JPH026645B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a tread structure for a vehicle tire.

(Prior Art) A pneumatic tire in which longitudinal and lateral grooves are formed in the tread portion, the lateral grooves are made to have an angle, and the area ratio of the grooves and the blocks formed by the grooves is taken into account, for example, No. 140604 has been proposed (conventional example 1).

Further, as a pneumatic tire having a tread pattern consisting of main grooves extending diagonally from the circumferential center position of the tread portion toward the tread ends in a mesh pattern, and groups of blocks separated by these main grooves. For example, Japanese Patent Publication No. 58-2846 has been proposed (Conventional Example 2).

(Problems to be Solved by the Invention) Although these conventional examples 1 and 2 are recognized to have a certain degree of effectiveness in terms of wet performance and dry performance, they have the following problems.

In other words, in conventional example 1, a center vertical groove is formed linearly in the tire circumferential direction at the center of the tread, which reduces the ground contact area at the center and makes it difficult to respond to small steering angles with the steering wheel. There is also a problem that the water film cutting function on the road surface cannot be expected.

Furthermore, in the conventional example 1, a vertical rib is formed at the center of the tread, but since the ribs have a so-called zigzag shape rather than a straight line, the center part has a vertical rib. There is a problem that the drainage performance is poor, and furthermore, the water film cutting function cannot be expected, resulting in a decrease in wet performance.

In addition, conventional example 2 has a so-called diamond-shaped block in the center of the tread, and although it can ensure grip on dry roads, the lateral rigidity (in the axial direction of the tire) is weak because the block is diamond-shaped. Because of this, the response at small steering angles is poor, and the difference in lateral stiffness between individual blocks is extreme due to the rhombus shape, which causes uneven wear and is a problem in terms of durability. It was hot.

Furthermore, in Conventional Example 2, the main groove is mesh-shaped, resulting in poor drainage performance and reduced wet performance, and the diamond-shaped blocks are arranged at intervals in the circumferential direction. As a result, there was a problem that the noise became intense.

In view of the problems of the prior art, the present invention provides a tread structure consisting of grooves formed in the tire tread portion and blocks defined by the grooves, and by giving directionality to the grooves, particularly the lateral grooves, The purpose is to raise the limits of dry and wet performance, improve high-speed straight-line stability, improve wet grip, straight-line stability, and disperse noise.

(Means for Solving the Problems) According to the present invention, a plurality of vertical grooves are formed on the outer surface side of the tread portion of a tire and are continuous along the entire circumferential length at intervals in the tread width direction, and these vertical grooves are A plurality of lateral grooves communicating in the width direction intersect at an angle with respect to the tread center and are arranged at intervals in the circumferential direction of the tire, forming a block defined by each of the longitudinal grooves and the lateral grooves. In order to achieve the above-mentioned purpose, the following technical measures are taken in a vehicle tire tread structure in which the total area of the ground contact part of the block is large and the total area of vertical grooves and lateral grooves is small. .

The blocks include a rib-shaped center block 21 disposed on the center of the tread portion 14 and formed over the entire circumferential direction, and a rib-shaped center block 21 arranged circumferentially on the outside of the center block 21 in the tread width direction. It consists of both side blocks 26 formed through vertical grooves 23, and both shoulder blocks 27 formed on the outside in the tread width direction of both side blocks 26 through straight vertical grooves 24 in the circumferential direction. , the lateral grooves 22, 25, and 28 are left and right center lateral grooves 22 formed on both sides of the center block 21 so as to cross each other at an angle with respect to the center of the tread, and to be out of phase with each other in the circumferential direction. Side lateral grooves 2 are formed extending substantially linearly from each center lateral groove 22 to both outer sides in the tread width direction.
5 and a shoulder lateral groove 28, and the vertical groove 2
3, 24, side horizontal groove 25, shoulder horizontal groove 28
The left and right side blocks 26 and the shoulder blocks 27 are characterized by being substantially symmetrical with respect to the center of the tread and being shifted in phase in the circumferential direction.

(Embodiments and Effects) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a cross section of a tire having a tread pattern according to the present invention, and 10 is a tire body, which includes a bead portion 11, a sidewall portion 12, a shoulder portion 13, and a tread portion 14.
The overall shape is toroidal.

A bead wire 15 is attached to each of the bead portions 11.
A carcass ply 16 is wound around the bead wire 15, and the carcass ply 16 is a high modulus 2 polyester carcass, and the winding terminal 16A is located closer to the tread portion than the maximum width portion L of the tire. It has a so-called high turn-up configuration.

17 is an inside reinforcement, which extends from the outer circumferential surface of the bead handle (wire) to near the maximum width part L of the tire, and 18 is an ultra-hard filler, which is used for the above-mentioned high turn up and inside reinforcement. 17 and the filler 18 improve the lateral rigidity of the tire, contributing to increasing steering stability.

19 is a steel belt layer, 20 is a nylon belt layer, and the steel belt layer 19 is made by twisting two steel cores 19A together and twisting seven steel outer members 19B around them, as shown in FIG. The steel belt layer 19 is wrapped with wires 19C, which are arranged in parallel across the entire width of the tire's tread width to form two layers, an inner and outer layer, which intersect with each other. Two nylon belt layers are fixed on the outside in parallel to each other.

Thereby, since the steel belt layer 19 and the nylon belt layer 20 are fixedly provided over the front surface of the tread portion and the shoulder portion, lifting of the tire can be prevented. In other words, it prevents the outer diameter of the tire from growing due to centrifugal force at high speeds.

The outer surface shape of the tread portion 14 has a radius R ₁ of the center band and a radius R ₂ of the side bands, which is a so-called deal-arc tread design. In this example, R ₁ is
630mm, R ₂ is 317mm, L ₁ is 47mm, L ₂ is 20mm, L ₃ is
It is said to be 67mm, and the shoulder radius is also indicated as R ₃ .

Incidentally, on the outer surface side of the tread portion 14, directional lateral grooves are formed that intersect with the longitudinal grooves in one of the inclination directions of 25 degrees, 45 degrees, and 56 degrees with respect to the tire center line O-O. In addition, a block defined by vertical grooves and horizontal grooves is formed, and each of the vertical grooves has a straight line shape continuous over the entire circumferential direction at intervals in the tread width direction,
The horizontal grooves are arranged at intervals in the circumferential direction to connect the vertical grooves with each other, and the ratio of the block's ground contact area to the groove area is 70% to 30% to improve dry and wet performance. ing.

Each embodiment of the tread structure will be described in detail with reference to FIGS. 3 to 6. Each of these figures is partially developed and shown in plan view, and the center block 21 is located on the tire center line along the entire circumferential direction. On both sides of the center block 21, center lateral grooves 22 having an angle α obliquely intersecting the center of the tread are formed in a so-called zigzag pattern with the phase shifted in the circumferential direction. has been done.

Center vertical grooves 23 are formed in a straight line along the entire circumferential direction on both sides of the center block 21, and side vertical grooves 24 parallel to the same grooves 23 are formed on the outside of each center vertical groove 23. has been done. The width of the side longitudinal grooves 24 is formed wider than the center longitudinal groove 23, and side lateral grooves 25 that communicate the center longitudinal grooves 23 and the side longitudinal grooves 24 with each other are formed at intervals in the circumferential direction. In this example, the side lateral grooves 25 correspond to and extend outward in the same direction as the center lateral grooves 22,
It has a so-called tapered shape having a portion where the groove width is enlarged in the direction of stretching, and side blocks 26 are formed here.

A shoulder block 27 is formed on the outside of each of the side vertical grooves 24, and is defined by the side vertical groove 24 and the shoulder horizontal groove 28, and a groove 29 is formed at the outside end. , this groove 29 contributes to improving the ground contact of the block during limit running in corners.

In other words, by slightly weakening the rigidity of the block, flexible movement is achieved.

The shoulder lateral groove 28 has a groove portion having the same directionality and angle as the side lateral groove 25 (25°, 45°, 56°, preferably 30° to 35°) and a directionality opposite to this groove portion, and the angle β is 15°. The groove widths of the shoulder lateral grooves 28 are parallel to each other and extend outward.

Further, each of the side block 26 and the shoulder block 27 has a diamond cut portion 26.
A, 27A is formed.

Here, the vertical grooves 23 and 24 and the side horizontal grooves 2
5. Both left and right side blocks 26 and both shoulder blocks 2 separated by shoulder lateral grooves 28
7 is approximately symmetrical left and right with respect to the tread center line O-O, and the phase is shifted in the circumferential direction, and the number of lateral grooves is set to 30 to 50 with respect to the outer circumference of the tire. There is. That is, the tire outer circumference length/number of lateral grooves is set to 30 to 50.

In this case, the intervals between the lateral grooves (circumferential intervals) may be equal, but since this increases tire noise at a certain speed of the vehicle, it is desirable to arrange them at irregular intervals.

A pitch variation method, which is commonly employed, can be used to provide this unequal spacing.

In the first embodiment shown in FIG. 3, the center lateral groove 22 has its starting end on the center center O-O, and in the second embodiment shown in FIG. In the third embodiment shown in FIG. 5, the starting end is located outward from the center line O-O, and in the fourth embodiment shown in FIG. It shows what is happening.

When the tire having the treaded structure of the present invention (tubeless radial tire) is attached to a vehicle, the direction in which the sharp side of the side where the lateral grooves are oriented toward the tire center first enters the road surface is described as forward rotation (normal rotation).
Since the tire has the aforementioned curvature for driving performance, the first contact with the ground is always at the center of the tire tread, with the outer side touching the ground later.

Therefore, when the road surface is wet, it is more rational to drain water outward from the center line of the tire on both sides.

It is important to run on the road surface while cutting the water film, and the flatter the tire, the more horizontally egg-shaped the contact surface, so the flow of water across the entire contact surface is symmetrical. It is important that the

Therefore, in this embodiment, the center block 21 is used to ensure stability at small steering angles, while the center horizontal groove 22 cuts the water film, and the center vertical groove 23 is used to quickly drain the water since it is straight. Therefore, drainage is made good in the central part of the ground, and the drainage direction is directed outward by the side horizontal grooves 25 to join the side vertical grooves 24, and further,
While the side vertical grooves 24 allow linear drainage, the shoulder lateral grooves 28 further improve drainage.

Regarding wear during cornering, if the angle of the shoulder lateral groove 28 is the same as the angle of the other lateral grooves when cornering at the limit, the rigidity of the shoulder block 27 will decrease and wear will increase, resulting in a change in performance. and tire life will be shortened,
Here, when driving in the wet, the larger the angle of the shoulder lateral groove 28 (30° to 35°), the better.By reducing the angle of the part that makes contact with the ground when cornering, the rigidity can be increased here and the groove 29 Together, they provide a good balance of performance.

Further, according to the example shown in FIG. 7 in which the width of the side lateral groove 25 is tapered and enlarged, drainage to the outside in the lateral direction is improved, and the diamond cut portions 26A, 27
Together with A, this will have a synergistic effect on the drainage of the vertical grooves 23 and 24.

In other words, for dry performance, grip power is improved by increasing the block's total ground contact area ratio to 70%, and for wet performance, the best effect is achieved by keeping the total groove area ratio to 30%. It is possible.

(Effects of the Invention) In summary, the present invention improves the drainage performance in the circumferential direction by the circumferentially straight vertical grooves including the center vertical groove and one or more side vertical grooves, and Since the center lateral groove, side lateral groove, and shoulder lateral groove are inclined with respect to the center of the tire, water drainage to the outside in the lateral direction is reasonably ensured, and the center block, side block, and shoulder block are By increasing the ground contact area, grip performance can be ensured on both wet and dry road surfaces.

Furthermore, since a center block is formed on the center of the tire that extends along the entire length in the circumferential direction, the response at small steering angles can be sharpened. Because they are formed out of phase,
In addition to better cutting of the water film, there are advantages such as better noise dispersion because both side blocks and shoulder blocks are arranged in a so-called staggered manner with their phases shifted in the circumferential direction.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a tire having a tread structure according to the present invention, FIG. 2 is an enlarged view of a portion thereof, and FIGS. 3 to 6 are developed plan views showing four embodiments of the present invention. be. 14...Tread portion, 21...Center block, 22...Center lateral groove, 23...Center vertical groove, 24...Side vertical groove, 25...Side lateral groove,
26...Side block, 27...Shoulder block, 28...Shoulder lateral groove.

Claims (1)

[Scope of Claims] 1. A plurality of longitudinal grooves are formed on the outer surface of the tread portion of the tire at intervals in the tread width direction and are continuous along the entire length in the circumferential direction, and a plurality of longitudinal grooves are formed that connect the longitudinal grooves in the tread width direction. The horizontal grooves of the book intersect at an angle with respect to the center of the tread and are arranged at intervals in the circumferential direction of the tire, forming a block defined by each of the longitudinal grooves and the horizontal grooves, and forming a ground contact portion of the block. In a vehicle tire tread structure in which the total area of the tread portion 14 is large and the total area of the longitudinal grooves and the lateral grooves is small, the block is disposed on the center of the tread portion 14 and is formed over the entire circumferential direction. a rib-shaped center block 21, both side blocks 26 formed on the outer side of the center block 21 in the tread width direction through straight vertical grooves 23 in the circumferential direction; It consists of both shoulder blocks 27 formed on the outside through straight vertical grooves 24 in the circumferential direction, and the horizontal grooves 22, 25, 28 are formed on both sides of the center block 21 at an angle with respect to the center of the tread. Left and right center lateral grooves 22 are formed to intersect with each other and are shifted in phase in the circumferential direction, and side lateral grooves are formed to extend substantially linearly from the center lateral grooves 22 to both outer sides in the tread width direction. 2
5 and a shoulder lateral groove 28, and both left and right side blocks 26 and both shoulder blocks 27, which are partitioned by the longitudinal grooves 23, 24, the side lateral grooves 25, and the shoulder lateral groove 28, are substantially symmetrical left and right with respect to the center of the tread and are circular. A tread structure for a vehicle tire characterized by a phase shift in the circumferential direction.