KR20000037756A - Pitch arranging structure to reduce noise of tires - Google Patents

Abstract

PURPOSE: A structure for arranging pitches is provided to eliminate the influence to pitch noise from a mold division region after molding a tire. CONSTITUTION: A mold division region is partitioned at the boundary line of each pitch. A pitch group is arranged by using each segment of a mold as a single pitch depending upon the length of the mold division region. That is, the pitches are arranged on the entire circumference to reduce noise at the maximum. In the pitch arrangement of an A2 type, the boundary of the mold division region is located on the boundary line of the pitch to reduce t maximum amplitude twice. Therefore, traces of the mold division region are eliminated after molding tires.

Description

Pitch Array for Tire Noise Reduction

The present invention is to reduce the noise of the tire in consideration of the mold partition area that can be applied when there is no step for the pattern of the upper and lower molds in order to minimize the pitch noise of the tire generated by the mold partition area In particular, the structure of the pitch arrangement for the present invention relates to a structure of a pitch arrangement, in particular, instead of dividing the conventional mold division region within the boundary of each pitch, by dividing at the boundary of each pitch, ultimately in the mold region remaining after the tire is molded. The present invention relates to a structure of a pitch array for noise reduction of a tire capable of removing traces and a method of obtaining the same.

As is known, grooves are formed between the blocks of the tread which form the ground plane of the tire and the blocks, and the width of the grooves is called a block pitch, and noise generated between the block pitches Pattern noise, which is the loudest noise generated from tires while driving, is generated.

A typical pitch array structure used for a tread of a conventional tire is set to the largest pitch (L), the intermediate pitch (M), and the smallest pitch (S) so that pitches formed in different rows are arranged along the circumferential direction of the tire. . For example, in the pitch arrangement and pattern shape of the P225 / 50R15 H409 produced by the applicant, there is no step between the top and bottom of the pattern and the pitch arrangement when the pattern is designed within one pitch is LMSSMSSLMLMSSSMLLLMSMSLMSSMLL SSLSSLLSLMSSLLLLSLSLLLLLSLSLSSSSLL, which is shown in FIG. The results of the pitch noise computer simulations on the pitch array are shown graphically.

However, in the related art, since the part of the mold divided region is divided within each boundary of the pitch, the trace of the divided region remains after the tire is molded, and thus there is a problem in that the pattern noise occurs in the tire while driving the vehicle.

Accordingly, the present invention has been made in view of the above problems, and has a tread composed of a plurality of basic pitches around the circumference of the tire, and in the pitch arrangement structure having these pitches of at least three different sized pitches, It is to provide a pitch arrangement structure for reducing the noise of the tire to divide the mold partition area on the boundary of the pitch to remove the effect on the pitch noise caused by the trace of the mold partition area remaining after the tire is molded. Has its purpose.

1 is a noise simulation experiment for an A-type pitch group array formed by a mold partition region.

Is a graph of the results,

2 is a noise simulation result for the A2 type pitch array considering the mold partition region.

graph,

Figure 3 is a graph of the noise simulation results for the conventional pitch array.

According to the present invention for achieving the above object, the mold partition region is divided at the boundary line of each pitch and each pitch group according to the length, that is, each segment (Segment) of the mold is assumed to be one pitch to noise An advantageous pitch group array is obtained, and an optimum low noise pitch array is obtained by applying the pitch array considering the pitch group array on the entire circumference with respect to the original pitch length.

Hereinafter, the present invention will be described in detail with reference to the illustrated tables and accompanying drawings.

As mentioned above, the pitch arrangement of the P225 / 50R15 H409 produced by the applicant is LMSSMSSLMLMSSSMLLLMSMSLMSSMSSLSSLLSLMSSLLLLSLSLLLLLSLSSSSLL, where the largest pitch (L) is 38.7 mm and the median pitch (M) is 27.3 mm and the smallest pitch (S) is 24.7. mm. In addition, the number of mold divided regions is preferably 8 to 10 according to the empirical value considering the roundness of the mold and the manufacturing process. In the present invention, the mold divided regions are all eight as shown in Table 1 below. Pitch group.

Arrangement LMSSMSSL MLMSSSML LLMSMSLM SSMLLSSL SSLLSLMS SLLLLSL SLLLLLS LSSSSLL Pitch group 5 4 One 3 3 2 2 6 Length (mm) 230.8 233.4 247.4 242.2 242.2 242.9 242.9 214.9

In Table 1, the pitch groups according to the length of the mold section were LLMSMSLM of 247.4 mm for the first pitch group, SLLLLSL and SLLLLLS for 242.9 mm for the second pitch group, and 242.2 mm for the third pitch group, respectively. (SSMLLSSL) and (SSLLSLMS), the fourth pitch group (MLMSSSML) of 233.4 mm, the fifth pitch group of 230.8 mm (LMSSMSSL), the sixth pitch group can be seen that (LSSSSLL) of 214.9 mm.

On the other hand, the constraint for each length of the mold partition region is that the difference between the maximum length and the minimum length should be within 10 degrees on the circumference, as

(SL _max -SL _min ) ≤ {∑ (PL (i) × N (i))} × (10˚ / 360˚) ... (1)

Where SL _max is the maximum length of the mold partition, SL _min is the minimum length of the mold partition, PL (i) is the length of each pitch, and N (i) is the number of pitches for the length of each pitch, For example, the maximum length of the mold partition in Table 1 is 247.4 mm in the first pitch group and the minimum length is 214.9 mm in the sixth pitch group, so the difference is 32.5 mm, which is 6.16 ° on the circumference, so Satisfied.

In addition, as a constraint for each length of the mold segment, the following empirical formula limits the tolerance on the circumference,

{∑ (PL (i) × N (i))}-π × D≤0.5 mm

Where PL (i) is the length of each pitch, N (i) is the number of pitches for the length of each pitch, and D is the overall diameter of the mold.

Next, when the computer simulation is performed on the pitch noise with each length of the mold division as one pitch group, the results shown in Table 2 are obtained.

division Pitch Group Amplitude Dispersion sampling Relative ranking A 12345632 12.35 Good 56.27% One B 14253623 13.06 Good 54.67% 2 C 16352423 13.36 Good 54.70% 3 D 16234523 13.87 Good 54.63% 4

As shown in Table 2, it can be seen that the maximum amplitude level of the A-type pitch group array, that is, (12345632) array is 12.35, so that this pitch group array is the most advantageous for the noise, and the pitch noise for the A-type pitch group array is The results of the computer simulations are shown graphically in FIG. 1.

However, as shown in Table 1, since there are two pitch arrays in the second pitch group and the third pitch group, respectively, when each pitch group array is arranged on the actual circumference, each pitch group array is as shown in Table 3 below. There are two pitch arrays each.

Pitch Group division Pitch array 54133226 Conventional LMSSMSSLMLMSSSMLLLMSMSLMSSMLLSSLSSLLSLMSSLLLLSLSLLLLLSLSSSSLL 12345632 A1 LLMSMSLMSLLLLSLSSMLLSSLMLMSSSMLLMSSMSSLLSSSSLLSSLLSLMSSLLLLLS A2 LLMSMSLMSLLLLLSSSLLSLMSMLMSSSMLLMSSMSSLLSSSSLLSSMLLSSLSLLLLSL 14253623 B1 LLMSMSLMMLMSSSMLSLLLLSLLMSSMSSLSSMLLSSLLSSSSLLSLLLLLSSSLLSLMS B2 LLMSMSLMMLMSSSMLSLLLLLSLMSSMSSLSSLLSLMSLSSSSLLSLLLLSLSSMLLSSL 16352423 C1 LLMSMSLMLSSSSLLSSMLLSSLLMSSMSSLSLLLLSLMLMSSSMLSLLLLLSSSLLSLMS C2 LLMSMSLMLSSSSLLSSLLSLMSLMSSMSSLSLLLLLSMLMSSSMLSLLLLSLSSMLLSSL 16234523 D1 LLMSMSLMLSSSSLLSLLLLSLSSMLLSSLMLMSSSMLLMSSMSSLSLLLLLSSSLLSLMS D2 LLMSMSLMLSSSSLLSLLLLLSSSLLSLMSMLMSSSMLLMSSMSSLSLLLLSLSSMLLSSL

At this time, if the pitch noise computer simulation is performed on the pitch arrays applied on the entire circumference while considering the pitch group arrangements, the results shown in Table 4 can be obtained.

division Amplitude Dispersion sampling Relative ranking Conventional 6.08 Good 53.54% 9 A1 4.17 Good 51.72% 3 A2 3.88 Good 51.02% One B1 3.97 Good 51.55% 2 B2 4.95 Good 54.97% 8 C1 4.69 Good 56.24% 7 C2 4.25 Good 57.97% 4 D1 4.50 Good 54.43% 5 D2 4.67 Good 52.59% 6

As shown in Table 4, the most favorable arrangement for noise is an A2-type pitch array, which has a maximum amplitude level of 3.88, which is considerably reduced compared to 6.08 of the conventional pitch array, and the pitch noise computer simulation for the A2-type pitch array. The results of the experiment are shown graphically in FIG.

Therefore, when adopting the pitch arrangement like the A2 type made by the present invention for the pitch arrangement of P225 / 50R15 H409, the boundary of the mold division region is reduced so that the maximum amplitude level is nearly twice as shown in Figs. Is located on the boundary of the pitch, thereby eliminating traces in the mold partition area remaining after the tire is molded. In addition, developing and utilizing a computer simulation program can significantly reduce the tire pitch noise, as shown in Table 4, regardless of the location of the mold partition.

As described above, according to the present invention, by dividing the mold division region on the boundary of the pitch, it is possible to provide an optimum pitch arrangement structure that can remove the effect on the pitch noise caused by the trace of the mold division region, Ultimately, there is an effect to produce an optimal low noise tire that is favorable for noise.

Claims (3)

In a pitch arrangement having a tread composed of a number of basic pitches around the circumference of the tire, these pitches comprising at least three different sized pitches, Mold division region on the boundary of the pitch, (SL _max -SL _min ) ≤ {∑ (PL (i) × N (i))} × (10˚ / 360˚) Where SL _max is the maximum length of the mold partition, SL _min is the minimum length of the mold partition, PL (i) is the length of each pitch, and N (i) is the number of pitches for the length of each pitch. After each of the pitch groups are formed in accordance with the length, and the pitch groups are assumed to be one pitch, the pitch group arrays which are advantageous for noise are obtained by computer simulation, and the pitch group arrays are returned to the original. Pitch arrangement structure for noise reduction of a tire, characterized in that the pitch arrangement is applied to the entire circumference for the pitch length of the circumference, and the most favorable pitch arrangement is adopted by computer simulation. The method of claim 1, wherein for each length of the mold partition region, {∑ (PL (i) × N (i))}-π × D≤0.5 mm Where PL (i) is the length of each pitch, N (i) is the number of pitches for the length of each pitch, and D is the limit of tolerance on the circumference by the empirical formula, which is the overall diameter of the mold. Pitch array structure for noise reduction of tires. The pitch array structure of claim 1, wherein the number of mold divisions is 8 to 10. 10.