JP2000233769A - Vehicular sound absorbing wheel cover - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance sound absorbing performance of a vehicular sound absorbing wheel cover by generating a phase difference between noise passing through interference chambers and noise entering all the way turning around a wheel cover, and making these interfere with each other. SOLUTION: A vehicular sound absorbing wheel cover has a main body part and a sound absorbing part, the main body part is fixed to a car body, and is formed of a rigid material for covering a part of a wheel. The sound absorbing part is fixed to an opposed surface with a wheel of the main body part or one end of the main body part, and is formed as a member having plural interference chambers 23 having opening both ends. These interference chambers 23 are a tubular passage having opening both ends, and generate a different in a wave length between the sound passed through these chambers and an unpassed sound when the sound incident from an opening part of one end comes out of an opening part of the other end. Thus, noise generated around the wheel is passed through the interference chambers 23 of a wheel house 23 to generate a phase difference between the noise and noise entering all the way turning a round a wheel house 20 to reduce the noise.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle sound absorbing wheel cover for absorbing tire / road noise in vehicles such as automobiles and trucks.

[0002]

2. Description of the Related Art In recent years, external noise generated by vehicles such as automobiles and trucks has become a serious problem in everyday life for residents in large cities and around highways along with air pollution caused by exhaust gas. As a noise source of such external noise, an engine (50
%), Exhaust system (20%), tires (15-20%), and the like.

[0003] Further, when the vehicle is running at high speed and steady, the engine speed is kept low, so that the relative proportion of the noise from the engine, which is outside the vehicle, is reduced, and the noise from the tire as a sound source has become remarkable. . Here, in general, the noise generated from around the tires when the vehicle is running at a high speed has a loud sound having a frequency around 800 to 2 kHz.

[0004] Regarding the reduction of the noise of the engine system, the noise is reduced mainly by employing a shielding structure such as an engine block cover, an engine cover, and a body side cover. In addition, measures to reduce the noise generated from the exhaust system are taken by mufflers. In vehicles such as trucks, the attachment of a body side cover was also effective in reducing noise.

In order to reduce the noise generated from the tire, the noise is reduced by changing the rigidity and the pattern shape of the tire. However, with regard to the reduction of noise generated from tires, from the viewpoint of safety such as running stability, wet performance, braking distance stability, etc., the rigidity and pattern shape were changed to significantly reduce noise. Could not be obtained.

[0006] In addition, since the tires are rotating when the vehicle is running, there is also a problem that it is not possible to cover the sound generated by attaching a cover like an engine or the like.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a vehicle sound absorbing wheel cover having high sound absorbing performance.

[0008]

In order to solve the above-mentioned problems, the present inventor has proposed a method of reducing a sound generated around a wheel by generating a phase difference in a sound generated around the wheel. It has been found that a method of reducing noise by interfering and canceling out a sound that does not have a phase difference with a sound that has no phase difference is effective, and the above problem can be solved by using a wheel cover using this noise reduction method. Was found.

That is, a sound absorbing wheel cover for a vehicle according to the present invention is fixed to a vehicle body and formed of a rigid material covering a part of the wheel, and fixed to a surface of the main body facing the wheel or to one end of the main body. And a sound absorbing portion having a plurality of interference chambers partitioned into a tubular shape with both ends opened. The sound absorbing wheel cover for a vehicle according to the present invention includes:
By having the interference chamber, a phase difference is generated between the sound passing through the interference chamber and the sound wrapping around the wheel cover, and the two sounds interfere with each other, thereby being generated around the wheel. Noise can be reduced.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A sound absorbing wheel cover for a vehicle according to the present invention has a main body and a sound absorbing part. Here, the wheel cover includes not only a wheel house cover of the vehicle but also a mudguard arranged behind the wheel. The main body is formed of a rigid material fixed to the vehicle body and covering a part of the wheel. That is, it is a member that maintains the rigidity of the wheel cover and attaches the wheel cover to the vehicle. The material of the main body may be any material such as resin and metal as long as it is a member having rigidity.

The sound absorbing portion is a member having a plurality of interference chambers which are fixed to a surface of the main body portion facing the wheel or one end of the main body portion and open at both ends. The sound absorbing portion is fixed to a surface of the main body facing the wheel or to one end of the main body. That is, not only the wheel house that covers a part of the wheel,
It can be used as a mudguard mounted on a wheel house.

The sound absorbing section has a plurality of interference chambers open at both ends. The interference chamber is a tubular passage whose both ends are open. When the sound incident from the opening at one end passes through the interference chamber and exits from the opening at the other end, the sound that does not pass through the interference chamber , A wavelength shift occurs. The occurrence of this shift reduces the perceived sound. The interference chamber is preferably partitioned into a tubular shape. Partitioning the interference chamber into a tubular shape can be easily formed because the internal shape of the interference chamber is not complicated. In addition, the tubular shape of the interference chamber is a state in which one end is opened on a surface facing the wheel and the other end is opened on a surface of the main body that does not face the wheel, and its cross-sectional shape is not particularly limited. , A circle, an ellipse, or a polygon such as a triangle or a square.

That is, since the sound absorbing wheel cover for a vehicle according to the present invention has the interference chamber in the sound absorbing portion, the noise can be reduced by causing the noise to interfere. The sound absorbing portion may be any member as long as it can define the interference chamber. That is, as long as the interference chamber can be partitioned, it can be formed of the same member as the main body. That is, the sound absorbing section having the interference chamber may be directly formed in the main body. Further, any material may be used as a material constituting the sound absorbing portion. That is, it can be formed of a material such as a metal and a resin.

When the sound absorbing portion and the main body are separate members, the joining of both may be performed by any joining method that can be used for joining the materials formed therewith. For example, adhesive bonding, welding, caulking,
Screwing and the like can be given. It is preferable that the sound absorbing section has a plurality of sound absorbing chambers, one end of which is open on the surface facing the wheel and the other end of which is closed. The sound absorbing chamber functions as a branch pipe type resonance chamber, and the sound generated from around the wheel is designed so that its length becomes a node at the resonance frequency at the resonance frequency, thereby reducing the sound pressure.

The sound absorbing chamber is preferably partitioned into a tubular shape. Dividing the sound absorbing chamber into a tubular shape can be easily formed because the internal shape of the sound absorbing chamber is not complicated. In addition, the tubular shape of the sound-absorbing chamber is a state in which it is opened on the surface facing the wheel and the other end is closed, and its cross-sectional shape is not particularly limited. And a polygonal shape such as a square.

The length of the sound absorbing chamber from the opening that opens to the surface facing the wheel to the other end is one of the wavelengths of the sound to be absorbed.
/ 4 is preferred. In general, a branch pipe type resonance chamber has an effect of effectively absorbing a sound of a specific frequency. In this resonance chamber, the frequency of sound that can be absorbed changes depending on the length from the opening of the resonance chamber to the other end.

Specifically, when the resonance chamber has a tubular shape with one end open and the other end closed, the length is four times the length from the opening with one end open to the other end. The sound having the wavelength having the wavelength can be efficiently absorbed. That is, the incident wave that has entered the inside of the resonance chamber through the opening passes through the resonance chamber, is reflected at the other end, and is radiated from the opening outside the resonance chamber as a reflected wave after passing through the resonance chamber again. here,
At the opening of the resonance chamber, the phase of the incident wave and the reflected wave is 18
When there is a phase difference of 0 degrees, the incident wave and the reflected wave cancel each other, and the amplitude becomes zero.

The phase difference of 180 degrees is 1 in terms of wavelength.
/ 2 wavelengths. In order for a phase difference of １ ／ wavelength to occur when an incident wave reciprocates from the opening to the other end, the distance between the opening and the other end needs to be ４ wavelength. Therefore, by using a tubular sound-absorbing chamber having a length of 1/4 of the wavelength of the sound of the frequency to be absorbed, the sound of that frequency can be absorbed.

The sound absorbing chamber preferably absorbs sound having a frequency of 200 to 5 kHz. For sound having a frequency of less than 200 Hz, the length of the sound absorbing chamber that absorbs sound having a frequency in this range becomes long, and it becomes difficult to attach the vehicle wheel cover to the vehicle. On the other hand, for a sound having a frequency exceeding 5 kHz, the length of the sound absorbing chamber is shortened, and the sound absorbing chamber does not function as a branch pipe type resonance chamber. In addition, this 200-5
The length of the sound absorbing chamber corresponding to the frequency range of kHz is 425.
１７17 mm. A more preferred frequency range is 800
２2 kHz. That is, in general, the noise generated from around the tires when the vehicle is running at a high speed is 800 to 2 kHz.
Sound at frequencies near z is loud, and it is preferable to absorb sounds at frequencies in this range. The length of the sound absorbing chamber corresponding to the frequency range of 800 to 2 kHz is 106 to 42.5.
mm.

It is preferable that the sound absorbing section is divided into a plurality of sound absorbing chambers for absorbing sounds of different wavelengths. That is,
By partitioning a plurality of sound absorbing chambers having different lengths, sounds having different wavelengths can be absorbed. It is preferable that an interference chamber is opened between the main body and the sound absorbing part and has an interference passage that is open to the outside. That is, it is possible to lengthen the path for the interference and to adjust the location and the direction in which the noise passing through the interference chamber is emitted. In other words, the noise that has passed through the interference chamber is emitted toward the ground or on the side of the oncoming lane, so that the influence of noise on the surroundings can be suppressed. This interference passage is preferably formed by disposing an interference plate at a position outside the opening of the interference chamber.

The vehicle equipped with the vehicle sound absorbing wheel cover of the present invention can be applied not only to vehicles such as ordinary passenger cars but also to vehicles such as trucks.

[0022]

The present invention will be described below with reference to examples. (Example 1) Example 1 is a wheel house used for a rear wheel of a truck. Wheel house 20 of the first embodiment
Is shown in FIG. FIG. 2 shows a view when the wheel house 20 is mounted on a truck.

The wheel house 20 according to the first embodiment is located above the wheel and is formed in a substantially rectangular bulk so as to cover a part of the wheel. further,
In the wheel house 20 according to the first embodiment, a sound absorbing chamber 21 and an interference chamber 23 are defined. Interference room 23 and sound absorption room 2
1 is partitioned at the peripheral edge of the end of the wheel house 20. Here, the periphery of the end of the wheel house 20 is
Since the thickness is formed to be large, the space of the sound absorbing room 21 and the interference room 23 is maintained. The interference room 23 and the sound absorbing room 21 are partitioned such that the interference room 23 is located on the end side of the wheel house 20 and the sound absorbing room 21 is located inside the wheel house 20.

In the wheel house of the first embodiment, the noise generated around the wheel is passed through the interference chamber 23 of the wheel house, so that the noise passing around the wheel house and the noise passing through the interference chamber 23 are interposed. A phase difference is generated to reduce noise. In addition, the noise generated around the wheel is reduced by the sound absorbing chamber 21 acting as a branch pipe type resonance chamber.

(Embodiment 2) The embodiment 2 is a wheel house similar to the wheel house 20 of the embodiment 1 except that an interference plate 25 is provided. FIG. 3 shows a cross section of the wheel house 22 of the second embodiment. Example 2 wheel house 22
Has an interference plate 25 arranged in the interference chamber 27 of the wheel house so as to face the opening in the extension direction of the opening not facing the wheel. This interference plate 25 is formed integrally with the wheel house 22,
An interference passage 26 is defined between the wheel house 22 and the wheel house 22. The interference passage 26 is partitioned so as to have an opening. This opening is provided at the end of the wheel house 22.

In the wheel house 22 according to the second embodiment, the interference path that causes a phase difference can be lengthened by the interference path 26. Further, by adjusting the position of the opening of the interference passage 26, the direction of discharging the noise having a phase difference through the interference passage can be adjusted, and the noise can be reduced in any direction. (Embodiment 3) Embodiment 3 is a mudguard for a passenger car. The mudguard of the third embodiment is a mudguard attached to a wheel house and a joint end of a bottom surface of a vehicle. FIG. 4 shows the mudguard 3 of the third embodiment. FIG. 5 shows a view when the mudguard 3 of the third embodiment is mounted on the passenger car 15.

The mudguard 3 according to the third embodiment has a sound absorbing chamber 31, an interference chamber 33, and an interference passage 36. When the sound absorbing chamber 31 and the interference chamber 33 are mounted on a vehicle, the mudguard 3 is opened on a facing surface facing the wheel. So that they are integrally formed. In addition, a sound discharge port 35 is opened on a wall surface defining the interference passage 36. One end of the sound absorbing chamber 31 is opened on a surface facing the wheel, and extends obliquely upward from this opening to form a mudguard 3.
Is partitioned into a closed tube at the other end. The cross-sectional shape of the tubular sound absorbing chamber 31 was a quadrangle.

Similarly to the sound absorbing chamber 31, the interference chamber 33 extends obliquely upward from the opening formed on the opposing surface to the inside of the mudguard 3, and is divided into a tubular shape having the other end opened inside the mudguard 3. ing. In addition, the tubular interference chamber 33
Is formed so as to bend in the rearward direction of the vehicle inside the mudguard 3. The interference passage 36 is formed inside the mudguard 3, and has an opening at the other end of the interference chamber 33 and a sound outlet 35. Here, the sound outlet 35 is
It opens on the extension of the opening on the other end side of the interference chamber 33.

In the mudguard of the third embodiment, the noise generated around the wheel is passed through the interference chamber 33, so that a phase difference is generated between the noise that has passed around the mudguard and the noise that has passed through the interference chamber 33. Noise is reduced by causing two sounds having the phase difference to interfere with each other. Further, the noise generated around the wheel is reduced by the sound absorbing chamber 31 acting as a branch pipe type resonance chamber.

Further, the mudguard of the third embodiment is provided with
Thereby, the path for generating the phase difference can be lengthened. In addition, it can be mounted on an actual vehicle by using a wall surface that divides the interference passage 36 constituting the mudguard.

[0031]

The sound absorbing wheel cover for a vehicle according to the present invention is
By having the interference chamber, of the noise generated around the wheel, the noise passing through the interference chamber and the noise wrapping around the wheel cover generate a phase difference, and interfere with each other, so that the noise around the wheel is generated. This is to reduce the noise generated in.

[Brief description of the drawings]

FIG. 1 is a sectional view of a wheel house according to a first embodiment.

FIG. 2 is a diagram showing a truck and a wheel house.

FIG. 3 is a sectional view of a wheel house according to a second embodiment.

FIG. 4 is a cross-sectional view of a mudguard according to a third embodiment.

FIG. 5 is a view showing a car and a mudguard.

[Explanation of symbols]

11 ... Truck 15 ... Passenger car 20, 22 ... Wheel house 21, 24 ... Resonance room 23, 27 ... Interference room 25 ... Interference plate 26 ...
Interference passage 3 Mudguard 31 Sound absorbing room 33
Interference chamber 35 ... Sound discharge hole 36 ... Interference passage

Claims (5)

[Claims] 1. A body fixed to a vehicle body and formed of a rigid material covering a part of a wheel, and a plurality of bodies fixed to a surface of the body facing the wheel or one end of the body and having both ends opened. A sound absorbing wheel cover for a vehicle, comprising: 2. The sound absorbing wheel cover for a vehicle according to claim 1, wherein the sound absorbing portion has a plurality of sound absorbing chambers having one end opened on the surface facing the wheel and the other end closed. 3. The sound absorbing wheel cover for a vehicle according to claim 2, wherein the length from the opening to the other end of the sound absorbing chamber is １ ／ of the wavelength of the sound to be absorbed. 4. The sound absorbing wheel cover for a vehicle according to claim 2, wherein the sound absorbing section is divided into a plurality of sound absorbing chambers for absorbing sounds of different wavelengths. 5. The interference chamber is open between the main body and the sound absorbing section, and has an interference passage open to the outside.
4. The vehicle sound absorbing wheel cover according to 4.