JPH05294102A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To reduce noise in a vehicle caused by cavity resonance sound in the inside cavity of a tire, by setting in the inside cavity of the tire a partition board with durability without being accompanied by weight increase. CONSTITUTION:A couple of side walls 2 and 2, and a tread 3 extending over both of side 'walls 2 and 2 stretch toroidally. A tire having an inside cavity 4 surrounded by inside walls of respective parts of these side walls 2 and 2 and the tread 3 has a structure of arranging on an inside wall thereof a thin elastic partition board 5 extending almost axially in the inside cavity 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire having a structure in which a thin elastic partition plate is provided in the tire inner cavity for the purpose of reducing vehicle interior noise caused by resonance noise in the tire inner cavity.

[0002]

2. Description of the Related Art There are the following conventional techniques for reducing vehicle interior noise caused by resonance noise in a tire cavity. (1) A sound absorbing material or a protrusion is added inside the tire to absorb a resonance sound. (2) A method of adding a sound absorbing material or the like to the wheel and providing a wheel with a shielding plate or an air chamber to prevent the occurrence of cavity resonance in the tire cavity or change the resonance frequency It is designed to reduce the peak level. The type (1) is to take countermeasures over the entire circumference in the tire circumferential direction, and the type (2) is to take countermeasures on the wheel side.

[0003]

By the way, the above (1)
The method of providing the sound absorbing material or the protrusion inside the tire is difficult to secure the durability of the sound absorbing material or the like because the inside of the tire lumen is largely deformed as the tire rolls. Since the protrusions and the protrusions must be installed over the entire tire circumferential direction, an increase in weight is inevitable, and there is a concern that fuel consumption will deteriorate. Furthermore, the method (2) of providing a sound insulating plate or air chamber on the wheel side is often a hindrance when assembling tires to the wheel, and there is a problem with the durability of the sound insulating plate.
Both (1) and (2) had drawbacks.

The present invention was devised to solve the above-mentioned drawbacks, and an object thereof is to provide a thin elastic partition plate extending substantially axially in the inner wall of the tire inner cavity. Therefore, it is an object of the present invention to provide a pneumatic tire that is durable and does not cause an increase in weight, and further that reduces the noise in the vehicle due to the cavity resonance inside the tire.

[0005]

In order to achieve the above object, in the pneumatic tire of the present invention, a pair of sidewalls and a tread portion extending over both sidewalls are connected in a toroidal shape. A tire having an inner cavity surrounded by inner walls of respective portions is provided with a thin elastic partition plate extending substantially axially inside the inner cavity of the tire.

[0006]

In general, the cavity resonance sound inside the tire, which is a problem in passenger cars, is a primary resonance sound of about 250 Hz.
The sound pressure distribution in the tire cavity is as shown in (a). That is, the sound pressure P is maximum (belly) at the ground contact portion with the road surface of the tire and the opposite portion thereof, and the sound pressure P is minimum (node) at a position ± 90 ° from the ground contact portion. Further, since the particle velocity u is 90 ° out of phase with the sound pressure, it has a maximum at a position of ± 90 ° from the ground contact portion. When a thin rubber plate is inserted as shown in FIG. 1 (b), at a position of ± 90 °, the particle velocity u decreases, the sound pressure P increases, the sound pressure mode of the entire tire lumen changes, and The overall force in the direction is reduced, resulting in a reduction in the in-vehicle noise level.

The following is a result of a tire vibration test as a basis for the above operation. (1) performs a vertical vibration in the tire contact state as vibration test of the tire (FIG. 1 (c)) FIG. 1 (c), the measured F / X ₀ (vertical dynamic stiffness) of the tire It was evaluated by the cavity resonance peak level. (2) Results (Fig. 1 (d)) As shown in Fig. 1 (b), two thin rubber plates are arranged, and the area covered by them is 15% of the tire cross-sectional area. When it was set to 3 mm, the cavity resonance peak level was reduced by 2 dB.

[0008]

EXAMPLES The present invention will now be described in detail with reference to examples. 2 is a cross-sectional view of an embodiment of the present invention, and FIG. 3 is a cross-sectional view of another embodiment. FIGS. 4A to 4D are views showing the manner of mounting the thin rubber plate 5 in FIGS. 2 and 3 in the tire lumen 4 in the circumferential direction. 5 (a), (b)
FIG. 6 is a diagram of a test on tire dynamic rigidity characteristics of the embodiment of the present invention and a test apparatus therefor.

The pneumatic tire shown in the embodiment is a conventionally known common pneumatic tire, the structure of which has a pair of beads spaced from each other at the base, and a carcass straddling between the beads. The carcass is folded back to the outside at the bead portion 7. A pair of sidewalls 2 and 2 is formed in the extended portion connected to it, and a tread portion 3 provided with a belt layer across the sidewalls 2 and 2 is formed in a toroidal shape. A thin rubber plate 5 is attached in a substantially axial direction in an inner cavity 4 surrounded by the sidewalls 2 and 2 and the inner walls of the tread portion 3. In the mounting mode, the thin rubber plate 5 is vertically fixed to the tire inner bottom wall 6 in the case of FIG. 2, and is fixed to the inner wall of the beat portion 7 in the case of FIG.

Further, the manner of mounting the thin rubber plate 5 in the tire circumferential direction is shown in FIGS. 4 (a) to 4 (d). In FIG. 4 (a), one sheet is provided in the inner cavity 4 of the tire, and FIG. ) Is 2
This is an example in which four sheets are mounted, (c) is four sheets, and (d) is six sheets. In the case of a plurality of sheets, they are installed at symmetrical positions in consideration of balance. As long as at least one thin rubber plate 5 is provided, it is possible to properly provide the thin rubber plate 5 as long as the effect can be obtained, and it is desirable to provide the thin rubber plates 5 at symmetrical positions. Reference numeral 8 is a wheel mounting hole.

Next, the tire size 22 according to the embodiment shown in FIG.
Applying to the test tire of 5 / 60R16, the following (I),
The test of (II) was carried out. (I) Test on tire dynamic stiffness characteristics In FIG. 5A, the tire cross-sectional area: S ₀ , the thin rubber plate area: S, the depth of the thin rubber plate from the tire bottom wall: h, and h is 0 mm, 25 mm , 45 mm and 70 mm, the relationship between S / S ₀ showing the tire dynamic rigidity characteristics and the cavity resonance peak level was examined, and it was as shown in FIG. 5 (b). According to it, 1/3 of the tire cross-sectional area
It has been found that the shielding of C can significantly reduce the cavity resonance peak level by 4 dB. Note that the tire dynamic rigidity characteristic represents the characteristic obtained by the method shown in FIG.

(II) Protrusion Override Test In order to see the improvement effect during rolling of the tire in the above case, as shown in FIG. Evaluated for power. The test conditions at that time were a speed of 60 km / h and a load of 39.
With a tire of 0 kg and a tire size of 225 / 60R16 and a thin rubber plate of 1/3 of the tire cross-sectional area, a reduction of 3.5 dB was confirmed at the sound pressure level.

[0013]

As described above in detail, since the pneumatic tire of the present invention is constructed, the pneumatic tire according to the present invention is conventionally provided with a thin elastic partition plate extending substantially axially in the inner cavity of the tire. In comparison with this type of tire, the durability can be improved without increasing the weight of the tire, and further, the reduction of the vehicle interior noise caused by the cavity resonance inside the tire can be easily achieved. is there.

[Brief description of drawings]

FIG. 1A is an auxiliary view for explaining the operation of the present invention. (B) is operation explanatory drawing of the pneumatic tire of this invention. (C) is the figure which showed typically the tire oscillating device used for operation confirmation of this invention. (D)
[Fig. 2] is a diagram showing test results by the device of Fig. 1 (c).

FIG. 2 is a sectional view of an embodiment of the present invention.

FIG. 3 is a sectional view of another embodiment of the present invention.

FIG. 4A is a circumferential sectional view in which one thin rubber plate according to an embodiment of the present invention is provided. (B) is a circumferential sectional view in which two thin rubber plates of the embodiment of the present invention are provided. (C) is a circumferential direction sectional view in which four thin rubber plates of the embodiment of the present invention are provided.
(D) is a circumferential direction sectional view in which six thin rubber plates of the embodiment of the present invention are provided.

FIG. 5 (a) is an explanatory diagram of a test relating to tire dynamic rigidity characteristics of the example of the present invention. (B) is a figure showing a test result based on (a).

FIG. 6 is an apparatus diagram in which a protrusion riding test of the pneumatic tire of the present invention is performed.

[Explanation of symbols]

 1 Pneumatic Tire 2 Sidewall 3 Tread Part 4 Lumen 5 Thin Rubber Plate 6 Tire Inner Bottom Wall 7 Bead Part 8 Wheel Mounting Hole

Claims (1)

[Claims] 1. A pair of sidewalls and a tread portion extending over both sidewalls are connected in a toroidal shape,
A pneumatic tire comprising a tire having an inner cavity surrounded by an inner wall of each of these portions, the inner wall of the tire being provided with a thin elastic partition plate extending substantially axially in the inner cavity.