JPH08332810A - Pneumatic tire - Google Patents

Abstract

PURPOSE: To attain the traveling applicability to the frozen road surface and snowy road surface in a studless tire. CONSTITUTION: A tread face 2 is formed into a block pattern, fine irregularities 5 are provided on the surface of each block 3. Sipes 6 are provided on the block 3, and they are roughened. The applicability to the frozen road surface is attained by roughened irregularities, the applicability to the snowy road surface is attained by the blocks 3 themselves, and the applicability to the road surface where water films are generated is attained by fine irregularities 5 as the intermediate action between them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire having excellent running performance on a frozen road surface and a snow-covered road surface.

[0002]

2. Description of the Related Art In recent years, spiked tires have been refrained from being used as tires suitable for running on icy road surfaces. For example, a rubber material containing a different substance such as resin or fiber is used to roughen the block surface. Surface-mounted studless tires and the like are known. On the other hand, for tires suitable for running on snowy roads, various combinations of land pattern protrusion dimensions, mutual spacing, hardness, shape, etc. in the block pattern improve snow gripping, etc., thereby preventing traction and skidding. Various types of snow tires have been developed to bring out their actions.

[0003] On a snow-covered road surface, the ice-burned state may occur due to the snow being squeezed, and like a frozen road surface, a mirror-like state may occur. Therefore, it is generally preferable to take both measures against frozen road surfaces (roughening of the block surface) and against snowy road surfaces (various improvements in block pattern) regardless of whether the tire is a snow tire or a studless tire. It is said that.

[0004]

By the way, on a frozen road surface or a snow-covered road surface, a water film may be generated on the tire tread surface as the tire runs. In such a case, the measures against the frozen road surface or the snow-covered road surface as described above cannot be fully dealt with, which may lead to the occurrence of slip. Conventionally, a method of providing a sipe in each block has been adopted as a means for eliminating such a water film, but the sipe alone cannot obtain a satisfactory effect.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pneumatic tire which can cope with a wide range of road surface conditions from a frozen road surface to a snow-covered road surface and which is excellent in running performance. To do.

[0006]

In order to achieve the above object, the present invention takes the following technical means. That is, the present invention is characterized in that, in a tire having a block pattern on the tread surface, fine irregularities are provided on the surface of each block. It is preferable that the block has a rough surface formed by using a different material-containing rubber material or a foaming rubber material or by embossing during molding.

It is preferable that the block is provided with a sipe.

[0008]

[Operation] For the surface of the block (the surface that contacts the road surface),
By providing fine irregularities (smaller than the block and larger than the rough surface irregularity), it is possible to further improve the running applicability in a wide range of road surface conditions from the frozen road surface to the compressed snow road surface. Needless to say, if the surface of the block is roughened and sipes are used in combination, a synergistic effect with them can be expected, which is more effective.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of a pneumatic tire 1 according to the present invention, which corresponds to an enlarged view of part A of FIG. 2, 2 is a tread surface having a block pattern, and 3 is a block. Is.

In this tire 1, fine irregularities 5 and sipes 6 are provided on the surface of the block 3 (the surface that contacts the road surface), and the entire surface including the irregularities 5 of each block 3 is rough. Has been formed. Each unevenness 5 has a groove shape whose longitudinal direction is oriented in a direction orthogonal to the traveling direction (rotational direction of the tire 1), and a large number of them are arranged along the traveling direction. The height difference size, pitch, etc. of the unevenness 5 are all in the range of 0.1 to several mm, and the density and roughness of the rough surface unevenness, the direction / number / depth of the sipes 6, or the running required for the tire 1 Performance and application (applicable model)
It is appropriately selected according to the above.

As shown in FIG. 3, the unevenness 5 is well compatible with some unevenness on the road surface R, and improves the frozen road performance and the snow-covered road performance. Also, a water film H on the road surface R
In the case of occurrence of water, in the concavo-convex portion 5, water from the preceding convex portion in the traveling direction (see the white arrow) to the concave portion on the trailing side (from right to left in FIG. 3). While extruding, the water film is broken, which has the effect of preventing slippage.

As is clear from the relationship with the road surface frictional force shown in FIG. 4, the direction of the unevenness 5 is orthogonal to the traveling direction (see FIGS. 1, 6 (a), 6 (b), etc.). Although the highest frictional force can be generated in the case where the unevenness 5 is not provided even when parallel to the traveling direction (see FIG. 6C) or inclined (see FIG. 6D), The effect of increasing the frictional force is sufficiently recognized as compared with the conventional tire).

The sipe 6 is provided so as to face the same direction as the unevenness 5 as shown in FIGS. 1 and 3 (that is, orthogonal to the traveling direction), and preferably corresponds to the recessed part in the unevenness 5. It is considered to be positioned. In this embodiment, among the sipes 6, the one provided on the block 3 closest to the shoulder portion of the tire 1 is opened only on the inner side in the width direction, and is provided on the blocks 3 other than the above. Are provided so that both sides in the width direction are opened.

Needless to say, such a sipe 6 has a function of cutting off the water film H formed on the road surface R, so that the water film breaking action is synergistic with the familiar effect on the road surface due to the unevenness 5 described above. It will be further enhanced. Further, in combination with the concavities and convexities 5, the action of enhancing the drainage property is obtained, so that the action of breaking the water film by the irregularities 5 can be further enhanced.

The rough surface unevenness provided on the surface of the block 3 is made of a rubber material containing (mixing) a different substance 8 (see FIGS. 2 and 3) in the tire 1 (at least the tread portion).
It is formed by manufacturing. As the different substance 8, a granular material or a fibrous material such as a resin material, a metal material, sand, glass, graphite or the like can be used alone or in combination.

In the present embodiment, 100 parts by weight of a diene or non-diene rubber, 2 to 15 parts by weight of a nylon resin having an average particle size of 20 to 50 μm, and a suitable blowing agent 1 to 1 such as dinitrosopentamethylenetetramine. A mixture of 3 parts by weight and 3 parts by weight was used. As a result, the average roughness of the rough surface formed on the surface of the block 3 was 20 to 40 μm. In addition, in order to make the surface of the block 3 rough, there is another method in which a foamable rubber material containing no different substance 8 is used.

It is also possible to adopt a method in which the surface of the block 3 is roughened by embossing without using any foreign substance or foaming agent. In the tire 1 having the unevenness 5, the sipes 6 and the rough surface unevenness as described above, the frozen road surface applicability is obtained by the unevenness of the μm order due to the rough surface unevenness on the surface of the block 3 as shown in FIG. cm
Applicability on snowy roads is obtained with irregularities of the order, and in the middle of these, applicability to water film generation road surfaces is obtained with irregularities of the mm order by the irregularities 5 according to the present invention.

FIGS. 6 (a) to 6 (e) show the second to sixth embodiments of the tire 1 according to the present invention. In the second embodiment shown in FIG. 6 (a), the sipe 6 is in the traveling direction (white). In the third embodiment shown in (b), a through groove 10 is provided instead of the sipe. Also, (c)
In the fourth embodiment shown in FIG. 5, the unevenness 5 is provided in parallel with the traveling direction (see the white arrow), and the sipes 6 are provided in the direction orthogonal to this and without penetrating the width direction of the block 3. ing. Further, in the fifth embodiment shown in (d), the unevenness 5 is inclined with respect to the traveling direction (see the white arrow) and has no sipe. Further, in the sixth embodiment shown in (e), the unevenness 5 is not a groove-like long one but is formed as an assembly of small protrusions.

As described above, in the present invention, it is possible to appropriately change the shape, orientation, number, size, etc. of the unevenness 5, as well as the combination with the sipe 6, rough surface unevenness, and the like. Of course, the use as the tire 1 (applied vehicle type, running road surface, etc.) is not limited.

[0020]

The present invention is provided with the above-mentioned structure, and the surface of the block (the surface that contacts the road surface) is
By providing fine unevenness (smaller than the block and larger than the rough surface unevenness), the roughening of the block surface causes the water film rupture effect on the tire tread surface on the frozen road surface and the snow-covered road surface and familiarity with the road surface unevenness. Due to the effect, more excellent running applicability can be obtained.

Needless to say, if the block surface is roughened or the sipes are used in combination, a synergistic effect with them can be expected, and it is possible to cope with a wide range of road surface conditions from a mirror-frozen road surface to a snowy road surface. , Effective.

[Brief description of drawings]

1 is a cross-sectional perspective view showing a main part of a tire according to the present invention (corresponding to an enlarged view of part A in FIG. 2).

FIG. 2 is an overall view for explaining the positioning of main parts in the present invention.

FIG. 3 is an enlarged side sectional view of a block (corresponding to an enlarged sectional view taken along line BB in FIG. 2).

FIG. 4 is a graph showing the relationship between the direction of unevenness and the road surface frictional force.

FIG. 5 is a diagram showing a situation of application to a road surface due to various irregularities.

FIG. 6 is a perspective view showing main parts of second to sixth embodiments according to the present invention.

[Explanation of symbols]

 1 tire 2 tread surface 3 block 5 unevenness 6 sipes

Claims (3)

[Claims] 1. A pneumatic tire having a block pattern on a tread surface (2), characterized in that each block (3) is provided with fine irregularities (5) on the surface thereof. 2. The block (3) comprises a foreign substance (8).
The pneumatic tire according to claim 1, wherein the surface is formed to be a rough surface by using a contained rubber material or a foamable rubber material or by embossing during molding. 3. The pneumatic tire according to claim 1, wherein the block (3) is provided with a sipe (6).