JPH04358907A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To reduce noise from a tire. CONSTITUTION:Hollow parts 2 which do not continue with each other are formed on a tread ground contact part 1 with clearance in a circumferential and width directions, the outline shape of the respective hollow parts 2 is formed so that the front side in a tire rotational direction may be narrower and the width may gradually become larger toward the rear side, and the crossing angle between hollow part central lines Y-Y which cross a tire equator X-X on the more frontal side in the rotational direction of the tire from the respective hollow parts 2, and the tire equator is made larger toward the farther part from the tire equator.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire suitable for use in passenger cars, and particularly to a pneumatic tire that advantageously reduces noise generated from the tire.

0002

2. Description of the Related Art Conventionally known pneumatic tires for passenger cars include, for example, as shown in FIG. There is one in which a plurality of widthwise grooves 12 extending in the widthwise direction of the tire are formed in the tread surface.

0003

[Problems to be Solved by the Invention] However, in such conventional tires, each circumferential groove 11 extends continuously not only within the ground contact area but also outside the ground contact area. The same applies to the directional grooves, so
their respective grooves forming air column tubes within the grounding area 1
Air column resonance occurs in the tires 1 and 12, and the generated resonance noise is dissipated to the outside of the ground contact area through the mutually continuous grooves 11 and 12. This causes an increase in the noise level of the noise generated from the tires. There was a problem with the cause.

The present invention advantageously solves the problems of the prior art, and provides a pneumatic tire that can effectively reduce the noise generated by the tire by preventing the occurrence of air columnar resonance itself. It provides:

[0005]

[Means for Solving the Problems] The pneumatic tire of the present invention has a center line in the tread surface portion that is sufficiently shorter than the respective lengths of the tread contact area in the circumferential direction and the width direction, and that is not continuous with each other. A plurality of recesses are formed at intervals in the circumferential direction and width direction, and the outline shape of each of the recesses is such that the front width in the rotational direction of the tire is narrow and the width gradually becomes wider toward the rear side. At the same time, the angle of intersection between the center line of the recess and the tire equator line, which intersects with the tire equator line on the front side of each recess in the rotational direction of the tire, is made larger as the recess is farther away from the tire equator.

[0006]

[Function] In this pneumatic tire, each recess has dimensions sufficiently smaller than the length of the tread contact area in each direction in both the tire circumferential direction and the width direction. , since the depressions are discontinuous with each other, there is no risk that each depression will form an air column within the tread contact area;
The occurrence of air columnar resonance can be reliably prevented. Therefore, resonance noise is not dissipated outside the ground area.

[0007] Furthermore, each recessed portion of this tire has a contour shape that is narrow at the front side in the rotational direction of the tire and gradually becomes wider toward the rear side, and the recessed portion is located away from the tire equator line. As the angle of intersection between the center line of the depression and the tire equator line increases, the water in the contact area can be pushed out smoothly to the front and to the sides, and as a result, This effectively prevents the occurrence of hydroplaning.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. FIG. 1 shows a tread pattern showing an embodiment of the invention. Note that the internal reinforcement structure of the tire is the same as that of a conventional general radial tire, so illustration thereof is omitted here. As shown in the figure, a plurality of recesses 2 that are not continuous with each other are formed in the tread surface 1 at intervals in the circumferential direction and the width direction of the tire,
The contour shape of each of these recessed portions 2 is made into a trapezoidal shape that gradually becomes wider toward the rear side in the rotational direction of the tire. Note that the contour shape of the recessed portion 2 does not necessarily have to be a trapezoidal shape, and may have a shape in which at least one of the legs and the bottom of the trapezoid is curved outward or inward.

[0009] Here, except for the recess 2 located on the tire equator line XX, each recess 2 is defined along its center line Y-X.
Y is tilted in a direction that intersects the tire equatorial plane XX on the front side in the rotational direction of the tire from the recess 2, and the intersection angle between the recess center line Y-Y and the tire equatorial line XX is set to the tire equator line. The recessed portion 2 farther from XX is made larger.

Incidentally, in this example, the tread surface width is set to 1.
50mm, the ratio of the land area within the contact area is approximately 62%, and the depth of each recess 2 is 8mm, and the intersection angle between the recess center line Y-Y and the tire equator line X-X is determined by the tire As you move away from the equator line XX, from 5° to 30°,
It is increased at 5° intervals. Also, the negative rate is 50
% or less, in this example about 38%.

According to the tire constructed as described above, since each recess 2 has sufficiently small dimensions as described above, the occurrence of the air column resonance phenomenon can be reliably prevented.
The noise generated by the tires can be significantly reduced.

On the other hand, the recesses 2 can provide excellent wet drainage, as described above, based on their own contours and their respective positions. [Comparative Example] A comparative test will be described below regarding the noise data in the vehicle interior and the rate of occurrence of the hydroplaning phenomenon between the invention tire shown in FIG. 1 and the conventional tire shown in FIG. 2 in actual driving. ◎Invention tire having the tread pattern shown in Figure 1, size 225
/50ZR16 tires were mounted on 16 x 8J rims and an actual vehicle was driven. The load capacity of the vehicle is 360kg.
It was set as f. ◎ Conventional Tire A tire of the same size as the invention tire and having the tread pattern shown in Figure 2 was mounted on a rim of the same size as the invention tire, and the tire was driven on an actual vehicle. The live load in this case was also 360 kgf. ◎Test Results The results of the comparative test are shown in Table 1. According to this table, the invented tire hardly reduces the speed at which the hydroplaning phenomenon occurs.
It is clear that cabin noise can be effectively reduced compared to conventional tires.

[0013]

According to the present invention, the noise generated by the tire can be effectively reduced while ensuring sufficient resistance to hydroplaning.

[Brief explanation of drawings]

FIG. 1 is a tread pattern showing an embodiment of the invention.

FIG. 2 is a tread pattern showing a conventional example.

[Explanation of symbols]

1 Tread surface 2 Recessed part X-X Tire equator line Y-Y Center line of depression

Claims (1)

[Claims] 1. Forming recesses that are not continuous with each other in the tread surface at intervals in the circumferential direction and the width direction,
The contour shape of each depression is such that the front width in the tire rotation direction is narrow and gradually widens toward the rear, and the depression intersects with the tire equator line at the front side of the tire rotation direction from each depression. A pneumatic tire in which the angle of intersection between the center line of the tire and the tire's equator line becomes larger as the recess is farther away from the tire's equator line.