JPH06206402A - Low road noise car tire - Google Patents

Abstract

PURPOSE:To reduce road noise without causing reduction of lowering properties of a car tire. CONSTITUTION:Al least one protruding edge section 3 whose width W1 extends in the peripheral direction of tire is 3 mm or more and whose height h is 0.5 mm or more is formed on at least one inner face side 2 in the scope C which extends from the position A at 2/3 of the width WT, from the center line P of tread width WT to the position B of the maximum tire width W.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic passenger car tire, and more particularly to measures for reducing road noise of a passenger car.

[0002]

2. Description of the Related Art Normally, when a vehicle travels on a rough road surface,
A large amount of noise is generated inside the vehicle. And this noise is what is called a so-called road noise phenomenon, and is generally well known as a go sound that occurs when running on uneven road surface, and this noise together with pattern noise as noise of the other tire. Prioritized for prevention.

By the way, the vibration source of the road noise is
It is believed that this is due to the unevenness of the road surface, and it is believed that the resonance system between the traveling vehicle and the tire that directly contacts the road surface is involved in this. That is, the resonance phenomenon between the suspension system on the vehicle side and the elastic vibration on the tire side and, in addition to this, the air column resonance in the passenger compartment are also mentioned as the resonance system. Here, when these vibrations are viewed in the frequency range, they are regarded as a mixed system of 30 to 60 Hz and 100 to 315 Hz as the minimum audible frequencies. The former is a so-called muffled sound, and the latter is a high-pitched sound as a kind of transmitted sound. Above all, countermeasures are urgently needed as shocking vibration noise particularly in the 250 and 315 Hz sound range.

As a countermeasure against the latter noise, various measures are taken not only on the tire side but also on the vehicle side. One of them is, for example, a liquid damping mount. As one of the measures on the tire side, for example, as one example, it has been proposed to control the vibration of the tire shoulder portion by reinforcing the belt edge portion inside the tire structure. Another problem is that the comfort and rolling resistance deteriorate.

[0005]

By the way, as a measure against road noise on the tire side so far, the purpose is mainly to reduce noise. Therefore, although the effect in this aspect can be achieved to some extent, on the other hand, However, there is the trade-off problem that the deterioration of tire characteristics must be sacrificed.

The present invention has been made in order to cope with the actual situation as described above, and an object thereof is to reduce the noise level without impairing the performance of the tire.

[0007]

[Means for Solving the Problems] In order to achieve the above object,
In order to reduce the noise level, the inventors of the present invention first conducted extensive research into the internal shape of the conventional tire and the mechanism of noise generation, and as a result, the shape and structure of the tire inner surface influence the cause of noise generation. Found the fact that
The present invention has been completed.

That is, the feature of the present invention which meets the above object is that at least one tire inner surface from the position of 2/3 of the tread width to the position of the maximum tire width in the tire circumferential direction. The structure is such that at least one protrusion having a width of 3 mm or more and a height of 0.5 mm or more is formed.

[0009]

According to the passenger car tire of the present invention having the above-mentioned basic structure, since the tire inner surface structure is formed with the ridge portion of a specific size extending in the tire circumferential direction at the specific position, the ridge portion is a tire. In a specific area from the tire shoulder to the side wall, which is considered to be the vibration source of road noise of the tire, a kind of reinforcing rib action is performed to control the noise generation due to the vibration of these parts of the tire during running. It is a thing. That is, the tone range of the noise has a remarkable effect in the frequency range of 250 to 315 Hz, and therefore, the noise reducing action in the high tone color range is confirmed. Along with this, the riding comfort and rolling resistance as tire performance are not a factor that impairs anything.

[0010]

Embodiments of the present invention will be described below with further reference to the drawings.

FIG. 1 shows a cross section of a low road noise passenger car tire according to the present invention, where 1 is the tread portion of the tire, the width of the tread portion 1 is W _T , and W is the maximum width of the tire. Show. As shown in the figure, the present invention is characterized in that, on the tire inner surface 2 side, the ridge portion 3 in the tire circumferential direction starts at a position A of 2/3 from the center line P of the tread width W _T , and from there, the tire. It extends at least on one side of the inner surface of the tire within a range C that ends in the end portion B of the maximum width. In this case, of course, the range C on both the left and right inner surfaces
It may be formed inside, but either one may also be formed. However, in order to further improve the road noise reduction effect, it is preferable to form them on both side portions. The number of the ridges 3 is 1
It may be an individual, but may be more.

On the other hand, the size of the ridge portion 3 is required to have a width w ₁ extending in the tire circumferential direction of 3 mm or more and a height h of 0.5 mm or more (see FIG. 2).

Further, with respect to the predetermined position of the ridge portion 3,
A position that is less than 2/3 of the center line P of the tread width W _T , that is, a position that is closer to the center inside A, and a position that is lower than the tire maximum width W end B, that is, a position closer to the bead wire 4. In both cases, the noise reduction effect is low. Further, as the size of the ridge portion 3, when the width w is less than 3 mm and the height h thereof is less than 0.5 mm, neither noise reduction effect is seen.

On the other hand, the width w ₁ is 30 mm.
In the case of the above, or even if the height h is 5 mm or more, the effect is not increased, but conversely the rolling resistance tends to deteriorate, which is not preferable.

Therefore, it is preferable that the width w _{1 of} the protrusion 3 is 30 mm or less and the height h thereof is 5 mm or less. Further, various shapes can be selected as the shape of the ridge portion 3, but there is sufficient room for selection as a design aspect within the range in which the effect can be exhibited.

Next, Table 1 shows the comparison test results of the road noise of the present invention shown in FIG. 1 and the conventional tires shown in FIGS. FIG. 3 is a graph showing the noise comparison test results of Experiment No. 7 and Experiment No. 11 (Comparative Example) in Table 1, and the solid line in the graph shows Experiment No. 11
, And the broken line shows Experiment No. 7, respectively.

Test conditions Noise test method: A microphone is installed near the center of the driver's ear and measured through a sound level meter. Tire Size: 185 / 65R14 85S rim size; 14 × 5.5 -jj in pressure; 2.0 kgf / cm ² load Weight; two + measuring instrument + vehicle weight speed; 60 km / h test vehicle; 2000cc test course; Toyo Tire & Rubber Company tire test course rolling resistance test method; speed 80km / h, 1.7m drum 35
0 kg, air pressure 2.0 kgf / cm ² (the smaller the value, the better). Margin below

[0018]

[Table 1]

In Table 1 above, Experiment Nos. 4 to 9 are examples of the present invention, and Experiment Nos. 1 to 3 and 10, 11 are comparative examples.

As is clear from Table 1, the position of the ridge portion 3 is within the range of the constitution of the present invention, that is, C (see FIG. 1).
It can be seen that when it is within the range, it is effective in reducing the road noise, and when the width w ₁ of the protrusion 3 is 3 mm or more and the height h is 0.5 mm or more, the same effect is obtained. . On the other hand, as is clear from the graph of FIG. 3, the tire of the example of the present invention has a noise level significantly lower in the frequency of 250 Hz belonging to high sound pressure than the conventional tire (Experiment No. 11). It can be seen that it is effective in reducing road noise.

[0021]

As described above, according to the low road noise passenger car tire of the present invention, on the tire inner surface in the range from the position 2/3 from the center line of the tread width to the position of the maximum tire width on the tire inner surface. The tire shoulder part is considered to be one of the causes of road noise because a rib of a specific size is formed to extend in the tire circumferential direction, that is, a kind of rib is formed on the inner surface of the tire. It is possible to achieve good control of the vibration source in the sidewalls, prevent an increase in the sound pressure level particularly near 250 Hz, and reduce road noise without impairing other performance of the tire.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a tire showing an embodiment of the present invention.

2 is a schematic partial enlarged view of the inner surface of the right shoulder portion of the tire in FIG.

FIG. 3 is a graph showing the results of a comparative test.

FIG. 4 is a schematic sectional view of a conventional tire.

5 is a schematic partial plan view showing the tire tread pattern of FIG. 4. FIG.

[Explanation of symbols]

1,11 Tread part 2 Inner surface side 3 Ridge part 4 Bead wire 5,15 Carcass 6,16 Belt A Position of 2/3 of tread width a Vertical groove B End of tire maximum width C Position of 2/3 of tread width To the position of the maximum width of the tire h Height of the ridge P Centerline of the tread width W Tire maximum width W _T Tread width w ₁ Width of the ridge

[Procedure amendment]

[Submission date] February 26, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

[0018]

[Table 1]

Claims (1)

[Claims] 1. A width of 3 mm or more and a height extending in the tire circumferential direction on at least one tire inner surface side in the range from the position of 2/3 of the tread width to the position of the maximum tire width. A low road noise passenger car tire characterized in that at least one ridge portion having a size of 0.5 mm or more is formed.