JPS63279902A - Low noise tyre - Google Patents

Abstract

PURPOSE:To reduce the generation of pattern noise by a method wherein, in a radial tyre for an automobile having a plurality of pitch array rows, phase deviation is provided for a repetition pattern between pitch arrays, and a relation between the phase deviation and the length of a repetition pattern and a distance between the pitch arrays is specified. CONSTITUTION:In a tread pattern, blocks 3 are arranged circumferentially at a specified period by means of main grooves 1 and auxiliary grooves 2 to form pitch arrays 4a-4c. A distance between centers of the pitch arrays, for example, a distance LO between central lines 6a and 6b of the pitch arrays 4a and 4b, a phase difference A of the repetition pattern of the pitch array, and a length LO of a repetition pattern in each pitch array are set so as to satisfy a relation formula of 6LP.LO<A<12LP.LO. This constitution forces propagation of vibration generated when the blocks of the pitch array are earthed or separated from a road surface to interfere with vibration generated from the adjoining pitch array for offset. Thus, the generation of pattern noise can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a radial tire with low batash noise.

(Conventional technology and its problems) The so-called "battery noise" that is generated by the contact between tires and the road surface when a car is running is caused by the discontinuity of the tire's contact surface due to the presence of tread bumps, and the vibration-exciting force in the contact area. This is thought to be mainly caused by the vibration noise generated when the side parts of the tire are vibrated.

Batashi noise changes depending on the shape of the tire's tread pattern, but especially for tires with a tread pattern that has a pitch arrangement consisting of a repeating pattern in the circumferential direction.
As a result of the repetitive pattern periodically touching and leaving the ground, the tire is excited to vibrate at a constant frequency depending on the driving speed, producing large patter noise.

Various attempts have been made to reduce these perturbation noises, but no effective method for reducing perturbation noise has been found.

[Means for solving problems]

As a result of repeated research to solve the above problems, the inventors of the present invention found that in a tire with a tread pattern that has multiple pitch arrays, the vibrations generated by each pitch array are equal to the distance from each pitch array to the side of the tire. The time required for vibration transmission differs depending on the pitch arrangement, and by interfering with each other to cancel each other out, the vibration waves emitted from each pitch arrangement and reaching the tire side part are suppressed. The inventors have discovered a scale that can reduce batash noise and have completed the present invention.

That is, the present invention provides a pneumatic tire having a radial structure with a tre-sido pattern having a pitch array consisting of at least three rows of continuous repeating patterns in the circumferential direction. There is a phase shift between the repeating patterns of the pitch array, and the phase shift A is such that the pitch array on the ground-contacting end side is positioned more rearward in the tire traveling direction than the pitch array on the adjacent center line side in the direction of the tire center, and the pitch array is When the length is Lp and the distance between the centers of adjacent pitch arrays is LO, 5 Lp-Lo (A (12Lp-L).

The gist of the present invention is to provide a low-noise tire characterized by having at least one pair of pitch arrangement combinations as follows.

Next, the contents of the present invention will be explained in detail with reference to the drawings. Fig. 1 is a developed view of an example of the tire winding pattern of the present invention. In the tread pattern shown in Figure 1, the pitch arrangement is such that the blocks (3) surrounded by the circumferentially continuous main grooves (1) and the minor grooves (2) that connect the main grooves are arranged at almost constant intervals in the circumferential direction. (4), and only the right half of its Toshi-Sodobatashi center line II is shown. In this pattern, the center line (6a) of the grounding part of the 0 pitch arrangement (4a) is focused on the pitch arrangement (4a) closest to the grounding end (5) and the pitch arrangement (4b) adjacent to this. ) and the center line (6b) of the pitch array (4b) is Lo(Q), and the distance between the center line (6b) of the pitch array (4B) and the pitch array (4b) is
The phase difference between (6a) and (6a) is A H1. The length of the repeating pattern of each pitch arrangement (4a) and (4b), that is, the pitch length is LP(77+). At this time 5 Lp-L
o (A (12Lp-L.

,・　.

In a tire with the tread pattern shown in Figure 1, the center line I-
Assuming that the pitch array (4C) adjacent to I and the pitch array (4b) adjacent to it are constant, 'pitch array (4a)
Type p+ in which only the phase difference A between pitch array (4b) and pitch array (4b) is changed.
We produced various prototype tires of T size 195/60R14 and 165/801412, and approved them by the Automotive Technology Association and the Automobile Standards (J
ASO) C606 tire unit bench test method: 20~
Within the speed range of 100 kml k, the Batashi noise was measured by changing the speed by 5 kml h, and the average value of the noise level (0, A, L,) at that speed was determined, and the phase A was 0. The difference from the average noise level at each phase A (level at A~0 - level at A=0) 7&- was calculated using that at the time as a reference. The results are plotted on the horizontal axis and A1, and the noise level difference is plotted on the vertical axis.

When , the absolute value of the noise level difference increases rapidly in the negative direction. That is, the noise level becomes smaller.

Therefore 5 Lp-Lo (A (12Lp-L.

By providing the phase difference A in the range of , it is possible to reduce batash noise.

In the tire of the present invention, it is desirable to provide the above-mentioned phase difference between adjacent pitch arrays, but the phase difference may be provided only in a part of the pitch arrays. Since the pitch arrangement closest to the grounding end of each pitch arrangement has the largest contribution as an excitation source for noise generation, at least the above phase difference is provided between this pitch arrangement and the adjacent pitch arrangement. This is desirable.

The pitch Lp within each pitch array does not necessarily have to be constant and may vary by 15 to 20%, but the average pitch Lp of adjacent pitch arrays with a phase difference is almost the same. It is necessary that

(Function) According to the low-noise tire of the present invention, first, when the blocks in the pitch arrangement on the side closer to the center of the tread, which is farther from the ground contact edge, touch the ground or leave the road surface, vibrations are generated;
The vibrations propagate outward in the width direction of the tread and further to the tire side portions due to the inherent vibration transmission speed within the tire.

These vibration waves interfere with the vibrations generated when the adjacent pitch-arranged blocks touch the ground or leave the road surface, and the peaks and troughs of the vibrations cancel each other out, resulting in a reduction in vibration as a whole.

In Figure 1, the outer pitch array (6a) has a phase difference greater than that of the inner pitch array (6b) by an amount corresponding to the time it takes for the vibration from the inner pitch array to be transmitted to the position of the outer pitch array. 5 Lp-Lo ~ 12 Since the tires are shifted backward by Lp-LO with respect to the tire traveling direction, that is, are provided with a delay, the vibration waves from the inner pitch array and the vibration waves from the outer pitch array are exactly the same. The peaks and troughs overlap and interfere and cancel each other out, reducing vibration. As a result, tire pattern noise is reduced.

(Effects of the Invention) According to the low-noise tire of the present invention, by providing a certain phase difference between the pi-sochi arrays that are in contact with each other, vibration waves can be interfered with, and pattern noise can be significantly reduced.

[Brief explanation of drawings]

FIG. 1 is a developed view of the tread pattern of the low-noise tire of the present invention, and FIG. 2 is a graph showing changes in pattern noise when the phase difference between adjacent pitch arrays of the tread pattern is changed. +1+...Main groove (2)...Minor groove (3)
...P0. Tsuku (4)...Pitch arrangement (5
)...Grounding end (6a), (6b)...
Center line patent applicant Yoshi Koyama, patent attorney representing Toyo JM Industries Co., Ltd. 2 Figure 2
1)1 Figure 4

Claims (2)

[Claims] (1) In a pneumatic tire having a radial structure and having a tread pattern having a pitch array consisting of at least three rows of repeating patterns continuous in the same direction, the pitches of each pitch array are approximately equal and the pitch arrays are adjacent to each other. There is a phase shift A (m) between the repeating patterns, A is the pitch length Lp, and the distance between the centers of adjacent pitch arrays is Lo.
When expressed as (m), the pitch arrangement on the ground contact end side is set rearward in the tire traveling direction than the pitch arrangement on the adjacent tire circumferential center line side, and the pitch arrangement is such that 6Lp・Lo<A<12Lp・Lo. A low-noise tire characterized by having at least one pair of combinations of. (2) The low-noise tire according to claim 1, wherein the combination of pitch arrangements is a combination of a pitch arrangement in contact with the ground contact end and a pitch arrangement adjacent thereto.