JPH0550811A - Pneumatic radial tire - Google Patents

Abstract

PURPOSE:To reduce tire pattern noise by equalizing mutually and substantially the tire circumferential total lengths of various circumferential pitches at least one land row portion. CONSTITUTION:This tire is equipped with plural land portion rows, and land portion elements at respective land portion rows have circumferential pitches of plural kinds. Hereupon, at least at one land portion row, the tire circumferential total lengths of various circumferential pitches are equalized mutually and substantially. As a result, as the harmony of pitch arrangements is realized and noise peaks are effectively dispersed, pattern noise can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic radial tire having a plurality of land rows and, more particularly, to an effective reduction of pattern noise.

[0002]

2. Description of the Related Art It has been widely and generally practiced to reduce pattern noise by a so-called variable pitch in which a plurality of land elements in the land row have two or more kinds of circumferential pitches. There was no specific provision as to what proportion and order of the various circumferential pitches should be placed on the tire circumference.

[0003]

Therefore, depending on the pitch arrangement, noise generated by rolling of the tire has a large peak in a specific frequency band, which is a major cause of worsening pattern noise. Was there.

The present invention has been made in view of such problems of the prior art, and provides a pneumatic radial tire capable of advantageously reducing pattern noise by suppressing the peak value of generated noise to be low. To do.

[0005]

The present invention has been made as a result of performing various simulations with respect to respective arrangement ratios of a plurality of kinds of circumferential pitches, and a pneumatic radial tire according to the present invention has a plurality of In a tire having a land row of books, in which the land elements of each land row have two or more kinds of circumferential pitches, the total of the various circumferential pitches in the tire circumferential direction is within at least one land row. The lengths are substantially equal to each other.

[0006]

According to the result of the simulation, it has been confirmed that such a pneumatic radial tire can suppress the peak value of noise to a sufficiently low level.

This is based on the result that the peak lengths of noise are effectively dispersed by harmonizing the pitch arrangement by making the total lengths in the tire circumferential direction of various circumferential pitches substantially equal to each other. It is a thing.

[0008]

Embodiments of the present invention will be described below. In the case where the tire size is 165 R14, here, in arranging three types of circumferential pitches in a three-mountain arrangement, there are a first circumferential pitch, a second circumferential pitch, and a third circumferential pitch. The pitch ratio is 9:10:11, and the number of each of them arranged on the circumference is 24
The second circumferential pitch is 22, and the third circumferential pitch is
By setting the total number of pitches on the circumference to be 65, the occupation ratios of the respective pitches on the tire circumference are made substantially equal to each other.

Here, the length of each circumferential pitch in the tire circumferential direction is, for example, 27.24 mm at the first circumferential pitch,
30.27 mm at the second circumferential pitch, at the third circumferential pitch
It can be 33.29 mm, and the specific arrangement mode of each of these pitches on the tire circumference can also be set as follows, for example. 1st mountain 11112 22233 33333 2222 2nd mountain 1 11111 11222 23333 33322 2 3rd mountain 1111 11111 11123 33332 222222 1 --- first circumferential pitch 2 --- second circumferential pitch 3 --- third Circumferential pitch

When the pitches are arranged in this way,
The total length of the first circumferential pitch in the tire circumferential direction,
Each of the second circumferential pitch and the similar lengths of the third circumferential pitch will be substantially equal to each other and each pitch will account for 1/3 of the tire circumferential length. Figure 1
Is a graph showing the frequency characteristics of pattern noise under such a pitch arrangement, according to which the maximum amplitude was 18.0 and the maximum sound pressure at this time was 28.2 dB.

On the other hand, the pitch ratio of the first, second, and third circumferential pitches is 9:
In addition to 10:11, the total number of pitches on the circumference is set to 65 in the same manner as described above, and the number of pitches arranged on the circumference is set to both the first and second circumferential pitches. 22 and the third circumferential pitch is 21, the comparative tire I in which the number of arrangements of each pitch is substantially equal, and the respective number of arrangements on the circumference are A comparative tire II in which both the circumferential pitches are 16 and the second circumferential pitch is 33 so that the arrangement ratio of the first, second and third circumferential pitches is substantially 1: 2: 1. When the frequency characteristics of the pattern noise were measured for each of the above, the results were as shown in FIG. 2 and FIG. 3, respectively.

By the way, the concrete pitch arrangement of the comparative tire I is as follows: the first mountain 11111 11222 22233 3333322 the second mountain 111 11112 23333 33333 32222 the third mountain 11111 11122 23333 22222, and the specific pitch of the comparative tire II. The arrangement mode was 1st mountain 11122 22223 33333 32222 2 2nd mountain 1111 11222 22233 33222 3rd mountain 11111 11222 22222 3333322222. Here, according to the graphs shown in FIGS.
The maximum amplitude is 19.1 for comparative tire I and for comparative tire II.
There was S at 19.6, and the maximum sound pressure of each was 28.9 dB for comparative tire I and 29.3 dB for comparative tire II.

According to these respective figures, the invention tire shows a value smaller than the comparison tires I and II by 1.0 or more in terms of the maximum amplitude, and also in terms of the maximum sound pressure.
It will show a value smaller than 0.7 dB. As is apparent from these, according to the present invention, by making the total lengths in the tire circumferential direction of the various circumferential pitches substantially equal to each other, the tire circumferentials of various circumferential pitches can be obtained. When the total pitches in the respective directions are made equal to each other, and the total arrangement ratio in the tire circumferential direction of the various circumferential pitches is 1: 2: 1 for each of the first, second and third circumferential pitches. The maximum amplitude and the maximum sound pressure can be reduced sufficiently effectively as compared with any of the above cases.

[0014]

As described above, according to the present invention, the pattern noise can be effectively reduced with little or no influence on other performances of the tire.

[Brief description of drawings]

FIG. 1 is a graph showing frequency characteristics of a tire according to the invention.

FIG. 2 is a graph showing frequency characteristics of comparative tire I.

FIG. 3 is a graph showing frequency characteristics of comparative tire II.

Claims (1)

[Claims] 1. A tire comprising a plurality of land rows, the land elements of each land row having a plurality of circumferential pitches, wherein at least one land row has various circumferential pitches. , A pneumatic radial tire in which the total length in the tire circumferential direction is substantially equal to each other.