JPH02182505A - Tread pattern of automotive tire - Google Patents

Abstract

PURPOSE:To increase steering safety by providing roundnesses of the respective ly specified different radius of curvature at the corner sections of a block, where main grooves and auxiliary grooves intersect with each other, and the edge sections where a tread and main grooves or auxiliary grooves intersect with each other. CONSTITUTION:Blocks 3 are formed on a tread surface section by main grooves 1 in the circumferential direction of a tire and auxiliary grooves 2 intersecting with the main grooves at right angle or aslant. In the cross-section of the tread surface section, the edge section 7 of the block 3 are formed by the ground- contact surface 5 of the block 3 and the wall surfaces 6 of the main groove 1 or auxiliary groove 2 intersecting with the ground-contact surface 5. In the above tread pattern, the corner section 4 of the blocks is rounded at a radius of curvature of 2 to 5mm on the ground-contact surface 5 in any cross-section in parallel to that surface. The edge section 7 are also rounded at a radius of curvature of 1.5 to 2.5mm in a cross-section perpendicular to the ridge of the block. Thus the rigidity of the whole block 3 can be uniformed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high-performance automobile tire that is used in circuit races and the like and has high turning performance and excellent handling stability.

[Conventional technology]

When a high-performance vehicle turns on a road surface with high road friction,
In the block of the installed tire, the tread rubber wears out significantly in areas where a large load is applied, creating a level difference between the area and the area where a relatively small load is applied, resulting in a so-called toe-and-heel wear condition. The block in this state has poor ground contact, and wear progresses even faster in the heavily loaded areas, and the edges of the lightly loaded areas collapse into the adjacent grooves, reducing the ground contact pressure and weakening the frictional force with the road surface. Adversely affects stability.

As a means to solve these problems, a method has been attempted in which the inclination angles of the side walls of the front, rear, left, and right grooves of the tread block are varied in accordance with the magnitude of the load on the portion of the block that is in contact with the grooves.

Also used is a so-called semi-flick pattern that suppresses toe-and-heel wear by reducing the groove area.

[Problem that the invention seeks to solve]

When the direction of rotation of the tire is reversed, the direction in which toe-and-heel wear occurs is reversed, so the angle of inclination of the sidewalls of the grooves around the tread block should be adjusted according to the magnitude of the load on the part of the block that is in contact with the grooves. The changing method can only be used for tires with directional properties in which the rotational direction of the tire is limited to a fixed direction.

In the case of a semi-flick pattern, the drainage performance deteriorates due to a decrease in the groove area ratio, that is, the void ratio, and the steering stability on wet road surfaces deteriorates.

Therefore, an object of the present invention is to provide a tire that prevents toe-and-heel wear, allows the rotation direction of the tire to be arbitrarily selected, and has excellent handling stability on wet roads.

[Means for solving problems]

In order to achieve the above object, the inventor of the present invention has conducted intensive research and found that by reinforcing the parts of the tread block with low rigidity, wear in the high load parts of the block can be suppressed, and groove blocks in the low load parts can be suppressed. In other words, the grooves around the block intersect at acute angles in the plan view of the tread pattern.
The rigidity of the sharp corners of the block and the edge of the groove where the ground plane of the block intersects the inner side surface of the groove in the cross-sectional view is particularly low, so by rounding these corners and edges, the rigidity of the block We discovered that it is possible to equalize the overall rigidity, resulting in more uniform wear, improved ground contact, and increased steering stability.
The present invention has now been completed.

That is, the present invention provides an automobile tire having a block pattern in a tread surface portion consisting of a main groove extending in the tire circumferential direction and a sub-groove that intersects with the main groove. The corners of the block should be rounded with a radius of curvature of 2 to 5 mm on the ground plane or any cross section parallel to this, and the ground plane of each block should intersect with the wall surface of the main groove or minor groove surrounding the block. A radius of curvature of 1.5 to 2°5ff is applied to the edge of the block produced by
The gist is a tread pattern of an automobile tire characterized by having a roundness of iI11.

Next, the content of the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a developed view of the tread 1<turn of the automobile tire of the present invention. In the conventional tread pattern of automobile tires, as shown in Fig. 2, blocks (3) are surrounded by a main groove (1) in the circumferential direction of the tire and sub-grooves (2) that intersect at right angles or diagonally with the main groove (1). The corner portion (4) has an acute or obtuse angle depending on the intersection angle between the main groove (1) and the sub-groove (2). In addition, in the cross-section of this tread, as shown in the cross-sectional view of Fig. 3, a block is formed when the ground plane (5) of the block (3) intersects with the wall surface (6) of the main groove (1) or the sub-groove (2). The edge portion (7) of (3) is formed with a sharp ridge line.

In the tread pattern of the present invention, as shown in FIG.
The corner part (4) of block (3) is
ground plane (5) or block (3) to its ground plane (5)
In each section cut parallel to , the corners are rounded. The radius of curvature of the roundness is 2-5 m11.

Figure 4 is an enlarged view of the A-A cross section in Figure 1, showing the contact surface (5) of the block (3) and the wall surface (6) of the main groove (1).
The edge portion (7) formed when the two intersect is rounded. The radius of curvature of the roundness is 1.5-2.5 mm.

[Effect]

According to the tread pattern of the automobile tire of the present invention,
Corner part (4) and edge part (7) of block (3)
By giving roundness to the block (3), there are no low-rigidity parts such as the sharp tips of the corner parts (4) and edge parts (7), and the rigidity of the entire block (3) is made uniform. This prevents the edge portion (7) from collapsing into the adjacent groove, making the ground pressure of the block (3) uniform over the entire ground contact surface, resulting in uniform wear, improving the tread's ground contact, and improving maneuverability. Increased stability.

Furthermore, in the tread pattern of the present invention, since the void ratio is not reduced, drainage performance is not adversely affected, and high steering stability is maintained even on wet road surfaces.

〔Example〕

A tire with a tire size of 195150R1581V having the tread pattern of the present invention shown in FIG. 1 and a tire of the same size with a conventional tread pattern shown in FIG. Driving tests were conducted in dry and wet conditions. The results are expressed as an index with the conventional tire set as 100, and are shown in Table 1. The smaller the index, the better.

The radius of curvature of the corner portion (4) of the tire of the present invention used in this test was 3 mm, and the radius of curvature of the edge portion [7] was 1°5.
This is proof.

FIG. 1 Next, in the automobile tire of the present invention having the same size as above and the tread pattern shown in FIG. 1, when the radius of curvature of the corner portion (4) of the block (3) is changed,
) The time required to run the circuit was measured when the radius of curvature was changed. The results are shown in FIGS. 5 and 6. The shorter the required time, the better.

According to this result, if the radius of curvature of the corner portion (4) is too large, the contact area with the road surface will be reduced, resulting in poor maneuverability on dry roads, and if it is too small, a portion with low rigidity will result.
Maneuvering performance on dry roads deteriorates.

In addition, if the radius of curvature of the edge portion (7) is too large, the contact area with the road surface will decrease, resulting in poor maneuverability on dry roads, and on wet roads, water film will easily enter between the tire and the road surface. Maneuvering performance on wet roads deteriorates. On the other hand, if it is too small, the rigidity of the edge portion (7) will decrease and the maneuverability on dry roads will decrease.

〔Effect of the invention〕

According to the tread pattern of the automobile tire of the present invention,
It prevents toe-and-heel wear of the tread, improves steering stability on dry and wet roads, and enables excellent handling performance under harsh usage conditions such as circuit races.

[Brief explanation of the drawing]

FIG. 1 is a developed view of the tread pattern of the automobile tire of the present invention, FIG. 2 is a developed view of the tread pattern of a conventional tire, FIG. 3 is a sectional view taken along line B-B in FIG. 2, and FIG. The A-A sectional view in Figure 1, Figures 5 and 6 show the case where the radius of curvature of the corner part (4) of the tire of the tread pattern of the present invention is changed, and the radius of curvature of the edge part (7) is changed, respectively. It is a graph showing the time required for circuit driving when the time is changed. (1) Main groove, (2) Minor groove, (3)
Block, (4) corner, (5) ground plane, (6) wall, (7) edge. Fig. 2 Fig. 5 2 1-1-1000-Year-Old → Adventure” Figure 6 1.52.5 1.1. ν・Valve curved falcon diameter bullet m9 Fig. 1゛ Main groove sub-groove block 4 Corner ground plane 6 Wall edge portion Fig. 3

Claims (1)

[Claims] (1) In an automobile tire having a block pattern in the tread surface portion consisting of a main groove extending in the tire circumferential direction and a sub-groove that intersects with the main groove, the corner of the block is formed when the wall surface of the main groove intersects with the wall surface of the sub-groove. In the ground plane or any cross section parallel to this, the radius of curvature is 2 to 5.
A radius of curvature of 1 mm is provided at the edge of each block where the ground plane of each block intersects with the wall surface of the main groove or sub-groove surrounding the block, in a cross section perpendicular to the ridgeline of the edge. A tread pattern for an automobile tire characterized by having a roundness of .5 to 2.5 mm.