JPH06270609A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To provide a pneumatic tire equipped with a tread pattern which can exert a high wet operation performance under condition with low noise and high maneuvering stability. CONSTITUTION:A pneumatic concerned is equipped with a center circumferentially running groove 1 in the central area of the tread and a number of center slant groove groups positioned as pinching the center groove 1, wherein the pattern is such that center ribs 6 and side lugs 7 are formed by arranging a number of crosswise grooves 4, 5 which are in communication at one end with the center slant grooves and extend in curvature from the central region to each side region.

Description

Detailed Description of the Invention

[0001]

[Industrial application] High-performance tires, that is, pneumatic tires that have been improved to fit in high-performance high-performance vehicles that have improved running performance to the highest level without sacrificing major functions Therefore, it is intended to propose a pneumatic tire that embodies a drastic concept of a tread pattern that realizes high wet performance.

[0002]

2. Description of the Related Art A pattern in which straight ribs are arranged in the central region of the tread is generally used in order to improve stability when traveling straight ahead and reduce pattern noise.

In order to improve the hydroplaning resistance of the wet performance, for example, Japanese Patent Laid-Open No. 4-19020 is known.
It is generally known that it is effective to increase the groove area (negative) as shown in the publication, and it is effective to increase the negative in the central area of the tread from the ground contact shape and the distribution of contact pressure. This is because the contact pressure is higher and the contact length is longer in the central region of the tread than in other regions while the tire is running.

[0004]

It is effective in terms of wet drainage to dispose a straight main groove in the central region of the tread in addition to the normal directional inclined groove, but noise reduction and straight running stability are effective. The inventors of the present invention have found that by arranging ribs on both sides of the ribs, and in this case, by increasing the negative on the outside of the ribs, noise and straight running stability are ensured and the wet performance is further improved. It was discovered as a result of the experimental study. Therefore, it is an object of the present invention to provide a pneumatic tire having a tread pattern that can advantageously improve high wet performance without sacrificing other performance.

[0005]

SUMMARY OF THE INVENTION The present invention has a tread in a toroidal shape between a pair of sidewalls and a tread that is in contact with the road surface. The tread has a tread half of the tread half width from the equatorial plane of the tire. A center circumferential groove 1 that extends straight along the circumference of the tread in the central area that is divided into both areas on the outside of the circumferential line that extends toward 2
The center circumferential groove 1 is sandwiched and a group of center oblique grooves 3 formed of a pair of oblique intermittent drain lines facing each other and having convexities or small curvatures along the center circumferential groove 1 are gradually arranged.
A group of a plurality of transverse grooves 4 and 5 that communicate with each other at each of the center oblique grooves 3 and extend in a curved manner from the central region to both side regions on the side of the sidewall while the other end is open is arranged. A tread including a pair of center ribs 6 divided into groups of center oblique grooves 3 on both sides of the circumferential groove 1, and a large number of side lugs 7 divided into groups of center oblique grooves 3 and groups of transverse grooves 4 and 5. A pneumatic tire characterized by having land portions, wherein side lugs (7) are divided by at least one side circumferential groove (2) extending straight along the circumference of the tread in both side areas close to the central area. The side lug 7 is subdivided by the sipe 8 extending along the transverse grooves 4 and 5 which divide the block 7a and 7b, and divides the lug width into substantially equal parts to reach the center circumferential groove 1. What Lying, that imaginary extension of the center Hasumizo 3 and transverse grooves 4 and 5 are directional pattern by grooves sequences converging in the central circumferential groove 1 and the center Hasumizo 3
And the inclinations α and β of the chord consisting of the line segment connecting the groove ends of the transverse grooves 4 and 5 with respect to the tire equatorial plane are 5 to 30 °, respectively.
It is preferably 30 to 90 °.

1, 2, 3 and 4 exemplify tread patterns according to the present invention. These tread patterns are applied, the basic configuration of a pneumatic tire is a pair of sidewalls and a crown portion striding in a toroidal shape between them, and a bead core embedded in the bead portion on the inner peripheral edge of the sidewall portion. Multiple layers of mutually parallel arranged cords reinforced by a carcass of radial structure consisting of plies of cords wound back around and crossed around the crown at a small angle to the plane normally containing its central circumference. In the arrangement of the belts to be laminated, the tread provided to the crown portion is reinforced, and further, a reinforcing member may be appropriately disposed on the ply end of the bead portion, the belt end of the crown portion, or the outer circumference thereof. Therefore, the illustration of the details of the structure is omitted, and only the pattern is illustrated in the developed plane of the main part.

In each drawing, 1 is a center circumferential groove, 2 is a side circumferential groove, 3 is a center oblique groove, 4 and 5 are transverse grooves, and 6
Is a pair of center ribs divided by a center circumferential groove and a group of center oblique grooves 3, and 7 is a group of center oblique grooves 3 and transverse grooves 4, 5
The side lugs 7a and 7b are divided by the group (1), and are formed by dividing the side lug 7 by the side circumferential groove 2. The center rib 6 and the side lug 7 function as a tread land portion.

In FIGS. 1, 2 and 4, the transverse grooves 4, 5 are
While it extends from the middle point of the length of the center slant groove 3 and the start end near the center groove 1 to the end portion which opens to the side of the sidewall, the transverse grooves 4 and 5 are the total length of the center slant groove 3 in FIG. Approximately one-third of the center slant groove 3 is extended in the same way from the groove end, and in this case, the center slant groove 3 has an intermittent arrangement. Although not provided, they may be connected by a connecting groove.

Here, the tread T is provided with a toroidal contact between a pair of sidewalls (not shown) in a crown shape, and a contact portion with the road surface is prepared at the crown portion. The center area of the tread T is the ground contact width of the tread T. Of 1/2 (hereinafter referred to as "half width of tread", indicated by W) is approximately 1 /
2 refers to a band-shaped region virtually divided by the tread circumferences c and c (see FIG. 1) that separate the two from the tire equator to the left and right, and both sides up to the width ends e of the tread T on both sides thereof. Form a tread T with the zone. On the tread T, a center circumferential groove 1 extending straightly around the center region thereof, and a distance along the center circumferential groove 1 which sandwiches the center circumferential groove 1 and has a convex curvature facing each other, gradually changes. While arranging a group of center oblique grooves 3 formed by a pair of oblique intermittent rows, while communicating with each of the center oblique grooves 3 at one end and opening the other end laterally of the sidewall from the central region to both side regions Arrange a group of a number of transverse grooves 4, 5 that extend in a curved manner. 1 to 4, in any case, the tread 1
The side lugs 7 are provided with at least one side circumferential groove 2 extending straight along the circumference of the tread 1 in both side regions close to the central region of the side lug 7, whereby the side lugs 7 are blocked by the blocks 7a.
And 7b.

In the case of FIGS. 1 and 3, the center oblique grooves 1 sandwich the center oblique grooves 2 in different staggered arrangements, whereas in FIG. Be in line. As shown in FIG. 4, the side lug 7 may be subdivided by the sipe 8 extending along the transverse grooves 4 and 5 that divide the side lug to divide the lug width into two and reach the center circumferential groove 1.

In the above description, the imaginary extension of the center oblique groove 3 and the transverse grooves 4 and 5 is a directional pattern due to the groove arrangement that converges on the central circumferential groove 1, and the center oblique groove 3
And the cross grooves 4 and 5 have inclinations α and β of 5 to 30 with respect to the tire equator of the string formed of line segments connecting the groove ends.
30 ° to 90 °.

[0012]

In a general high-performance system, that is, in the tread pattern of a pneumatic tire having an aspect ratio of 65% or less, in order to maintain sufficient wet performance, the center circumferential groove 1 that extends straight around the tread and this is used. It is necessary to include a group of center oblique grooves 3 on both sides.

Since it is effective to increase the groove area particularly in the tire central area from the ground contact shape and the distribution of the contact pressure, the group of the center circumferential groove 1 and the center oblique groove 3 is arranged in the central area of the tread T. , Crossing grooves 4, 5 extending continuously from the central area to both areas to enable drainage within the surface of the tread T
The most effective combination is the combination of At this time, if the transverse grooves 4 and 5 are connected to the center circumferential groove 1 in the central region,
Since water flowing straight through the center circumferential groove causes turbulence due to the opening of the transverse groove, drainage is not performed efficiently,
It is necessary to separate the water channel flowing from the central region of the tread along the transverse grooves 4 and 5 from the central region of the tread from the center circumferential groove 1.

On the other hand, in order to ensure straight running stability especially at high speed, it is also necessary to have straight center ribs 6 extending along the circumference of the tread T in the central region thereof.
In consideration of the above-mentioned wet drainage, the center circumferential groove 1 is arranged in the central region of the tread T, and the center ribs are arranged on both sides thereof. However, in order to secure lateral rigidity of the rib, it is usually necessary to arrange a circumferential groove that separates the outer side of the rib at a position away from the central region of the tread T. In that case, the rib is thickened and the tread central portion is increased. Drainage capacity of the

Therefore, by arranging the group of center oblique grooves 3 so as to form a zigzag-shaped peripheral groove on the outer side of the ribs on both sides of the center peripheral groove 1, the rigidity of the ribs is ensured, and at the same time, the negative is secured. It is possible to realize more efficient wettability. In particular, it is necessary to provide the center slant groove 3 having a considerably small inclination angle in the central region of the tread T for wet drainage. The center oblique groove 3 is also effective in reducing noise due to air column resonance, which is a drawback of the straight main groove.

Here, the center oblique grooves 3 forming a zigzag arrangement are formed in a curve having a curvature in which the angle of the tangent to the equatorial direction of the tire gradually decreases toward the center circumferential groove 1 for wet drainage. It matches the direction of the drainage stream to the front and side of the ground contact due to the rotation of the tire, producing good results. Further, the effect becomes more remarkable by providing so-called directionality in which the inclination directions are opposite to each other with respect to the equatorial plane of the tire.

[0017]

EXAMPLES The present invention was applied to a tire having specifications of PSR 225 / 50R16 with a tread width of 2 W: 200 mm and a ground contact length L of 120 mm as follows.

Invention Pattern A (FIG. 1)

[Table 1]

Invention Pattern B (FIG. 2)

[Table 2]

Invention Pattern C (FIG. 3)

[Table 3]

Invention Pattern D (FIG. 4)

[Table 4]

The conventional pattern shown in FIG. 5 is different from the present invention only in the pattern, and the other tires have the same characteristics as the invention tire. The comparative tire having the same result has a performance of 100, wet noise, pattern noise, and dryness. The following table shows the test results of steering stability.

[Table 5]

[0023]

According to the present invention, it is possible to remarkably contribute to the improvement of the wet performance while improving the pattern noise and the dry steering stability.

[Brief description of drawings]

FIG. 1 is a partially developed plan view of a tread pattern showing an embodiment of the present invention,

2 is a similar plan view of another embodiment, FIG.

FIG. 3 is a similar plan view of another embodiment,

FIG. 4 is a similar plan view of a modified embodiment,

FIG. 5 is a partially developed plan view of a conventional pattern.

[Explanation of symbols]

 1 Center Circumferential Groove 2 Side Circumferential Groove 3 Center Oblique Groove 4 Cross Main Groove 5 Cross Main Groove 6 Center Rib 7 Side Lug

Claims (5)

[Claims] 1. A tread having a tread which is in contact with a road surface in a crown portion which extends in a toroidal shape between a pair of sidewalls, and which has a circumferential line extending from a tire equatorial plane to a half of the tread half width. A center circumferential groove 1 that extends straight along the circumference of the tread and a center circumferential groove 1 that sandwiches the center circumferential groove 1 and faces each other with a small curvature that is convex toward each other in the central area that is divided from both outer areas. A center slanted groove 3 formed by a pair of slanted intermittent discharge lines whose intervals along the circumferential groove 1 gradually change.
And a plurality of transverse grooves 4 and 5 which communicate with each of the center oblique grooves 3 at one end and extend from the central region to both regions on the side of the sidewall while the other end is open. Groups of center ribs 3 are arranged on both sides of the center circumferential groove 1 and are divided by a pair of center ribs 6 and a group of center diagonal grooves 3 and groups of transverse grooves 4 and 5. A pneumatic tire having a tread land portion including a large number of side lugs 7. 2. The side lug 7 is in the form of blocks 7a, 7b divided by at least one side circumferential groove 2 extending straight along the circumference of the tread in both side regions close to the central region. Pneumatic tires listed. 3. The side lug 7 is subdivided by the sipe 8 extending along the transverse grooves 4 and 5 that divide the side lug 7 until it reaches the center circumferential groove 1 by effectively dividing the lug width into two equal parts. The pneumatic tire described in 1 or 2. 4. The pneumatic tire according to claim 1, wherein the imaginary extension of the center oblique groove 3 and the transverse grooves 4, 5 is a directional pattern formed by a groove array that converges on the central circumferential groove 1. 5. The inclination α, β of the chord consisting of a line segment connecting the groove ends of the center oblique groove 3 and the transverse grooves 4, 5 with respect to the tire equatorial plane is 5-30 °, 30-90 °, respectively. The pneumatic tire according to any one of 1 to 4.