JPH08144735A - Noise absorbing muffler - Google Patents

Abstract

PURPOSE: To improve a noise absorbing muffler installed in an exhaust system of an automobile, which muffler eliminates noises particularly in medium/high frequency areas, that is, prevent thermal deterioration of a glass wool member and improve noise eliminating effect of a noise absorbing muffler. CONSTITUTION: A porous exhaust pipe 5 is provided. A cylindrical body 2 is arranged around the porous exhaust pipe 5, for forming a muffler chamber 6 in respect to the porous exhaust pipe 5. A porous cylindrical partition pipe 7 is arranged inside the muffler chamber 6 for dividing the muffler chamber 6 in a diameter direction to form an inner side muffler area 8 and an outer side muffler area 9. A metal wool layer 10 is arranged in the inner side muffler area 8 and supported onto an outer peripheral surface 5B of the porous exhaust pipe 5. A glass wool member 11 is charged in the outer side muffler area 9.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound absorbing silencer mounted on an exhaust system of an automobile, and more particularly, to an improvement of the sound absorbing silencer for removing noise in a medium and high frequency range.

2. Description of the Related Art Conventionally, as a muffler for removing mid-high frequency components of exhaust noise, for example, an actual Kaihei 2-1291 is used.
The one shown in Japanese Patent Publication No. 2 is known as shown in FIGS. In the figure, reference numeral 100 is a muffler, which has an exhaust lead-out pipe 101, and a sound-absorbing muffler that extends over the first extension chamber 103A and the second extension chamber 103B at the tip end side of the exhaust lead-out pipe 101. The container 104 is attached. The sound absorbing silencer 104 has a tubular body 102, and the reduced diameter portions 102A and 102B are formed at both ends of the tubular body 102. The tip of the exhaust gas outlet pipe 101 is provided with a porous exhaust pipe 105.
The porous exhaust pipe 105 penetrates the reduced diameter portions 102A and 102B of the cylindrical body 102, and the porous exhaust pipe 5 is formed with a plurality of small holes 105A. In this way, the tubular body 102 surrounds the porous exhaust pipe 105, and the tubular body 102
A muffling chamber 106 is formed between the exhaust pipe 105 and the porous exhaust pipe 105. A perforated cylindrical partition pipe 107 is arranged in the muffler chamber 106, and the perforated cylindrical partition pipe 107 has a plurality of small holes 107A, and the muffler chamber 106 is radially divided to form an inner space region 108.
And an outer space region 109 is formed. Outer space area 10
A glass wool layer 110 is contained in the container 9. The glass wool layer 110 is made of a fibrous material containing silicon oxide as a main component, and has a cotton shape.

However, in the conventional sound absorbing silencer, the heat of the exhaust gas in the perforated exhaust pipe 105 is transferred to the glass wool layer 110 via the inner space region 108, and the glass wool layer 110. The temperature of the exhaust gas in becomes high. Since the thermal conductivity of the glass wool layer 110 is smaller than that of metal, the heat is generated by the glass wool layer 110.
Of the glass wool layer 110 is melted,
The glass wool layer 110 is deteriorated by heat, and the original sound absorbing function of the glass wool layer 110 is deteriorated. Also,
Since the glass wool layer 110 is housed outside the inner space area 108, it is possible to prevent scattering by the exhaust gas in the perforated exhaust pipe 105, but since the inner space area 108 is required inside the glass wool layer 110, only that much. , The muffling effect is reduced. The present invention has been made to solve the above problems, and an object thereof is to provide a sound absorbing silencer that can prevent thermal deterioration of the glass wool layer and improve the sound deadening effect.

According to the first aspect of the present invention,
A perforated exhaust pipe, a cylindrical body surrounding the perforated exhaust pipe and forming a muffling chamber between the perforated exhaust pipe and a muffler chamber. And a perforated cylindrical partition tube that forms an outer silencing area, a metal wool layer that is disposed in the inner silencing area and is supported on the outer peripheral surface of the perforated exhaust pipe, and a glass wool layer that is filled in the outer silencing area. It is characterized by being The invention according to claim 2 is characterized in that, in the invention according to claim 1, an annular space region is formed outside the metal wool layer in the inner sound deadening region.

According to the first aspect of the invention, the metal wool layer functions as a heat insulating material that blocks heat conduction between the glass wool layer and the porous exhaust pipe. The high temperature heat is cut off, and the temperature of the exhaust gas in the glass wool layer becomes lower than the temperature in the porous exhaust pipe. Also,
The metallic wool layer is supported on the outer peripheral surface of the perforated exhaust pipe without scattering like the glass wool layer, and exhaust noise is silenced by the metallic wool layer and the glass wool layer. According to the second aspect of the invention, since the annular space area is formed outside the metal wool layer in the inner sound deadening area, the amount of the metal wool layer used is reduced.

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a sound absorbing silencer according to an embodiment of the present invention. In this embodiment, an example in which a sound absorbing silencer is applied to a primafra will be described. In the drawing, reference numeral 1 is a silencer body, which is a cylinder body 2 and end plates 3 for closing both ends of the cylinder body 2.
And 4. The porous exhaust pipe 5 penetrates through the central portions of the end plates 3 and 4, and the porous exhaust pipe 5 is formed with a plurality of small holes 5A. In this way, the tubular body 2 surrounds the porous exhaust pipe 5, and the muffling chamber 6 is formed between the tubular body 2 and the porous exhaust pipe 5. A perforated cylindrical partition pipe 7 is arranged in the muffling chamber 6, the perforated cylindrical partition pipe 7 has a plurality of small holes 7A, and the muffler chamber 6 is radially divided to divide the inner silencing region 8 and the outer silencing region 9 into one.
Is formed. Further, the metal wool layer 10 is supported on the outer peripheral surface 5B of the porous exhaust pipe 5 and arranged in the inner sound deadening region 8. The metal wool layer 10 has a wire diameter of 30 μm to 40
It is a cylindrical shape formed by intertwining metal fiber materials having various lengths and short lengths of μm. The metal fiber material is made of a ferritic stainless steel alloy such as SUS430M. The metal fiber materials intertwined with each other have a strong deformation holding force, so that it is possible to form a cylindrical shape. The metal wool layer 10 is fixed to the porous exhaust pipe 5 by resistance welding. The resistance-welded portion of the metal wool layer 10 is securely fixed without being dented but the periphery thereof being cut. The outer muffling area 9 is filled with a glass wool layer 11. Glass wool layer 1
1 is made of a fibrous material containing silicon oxide as a main component and has a cotton shape. The metal wool layer 10 has a higher density than the glass wool layer 11 and is more likely to receive sound. When the metal wool layer 10 and the glass wool layer 11 have the same density, the metal wool layer 10 has a larger sound absorbing effect than the glass wool layer 11. Further, since the metal wool layer 10 has a higher thermal conductivity than the glass wool layer 11, heat does not stay at a specific portion of the metal wool layer 10, thermal melting loss is prevented, and a substantial heat resistant temperature is obtained. Is higher than the heat resistant temperature of the glass wool layer 11. Then, in the inner sound deadening area 8, an annular space area 12 is formed outside the metal wool layer 10. In the present embodiment, however, the metal wool layer 10 is entangled with the metal fiber materials one by one to form one cylindrical shape as a whole.
It is supported on the outer peripheral surface 5B of the perforated exhaust pipe 5 without being scattered by the exhaust gas like the glass wool layer 11, and exhaust noise is caused by the metal wool layer 10 and the glass wool layer 11
The sound is muted in two steps. Further, since the metal wool layer 10 functions as a heat insulating material that blocks heat transfer between the glass wool layer 11 and the porous exhaust pipe 5, the metal wool layer 10 blocks high-temperature heat in the porous exhaust pipe 5, The temperature of the exhaust gas in the glass wool layer 11 becomes lower than the temperature in the porous exhaust pipe 5. According to the above-described configuration, the metal wool layer 10 functions as a heat insulating material that blocks heat transfer between the glass wool layer 11 and the porous exhaust pipe 5, so that the metal wool layer 10 is contained in the porous exhaust pipe 5. The high temperature heat is blocked, and the temperature of the exhaust gas in the glass wool layer 11 becomes lower than the temperature in the porous exhaust pipe 5, so that the thermal deterioration of the glass wool layer 11 can be prevented. Further, since the metal wool layer 10 is made of metal fiber material and has a cylindrical shape by intertwining the metal fiber material, it is supported on the outer peripheral surface of the porous exhaust pipe 5 without scattering like the glass wool layer 11. To be done.
Therefore, it is possible to provide a sound absorbing material in two stages of the metal wool layer 10 and the glass wool layer 11, and exhaust noise can be silenced by the metal wool layer 10 and the glass wool layer 11.
The muffling effect can be improved. Further, in the inner sound deadening area 8, since the annular space area 12 is formed outside the metal wool layer 10, the radius of the glass wool layer 11 becomes large, and the surface area of the glass wool layer 11 that contacts the perforated cylindrical partition tube 7 is increased. And the sound absorption effect is increased. Since the metal wool layer 10 has a larger sound absorbing effect than the glass wool layer 11, the amount of the glass wool layer 11 used can be reduced in order to secure the same sound absorbing effect. In the present embodiment, the primafra is taken as an example of the sound absorbing silencer, but the present invention is not limited to this, and for example, the tip of the exhaust lead-out pipe of the silencer as in FIG. 3 of the conventional example. It is also possible to provide a sound absorbing type silencer. Further, a sound absorbing silencer can be provided in the resonance pipe and the exhaust introduction pipe. Further, in the present embodiment, the annular space region is formed outside the metal wool layer in the inner sound deadening region, but the entire inner sound deadening region can be filled with the metal wool layer. In this case, since the volume of the metal wool layer increases, the sound absorbing effect can be increased. Further, in this embodiment, SUS430M is used as the material of the metal wool layer 10, but the material is not limited to such a material. In addition, in the present embodiment, the metal wool layer 10 is formed by intertwining metal fiber materials having a wire diameter of 30 μm to 40 μm and various long and short lengths entangled to form a cylindrical shape. , Metal wool layer 1
No. 0 is not limited to such a mode, and for example, knitted metal fiber material may be compression-molded and fixed to the porous exhaust pipe 5 by resistance welding.

As described above, according to the first aspect of the present invention, the metal wool layer functions as a heat insulating material that blocks heat transfer between the glass wool layer and the porous exhaust pipe. The layer blocks high temperature heat in the perforated exhaust pipe,
The temperature of the exhaust gas in the glass wool layer becomes lower than the temperature in the porous exhaust pipe, and thermal deterioration of the glass wool layer can be prevented. Further, the metal wool layer is supported on the outer peripheral surface of the perforated exhaust pipe, and exhaust noise can be silenced by the metal wool layer and the glass wool layer without scattering unlike the glass wool layer. That is, since the metal wool layer is supported on the outer peripheral surface of the perforated exhaust pipe, it is possible to provide a sound absorbing layer in two stages of the metal wool layer and the glass wool layer, and exhaust noise is reduced by the metal wool layer and the glass wool layer. You can mute in steps and improve the muffling effect. According to the invention described in claim 2, since the annular space region is formed outside the metal wool layer in the inner sound deadening region, the amount of the metal wool layer used can be reduced and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a sound absorbing silencer according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the sound absorbing silencer.

FIG. 3 is a vertical cross-sectional view of a conventional sound absorbing silencer.

FIG. 4 is a cross-sectional view of the sound absorbing silencer.

[Explanation of symbols]

 2 Cylindrical body 5 Perforated exhaust pipe 6 Silencer chamber 7 Perforated cylindrical partition pipe 8 Inner silencing area 9 Outer silencing area 10 Metal wool layer 11 Glass wool layer 12 Annular space area

Claims (2)

[Claims] 1. A perforated exhaust pipe (5), and a tubular body (2) which is arranged so as to surround the perforated exhaust pipe (5) and forms a silencing chamber (6) between the perforated exhaust pipe (5). A perforated cylindrical partition pipe (7) disposed in the silencing chamber (6) and radially dividing the silencing chamber (6) to form an inner silencing region (8) and an outer silencing region (9), A metal wool layer (10) disposed in the inner sound deadening region (8) and supported on the outer peripheral surface (5B) of the porous exhaust pipe (5), and a glass wool layer (11) filled in the outer sound deadening region (9). )
A sound-absorbing silencer characterized by having and. 2. The sound deadening silencer according to claim 1, wherein an annular space area (12) is formed outside the metal wool layer (10) in the inner sound deadening area (8).