narrow region is arranged laterally of the narrow region in the tire width direction.

[0007]

According to the present invention, the pneumatic tire is grounded,
When the block receives a frictional force in the tire outer peripheral tangential direction due to driving or braking, the block is deformed, but the tire circumferential average length T in the narrow region of the block sandwiched by sipes.
The relationship between S and the tire circumferential direction average length TL of the wide areas of the blocks located on both sides of the narrow area via the sipes is 0.
Since 1 ≦ TS / TL ≦ 0.8 is set, there is a difference in rigidity between the narrow region and the wide region, and the deformation of the narrow region is larger than that in the wide region. Therefore, in the block that receives the frictional force, one of the two sipes is closed and the other sipes are opened, and the running performance is improved by the edge effect of the tread side corner portion of the narrow area on the opened sipes side. (Driving performance and braking performance) are improved.

Further, in the pneumatic tire of the present invention, since a high rigidity region having a higher rigidity than the narrow region is arranged laterally in the tire width direction in the narrow region, even when an extreme frictional force acts, Since it does not concentrate on one sipe, the sipe does not open excessively and cracks occur at the bottom of the sipe. Furthermore, even if a side force acts and a complicated force mainly composed of a lateral component acts on the narrow region, the amount of deformation is moderated by the high rigidity region and decreases, especially at both ends of the narrow region. The occurrence of cracks is prevented. As described above, according to the present invention, it is possible to effectively prevent the occurrence of cracks in the narrow region and the chipping caused thereby.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, the pneumatic tire 10 to which the present invention is applied has a plurality of blocks 1 on its tread.
The block row 13 composed of 2 is arranged in the tire width direction (arrow B in FIG. 1).
Direction)) is provided in five rows. Each block row 13
The blocks 12 are arranged at predetermined intervals along the tire circumferential direction (direction of arrow A in FIG. 1).

As shown in FIG. 2, the block 12 has a substantially prismatic shape, and the dimension T of the block 12 in the tire circumferential direction (direction of arrow A in FIG. 2) is preferably 15 mm ≦ T ≦ 40 mm.
More preferably, it is set in the range of 20 mm ≦ T ≦ 35 mm. Here, when the tire circumferential dimension T of the block 12 exceeds 40 mm, the ground contact pressure decreases as the tire circumferential length of the block 12 increases, so that it is difficult to expect the edge effect, and the driving It is not preferable because the performance and the braking performance deteriorate. On the other hand, the tire circumferential dimension T is 15
If it is less than mm, the rigidity of the block 12 becomes too small, and as a result, it is difficult to expect the edge effect of the block 12, and the driving performance and the braking performance deteriorate, which is not preferable. In the present embodiment, the dimension W of the block 12 in the tire width direction (direction of arrow B in FIG. 2) is set to 34 mm.

A pair of sipes 14 extending linearly in the tire width direction and parallel to each other are provided at the center of the block 12 in the tire circumferential direction (the sipes referred to herein are preferably 1 mm or less, and more preferably 1 mm or less). Refers to those having a groove width of 0.6 mm or less).
In addition, in this embodiment, the groove width of the sipe 14 is set to 0.5 mm.

Both longitudinal ends of the sipes 14 reach the side wall 12A of the block 12 on the tire width direction side, and the blocks 12 are divided into three regions in the tire circumferential direction by the sipes 14. A region sandwiched by the pair of sipes 14 is a narrow region 16, and a region adjacent to both sides of the narrow region 16 in the tire circumferential direction is a wide region 18 as a high rigidity region.

As shown in FIG. 1, the block 12 is displaced from the block 12 adjacent to the tire width direction side by a predetermined dimension in the tire circumferential direction, and is adjacent to the narrow region 16 on the tire width direction side. The wide area 18 of the block 12 is disposed.

The ratio TS / TL between the width TS of the narrow region 16 and the width TL of the wide region 18 is 0.1 ≦ TS / T.
L ≦ 0.8, preferably 0.2 ≦ TS / TL ≦
It is set to 0.5. Note that the block 12 of this embodiment is
Indicates that the width TL of the wide region 18 in the tire circumferential direction is set to 14 mm, and the size TS of the narrow region 16 in the tire circumferential direction is 5 mm.
It is set to mm and the ratio T with the width TL of the wide area 18 is set.
The S / TL is about 0.36.

Therefore, the rigidity of the narrow region 16 is smaller than the rigidity of the wide regions 18 on both sides. Therefore, as shown in FIG. 3, when the block 12 comes into contact with the road surface 20 during driving or braking and a frictional force in the tire outer peripheral tangential direction (direction of arrow F in FIG. 3) acts on the block 12, the wide area 1
The deformation of No. 8 is small, and the deformation of the narrow region 16 is large.
As a result, the sipe 14 on the arrow F direction side of the two sipes 14 is closed, and the sipe 14 on the opposite side to the arrow F direction side is opened, and the corner portion 16B of the narrow region 16 on the tread surface 16A side.
The edge effect improves the performance on ice.

When the ratio TS / TL between the width TS of the narrow region 16 and the width TL of the wide region 18 exceeds 0.8, the difference in rigidity between the narrow region 16 and the wide region 18 becomes small, and during braking and When driving, the sipe 14 becomes difficult to open and the edge effect cannot be expected, and when it is less than 0.1, the rigidity of the narrow region 16 is excessively reduced and the durability of the narrow region 16 is reduced, which is not preferable.

Further, the pneumatic tire 10 of this embodiment is
Since the narrow regions 16 and the wide regions 18 having higher rigidity than the wide region 18 are alternately arranged in the tire width direction, they are concentrated on one sipe 14 even when an extreme frictional force acts. Therefore, the sipe 14 does not open excessively and the bottom portion 14A of the sipe 14 does not crack. Further, the side force F acts and the narrow region 16
Even if a complicated force having a lateral component as the main component acts, the amount of deformation is moderated and reduced by the wide region 18 having high rigidity, and the occurrence of cracks in the narrow region 16 especially at both ends is prevented. .. As described above, according to the present invention, it is possible to effectively prevent the occurrence of cracks in the narrow region 16 and the resulting chipping.

Next, a second embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 4, in the pneumatic tire 10 of the present embodiment, the block row 13 located at the center in the tire width direction (direction of arrow B in FIG. 4) and the block row 13 located at both ends in the tire width direction. And a sipe-free block 19 as a prismatic high-rigidity region in which no sipe is provided.
A block row 17 including the blocks is arranged, and these blocks without sipes 19 are arranged laterally of the narrow region 16 in the tire width direction. The tire-widthwise dimensions of these blocks without sipes are substantially the same as the tire-widthwise dimensions of the block 12, and the tire circumferential direction (arrow A direction in FIG. 4) is smaller than the tire circumferential dimension of the narrow region 16. It is made longer and has higher rigidity than the narrow region 16.

Therefore, the pneumatic tire 1 of this embodiment
Even at 0, a portion having higher rigidity than the narrow region 16 (the wide region 18 and the sipeless block 19) is disposed on the lateral side of the narrow region 16 in the tire width direction. Similar to the tire 10, even when an extreme frictional force acts, it does not concentrate on one sipe 14, so the sipe 14 does not open excessively and cracks occur at the bottom portion 14A of the sipe 14. .. Further, even if the side force F acts and a complicated force having a lateral component as a main component acts on the narrow region 16, the deformation amount thereof is a region having high rigidity (wide region 18 and sipeless block 19).
Are alleviated and reduced, and the occurrence of cracks in the narrow region 16, especially at both ends, is prevented. in this way,
Also in this embodiment, it is possible to effectively prevent the occurrence of cracks in the narrow region 16 and the chipping caused thereby.

Next, a third embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 5, in the pneumatic tire 10 of this embodiment, a high rigidity region continuous in the tire circumferential direction (direction of arrow A in FIG. 5) is formed in the center of the tire width direction (direction of arrow B in FIG. 5). Ribs 21 are provided. The rib 2
1, short sipe 23 extending from the side surface in the tire width direction toward the tread center is alternately arranged along the tire circumferential direction. The rigidity of the rib 21 in the tire width direction is set to be higher than that of the narrow region 16.

Therefore, the pneumatic tire 1 of this embodiment
Also in 0, since a portion having higher rigidity than the narrow region 16 (the wide region 18 and the rib 21) is arranged laterally of the narrow region 16 in the tire width direction, the pneumatic tire 10 of the first embodiment is provided. Similarly, even when an extreme frictional force acts, it does not concentrate on one sipe 14, so that the sipe 14 does not open excessively and cracks occur at the bottom portion 14A of the sipe 14. Further, even if the side force F acts and a complicated force having a lateral component as a main component acts on the narrow region 16, the amount of deformation is relaxed by the region having high rigidity (the wide region 18 and the rib 21). Therefore, the occurrence of cracks in the narrow region 16 is prevented especially at both ends. As described above, also in this embodiment, it is possible to effectively prevent the occurrence of cracks in the narrow region 16 and the chipping caused thereby.

Next, a fourth embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 6, block 1 of the present embodiment.
2 is the tire width direction of the narrow region 16 (arrow B direction in FIG. 6)
The dimension is slightly shorter than the dimension of the wide region 18 in the tire width direction, and the sipe 14 is slightly inclined with respect to the tire width direction.

Also in this embodiment, the adjacent blocks 1
The two are arranged so as to be offset from each other in the tire circumferential direction, and the wide regions 18 of the adjacent blocks 12 are arranged on the tire width direction side of the narrow region 16.

Therefore, the pneumatic tire 1 of this embodiment
At 0, as with the pneumatic tire 10 of the first embodiment, even when the extreme frictional force acts, one sipe 14
Since it does not concentrate at the bottom, the sipe 14 does not open excessively and the bottom portion 14A of the sipe 14 does not crack. Further, even if the side force F acts and a complicated force having a lateral component as a main component acts on the narrow region 16, the amount of deformation is moderated by the region of high rigidity (wide region 18) and becomes small. The generation of cracks in the narrow region 16 is prevented especially at both ends. For example, narrow area
The longitudinal dimension of 16 is 50 to 95 of the longitudinal dimension of the wide area 18.
When set to%, sipe 14 due to side force input
Occurs at the widthwise end (circumferential main groove opening) of the bottom portion 14A of
The crack which is easy to do
By further reducing the burden on the narrow area 16, the prevention is further enhanced.
You can stop.

As described above, also in the present embodiment, it is possible to effectively prevent the occurrence of cracks in the narrow region 16 and the resulting chipping.

The longitudinal direction of the sipes formed on the block is preferably inclined within the range of 0 ° to 30 ° with respect to the tire width direction.

Further, as shown in FIG. 7, the bottom portion 14A of the sipe 14 may be formed so as to have a substantially circular cross section in which the bottom portion 14A is swollen in a direction away from the other sipe. This prevents stress from being concentrated on the bottom portion 14A when the sipe 14 is opened, and prevents the bottom portion 14A from cracking.

In each of the above embodiments, one pair of sipes is provided for each block. However, the present invention is not limited to this, and two or more pairs of sipes may be provided for each block. Good. Even in this case, a region having higher rigidity than the narrow region on the lateral side of the narrow region in the tire width direction (ribs, blocks without sipes, wide region of block, etc.)
Needless to say, it is provided.

Further, the block 12 has a pair of sipes.
14, the tire of the block 12 as shown in FIG.
A circumferential die extending along the circumferential direction (arrow A direction in FIG. 11).
Even if the blocks 25 are formed on both sides of the block 12 in the tire circumferential direction,
Good. This circumferential sipe 25 is at least the block 1
2 is formed on one side in the tire circumferential direction and is 0 to 4 in the circumferential direction.
It is preferable to incline at 5 ° to prevent skidding
The performance against it is improved. (Test Example) In Table 1 below, Comparative Example Product 1, Comparative Example Product 2,
The pneumatic tires of the comparative example product 3 and the product of the present invention were filled with normal internal pressures, respectively, and these pneumatic tires were mounted on the front wheels of a 10-ton truck with a constant load, and the 10-ton truck was run for 10,000 km. The results of measuring the number of cracks generated in the are shown.

The pneumatic tire of Comparative Example product 1 is shown in FIG.
As shown in FIG. 9, the narrow regions 16 of the block 12 are arranged in a row in the tire width direction, and the pneumatic tire of Comparative Example product 2 has a block row 13 on one side in the tire width direction as shown in FIG. In the other four row blocks 13, the narrow regions 16 of the blocks 12 are arranged in a row in the tire width direction. Further, in the pneumatic tire of Comparative Example product 3, as shown in FIG. 10, the narrow regions 16 of the blocks 12 in the central three-row block row 13 are aligned in the tire width direction, and the block rows 13 on both sides in the tire width direction are arranged. Narrow area 16
Are arranged so as to be displaced in the tire circumferential direction with respect to the central three-row block row 13. The size of each of these test tires is 10.00R20, and the block size and the number of blocks per tire are all the same.

[0035]

[Table 1]

From the test results shown in Table 1, it became clear that the pneumatic tire 10 of the present invention prevents the occurrence of cracks in the narrow region 16.

[0037]

Since the pneumatic tire of the present invention has the above-mentioned structure, when a pair of sipes is provided on the block, it is possible to prevent cracks and cracks occurring in the narrow region of the block sandwiched by the pair of sipes. It has an excellent effect of being able to.

[Brief description of drawings]

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

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

FIG. 3 is a side view seen from the tire width direction showing a state in which a block of the pneumatic radial tire according to the first embodiment of the present invention is deformed by receiving a frictional force from a road surface.

FIG. 4 is a diagram showing a tread pattern of a pneumatic radial tire according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a tread pattern of a pneumatic radial tire according to a third embodiment of the present invention.

FIG. 6 is a diagram showing a tread pattern of a pneumatic radial tire according to a fourth embodiment of the present invention.

FIG. 7 is a side view of a block of a pneumatic radial tire according to another embodiment of the present invention viewed from the tire width direction.

8 is a diagram showing a tread pattern of a pneumatic radial tire according to Comparative Example 1. FIG.

FIG. 9 is a diagram showing a tread pattern of a pneumatic radial tire according to Comparative Example 2.

FIG. 10 is a diagram showing a tread pattern of a pneumatic radial tire according to Comparative Example 3.

FIG. 11 is a pneumatic radial according to another embodiment of the present invention .
It is a development view of a tread showing a block of a tire.

[Explanation of Codes] 10 Pneumatic tire 12 Block 14 Sipe 16 Narrow area 18 Wide area (high rigidity area) 19 Sipes-free block (high rigidity area) 21 Rib (high rigidity area)

[Procedure amendment]

[Submission date] January 7, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 11

[Correction method] Added

[Correction content]

FIG. 11

Claims (1)

[Claims] 1. A block having a narrow region sandwiched by a set of two sipes extending substantially in the tire width direction, and wide regions positioned on both sides of the narrow region with the sipe interposed therebetween. The tire circumferential direction average length TS of the narrow region and the tire circumferential direction average length TL of the wide region are pneumatic tires having a relationship of 0.1 ≦ TS / TL ≦ 0.8. A high-rigidity region having rigidity higher than that of the narrow region is arranged laterally of the narrow region in the tire width direction.