JP2001140628A - Rotary fin type silencer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an arranging space, improve durability, and reduce costs, in a silencer for eliminating noise by utilizing reflection of sound wave and an interference action. SOLUTION: A noise eliminating cover 2 is disposed around an exhaust pipe 1. A noise eliminating space 4 in which a noise eliminating material 3 is filled is disposed in the noise eliminating cover 2. A noise eliminating fin 5 which is rotated by exhaust pressure in the exhaust pipe 1 is mounted in the noise eliminating cover 2. Exhaust noise is reflected around the exhaust pipe 1 through a rotating blade 5A of the noise eliminating fin 5. A part of reflecting noise is eliminated in the noise eliminating space 4, and a part of the reflecting noise is eliminated by interfering with exhaust noise.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary fin type muffler mounted on an internal combustion engine of a vehicle and muffles exhaust sound by utilizing the reflection and interference of sound waves.

[0002]

2. Description of the Related Art A muffler mounted on an internal combustion engine to muffle exhaust sound is provided with an expansion chamber for expanding exhaust gas, and a method for muffling the exhaust gas in the process of flowing the exhaust gas, and a method for reducing the noise around the exhaust pipe. There is a method of arranging a sound absorbing material. Each of these noise reduction effects is proportional to the volume of the space in which the expansion chamber and the sound absorbing material are provided.

[0003] On the other hand, Japanese Patent Laid-Open No. H08-163191 discloses a muffler that outputs a sound wave having a phase opposite to that of the exhaust sound from a speaker in response to the exhaust sound, and cancels the sound by interference between the exhaust sound and the sound wave having the opposite phase.
It is described in Japanese Patent Application Laid-Open No. 5-288032 and Japanese Patent Application Laid-Open No. 7-281677. This type of muffler is a device provided with a speaker and a pressure sensor in the vicinity of an exhaust port of an exhaust pipe, and a controller for outputting sound waves from the speaker in accordance with a signal detected by the pressure sensor.

[0004]

In the conventional method of disposing the expansion chamber and the sound absorbing material, the noise reduction effect is proportional to the volume of the space in which the expansion chamber and the sound absorbing material are provided. Space was required.

On the other hand, in a device that outputs a sound wave having a phase opposite to that of the exhaust sound and cancels the sound by interference, it is necessary to provide a speaker or a pressure sensor in the vicinity of the exhaust port. there were. In particular, since high-temperature exhaust gas is exhausted from the exhaust port, the speaker and the pressure sensor are exposed to high temperature and are easily damaged. Moreover, since it is necessary to provide a controller that outputs a sound wave of an opposite phase from the speaker based on the signal of the pressure sensor, the manufacturing cost of the entire silencer becomes higher than the above-described method using the expansion chamber and the sound absorbing material. There are inconveniences.

Therefore, in order to solve the above-mentioned problems, the present invention has developed a completely new silencer which silences by utilizing the reflection and interference of sound waves, and is installed in comparison with a silencer using an expansion chamber or a sound absorbing material. The purpose is to provide a rotating fin type silencer that requires less space, is more durable than a device that outputs sound waves of opposite phase and silences by interference, and can be manufactured at low cost. is there.

[0007]

A first means of the present invention created to achieve the above object is a muffler mounted on an exhaust pipe 1 connected to an internal combustion engine. A muffling cover 2 is provided, a muffling space 4 filled with a muffling material 3 is provided inside the muffling cover 2, and a muffling fin 5 that rotates by the exhaust pressure in the exhaust pipe 1 is attached to the exhaust pipe 1 in the muffling cover 2. Then, the exhaust sound is reflected around the exhaust pipe 1 through the rotating blades 5A of the sound deadening fins 5, and a part of the reflected sound is silenced in the sound deadening space 4, and a part of the reflected sound interferes with the exhaust sound. To mute the sound.

The second means is to form a pair of silencing spaces 4 on the opposite outer side surfaces of the exhaust pipe 1 with the exhaust pipe 1 at the center, and to accommodate the rotating silencing fin 5 in one of the silencing spaces 4. A fin housing 6 is provided, and a sound absorbing plate 7 having a large number of sound absorbing holes 7A is interposed between the inside of the exhaust pipe 1 and the sound deadening material 3 in each sound deadening space 4.

The sound absorbing fin 5 of the third means is provided with a plurality of blades 5A having a length substantially equal to the diameter of the exhaust pipe 1. The sound absorbing fin 5 is provided by increasing or decreasing the interval between the fin housing 6 and the sound absorbing fin 5. This is for adjusting the rotation speed.

The silencing fin 5 of the fourth means has a rotation adjusting motor for adjusting the number of revolutions of the silencing fin 5.

Fifth means is a muffler mounted on an exhaust pipe 1 connected to an internal combustion engine. A muffler cover 2 is provided around the exhaust pipe 1, and a muffling fin 5 that rotates by the exhaust pressure in the exhaust pipe 1 is provided. Is attached to the exhaust pipe 1 in the muffling cover 2 and the muffling fins 5 are attached.
It is a means for solving the problem that the exhaust sound is reflected to the periphery of the exhaust pipe 1 via the rotating blades 5A of the above, and a part of the reflected sound interferes with the exhaust sound to mute the sound.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings.

Reference numeral 1 shown in the figure is an exhaust pipe connected to the internal combustion engine. According to the present invention, a muffler cover 2 is provided around the exhaust pipe 1 so as to be attached to the exhaust pipe 1 in the middle or at the end thereof. Further, a silencing material 3 is provided inside the silencing cover 2.
Is provided (see FIG. 1).
The silencing space 4 is formed as a pair on the outer side surface of the exhaust pipe 1 facing the exhaust pipe 1 with the exhaust pipe 1 at the center. Also, between the inside of the exhaust pipe 1 and the muffling material 3 in each muffling space 4,
The sound absorbing plate 7 having many sound absorbing holes 7A is interposed.

Reference numeral 5 denotes a sound deadening fin which is rotated by the exhaust pressure in the exhaust pipe 1.
It is attached to the exhaust pipe 1 inside. The illustrated sound deadening fins 5
It is housed in one muffling space 4 of the muffling cover 2. The sound deadening fins 5 reflect the exhaust sound to the periphery of the exhaust pipe 1 via the rotating blades 5A. In order to enhance the sound deadening effect at the time of reflection, a concave portion may be formed on the reflection surface of the blades 5A. . Then, a part of the reflected sound by the blade 5A is silenced in the silencing space 4, and a part of the reflected sound is made to interfere with the exhaust sound to be silenced (see FIG. 5).
The illustrated blade 5A shows an example in which three blades 5A having substantially the same length as the diameter of the exhaust pipe 1 are provided, but the number of blades 5A can be set arbitrarily.

Further, since the fin housing portion 6 for housing the sound deadening fins 5 has an inner diameter which is about twice as large as the diameter of the exhaust pipe 1, there is no possibility that the exhaust efficiency is hindered. Further, by adjusting the increase / decrease of the interval between the fin housing portion 6 and the sound deadening fin 5, the rotation speed of the sound deadening fin 5 can be adjusted. Also, although not shown, the sound deadening fins 5
In addition, by providing a rotation adjusting motor for adjusting the number of rotations of the silencing fin 5, the number of rotations of the silencing fin 5 can be adjusted to an arbitrary number of rotations at any time.

According to the silencing fins 5, the exhaust noise of the exhaust pipe 1 is reflected by the respective silencing spaces 4 and the exhaust pipe 1 depending on the angle of the blades 5 A in the exhaust pipe 1. That is, FIG. 1 shows an example in which the sound is reflected by the sound deadening space 4 opposite to the sound deadening space 4 in which the sound deadening fins 5 are provided. In this example, the reflected sound is effectively eliminated by a large amount of the silencing material 3.

FIG. 4 shows an example in which the sound is reflected by the sound deadening space 4 provided with the sound deadening fins 5. In this example, the reflected sound is eliminated by the silencing material 3 and the rotating silencing fin 5 is rotated.
The reflected sound is also eliminated by the agitating action of the exhaust gas flowing through the fin housing 6 and the like, so that a synergistic effect can be obtained in the noise reduction effect.

FIG. 5 shows an example in which the exhaust sound in the exhaust pipe 1 is reflected toward the original exhaust pipe 1. In this example, the highest noise reduction effect is obtained by the interference between the exhaust sound and the reflected sound. The exhaust gas is exhausted to the outside of the exhaust pipe 1 by rotating the sound deadening fins 5, so that the exhaust gas does not lower the exhaust efficiency, but reflects only the sound wave of the exhaust sound. In addition, since the noise canceling effect is obtained in each of the reflection directions of the reflected sound, the exhaust sound finally discharged from the exhaust pipe 1 into the atmosphere is a crisp low tone accompanied by a pulse.

When the silencing space 4 filled with the silencing material 3 is not provided in the silencing cover 2, a more crisp deep bass accompanied by a strong pulse can be produced. At this time, by providing various concave portions on the reflection surface of the blade 5A, it is possible to change the intensity and tone of the exhaust sound.

[0020]

According to the present invention, the original object is achieved by the above-mentioned structure.

That is, a muffling cover 2 is provided around the exhaust pipe 1.
A silencing space 4 filled with a silencing material 3 is provided inside the silencing cover 2, and a silencing fin 5 that rotates by the exhaust pressure in the exhaust pipe 1 is attached to the exhaust pipe 1 in the silencing cover 2. Exhaust sound is reflected around the exhaust pipe 1 through the rotating blades 5A of the fins 5, a part of the reflected sound is silenced in the silencing space 4, and a part of the reflected sound interferes with the exhaust sound. By doing so, we succeeded in developing a completely new silencer that silences using the reflection and interference of sound waves. As a result, it has become possible to reduce the installation space as compared with the conventional muffler using an expansion chamber or a sound absorbing material.

Further, a pair of the silencing spaces 4 are formed on the opposing outer surfaces of the exhaust pipe 1 with the exhaust pipe 1 at the center, and a fin housing portion for accommodating the rotating silencing fin 5 in one of the silencing spaces 4. 6, and a sound absorbing plate 7 having a large number of sound absorbing holes 7 </ b> A interposed between the inside of the exhaust pipe 1 and the sound absorbing material 3 in each sound absorbing space 4, so that the sound reflected by the sound absorbing fins 5 can be reduced. The sound could be effectively silenced in the space 4.

Further, since the noise reduction fins 5 are provided with a plurality of blades 5A having a length substantially equal to the diameter of the exhaust pipe 1, the noise reduction effect due to the interference effect obtained by reflecting the exhaust pipe 1 in the direction of the internal combustion engine. Can be increased. Further, by increasing or decreasing the distance between the fin housing section 6 and the sound absorbing fin 5,
By adjusting the rotation speed of the internal combustion engine, noise can be suppressed corresponding to the characteristics of the internal combustion engine.

Also, by providing a rotation adjusting motor for adjusting the number of rotations of the silencing fin 5, the number of rotations of the silencing fin 5 can be adjusted to an arbitrary number of rotations at any time. The user can adjust the intensity and pitch of the exhaust sound.

Further, a muffling cover 2 is provided around the exhaust pipe 1, and a muffling fin 5 which rotates by the exhaust pressure in the muffler 1 is attached to the muffler 2 inside the muffler cover 2. When the silencing space 4 filled with the material 3 is not provided, a crisp deep bass accompanied by a stronger pulse can be produced.

As described above, according to the present invention, a completely new silencer that silences by utilizing the reflection and interference of sound waves has been successfully developed, and requires a small installation space, and is excellent in durability. Various industrially useful effects such as a low production cost can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention.

FIG. 2 is a plan sectional view showing one embodiment of the present invention.

FIG. 3 is a side sectional view showing one embodiment of the present invention.

FIG. 4 is a cross-sectional view of a main part showing one embodiment of a reflection state by the sound deadening fin of the present invention.

FIG. 5 is a cross-sectional view of a principal part showing another embodiment of the reflection state by the sound deadening fin of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exhaust pipe 2 Sound-absorbing cover 3 Sound-absorbing material 4 Sound-absorbing space 5 Sound-absorbing fin 5A Blade 6 Fin storage section 7 Sound-absorbing plate 7A Sound-absorbing hole

Claims (5)

[Claims] 1. A muffler mounted on an exhaust pipe connected to an internal combustion engine, wherein a muffling cover is provided around the exhaust pipe, and a muffling space filled with a muffling material is provided inside the muffler cover. A noise reduction fin that rotates with the exhaust pressure inside the pipe is attached to the exhaust pipe inside the noise reduction cover, and the exhaust sound is reflected around the exhaust pipe through the rotating blades of the noise reduction fin, and part of the reflected sound is reduced in the noise reduction space. A rotating fin type silencer, which silences, and at the same time, silences part of the reflected sound by interfering with exhaust sound. 2. A fin housing portion, which is formed in a pair on the outer side surface of the exhaust pipe facing the exhaust pipe with the exhaust pipe at the center, and has a fin housing portion for housing the rotating noise fin in one of the noise reduction spaces, 2. The rotary fin type silencer according to claim 1, wherein a sound absorbing plate having a large number of sound absorbing holes is interposed between the inside of the pipe and the sound absorbing material in each sound absorbing space. 3. The sound deadening fin is provided with a plurality of blades having a length substantially the same as the diameter of an exhaust pipe, and the number of rotations of the sound deadening fin is adjusted by increasing or decreasing the interval between the fin housing portion and the sound deadening fin. 3. The rotary fin silencer according to 1 or 2. 4. The sound deadening fin includes a rotation adjusting motor for adjusting a rotation speed of the sound deadening fin.
The rotary fin silencer according to any of the above. 5. A muffler attached to an exhaust pipe connected to an internal combustion engine, wherein a muffling cover is provided around the exhaust pipe, and a muffling fin that rotates by exhaust pressure in the exhaust pipe is attached to the exhaust pipe in the muffler cover. A rotating fin type silencer that is mounted and reflects exhaust sound to the surroundings of an exhaust pipe through rotating blades of the sound deadening fin, and part of the reflected sound interferes with the exhaust sound to muffle the sound.