JP2007099160A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of enhancing the steering stability, in particular, the steering stability on a dry road surface by increasing the strength against the lateral force in cornering while ensuring the starting performance and the braking performance on a snowy road surface. <P>SOLUTION: The pneumatic tire 1 has a tread pattern having a sipe 9 extending in the tread width direction in a block 7 demarcated by a plurality of circumferential grooves 3 extending in the tire circumferential direction and a plurality of grooves 5 in the width direction extending in the tread width direction in a tread surface. In this case, the sipe 9 extends with different thickness in the tread width direction, and also extends with different thickness in the tire radial direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire having a tread pattern in which sipes are provided in blocks defined by a plurality of circumferential grooves and a plurality of width grooves.

  Conventionally, various proposals have been made on pneumatic tires that improve the starting and braking performance on the road surface on snow. For example, on the tread surface, a block defined by a plurality of circumferential grooves extending in the tire circumferential direction and a plurality of width grooves extending in the tread width direction is provided by the circumferential grooves and the width grooves. There is also known a pneumatic tire having a tread pattern provided with a thin sipe (see, for example, Patent Document 1).

Since this pneumatic tire is provided with a sipe, the groove area on the tread surface is increased, and the grip force (so-called edge effect) is improved, so that the starting and braking performance on the road surface on snow is improved. .
Japanese Patent Laid-Open No. 2001-191740 (page 2 to page 3, FIG. 1)

  However, although the conventional pneumatic tire described above has an increased groove area on the tread surface, the steering stability on the snowy road surface is improved, but the rigidity of the block is reduced, so the steering stability on the dry road surface is reduced. The nature will decline. In particular, with conventional pneumatic tires, as the sipe depth is set deeper, the block rigidity further decreases, the strength against lateral force from the lateral direction is weak when cornering on dry road surfaces, and steering stability The nature will decline.

  Therefore, the present invention increases the strength against lateral force during cornering while ensuring start / braking performance on a snowy road surface, and can improve steering stability, in particular, steering stability on a dry road surface. An object is to provide a tire entering.

  In order to solve the above-described problems, the present invention has the following features. First, the first feature of the present invention is that the tread has a tread on a block partitioned by a plurality of circumferential grooves extending in the tire circumferential direction and a plurality of widthwise grooves extending in the tread width direction. A pneumatic tire having a tread pattern provided with a sipe extending in the width direction, the sipe extending in a different thickness toward the tread width direction, and in the tire radial direction with different thicknesses The gist is that it extends.

  According to this feature, the sipe extends in the tire radial direction with different thicknesses, so that the strength against lateral force during cornering is increased while securing start / braking performance on the road surface on snow. Maneuvering stability, particularly, maneuvering stability on a dry road surface can be improved.

  Specifically, the sipe located in the thick area in the block can improve the clipping force on the snowy road surface and increase the frictional force with the road surface, ensuring start and braking performance on the snowy road surface. it can.

  On the other hand, the sipes located in a thin area in the block can suppress a decrease in the rigidity of the block, and increase the strength against lateral force during cornering to improve steering stability, especially on dry road surfaces. Can be improved.

  In this way, while ensuring start and braking performance on the snowy road surface, it is possible to improve the steering stability by increasing the strength against the lateral force during cornering, so the steering stability on the dry road surface and the snowy road surface is improved. A pneumatic tire that can be made compatible can be provided.

  The gist of the second feature of the present invention is that the sipe extends while repeating a zigzag shape in the tread width direction.

  According to this feature, the sipe extends while repeating a zigzag shape in the tread width direction, so that the deformation of the block can be suppressed (that is, the decrease in the rigidity of the block can be further suppressed), and the cornering can be performed. It is possible to improve the steering stability (particularly, the driving stability on the dry road surface) by increasing the strength against the lateral force at.

  The gist of the third feature of the present invention is that the sipe extends while repeating a zigzag shape in the tire radial direction.

  According to such a feature, the sipe extends while repeating a zigzag shape toward the tire radial direction, so that a decrease in the rigidity of the block can be further suppressed, and the strength against the lateral force during cornering is increased and maneuvered. Stability (especially steering stability on a dry road surface) can be improved.

  In addition, the sipe extends while repeating a zigzag shape toward the tire radial direction, so that a decrease in the rigidity of the block can be further suppressed, and the strength against lateral force during cornering is increased, thereby improving steering stability (particularly , Driving stability on a dry road surface) can be improved.

  According to a fourth aspect of the present invention, the first ridge line extending in the tread width direction on one side wall surface of the sipe has a zigzag shape and extends in the tread width direction on the other side wall surface of the sipe. The gist is that the two ridge lines repeat a zigzag shape.

  According to such a feature, the first ridge line and the second ridge line have a zigzag shape repeatedly, so that it is possible to further suppress a decrease in the rigidity of the block, and to increase the strength against lateral force during cornering, thereby improving steering stability. (In particular, steering stability on a dry road surface) can be further improved.

  The gist of the fifth feature of the present invention is that the tread pattern is a symmetrical pattern with respect to the tire equator line, and the thicker side of the sipe is located on the tire equator line side.

  According to such a feature, the tread pattern is a symmetric pattern with respect to the tire equator line, and the side where the sipe is thick is located on the tire equator line side, thereby further increasing the strength against lateral force during cornering. This makes it possible to further improve the handling stability on the dry road surface and to ensure the start / braking performance on the snowy road surface.

  The sixth feature of the present invention is summarized in that the tread pattern is an asymmetrical pattern with respect to the tire equator line, and the thicker side of the sipe is located on the inner side when the vehicle is mounted.

  According to such a feature, the tread pattern is an asymmetric pattern with respect to the tire equator line, and the side where the sipe is thick is located on the inner side when the vehicle is mounted, thereby further increasing the strength against lateral force during cornering. This makes it possible to further improve the handling stability on the dry road surface and to ensure the start / brake performance on the road surface on snow.

  The gist of the seventh feature of the present invention is that the thickness of the sipe located in the thin region is 0.4 to 1.0 mm.

  If the thickness of the sipe located in the thin area is smaller than 0.4 mm, the frictional force with the snow on the snowy road surface will be small, and the start / braking performance on the snowy road surface cannot be secured. There is. Also, if the thickness of the sipe located in the thin area is larger than 1.0 mm, the strength against the lateral force during cornering may be weakened, and the steering stability on the dry road surface cannot be improved. There is.

  The gist of the eighth feature of the present invention is that the thickness of the sipe located in the thick region is 1.0 to 2.5 mm.

  In addition, if the thickness of the sipe located in the thick region is smaller than 1.0 mm, it becomes difficult to obtain a large frictional force on the snowy road surface. There are cases where it cannot be increased. Also, if the thickness of the sipe located in the thick area is larger than 2.5 mm, the strength against the lateral force during cornering may be weakened, and the steering stability on the dry road surface cannot be improved. There is.

  The ninth feature of the present invention is summarized in that a value obtained by dividing the thickness of a sipe located in a thick region by the thickness of a sipe located in a thin region is 2.0 or more.

  If the value obtained by dividing the thickness of the sipe located in the thick region by the thickness of the sipe located in the thin region is smaller than 2.0, it is not possible to obtain a sipe having a different thickness in the tread width direction. In some cases, it may not be possible to improve driving stability on a dry road surface while securing start / braking performance on a snowy road surface.

  According to the present invention, the sipe extends in the tread width direction with different thicknesses, and extends in the tire radial direction with different thicknesses. It is possible to provide a pneumatic tire capable of improving steering stability, particularly steering stability on a dry road surface by increasing strength against a lateral force during cornering while ensuring braking performance.

  Next, an example of a pneumatic tire according to the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  FIG. 1 is a development view illustrating a tread pattern of a pneumatic tire according to the present embodiment, and FIG. 2 is an enlarged perspective view illustrating blocks constituting the tread pattern of the pneumatic tire according to the present embodiment. 3 is an enlarged perspective view showing only the sipes constituting the tread pattern of the pneumatic tire according to the present embodiment.

  Here, the pneumatic tire 1 according to the present embodiment is a general radial tire including a bead portion, a carcass layer, and a belt layer (not shown). In addition, the pneumatic tire 1 (tread pattern) according to the present embodiment is a symmetrical pattern with respect to the tire equator line CL.

  As shown in FIGS. 1 to 3, the pneumatic tire 1 includes, on the tread surface, a plurality of circumferential grooves 3 extending in the tire circumferential direction and a plurality of widthwise grooves 5 extending in the tread width direction. A sipe 9 extending in the tread width direction is provided in the partitioned block 7.

  The sipes 9 extend in different thicknesses in the tread width direction, and extend in the tire radial direction with different thicknesses. Further, the thicker side (T2 side) of the sipe 9 is located on the tire equator line CL side in order to increase the strength against lateral force during cornering.

  Further, the sipe 9 extends while repeating a zigzag shape in the tread width direction. The sipe 9 extends while repeating a zigzag shape in the tire radial direction.

  Moreover, as shown to Fig.3 (a), the 1st ridgeline 9a extended toward the tread width direction in one side wall surface 9A of the sipe 9 has repeated zigzag shape. Moreover, the 2nd ridgeline 9b extended toward the tread width direction in the other side wall surface 9B of the sipe 9 has repeated zigzag shape.

  As shown in FIG. 3A, the first ridge line 9a and the second ridge line 9b have substantially the same shape as the surface of the sipe 9, but it is not always necessary to have the same shape. Different shapes may be used.

  Here, as shown in FIGS. 3A and 3B, the thickness (T1) of the sipe 9 located in the thin region is preferably 0.4 to 1.0 mm.

  If the thickness (T1) of the sipe 9 located in this thin area is less than 0.4 mm, the frictional force with the snow on the snowy road surface will be reduced, and start / braking performance on the snowy road surface will be ensured. This is because there is a case that cannot be done. Further, if the thickness (T1) of the sipe 9 located in a thin region is larger than 1.0 mm, the strength against the lateral force at the time of cornering may be weakened, and the steering stability on the dry road surface is improved. This is because there are cases where it cannot be done.

  Moreover, as shown to Fig.3 (a) and FIG.3 (c), it is preferable that the thickness (T2) of the sipe 9 located in a thick area | region is 1.0-2.5 mm.

  If the thickness (T2) of the sipe 9 located in this thick region is smaller than 1.0 mm, it becomes difficult to obtain a large frictional force on the snowy road surface, and the start / braking performance on the snowy road surface is difficult. This is because the improvement allowance may not be large. Further, if the thickness (T2) of the sipe 9 located in the thick region is larger than 2.5 mm, the strength against the lateral force at the time of cornering may be weakened, and the driving stability on the dry road surface is improved. This is because there are cases where it cannot be done.

  Further, the value obtained by dividing the thickness (T2) of the sipe 9 located in the thick region by the thickness (T2) of the sipe 9 located in the thin region is preferably 2.0 or more. That is, the sipe 9 preferably satisfies 2.0 ≦ T2 / T1.

  When the value obtained by dividing the thickness (T2) of the sipe 9 located in the thick region by the thickness (T1) of the sipe 9 located in the thin region is smaller than 2.0 (that is, 2.0> T2 / T1). This is not enough to make the sipe with different thicknesses in the tread width direction, and it is possible to improve the driving stability on the dry road surface while ensuring the start / brake performance on the road surface on snow. This is because there are cases where it is not possible.

(Modification 1)
As described above, the contents of the present invention have been disclosed through one embodiment of the present invention. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  Although the sipe 9 of the pneumatic tire 1 according to the above-described embodiment has been described as extending in a zigzag shape in the tread width direction and the tire radial direction, the sipe 9 can be modified as follows. In addition, the part which is different from the pneumatic tire which concerns on embodiment of this invention mentioned above is mainly demonstrated.

  For example, as shown in FIG. 4, the sipe 9 has a different thickness at the center of the sipe 9 and extends in the tread width direction, and extends in the tire radial direction with a different thickness. Also good.

  Further, as shown in FIG. 5, the sipe 9 may gradually have different thicknesses in the tread width direction, and may extend in the tire radial direction while the surface is triangular.

(Modification 2)
Moreover, although the pneumatic tire 1 (tread pattern) which concerns on embodiment mentioned above was demonstrated as what is a symmetrical pattern on the basis of the tire equator line CL, you may change as follows.

  For example, as shown in FIG. 6, the pneumatic tire 1 may have an asymmetric pattern with respect to the tire equator line. In this case, as shown in FIG. 6, in order to further increase the strength against lateral force during cornering, it is preferable that the thicker side (T2 side) of the sipe 9 is located on the inner side when the vehicle is mounted.

[Other Embodiments]
Although the contents of the present invention have been disclosed through the embodiments of the present invention as described above, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention.

  Specifically, although the pneumatic tire 1 according to the present embodiment has been described as a general radial tire including a bead portion, a carcass layer, and a belt layer (not shown), the pneumatic tire 1 is not limited thereto. Of course, tires other than radial tires (for example, bias tires) may be used.

  Further, although one sipe 9 is described as being formed in each block 7, the present invention is not limited to this, and a plurality of (for example, two) sipe 9 may be formed in each block 7.

  From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

(Action / Effect)
According to the pneumatic tire 1 according to the present embodiment described above, the sipe 9 extends in the tire radial direction with different thicknesses, thereby ensuring start / braking performance on the road surface on snow, By increasing the strength against lateral force during cornering, it is possible to improve steering stability, particularly steering stability on a dry road surface.

  Specifically, the sipe 9 located in the thick area in the block 7 can improve the clipping force on the road surface on the snow and increase the frictional force with the road surface, ensuring start / brake performance on the road surface on the snow. can do.

  On the other hand, the sipe 9 located in a thin area in the block 7 can suppress a decrease in the rigidity of the block and increase the strength against the lateral force during cornering to improve the steering stability, particularly on the dry road surface. Can be improved.

  In this way, while ensuring start and braking performance on the snowy road surface, it is possible to improve the steering stability by increasing the strength against the lateral force during cornering, so the steering stability on the dry road surface and the snowy road surface is improved. The pneumatic tire 1 that can be made compatible can be provided.

  Further, the sipe 9 extends while repeating a zigzag shape in the tread width direction, so that the deformation of the block 7 can be suppressed (that is, the decrease in rigidity of the block 7 can be further suppressed). It is possible to improve the steering stability (particularly, the steering stability on the dry road surface) by increasing the strength against the lateral force.

  Furthermore, since the sipe 9 extends while repeating a zigzag shape toward the tire radial direction, it is possible to further suppress a decrease in the rigidity of the block 7 and to increase the strength against the lateral force during cornering, thereby improving the steering stability. (Especially, steering stability on a dry road surface) can be improved.

  Further, since the sipe 9 extends while repeating a zigzag shape toward the tire radial direction, it is possible to further suppress the decrease in the rigidity of the block 7 and to increase the strength against the lateral force during cornering, thereby improving the steering stability. (Especially, steering stability on a dry road surface) can be improved.

  Furthermore, since the first ridge line 9a and the second ridge line 9b repeat the zigzag shape, the rigidity of the block 7 can be further prevented from being lowered, and the strength against the lateral force during cornering is increased to improve the steering stability ( In particular, steering stability on a dry road surface can be further improved.

  Further, the tread pattern is a symmetric pattern with respect to the tire equator line CL, and the side where the thickness of the sipe 9 is thick (T2 side) is located on the tire equator line CL side. It is possible to further increase the strength, to further improve the handling stability on the dry road surface, and to ensure the starting / braking performance on the road surface on snow.

  Furthermore, the tread pattern is an asymmetrical pattern with respect to the tire equator line CL, and the side where the thickness of the sipe 9 is thick (T2 side) is located on the inner side when the vehicle is mounted, thereby increasing the strength against lateral force during cornering. Further, it is possible to further increase the driving stability on the dry road surface, and it is possible to ensure the start / brake performance on the road surface on snow.

  Next, in order to further clarify the effects of the present invention, the results of tests performed using pneumatic tires according to the following comparative examples and examples will be described. In addition, the data regarding each pneumatic tire were measured on the conditions shown below.

・ Tire size: 205 / 60R15 91T
・ Wheel size: 15 × 6J
-Vehicle type: FF vehicle (displacement 1.800cc)
・ Internal pressure condition: Regular internal pressure (vehicle specified internal pressure)
In addition, the structure other than the sipe of each pneumatic tire shall be the same. The sipe of each pneumatic tire will be described with reference to Table 1 and the drawings.

  Each pneumatic tire has, on the tread surface, a block 70 defined by a plurality of circumferential grooves 30 extending in the tire circumferential direction and a plurality of widthwise grooves 50 extending in the tread width direction. A sipe extending to is provided.

  As shown in FIG. 7, the sipe 90 </ b> A of the pneumatic tire 100 </ b> A according to Comparative Example 1 extends with the same thickness in the tread width direction (that is, there is no change in thickness). The sipe 90A extends in the tire radial direction with the same thickness. As shown in Table 1, the thickness (T1) of the sipe 90A is 0.7 mm.

  As shown in FIG. 8, the sipe 90B of the pneumatic tire 100B according to Comparative Example 2 extends with the same thickness in the tread width direction (that is, there is no change in the thickness). Further, the sipe 90B extends in the tire radial direction with the same thickness. As shown in Table 1, the thickness (T1) of the sipe 90B is 2.0 mm.

  As shown in FIG. 9, the sipe 90C of the pneumatic tire 100C according to the first embodiment has different thicknesses at the center of the sipe 90C and extends in the tread width direction, and the tires with the different thicknesses. It extends toward the radial direction. As shown in Table 1, the thickness (T1) of the sipe 90C located in the thin region is 0.7 mm, and the thickness (T2) of the sipe 90C located in the thick region is 2.0 mm.

  In addition, the pneumatic tire 100C (tread pattern) according to the first embodiment is a symmetrical pattern with respect to the tire equator line CL. Furthermore, the thick side (T2 side) of the sipe 90C is located on the tire equator line CL side.

  The sipe 9 of the pneumatic tire 1 according to Example 2 is the one shown in FIGS. 1 to 3 of the above-described embodiment. As shown in Table 1, the thickness (T1) of the sipe 9 located in this thin region is 0.7 mm, and the thickness (T2) of the sipe 9 located in the thick region is 2.0 mm.

The start / braking performance and steering stability of the pneumatic tires according to Comparative Examples 1 and 2 and Examples 1 and 2 will be described with reference to Table 2.

<Startability (snow surface)>
Each pneumatic tire was mounted on a vehicle, and the time from a speed of 0 km / h to 25 km / h was measured in a test course on a snowy road surface. Note that the shorter the time from the speed of 0 km / h to 25 km / h, the better the startability.

  As a result, it was found that the pneumatic tires according to Example 1 and Example 2 were superior to the pneumatic tire according to Comparative Example 1 in starting performance on the road surface on snow.

<Brake performance (snow surface)>
Each pneumatic tire was mounted on a vehicle, and the distance from when the brake was applied at a speed of 25 km / h to 0 km / h was measured in a test course on a snowy road surface. The shorter the distance from the speed 25 km / h to 0 km / h, the better the braking performance.

  As a result, it was found that the pneumatic tires according to Example 1 and Example 2 were superior in braking performance on a snowy road surface as compared with the pneumatic tire according to Comparative Example 1.

<Maneuvering stability (dry road surface)>
Each pneumatic tire was mounted on a vehicle, and the vehicle was run on a dry road test course at a constant speed, and the driving stability of the vehicle on which each pneumatic tire was mounted was evaluated by a professional driver (up to 10 points). The larger the index, the better the steering stability.

  As a result, it was found that the pneumatic tires according to Example 1 and Example 2 were superior in handling stability on the dry road surface as compared with the pneumatic tire according to Comparative Example 2. In particular, the pneumatic tire according to Example 2 was found to be excellent in handling stability on a dry road surface.

  As described above, the pneumatic tires according to Example 1 and Example 2 to which the present invention is applied have increased driving strength and stability against cornering while ensuring start / braking performance on snow. In particular, it has been found that steering stability on a dry road surface can be improved.

It is an expanded view which shows the tread pattern of the pneumatic tire which concerns on this embodiment. It is an expansion perspective view which shows the block which comprises the tread pattern of the pneumatic tire which concerns on this embodiment. It is an expansion perspective view which shows only the sipe which comprises the tread pattern of the pneumatic tire which concerns on this embodiment. It is an expansion perspective view which shows only the sipe which comprises the tread pattern of the pneumatic tire which concerns on the example 1 of a change (the 1). It is an expansion perspective view which shows only the sipe which comprises the tread pattern of the pneumatic tire which concerns on the example 1 of a change (the 2). It is an expanded view which shows the tread pattern of the pneumatic tire which concerns on the example 2 of a change. It is an expansion perspective view which shows the block which comprises the tread pattern of the pneumatic tire which concerns on the comparative example 1. It is an expansion perspective view which shows the block which comprises the tread pattern of the pneumatic tire which concerns on the comparative example 2. It is an expansion perspective view which shows the block which comprises the tread pattern of the pneumatic tire which concerns on Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,100A, 100B, 100C ... Pneumatic tire, 3, 30 ... Circumferential groove, 5, 50 ... Width direction groove, 7, 70 ... Block, 9, 90A, 90B, 90C ... Sipe, 9A ... One side wall surface , 9B ... the other side wall surface, 9a ... first ridgeline, 9b ... second ridgeline, CL ... tire equator line

Claims (9)

A tread pattern in which a sipe extending in the tread width direction is provided in a block defined by a plurality of circumferential grooves extending in the tire circumferential direction and a plurality of width grooves extending in the tread width direction on the tread surface A pneumatic tire having
The sipe extends in the tire radial direction with different thicknesses extending in the tread width direction, and extends in the tire radial direction with different thicknesses.   The pneumatic tire according to claim 1, wherein the sipe extends while repeating a zigzag shape in a tread width direction.   The pneumatic tire according to claim 1, wherein the sipe extends while repeating a zigzag shape in a tire radial direction. The first ridge line extending in the tread width direction on one side wall surface of the sipe has a zigzag shape,
The pneumatic tire according to claim 3, wherein the second ridge line extending in the tread width direction on the other side wall surface of the sipe repeats a zigzag shape. The tread pattern is a symmetrical pattern with respect to the tire equator line,
The pneumatic tire according to any one of claims 1 to 4, wherein the thicker side of the sipe is located on the tire equator line side. The tread pattern is an asymmetric pattern with respect to the tire equator line,
The pneumatic tire according to any one of claims 1 to 4, wherein the thicker side of the sipe is located on the inner side when the vehicle is mounted.   The pneumatic tire according to any one of claims 1 to 6, wherein a thickness of the sipe located in a thin region is 0.4 to 1.0 mm.   The pneumatic tire according to any one of claims 1 to 7, wherein a thickness of the sipe located in a thick region is 1.0 to 2.5 mm.   9. The value obtained by dividing the thickness of the sipe located in the thick region by the thickness of the sipe located in the thin region is 2.0 or more. The pneumatic tire according to item.

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