JP2559477B2 - Exhaust silencer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an exhaust silencer for reducing exhaust noise of an engine mounted on a vehicle.

2. Description of the Related Art As an exhaust muffler of this type, for example, the actual Kaisho Sho 58-72
Some are disclosed in Japanese Patent No. 410.

That is, in such an exhaust muffler, the inside of the muffler body formed in the closed space is a plurality of compartments, and the muffler body is provided with an exhaust conduit penetrating the compartments in a meandering manner. Each bent portion (U-turn portion) of the exhaust pipe that meanders is formed of a perforated pipe, and the high frequency component of the exhaust sound is absorbed by the perforated pipe portion.

In addition, Japanese Utility Model Publication No. 58-72410, Japanese Utility Model Publication No. 62-3910,
Like the invention described in Japanese Utility Model Publication No. 61-37415,
One of the plurality of partition chambers is used as an expansion chamber, and the other partition chambers are filled with a sound absorber, and an exhaust pipe is arranged so as to meander through the plurality of partition chambers in the arrangement direction, or the exhaust gas is exhausted. There is also provided one in which a portion of the conduit on the wake side where no hole is formed is lengthened to reduce low-frequency exhaust noise.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the conventional exhaust silencer disclosed in Japanese Utility Model Laid-Open No. 58-7240, each bent portion of the exhaust conduit is formed by a perforated pipe, and the perforated pipe portion is formed. Therefore, although exhaust noise can be effectively reduced by discharging exhaust noise into the above-mentioned compartment, the exhaust conduit has a large number of porous portions, so that low-frequency components of the exhaust noise can be reduced. There is a problem that it is difficult to efficiently reduce the exhaust gas by itself.

Further, in the conventional example disclosed in Japanese Utility Model Laid-Open No. 58-72410, although there is an effect of reducing exhaust noise of low, middle and high frequencies, it is possible to reduce exhaust noise of all frequencies of low to high frequencies. Not only the effect cannot be obtained, but also more efficient exhaust noise reduction effect cannot be obtained.

Therefore, in view of the above conventional problems, it is an object of the present invention to provide an exhaust silencer capable of efficiently reducing high-frequency components of exhaust noise and also reducing low-frequency components thereof.

Means for Solving the Problems In order to achieve the above object, the present invention provides (1) a muffler main body formed in a closed space, a plurality of compartments formed in the muffler main body, and the inside of the muffler main body. And an exhaust gas silencer that is arranged in a plurality of partition chambers and meanders through the plurality of partition chambers in the arrangement direction, and at least one of the plurality of partition chambers is an expansion chamber. The sound absorbing member is filled with a sound absorbing body covered with a metal sheet in a compartment other than the expansion chamber, and among a plurality of meandering bent portions of the exhaust conduit, the bent portion existing on the discharge side is located behind the bent portion. The exhaust conduit on the flow side is formed by a tube without holes, and the exhaust conduit on the upstream side of the bent portion is formed by a multi-perforated tube, and a small partition plate is provided between the expansion chamber and the partition chamber. The feature is that many holes are formed.

In the exhaust silencer of the present invention having the above configuration,
The engine exhaust sound introduced into the exhaust pipe is first expanded in the expansion chamber to reduce its sound pressure to reduce middle and low frequency components, and the bent portion formed by the perforated pipe of the exhaust pipe. The high frequency component is reduced by the sound absorber.

Further, since the exhaust conduit on the wake side is formed by the pipe without holes, air column resonance is easily generated in the holeless portion, and the air column resonance further reduces the low frequency component.

Further, since the sound absorbing material is covered with the metal sheet in the sound absorbing body, it is possible to prevent the sound absorbing body from scattering to the outside when the sound absorbing body is filled in the compartment.

Furthermore, since a large number of small holes are formed in the partition plate between the expansion chamber and the partition chamber, both the expansion function and the sound absorption function are exerted by the expansion chamber, resulting in a more efficient exhaust noise reduction effect. To be

Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

That is, FIGS. 1 and 2 show one embodiment of the exhaust noise suppressor of the present invention. In FIG. 1, 10 is a muffler main body, and the muffler main body 10 is a tubular body 10a having an elliptical cross section. A closed space is formed by the end plates 10b and 10c that hermetically close the openings at both ends of the tubular body 10a.

The inside of the muffler body 10 is divided by the partition plates 12 and 12a from the left side in the drawing toward the central axis direction of the cylindrical body 10a to form the first, second and third compartments 1
4,14a, 14b, and each of these compartments 14,14a, 14b
Of these, the first partition chamber 14 on the left side (exhaust gas introduction side) in the figure is used as an expansion chamber.

In addition, the first partition chamber 14 and the second partition chamber that have become the expansion chambers.
As shown in FIG. 6, a large number of small holes 32 are formed in the partition plate 12 provided between the partition plate 14a and the partition plate 14a.

Then, in the muffler body 10, each of the compartments 14, 1
An exhaust pipe 16 is provided so as to penetrate the 4a and 14b in the arrangement direction (horizontal direction in the drawing), and the exhaust pipe 16 is supported by the penetrating portions of the partition plates 12 and 12a.

The exhaust pipe 16 has a structure in which engine exhaust is introduced from the left side of the drawing and is discharged from the right side of the drawing. Two U are provided between the introduction side and the discharge side of these exhausts.
Character-shaped first and second bent portions 16a and 16b are formed.

Then, the first bent portion 16a located on the upstream side of the exhaust flow
Is bypassed in the third partition chamber 14b, and the second bent portion 16b located on the downstream side is bypassed in the expansion chamber 14.

The first bent portion 16a is formed of a perforated pipe 18 including a pipe portion continuous with the first bent portion 16a.

That is, as the section where the perforated pipe 18 is formed, the expansion chamber 14 is formed in the front flow direction of the first bent portion 16a, and the second partition chamber 14a is formed in the back flow direction. It

On the other hand, the second bent portion 16b is formed as a non-perforated pipe 20 including a pipe portion which is continuous on the downstream side of the second bent portion 16b.

The sound absorbing body 22 is filled in each of the second and third compartments 14a and 14b of the muffler body 10 excluding the expansion chamber 14.

As shown in FIG. 2, the sound absorbing body 22 is formed as a globular body by wrapping the sound absorbing material 22a in a mesh metal sheet 22b, and the sound absorbing body 22 thus constructed has the above-mentioned structure.
The second and third compartments 14a and 14b are filled innumerably.

In the exhaust silencer of the present embodiment having the above configuration, the exhaust gas discharged from the engine (not shown) is the muffler body 10
The exhaust sound introduced into the exhaust conduit 16 inside the exhaust pipe 16 and introduced into the exhaust conduit 16 together with the exhaust gas is first transmitted from the perforated pipe 18 of the exhaust introduction portion (expansion chamber 14 portion) of the exhaust conduit 16 to the expansion chamber 14
The sound pressure is reduced by being discharged into the inside of the exhaust sound,
Low frequency components are reduced.

Then, the exhaust sound whose middle and low frequency components have been reduced is connected to the first bent portion 16a and the front and rear flow sides thereof while passing through the first bent portion 16a of the exhaust conduit 16. The high-frequency component is reduced by the perforated pipe 18 forming the pipe, and the high-frequency component is discharged from the perforated pipe 18 into the second and third compartments 14a, 14b, and the high-frequency component is also absorbed by the sound absorber 22. .

By the way, in this embodiment, since the pipe 20 without holes is formed on the wake side from the second bent portion 16b, the pipe without holes 20
The air column resonance is easily generated by 20, and the exhaust noise of the low frequency component can be further reduced by utilizing the air column resonance.

Therefore, in the present embodiment, by the perforated pipe 18 provided in the exhaust conduit 16 and the sound absorbing body 22 in the muffler body 10,
The exhaust noise of high frequency components is effectively reduced, and the low frequency components of exhaust noise are effectively reduced by the air column resonance of the holeless pipe 20 provided in the expansion chamber 14 and the exhaust conduit 16, and the reduction effect. Is significantly improved.

In the present embodiment, the muffler body 10 has an expansion chamber 14
The second and third compartments 14a and 14b are divided into the second and third compartments 14a and 14b, but the second and third compartments 14a and 14b filled with the sound absorbing body 22 may be configured as one chamber. Alternatively, it may be configured as three or more chambers if necessary.

Further, the expansion chamber 14 has at least one inside the muffler body 10.
It must be provided as two separate rooms.

FIG. 3 is a characteristic diagram showing the sound pressure level of the exhaust sound with respect to the engine speed. In the characteristic A of the present embodiment, as compared with the characteristic B of the conventional silencer, the middle and low frequencies related to the engine speed. It was confirmed that the components were significantly reduced.

By the way, in the present embodiment, when the sound absorbing body 22 is filled in the second and third compartments 14a, 14b of the muffler main body 10,
Since the sound absorbing member 22a is covered with the metal sheet 22b on the outside of the sound absorbing member 22, the sound absorbing members 22a do not come into contact with each other and the filling property is not deteriorated. Instead, the sound absorbing body 22 can be filled in every corner, and the sound absorbing effect of the high frequency component is improved accordingly.

Further, by covering the sound absorbing material 22a with the metal sheet 22b in this manner, the sound absorbing material 22a is prevented from scattering outward when the sound absorbing body 22 is filled.

Although the sound absorbing body 22 is disclosed as being formed in a spherical shape, it may be formed in a cubic shape as shown in FIG. 4, or a porous metal is formed in a spherical shape as shown in FIG. By doing so, the sound absorber 30 may be configured.

Further, in this embodiment, since a large number of small holes 32 are formed in the partition plate 12 provided between the expansion chamber 14 and the second partition chamber 14a, the expansion chamber 14 exhibits both the expansion function and the sound absorbing function. Can be made.

EFFECTS OF THE INVENTION As described above, in the exhaust silencer of the present invention, at least one expansion chamber is provided in the muffler main body, the sound absorbing body is filled in the partition chamber other than the expansion chamber, and the exhaust conduit Of a plurality of meandering bent parts, the exhaust conduit on the downstream side of the bent part existing on the discharge side is formed by a tube without holes,
Moreover, since the exhaust conduit on the upstream side of the bent portion is formed of a perforated pipe, the engine exhaust sound introduced into the exhaust conduit has low and middle frequency components reduced in the expansion chamber, and the exhaust conduit The bent portion formed by the perforated tube and the sound absorbing body reduce the high frequency component, and further, the air column resonance of the non-perforated tube on the downstream side enables different reduction of the low frequency component.

Therefore, according to the present invention, it is possible to significantly reduce the high frequency component of the exhaust sound and significantly improve the reduction effect of the low frequency component of the exhaust sound. Therefore, it is possible to achieve a significant reduction of the exhaust noise. Produce the effect.

Further, in the sound absorbing body, since each of the sound absorbing materials is covered with the metal sheet, the sound absorbing bodies are prevented from scattering when the sound absorbing bodies are filled in the partition chamber.

Furthermore, on the partition plate that separates the expansion chamber and the partition chamber,
Since a large number of small holes are formed, the expansion chamber exerts two functions of an expansion function and a sound absorption function, and the effect of reducing exhaust noise is further improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an essential part of an embodiment of the present invention, FIG. 2 is a partial sectional view showing an embodiment of a sound absorber used in the present invention, and FIG. 3 shows an effect region of the present invention. Characteristic diagram of sound pressure level, FIGS. 4 and 5 are configuration diagrams showing other embodiments of the sound absorbing body used in the present invention, and FIG. 6 is I-I of FIG.
It is a line sectional view. 10 …… Muffler body, 14 …… First partition room (expansion chamber), 12…
… Differential plates, 14a, 14b …… Different chambers, 16 …… Exhaust pipes, 16a…
… First bent part, 16b …… Second bent part, 18 …… Perforated tube, 20 …… Pipeless tube, 22,30 …… Sound absorber, 22a …… Sound absorbing material, 22b …… Metal sheet.

Claims (1)

(57) [Claims] 1. A muffler body formed in a closed space, a plurality of compartments formed in the muffler body, and arranged in the muffler body, and the plurality of compartments meander in the arrangement direction. In the exhaust noise suppressor having an exhaust pipe penetrating therethrough, at least one of the plurality of partition chambers is an expansion chamber, and the partition chambers other than the expansion chamber are covered with a sound absorbing material with a metal sheet. Of the plurality of meandering bent parts of the exhaust conduit, the exhaust conduit on the downstream side of the bent part existing on the discharge side is formed of a holeless tube, and An exhaust silencer, characterized in that the exhaust conduit on the upstream side of the bent portion is formed of a perforated pipe, and that a large number of small holes are formed in the partition plate between the expansion chamber and the partition chamber.