JP2008106726A - Muffler for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a muffler for an internal combustion engine reduced in weight by making it from a synthetic resin. <P>SOLUTION: This muffler for an internal combustion engine comprises an outer shell 1 having a cylindrical part 1a and cover parts 1b, 1c closing the both ends thereof. A cylindrical inner shell 2 is disposed in the outer shell 1 to form a resonance chamber 8 between the outer shell 1 and the inner shell 2. The outer periphery of an inlet pipe 10 is brought into contact with the inner periphery of the inner shell 2. An outlet pipe 22 is pulled out from the inside of the inner shell 2 to the outside of the outer shell 1 through the cover part 1c. Through holes 16, 18 allowing the inside of the inlet pipe 10 to communicate with the resonance chamber 8 are formed in the inlet pipe 10 and the inner shell 2, respectively. The cylindrical part 1a of the outer shell 1 is formed integrally with the cover part 1b closing one end of the cylindrical part 1a with a synthetic resin. The cover part 1c closing the other end of the cylindrical part 1a is formed integrally with the outlet pipe 22 with a synthetic resin. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a muffler for an internal combustion engine mounted on an exhaust system of an automobile.

Conventionally, as disclosed in Patent Document 1 and Patent Document 2, a metal branch pipe is branched from an exhaust pipe, and a synthetic resin resonator is provided at the tip of the branch pipe to reduce exhaust noise. Proposed. By providing a resonator via a branch pipe, the resonator is isolated from high-temperature exhaust, and by making the resonator made of synthetic resin, it can have a free appearance and structure that takes advantage of the moldability of the resin, and is lightweight. Can be achieved.
JP-A-9-144525 JP 2000-8830 A

  However, in such a conventional one, since it is provided via the branch pipe, it is isolated from the high temperature of the exhaust system. However, the muffler for the internal combustion engine cannot be reduced in weight because it is made of a synthetic resin. Since it is made of metal, there is a problem that it is difficult to reduce the weight.

  The subject of this invention is providing the muffler for internal combustion engines which can achieve weight reduction as a product made from a synthetic resin.

In order to achieve this problem, the present invention has taken the following measures in order to solve the problem. That is,
A muffler for an internal combustion engine including an inlet pipe that is covered with an outer shell having a cylindrical portion and a lid portion that closes both ends thereof, into which exhaust gas discharged from the internal combustion engine is introduced, and an outlet pipe that discharges the exhaust gas. In
At least the cylindrical portion of the outer shell is formed of a synthetic resin, and a cylindrical inner shell is disposed in the outer shell to form a resonance chamber between the outer shell and the inner shell. An outer periphery is provided in contact with an inner periphery of the inner shell, and the outlet pipe is drawn out of the inner shell through the lid portion and out of the outer shell, and passes through the inlet pipe and the resonance chamber. A muffler for an internal combustion engine is characterized in that a hole is formed in the inlet pipe and the inner shell.

  The end of the inlet pipe in the inner shell may be closed and a small hole communicating with the inner shell may be formed in the inlet pipe. Further, the cylindrical portion of the outer shell and the lid portion that closes one end of the cylindrical portion are integrally formed of synthetic resin, and the lid that closes the other end of the cylindrical portion It is good also as a structure which formed the part and the said outlet pipe integrally with the synthetic resin.

  The outlet pipe and the inner shell may be made of metal, and the outlet pipe may be inserted into the outer shell via an interposed member. Moreover, it is good also as a structure which supported the both ends of the said inner shell to the said outer shell via the interposed member.

  Alternatively, the cylindrical portion of the outer shell and the lid portion that closes one end of the cylindrical portion are integrally formed of synthetic resin, and the lid that closes the other end of the cylindrical portion It is good also as a structure which formed a part in the separate body with the synthetic resin, and inserted the said metal outlet pipe into the said cover part through the interposed member.

  In that case, it is good also as a structure which provided the connection member which connects the said outlet pipe and the said inlet pipe in the said inner shell. Moreover, it is good also as a structure which fixed the outer periphery of the said outlet pipe and the outer periphery of the said inlet pipe to the inner periphery of the said inner shell, and connected the said outlet pipe and the said inlet pipe. Alternatively, the connecting member may be a connecting pipe partitioned in the shape of θ along the axial direction, and the outlet pipe may be attached to one of the connecting pipes and the inlet pipe may be attached to the other. Furthermore, it is good also as a structure which attached the channel | path member which forms the channel | path for resonance which connects the said resonance chamber and the said through-hole to the outer periphery of the said inner shell.

  In the muffler for an internal combustion engine of the present invention, the inner shell and the inlet pipe that are exposed to high-temperature exhaust are made of metal, and the resonance chamber is formed between the outer shell and the inner shell. Therefore, at least the cylindrical portion of the outer shell is made of synthetic resin. It is possible to reduce the weight.

  By forming a small hole in the inlet pipe, the exhaust can be guided well into the inner shell. In addition, the cylindrical part and one lid part are integrally formed of synthetic resin, and the other lid part and the outlet pipe are integrally formed of synthetic resin, thereby reducing the number of parts and easy assembly. become.

  By providing the interposed member, the interposed member can be easily provided with heat insulation and heat resistance, and even if one of them is made of synthetic resin, deformation due to heat can be prevented. Further, when the inlet pipe and the outlet pipe are connected by the connecting member, the rigidity is improved, and the vibration between the inlet pipe and the outlet pipe can be prevented. Alternatively, when the inlet pipe and the outlet pipe are fixed to the inner shell, vibration can be prevented without increasing the number of parts. Furthermore, if a passage member is provided on the outer periphery of the inner shell, the resonance effect can be improved.

The best mode for carrying out the present invention will be described below in detail with reference to the drawings.
As shown in FIG. 1, reference numeral 1 denotes an outer shell, and the outer shell 1 includes a cylindrical portion 1a formed in a cylindrical shape, and a lid portion 1b that closes one end of the cylindrical portion 1a, and the cylindrical portion 1a and the lid portion. 1b is integrally formed of a synthetic resin. Further, the outer shell 1 includes a separate lid portion 1c that closes the other end side of the cylindrical portion 1a, and the inside of the outer shell 1 is formed in a hollow shape. In addition, since the cylindrical part 1a is resin-molded with a metal mold | die, the inner and outer periphery is formed in the taper shape. The cylindrical portion 1a is not limited to a cylindrical shape, and may be a rectangular tube shape such as a square or a hexagon, or may be an elliptical tube shape.

  A cylindrical inner shell 2 is disposed in the outer shell 1, and the inner shell 2 is made of metal. The outer diameter of the inner shell 2 is formed smaller than the inner diameter of the cylindrical portion 1a, and the inner shell 2 is formed to be equal to or longer than the length of the cylindrical portion 1a. The inner shell 2 is formed in such a length that both ends of the inner shell 2 reach the inside of the lid portions 1b and 1c so as to be sandwiched between the lid portions 1b and 1c of the outer shell 1.

  Interposing members 4 and 6 are respectively attached to both ends of the inner shell 2, and both ends of the inner shell 2 are respectively attached to both lid portions 1 b and 1 c of the outer shell 1 via the interposing members 4 and 6. A ring-shaped resonance chamber 8 is formed between the inner periphery of the outer shell 1 and the outer periphery of the inner shell 2. The interposed members 4 and 6 are formed of a heat insulating material, or are formed of a resin having higher heat resistance than the synthetic resin of both the lid portions 1 b and 1 c of the outer shell 1. An expansion chamber 9 is formed by the inner shell 2 and the lid portions 1b and 1c.

  An inlet pipe 10 is inserted into one lid portion 1b. At the time of insertion, a ring-shaped interposing member 12 is provided between the lid portion 1b and the inlet pipe 10, and the lid portion 1b and the inlet pipe 10 are provided. It is comprised so that and may not contact directly. The intervention member 12 is formed of a heat insulating material, or is formed of a resin having higher heat resistance than the synthetic resin of the outer shell 1. The inlet pipe 10 is connected to an upstream exhaust passage to introduce exhaust from the internal combustion engine.

  The inlet pipe 10 is inserted so as to be provided inside the inner shell 2, and is arranged so that the outer periphery of the inlet pipe 10 is in contact with the inner periphery of the inner shell 2. A cap member 14 is fitted at the tip of the inlet pipe 10 inserted into the inner shell 2, and the tip of the inlet pipe 10 is closed.

  Through holes 16 and 18 communicating with the inlet pipe 10 and the resonance chamber 8 are formed in the inlet pipe 10 and the inner shell 2 at contact portions between the inlet pipe 10 and the inner shell 2, respectively. The inlet pipe 10 has a large number of small holes 20, and the expansion chamber 9 in the inlet pipe 10 and the inner shell 2 communicate with each other.

  An outlet pipe 22 is attached to the separate lid portion 1 c, and the outlet pipe 22 is provided by being drawn out of the outer shell 1 from the expansion chamber 9 in the inner shell 2. The lid portion 1c and the outlet pipe 22 are integrally formed of a synthetic resin, and the wall surface of the outlet pipe 22 is formed in a taper shape because the outlet pipe 22 is molded by a mold. The separate lid portion 1c is covered so as to close one end of the cylindrical portion 1a, and its peripheral edge is welded or the like, so that the lid portion 1c is integrated with the cylindrical portion 1a and covered with the outer shell 1. ing.

  The outlet pipe 22 in the expansion chamber 9 is provided with a metal covering member 24 so as to cover the outer periphery thereof, and the sound deadening chamber 26 is provided between the outer periphery of the outlet pipe 22 and the inner periphery of the covering member 24. Is formed. The outlet pipe 22 has a large number of small holes 28 communicating with the sound deadening chamber 26. The sound deadening chamber 26 may be filled with glass wool or the like.

Next, the operation of the muffler for the internal combustion engine of the present embodiment described above will be described.
When exhaust gas is guided from the upstream exhaust flow path to the inlet pipe 10, the exhaust gas flows into the expansion chamber 9 through a large number of small holes 20. Then, the gas is discharged from the expansion chamber 9 through the outlet pipe 22 to the downstream exhaust passage.

  When the exhaust gas flows into the inlet pipe 10, a sound absorbing effect is obtained and the exhaust noise is reduced by the action as a resonator by the through holes 16 and 18 and the resonance chamber 8. Further, when the exhaust gas flows into the expansion chamber 9 from the small hole 20, the exhaust noise is reduced due to the expansion of the exhaust gas. Further, when the exhaust gas is discharged from the expansion chamber 9 through the outlet pipe 22, the exhaust noise is reduced by the small hole 28 and the muffler chamber 26 of the outlet pipe 22.

  Exhaust gas flows into the expansion chamber 9 from the inlet pipe 10 through the small hole 20 and is discharged from the expansion chamber 9 through the outlet pipe 22. Therefore, the hot exhaust gas does not flow directly into the resonance chamber 8, and the cylindrical portion 1a and the lid portions 1b, 1c of the outer shell 1 are not directly exposed to the hot exhaust gas. In particular, the cylindrical portion 1a is not exposed to high-temperature exhaust.

  Therefore, since the inner shell 2 and the inlet pipe 10 exposed to high-temperature exhaust are made of metal and the outer shell 1 can be kept at 300 ° C. or lower, the outer shell 1 composed of the cylindrical portion 1a and the lid portions 1b and 1c is synthesized. It can be made of resin, and the weight can be reduced. Moreover, since the outer shell 1 can be resin-molded, mass productivity is improved, the degree of freedom of the shape is high, and it becomes easy to form the shape according to the vehicle to be mounted.

  In that case, weight reduction can be achieved by making at least the cylindrical part 1a into a product made of synthetic resin. Further, the cylindrical portion 1a and the one lid portion 1b are integrally made of synthetic resin, and the other lid portion 1c and the outlet pipe 22 are integrally made of synthetic resin, thereby reducing the number of parts and assembling. Becomes easier. Furthermore, by providing the interposed members 4, 6, and 12, the interposed members 4, 6, and 12 can be provided with heat insulation and heat resistance, and the outer shell 1 can be prevented from being deformed by heat.

  Next, a muffler for an internal combustion engine according to a second embodiment different from the above-described embodiment will be described with reference to FIGS. The same members as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The same applies below.

  The outlet pipe 22 is different from the above-described embodiment. In the second embodiment, the outlet pipe 32 is formed of a metal pipe, and is formed separately from the lid portion 1 d of the outer shell 1. The lid portion 1d of the outer shell 1 is formed of a synthetic resin, like the separate lid portion 1c described above.

  The outlet pipe 32 is provided so as to be inserted into the lid portion 1 d and pulled out from the expansion chamber 9 in the inner shell 2 to the outside of the outer shell 1. A ring-shaped interposition member 34 is provided between the outlet pipe 32 and the lid portion 1d so that the outlet pipe 32 and the lid portion 1d are not in direct contact with each other. The interposed member 34 is formed of a heat insulating material, or is formed of a resin having higher heat resistance than the synthetic resin of the lid portion 1d.

  A connecting member 36 is fixed to the inlet pipe 10 and the outlet pipe 32 in the inner shell 2 by welding or the like, and the inlet pipe 10 and the outlet pipe 32 are connected by the connecting member 36.

  In this way, the outlet pipe 32 is made of metal, and the inlet pipe 10 and the outlet pipe 32 are connected by the connecting member 36, whereby the rigidity is improved and the vibration between the inlet pipe 10 and the outlet pipe 32 can be prevented. Further, similarly to the above-described embodiment, the outer shell 1 composed of the cylindrical portion 1a and the lid portions 1b and 1d can be formed of a synthetic resin, and the weight can be reduced.

Next, the muffler for the internal combustion engine of the third embodiment will be described with reference to FIGS.
In the third embodiment, the outer periphery of the inlet pipe 10 is brought into contact with the inner periphery of the inner shell 2 and fixed by welding or the like, as in the above-described embodiment. The outer periphery of the metal outlet pipe 32 is also brought into contact with the inner periphery of the inner shell 2 and fixed by welding or the like.

  As a result, rigidity is improved, vibrations of the inlet pipe 10 and the outlet pipe 32 can be prevented, and the number of parts can be reduced. As described above, the outer shell 1 including the cylindrical portion 1a and the lid portions 1b and 1d. Can be formed of a synthetic resin, and the weight can be reduced.

Next, an internal combustion engine muffler according to a fourth embodiment will be described with reference to FIGS.
In the fourth embodiment, a connecting pipe 41 is disposed in the inner shell 2. A partition plate 42 is provided in the connection pipe 41 along the axial direction, and the connection pipe 41 is partitioned into a first passage 41 a and a second passage 41 b in a θ shape.

  One end of the inlet pipe 42 inserted through the interposition member 12 into the lid portion 1b is inserted into the end of the first passage 41a of the partitioned connecting pipe 41, and the inlet pipe 42 and the first passage 41a are connected to each other. It is communicated. A cap member 44 is fitted and closed at the other end of the first passage 41a.

  A cap member 46 is fitted and closed at one end of the second passage 41b. In addition, one end of an outlet pipe 48 inserted into the lid portion 1d via the interposition member 34 is inserted into the other end of the second passage 41b, and the outlet pipe 48 and the second passage 41b communicate with each other. Yes. The connecting pipe 41 is provided with a large number of small holes 50 and 52, and the first passage 41 a and the second passage 41 b communicate with the expansion chamber 9.

  The exhaust gas introduced into the inlet pipe 42 flows into the first passage 41a from the inlet pipe 42, and flows into the expansion chamber 9 through the small hole 50 from the first passage 41a. And it flows in into the 2nd channel | path 41b through the small hole 52 from the expansion chamber 9, and flows out through the outlet pipe 48 from the 2nd channel | path 41b.

  In the fourth embodiment, since the inlet pipe 42 and the outlet pipe 48 are connected by the connecting pipe 41 as the connecting member, vibrations of the inlet pipe 42 and the outlet pipe 48 can be prevented, and as described above. The outer shell 1 composed of the cylindrical portion 1a and the lid portions 1b and 1d can be formed of a synthetic resin, and the weight can be reduced.

Next, an internal combustion engine muffler according to a fifth embodiment will be described with reference to FIGS.
In the fifth embodiment, a passage member 60 is attached to the outer periphery of the inner shell 2 in accordance with the through hole 18 with respect to the muffler for the internal combustion engine of the embodiment shown in FIGS. The resonance passage 62 is formed between the passage member 60 and the inner shell 2, and the passage member 60 is disposed so that the resonance passage 62 communicates with the through hole 18.

  Further, the cross-sectional shape of the passage member 60 is formed in a U-shape, and one of the passage members 60 is closed, and one of the resonance passages 62 is closed. Are opened in the resonance chamber 8. By providing the resonance passage 62, the resonance effect can be enhanced.

  The present invention is not limited to such embodiments as described above, and can be implemented in various modes without departing from the gist of the present invention.

It is sectional drawing along the axial direction of the muffler for internal combustion engines as one Embodiment of this invention. It is AA sectional drawing of FIG. It is sectional drawing along the axial direction of the muffler for internal combustion engines as 2nd Embodiment. It is BB sectional drawing of FIG. It is sectional drawing along the axial direction of the muffler for internal combustion engines as 3rd Embodiment. It is CC sectional drawing of FIG. It is sectional drawing along the axial direction of the muffler for internal combustion engines as 4th Embodiment. It is DD sectional drawing of FIG. It is sectional drawing along the axial direction of the muffler for internal combustion engines as 5th Embodiment. It is EE sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Outer shell 1a ... Cylindrical part 1b, 1c, 1d ... Cover part 2 ... Inner shell 4, 6, 12, 34 ... Interposition member 8 ... Resonance chamber 9 ... Expansion chamber 10, 42 ... Inlet pipe 16, 18 ... Through Holes 20, 28, 50 ... Small holes 22, 32, 48 ... Outlet pipe 24 ... Cover member 26 ... Silencer chamber 36 ... Connection member 41 ... Connection pipe 42 ... Partition plate 60 ... Path member 62 ... Resonance passage

Claims (10)

A muffler for an internal combustion engine including an inlet pipe that is covered with an outer shell having a cylindrical portion and a lid portion that closes both ends thereof, into which exhaust gas discharged from the internal combustion engine is introduced, and an outlet pipe that discharges the exhaust gas In
At least the cylindrical portion of the outer shell is formed of a synthetic resin, and a cylindrical inner shell is disposed in the outer shell to form a resonance chamber between the outer shell and the inner shell. An outer periphery is provided in contact with an inner periphery of the inner shell, and the outlet pipe is drawn out of the inner shell through the lid portion and out of the outer shell, and passes through the inlet pipe and the resonance chamber. A muffler for an internal combustion engine, wherein a hole is formed in the inlet pipe and the inner shell.   2. The muffler for an internal combustion engine according to claim 1, wherein an end of the inlet pipe in the inner shell is closed and a small hole communicating with the inner shell is formed in the inlet pipe.   The cylindrical portion of the outer shell and the lid portion that closes one end of the cylindrical portion are integrally formed of synthetic resin, and the lid portion that closes the other end of the cylindrical portion; 3. The muffler for an internal combustion engine according to claim 1, wherein the outlet pipe is integrally formed with a synthetic resin.   The said inlet pipe and the said inner shell are metal, The said inlet pipe was inserted in the said cover part of the said outer shell via the interposed member, The Claim 1 thru | or 3 characterized by the above-mentioned. Muffler for internal combustion engine.   The muffler for an internal combustion engine according to any one of claims 1 to 4, wherein both ends of the inner shell are supported by the outer shell via an interposed member.   The tubular portion of the outer shell and the lid portion that closes one end of the tubular portion are integrally formed of synthetic resin, and the lid portion that closes the other end of the tubular portion is formed 3. The internal combustion engine according to claim 1, wherein the internal combustion engine is formed separately from a synthetic resin and is inserted into the lid portion of the separate body via an interposition member through the metal outlet pipe. Engine muffler.   The muffler for an internal combustion engine according to claim 6, further comprising a connecting member that connects the outlet pipe and the inlet pipe in the inner shell.   The internal pipe for the internal combustion engine according to claim 6, wherein an outer periphery of the outlet pipe and an outer periphery of the inlet pipe are fixed to an inner periphery of the inner shell, and the outlet pipe and the inlet pipe are connected. Muffler.   8. The internal combustion engine according to claim 7, wherein the connecting member is a connecting pipe partitioned in the shape of θ along the axial direction, and the outlet pipe is attached to one of the connecting pipes and the inlet pipe is attached to the other. Engine muffler.   10. The internal combustion engine for an internal combustion engine according to claim 1, wherein a passage member that forms a resonance passage that connects the resonance chamber and the through hole is attached to an outer periphery of the inner shell. Muffler.

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