JP2001180216A - Assembly of pneumatic tire and rim - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce road noise. SOLUTION: In this assembly 1 of a pneumatic tire 2 and a rim 3, a tire inner cavity 4 is formed around the rim 3 by installing the tire 2 onto the rim 3. The assembly 1 has a noise damper 5. The noise damper 5 has a flexible annular band base body 6 mounted on the peripheral face of the rim 3; and one or more rising parts 7 formed in the band base body 6, rising to the tire radial direction from the peripheral face of the rim 3 by centrifugal force accompanying rotation of the assembly 1 to block the tire inner cavity 4. The band base body 6 has nearly U-shaped cutouts 14 each including a transverse cutout 13 continuously connecting between respective terminations G of a pair of longitudinal cutouts 12 each extending in an equal nearly circumferential direction from a starting point S. A cutout piece 11 sectionalized by the nearly U-shaped cutout 14 forms the rising part 7. The starting point S is formed with a bored part 16 for preventing stress concentration bored in a nearly circular shape.

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 rim and a pneumatic tire, which can reduce road noise during traveling while improving rim assembly.

[0002]

2. Description of the Related Art In recent years, there has been a demand for lower noise and quieter vehicles. There are various types of noise generated by tires.
The so-called road noise that generates a “go” sound in the frequency range of 400 Hz is transmitted to the inside of the vehicle and becomes a muffled sound in the vehicle interior, giving the passenger discomfort. As a result of various experiments by the inventors, such road noise is caused when the tire is mounted on the rim, the tire lumen formed around the rim and formed by a cavity surrounded by the tire and the rim forms an air column tube. It is known that the fact that the air is undergoing resonance vibration (cavity resonance) has a great effect.

[0003] The applicant of the present application has proposed, for example,
Japanese Patent No. 14682 proposes disposing a shield made of a spherical body in the tire cavity to suppress such resonance.

[0004]

However, in the above method, the spherical body has a cross-sectional area of, for example, 40% of the tire lumen.
Since it has a size that blocks the above, there have been problems such as deterioration of the balance of the tire and dropping off during transportation. The present invention has been devised in view of such a problem. A flexible annular band base is mounted on an outer peripheral surface of a rim, and a tire is mounted on the band base by centrifugal force accompanying rotation of an assembly. 1 to rise in the radial direction and block the tire lumen
It is an object of the present invention to provide an assembly of a pneumatic tire and a rim that can reduce road noise without impairing the rim assembly of the tire, based on the provision of the rising portion as described above.

[0005]

The invention according to claim 1 of the present invention is an assembly of a rim and a pneumatic tire in which a tire cavity is formed around the rim by mounting the pneumatic tire on the rim. A flexible annular band base attached to the outer peripheral surface of the rim; and one or more of the flexible bases provided on the band base and rising in the tire radial direction by centrifugal force accompanying rotation of the assembly to block the tire bore. And the band base has a substantially U-shape in which the ends of a pair of vertical cuts extending in the same substantially circumferential direction from the starting point are continuously joined by horizontal cuts. In addition to forming a U-shaped notch, the rising portion is formed by cut pieces partitioned by the U-shaped notch, and a cutout portion for preventing stress concentration, which is cut out in a substantially circular shape at the starting point, is provided. It is set to.

[0006] In such an assembly of a pneumatic tire and a rim, since the sound suppressor is constituted by a band base mounted on the outer peripheral surface of the rim, it does not hinder the rim assembling. There is no. In addition, during running, the rising portion provided on the band base rises in the tire radial direction due to centrifugal force, so that cavity resonance in the tire lumen can be suppressed and road noise can be reduced.

In addition, since the band base forms the rising portion when the cut piece partitioned by the substantially U-shaped notch rises due to centrifugal force, the noise control device has a simple configuration and is efficient. Can be configured. In addition, by providing a substantially circular hollowed-out portion for preventing stress concentration at the starting point of the U-shaped cut, even when the tire is repeatedly started up in the bore of the tire, stress concentration at the starting point is prevented. In addition, the durability of the noise control device can be significantly improved by suppressing breakage of the rising portion.

The band base is more effective in the tire bore when the plurality of cut pieces are formed in the tire circumferential direction and the cut pieces adjacent in the tire circumferential direction are displaced in the tire axial direction. This is preferable because resonance vibration can be suppressed and road noise can be greatly reduced.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of an assembly of a pneumatic tire and a rim (hereinafter, may be simply referred to as an “assembly”) according to the present embodiment, FIG. 2 is a perspective view illustrating the sound suppressor, and FIG. The partial plan view is shown. In the figure,
The assembly 1 is configured by mounting a pneumatic tire (hereinafter, may be simply referred to as a “tire”) 2 on a rim 3.
Tire bore 4 surrounded by tire 2 and rim 3 around rim 3
Is formed.

As shown in FIG. 1, the rim 3 of the present embodiment
Is a so-called two-piece wheel rim having, for example, a rim main body 3a on which the tire 2 is mounted and a disk 3b holding the rim main body 3a, and a bead portion 2a A rim bottom (also referred to as a well) 9 having a reduced outer diameter is formed in order to reduce the diameter. Further, the tire 2 of the present embodiment is mounted on the rim by mounting the bead portion 2a on the flange 10 of the rim main body 3a. The tire 2 is, for example, for a passenger car in which noise performance tends to be a problem, and has a tubeless structure in which a so-called inner liner rubber that hardly allows air to pass through is provided on the inner surface facing the tire cavity 4, and is airtight with the rim main body 3a. The tire cavity 4 is formed.

A sound suppressor 5 is mounted on the outer peripheral surface of the rim 3 in the tire radial direction. Sound suppressor 5 of the present embodiment
Is a flexible annular band base 6 mounted on the outer peripheral surface of the rim 3, and is provided on the band base 6. The centrifugal force accompanying the rotation of the assembly 1 causes the outer peripheral surface of the rim 3 to extend in the tire radial direction. One or more rising portions 7 that block the rising tire lumen 4
And is configured.

In the present embodiment, the band base 6 is made of, for example, a vulcanized rubber which is stretchable, and is expanded, for example, to form the rim 3.
In this example, the outer peripheral surface of the rim, that is, the outer peripheral surface of the rim bottom portion 9 in this example is attached while being closely attached in a slightly stretched state from one flange 10 side. The vulcanized rubber is not particularly limited, for example, natural rubber (NR),
Isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), nitrile rubber (NB
R) and diene rubbers such as chloroprene rubber (CR) are preferred. Particularly, NR, SBR and the like are preferable.

If the thickness of the band base 6 is too large, the tension at the time of mounting the rim tends to be too high, and the rim assembly tends to be deteriorated. There is a problem. From such a viewpoint, the band base 6 has, for example, a thickness of 0.5 to 3 mm, more preferably 0.5 to 2 mm, and still more preferably 1 to 2 mm (the thickness before the rim is attached). It is desirable. Further, as shown in FIGS. 2 and 3, the band base 6 exemplifies a band base 6 whose edges 6e, 6e in the width direction are substantially parallel and continuous with the same width BW (shown in FIG. 3). The width BW of the band base 6
Can be made substantially equal to the width of the rim bottom 9 of the rim 3, for example. Here, the width of the rim bottom portion 9 is, for example, a width RW (shown in FIG. 4) in which a small-diameter portion capable of dropping the bead portion 2a is substantially continuous. The band base 6 having such a width BW is mounted on the outer peripheral surface of the rim bottom 9 and has a small thickness.
It stays inside to prevent the rim assembly from getting worse. The rim bottom 9 may be inclined at a small angle with respect to the tire axial line.

When the band base 6 is made of vulcanized rubber as in the present embodiment, for example, the peripheral length La before the rim is attached,
The ratio (Lb / La) to the circumferential length Lb when the rim is mounted is 1.0.
And 1.3 or less, more preferably 1.08 to
1.16 is desirable. Thereby, an effective tightening force or frictional force for mounting the band base 6 on the outer peripheral surface of the rim 3 can be given, and the mounting of the band base 6 on the rim 3 becomes easy. If the ratio (Lb / La) is 1.0 or less, the band base 6 tends to loosen on the outer peripheral surface of the rim 3, so that the rising portion 7 becomes difficult to rise, and conversely, the ratio (Lb / La). ) Exceeds 1.3, a large tension acts on the band base 6 during or during attachment to the rim 3, so that the band base 6 tends to be cut and the durability tends to decrease.

The band base 6 of this embodiment has a longitudinal cut 12 extending inward from the widthwise edge 6e on both sides thereof at a distance X and extending in the same circumferential direction from the same position in the circumferential direction as a starting point S. A U-shaped cut 14 having a substantially U-shape that is continuously connected between G and G by a horizontal cut 13 is provided.
When the cut piece 11 partitioned by the U-shaped cut 14 rises by centrifugal force, the rising portion 7
Is formed. Thus, the rising portion 7 can be formed on the band base 6 with a simple configuration, efficiently and inexpensively, and the noise suppressor 5 can be configured. The rising portion 7 is not limited to the rubber-made cut piece 11 as long as it rises in the tire lumen 4 and does not allow air to pass through.

By setting the distance X to, for example, 2 mm or more, more preferably 3 mm or more, the strength of the edge portion between the vertical cuts 12 and 12 of the band base 6 and the width direction edge 6e can be maintained, and the durability can be improved. It is possible to prevent the property from being lowered. Further, at the starting point S of the vertical cuts 12, 12, stress is easily concentrated when the cut piece 11 rises due to centrifugal force, and by repeating these frequently, damage such as a crack is easily generated from the starting point S. Become. In order to prevent such damage, in the present embodiment, in order to prevent stress concentration on the starting point S, a hollow 16 is provided at the starting point. In this example, the hollow portion 16 has a circular shape having a diameter d with the center as the starting point S, and the diameter d is, for example, 2
~ 6 mm, more preferably 3-5 mm,
In addition to a circle, the shape may be an ellipse. Further, such a hollowed portion 16 is preferable in that the base 11a of the cut piece 11 on the starting point S side can be made small in width and the rigidity thereof is relatively weakened so that it can be more easily raised.

In the present embodiment, the rising portion 7
As shown in FIG. 2, at the time of rising, a plurality of tires arranged at substantially equal intervals in the tire circumferential direction, in this example, six tires are illustrated. By providing the plurality of rising portions 7 in this way, resonance in the tire lumen 4 can be more effectively suppressed, and it is useful to significantly reduce road noise during running. Also, by forming the rising portions 7 at substantially equal intervals in the tire circumferential direction,
For example, deterioration of the uniformity of the tire 2 can be prevented. The number of the rising portions 7 is not particularly limited, but is preferably, for example, 2 or more, more preferably 3 or more.

[0018] Such a noise suppressor 5 is used to connect the tire 2 to the rim 3.
When the rim is assembled, it is possible to attach the rim 3 to the outer peripheral surface of the rim 3 substantially flush.
Can be easily incorporated and the rim assemblability is not impaired.
In addition, while the assembly 1 is running, the noise suppressor 5
The rising portion 7 rises in the radial direction of the tire to block the air flow in the tire cavity, thereby suppressing cavity resonance and reducing road noise.

In the rising state of the rising portion 7, it is desirable to limit the height Ha in the tire radial direction, the width Wa in the tire axial direction, and the like. FIG. 4 illustrates a meridional sectional view of the assembly including the tire shaft when the tire is running under load. If the height Ha of the rising portion 7 is too small or the width Wa is too small, the effect of reducing the road noise is reduced. From such a viewpoint, the height Ha of the rising portion 7 is 85 to 100% of the tire lumen height H, which is the maximum height of the tire lumen when the tire is loaded, and the width Wa is the tire height when the tire is loaded. 20% or more of the maximum width W of the tire lumen is preferable in that the resonance in the tire lumen 4 can be more effectively prevented.

The normal running state of the tire under load varies variously depending on the load and the internal pressure. In this specification, “when the tire is running under load” refers to the case where the tire 2 is mounted on the normal rim 3 and the normal internal pressure is maintained. Filling and regular load of 74
% Is defined as the state when a load is applied and pressed against a flat surface. Here, the “regular rim” is a rim defined for each tire in the standard system including the standard on which the tire is based. For example, a standard rim for JATMA, a “Design Rim” for TRA, Or ETRTO
Then "Measuring Rim".

The "normal internal pressure" is the air pressure specified for each tire in the standard system including the standard on which the tire is based. The maximum air pressure for JATMA, and the table "TIRE" for TRA. LOAD LIMITS AT VARIOUS
Maximum value described in "COLD INFLATION PRESSURES", ETRT
If it is O, it is "INFLATION PRESSURE". However, if the tire is for a passenger car, the actual frequency of use etc. should be taken into consideration.
0 kPa. Further, the "regular load" is a load defined for each tire in the standard system including the standard on which the tire is based. For JATMA, the maximum load capacity, and for TRA, the table "TIRE LOAD LIMITS" AT VA
RIOUS COLD INFLATION PRESSURES "
For TRTO, use "LOAD CAPACITY".

The ratio (Ab / As) of the cross-sectional area As (when no load is applied) in the cross section including the tire axis of the tire lumen 4 and the cross-sectional area Ab of the rising portion 7 included in one tire meridian cross section. ) Is desirably 5% or more, 10% or more, more preferably 15% or more, and still more preferably 20% or more, in that the road noise can be more effectively reduced.

FIG. 5 shows another embodiment of the present invention. In the present embodiment, the band base 6 is exemplified by a plurality of band bases 6 arranged in the tire axial direction, and two band bases in the present embodiment. The two band bases 6A and 6B are mounted side by side in the tire axial direction on the outer peripheral surface of the rim 3 including the rim bottom 9 as shown in FIG. In the embodiments of FIGS. 5 and 6, three rising portions 7 of the two band bases 6A and 6B are formed for each band base, and are mounted on the rim 3 with their phases aligned in the tire circumferential direction. The following are examples. Note that the same reference numerals are given to the same portions of each band base 6 as described in the above embodiment.

In the case of this embodiment, on the three tire meridian sections, as shown in FIG. 6, two rising portions 7 can be raised simultaneously side by side in the tire axial direction, thereby shielding the tire cavity 4 in a wider area. Therefore, road noise can be further reduced. Further, in this example, the band base 6 may protrude from the rim bottom 9, but the thickness of the band base 6 is small, so that the rim assembling property is not significantly deteriorated. Although not shown, the phases of the band bases 6A and 6B may be shifted.

FIG. 7 shows still another embodiment of the present invention. The noise suppressor 5 of the present example is formed of a single band base 6, and a plurality of the cut pieces 11 are formed in the tire circumferential direction, and the cut pieces 11 A adjacent to each other in the tire circumferential direction are provided.
11B illustrates an example in which 11B is alternately displaced in the tire axial direction. In this embodiment, as shown in FIG. 8, it is effective to increase the number of the rising portions 7 while securing a large height Ha in the tire radial direction, and similarly efficiently shield the tire lumen 4. can do. The phase shift can be set variously.

[0026]

EXAMPLES Tires (195 / 65R15) and rims (15
× 6JJ, rim bottom width: 55 mm, rim bottom circumference: 1
10 cm), an assembly of a pneumatic tire and a rim was prototyped using the above sound suppressor, and the noise performance and the like were evaluated. For comparison, an assembly (comparative example) other than the present invention, such as an assembly from which a sound suppressor was removed, was also trial-produced and tested. The noise suppressor of this example has a single band base (Example 1).
6, 8) and two (Example 7). In the seventh embodiment, the phases of the rising portions are aligned (FIG. 5), and in the eighth embodiment, the rising portions are separated by a distance of about 15 cm in the tire circumferential direction.
Shifted (Fig. 7). The content of the test is as follows.

(Noise test) The rim was assembled at an internal pressure of 200 KPa and mounted on a 2000cc FR car manufactured in Japan. The speed of the road noise measurement road (asphalt rough road) was set to 6 by one passenger.
The sound inside the front seat when traveling at 0 km / H is passed through a 1/24 octave band filter to 226 Hz, 240 Hz,
The three-channel partial overall of 253 Hz was calculated, and evaluated by the increase / decrease value based on Comparative Example 1.

(Suitability of sound suppressor, rim assemblability) The wearability of the sound suppressor to the rim and the rim assemblability by hand assembly after attaching the sound suppressor to the rim were examined.

(Durability of the noise suppressor) The drum was run on the drum at an internal pressure of 200 KPa, a vertical load of 500 N, and a speed of 60 km / H, and the internal pressure was released every hour to confirm the degree of damage to the noise suppressor. Was visually inspected for the occurrence of cracks. After running for 10 hours, the goal was to eliminate cracks. Table 1 shows the test results and the like.

[0030]

[Table 1]

As a result of the test, it was confirmed that each of the assemblies of the embodiment reduced the road noise as compared with the conventional example. In addition, those of the examples were almost good in rim assemblability and durability. In Comparative Example 2, cracks occurred early in the vertical cut.

[0032]

As described above, according to the assembly of the present invention, the rising portion of the sound suppressor rises in the tire radial direction from the outer peripheral surface of the rim by using the centrifugal force. The cavity resonance of the tire lumen can be suppressed without impairing the tire, and the road noise can be greatly reduced.
Further, a U-shaped notch is provided in the band base, and the cut portion partitioned by the U-shaped notch rises by centrifugal force to form the rising portion. Therefore, the band is formed with a simple configuration, efficiently, and inexpensively. It can constitute sound equipment. Further, since a hollow portion for preventing stress concentration is formed at the starting point of the U-shaped cut, the durability of the rising portion can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a partial perspective view illustrating an assembly of a pneumatic tire and a rim according to an embodiment.

FIG. 2 is a perspective view illustrating a sound suppressor.

FIG. 3 is a partially developed view showing a band base in a developed state.

FIG. 4 is a cross-sectional view showing a state of the assembly during load running.

FIG. 5 is a development view of a band base showing another embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view including a tire shaft of an assembly using the same.

FIG. 7 is a development view of a band base showing another embodiment of the present invention.

FIG. 8 is a schematic cross-sectional view of an assembly using the same in a tire circumferential direction.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 assembly 2 pneumatic tire 3 rim 5 sound suppressor 6 band base 7 rising section 9 rim bottom 11 cut piece 12 vertical cut 13 horizontal cut 14 U-shaped cut 16 cutout section S Starting point of vertical cut G vertical cut End of cut

Claims (2)

[Claims] 1. An assembly of a rim and a pneumatic tire that forms a tire cavity around the rim by mounting the pneumatic tire on the rim, the flexible rim being mounted on an outer peripheral surface of the rim. A noise suppressor provided on the band base and having at least one rising portion that rises in a tire radial direction by a centrifugal force caused by rotation of the assembly and blocks a tire lumen; Is provided with a substantially U-shaped cut formed by continuously connecting the ends of a pair of vertical cuts extending in the same substantially circumferential direction from the starting point by a horizontal cut, and is partitioned by the U-shaped cut. An assembly of a pneumatic tire and a rim, wherein the raised portion is formed by the cut piece, and a cutout for preventing stress concentration is formed in the starting point so as to prevent stress concentration. 2. The band base according to claim 1, wherein a plurality of the cut pieces are formed in the tire circumferential direction, and the cut pieces adjacent in the tire circumferential direction are displaced in the tire axial direction. Assembly of pneumatic tires and rims.