JP2003048407A - Assembly of pneumatic tire with rim - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the road noise without impairing a rim assembly property. SOLUTION: A strip-like sheet 5 for noise insulation having the volume S2 of >=0.4% of the total volume S1 of an inner cavity of a tire and using a sponge is disposed in the inner cavity 4 of the tire. At least one surface 5S of the strip-like sheet 5 forms an uneven surface 10 in which a recessed portion 10A and a projecting portion 10B are repeatedly arranged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assembly of a pneumatic tire and a rim which can reduce road noise during traveling without impairing the rim assembling property.

[0002]

2. Description of the Related Art One of tire noises is 50 to 400 Hz when traveling on a road surface.
There is so-called road noise that causes a "go" noise in the frequency range of 1), and the main cause thereof is resonance vibration of air (cavity resonance) that occurs in the tire lumen.

Therefore, the present applicant has filed Japanese Patent Application No. 2000-26.
In No. 3519, it is proposed to dispose a sound-suppressing strip-shaped sheet using a sponge material in the tire inner cavity.
The volume S2 of the strip-shaped sheet is calculated by dividing the total volume S1 of the tire lumen by S1.
Cavity resonance can be effectively suppressed by setting the ratio to 0.4% or more.

The present invention relates to an improvement of the strip-shaped sheet, wherein at least one surface of the strip-shaped sheet is an uneven surface in which a concave portion and a convex portion are repeated, or the strip-shaped sheet is made of a first sponge material excellent in sound absorbing performance. It is possible to further enhance the effect of suppressing the cavity resonance and to reduce the road noise, based on the multilayer structure of the first layer consisting of the above and the second layer consisting of the second sponge material excellent in the sound reflection preventing performance. An object of the present invention is to provide a pneumatic tire / rim assembly that can be significantly reduced.

[0005]

In order to achieve the above-mentioned object, the invention of claim 1 of the present application relates to a tire inner cavity formed by a rim and a pneumatic tire mounted on the rim. A sound-suppressing strip-shaped sheet having a volume S2 of 0.4% or more of the total volume S1 and using a sponge material is arranged, and at least one surface of the strip-shaped sheet is an uneven surface in which concave portions and convex portions are repeated. It is characterized by that.

According to a second aspect of the present invention, the rim and the pneumatic cavity of the pneumatic tire mounted on the rim have a volume S2 of 0.4% or more of the total volume S1 of the tire cavity. And a band-like sheet for noise control using a sponge material is arranged, and the band-like sheet comprises a first layer made of a first sponge material having excellent sound absorbing performance and a second sponge having excellent sound reflection preventing performance. It is characterized in that it is a multilayer structure with a second layer made of a material.

In the present specification, the "volume S2 of the strip-shaped sheet" is the apparent total volume of the strip-shaped sheet and is defined by the outer shape of the strip-shaped sheet including the holes of the sponge material. . Further, the "total volume S1 of the tire bore" is approximately obtained by the following equation (1) in the normal state of the assembly. S1 = A × {(Di−Dr) / 2 + Dr} × π (1) In the formula, “A” is a cross-sectional area of the tire bore obtained by CT scanning the tire bore in the normal state, and “Di”. Is the maximum outer diameter of the tire bore in the normal state shown in FIG.
r "is the rim diameter, and" π "is the circular constant.

The "regular state" means a state in which the assembly is filled with a regular internal pressure and is not loaded. In addition, "regular internal pressure" is the air pressure that each standard defines for each tire in the standard system including the standard on which the tire is based. VARIOUS COLD INFLATION P
The maximum value described in "RESSURES" or "INFL" for ETRTO
ATION PRESSURE ", but if the tire is for passenger cars, it is set to 200 kPa in consideration of actual usage frequency.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a meridional sectional view of an assembly of a pneumatic tire and a rim (sometimes referred to simply as “assembly”) of the present invention, and FIG. 2 is a schematic sectional view in the circumferential direction along the tire equatorial plane of the assembly. Shows.

In FIG. 1, an assembly 1 has a pneumatic tire 2 (sometimes simply referred to as "tire 2") mounted on a rim 3 so that the tire 2 and the rim 3 are surrounded by the rim 3.
Forms a tire lumen 4 surrounded by and.

As shown in FIG. 1, the rim 3 of the present embodiment.
Is a rim body 3a to which the tire 2 is mounted,
A so-called two-piece wheel rim having a disc 3b holding the rim body 3a is exemplified. Further, the tire 2 of the present embodiment is, for example, a radial tire for a passenger vehicle in which a bead portion 2a is closely attached to a flange 3a1 of a rim body 3a, and is a radial tire for a passenger car. An example is a tubeless structure in which an inner liner rubber is attached, and an airtight tire lumen 4 is formed with the rim body 3a.

Further, in the assembly 1 of this embodiment, a band-like sheet 5 for noise reduction using a sponge material is arranged in the tire inner cavity 4. The strip-shaped sheet 5 can be arranged in the tire inner cavity 4 in a free state in which it is not fixed to either the tire 2 or the rim 3, but is preferably fixed to one of the tire 2 or the rim 3. In this example, a case where a synthetic rubber adhesive is used to adhere to the tire inner surface 4S under the tread is illustrated.

Next, the sponge material forming the belt-like sheet 5 is a sponge-like porous structure, for example, a so-called sponge having open cells formed by foaming rubber or synthetic resin, and animal fiber, plant fiber or synthetic fiber. Includes those that are entangled with each other and integrally connected.

The "porous structure" referred to in this specification includes not only open cells but also closed cells. Since such a sponge material has high vibration damping and sound absorbing properties, it can effectively absorb the sound energy generated in the tire inner cavity 4, and can suppress the cavity resonance to reduce the road noise. In addition, the sponge material is easy to deform such as shrink and bend, so it does not impair the rim assembly property, and its specific gravity is much smaller than that of a solid rubber body, so it has a low adverse effect on the tire weight balance. sell. In this example, a preferable example using an open-celled sponge material made of polyurethane is illustrated.

The sponge material is not particularly limited, but its specific gravity is 0.005 to 0.06, more preferably 0.010 to 0.05, still more preferably 0.016.
˜0.05, particularly preferably 0.016 to 0.035. If the specific gravity is less than 0.005 or more than 0.06, the effect of suppressing cavity resonance tends to decrease.

What is important here is that the volume S2 (specified as described above) of the belt-shaped sheet 5 is set to the tire in order to exert the effect of suppressing the cavity resonance by the belt-shaped sheet 5, that is, the effect of reducing the road noise. It is necessary to secure at least 0.4% of the total volume S1 of the lumen (specified as described above).

This is based on the results of various experiments conducted by the inventors of the present invention. In FIG. 7, the raw material and the specific gravity of the sponge material of the belt-shaped sheet 5 are the same, and the total volume S1 of the tire bore 4 is the same. A test result when a road noise test is performed by changing only the volume S2 of the belt-shaped sheet 5 is shown.

As shown in FIG. 7, there is a clear correlation between the ratio S2 / S1 and the road noise, and the ratio S2 / S1 is 0.0
When it is 04 or more, the required road noise reduction effect is exhibited. For this road noise reduction effect,
The ratio S2 / S1 is preferably 0.01 or more, more preferably 0.02 or more, and further preferably 0.04. When the ratio S2 / S1 exceeds 0.2, not only the road noise reducing effect reaches its peak, but also unnecessary increase in weight and cost or reduction in weight balance is caused. Therefore, the upper limit is preferably 0.1 or less.

From this point of view, the strip-shaped sheet 5 is
Is not particularly limited as long as the volume S2 satisfies the above range, and the length L1, the width W1, the thickness T1 and the like are not particularly limited. To be attached to the rim or to the rim, etc.)
It is appropriately set according to the above. Normally, the length L1
In general, the length is 20 mm or more and not more than one circumferential length of the inner surface of the tire. The width W1 is generally 20 mm or more and the tire ground contact width +40 mm or less. Also thickness T1
Generally, it is 3.0 mm or more and 80% or less of the tire cross-section height.

In the first invention of the present application, in order to further enhance the effect of suppressing the cavity resonance by the belt-shaped sheet 5, at least one surface of the belt-shaped sheet 5, in this example, the surface 5S facing the tire inner cavity 4, As shown in FIG.
It is formed by the uneven surface 10 in which A and the convex portion 10B are repeated.

Such an uneven surface 10 has an excellent antireflection effect such as softening the reflection of sound, and further enhances the effect of suppressing the cavity resonance in combination with the increase of the surface area of the sponge material in contact with the sound. You can

As the uneven surface 10, as shown in FIG. 3, there is no smooth surface portion, and in addition to a wavy surface in which a projecting convex portion 10B and a concave concave portion 10A are smoothly repeated, for example, as shown in FIG. As shown in FIGS. 4 (A) and 4 (B), the smooth surface portion 11 is interspersed with projection-like convex portions 10B (at this time,
The smooth surface portion 11 corresponds to the recess 10A. Alternatively, a smooth surface portion 11 having dimple-shaped concave portions 10A scattered therein (at this time, the smooth surface portion 11 corresponds to the convex portion 10B) can be employed. In FIG. 4B, the recesses 10A may be formed randomly by peeling by hand, and at this time, the shape and size of each recess 10A may be different for each recess.

Furthermore, the uneven surface 10 is shown in FIG.
As shown in (C) to (C), the rib-shaped convex portion 1 is formed on the smooth surface portion 11.
0B arranged (at this time, the smooth surface portion 11 has the concave portion 10A).
Equivalent to. ), In which a groove-shaped concave portion 10A is provided in the smooth surface portion 11 (at this time, the smooth surface portion 11 corresponds to the convex portion 10B), or without the smooth surface portion 11, the rib-shaped convex portion 10B and the groove-shaped concave portion 10A are provided. It is also possible to employ one in which the concave portion 10A is smoothly repeated.

Here, the surface area Sb of the uneven surface 10 is
Then, it is preferable that the ratio Sb / Sa of the surface 5S to the surface area Sa when the surface 5S is assumed to be a smooth surface without unevenness is in the range of 1.04 to 5.00. This is because, as will be seen from Tables 1 to 3 described later, the effect of further suppressing the cavity resonance by the uneven surface 10 is exhibited when the ratio Sb / Sa exceeds 1.04, and is approximately 5.00. This is because it saturates and no further effects can be expected.

As for the height h2 of the uneven surface 10 and the pitch h3 of the uneven surface, the surface area ratio Sb / Sa is within the above range 1.04.
If it is in the range of to 5.00, it is not particularly restricted,
Generally, in order to prevent sound reflection, the uneven height h2
Is preferably 5 mm or more, and more preferably 10 mm or more.

Next, in the second invention of the present application, in order to enhance the effect of suppressing the cavity resonance by the strip-shaped sheet 5, the strip-shaped sheet 5 is formed into a first sponge excellent in sound absorbing performance as shown in FIG. The first layer 5A made of a material and the second layer 5B made of a second sponge material having an excellent antireflection property of sound are formed as a multilayer structure.

It is generally known that a sponge has a trade-off between sound absorption performance and sound reflection prevention performance. Therefore, the strip-shaped sheet 5 is used as the multilayer structure, and the second layer 5 is used.
By arranging B so as to face the tire inner cavity 4, the sound absorption performance and the sound reflection prevention performance are maximized, and the effect of suppressing the cavity resonance can be further improved.

Here, as the second sponge material which is excellent in the antireflection property of sound, it is possible to preferably use a material in which the expansion ratio is greatly increased and the specific gravity is reduced as compared with the first sponge material. At this time, it is necessary to reduce the ratio α2 / α1 between the specific gravity α1 of the first sponge material and the specific gravity α2 of the second sponge material to 0.7 or less, further 0.5 or less for the antireflection property of sound. Preferably, the thickness t of the second layer 5B is set to the strip sheet 5
It is preferable to keep the total thickness T1 in the range of 0.05 to 0.3 times for sound absorbing performance.

As the second sponge material excellent in the antireflection property of sound, glass wool, felt material, and foam rubber may be used.

The multi-layer structure can be easily formed by adhering and integrating the first layer 5A and the second layer 5B. At this time, the layer of the adhesive reflects sound and causes cavity resonance. May interfere with the suppression effect of. Therefore, the area Sc of the adhesive layer is preferably suppressed to 0.05 times or less of the surface area Sa. The multi-layer structure can be formed not only by adhering the first layer 5A and the second layer 5B, but also by changing the compounding ratio of the foaming agent and changing the foaming ratio in one sponge.

The surface of this multilayer structure, that is, the second layer 5
The surface of A can be formed as the uneven surface 10 in which the concave portions 10A and the convex portions 10B are repeated, as in the first invention. In such a case, the antireflection property of sound is further enhanced, and the effect of suppressing cavity resonance can be further improved.

The strip-shaped sheet 5 may be attached to the rim 3, and in such a case, it may be fixed by using a screw or the like in addition to an adhesive.

Although a particularly preferred embodiment of the present invention has been described above in detail, the present invention is not limited to the illustrated embodiment and can be modified into various modes.

[0034]

EXAMPLE An assembly of a tire (195 / 65R15) and a rim (15 × 6JJ) having the structure shown in FIG. 1 and having the specifications shown in Tables 1 and 2 was prototyped and tested for road noise performance.

The belt-like sheet has a single layer structure of polyurethane sponge (open cells) having a specific gravity of 0.022 in Comparative Examples 1 and 2 and Examples 1 to 12, and has a specific gravity of 0.022 in Examples 13 to 16. It was formed as a multilayer structure of a first layer of polyurethane sponge (open cells) and a second layer of polyurethane sponge (open cells) having a specific gravity of 0.010. The contents of the test are as follows.

(1) Road noise performance; internal pressure 200 kP
The sound inside the front seat when the rim is assembled at a and installed on all wheels of a vehicle (FF of 2000 cc domestic), and a road noise measurement road (asphalt rough road) is run by one person at a speed of 60 km / H. The sound pressure level of the peak value of the air column resonance sound near 245 Hz is increased / decreased (dB
(A)) evaluated. -(Minus) display means reduction of road noise.

[0037]

[Table 1]

[0038]

[Table 2]

As in the case of comparing the conventional example with the comparative examples 1 and 2, it is possible to obtain 3.9 even by disposing a smooth strip-shaped sheet having no uneven surface.
Road noise of up to 4.6 dB can be reduced. However, as can be seen from the comparison between Comparative Example 1 and Examples 1 and 2, and the comparison between Comparative Example 2 and Examples 3 to 12, the surface of the strip-shaped sheet is made uneven to further reduce road noise. You can. In particular, as can be seen from Examples 3 to 12, the effect of the uneven surface is exhibited when the surface area ratio Sb / Sa of the sponge material exceeds 1.04.

Similar to the comparison between Comparative Example 1 and Examples 13 to 16, by forming the surface of the strip-shaped sheet with a sponge material having an excellent antireflection property of sound, the road noise reduction similar to that of the uneven surface can be achieved. The effect is expected. At this time, as can be seen from Examples 13 to 15, the smaller the area of the adhesive layer, the higher the road noise reduction effect.

Further, as in the sixteenth embodiment, by combining a sponge material having an excellent anti-reflection property of sound and an uneven surface, it is possible to further improve the road noise reducing effect.

[0042]

As described above, according to the present invention, at least one surface of the strip-shaped sheet is an uneven surface, or the strip-shaped sheet has a first layer made of a first sponge material having excellent sound absorbing performance and a sound reflection preventing performance. It is a multilayer structure with a second layer made of an excellent second sponge material. Therefore, the effect of suppressing the cavity resonance can be further enhanced by the synergistic effect with the sound absorbing performance and the sound reflection preventing performance, and the road noise can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a meridional sectional view showing an embodiment of an assembly of a pneumatic tire and a rim of the present invention.

FIG. 2 is a circumferential sectional view along the tire equator.

FIG. 3 is a perspective view showing an example of an uneven surface of a strip-shaped sheet.

FIG. 4A and FIG. 4B are perspective views showing still another example of the uneven surface.

5A to 5C are perspective views showing still another example of the uneven surface.

FIG. 6 is a perspective view illustrating a case where the strip-shaped sheet is formed of a multilayer structure.

FIG. 7 is a diagram showing a relationship between a volume ratio S2 / S1 and road noise.

[Explanation of symbols]

2 tires 3 rims 4 tire lumen 5 strip sheets 5A 1st layer 5B second layer 10 uneven surface 10A recess 10B convex part

Claims (3)

[Claims] Claim: What is claimed is: 1. A tire bore formed by a rim and a pneumatic tire mounted on the rim, and a total volume S of the tire bore.
A band-shaped sheet for noise suppression having a volume S2 of 0.4% or more of 1 and using a sponge material is arranged, and at least one surface of the band-shaped sheet is an uneven surface in which a concave portion and a convex portion are repeated. A characteristic pneumatic tire and rim assembly. 2. A tire bore formed by a rim and a pneumatic tire mounted on the rim has a total volume S of the tire bore.
A band-shaped sheet for noise control having a volume S2 of 0.4% or more of 1 and using a sponge material is arranged, and the band-shaped sheet is a first layer made of a first sponge material having excellent sound absorbing performance. An assembly of a pneumatic tire and a rim, which is a multi-layered structure including a second layer made of a second sponge material having excellent sound reflection preventing performance. 3. The pneumatic tire and rim assembly according to claim 2, wherein the second layer has an uneven surface on which a concave portion and a convex portion are repeated.