JP5873538B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire having excellent performance on snow.

  Generally, tires excellent in braking performance (snow braking performance), traction performance (snow traction performance) and turning performance (snow turning performance) are desired as pneumatic tires suitable for snowy roads including snowy roads. .

  Here, usually, the braking performance, traction performance, turning performance, etc. of the tire are affected by the friction characteristics of the tire. Therefore, in order to improve the tire's snow braking performance, snow traction performance and snow turning performance, it is necessary to improve the tire friction characteristics on the snowy road.

  As one means for improving the friction characteristics of the tire on a snowy road, it is formed in a groove disposed in the tread portion by improving the force with which the tire grips and solidifies the snow during rolling of the tire. It is known to increase the shear resistance of a snow column (that is, increase the shear force of the snow column). As another means of improving the friction characteristics of tires on snowy roads, it is known to secure the contact area of the tire and to enhance the scratching effect of the road surface by the edge of the block and the edge of the sipe formed in the tread part. It has been.

However, a rectangular block is defined by forming a plurality of main grooves extending along the tire circumferential direction and a plurality of lateral grooves extending along the tire width direction on the tread portion tread surface, and sipes are formed on the blocks. In the conventional pneumatic tire formed, it was not possible to improve the snow column shear force, ensure the contact area, and improve the scratching effect on the road surface.
That is, in the conventional pneumatic tire described above, when the groove depth of the lateral groove is increased in order to increase the snow column shear force, the rigidity of the block in the circumferential direction of the tire decreases, and the angle of collapse of the block at the time of ground contact increases. As a result, the ground contact area cannot be secured. Also, increasing the number of grooves and sipes formed on the tread surface to increase the scratching effect on the road surface due to block edges and sipe edges will reduce the rigidity of the block and increase the tilt angle of the block when touching. As a result, the ground contact area cannot be secured.
On the other hand, in order to prevent a decrease in the rigidity of the block and secure a ground contact area, a rib-like land portion is formed on the tread portion tread instead of the block, and the density of sipes is suppressed within a predetermined range. (For example, refer to Patent Document 1), the snow column shear force and the scratching effect on the road surface cannot be enhanced.

JP 2001-71713 A

Therefore, the present inventor has confirmed that the friction characteristics of the tire on a snowy road by arranging all of the contact area of the tire, the improvement of the scratching effect of the road surface by the edge, and the improvement of the snow column shear force at a high level. In order to provide a pneumatic tire that is superior in snow performance such as snow braking performance, snow traction performance and snow turning performance, the present inventors have conducted intensive studies.
The present inventor has provided a pneumatic tire in which a main groove extending in the tire circumferential direction and a lateral groove extending in the tire width direction are arranged on the tread portion tread surface to define a plurality of blocks. One end is opened in the lateral groove located at one side in the tire circumferential direction, one end is opened in the lateral groove located at the other side in the tire circumferential direction of the block, and the other notch is blocked at the other end. By forming the second notch groove that terminates in the inside and the connecting narrow groove that connects the first notch groove and the second notch groove, the contact area of the tire is ensured and the road surface is scratched by the edge. It has been found that the improvement and the improvement of the snow column shear force can all be arranged at a high level.

  However, in the pneumatic tire in which the block is formed with the sipe, the first notch groove, the second notch groove, and the connecting narrow groove, the friction characteristics on the snowy road are further improved to further improve the performance on snow. There was still room for improvement.

  In view of this, the present invention provides friction on the snowy road of the tire by ensuring that the contact area of the tire, the improvement of the scratching effect of the road surface by the edge, and the improvement of the snow column shearing force are juxtaposed at a sufficiently high level. An object of the present invention is to provide a pneumatic tire having sufficiently enhanced characteristics and excellent performance on snow.

An object of the present invention is to advantageously solve the above-described problems, and a pneumatic tire according to the present invention has a tire extending in the tire circumferential direction on at least a part of a tread portion tread located between both tread ends. A plurality of main grooves, and a plurality of transverse grooves extending in the tire width direction between the main grooves and / or between the main grooves and the tread ends, to form a block row composed of a plurality of blocks, And a pneumatic tire comprising at least one sipe disposed on the block, wherein one end is opened in a lateral groove located on one side in the tire circumferential direction of the block, and the other end terminates in the block. One notch groove, a second notch groove having one end opened in the transverse groove located on the other side in the tire circumferential direction of the block, and the other end terminating in the block, the first notch groove and the second notch The first notch is connected to the groove A groove and a connecting narrow groove having a groove width narrower than that of the second notch groove are formed in the block, and the rigidity of the block has a rubber composition used for the block and a density of sipes formed on the block. Is changed from the opening side of the first notch groove toward the terminal side of the first notch groove, and second from the opening side of the second notch groove. It increases toward the terminal side of a notch groove. In this way, if the first notch groove and the second notch groove whose one end opens into the transverse groove and the other end terminates in the block are formed, the transverse groove, particularly the transverse groove, the first notch groove or the second notch. It is possible to improve the force of stepping and solidifying the snow at the portion where the notch groove intersects, and to increase the snow column shear force. Further, if the first notch groove and the second notch groove are terminated in the block, and the first notch groove and the second notch groove are connected by the connecting narrow groove, the rigidity (bending rigidity) of the block is achieved. The edge component, in particular, the edge component extending along the tire circumferential direction (hereinafter referred to as “tire circumferential edge component”) can be secured while suppressing the reduction of the contact area and the contact area. Furthermore, if the rigidity of the block, in particular the bending rigidity, is increased from the opening side of the first notch groove and the second notch groove toward the terminal end side, snow in the lateral groove is suppressed while suppressing the reduction of the contact area. The gripping force can be improved to further increase the snow column shearing force, and the effect of scratching the road surface by the edge can be improved. Therefore, according to this pneumatic tire, all of the securing of the contact area of the tire, the improvement of the scratching effect of the road surface by the edge, and the improvement of the snow column shear force are arranged side by side in a sufficiently high dimension, Snow performance such as snow traction performance and snow turning performance can be improved. In the present invention, “extending in the tire circumferential direction” means extending in the tire circumferential direction, and “extending in the tire circumferential direction” is inclined with respect to a direction parallel to the tire circumferential direction. The case of extending is also included. Further, “extending in the tire width direction” means extending in the tire width direction, and “extending in the tire width direction” includes a case of extending in a direction parallel to the tire width direction. It is .

Here, the pneumatic tire of the present invention, the density of arrangement of the previous SL sipe decreases from the opening side of the first notched groove toward the terminal end side of the first notched groove, and said second switching It is preferable to decrease from the opening side of the notch groove toward the terminal end side of the second notch groove.

  In the pneumatic tire of the present invention, it is preferable that the block has a width direction sipe that intersects the connecting narrow groove and extends in the tire width direction. If a sipe in the width direction is formed in the block, an edge component extending in the tire width direction (hereinafter referred to as “tire width direction edge component”) can be secured, and snow braking performance and snow traction performance can be improved. This is because the drainage performance can be secured. Also, if the width direction sipe intersects the connecting narrow groove, the rigidity of the block is greatly reduced and the ground contact area is reduced compared to the case where the width direction sipe intersects the first notch groove and the second notch groove. This is because the decrease can be suppressed.

Further, in the pneumatic tire according to the present invention, the first notch groove and the second notch groove extend in the same direction with respect to the tire circumferential direction, and the connecting narrow groove has a tire circumferential direction. On the other hand, it is preferable that the first notch groove and the second notch groove are inclined and extended to the opposite side. If the inclination direction of the first notch groove and the second notch groove is different from the inclination direction of the connection narrow groove, and the first notch groove, the connection narrow groove, and the second notch groove are arranged in a zigzag shape, This is because the edge component in the tire width direction can be ensured, and snow braking performance and snow traction performance can be improved.
In the present invention, the “groove extending direction” refers to the center of the groove width when grooves such as the first notch groove, the second notch groove, and the connecting narrow groove extend linearly. The direction in which the line extends is indicated. When the groove is bent and extended, the direction in which the amplitude center line of the groove extends is indicated.

Further, the pneumatic tire of the present invention has a land portion row adjacent to the block row across the main groove on the tread portion tread surface, and is positioned on the extending direction line of the lateral groove of the land portion row. It is preferable that an extending lateral groove having one end opened in the main groove and the other end terminating in the land portion row is formed in the portion to be formed. By forming a stretched lateral groove, it is possible to improve the force of stepping and solidifying snow at the intersection of the lateral groove and the main groove, and to increase the snow column shear force, so it is possible to improve snow braking performance and snow traction performance. Because. Further, if the extending transverse groove is terminated in the land portion row, it is possible to suppress a decrease in rigidity of the land portion row and to suppress a decrease in steering stability.
In the present invention, the “land portion row” may be a block land portion row made up of a plurality of blocks, or may be a rib-like land portion row extending continuously in the tire circumferential direction. good. In the present invention, the `` lateral groove extending direction line '' refers to the groove width center line of the lateral groove when the lateral groove extends linearly, and when the lateral groove is bent and extended, Refers to the amplitude center line of the transverse groove.

  Further, in the pneumatic tire according to the present invention, the first notch groove extends in a direction orthogonal to a lateral groove located at one of the tire circumferential directions of the block, and the second notch groove is the tire of the block. It is preferable to extend in a direction perpendicular to the lateral groove located on the other circumferential side. If the first notch groove, the second notch groove and the transverse groove are orthogonal to each other, the snow column shear force at the portion where the transverse groove and the first notch groove or the second notch groove intersect with each other is further increased. This is because the braking performance and snow traction performance can be further improved.

  In the pneumatic tire of the present invention, the tread portion tread has a shape from the tire equator to the tread end located on one side in the tire width direction and a shape from the tire equator to the tread end located on the other side in the tire width direction. Differently, the block is preferably formed on one side in the tire width direction from the tire equator. If the pattern shape of the tread part tread is asymmetric across the tire equator and the above-mentioned block that can improve the performance on snow is formed on one side in the tire width direction, the pattern shape that can improve other performance (for example, performance on ice) This is because it is formed on the other side in the tire width direction so that the performance on snow and the other performance can be balanced.

  According to the pneumatic tire of the present invention, all of the securing of the tire contact area, the improvement of the scratching effect of the road surface by the edge, and the improvement of the snow column shear force are arranged side by side with a sufficiently high dimension, and the tire on the snowy road It is possible to improve the on-snow performance of the tire by sufficiently increasing the friction characteristics.

FIG. 3 is a development view of a part of a tread portion of a typical pneumatic tire according to the present invention. It is sectional drawing which follows the II line | wire of FIG.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a development view of a part of the tread portion of an example of the pneumatic tire of the present invention. The pneumatic tire shown in FIG. 1 is not particularly limited and can be suitably used as a studless tire.

  Here, as shown in FIG. 1, in the pneumatic tire of this example, the tread portion tread surface 100 located between the tread ends TE has an asymmetric shape with the tire equator C as the center. That is, in this example pneumatic tire, the pattern shape from the tire equator C to the tread end TE located on one side in the tire width direction (right side in FIG. 1), and the other in the tire width direction from the tire equator C (left side in FIG. 1). The pattern shape up to the tread end TE located at is different.

Specifically, one first main groove 1 extending in the tire circumferential direction between the tire equator C and the tread end TE located on one side in the tire width direction (right side in FIG. 1) of the tread portion tread 100. Between the first main groove 1 and the second main groove 2 that is located on the tread end TE side and extends in the tire circumferential direction, and between the first main groove 1 and the second main groove 2. Are formed, and a plurality of lug grooves 6 extending in the tire width direction are formed between the second main groove 2 and the tread end TE.
The first main groove 1 is bent and extended in a zigzag shape in the tire circumferential direction. Moreover, the 2nd main groove 2 has the expansion part 2A extended along a tire circumferential direction, and a groove width expanded at a predetermined space | interval in a tire circumferential direction. Further, the lateral grooves 5 are inclined at a predetermined angle with respect to the tire width direction (upward to the left in FIG. 1), and the lug grooves 6 are also formed at a predetermined angle with respect to the tire width direction. It extends at an angle (upward to the left in FIG. 1). Incidentally, the groove width of the lateral groove 5 gradually decreases from the second main groove 2 side toward the first main groove 1 side.

The tread portion tread 100 is partitioned by the first main groove 1, the second main groove 2 and the lateral groove 5 from the tire equator C to the tread end TE located on one side in the tire width direction (right side in FIG. 1). A block row 10 including a plurality of blocks 11 to be formed is formed. Further, a shoulder block row 20 including a plurality of shoulder blocks 21 defined by the second main groove 2, the lug groove 6 and the tread end TE is formed on the tread end TE side with respect to the block row 10.
In the plan view of the tread portion tread 100, the block 11 and the shoulder block 21 have a substantially parallelogram shape.

In addition, between the tire equator C and the tread end TE located on the other side in the tire width direction (left side in FIG. 1) of the tread portion tread 100, there is one circumferential thick groove 3 extending in the tire circumferential direction, One circumferential narrow groove 4 that is positioned on the tread end TE side relative to the circumferential thick groove 3 and extends in the tire circumferential direction, and a plurality that extends in the tire width direction between the circumferential thick groove 3 and the circumferential narrow groove 4 A plurality of bent lateral grooves 8 and a plurality of lug grooves 9 extending in the tire width direction are formed between the circumferential narrow grooves 4 and the tread ends TE.
The circumferential thick groove 3 extends along the tire circumferential direction. The circumferential narrow groove 4 has a narrower groove width than the circumferential thick groove 3 and extends linearly along the tire circumferential direction. Further, the bent lateral groove 8 extends in the tire width direction with one bending point that has a convex shape on one side in the tire circumferential direction (downward in FIG. 1). Further, the lug groove 9 extends at a predetermined angle with respect to the tire width direction (upwardly in FIG. 1).

Then, between the tire equator C and the tread end TE located on the other side in the tire width direction (left side in FIG. 1) of the tread portion tread 100 is formed by the circumferential thick groove 3, the circumferential narrow groove 4, and the bent lateral groove 8. An arrow feather block row 40 including a plurality of arrow feather blocks 41 that are partitioned is formed. Further, on the tread end TE side with respect to the arrow feather block row 40, a shoulder block row 50 including a plurality of shoulder blocks 51 defined by the circumferential narrow groove 4, the lug groove 9, and the tread end TE is formed. Yes.
In the plan view of the tread portion tread surface 100, the arrow feather block 41 has an arrow feather shape in which the position of the apex is offset to one side in the tire width direction (right side in FIG. 1). The shoulder block 51 has a substantially parallelogram shape.

Further, a central lateral groove 7 extending in the tire width direction is formed between the first main groove 1 and the circumferential thick groove 3 at the central portion of the tread portion tread surface 100 (near the tire equator C).
The central lateral groove 7 is bent in a zigzag shape, and is inclined at a predetermined angle with respect to the tire width direction (upward to the right in FIG. 1).

A central block row composed of a plurality of central blocks 31 defined by the first main groove 1, the circumferential thick groove 3 and the central lateral groove 7 is formed in the central portion of the tread portion tread surface 100 (near the tire equator C). (Land part row) 30 is formed.
In the plan view of the tread portion tread surface 100, the central block 31 has a substantially trapezoidal shape.

  Here, a block 11 constituting the block row 10 located between the first main groove 1 and the second main groove 2 includes a large number (one or more) of sipes 12 extending in the tire width direction, One end of the lateral groove 5 located on one side in the tire circumferential direction (the lower side in FIG. 1) is open, and the other end terminates in the block 11, and the other in the tire circumferential direction of the block 11 (in FIG. 1). A second notch groove 14 having one end opened in the lateral groove 5 positioned on the upper side and the other end terminating in the block 11, and a connecting narrow groove connecting the first notch groove 13 and the second notch groove 14. 15 is formed. Further, the block 11 includes a third notch groove 17 having one end opened in the second main groove 2 located on one side in the tire width direction of the block 11 (right side in FIG. 1) and the other end terminating in the block 11. A fourth cutout groove 18 having one end opened in the first main groove 1 located on the other side in the tire width direction of the block 11 (left side in FIG. 1) and the other end terminating in the block 11, and a third cutout groove A width-direction sipe 16 that extends in the tire width direction intersecting with the connecting narrow groove 15 is formed between 17 and the fourth notch groove 18.

In the block 11, the rigidity (particularly bending rigidity) of the block increases from the opening side of the first notch groove 13 toward the end side of the first notch groove 13. In the block 11, the block rigidity (particularly bending rigidity) increases from the opening side of the second notch groove 14 toward the terminal end side of the second notch groove 14. That is, in the block 11, the rigidity of the block is increased from the side of the lateral groove 5 located on both sides of the block 11 in the tire circumferential direction toward the end of the first notch groove 13 or the end of the second notch groove 14 in the tire circumferential direction. It has increased.
Specifically, in the block 11, as will be described in detail later, by changing the groove depth of the first notch groove 13 and the groove depth of the second notch groove 14 within the groove, The rigidity of the block is increased from the end side of the first notch groove 13 toward the end side of the second notch groove 14.
In the pneumatic tire of this example, the rigidity of the block was changed by changing the groove depth of the first notch groove and the second notch groove. However, in the pneumatic tire of the present invention, it is used for the block. The rigidity of the block may be changed by changing the rubber composition to be changed or changing the arrangement density of sipes formed on the block. However, from the viewpoint of changing the rigidity of the block using a simple configuration, it is preferable to change the rigidity of the block by changing the groove depths of the first notch groove and the second notch groove.

  The sipe 12 is not particularly limited and has a zigzag shape in plan view and is also bent in the depth direction. And the opening width of the sipe 12 is 0.3-1.5 mm, for example. In addition, the sipe 12 is extended in the direction which cross | intersects the extension direction of the horizontal groove 5 and a tire circumferential direction line on both sides. That is, the direction in which the sipe 12 is inclined with respect to the tire circumferential direction (or tire width direction) and the direction in which the lateral groove 5 is inclined with respect to the tire circumferential direction (or tire width direction) are opposite directions.

The first notch groove 13 and the second notch groove 14 are linear in a plan view, and extend obliquely to the right in FIG. 1 with respect to the tire circumferential direction. That is, the first notch groove 13 and the second notch groove 14 extend in the upper right direction in FIG.
The first notch groove 13 and the second notch groove 14 are orthogonal to the lateral groove 5. Further, between the blocks 11 adjacent to each other in the tire circumferential direction, the groove width center line of the first notch groove 13 and the groove width center line of the second notch groove 14 are located on the same straight line. That is, the lateral groove 5, the second notch groove 14 of the block 11 located on one side in the tire circumferential direction of the lateral groove 5 (lower side in FIG. 1), and the other side in the tire circumferential direction of the lateral groove 5 (upper side in FIG. 1). The first notch groove 13 of the block 11 that is positioned intersects to form a substantially cross shape.

2, the first notch groove 13 and the second notch groove 14 have a groove depth from the opening side to the lateral groove 5 to the terminal side, as shown in a cross section taken along line II in FIG. It is decreasing toward. More specifically, the groove depth of the first notch groove 13 and the second notch groove 14 is shallower than the groove depth of the lateral groove 5 at the opening position to the lateral groove 5. The first notch groove 13 and the second notch groove 14 have a groove depth that gradually decreases from the opening position to the lateral groove 5 toward the terminal position in the block 11.
Accordingly, the rigidity (particularly bending rigidity) of the block 11 gradually increases from the opening side of the first notch groove 13 toward the terminal side of the first notch groove 13, and the opening of the second notch groove 14. It gradually increases from the side toward the terminal end side of the second notch groove 14.

  The connecting narrow groove 15 has a narrower groove width than the first notch groove 13 and the second notch groove 14, and extends inclining to the left in FIG. 1 with respect to the tire circumferential direction. That is, the connecting narrow groove 15 is inclined to the side opposite to the first notch groove 13 and the second notch groove 14 and extends in the upper left direction in FIG. Therefore, in this block 11, the 1st notch groove 13, the connection fine groove 15, and the 2nd notch groove 14 are arrange | positioned so that it may become a zigzag shape. As shown in FIG. 2, the connecting narrow groove 15 has a groove depth substantially equal to the terminal side of the first notch groove 13 and the second notch groove 14.

  The width direction sipe 16 is not particularly limited, and is zigzag in a plan view and is also bent in the depth direction. And the width direction sipe 16 cross | intersects the connection fine groove 15, and is inclined with respect to the tire width direction (in FIG. 1, it goes up to the right), and is extended. The width direction sipe 16 has one end in the tire width direction terminating at a location close to the third notch groove 17 and the other end in the tire width direction terminating at a location close to the fourth notch groove 18. Here, one end of the width direction sipe 16 may open to the third notch groove 17, and the other end of the tire width direction may open to the fourth notch groove 18. In addition, the opening width of the width direction sipe 16 is, for example, 0.3 to 1.0 mm. Moreover, the depth of the width direction sipe 16 is, for example, 3.0 to 8.0 mm.

The third notch groove 17 and the fourth notch groove 18 are not particularly limited and extend in a straight line shape in plan view, inclined with respect to the tire width direction (upward in FIG. 1). . Moreover, the 3rd notch groove 17, the 4th notch groove 18, and the width direction sipe 16 are located on the same straight line.
And the groove width of the 3rd notch groove 17 and the 4th notch groove 18 is narrower than the groove width of the 1st notch groove 13 and the 2nd notch groove 14, and is larger than the opening width of the width direction sipe 16. Has also been widely used. Further, the groove depths of the third notch groove 17 and the fourth notch groove 18 are shallower than the groove depth of the first main groove 1 and the groove depth of the second main groove 2.

  The central block 31 constituting the central block row 30 positioned between the first main groove 1 and the circumferential thick groove 3 of the tread portion tread 100 has a large number of sipes 32 and one end extending in the tire width direction. An extending lateral groove 33 that is open to the first main groove 1 and whose other end terminates in the central block 31 is formed.

  Here, the sipe 32 is not particularly limited and has a zigzag shape in plan view and is also bent in the depth direction.

Further, the extending lateral groove 33 is located on the extending direction line (groove width center line) of the lateral groove 5 that defines the block 11 of the block row 10 adjacent to the central block row 30 with the first main groove 1 interposed therebetween. Yes. That is, the extending lateral groove 33 is at a position where the lateral groove 5 is extended to the central block row 30 side.
And the 1st main groove 1, the horizontal groove 5, and the extending | stretching horizontal groove 33 cross | intersect so that it may become a substantially X shape.

  Further, the arrow feather block 41 constituting the arrow feather block row 40 positioned between the circumferential thick groove 3 and the circumferential narrow groove 4 of the tread part tread surface 100 includes a first sipe 42 and a first sipe 42 each having a zigzag shape in plan view. Two composite sipes comprising two sipes 43 are formed.

  Here, the first sipe 42 has one end opened in the circumferential thick groove 3 located on the tire circumferential direction protruding portion 44 side of the arrow feather block 41 with respect to the width center line of the arrow feather block 41 and the other end is arrow feather. Terminate in block 41. The second sipe 43 has one end opened in the circumferential narrow groove 4 located on the opposite side of the widthwise center line of the arrow feather block 41 from the tire circumferential protrusion 44 side of the arrow feather block 41 and the other end. Ends in the Yaha block 41.

  The composite sipe composed of the first sipe 42 and the second sipe 43 extends in the entire tire width direction of the arrow feather block 41 with an arrangement shape corresponding to the bent lateral groove 8, and a part of the first sipe 42. And a portion of the second sipe 43 overlap in the tire circumferential direction. That is, when a composite sipe comprising the first sipe 42 and the second sipe 43 is projected onto a plane that includes the tire rotation axis and is orthogonal to the block surface, the tire width direction dimension of the projection view and the tire width direction of the arrow feather block 41 The dimensions are equal. In the projection view, the dimension component in the tire width direction of the first sipe 42 and the dimension component in the tire width direction of the second sipe 43 overlap.

  Further, a shoulder block 21 constituting a shoulder block row 20 located between the second main groove 2 and the tread end TE of the tread portion tread 100 and a shoulder block located between the circumferential narrow groove 4 and the tread end TE. The shoulder block 51 constituting the row 50 is formed with zigzag horizontal sipe 22 and 52 in plan view extending in the tire width direction and zigzag vertical sipe 23 and 53 in plan view extending in the tire circumferential direction. Yes.

  According to the pneumatic tire of this example, the tread portion tread 100 has a plurality of blocks 11 between the tire equator C and the tread end TE located on one side in the tire width direction (right side in FIG. 1). Since the row 10 is formed, snow performance such as snow brake performance, snow traction performance, and snow turning performance can be sufficiently improved.

That is, the block 11 is formed with the first notch groove 13 and the second notch groove 14 having one end opened in the lateral groove 5 and the other end terminating in the block 11, so Snow pillars can be formed in the first and second cutout grooves without escaping in the circumferential direction. In addition, the snow pillars formed in the lateral grooves 5 can be struck against the snow pillars formed in the first notch grooves 13 and the second notch grooves 14 to harden the snow pillars in the grooves. Therefore, in the region where the block row 10 is formed, in the lateral groove 5 located on both sides in the tire circumferential direction of the block 11, particularly in a portion where the lateral groove 5 intersects with the first notch groove 13 or the second notch groove 14. , Improve the ability to step on and solidify snow and increase the shear force of snow columns.
Further, in the block 11, the rigidity (particularly the bending rigidity) of the block gradually increases from the opening side (lateral groove 5 side) of the first notch groove 13 toward the terminal end side, and the second notch groove 14 It gradually increases from the opening side (lateral groove 5 side) toward the end side. Therefore, in the area where the block row 10 is formed, when traveling on a snowy road, the snow can be sufficiently grasped on the side of the lateral groove 5 where the rigidity of the block is relatively small, and the snow column shear force can be increased. Further, in the block 11, the effect of scratching the road surface by the edge can be improved on the opening side of the first notch groove 13 and the second notch groove 14, and the first notch groove 13 and the second notch groove can be improved. It is possible to secure the rigidity of the block on the terminal end side of 14 (that is, the center side in the tire circumferential direction of the block 11) and to prevent the contact area from decreasing.
Furthermore, in the block 11, the first notch groove 13 and the second notch groove 14 terminate in the block 11, so that a notch groove having a constant groove width is formed over the entire tire circumferential direction of the block 11. Compared with the case, it can suppress that the rigidity of the block 11 falls and a contact area decreases.
Moreover, in the block 11, since the 1st notch groove 13 and the 2nd notch groove 14 are connected by the connection thin groove 15, it suppresses that the rigidity of the block 11 falls, edge component, especially a tire A circumferential edge component can be secured and the effect of scratching the road surface in the tire width direction by the edge can be enhanced. Further, since the plurality of sipes 12 extending in a zigzag shape are formed, it is possible to sufficiently secure both the tire circumferential direction edge component and the tire width direction edge component and obtain the effect of scratching the road surface by the edge. In addition, it is preferable that the extending direction of the sipe 12 and the extending direction of the lateral groove 5 be a direction intersecting with the tire circumferential direction line interposed therebetween. This is because the performance on snow is further improved.
Furthermore, since the sipe 12 extending in a zigzag shape is formed in the block 11, the area of the sipe can be secured, the drainage performance can be improved, and the on-ice performance and the wet performance can be improved. Further, the small blocks can support each other in the tire circumferential direction with the sipe 12 being input to the block 11, and the overall rigidity of the block 11 can be secured to improve the steering stability.

Therefore, in the pneumatic tire of this example, in the portion where the block row 10 is formed, all of the securing of the tire contact area, the improvement of the scratching effect of the road surface by the edge, and the improvement of the snow column shear force are sufficiently high. It is possible to improve on-snow performance such as on-snow braking performance, on-snow traction performance, and on-snow turning performance by arranging the tires side by side and sufficiently enhancing the friction characteristics of the tire on the snowy road.
In the pneumatic tire of this example, in the portion where the block row 10 is formed, it is possible to achieve both the securing of the tire contact area and the improvement of the scratching effect of the road surface by the edge. For example, dry performance, wet performance, performance on ice, wear resistance, etc. can be ensured.

  Moreover, in this example pneumatic tire, since the width direction sipe 16 is formed in the block 11, it is possible to secure a tire width direction edge component and improve snow braking performance and snow traction performance. Moreover, drainage performance can be improved and wet performance can be ensured. Further, in the pneumatic tire of this example, since the width direction sipe 16 and the connecting narrow groove 15 are intersected, the width direction sipe 16 is intersected with the first notch groove 13 and the second notch groove 14 and In comparison, the edge component can be secured and the drainage performance can be improved while suppressing the rigidity of the block 11 from being significantly reduced and the contact area from being reduced.

  Further, in the pneumatic tire of this example, one end is opened to the first main groove 1 in the central block 31 of the central block row 30 adjacent to the block row 10 in the tire width direction with the first main groove 1 interposed therebetween. Since the extended horizontal groove 33 whose end terminates in the central block 31 is formed, a snow column can also be formed in the extended horizontal groove 33 without releasing the snow that has been stepped and solidified in the horizontal groove 5 in the tire width direction. Therefore, it is possible to improve the force for stepping and solidifying the snow at the portion where the lateral groove 5 and the first main groove 1 intersect, and to increase the snow column shear force. In the pneumatic tire of this example, since the extending lateral groove 33 terminates in the central block 31, it is possible to suppress a decrease in rigidity of the central block 31 and to suppress a decrease in steering stability. .

Further, in the pneumatic tire of this example, the first notch groove 13, the connecting narrow groove 15, and the second notch groove 14 are arranged in the block 11 in a zigzag shape. A direction edge component can be secured, and snow braking performance and snow traction performance can be improved.
Further, in the pneumatic tire of this example, the groove width of the lateral groove 5 is gradually reduced from the second main groove 2 side toward the first main groove 1 side, so that it is possible to suppress a decrease in rigidity of the block 11, Snow traction performance can be improved effectively.

  Here, from the viewpoint of sufficiently suppressing the decrease in rigidity of the block 11 and sufficiently securing the ground contact area, the groove width (opening width) of the first notch groove 13 and the second notch groove 14 is, for example, 6 mm. The length in the extending direction of the first cutout groove 13 and the second cutout groove 14 is preferably, for example, 25 mm or less, and the first cutout groove 13 and the second cutout groove 14 are preferable. It is preferable that the tire circumferential direction length is 1/3 or less of the tire circumferential direction length of the block 11. Also, from the viewpoint of improving the snow column shear force by stepping and solidifying a sufficient amount of snow in the first notch groove 13 and the second notch groove 14, the first notch groove 13 and the second notch groove 14. The groove width (opening width) is preferably 1.2 mm or more, for example, and the lengths in the extending direction of the first notch groove 13 and the second notch groove 14 are preferably 5 mm or more, for example.

Furthermore, from the viewpoint of sufficiently suppressing the decrease in the rigidity of the block 11 and sufficiently securing the ground contact area, the groove depth (groove depth of the first notch groove 13 and the second notch groove 14 on the end side). The minimum value is preferably 3 mm or less. From the viewpoint of forming a sufficient amount of snow pillars in the first notch groove 13 and the second notch groove, the groove depth on the terminal side of the first notch groove 13 and the second notch groove 14 ( The minimum value of the groove depth is preferably 1 mm or more.
Further, from the viewpoint of sufficiently grasping snow on the side of the lateral groove 5 and increasing the snow column shearing force, the groove depths on the opening side of the first notch groove 13 and the second notch groove 14 (maximum groove depth). Is preferably 5 mm or more. From the viewpoint of suppressing a significant decrease in the rigidity of the block 11, the groove depth (maximum value of the groove depth) on the opening side of the first notch groove 13 and the second notch groove 14 is 8 mm or less. It is preferable to do.

Further, from the viewpoint of increasing the force of stepping and solidifying snow in the lateral groove 5 and improving the snow column shearing force, the angle formed by the tire width direction line and the lateral groove 5 (that is, the inclination angle of the lateral groove 5 with respect to the tire width direction) is: It is preferable that the angle be 0 ° or more and 45 ° or less.
Furthermore, from the viewpoint of increasing the force for stepping and solidifying the snow at the portion where the lateral groove 5 and the first notch groove 13 or the second notch groove 14 intersect, the first notch groove 13 is improved. The angle formed between the extending direction of the second notch groove 14 and the extending direction of the lateral groove 5 is preferably 45 ° or more as measured from the acute angle side, and the first notched groove 13 and the second notched groove 13 It is particularly preferable that the extending direction of the notch groove 14 and the extending direction of the lateral groove 5 are orthogonal to each other.

  Further, from the viewpoint of sufficiently suppressing the decrease in rigidity of the block 11 and sufficiently securing the ground contact area, the groove width (opening width) of the connecting narrow groove 15 is preferably set to, for example, 1.5 mm or less. From the viewpoint of tire manufacture, the groove width of the connecting narrow groove 15 is preferably 0.3 mm or more.

Further, in the pneumatic tire of this example, an arrow composed of a plurality of arrow blade blocks 41 on the tread portion tread surface 100 from the tire equator C to the tread end TE located on the other side in the tire width direction (left side in FIG. 1). Since the wing block row 40 is formed, on-ice performances such as on-ice brake performance, on-ice traction performance, and on-ice turning performance can be improved. Therefore, in this example pneumatic tire, the performance on snow is improved on one side of the tread surface 100 (right side in FIG. 1), while the performance on ice is improved on the other side (left side in FIG. 1) of the tread surface 100. Therefore, the performance on snow and the performance on ice can be improved in a well-balanced manner.
In the region where the arrow feather block row 40 is formed, in the arrow feather block 41, the contact area is ensured by suppressing the collapse of the portion where the tire circumferential protrusion 44 is located, and the feather part of the arrow feather block 41 (tire width direction). Since it is possible to achieve both improvement of the scratching effect of the road surface by the edges of both ends and the edge of the composite sipe, it is possible to improve the performance on ice.

  As mentioned above, although embodiment of this invention was described with reference to drawings, the pneumatic tire of this invention is not limited to the said example, A change can be suitably added to the pneumatic tire of this invention. . Specifically, the pneumatic tire of the present invention may have a line-symmetric pattern centered on the tire equator.

  According to the present invention, sufficient friction characteristics on a snowy road can be obtained by ensuring that the contact area of the tire, the improvement of the scratching effect of the road surface by the edge, and the improvement of the shear force of the snow column are juxtaposed at a sufficiently high level. It is possible to provide a pneumatic tire with excellent performance on snow.

DESCRIPTION OF SYMBOLS 1 1st main groove 2 2nd main groove 3 Circumferential thick groove 4 Circumferential thin groove 5 Lateral groove 6 Lug groove 7 Central lateral groove 8 Bending lateral groove 9 Lug groove 10 Block row 11 Block 12 Sipe 13 1st notch groove 14 2nd Notch groove 15 Connecting narrow groove 16 Width direction sipe 17 Third notch groove 18 Fourth notch groove 20 Shoulder block row 21 Shoulder block 22 Horizontal sipe 23 Vertical sipe 30 Central block row (land portion row)
31 Central block 32 Sipe 33 Stretched lateral groove 40 Arrow feather block row 41 Arrow feather block 42 First sipe 43 Second sipe 44 Tire circumferential protrusion 50 Shoulder block row 51 Shoulder block 52 Horizontal sipe 53 Vertical sipe 100 Tread part tread

Claims (7)

One or more main grooves extending in the tire circumferential direction on at least a part of the tread portion tread located between both tread ends, and / or a plurality of main grooves extending in the tire width direction between the main grooves and / or between the main grooves and the tread ends A pneumatic tire formed by partitioning a block row of a plurality of blocks and disposing at least one sipe in the block,
A first notch groove having one end opened in a lateral groove located on one side in the tire circumferential direction of the block and the other end terminated in the block;
A second notch groove having one end opened in the lateral groove located on the other side in the tire circumferential direction of the block and the other end terminated in the block;
Connecting the first cutout groove and the second cutout groove, and a connecting narrow groove having a narrower groove width than the first cutout groove and the second cutout groove;
Formed in the block,
By changing one or more of the rubber composition used for the block and the density of sipes formed on the block, the rigidity of the block changes from the opening side of the first notch groove to the first notch groove. A pneumatic tire characterized by increasing toward the end side of the second notch and increasing from the opening side of the second notch groove toward the end side of the second notch groove. The arrangement density of the sipes decreases from the opening side of the first notch groove toward the terminal end side of the first notch groove, and from the opening side of the second notch groove to the second notch groove. The pneumatic tire according to claim 1 , wherein the pneumatic tire decreases toward an end side. The said block, characterized by having a width direction sipes extending in the tire width direction intersects with the connecting narrow grooves, the pneumatic tire according to claim 1 or 2. The first cutout groove and the second cutout groove are inclined and extend in the same direction with respect to the tire circumferential direction,
The connecting narrow groove, characterized in that it extends inclined opposite to the first notched groove and the second cut-out groove with respect to the tire circumferential direction, of claim 1-3 The pneumatic tire according to any one of the above. The tread portion tread has a land portion row adjacent to the block row across the main groove,
An extending lateral groove having one end opened in the main groove and the other end terminated in the land portion row is formed in a portion of the land portion row located on the extending direction line of the lateral groove. The pneumatic tire according to any one of claims 1 to 4 . The first notch groove extends in a direction orthogonal to a lateral groove located on one side in the tire circumferential direction of the block,
The second notched groove is characterized by extending in a direction perpendicular to the transverse grooves located in the tire circumferential direction the other of the blocks, the pneumatic tire according to any one of claims 1-5. The tread part tread is different from the shape from the tire equator to the tread end located on one side in the tire width direction, and the shape from the tire equator to the tread end located on the other side in the tire width direction,
Said block is characterized by being formed from the tire equator to one side in the tire width direction, the pneumatic tire according to any one of claims 1-6.

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