JPH061118A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To reduce pattern noise while holding tractive force constant and improve partial wear resistance by dividing a tread face into an imaginary central area and side areas, and restricting the lateral grooves extending from one end of a tread to the other end. CONSTITUTION:Each block 5 is formed of a lateral groove 3 and a longitudinal groove 4 extending from tread end edges E1 and E2 in a tread face 2, and the tread face 2 is imaginarily divided into a central area M and side areas S by imaginary lines L separated from the tire equator C by a distance of 0.1 to 0.2 times of tread width TW. Lateral grooves 3A whose groove width GW gradually increases from the tread edge E1 toward E2 and lateral grooves 3B whose groove with gradually decreases are arranged with their respective center lines being adjacent and parallel with each other in such a way that they are inclined in the upper right direction at an angle of about 45 deg. to the tire equator C and in the center area M and in the opposite direction in the side areas S, forming an S shape. In addition, the direction in which the width W of the lateral grooves 3A and 3B increase is made opposite. Therefore, pattern noise can be reduced while holding tractive force constant and wear resistance can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention regulates the main groove forming a tread pattern, particularly the lateral groove extending to the tread edge, so that the pattern noise can be reduced while maintaining the traction force and the uneven wear resistance can be improved. Regarding tires.

[0002]

2. Description of the Related Art For example, in a pneumatic tire for an all-terrain vehicle capable of traveling in Muningchi, conventionally, in order to maintain the indexing force in Muningchi, the number of vertical grooves and lateral grooves has been changed. Along with the increase in number, a block pattern in which the groove width and the groove depth are increased has been adopted.

[0003]

However, in the tire having the above-described structure, the cross-sectional area of the groove increases, so that the groove shape between the tread surface and the road surface at the time of running is a tunnel shape of both end openings. Since this air column space is created, this air column resonates and a pattern noise called a so-called air pumping sound that resonates in the vicinity of 100 Hz is generated.

In order to suppress the generation of this pattern noise, conventionally, a method of reducing the sectional area of the groove portion such as groove width and groove depth, a method of shortening the length of the lateral groove, etc. have been adopted.
In the former case, the traction force is reduced, and in the latter case, the drainage property is reduced, so that hydroplaning is likely to occur, and uneven wear is caused to deteriorate the durability of the tire.

The inventor has
As a result of repeated research to reduce pattern noise and prevent uneven wear, by bending the lateral groove connecting the tread edges in a zigzag shape and gradually increasing or decreasing the groove width from one to the other, They found that they could solve the problems and completed the present invention.

According to the present invention, the lateral grooves formed on the tread surface are made to have opposite inclination directions in the central region and the side regions, and the groove width is gradually increased or gradually decreased from one tread edge toward the other tread edge. Based on the above, it is an object of the present invention to provide a pneumatic tire that can reduce pattern noise and enhance wear resistance without reducing traction force.

[0007]

According to the present invention, a block divided on a tread surface by a plurality of lateral grooves extending from one tread edge of the tread to the other tread edge and a vertical groove connecting the lateral grooves. A block pattern pneumatic tire having: a central region between two imaginary lines that separate the tread surface at a distance of 0.1 to 0.2 times the tread width from the tire equator to both sides in the tire axial direction. ,
The lateral groove is virtually divided into two side regions between each imaginary line and the tread edges on both sides, and the lateral groove is inclined in the same direction and at substantially the same angle with respect to the tire equator in each side region, and in the central region. Is inclined in the direction opposite to the side region with respect to the tire equator, gradually increases or decreases its groove width from one tread edge toward the other tread edge, and the lateral grooves adjacent to each other in the tire circumferential direction, The pneumatic tire is characterized in that the increasing directions of the groove widths are opposite to each other.

[0008]

Function: The tread surface is formed by a block pattern. This increases grip and facilitates traveling on soft roads such as mud and sand.

The lateral groove extends from one tread edge of the tread to the other tread edge, and gradually increases or decreases the groove width from the one tread edge to the other tread edge. This prevents the occurrence of a constant cavity in the air column at both ends of the groove formed by the groove between the tread surface and the road surface during tire running, and makes it easier for the air in the air column to escape. Can be prevented from resonating, and the generation of pattern noise can be effectively prevented.

Further, the tread surface is provided with two imaginary lines at positions separated by 0.1 to 0.2 times the tread width from the tire equator on both sides, and a central region between the imaginary lines,
It is virtually divided into an imaginary line and a side area between the tread edges.
Therefore, the tire is in a normal state where a normal internal pressure and a normal load are applied, so that the central area and the two side areas on both sides thereof come into contact with each other.

On the other hand, the lateral groove has different inclination directions in the side region and the central region, and therefore, the lateral groove is bent at two places on the ground contact surface. As a result, it is possible to prevent the pattern from having directivity, prevent the flow of the vehicle at the time of traveling, and easily secure an effective edge component for holding the traction force in the central region.

In addition, the lateral grooves adjacent to each other in the tire circumferential direction are
Since the direction of increasing the groove width is opposite to each other, the area of each block can be equalized, so that the Landsee ratio, which is the ratio of the total area of the groove surface in the side region to the total area of the peripheral surface of the block, is equal. Can be easily realized, and thus uneven wear can be prevented from occurring.

As described above, the pneumatic tire of the present invention is
By organically combining and integrating the above-mentioned components, it is possible to suppress the generation of pattern noise and enhance wear resistance while maintaining the traction force.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings by taking as an example the case where a pneumatic tire 1 is a tire for an all-wheel drive vehicle that travels on a soft road such as a mud terrain.

1 and 2, the pneumatic tire 1 connects a plurality of lateral grooves 3 extending from one tread edge E1 of the tread to the other tread edge E2 of the tread on the tread surface 2 to the lateral grooves 3. A block pattern having blocks 5 separated by the vertical grooves 4 is formed.

The pneumatic tire 1 has the tread surface 2
An outer peripheral surface of the tread portion 12, a sidewall portion 13 extending from both ends thereof inward in the tire radial direction, and a bead portion 14 located at an inner end of the sidewall portion 13 in the tire radial direction. In the filled tire 1, a carcass 16 is formed by folding the bead core 15 of the bead portion 14 from the tread portion 12 through the sidewall portion 13 toward the outer side in the tire axial direction, and inside the tread portion 12 and in the radial direction of the carcass 16. Belt layer 1 arranged on the outside
7 and.

The carcass 16 comprises one or more carcass cords in this embodiment, which are carcass cords of radial arrangement or semi-radial arrangement inclined at an angle of 70 to 90 ° with respect to the tire equator C, and in the present embodiment, one or more. It is made of carcass ply, and as the carcass cord, an organic fiber cord such as nylon or polyester aromatic polyamide is used.

The belt layer 17 is, in this embodiment, a first belt ply 17 disposed adjacent to the carcass 16.
A and a second belt ply 7B arranged outside the first belt ply 17A. In this example, the first and second belt plies 17A and 17B are made of nylon, polyester or aromatic polyamide. Belt cords made of such organic fibers or steel cords are arranged side by side with respect to the tire equator C.

On the tread surface 2, a distance of 0.1 to 0.2 times the tread width TW, which is the distance between the one and the other tread edges E1 and E2 in the tire axial direction, from the tire equator C in the tire axial direction. Two imaginary lines L, L which are respectively separated on both sides and circulate in parallel to the tire equator C are set, and the tread surface 2 is provided with a central region M between the two imaginary lines and each imaginary line L, L and both sides. It is virtually divided into two side regions S, S between the tread edges E1, E2.

As a result, when the tire is mounted on the standard rim J and a regular internal pressure and a regular load are applied, the ground contact surface F is divided into the central region M and the two side regions S and S located on both sides thereof. It has a substantially equal area and straddles. The position of the virtual line L from the tire equator C is the tread width TW.
If it is less than 0.1 times, the width of the side area S becomes larger than that of the central area M, and conversely if it exceeds 0.2 times, the central area M
Is larger than the width of the side region S.

The lateral groove 3 has an S-shape, and in the two side regions S, S, the lateral groove 3 rises to the left in FIG. 1, and in this embodiment, is approximately 45 ° with respect to the tire equator C.
Is formed with a gentle arc shape. In the central area M, the lateral groove 3 is inclined to the right in FIG. 1, and is therefore inclined at an inclination in the opposite direction to the side area S, and in this embodiment, it is approximately 45 ° with respect to the tire equator C. Is inclined at an angle of.

In the present embodiment, the vertical groove 4 intersects with a central vertical groove 4A that circulates on the tire equator C, and a plurality of lateral grooves 3 ... Between the central vertical groove 4A and the tread edges E1 and E2. Also, the vertical grooves 4B on the side arranged in a direction intersecting with the tire equator C, and the vertical groove 4C for a small length joint arranged between the vertical grooves 4B on the side, 4B.

The tread surface 2 is formed with a block pattern consisting of these lateral grooves 3, ..., Vertical grooves 4, ... And a plurality of blocks 5 surrounded by the tread edges E1, E2.

Further, the lateral groove 3 has a first lateral groove 3A whose groove width GW gradually increases from one tread edge E1 toward the other tread edge E2, and from one tread edge E1 to the other tread edge E2. The second lateral groove 3B whose groove width GW gradually decreases, and the first and second lateral grooves 3A and 3B.
Are arranged such that their groove center lines are parallel and adjacent to each other in the circumferential direction.

The groove width GW is in the range of 0.015 to 0.02 times the tread width TW in the narrow width portion GW1 and 0.0 of the tread width TW in the wide width portion GW2.
It is preferably in the range of 5 times to 0.08 times. In this way, by gradually increasing or decreasing the groove width GW, it is possible to prevent a stationary cavity from being generated in the lateral groove 3 and to facilitate the escape of the air passing through the lateral groove 3, thereby preventing the resonance of the air in the groove. Yes, it effectively prevents the generation of pattern noise.

Further, the vertical groove 4B on the side is also gradually reduced toward the tread edge side of the groove width similarly to the lateral groove 3, and like the lateral groove 3, the pattern noise is reduced.

The lateral grooves 3, 3 adjacent to each other in the tire circumferential direction
As described above, the directions in which the groove width W increases are made opposite to each other, so that the circumferential length 1 of the blocks 5 becomes uniform over substantially the entire area in the tire axial direction, and the rigidity of the blocks is made uniform. Planned. As a result, uneven wear can be prevented, and the noise caused by the grounding wear noise caused by the grounding of the blocks 5 can be reduced.

The lateral groove 3 preferably has a groove depth GH in the range of 0.06 to 0.16 times the tread width. Furthermore, blocks 5 in the entire area of the tread surface 2 ...
50:50 to 75: the Landsee ratio, which is the ratio of the total area of the peripheral surface of the above to the total area of the groove portions formed by the lateral grooves 3 and the vertical grooves 4.
The range of 25 is more effective for reducing pattern noise.

[0029]

[Specific example] Tire size is 31 × 10.50R15 6.
A tire (Example) having PR and a tread pattern shown in FIG. 1 and a configuration shown in FIG. 2 was prototyped and its performance was tested. For comparison, the tires having the conventional structure shown in FIGS. 3 and 4 (Comparative Examples 1 and 2) were also tested and their performances were compared. In Comparative Examples 1 and 2, the lateral groove g is inclined in substantially the same direction with respect to the tire equator c, and the groove width w is also formed to have substantially the same dimension.

The test method was as follows. During the test, an internal pressure of 2.0 kg / cm ² was applied to the test tire. A) Pattern noise The overall noise was measured by rolling a test tire on a drum by a noise measuring method defined by JASO, and the result was expressed as an inverse index with Comparative Example 1 being 100. The larger the value, the smaller the noise.

(B) Mud traction performance The maximum traction force to be pulled from a stationary state in the Muning area with test tires mounted on all wheels of the test vehicle was 10
It is indicated by an index of 0. The larger the value, the higher the traction force.

C) Uneven wear (heel and toe wear) A test tire was subjected to a load of 500 kg and a slip angle of 0 to 1 degree on a test bench, and the tire was run at a speed of 80 kg / H for 24 hours. After that, the difference in the amount of wear at the circumferential edge of the block located near the tread edge was measured, and the result was expressed as an inverse index with Comparative Example 1 being 100. The larger the value, the better. The test results are shown in Table 1.

[0033]

[Table 1]

Test Results Comparative Examples 1, 2
It was confirmed that the pattern noise can be reduced and the wear resistance can be improved while maintaining the traction force as compared with the above-mentioned one.

[0035]

As described above, the pneumatic tire of the present invention is
The lateral groove is formed as a zigzag groove in which the directions of inclination in the central region and side regions of the tread are opposite directions, and the groove width of the lateral groove is gradually increased or gradually decreased from one tread edge toward the other tread edge, and the adjacent As the gist of the matching lateral groove is to increase the width of the groove in opposite directions,
Pattern noise can be reduced while maintaining traction, and wear resistance can be improved. The tire having the above-described configuration of the present application is not limited to the tire for all-wheel drive vehicles that travel in the Muning area, and may be a tire for traveling on general roads.

[Brief description of drawings]

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

FIG. 2 is a sectional view of the tire in the meridional plane direction.

FIG. 3 is a developed plan view showing a tread pattern of a conventional tire.

FIG. 4 is a developed plan view showing a tread pattern of a conventional tire.

[Explanation of symbols]

 2 Tread surface 3, 3A, 3B Horizontal groove 4 Vertical groove 5 Block C Tire equator E1, E2 Tread edge GW Groove width L Virtual line M Central area S side area TW Tread width

Claims (1)

[Claims] 1. A pneumatic tire of a block pattern having a block on a tread surface, the block being divided by a plurality of lateral grooves extending from one tread edge of the tread to the other tread edge and a vertical groove connecting the lateral grooves. The tread surface is a central region between two imaginary lines that separate the tread width by 0.1 to 0.2 times the tread width from the tire equator to both sides in the tire axial direction. The lateral groove is virtually divided into two side regions between the edge and the lateral groove, which is inclined in the same direction and at substantially the same angle with respect to the tire equator in each side region, and with respect to the tire equator in the central region. While slanting in the opposite direction to the side region, the groove width is gradually increased or decreased from one tread edge toward the other tread edge, and the lateral grooves adjacent in the tire circumferential direction are A pneumatic tire characterized by the direction of increasing the width and opposite to each other.