JP2013060920A - Muffling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a muffling device for effectively reducing exhaust sound volume without causing output reduction and weight increase of an engine while having a simple and low-cost structure.SOLUTION: The muffling device includes an inner tube connected to an exhaust pipe, an outer tube covering the inner tube, a first muffling space formed between the outer tube and the inner tube and filled with a sound-absorbing material, a plurality of gas distribution holes formed on a circumferential wall of the inner tube, and an end cup connected to respective upstream side ends of the outer tube and the inner tube. The end cup includes a tail pipe connected to the downstream side end of the inner tube, a partition plate partitioning the downstream side of the first muffling space, a cup-shaped tail cover covering the tail pipe, and a second muffling space formed between the tail pipe and the tail cover, the partition plate includes a first communication hole connecting between the first muffling space and the second muffling space, and the tail pipe includes a second communication hole for making an inner space of the tail pipe communicate with the second muffling space.

Description

  The present invention relates to a silencer that silences sound when exhaust gas is discharged from an engine of a vehicle such as a motorcycle.

  2. Description of the Related Art Conventionally, as a silencer for an engine mounted on a vehicle such as a motorcycle, a straight exhaust type having a passage through which exhaust gas passes straight from the silencer inlet to the outlet is known. More specifically, an inner cylinder that allows exhaust gas from the engine to pass therethrough is disposed substantially concentrically inside the outer cylinder, and a sound-absorbing material is loaded between the inner cylinder and the outer cylinder. It is known that the exhaust gas introduced inside is attenuated by the sound absorbing material by guiding the exhaust gas to the sound absorbing material side through a plurality of punching holes formed over the peripheral surface of the inner cylinder (for example, (See Patent Document 1).

  In the silencer, a punching cone and a tail pipe are concentrically arranged with the inner cylinder at the exhaust gas downstream end portion inside the inner cylinder, and exhaust gas passing through the inner cylinder is removed from the inner cylinder via the punching cone. However, the noise reduction effect is further improved by guiding it to a tail pipe with a small diameter.

  In a straight exhaust silencer, the diameter of the communication hole is increased to further reduce the exhaust noise with the sound absorbing material, the exhaust passage area is increased, the inner diameter of the tail pipe is reduced, and the communication hole is provided in the tail pipe. The provision (for example, refer patent document 2) is examined.

JP 2007-292049 A JP-A-10-252442

  The above-described straight exhaust silencer is generally easy to reduce in weight and is suitable for motocross motorcycles because it is suitable for rapid increase in the number of revolutions and high output characteristics. Motorcycles used off-road like a motocross like a motocross have been allowed to have a higher exhaust volume than a motorcycle running on a public road. However, even for motorcycles used in stadiums, regulations regarding exhaust volume are being strengthened, and there is a demand for a silencer that can exert a greater silencing effect without causing a decrease in engine output. .

  Therefore, a technical problem to be solved by the present invention is to provide a silencer that can effectively reduce the exhaust volume without causing a decrease in engine output and an increase in weight while having a simple and inexpensive configuration. is there.

  In order to solve the above technical problem, the present invention provides the following silencer.

  That is, the silencer according to the present invention is formed between the inner cylinder connected to the exhaust pipe, the outer cylinder covering the inner cylinder, the outer cylinder and the inner cylinder, and filled with a sound absorbing material. A silencer comprising: a first silencing space; a plurality of gas flow holes formed in a peripheral wall of the inner cylinder; and an end cup connected to each downstream end of the outer cylinder and the inner cylinder. The end cup is connected to a downstream end of the inner cylinder; a partition plate connected to the downstream end of the outer cylinder and partitioning the downstream side of the first silencing space; and A cup-shaped tail cover coupled to the downstream end of the outer cylinder and covering the tail pipe; and a second silencing space formed between the tail pipe and the tail cover, the partition plate Communicates the first silencing space and the second silencing space It has a first communication hole having the tail pipe, characterized by having a plurality of second communication holes for communicating the inner space and the second silencing space of the tail pipe.

  In the above invention, preferably, the following configuration can be adopted.

(A) The first communication hole is formed at a position close to the outer cylinder.

(B) The second communication hole is formed to extend in a substantially horizontal direction.

(C) The upstream end portion and the downstream end portion of the tail pipe are connected and fixed to the inner peripheral end portion of the partition plate and the downstream end portion of the tail cover by welding or a sealing agent, respectively. The

(D) A holding member is interposed between the outer peripheral surface of the inner cylinder and the sound absorbing material.

(E) A heat-absorbing sound absorbing material is loaded on the outer cylinder side of the first silencing space.

  According to the present invention, between the first silencing space and the second silencing space and the inner space of the tail pipe through the first communicating hole and the second communicating hole formed in the partition plate and the tail pipe, respectively. The second silencing space communicates with each other. That is, the first silencing space communicates with the inner space of the tail pipe through the first communication hole, the second silencing space, and the second communication hole. A part of the exhaust gas that has entered the inner space of the tail pipe from the inner cylinder passes through the second communication hole and enters the second silencing space to expand and lose energy, and a resonator (resonance in the second silencing space) The exhaust noise is reduced by the effect. At the same time, exhaust gas that has entered the inner space of the tail pipe from the inner cylinder, a plurality of punching holes formed in the inner cylinder, a first silencing space, a first communication hole, a second silencing space, and a second communication hole are provided. Exhaust noise is reduced by causing exhaust interference with the exhaust gas that enters the interior space of the tail pipe.

  According to the configuration (a), since the exhaust path extending from the first silencing space to the second silencing space through the first communication hole formed at a position close to the outer cylinder becomes longer, the exhaust noise is further reduced. .

  According to the configuration (b), since the exhaust path extending from the first communication hole to the inner space of the tail pipe through the second communication hole formed so as to extend in the substantially horizontal direction becomes longer, the exhaust noise is further reduced. Is done.

  According to the configuration (c), the tail pipe, the partition plate, and the tail cover are integrally connected and fixed, so that a long-term stable mounting structure can be obtained, and a second silencing space with high airtightness can be obtained.

  According to the configuration (d), it is possible to prevent the sound absorbing material filled in the first silencing space from protruding into the inner cylinder space through the gas flow hole due to the interposition of the holding member.

  According to the structure (e), since the temperature rise of an outer cylinder can be suppressed, sufficient intensity | strength is maintained about an outer cylinder, and the beauty | look is maintained over a long term.

1 is a left side view of a motorcycle equipped with a silencer according to the present invention. It is a front view of the silencer concerning one embodiment of the present invention. It is a top view of the silencer shown in FIG. It is a longitudinal cross-sectional view of the silencer shown in FIG. It is a longitudinal cross-sectional view of the end cup which comprises the silencer shown in FIG. FIG. 6 is a left side view of the end cup shown in FIG. 5. It is an expanded sectional view of the partition plate along the AA line of FIG. It is a longitudinal cross-sectional view of the partition plate which comprises the end cup shown in FIG.

  Hereinafter, a silencer 10 according to a preferred embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a left side view showing a motorcycle 1 including a silencer 10 according to an embodiment of the present invention. Although a motorcycle 1 for motocross is shown as a preferred example of a vehicle in which the silencer 10 is mounted, the present invention is not limited thereto. The front-rear direction, the left-right direction, and the up-down direction in the present specification refer to the vehicle length direction, the vehicle width direction, and the vehicle height direction of the motorcycle 1 with reference to the time when viewed from the driver's seat on the motorcycle 10 or the like. Each means. Further, the upstream side and the downstream side in the present specification mean the upstream side and the downstream side of the exhaust gases G and G1 flowing in the inner cylinder 10b, respectively. In other words, in the muffler 10, the side of the exhaust pipe 20 is The upstream side, and the end cup 40 side is the downstream side.

  In FIG. 1, a body frame 2a of a motorcycle 1 includes a head pipe 2b at a front end portion thereof, and a front fork 2c that is turnable (steerable) in the left-right direction with respect to the head pipe 2b. 2d is pivotally supported. A rear wheel 3b is pivotally supported at the rear end of the swing arm 3a. An engine 3e is mounted at the center of the body frame 2a. Above the engine 3e, a fuel tank 3c is installed on the front side, and a seat 3d is installed on the rear side.

  An exhaust pipe 20 is connected to an exhaust port formed on the front side of the engine 3e. The exhaust pipe 20 extends rearward through the side of the engine 3e and is disposed above the rear wheel 3b. Connected to the silencer 10. Exhaust gas G discharged from the engine 3e is introduced into the silencer 10 through the exhaust pipe 20, and after the silence of the exhaust gas G is reduced by the silencer 10, the downstream outlet of the end cup 40 50 is discharged to the outside. The silencer 10 is attached to the rear frame 2f by brackets 32 and 33 described later.

  Next, the silencer 10 according to an embodiment of the present invention will be described in detail with reference to FIGS. 2 is a front view of the silencer 10 according to an embodiment of the present invention, FIG. 3 is a top view of the silencer 10 shown in FIG. 2, and FIG. 4 is the silencer shown in FIG. 10 is a longitudinal sectional view of FIG.

  As shown in FIGS. 2 to 4, the silencer 10 according to the present invention has a generally cylindrical shape, and covers an inner cylinder 10b through which exhaust gas G from the exhaust pipe 20 flows, and the inner cylinder 10b. Thus, the outer cylinder 10a disposed substantially concentrically with respect to the inner cylinder 10b, the sound absorbing material 22 loaded in the first silencing space 11 formed between the inner cylinder 10b and the outer cylinder 10a, and the outer cylinder And an end cup 40 connected and fixed to the downstream side of 10a.

  The upstream end 15 a of the outer cylinder 10 a and the exhaust pipe 20 are connected and fixed via a tapered front wall 24 that covers the exhaust pipe 20. The upstream end of the tapered front wall 24 is fitted to the outer peripheral surface of the exhaust pipe 20 and is connected and fixed by welding. The downstream end portion of the tapered front wall 24 is fitted to the inner peripheral surface of the upstream end portion 15a of the outer cylinder 10a, and is connected and fixed by a bolt 17 with a sealant interposed therebetween. . Brackets 32 and 33 for fixing the muffler 10 to the rear frame 2f of the motorcycle 1 are provided at the upper central portion of the outer peripheral surface of the outer cylinder 10a and the outer peripheral side surface of the exhaust pipe 20, respectively.

  The outer cylinder 10a is a tubular body made of, for example, an aluminum alloy material and having an oval cross-sectional shape having a long axis in the vehicle height direction. The cross-sectional shape of the outer cylinder 10a may be an ellipse, a triangle, a quadrangle or more, or a circle.

  The inner cylinder 10b is a cylindrical straight pipe body made of, for example, SUS304 austenitic stainless steel. An inner cylinder space 13 is formed in an inner portion of the inner cylinder 10b. The upstream end 19 a of the inner cylinder 10 b is fitted and connected to the inner peripheral surface of the exhaust pipe 20. The connecting portion may be fixed by welding or may be floating. The downstream end 19 b on the downstream side of the inner cylinder 10 b is fitted and connected to the inner peripheral surface of the tail pipe 44.

  Two pairs of exhaust gas lead-out portions 14 are provided on the peripheral wall of the inner cylinder 10b. Each exhaust gas deriving portion 14 has a shape protruding from the peripheral wall of the inner cylinder 10b toward the axis of the inner cylinder 10b so that the exhaust gas G flowing from the upstream side can be taken in, that is, the peripheral wall of the inner cylinder 10b is It has a curved surface shape recessed toward the inner cylinder space 13 side. Each exhaust gas lead-out part 14 has a tapered shape from the upstream side toward the downstream side. The upstream and downstream exhaust gas deriving portions 14 are opposed to each other at an angle of 180 degrees on the peripheral wall of the inner cylinder 10b. The upstream pair of exhaust gas deriving portions 14 and the downstream pair of exhaust gas deriving portions 14 are spaced apart in a staggered manner along the axial length direction. A notch 18 is formed in the peripheral wall at a position adjacent to the upstream side of each exhaust gas outlet 14. The cut portion 18 is an arcuate slit in which the peripheral wall of the inner cylinder 10b is partially cut in the circumferential direction.

  A large number of small gas flow holes 12 are provided in the peripheral wall of the inner cylinder 10b. The gas flow holes 12 are formed in a staggered manner in the axial length direction so as to avoid the exhaust gas lead-out portion 14 and the cut portion 18 and their peripheral portions. The gas flow holes 12 aligned in the axial direction are also formed in the circumferential direction. The gas flow hole 12 is a hole that is formed by punching and penetrates the peripheral wall of the inner cylinder 10 b, and communicates the inner cylinder space 13 of the inner cylinder 10 b with the first silencing space 11.

  A sound absorbing material 22 is loaded in the first silencing space 11 surrounded by the inner cylinder 10b, the outer cylinder 10a, the tapered front wall 24, and the end cup 40. The sound absorbing material 22 is made of a fibrous material such as glass wool or steel wool. In FIG. 4, the sound absorbing material 22 is illustrated in a form in which the sound absorbing material 22 is arranged substantially evenly in the first silencing space 11, but the illustration of FIG. There is no particular limitation. For example, the sound absorbing material 22 may be distributed and arranged so as to partially fill the first silencing space 11. A holding member 30 is interposed between the outer peripheral surface of the inner cylinder 10 b and the sound absorbing material 22. The holding member 30 is obtained by overlapping and winding a material in which a stainless wool material and an iron wire cloth material are knitted, and the sound absorbing material 22 filled in the first silencing space 11 passes through the gas circulation hole 12 to form an inner cylinder space. 13 is prevented from protruding. Moreover, a heat-absorbing sound absorbing material 23 is loaded between the inner peripheral surface of the outer cylinder 10a and the sound absorbing material 22. For example, the temperature rise of the outer cylinder 10a made of an aluminum alloy material can be suppressed. Therefore, sufficient strength is maintained and aesthetics are maintained for a long time.

  As shown in FIG. 5, the end cup 40 connected to each of the downstream end portions 15 b and 19 b of the outer cylinder 10 a and the inner cylinder 10 b includes a cup-shaped tail cover 42, a tail pipe 44, a partition plate 46, It is equipped with. The tail cover 42 is made of, for example, stainless steel and is tapered toward the downstream side. The wall surface 42 a of the tail cover 42 covers the tail pipe 44 in a state of being separated from the tail pipe 44. An opening is formed in the downstream side wall surface portion 42c of the tail cover 42, and the downstream end portion 44c of the tail pipe 44 is connected and fixed to the inner side surface of the downstream side wall surface portion 42c by welding. The exhaust gas G2 is prevented from flowing out from the portion. A plurality of attachment holes 37 are formed in the upstream end 42 b of the tail cover 42.

  The tail pipe 44 is a cylindrical member made of stainless steel, for example, and has a role of finally exhausting the exhaust gas G flowing into the silencer 10 from the downstream outlet 50 to the outside. The tail pipe 44 has a stepped structure in which the upstream portion 44a of the tail pipe 44 bulges slightly outward from the downstream portion 44d. The tail pipe 44 is configured such that the downstream end 19b of the inner cylinder 10b is fitted to the inner peripheral surface of the upstream portion 44a (shown in FIG. 4).

  Second communication holes 54 extending in the lateral direction (that is, substantially horizontal direction) are formed in the left and right side surface portions on the upstream side in the downstream portion 44d of the tail pipe 44 (shown in FIGS. 5 and 7). The two second communication holes 54 pass through the wall surface of the downstream portion 44 d to communicate the second silencing space 41 and the internal space 43.

  Due to the second communication hole 54, the divided exhaust gas G <b> 2 flowing through the second silencing space 41 flows into the internal space 43, or a part of the straight exhaust gas G <b> 1 flowing through the internal space 43 flows into the second silencing space 41. . Via the second communication hole 54, the shunt exhaust gas G2 flowing from the second silencing space 41 to the internal space 43 of the tail pipe 44, and going straight from the inner cylindrical space 13 of the inner cylinder 10b to the internal space 43 of the tail pipe 44 Exhaust noise is reduced by causing exhaust interference with the exhaust gas G1. A part of the straight exhaust gas G1 flowing through the inner space 43 of the tail pipe 44 flows into the second silencing space 41 through the second communication hole 54 to lose energy and resonate in the second silencing space 41. Due to the (resonator) effect, exhaust noise is reduced.

  The second communication hole 54 described above can be variously modified in addition to the modes illustrated in FIGS. 5 and 7 (that is, the two second communication holes 54 extending in the lateral direction). For example, it may be formed in a manner in which the two are separated in the vertical direction (that is, the vertical direction). In addition, the number of second communication holes 54 formed separately from the side surface portion of the tail pipe 44 may be two or more, such as three, four, or eight. The formation of the second communication hole 54 also in the lateral direction (that is, the substantially horizontal direction) is to prevent the sound absorbing material 22 from flowing out into the shunt exhaust gas G2 and to prevent the first communication hole 54 from flowing out. This contributes to a reduction in exhaust noise due to the longer exhaust path from the communication hole 52.

  The partition plate 46 is a lid-shaped member made of, for example, stainless steel, and serves as a wall surface that partitions the boundary between the first silencing space 11 located on the upstream side and the second silencing space 41 located on the downstream side. have. The partition plate 46 surrounds a wall surface portion 46a, a flange portion 46c that is bent at an angle of about 90 degrees with respect to the wall surface portion 46, and a central opening formed in a central portion of the wall surface portion 46a. And an opening edge 46b. The upstream end 44b of the tail pipe 44 is connected and fixed to the outer surface of the upstream opening edge 46b by welding. A plurality of mounting holes 37 are also formed in the flange portion 46c.

  As shown in FIGS. 4 to 8, a plurality of first communication holes 52 extending in the front-rear direction are formed in the wall surface portion 46 a of the partition plate 46. The first communication hole 52 passes through the wall surface portion 46 a and communicates the first silencing space 11 and the second silencing space 41. The shunt exhaust gas G <b> 2 flows from the first silencing space 11 into the second silencing space 41 through the first communication hole 52. The first communication holes 52 are formed at positions away from the tail pipe 44 and close to the flange portion 46c, in other words, close to the outer cylinder 10a. By disposing the first communication hole 52 in the vicinity of the outer cylinder 10a away from the inner cylinder 10b or the tail pipe 44, the divided exhaust gas G2 flows in the vicinity of the outer cylinder 10a and is filled in the vicinity of the outer cylinder 10a. The sound absorption material 22 can be effectively used to reduce exhaust noise.

  In addition, an arc-shaped reinforcing portion 46 d that slightly bulges toward the downstream side is formed on the wall surface portion 46 a of the partition plate 46. The arc-shaped reinforcing portions 46d are respectively formed at the upper and lower positions across the central opening. The arc-shaped reinforcing portion 46d is provided to prevent the wall surface portion 46a from vibrating due to the shunted exhaust gas G2 flowing from the first silencing space 11 to the second silencing space 41 and generating abnormal noise. Therefore, the arc-shaped reinforcing portions 46d can be arranged at an appropriate location and number with respect to the wall surface portion 46a.

  As shown in FIG. 4, the downstream end 15 b of the outer cylinder 10 a, the tail cover 42, and the end cup 40 are integrally connected by a plurality of rivets 38. That is, a plurality of mounting holes 37 are also formed in the downstream end portion 15b of the outer cylinder 10a, and the mounting holes 37 formed in the upstream end portion 42b of the tail cover 42 and the flange portion 46c of the partition plate 46 are formed. The formed mounting holes 37 are aligned, and a rivet 38 is inserted through them to integrally connect and fix them. The tail pipe 44 is connected and fixed to each of the tail cover 42 and the partition plate 46 by welding or a sealant.

  Therefore, according to the above configuration of the end cup 40, the wall surface portion 42a and the downstream wall surface portion 42c of the tail cover 42, the upstream portion 44a and the downstream portion 44d of the tail pipe 44, and the wall surface portion 46a of the partition plate 46 are surrounded. A sealed second silencing space 41 is formed in the space. Further, an inner space 43 is formed in the inner portion of the upstream portion 44 a and the downstream portion 44 d of the tail pipe 44. The first silencing space 11 and the second silencing space 41 communicate with each other via a plurality of first communication holes 52, and the second silencing space 41 and the internal space 43 communicate with each other via two or more second communication holes 54. Communicate.

  Next, the operation and effect of the silencer 10 having the end cup 40 will be described.

  A part of the exhaust gas G introduced into the inner cylinder space 13 of the inner cylinder 10b through the exhaust pipe 20 serves as a diverted exhaust gas G2 through a large number of gas flow holes 12 and a pair of exhaust gas outlets 14 and notches 18. It flows into the first silencing space 11, and the remaining part goes straight through the inner cylinder space 13 of the inner cylinder 10b as the straight exhaust gas G1. The exhaust gas lead-out portion 14 and the cut-out portion 18 lead most of the exhaust gas G as the diverted exhaust gas G2 to the sound absorbing material 22, thereby reducing the exhaust noise.

  In the space from the upstream end 19a to the downstream end 19b of the inner cylinder 10b, the straight exhaust gas G1 and the shunt exhaust gas G2 pass through a number of gas flow holes 12 in the first silencing space 11 and the inner cylinder space 13. Exhaust noise is reduced by passing between them.

  Of the diverted exhaust gas G2 flowing into the first silencing space 11, the diverted exhaust gas G2 flowing downstream from the first silencing space 11 and in the vicinity of the outer cylinder 10a passes through the plurality of first communication holes 52 to form the second silencing space. 41 flows in. The shunt exhaust gas G <b> 2 that has flowed into the second silencing space 41 flows into the internal space 43 through the plurality of second communication holes 54. The diverted exhaust gas G2 flowing into the internal space 43 joins with the straight exhaust gas G1 flowing into the internal space 43 from the inner cylinder space 13. The combined exhaust gas G3 in which the straight exhaust gas G1 and the split exhaust gas G2 merge is discharged to the outside from the downstream outlet 50.

  Therefore, according to the silencer 10 according to the present invention, the exhaust gas G flowing in from the exhaust pipe 20 is prevented from flowing into the inner cylinder by providing a plurality of first communication holes 52 and second communication holes 54 in the end cup 40. The straight exhaust gas G1 flowing from the space 13 to the internal space 43, and the shunt exhaust gas flowing to the internal space 43 via the first silencing space 11, the plurality of first communication holes 52, the second silencing space 41, and the plurality of second communication holes 54. The gas G2 is shunted. The straight exhaust gas G1 that has entered the internal space 43 expands and loses energy by entering the second silencing space 41 through the second communication hole 54, and also due to a resonator (resonator) effect in the second silencing space 41. Exhaust noise is reduced. At the same time, the straight exhaust gas G1 that flows from the inner cylinder space 13 of the inner cylinder 10b to the inner space 43 of the tail pipe 44, the plurality of gas flow holes 12, the first silencing space 11, and the first communication hole 52 from the inner cylinder space 13 The shunting exhaust gas G2 entering the internal space 43 via the second silencing space 41 and the second communication hole 54 causes exhaust interference, thereby reducing exhaust noise. For example, in comparison with a conventional silencer that does not have a plurality of first communication holes 52 and second communication holes 54 in the end cup 40, exhaust sound near 2 kHz is reduced by about 5 dB by measuring the volume by the 2 mM AX method. I was able to confirm that. Also, the engine output did not decrease. And since only the 1st communicating hole 52 and the 2nd communicating hole 54 are formed in each of the partition plate 46 and the tail pipe 44 of the end cup 40, the structure is simple and can be manufactured at low cost. There is no increase.

  In addition, although the example which mounted the silencer 10 which concerns on this invention in the motorcycle 1 was shown as suitable embodiment, the silencer 10 which concerns on this invention is the engine of various vehicles, such as a tricycle and a four-wheeled vehicle. In addition, it can also be applied to portable and ground-mounted engines.

  In addition, although specific numerical values and materials have been shown and described, they can be appropriately changed without being limited to them. The exhaust noise reduction level can be adjusted by appropriately setting the number of the first communication holes 52 and the number of the second communication holes 54 and the positions and the hole diameters. Furthermore, various constituent elements can be added, changed, combined, or deleted without departing from the spirit of the present invention, and such elements are also included in the scope of the present invention.

1: motorcycle 10: silencer 10a: outer cylinder 10b: inner cylinder 11: first silencer space 12: gas flow hole 19a: upstream end 19b: downstream end 20: exhaust pipe 22: sound absorbing material 23: heat resistant Sound-absorbing material 30: holding member 38: rivet 40: end cup 41: second silencing space 42: tail cover 43: inner space 44: tail pipe 46: partition plate 52: first communication hole 54: second communication hole G: Exhaust gas

Claims (6)

An inner cylinder connected to the exhaust pipe;
An outer cylinder covering the inner cylinder;
A first silencing space formed between the outer cylinder and the inner cylinder and filled with a sound absorbing material;
A plurality of gas flow holes formed in the peripheral wall of the inner cylinder;
A silencer comprising: an end cup coupled to each of the downstream end portions of the outer cylinder and the inner cylinder,
The end cup includes a tail pipe connected to the downstream end of the inner cylinder, a partition plate connected to the downstream end of the outer cylinder and partitioning the downstream side of the first silencing space, and the outer cup. A cup-shaped tail cover coupled to the downstream end of the cylinder and covering the tail pipe; and a second silencing space formed between the tail pipe and the tail cover;
The partition plate has a plurality of first communication holes that communicate the first silencing space and the second silencing space,
The silencer, wherein the tailpipe has a plurality of second communication holes that communicate the inner space of the tailpipe and the second silencer space.   The silencer according to claim 1, wherein the first communication hole is formed at a position close to the outer cylinder.   The silencer according to claim 1 or 2, wherein the second communication hole is formed to extend in a substantially horizontal direction.   The upstream end portion and the downstream end portion of the tail pipe are connected and fixed to the inner peripheral end portion of the partition plate and the downstream end portion of the tail cover by welding or a sealing agent, respectively. The silencer according to any one of claims 1 to 3, wherein the silencer is characterized.   The silencer according to any one of claims 1 to 4, wherein a holding member is disposed between the outer peripheral surface of the inner cylinder and the sound absorbing material.   6. The silencer according to claim 1, wherein a heat-absorbing sound absorbing material is loaded on the outer cylinder side of the first silence space.

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