JP2008302758A - Tire rim assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire rim assembly capable of securing tire uniformity performance without hindering the noise reducing effect and capable of preventing a fall of a noise absorbing member. <P>SOLUTION: A noise absorbing member 9 is formed from a non-woven fabric formed by twisting fiber filaments f each other, and an apparent specific gravity of the noise absorbing member 9 is 0.005 or more and less than 0.02. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a tire / rim assembly that provides a reduction in vehicle interior noise by providing a sound absorbing member in a tire cavity, and ensures tire uniformity performance without impairing the noise reduction effect. It relates to things that can prevent falling off.

  One of the causes of vehicle interior noise is that the air that fills the tire lumen, which is defined by the pneumatic tire and the applicable rim that is airtightly assembled with the pneumatic tire, is the tread that accompanies rolling rolling of the tire. It is mentioned that vibration is generated by the contact of the ground contact surface with the road surface unevenness to cause cavity resonance.

Therefore, in order to absorb such cavity resonance noise and reduce vehicle interior noise, each of Patent Documents 1 and 2 has a sound absorbing member made of a nonwoven fabric or sponge material fixed to the inner surface of a pneumatic tire. A technique has been proposed in which cavity resonance noise is reduced by arranging and returning vibration energy of filled air to heat energy inside the sound absorbing member.
Japanese Patent No. 3384633 Japanese Patent No. 3622957

  However, in the prior art, the apparent specific gravity of the sound absorbing member is not in the proper range, so that the weight of the sound absorbing member becomes too large, affecting the uniformity performance of the tire, and too light to secure shape stability. There was a problem of falling off the tire lumen. The present invention has been made in view of such problems, and while ensuring the tire uniformity performance without impairing the noise reduction effect, the sound absorbing member is prevented from falling off, and the tire lumen portion is stably provided. An object of the present invention is to provide a tire / rim assembly that can be fixed to a tire.

  The present invention relates to a tire / rim assembly in which a sound absorbing member made of a nonwoven fabric formed by entanglement of fiber filaments is disposed in a tire chamber defined by a pneumatic tire and an applied rim in which the pneumatic tire is hermetically assembled. A tire / rim assembly characterized in that the apparent specific gravity of the sound absorbing member is 0.005 or more and less than 0.02.

  According to the present invention, the apparent specific gravity of the sound absorbing member is 0.005 or more and less than 0.02, so that the tire uniformity performance can be ensured and the sound absorbing member can be prevented from falling off, and the apparent specific gravity is set to 0.005. If it is less than this, the shape of the sound absorbing member becomes unstable, and it is difficult to continuously fix it to the portion of the tire or rim facing the tire lumen, and there is a risk of falling off, while this is 0.02 In the case of exceeding the above range, the weight of the sound absorbing member is increased, and in particular, the non-uniformity in the connecting portion in the circumferential direction becomes remarkable, which may affect the tire uniformity.

  FIG. 1 is a partial schematic cross-sectional view in the tire width direction showing an embodiment of a tire / rim assembly according to the present invention in its rolling posture, in which 1 is the entire pneumatic tire, 2 is Applicable rims to which the tire 1 is assembled are shown respectively.

The pneumatic tire 1 includes a tread portion 3, a part of the sidewall portion 4 that is continuous to each side portion of the tread portion 3, and a bead portion 5 that is continuous to the inner peripheral side of each sidewall portion 4. These parts are reinforced by a carcass 6 extending in a toroidal shape between the bead parts to form a tire skeleton, and the tread part 3 is further reinforced by a belt 7 disposed on the outer peripheral side of the crown region of the carcass 6. .
In the figure, W represents the tread contact width, and E represents the tire equator plane.

  Further, the tire 1 here further includes, for example, an impregnation layer or other adhesive layer 10 obtained by melt-impregnating a sound absorbing member 9 made of a non-woven fabric formed by entanglement with the inner surface of the inner liner 8 and fiber filaments. With the equator plane E as the center, for example, it is fixed over the entire circumference of the inner liner 8 or only in a part in the circumferential direction.

  In addition to the case where the sound absorbing member 9 is affixed to the inside of the tread portion, the sound absorbing member 9 may be fixed to the sidewall portion 4 or the inner surface of the bead portion 5 as indicated by a two-dot chain line in FIG. Further, the sound absorbing member 9 may be attached to the inner surface of the rim 2.

  Here, the sound absorbing member 9 made of non-woven fabric has a width within a range corresponding to 30 to 100% of the tread contact width W with the tire equator plane E as the center, as illustrated in an enlarged cross-sectional view in FIG. It is preferable to have such that the excellent sound absorption effect can be exhibited without impairing the durability of the tire. Moreover, it is preferable that the thickness t be in the range of 0.5 to 50 mm from the viewpoint of exhibiting an excellent sound absorbing effect and ensuring the durability of the sound absorbing material. If the thickness is less than 0.5 mm, the sound absorbing effect is obtained. When the thickness exceeds 50 mm, deformation due to centrifugal force during high-speed rotation increases due to an increase in mass, and the possibility of occurrence of peeling or the like increases.

  In the above description, the “tread contact width” means that a pneumatic tire is mounted on an applicable rim and filled with a specified air pressure, and the tire is statically placed on a flat plate in a straight posture to achieve a specified mass. The maximum linear distance in the tire axial direction at the contact surface with the flat plate when a corresponding load is applied.

  In the above description, “applicable rim” refers to a rim defined in the following standards according to the tire size, and the standard refers to an industrial standard effective in the area where the tire is produced or used. For example, “YEAR BOOK of THE TIRE AND RIM ASSOCIATION INC.” In the United States, “STANDARDS MANUAL of THE European Tire and Rim Technical Organization” in Europe, “JATMA YEAR BOOK” of the Japan Automobile Tire Association in Japan It is. The “specified air pressure” means the air pressure specified in accordance with the maximum load capacity in the following standards. The maximum load capacity is the maximum allowable load on the tire in the following standards. Of mass. The “specified mass” refers to the above maximum load capacity. The air here can be replaced with an inert gas such as nitrogen gas or the like.

  The present invention is characterized in that the apparent specific gravity of such a sound absorbing member 9 is 0.005 or more and less than 0.02, and by making this less than 0.02, tire uniformity performance is secured, By setting this to 0.005 or more, it is possible to stabilize the shape of the sound absorbing member and prevent the sound absorbing member from falling off the tire.

  A sound absorbing member consisting of polyethylene terephthalate fiber filaments (mass per filament length of 6 dtex) and having the dimensions shown in Table 1 is continuously applied to the inner liner of a pneumatic tire of size 215/45 R17. The tire is bonded to the inner surface of the tire with double-sided tape and attached to the vehicle by assembling it on the rim of 7.55J, and this vehicle is mounted on asphalt under conditions of air pressure 210kPa, load 3.92kN, speed 60km / h. The vehicle was run on the road surface, and the noise inside the driver's seat was measured and analyzed for frequency. The peak seen around 230 Hz is the peak of the cavity resonance sound, and the sound pressure in this frequency band was measured to compare the differences between the sound absorbing members. Further, the same measurement is performed for the case where no sound absorbing member is used, and this is set as Comparative Example 1, and the measurement results of the respective Examples and Comparative Examples are obtained as the sound reduction effect (sound pressure difference) with respect to Comparative Example 1. The sound reduction effect is shown in Table 1 as an index with the sound reduction effect of Comparative Example 4 as compared to Comparative Example 1 being 100. The larger the value, the greater the sound reduction effect.

  The sound absorbing members are all 100mm wide (60% of the tread contact width) and all 28mm thick. However, the apparent specific gravity is different for each of the examples and comparative examples, and therefore the mass of the sound absorbing member is changed. It was.

  For each tire, RFV, which is a representative item of tire uniformity, was measured, the weight of the tire was measured, and the shape of the sound absorbing member was stably maintained as an evaluation of the shape stability of the sound absorbing member. Whether or not pasting (fixing) was possible was examined.

  For RFV, in Table 1, “○” is added when the measured value is less than 15% of the measured value of Comparative Example 1 without the sound absorbing member, and “X” is added when the measured value is 15% or more. expressed. The weight of the tire is shown in Table 1 as an increment relative to Comparative Example 1 where no sound absorbing member is attached. Also, whether or not the sound absorbing member can be pasted (fixed) is shown in Table 1 as “X” when pasting is not possible. Is indicated by “◯”.

  As is clear from Table 1, although the examples have no difference in the sound reduction effect as compared with the comparative examples, both the applicability and the RFV show satisfactory results. In Comparative Example 2, the RFV and the sound reduction effect could not be measured because this could not be attached to the tire.

It is a partial approximate line sectional view showing an embodiment of this invention. It is a principal part expanded sectional view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Rim 3 Tread part 7 Belt 8 Inner liner 9 Sound absorbing member 10 Adhesive layer W Tread grounding width E Tire equatorial surface t Thickness f Fiber filament

Claims (1)

In a tire / rim assembly in which a sound absorbing member made of a nonwoven fabric formed by entanglement of fiber filaments is disposed in a tire chamber defined by a pneumatic tire and an applied rim in which the pneumatic tire is airtightly assembled,
A tire / rim assembly characterized in that the apparent specific gravity of the sound absorbing member is 0.005 or more and less than 0.02.

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