JP6848583B2 - tire - Google Patents

Description

The present invention relates to a tire provided with a plurality of blocks in a tread portion.

For example, a tire intended for traveling on a snowy ice road is provided with a plurality of blocks in a tread portion. A narrow sipe is formed in each block. Such tires increase the shear force of snow columns and the frictional force against snow and ice road surfaces.

In recent years, it has been required to improve the running performance on snow and ice road surfaces. It is conceivable to increase the number of sipes in order to increase the frictional force on ice. However, such a method has a problem that the rigidity of the block is lowered and the steering stability performance is deteriorated.

Japanese Unexamined Patent Publication No. 2012-224245

The present invention has been devised in view of the above circumstances, and provides a tire capable of improving driving performance on snow and ice roads while maintaining steering stability performance based on improving the arrangement of sipes. The main purpose is to do.

The present invention is a tire provided with a plurality of blocks in a tread portion, and at least one of the blocks has a tread surface sandwiched between a first edge and a second edge extending in the tire circumferential direction. A fully open sipe extending from the first edge to the second edge and a fully open sipe extending adjacent to one side of the tire circumferential direction of the full open sipe and extending from the first edge are fully open on the tread. The first semi-open sipe having a break that terminates without reaching both the sipe and the second edge, and the fully open sipe that are located adjacent to the other side of the tire circumferential direction and extend from the second edge. A full open sipe and a second semi-open sipe having a break that terminates without reaching the first edge are provided, and each of the first semi-open sipe and the second semi-open sipe has its respective break. It extends toward the end in a direction approaching a virtual straight line connecting both ends of the full open sipe.

It is desirable that the tire according to the present invention has a zigzag shape in which the fully open sipe has a first top portion and a second top portion protruding toward the one side and the other side in the tire circumferential direction with respect to the virtual straight line.

In the tire according to the present invention, the fully open sipe includes an inclined element that inclines with respect to the virtual straight line and connects the first top and the second top, and the break of the first semi-open sipe. The edges are preferably located within the projected area of the tilting element projected in the tire circumferential direction.

In the tire according to the present invention, it is desirable that the break end of the first semi-open sipe is located at a distance of 2 to 5 mm from the first top portion.

In the tire according to the present invention, the fully open sipe includes an inclined element that inclines with respect to the virtual straight line and connects the first top and the second top, and the interruption of the second semi-open sipe. The edges are preferably located within the projected area of the tilting element projected in the tire circumferential direction.

In the tire according to the present invention, it is desirable that the break end of the second semi-open sipe is located at a distance of 2 to 5 mm from the second top.

In the tire according to the present invention, the fully open sipe includes a second edge side inclined element in which the fully open sipe extends from the first top to the second edge in an inclination opposite to the inclined element, and the first semi-open sipe is a tire. , It is desirable that the tire is tilted in the same direction as the second edge side tilting element.

In the tire according to the present invention, the full open sipe includes a first edge side inclined element in which the fully open sipe extends from the second top to the first edge in an inclination opposite to the inclined element, and the second semi-open sipe is a tire. , It is desirable that the first edge side inclined element is inclined in the same direction.

In the tire according to the present invention, the fully open sipe includes a second edge-side inclined element in which the fully open sipe extends from the first top portion to the second edge in an inclination opposite to the inclined element, and the inclined element and the first one. The angle between the edge-side tilting element is preferably 110 to 130 degrees, and the angle between the tilting element and the second edge-side tilting element is preferably 110 to 130 degrees.

In the tire according to the present invention, the first edge is arranged outside the second edge in the tire axial direction, and the first edge side inclined element is located at the end on the first edge side in the tire axial direction. It is desirable to have an axial portion that extends along.

In the tire according to the present invention, the block includes a first block in which the second edge extends in a zigzag manner and a second block in which the second edge extends smoothly, and the first block is the first semi-open. The angle of the sipe with respect to the tire axis direction is 10 to 30 degrees, the angle of the second semi-open sipe with respect to the tire axis direction is 20 to 40 degrees, and the second block is the tire shaft of the first semi-open sipe. It is desirable that the angle with respect to the direction is 15 to 35 degrees and the angle of the second semi-open sipe with respect to the tire axial direction is 15 to 35 degrees.

In the tire of the present invention, the block has a tread surface sandwiched between a first edge and a second edge extending in the tire circumferential direction. A fully open sipe extending from the first edge to the second edge and a fully open sipe extending adjacent to one side of the full open sipe in the tire circumferential direction and extending from the first edge are fully open on the tread. A first semi-open sipe that terminates without reaching both the sipe and the second edge, and the full open sipe that is located adjacent to the other side of the full open sipe in the tire circumferential direction and extends from the second edge. At least a second semi-open sipe that terminates without reaching the first edge is provided. The full open sipe, the first semi-open sipe, and the second semi-open sipe can exert a large frictional force, so that the snow and ice road performance is improved. Further, the first semi-open sipe and the second semi-open sipe can suppress a decrease in the rigidity of the block while exerting the above-mentioned action.

Each of the first semi-open sipe and the second semi-open sipe extends in a direction approaching a virtual straight line connecting both ends of the full open sipe toward each break. As a result, the rigidity of the block is made uniform, so that cracks originating from each sipe are suppressed. Therefore, since the decrease in the rigidity of the block is suppressed to a small extent, the steering stability performance is further maintained.

Therefore, the tire of the present invention improves the snow and ice road performance while maintaining the steering stability performance.

It is a developed view of the tread part of one Embodiment of this invention. It is a development view of the block of one embodiment. It is a development view of the block of one embodiment. It is a development view of the block of one embodiment. (A) and (b) are plan views of the sipe of another embodiment. (A) and (b) are plan views of the sipe of still another embodiment. It is a development view of the tread part which shows the comparative example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a developed view of a tread portion 2 of a tire 1 showing an embodiment of the present invention. In this embodiment, a pneumatic tire for a passenger car is shown as a preferred embodiment. However, it goes without saying that the present invention can be applied to tires 1 of other categories such as for heavy loads.

As shown in FIG. 1, a plurality of blocks 4 are provided in the tread portion 2 of the present embodiment.

In the present embodiment, the block 4 is sandwiched between the shoulder block 4A arranged on the most tread end Te side, the crown block 4B arranged on the most tire equator C side, and the shoulder block 4A and the crown block 4B. Includes the middle block 4C. In this embodiment, the blocks 4A to 4C are separated from each other in the tire circumferential direction.

The "tread end" Te is a normal load in which a normal load is applied to a tire 1 in a normal state, which is a normal rim and is filled with a normal internal pressure and is in a normal state, and is grounded on a flat surface at a camber angle of 0 degrees. It is defined as the most outer contact position in the tire axial direction under load. In the normal state, the distance between the tread end Te and Te in the tire axial direction is defined as the tread width TW. Unless otherwise specified, the dimensions and the like of each part of the tire 1 are values measured in a normal state.

A "regular rim" is a rim defined for each tire in the standard system including the standard on which the tire is based. For example, "standard rim" for JATMA, "Design Rim" for TRA, and ETRTO. If so, it is "Measuring Rim".

"Regular internal pressure" is the air pressure defined for each tire in the standard system including the standard on which the tire is based. For JATMA, "maximum air pressure", for TRA, the table "TIRE LOAD LIMITS" The maximum value described in "AT VARIOUS COLD INFLATION PRESSURES", or "INFLATION PRESSURE" for ETRTO.

"Regular load" is the load defined for each tire in the standard system including the standard on which the tire is based. For JATMA, "maximum load capacity", for TRA, the table "TIRE LOAD" The maximum value described in "LIMITS AT VARIOUS COLD INFLATION PRESSURES", or "LOAD CAPACITY" for ETRTO.

FIG. 2 is a plan view showing an example of the block 4 of the present embodiment. As shown in FIG. 2, the tread surface 4a of the block 4 is sandwiched between the first edge 5 and the second edge 6 extending in the tire circumferential direction. The tread surface 4a of the present embodiment further includes a third edge 7 extending in the tire axial direction by connecting one end of the first edge 5 and the second edge 6 in the tire circumferential direction, and the first edge 5 and the second edge 6. The other end in the tire circumferential direction is sandwiched between the fourth edges 8 extending in the tire axial direction.

A full open sipe 10, a first semi-open sipe 11, and a second semi-open sipe 12 are provided on the tread surface 4a of the block 4. The full open sipe 10 extends from the first edge 5 to the second edge 6. The first semi-open sipe 11 is arranged adjacent to one side (upper side in the figure) of the full open sipe 10 in the tire circumferential direction and extends from the first edge 5 to reach both the full open sipe 10 and the second edge 6. It has a break 11e that terminates without any interruption. The second semi-open sipe 12 is arranged adjacent to the other side (lower side in the figure) of the full open sipe 10 in the tire circumferential direction and extends from the second edge 6 to reach the full open sipe 10 and the first edge 5. It has a break 12e that terminates without interruption. The full open sipe 10, the first semi-open sipe 11, and the second semi-open sipe 12 exert a large frictional force, so that the snow and ice road performance is improved. Further, since the first semi-open sipe 11 and the second semi-open sipe 12 can suppress the decrease in the rigidity of the block while exerting the above-mentioned action, the decrease in the steering stability performance is suppressed.

As used herein, each "sipe" is defined as a notch with a width of less than 2 mm.

Each of the first semi-open sipe 11 and the second semi-open sipe 12 extends in a direction approaching a virtual straight line 10c connecting both ends 10a and 10b of the full open sipe 10 toward the respective break ends 11e and 12e. As a result, the rigidity of the block is made uniform, so that cracks starting from each sipe 10 to 12 are suppressed. Therefore, since the decrease in the rigidity of the block is suppressed to a small extent, the steering stability performance is further maintained. Therefore, the tire 1 of the present invention improves the snow and ice road performance while maintaining the steering stability performance.

In the present invention, if at least one block 4 is provided with the full open sipe 10, the first semi-open sipe 11, and the second semi-open sipe 12, regardless of the shape of the tread 4a of the block 4, the above will be described. The effect of is demonstrated.

In the present embodiment, the full open sipe 10 is formed in a zigzag shape having a first top portion 15 and a second top portion 16 projecting to the one side and the other side in the tire circumferential direction with respect to the virtual straight line 10c. Since such a full open sipe 10 has a multi-directional edge component, the snow-ice road performance is maintained high.

In the present embodiment, the first top portion 15 and the second top portion 16 are vertices that are most separated from the virtual straight line 10c on the one side and the other side in the tire circumferential direction. As a result, a large edge component can be obtained.

The full open sipe 10 has an inclined element 17, a first edge side inclined element 18, and a second edge side inclined element 19. The tilting element 17 connects between the first top 15 and the second top 16. The first edge side inclined element 18 extends from the second top portion 16 to the first edge 5 at an inclination opposite to that of the inclined element 17. The second edge side inclined element 19 extends from the first top portion 15 to the second edge 6 at an inclination opposite to that of the inclined element 17. In such a fully open sipe 10, since the opening and closing of the sipe is restricted, cracks in the block 4 are suppressed.

In the present embodiment, the tilting element 17 is tilted to one side in the tire axial direction (upward to the left in the figure) and extends linearly. In the present specification, the "straight line" includes a mode in which both ends are connected by a straight line and a mode in which the ends are connected in a smooth arc shape without having a bent portion. The tilting element 17 is not limited to such a mode in which it extends linearly, and may be, for example, a mode in which it has a bent portion and is tilted to one side in the tire axial direction at different tilt angles.

In the present embodiment, the first edge side inclined element 18 connects the main portion 18a which is inclined in the direction opposite to the inclined element 17 from the second top portion 16 and the main portion 18a and one end 10a and extends along the tire axial direction. Includes the axial portion 18b. In such a first edge side inclined element 18, the axial direction portion 18b exerts a large frictional force against straight running, and the main portion 18a has a tire circumferential component, so that the frictional force is exerted against turning running. Make it work. In the present specification, the "axial portion extending along the tire axial direction" includes, of course, an embodiment extending parallel to the tire axial direction, and other inclined elements in which the axial portions are connected (mainly in the present embodiment). Part) includes a mode in which the tire extends at a smaller angle with respect to the tire axial direction. It is desirable that the axial portion extends at an angle α of 5 degrees or less with respect to the tire axial direction, for example.

The first edge side inclined element 18 is not limited to such a mode, and may be, for example, a mode extending linearly between the second top portion 16 and one end 10a (not shown).

In the present embodiment, the second edge side inclined element 19 extends linearly between the first top portion 15 and the other end 10b. The second edge-side inclined element 19 is not limited to such an embodiment, and is configured to include, for example, a main portion 19a and an axial direction portion 19b, similarly to the first edge-side inclined element 18. It may be used (shown in FIG. 4).

The angle θ1 between the tilting element 17 and the first edge-side tilting element 18 is preferably 110 to 130 degrees. Further, the angle θ2 between the inclined element 17 and the second edge side inclined element 19 is preferably 110 to 130 degrees. When the angles θ1 and θ2 are less than 110 degrees, the rigidity becomes small between the inclined element 17 and the first edge side inclined element 18, or between the inclined element 17 and the second edge side inclined element 19. Steering stability performance may deteriorate. When the angles θ1 and θ2 exceed 130 degrees, the tilting element 17 and the first edge-side tilting element 18 or the tilting element 17 and the second edge-side tilting element 19 approach one straight line, so that the sipes It may not be possible to suppress the opening and closing of. In the present specification, when the edge-side inclined elements 18 and 19 include an axial portion, the angles θ1 and θ2 are measured at an angle between the main portions 18a and 19a and the inclined element 17.

FIG. 3 is a plan view showing an example of the block 4 of the present embodiment. As shown in FIG. 3, the first semi-open sipe 11 is inclined in the same direction as the second edge side inclined element 19 in the present embodiment. As a result, the second edge side inclined element 19 and the first semi-open sipe 11 exert a large frictional force in the same direction, so that the snow and ice road performance is enhanced.

In the present embodiment, the first semi-open sipe 11 connects the main portion 11a extending from the interrupted end 11e toward the first edge 5 side, the main portion 11a and one end 11i on the first edge 5 side, and is in the tire axial direction. Includes an axial portion 11b extending along. The first semi-open sipe 11 is not limited to such a mode, and may be, for example, a mode in which the interrupted end 11e and one end 11i are connected in a straight line (not shown).

In the present embodiment, the break end 11e of the first semi-open sipe 11 is located in the projected inner region 17A in which the inclined element 17 is projected in the tire circumferential direction. Since such a first semi-open sipe 11 has a large edge component, it exhibits excellent snow and ice road performance. In FIG. 3, the projected area 17A of the first semi-open sipe 11 is indicated by a hatch.

In order to effectively exert the above-mentioned action, it is desirable that the break end 11e of the first semi-open sipe 11 is located at a distance La of 5 mm or less from the first top portion 15. If the distance La between the break end 11e of the first semi-open sipe 11 and the first top portion 15 is less than 2 mm, the rigidity of the block 4 becomes excessively small, and the break end 11e or the first top portion 15 is used as the starting point. There is a risk that cracks will easily occur. Therefore, the distance La is preferably 2 mm or more.

The first semi-open sipe 11 is inclined in the same direction as the third edge 7. As a result, the rigidity step in the tire circumferential direction of the block 4 between the first semi-open sipe 11 and the second edge side inclined element 19 and the third edge 7 is kept small.

In the present embodiment, the second semi-open sipe 12 is inclined in the same direction as the first edge side inclined element 18. As a result, a large frictional force is exerted between the first edge side inclined element 18 and the second semi-open sipe 12, so that the snow and ice road performance is enhanced.

In the present embodiment, the second semi-open sipe 12 extends linearly between the interrupted end 12e and the other end 12i on the second edge 6 side. The second semi-open sipe 12 is not limited to such an embodiment. The second semi-open sipe 12 is, for example, an axial portion 12b that connects the main portion 12a extending from the interrupted end 12e toward the second edge 6 side, the main portion 12a and the other end 12i, and extends along the tire axial direction. And may be configured to include (shown in FIG. 4).

The break 12e of the second semi-open sipe 12 is located in the projection area 17A in the present embodiment. Since such a second semi-open sipe 12 has a large edge component, the snow-ice road performance is improved.

The break end 12e of the second semi-open sipe 12 is located at a distance La of 2 to 5 mm from the second top 16 for the same reason as the arrangement position of the break end 11e of the first semi-open sipe 11. desirable.

The second semi-open sipe 12 is inclined in the same direction as the fourth edge 8. As a result, the rigidity step in the tire circumferential direction of the block 4 between the second semi-open sipe 12 and the first edge side inclined element 18 and the fourth edge 8 is kept small.

In the present embodiment, the first edge 5 is provided outside the tire axial direction with respect to the second edge 6. The first edge-side inclined element 18 and the first semi-open sipe 11 have axial portions 18b and 11b, respectively. As a result, the tire axial rigidity of the block 4 on the first edge 5 side on which a large lateral force acts is maintained to be large, so that cracks in the block are suppressed.

It is desirable that two or more of the first semi-open sipe 11, the second semi-open sipe 12, the first edge-side inclined element 18, and the second edge-side inclined element 19 have axial portions. As a result, the stability during straight running on snow and ice roads is highly improved.

In order to effectively exert the above-mentioned action, it is desirable that the depth of each sipe 10 to 12 is 70% to 90% of the block height of the block 4.

FIG. 4 is a development view showing an embodiment of the block 4. As shown in FIG. 4, the block 4 includes the first block 20 and the second block 21 in this embodiment. In the present embodiment, the first block 20 and the second block 21 are alternately arranged in the tire circumferential direction. The first block 20 extends in a zigzag shape in which the second edge 6 has a bent portion 22 at the central portion 6a in the tire circumferential direction. In the present embodiment, the second edge 6 of the first block 20 is provided with one bent portion 22a that is convex outward in the tire axial direction and one bent portion 22b that is convex inward in the tire axial direction at the central portion 6a. Has been done. In the second block 21, the second edge 6 is continuously inclined to one side in the tire axial direction at the central portion 6a in the tire circumferential direction and extends smoothly. In the present specification, the "central portion in the tire circumferential direction" refers to a tire circumference of 30% to 70% of the tire circumferential length Lb of the second edge 6 from any one end to the other end of the second edge 6. Refers to the directional area.

Although not particularly limited, in the present embodiment, the first edge 5 of the first block 20 and the second block 21 has a bent portion 22a that is convex inward in the tire axial direction and an outer side in the tire axial direction in the central portion 5a. Each of the bent portions 22b having a convex shape is provided.

As described above, the shape of the second edge 6 is different between the first block 20 and the second block 21, and the rigidity of the first block 20 on the second edge 6 side is the second edge 6 of the second block 21. Since it is smaller than the rigidity of the side, by specifying the sipe angle, sipe length ratio, and block tire axial width ratio as follows, each block 20 while increasing the frictional force on ice, The rigidity of 21 can be made uniform.

In the first block 20 of the present embodiment, the second semi-open sipe 12 and the second edge side inclined element 19 extend linearly. In the second block 21 of the present embodiment, the second semi-open sipe 12 and the second edge side inclined element 19 have main portions 12a and 19a and axial portions 12b and 19b, respectively.

In the first block 20, the angle θ3 of the first semi-open sipe 11 with respect to the tire axial direction is preferably 10 to 30 degrees. Further, in the first block 20, the angle θ4 of the second semi-open sipe 12 with respect to the tire axial direction is preferably 20 to 40 degrees. As a result, the snow and ice road performance is effectively exhibited.

In the first block 20, the ratio (L2 / L1) of the length L1 of the main portion 11a of the first semi-open sipe 11 to the length L2 of the second semi-open sipe 12 is, for example, 1.1 to 1.2. It is desirable to have it.

In the second block 21, the angle θ5 of the first semi-open sipe 11 with respect to the tire axial direction is preferably 15 to 35 degrees. Further, in the second block 21, the angle θ6 of the second semi-open sipe 12 with respect to the tire axial direction is preferably 15 to 35 degrees.

In the second block 21, the ratio (L4 / L3) of the length L3 of the main portion 11a of the first semi-open sipe 11 to the length L4 of the main portion 12a of the second semi-open sipe 12 is, for example, 0.75-. It is preferably 0.85.

It is desirable that the tire axial width Wb of the second block 21 is larger than the tire axial width Wa of the first block 20 in order to improve the snow and ice road performance while suppressing the reduction of the steering stability performance. More specifically, it is more desirable that the tire axial width Wb of the second block 21 exceeds 1.0 times and 1.1 times or less the tire axial width Wa of the first block 20.

As shown in FIG. 1, in the present embodiment, such a full open sipe 10, a first semi-open sipe 11, and a second semi-open sipe 12 are formed on all the middle blocks 4C arranged in the tire circumferential direction. Has been done. The middle block 4C is a block 4 in which a ground contact pressure due to straight running and a lateral force due to turning running act greatly. Therefore, by providing each of the sipes 10 to 12 in the middle block 4C, the running performance on the snow and ice road surface is improved in both the turning running and the straight running.

Needless to say, the sipes 10 to 12 of the present invention are not limited to those arranged in the middle block 4C, and may be provided in the crown block 4B or the shoulder block 4A.

A lateral groove 30 is formed between the first block 20 and the second block 21. The lateral groove 30 of the present embodiment is provided with a tie bar 31 having a raised groove bottom 30s. As a result, the deformation of the block 4 during traveling is restricted, so that cracks in the block are suppressed. The tie bar 31 of the present embodiment extends from the inner end of the block 4 in the tire axial direction to the outer side in the tire axial direction.

In the present embodiment, the tie bar 31 is provided with a sipe 32 on the outer surface 31a in the radial direction of the tire. The sipe 32 extends linearly along the groove center line 30c of the lateral groove 30. Both ends of the sipe 32 are terminated within the outer surface 31a in the present embodiment. Such a sipe 32 effectively reduces the rigidity of the tie bar 31 and smoothly discharges the snow in the lateral groove 30 to improve the snow and ice road performance.

FIG. 5A shows another embodiment of the sipe that has the same effect as the present invention. The same components as the sipes of the present embodiment are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, the first semi-open sipe 11A and the second semi-open sipe 12A are arranged facing each other with the inclined element 17 sandwiched so as to form one smooth virtual sipe.

FIG. 5B shows yet another embodiment of the sipe that has the same effect as the present invention. The same components as the sipes of the present embodiment are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, the full open sipe 10B includes an inclined element 17B extending along the tire circumferential direction, a first edge side inclined element 18B extending along the tire axial direction, and a second edge side extending along the tire axial direction. Includes tilt element 19B. The first semi-open sipe 11B extends along the tire axial direction and is arranged so as to form one smooth sipe with the second edge side inclined element 19B. The second semi-open sipe 12B extends along the tire axial direction and is arranged so as to form one smooth virtual sipe with the first edge side inclined element 18B.

FIG. 6A shows yet another embodiment of the sipe that has the same effect as the present invention. The same components as the sipes of the present embodiment are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, the full open sipe 10C is inclined from the first edge 5 to the second edge 6 on one side (downward to the right in the figure) with respect to the tire axial direction. The first edge side tilting element 18C and the second edge side tilting element 19C are tilted at a smaller angle with respect to the tire axial direction than the tilting element 17C. The first semi-open sipe 11C extends at an inclination opposite to that of the full open sipe 10 and terminates at a distance La of 2 to 5 mm from the first top portion 15. The second semi-open sipe 12C extends at an inclination opposite to that of the full open sipe 10 and terminates at a distance La of 2 to 5 mm from the second top 16.

FIG. 6B shows yet another embodiment of the sipe that has the same effect as the present invention. The same components as the sipes of the present embodiment are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, the full open sipe 10D extends linearly from the first edge 5 to the second edge 6. The first semi-open sipe 11D and the second semi-open sipe 12D are arranged so as to form one smooth virtual sipe with the full open sipe 10D interposed therebetween.

Although the embodiments of the present invention have been described in detail above, it goes without saying that the present invention is not limited to the exemplary embodiments and can be modified into various embodiments.

A size 265 / 60R18 tire having the basic pattern shown in FIG. 1 was prototyped based on the specifications shown in Table 1, and the snow and ice road performance and steering stability performance of each test tire were tested. The main common specifications and test methods for each sample tire are as follows.
Middle block height: 10.5mm

<Snow and ice road performance / steering stability performance>
Each sample tire was mounted on all wheels of a four-wheel drive vehicle with a displacement of 3600 cc under the following conditions. Then, the test driver ran the test course on the snow-ice road surface and the dry asphalt road surface, and the traction, the running stability, and the running characteristics related to the steerability at this time were evaluated by the sensuality of the test driver. The result is displayed with a score of 100 in Comparative Example 1. The larger the number, the better.
Rim: 18 x 7.5J
Internal pressure: 240kPa (all wheels)
The test results and the like are shown in Table 1.

As a result of the test, it was confirmed that the tires of the examples had improved snow and ice road performance while suppressing a large reduction in steering stability performance as compared with the tires of the comparative examples.

1 Tire 4a Tread 5 1st edge 6 2nd edge 10 Full open sipe 11 1st semi-open sipe 11e 1st semi-open sipe break 12 2nd semi-open sipe 12e 2nd semi-open sipe break 10c Virtual straight line

Claims (12)

A tire with multiple blocks on the tread
At least one of the blocks has a tread surface sandwiched between a first edge and a second edge extending in the tire circumferential direction.
On the tread, a fully open sipe extending from the first edge to the second edge,
A first semi-open sipe that is located adjacent to one side of the full open sipe in the tire circumferential direction and has a break that extends from the first edge and terminates without reaching both the full open sipe and the second edge. When,
A second semi-open sipe located adjacent to the other side of the full open sipe in the tire circumferential direction and having a break extending from the second edge and terminating without reaching the first edge. Is provided at least
Each of the first semi-open sipe and the second semi-open sipe extends in a direction approaching a virtual straight line connecting both ends of the full open sipe toward the respective breaks .
The fully open sipe has a zigzag shape having a first top portion and a second top portion protruding toward the one side and the other side in the tire circumferential direction with respect to the virtual straight line.
The fully open sipe includes a tilting element that tilts relative to the virtual straight line and connects the first top and the second top.
The break end of the first semi-open sipe is a tire located within a projection region in which the inclined element is projected in the tire circumferential direction. A tire with multiple blocks on the tread
At least one of the blocks has a tread surface sandwiched between a first edge and a second edge extending in the tire circumferential direction.
On the tread, a fully open sipe extending from the first edge to the second edge,
A first semi-open sipe that is located adjacent to one side of the full open sipe in the tire circumferential direction and has a break that extends from the first edge and terminates without reaching both the full open sipe and the second edge. When,
A second semi-open sipe located adjacent to the other side of the full open sipe in the tire circumferential direction and having a break extending from the second edge and terminating without reaching the first edge. Is provided at least
Each of the first semi-open sipe and the second semi-open sipe extends in a direction approaching a virtual straight line connecting both ends of the full open sipe toward the respective breaks.
The fully open sipe has a zigzag shape having a first top portion and a second top portion protruding toward the one side and the other side in the tire circumferential direction with respect to the virtual straight line.
The fully open sipe includes a tilting element that tilts relative to the virtual straight line and connects the first top and the second top.
The break end of the second semi-open sipe is a tire located within a projection region in which the inclined element is projected in the tire circumferential direction. A tire with multiple blocks on the tread
At least one of the blocks has a tread surface sandwiched between a first edge and a second edge extending in the tire circumferential direction.
On the tread, a fully open sipe extending from the first edge to the second edge,
A first semi-open sipe that is located adjacent to one side of the full open sipe in the tire circumferential direction and has a break that extends from the first edge and terminates without reaching both the full open sipe and the second edge. When,
A second semi-open sipe located adjacent to the other side of the full open sipe in the tire circumferential direction and having a break extending from the second edge and terminating without reaching the first edge. Is provided at least
Each of the first semi-open sipe and the second semi-open sipe extends in a direction approaching a virtual straight line connecting both ends of the full open sipe toward each of the breaks.
The block includes a first block in which the second edge extends in a zigzag manner and a second block in which the second edge extends smoothly.
The first block has an angle of 10 to 30 degrees with respect to the tire axial direction of the first semi-open sipe, and an angle of 20 to 40 degrees with respect to the tire axial direction of the second semi-open sipe.
The second block is a tire having an angle of the first semi-open sipe with respect to the tire axial direction of 15 to 35 degrees and an angle of the second semi-open sipe with respect to the tire axial direction of 15 to 35 degrees. The tire according to claim 3 , wherein the fully open sipe has a first top portion and a second top portion protruding toward the one side and the other side in the tire circumferential direction with respect to the virtual straight line. The fully open sipe includes a tilting element that tilts relative to the virtual straight line and connects the first top and the second top.
The tire according to claim 2 or 4, wherein the break end of the first semi-open sipe is located in a projection region in which the inclined element is projected in the tire circumferential direction. The tire according to claim 1 or 5, wherein the break of the first semi-open sipe is located 2 to 5 mm apart from the first top. The fully open sipe includes a tilting element that tilts relative to the virtual straight line and connects the first top and the second top.
The tire according to any one of claims 1, 5 and 6, wherein the break end of the second semi-open sipe is located in a projection region in which the inclined element is projected in the tire circumferential direction. The tire according to claim 2 or 7, wherein the break end of the second semi-open sipe is located at a distance of 2 to 5 mm from the second top. The fully open sipe includes a second edge-side tilting element extending from the first apex to the second edge in a tilt opposite to that of the tilting element.
The tire according to any one of claims 1, 5 to 8, wherein the first semi-open sipe is inclined in the same direction as the second edge side inclined element. The fully open sipe includes a first edge-side tilting element extending from the second apex to the first edge in a tilt opposite to that of the tilting element.
The tire according to any one of claims 1, 5 to 9, wherein the second semi-open sipe is inclined in the same direction as the first edge side inclined element. The fully open sipe includes a second edge-side tilting element extending from the first apex to the second edge in a tilt opposite to that of the tilting element.
The angle between the tilting element and the first edge side tilting element is 110 to 130 degrees.
The tire according to claim 10, wherein the angle between the inclined element and the second edge side inclined element is 110 to 130 degrees. The first edge is arranged outside the tire axial direction with respect to the second edge.
The tire according to claim 11, wherein the first edge side inclined element has an axial portion extending along the tire axial direction at the end portion on the first edge side.

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