JPH05187218A - Submuffler for automobile - Google Patents

Abstract

PURPOSE:To prevent deterioration of stainless wool and glass wool lowering of a muffling function due to discharge, and prevent the increase of the generation of radiation noise. CONSTITUTION:A submuffler for an automobile comprises an outer shell 1, an outer plate 2, an inner pipe 3 having punched holes 3a, and a muffling chamber 4 surrounded therewith. Stainless wool 5 are arranged to the muffling chamber 4 in a state to surround the outer periphery of the inner pipe 3 and the muffle chamber is filled with glass wool 6. The muffling chamber 4 is provided with a separator 10 having fins 10a for preventing the occurrence of convection.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a sub muffler (front silencer) used in an exhaust system of an automobile.

[0002]

2. Description of the Related Art As shown in FIG. 7, an automobile sub-muffler is surrounded by a cylindrical outer shell 1, outer plates 2 and 2 attached to the front and rear of the outer shell 1, an inner pipe 3 having a punching hole 3a, and an outer pipe. The muffler chamber 4 is provided with stainless wool 5 surrounding the outer circumference of the inner pipe 3 and glass wool 6 is filled therein.

Reference numeral 7 denotes an inner plate which is provided in a number corresponding to the size of the muffler and the required silencing characteristics.
In the above, two inner plates 7 are shown, but the inner plates may not be provided at all.

In this type of sub-muffler, high-temperature, high-pressure, and high-speed exhaust gas flows from the inlet 8 and exits to the outlet 9, while the high-frequency component (500 Hz to 20 kHz) of the exhaust sound is absorbed by the stainless wool 5 and the glass wool 6. Only low frequency components are contained in the exhaust gas and are discharged from the outlet 9.

FIG. 8 is an enlarged view of the upper left portion of the sub-muffler of FIG. 7 to explain the flow of exhaust gas and heat. Arrow A indicates the flow of exhaust gas flowing from the inlet 8 to the outlet 9 in the inner pipe 3. An arrow B indicates a flow flowing from the inner pipe 3 into the silencing chamber 4 through the punching hole 3a,
An arrow C indicates a flow returning from the muffling chamber 4 to the inner pipe 3, and an arrow D indicates a flow of exhaust gas and a heat flow flowing in the glass wool 6 from the upstream left side to the downstream right side.

An arrow E indicates a heat flow outflowing from the inner pipe 3 to the outer shell 1 via the outer plate 2, the inner plate 7, etc., and an arrow F indicates a heat flow outflowing from the outer shell 1 to the outside.

[0007]

SUMMARY OF THE INVENTION In the above conventional technique,
When the exhaust gas flows indicated by the arrows B and C occur, the hot exhaust gas and the heat flow flow from the upstream side to the downstream side in the glass wool 6 as shown by the arrow D, and the temperatures of the stainless wool 5 and the glass wool 6 rise. At the same time, due to pulsation, the fibers of these sound absorbing materials are altered / fatigue and stick to the inside, or short cuts are released to the outside of the muffler, making it difficult to absorb the high frequency components of the exhaust sound, and the flow B directly It has reached the outer shell 1 to excite the outer shell 1 and to cause an increase in radiated sound from the outer shell 1.

FIG. 9 schematically shows a deterioration region of the sound absorbing material when this type of sub-muffler is used for a long time.
α indicates a deteriorated area of stainless wool generated on the stainless wool 5, and β indicates a deteriorated area of glass wool generated on the glass wool 6. Further, G indicates a sound emitted from the outer shell 1.

In this way, the stainless wool deterioration area α
When both sound absorbing materials deteriorate in the glass wool deterioration region β, the inside of the muffler becomes hollow, and the high temperature, high pressure exhaust gas directly excites the outer shell, increasing not only the sound emitted from the sub muffler but also the sound absorbing material's original There is a problem that the performance of the sub-muffler is deteriorated because the sound absorption of high frequency components in the exhaust gas, which is the purpose, is also deteriorated.

Therefore, an object of the present invention is to provide a sub-muffler for automobiles which can solve such problems.

[0011]

In order to achieve the above object, a sub-muffler of the present invention comprises an outer shell (1), an outer plate (2), an inner pipe (3) having a punching hole (3a). It has a muffler room (4) surrounded by these, and an inner pipe (3) is provided in the muffler room (4).
In a sub-muffler for an automobile, which is provided with stainless wool (5) surrounding the outer circumference of the glass and is filled with glass wool (6), a silencer (4) is provided with a separator (10) having a convection prevention fin (10a). And

[0012]

The separator (10) having the convection prevention fins (10a) prevents the flow of exhaust gas and heat shown by the arrow F in FIG. 8 and reduces the flow of exhaust gas shown by the arrows B and C. To do. Further, the heat accumulated in the sound deadening chamber (4) is effectively released to the outer shell (1) through the convection prevention fins, and the temperature rise of the sound absorbing material is reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the first embodiment shown in FIGS. 1 and 2, 1 is a cylindrical outer shell, 2 and 2 are outer plates attached to the front and back of the outer shell, and 3 is an inner pipe having punching holes 3a. It is fixed to the outer plates 2 and 2. 4 is a sound deadening chamber, 5 is stainless wool for sound absorption provided around the outer circumference of the inner pipe 3, 6 is glass wool for sound absorption filled in the sound deadening chamber 4, 7 is an inner plate, 8 is an inlet, 9 is an outlet Then, these structures are the same as those of the above-mentioned prior art.

Reference numeral 10 denotes a separator having a convection prevention fin 10a, which is provided in each of the three silencing chambers 4 surrounded by the outer shell 1, the outer plates 2 and 2, and the inner pipe 3.

The separator 10 is formed of a metal material in such a manner that two cylindrical convection preventing fins 10a are integrally projected on both left and right sides of a disk-shaped portion 10b for partitioning the silencing chamber 4 into left and right. Has been done. And the disk-shaped portion 10
The inner circumference and the outer circumference of b are bent and formed similarly to the inner plate 7, and are fixed to the inner pipe 3 and the outer shell 1.

The flow of exhaust gas and heat of the first embodiment is shown in FIG. The arrow A indicates the flow of exhaust gas flowing from the inlet 8 to the outlet 9 in the inner pipe 3, the arrow B'indicates the flow from the inner pipe 3 into the muffling chamber 4 through the punching hole 3a, and the arrow C'indicates the muffling chamber 4. The flow returning to the inner pipe 3 eliminates the flow of the arrow D described in the related art of FIG.

The arrow E indicates the flow of heat flowing from the inner pipe 3 to the outer shell 1. In addition to the conduction by the outer plate 2 and the inner plate 7 as in the prior art, the conduction by the separator 10 is added. An arrow F indicates a heat flow that flows out from the outer shell 1 and an arrow G indicates a flow that the heat inside the glass wool 6 is released to the outside through the separator 10.

FIG. 4 schematically shows the deterioration region of the sound absorbing material when the sub-muffler of the first embodiment is used for a long period of time. Α'is a deterioration region of stainless wool and β'is a deterioration region of glass wool. From the case of the conventional technique shown in FIG.
The deterioration area is small. G'denotes the radiated sound from the outer shell 1. The radiated sound G'is obtained by the fact that the separators 10 can greatly reduce both deterioration regions α'and β'and that the separator 10 directly limits the vibration of the outer shell 1. It can be made smaller than the pressure amplitude and the radiated sound G of the prior art.

FIG. 5 shows a second embodiment of the present invention, which is different from the first embodiment in that some convection-preventing fins 10a of the separator 10 are provided with some punching holes. FIG. 6 shows a third embodiment of the present invention, in which an inner plate is not used, the muffling chamber is entirely partitioned by the separators 10, and a total of 11 separators 10 are provided. Further, the number of convection prevention fins of these separators 10 is different from that of the first and second embodiments.

The shape and material of the separator 10 are not limited to the shapes and materials of the above-mentioned first to third embodiments, and various modifications can be considered. The disc-shaped portion of the separator and the convection prevention fin may be separately formed and coupled (FIGS. 3 and 4), or a porous material may be used.

[0021]

Since the present invention is constructed as described above, the flow of exhaust gas into stainless wool or glass wool is reduced, and the temperature rise of both sound absorbing materials is reduced. Fatigue deterioration is suppressed. Also, the sound emitted from the outer shell is reduced.

As a result, the properties and reliability of the sub muffler can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a first embodiment of the present invention.

FIG. 2 is a perspective view of the separator of the embodiment of FIG.

FIG. 3 is a diagram for explaining the flow of exhaust gas and heat in the embodiment of FIG.

4A and 4B are views for explaining a deteriorated region and radiated sound of the sound absorbing material of the embodiment of FIG.

FIG. 5 is a vertical sectional view of a second embodiment of the present invention.

FIG. 6 is a vertical sectional view of a third embodiment of the present invention.

FIG. 7 is a vertical cross-sectional view of a conventional technique.

FIG. 8 is a diagram illustrating a flow of exhaust gas and heat of a conventional technique.

FIG. 9 is a diagram for explaining a deteriorated region and a radiated sound of a conventional sound absorbing material.

[Explanation of symbols]

 1 Outer Shell 2 Outer Plate 3 Inner Pipe 3a Punching Hole 4 Noise Reduction Room 5 Stainless Wool 6 Glass Wool 10 Separator 10a Convection Prevention Fins

Claims (1)

[Claims] 1. An outer shell (1), an outer plate (2), an inner pipe (3) having a punching hole (3a), and a sound deadening chamber (4) surrounded by these, and a sound deadening chamber (4). ) Is provided with stainless wool (5) surrounding the outer circumference of the inner pipe (3), and in a vehicle sub-muffler filled with glass wool (6), a separator (a) having convection prevention fins (10a) in the muffler chamber (4). A sub-muffler for an automobile, which is provided with 10).