JPH01115701A - Low noise tyre wheel - Google Patents

Abstract

PURPOSE:To enable the peak of road noise due to the resonance of an air charging chamber to be dissolved under high durability by forming the air charging chamber inside of a rubber tyre and as well forming a cavity portion intercommunicating with the air charging chamber in a spoke. CONSTITUTION:A low noise tyre wheel is composed of a rubber tyre 1 of hollow toroid form, a rim 3 with a flange restraining the bead portion of the rubber tyre 1 and a spoke 5 by which the rim 3 is connected to a disc. Inside of the rubber tyre 1, an air charging chamber 4 is formed, and as well in the spoke 5, is formed a cavity portion 6 which is intercommunicated with the air charging chamber 4 through a communicating portion 7. With this arrangement, acoustic wave energy in the air charging chamber 4 is converted to acoustic wave energy in the cavity portion 6 so as to restrain the resonance of the air charging chamber 4. Accordingly, the peak of road noise due to the resonance of the air charging chamber 4 can be dissolved under high durability without damaging tyre motion performance.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a low-noise tire wheel with high vibration riding comfort performance.

The so-called harshness (I
larshness), as well as Road Roar (Road
Roar) or Road Rumb
Road noise (Rgad No1s) also called
e), and the latter in particular covers a frequency range of 100 to 400 Hz, but in the case of pneumatic radial tires for passenger cars, road noise often peaks around 250 Hz, which significantly impairs vibration ride quality.

This noise peak occurs due to the resonance of the air in the cavity between the inner surface of the tire and the outer periphery of the rim, and suppressing this noise peak to a low level is effective in improving the vibration riding comfort performance.

(Prior Art) As a technique for suppressing the resonance of the air in the cavity of a tire, Japanese Patent Application Laid-Open No. 62-50203 discloses that a resonance blocking material is sealed in the cavity of the tire to suppress the propagation of air signals. ing.

(Problem to be Solved by the Invention) This technology is effective in suppressing the resonance of the air inside the tire cavity, but the resonance suppressing material deforms due to centrifugal force during tire transfer and deformation of the tire when touching the ground. The problem was that the durability was poor due to repeated damage.

It is also effective to provide a sound absorbing layer on the inner surface of the tire.
This often has a negative effect on the tire's driving performance.

Therefore, it is an object of the present invention to provide a highly durable, low-noise tire wheel that suppresses the resonance of the air within the cavity of the tire.

(Means for Solving the Problems) The present invention converts the resonance energy of the air in the tire cavity into the resonance energy in the cavity provided in the spokes, thereby improving the air inside the tire cavity. This suppresses the occurrence of resonance.

That is, this invention consists of an assembly consisting of a rubber tire in the shape of a hollow toroid, a rim having a flange that suppresses the bead of the rubber tire, and spokes that connect the rim to a disk, communicating with an air-filled chamber inside the rubber tire. This is a low-noise tire wheel with hollow parts inside the spokes.

In this invention, the communication path between the air filling chamber of the tire and the hollow part in the spoke has a cross section smaller than the cross section of the hollow part in the spoke, specifically, has a cross section with an area of 1/3 or less, and It is preferable that the number of spokes provided with a cavity is three or more, and the volume of the cavity in one spoke is 1/10 or less of the volume of the air-filled chamber of the tire.

Furthermore, in implementation, the cavity inside the spoke is calculated using the following formula (+
It is desirable that the resonant frequency r according to ) satisfies the following formula (2).

Note: Here, C: Speed of sound in the tire (m/s) S: Cross-sectional area of the communication passage (rrr) ■: Volume of the sub-air filling chamber (e) L: Length of the communication passage (m) d: Communication passage Diameter (m) C/L≦f<C#!・(2) Here, L:
Circumference of the tire at the center of the tread (m) l: Circumference of the rim well (m) FIG. is the rim, 4 is the air filling chamber consisting of the tire cavity, 5 is the spoke, and 6 is the rim.
is a cavity in the spoke 5, and 7 is a communication path connecting the air-filled chamber 4 and the cavity 6.

FIG. 2 also shows a sound absorbing layer 8 on the inner wall of the cavity 6 of the spoke 5.
An example is shown below.

Furthermore, Figures 3 (a) to C) show the wheels before tie + installation, respectively, with 5 spokes in Figure 3 (a), 4 spokes in Figure 3 (B), and 4 spokes in Figure 3 (C). Similarly, there are three examples.

(Function) A noise problem in the resonance of the air inside the tire cavity is the first-order resonance in which the sound pressure is in opposite phase between the ground contact side of the tire and the upper side that faces the axle.

This invention converts the sonic energy in the air-filled chamber of the tire into the sonic energy in the hollow portions of the spokes, thereby suppressing resonance in the air-filled chamber.

Resonance within the tire cavity is particularly greater than the value C/L, which is the sound speed C divided by the circumference of the center of the tire tread, and is greater than the value C/Il, which is the sound speed C divided by the circumference 2 of the rim well. Since this occurs in a small frequency range, it is advantageous to provide a cavity with a resonant frequency matched to this frequency range. Specifically, the cavity may be designed so that the resonance frequency f according to the above equation (1) satisfies the above equation (2).

Furthermore, if a sound-absorbing layer is present in the cavity inside the spoke, energy will be absorbed and an even greater effect will be obtained. As the sound absorbing layer, a porous sound absorbing material such as urethane foam can be considered, for example.

On the other hand, it is advantageous to make the volume of the cavity in the spoke less than 1/10 of the volume of the air-filled chamber in the tire.This means that if the volume exceeds 1/10, the cavity in the spoke This is because there is an adverse effect due to the resonance of the parts. Figure 4 shows the sound pressure inside the tire when a part of the tire tread center is excited at the resonance frequency of the tire cavity, measured by a microphone at a position directly opposite to the point of vibration, and the horizontal axis is the sound pressure inside the tire. The volume of the internal spoke cavity, and the vertical axis represents the sound pressure. The measurement is 5.
A 195/60R14 pneumatic radial tire was installed on a 1/2 JX14 wheel.

Further, it is advantageous to have three or more cavities; if there are two or less cavities, sufficient effects cannot be obtained during transfer, as shown in FIG. 5. FIG. 5 shows the relationship between the axle acceleration at the resonance frequency of the tire cavity and the number of spokes during transfer. At which time, the volume of the spoke cavity is 70 cf.
It is fl.

(Example) According to the structure shown in Fig. 1 and Fig. 3 (a), 51/
A 195/60R14 pneumatic radial tire is installed on a 2JX14 rim. Note that a cavity was provided in each spoke, and the volume of the cavity within each spoke was 100 cJ.

Further, the resonant frequency f of the cavity was 250 Hz.

FIG. 6 shows the results of a vehicle interior noise test conducted on this tire wheel and a tire wheel in which a pneumatic radial tire of the same size was assembled on a rim of the same size.

The vehicle interior noise test measured the sound in the driver's left ear while driving at a steady speed of 60 km/h on a road noise road. Also, the internal pressure of the tire is 1.9 kg/CTA.

From the figure, it can be seen that the peak that appears around 240.260 Hz in the comparative example does not appear in the example.

(Effects of the Invention) According to the present invention, the peak of road noise caused by the resonance of the air-filled chamber inside the tire, which cannot be countered especially for the vehicle body, can be suppressed with high durability without impairing the tire motion performance. It can be extinguished under sex.

[Brief explanation of the drawing]

Figures 1 and 2 are cross-sectional views of a tire wheel according to the present invention, Figures 3 (a) to (C) are perspective views of the wheel, and Figure 4 is the relationship between the spoke internal cavity volume and the internal tire resonance sound pressure. Figure 5 is a graph showing the relationship between the number of cavities in the spokes and axle acceleration, and Figure 6 is a graph showing the results of frequency analysis of vehicle interior noise tests. 1...Rubber tire 2...Tread 3...
Rim 4...Air filling chamber 5...Spokes 6...Cavity part 7...Communication path
8...Sound absorbing layer patent applicant: Bridgestone Co., Ltd. 3 tires p Li Shishine counterfeiter pressure (dβ)

Claims (1)

[Claims] 1. It consists of a hollow toroid-shaped rubber tire, a rim with a flange that suppresses the bead of the rubber tire, and spokes that connect the rim to a disk. A low-noise tire wheel with internal spokes.