JPH01254407A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To improve the braking performance on snow and ice, traction performance and a cornering property by providing circumferential (fine grooves) and radial calves and forming a tread with a block pattern consisting of blocks in which at least one end of each of the calves is connected to the outside thereof. CONSTITUTION:A block pattern consisting of main grooves 1, lateral grooves 2, and blocks 3 formed by both grooves 1, 2 is formed on a tread surface. A plurality of radial calves 4a, 4a... and a plurality of circumferential calves 4b, 4b... are provided on each block 3 passing through the whole block up to the sides of each block. In this case, it is desirable that only one end of each circumferential calf 4b is connected to the outside of the block 3 with the connecting ends of mutually adjacent calves alternately coming to the opposite-side block ends. The calves in the circumferential direction of tire chiefly contribute to the improvement of a cornering property which is a driving stability against external force at the time of cornering.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire that improves not only braking performance and traction performance on icy and snowy roads but also cornering performance.

[Prior art]

-g All-weather tires and tires for icy and snowy roads have a tread surface composed of a block pattern to enhance braking and traction performance on icy and snowy roads. It has grooves cut into it. However, although this conventional tire exhibits an acceptable level of braking performance and traction performance in the traveling direction, its cornering performance during cornering is still insufficient, and there has been a strong demand for reinforcement of the negative layer.

[Purpose of the invention]

The purpose of the present invention is to improve braking performance and traction performance on icy and snowy roads in a tire having a block pattern.
Furthermore, it is an object of the present invention to provide a pneumatic tire that further improves cornering performance.

[Structure of the invention]

In order to achieve the above object, the pneumatic tire of the present invention includes:
The trend surface is mainly composed of a block pattern, and the blocks constituting this block pattern are provided with a kerf in the circumferential direction of the tire and a kerf in the radial direction of the tire, and kerfs in both directions. The block is characterized in that at least one end thereof is provided so as to communicate with the outside of the block.

In the present invention, the pneumatic tire may be either a radial tire or a bias tire. More preferably, it is applied to radial tires.

In the present invention, the block pattern refers to a tread surface in which independent ground-contacting parts (ridges) are clearly divided by non-ground-contacting parts (grooves), forming a large number of blocks. This block pattern forms frost pillars of compacted snow between adjacent blocks when driving on icy roads, and by utilizing the shearing force of the frost pillars, it exhibits higher braking and traction performance than other tread patterns. It is now possible to do so.

In the present invention, such a block pattern is mainly formed on the tread surface, but other patterns may be supplementarily added and used in combination.

That is, although this block pattern is used as the main pattern, it is also possible to use a so-called rib block pattern in which, for example, ribs extending in a band shape in the tire radial direction are combined with this block pattern.

In the present invention, the kerf provided in the block refers to a cut groove having a narrow groove width, and it is necessary to provide it not only in the radial direction of the tire but also in the circumferential direction of the tire. The size of the kerf is preferably such that the width is within 1 mm and the depth is 0.6 times or more and equal to or less than the main groove. The kerfs in both the tire radial direction and the tire circumferential direction are arranged in a relationship that intersects with each other on the block surface, and an arbitrary number of kerfs are provided depending on the size of each block. That is, when the block width is narrow, one wire is provided, and when the block width is wide, multiple wires are provided.

The cuffs provided in the tire radial direction and the tire circumferential direction must be provided so that at least one end thereof communicates with the outside of the block. Most preferably, both ends of the kerf in the tire radial direction communicate with the outside of the block, as in the embodiment shown in FIG. 2 described later, but only one end of the kerf in the tire circumferential direction communicates with the outside of the block.
The other end is to be within the block.

Furthermore, the kerfs in the circumferential direction of the tire are arranged so that adjacent kerfs alternately communicate with the outside of the block on the opposite side (see Figure 2). This makes it possible to improve the required braking performance and traction performance without reducing block rigidity, and to most effectively improve cornering performance.

In the present invention, the kerf provided in the tire radial direction facilitates deformation of the block against external force applied in the tire circumferential direction. Therefore, this increases the followability of the block surface to the road surface and maintains a large contact area, and also increases the edge effect of the block end on the road surface. Therefore, braking performance and traction performance in the tire traveling direction are improved. On the other hand, the kerf provided in the tire circumferential direction facilitates deformation of the block against external force applied in the tire radial direction.

Therefore, it increases the followability of the block surface to the road surface and maintains a large contact area.
To enhance the edge effect of the block end on the road surface. Therefore, cornering force during cornering is increased and cornering performance is improved.

Furthermore, in the present invention, the kerf is provided not only in the radial direction of the tire but also in the circumferential direction of the tire so as to intersect with the kerf, so that the block deformation effects of the kerfs in both directions are synergistic, and the kerf is provided in the tire radial direction. The road following ability of the block can be further improved compared to a conventional tire provided with a kerf. Therefore, the tire of the present invention has much improved braking performance and traction performance compared to the conventional tire.

Furthermore, in the present invention, the groove depths of the kerfs provided in the tire radial direction and the tire circumferential direction are preferably not the same throughout the block, but the groove depth at the end of the block is shallower than that at the center of the block. It is better to do it naturally. With such a groove depth configuration, the rigidity of the end of the block can be increased, thereby making it possible to prevent the occurrence of chipping at the end of the block.

Hereinafter, the present invention will be specifically explained with reference to the drawings.

FIG. 1 shows an example of a block pattern (tread pattern) provided in the pneumatic tire of the present invention.
Arrow T is the tire circumferential direction. In FIG. 1, the tread surface has a plurality of main grooves 1.
-.-11 are provided in a zigzag pattern. A large number of lateral grooves 2, -, 2 extending in the tire width direction are provided at predetermined intervals between the adjacent main grooves 1.1, and by providing the lateral grooves 2, the main grooves 1 and 2 are separated. A large number of blocks 3°..., 3 are formed surrounded by.

Each block 3 has a plurality of kerfs 4a, . . . , 4a extending in the tire radial direction, and a plurality of kerfs 4b, . It is provided. That is, both ends of the former kerf 4a pass through the main leads 1.1 on both the left and right sides, and both ends of the latter kerf 4b pass through the lateral grooves 2.2 on both the front and rear sides, respectively.

The blocks 3 in this embodiment have different shapes between those provided on both shoulders and the center, and the former has a larger surface area than the latter.

However, these shapes and surface areas may be arbitrarily changed depending on the size of the tire and the nature of the ice and snow. The most fundamental principle can be represented by a basic example as shown in FIG. Particularly preferably, both ends of the tire radial direction cuff 4a communicate with the outside of the block 3;
It is preferable that only one end of b communicates with the outside of the block 3, and that the communicating ends are arranged alternately between adjacent kerfs so as to face opposite block ends.

The kerf 4a + 4b provided on such a block 3 is preferably made so that the groove depth at the block end is shallower than that at the center of the block, as shown in FIGS. 3 and 4. Good. This makes it possible to prevent the phenomenon of chipping at the end of the block, which is likely to occur due to the provision of the kerf. Also, this change in groove depth is
It may be a gradual change in a curved line as shown in the figure, but
It may also change stepwise as shown in FIG.

In the tire of the present invention having the above configuration, the tire radial direction kerf and the tire circumferential direction kerf provided on the block surface are as follows:
Each makes the deformation of the block easier, thereby improving the road followability of the block surface.The former kerf mainly improves braking performance and traction performance in the direction of travel, while the latter kerf mainly improves lateral external forces during cornering. It improves cornering performance, which is steering stability. Moreover, by providing the kerfs in a relationship that intersects with each other in both directions, the synergistic effect of the kerfs further improves the road followability of the block surface and the edge effect on the road surface.
Therefore, braking performance and traction performance can be further enhanced compared to conventional tires in which the kerf is formed only in one direction in the tire radial direction.

The effects of the present invention described above can be easily confirmed by the following experiment.

That is, a test piece 30 of the present invention as shown in FIG. 6, which simulates the blocks of a block pattern, and a conventional test piece 300 as shown in FIG. 7 were prepared. Each specimen has a width x length x thickness of 25 x 20 x 12 mm.
The test piece 30 of the present invention has a groove width of 0.
゜3mm, depth 81 mutually intersecting kerfs 4 a+4
b was established. Furthermore, the test piece 300 of the conventional example did not have the kerf 4b from the test piece 30 of the present invention.

These two types of test pieces were tested at an ice temperature of -2°C using a friction tester (manufactured by Sunny Lab) using the rotating disk method.
Temperature -1℃, initial speed 40km/hr, load approx. 1kg
/cm'', the friction force was measured in two directions: when rotating in the A direction and when rotating in the B direction, corresponding to the tire circumferential direction and the tire width direction, respectively.

When the results were expressed as an index with the conventional example set as 100, the results were as shown in the following table.

From the results in this table, the test piece according to the present invention has improved friction force in both the tire circumferential direction (A direction) and the radial direction (B direction) compared to the conventional test piece. Therefore, a pneumatic tire having a block pattern based on the test piece of the present invention can further improve braking performance, traction performance, and even cornering performance compared to conventional tires.

〔Effect of the invention〕

As described above, the pneumatic tire of the present invention is provided with a block pattern, and the block has a kerf in the tire radial direction and a kerf in the tire circumferential direction, and the ends of the kerfs in both directions are placed outside of the block. Since it is provided so as to pass through the block, it allows the block to deform with high road surface followability, and provides a high edge effect, not only when external force is applied in the tire circumferential direction, but also when external force is applied in the tire radial direction. Can be done. Therefore, such deformation not only enhances braking performance and traction performance on icy and snowy roads, but also improves cornering performance, which was insufficient with conventional tires. Furthermore, the braking performance and traction performance can be further improved compared to conventional tires due to the synergistic effect of the kerfs provided in both directions.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an example of a block pattern provided in a pneumatic tire of the present invention, FIG. 2 is a plan view showing a basic example of blocks in the same block pattern, and FIG. 4 is a view taken along the line IV-IV in FIG. 2. FIG. 5 is a sectional view showing another embodiment corresponding to FIG. 3. FIGS. 6 and 7 are plan views of the simulator test piece. 1... Main groove, 2... Lateral groove, 3... Pro-tsuku, 4
a. 4b...Calf. Agent Patent Attorney Nobuo Ogawa −

Claims (1)

[Claims] The tread surface is mainly composed of block patterns,
A pneumatic tire in which a block constituting the block pattern is provided with a kerf in the tire circumferential direction and a kerf in the tire radial direction such that at least one end of each kerf in both directions communicates with the outside of the block.