JP2018044444A - Engine exhaust muffler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably and simply mount a sound absorption material and its sound absorption material cover when a curve pipe is provided in a main body of a muffler and is formed of a pair of half-split pipes having flange parts.SOLUTION: A main muffler 2 comprises first and second exhaust lead-out pipes 4A, 4B constituting an exhaust path in a muffler space S and including a U-curved pipe 43, and upper and lower covers 53A, 53B covering an absorption material arranged on the outer periphery of the cuve pipe 43 and the absorption materia. The curve pipe 43 comprises a joint in which first and second half-split pipes 43A, 43B are jointed by a first spot welding part SP1 at an outer peripheral flange part 433 and an inner peripheral part 434. The upper and lower covers 53A, 53B have partial flanges 532, and are jointed by second spot welding part SP2 at projection parts 532A of the flanges.SELECTED DRAWING: Figure 10

Description

  The present invention relates to an exhaust silencer mounted on a vehicle equipped with an engine.

  Vehicles such as automobiles are provided with an exhaust silencer (muffler) in order to reduce engine exhaust noise. Generally, an exhaust silencer includes a silencer body that forms a silence space (expansion chamber), and an exhaust pipe that forms an exhaust path through which the exhaust passes in the silence space. The exhaust pipe includes an exhaust introduction pipe that introduces engine exhaust into the silencing space, and an exhaust outlet pipe that discharges the exhaust from the silencing space to the outside.

  It is known that increasing the length of the exhaust pipe in the silencer body is effective for reducing exhaust noise. Usually, the size of the silencer body is required to be as small as possible. In order to lengthen the pipe length in a limited silencing space, the exhaust pipe may be meandered. For example, Patent Literature 1 discloses an exhaust silencer in which a curved pipe curved in a U shape is incorporated in a part of the exhaust pipe. However, when the curved portion is formed, airflow noise due to the exhaust flow at that portion is likely to be generated. In order to effectively silence the exhaust pipe, it is desirable to attach a sound absorbing material such as glass wool to the exhaust pipe. For example, Patent Document 2 discloses an exhaust silencer in which a small hole is drilled in an exhaust pipe, the periphery thereof is surrounded by a sound absorbing material, and the sound absorbing material is covered with a sound absorbing material cover. The sound absorbing material cover is fixed to the exhaust pipe.

Japanese Utility Model Publication No. 62-21702 JP 2001-241315 A

  If the bending tube has a large bending radius, it can be formed by bending a steel tube or the like into a U shape. However, when the bending radius must be reduced for space saving or the like, bending molding becomes difficult. Therefore, the bending pipe is formed by joining a pair of half-cracked pipes having flange portions by spot welding. It is formed. In order to improve the silencing effect, it is desirable to provide the above-mentioned small hole and sound absorbing material in such a curved tube. In this case, how to attach the sound absorbing material cover to the bending tube becomes a problem.

  For example, it is conceivable that the sound absorbing material cover is provided with a flange portion so as to overlap the flange portion of the half cracked tube, and these flange portions are spot welded. However, when the sound absorbing material cover is attached to each half cracked tube, the flange portion of the half cracked tube is sandwiched between the flange portions of the pair of sound absorbing material covers, resulting in four-layer spot welding. End up. In this case, there is a concern about poor welding. On the other hand, although the method of wire-welding the edge part of a sound-absorbing material cover to the outer peripheral surface of a half-cracked tube is also considered, there exists a possibility that distortion may generate | occur | produce in a sound-absorbing material cover or a half-cracked tube (curved tube).

  An object of the present invention is to include a curved pipe as an exhaust pipe in a silencer main body, and when the curved pipe is formed of a pair of half cracked pipes having a flange portion, the curved pipe has a sound absorbing material and the sound absorbing material. An object of the present invention is to provide an engine exhaust silencer in which a cover can be securely and easily attached.

  An engine exhaust silencer according to an aspect of the present invention includes a silencer body that forms a silencer space into which engine exhaust is introduced, and an exhaust path through which the exhaust passes in the silencer space, and is at least U-shaped. An exhaust pipe including a curved pipe bent in a shape, a sound absorbing material disposed on an outer peripheral surface of the curved pipe, and a sound absorbing material cover covering the sound absorbing material, each of the curved pipes having a first flange portion. A pair of half-cracked pipes comprises a joined body joined at a predetermined first position in the overlapping portion of the first flange parts, and the sound absorbing material and the sound absorbing material cover are attached to at least one of the half cracked pipes. The sound absorbing material cover is provided and has a second flange portion joined to the first flange portion at a second position different from the first position, and the second flange portion is at least the first position. In positions other than There have shapes overlapping with the first flange portion.

  According to this exhaust silencer, since the bending tube is formed by a joined body of a pair of half-cracked tubes having the first flange portion, it is possible to cope with a small bending radius in response to a request for a compact silencer body. . The half cracked tubes are joined at the first position of the first flange portion, while the half cracked tube and the sound absorbing material cover are joined at the second position of the first flange portion and the second flange portion. Further, the second flange portion does not overlap the first flange portion at the first position. Therefore, both the half cracked tubes and both the half cracked tube and the sound absorbing material cover can take the form of overlapping joining of the two flange portions. For example, when spot welding is performed at the first position and the second position, two-layer spot welding can be used. For this reason, generation | occurrence | production of the welding defect and the distortion of a half crack pipe can be prevented.

  In the above exhaust silencer, the sound absorbing material cover includes an outer peripheral portion along an outer curved portion of the curved tube curved in a U shape, and an inner peripheral portion along an inner curved portion, and the second flange portion is It is desirable to extend along the outer peripheral portion, and the inner peripheral portion is provided with a line joint portion with respect to the outer peripheral surface of the half cracked tube.

  According to this exhaust silencer, the outer peripheral side of the sound absorbing material cover is fixed by joining the second flange portion to the first flange portion of the half cracked tube. On the other hand, the inner peripheral side is fixed to the outer peripheral surface of the half-cracked tube not by the flange portion but by the wire joint portion. When the bending radius of the bending tube is small, if a flange portion is formed on the inner peripheral side of the sound absorbing material cover in accordance with this, the moldability is deteriorated. For example, when a sound absorbing material cover is molded by drawing or the like, it is difficult to form a flange portion on the inner peripheral side having a small bending radius. On the other hand, since the length of the edge on the inner peripheral side is shorter than that on the outer peripheral side, it is possible to suppress the occurrence of distortion in the half-cracked tube even as a line joint. For this reason, by setting it as a wire junction part about an inner peripheral part side, the shape of a sound-absorbing material cover can be simplified and workability | operativity can be made favorable.

  In this case, each of the half cracked tubes includes, as the first flange portion, an outer peripheral flange portion along the outer curved portion and an inner peripheral flange portion along the inner curved portion, and these outer peripheral flange portion and inner peripheral flange portion. The pair of half cracked pipes are joined by spot welding at a portion, and the second flange portion of the sound absorbing material cover is a partial flange extending between the spot welding pitches in the outer peripheral flange portion, and the outer peripheral flange portion It is desirable that the partial flange and the partial flange are joined by spot welding, and the line joint portion is line welded to the outer peripheral surface of the half cracked tube at a position spaced from the inner peripheral flange portion.

  According to this exhaust silencer, the sound absorbing material cover can be fixed to the half-cracked tube using spot welding and wire welding. Moreover, since the 2nd flange part is equipped with the shape of the partial flange extended between the pitches of spot welding, the junction part of half crack pipes and the junction part of a half crack pipe and a sound-absorbing material cover are used as a 2nd flange. It can arrange | position with sufficient balance in the circumferential direction of a part.

  In the above exhaust silencer, the exhaust pipe further includes a set plate for supporting the curved pipe by the silencer body, and the exhaust pipe further includes a connection pipe having one end connected to an end of the curved pipe, The end portion of the bending tube is a non-flange portion where the first flange portion does not exist, the one end of the connection tube is inserted into the non-flange portion, and the non-flange portion is inserted into the set plate. It is desirable to provide a support opening and to support the non-flange portion into which the one end of the connection pipe is inserted.

  According to the exhaust silencer, by forming the non-flange portion at the end of the bending tube, a simple support structure for the bending tube can be realized by the set plate, and the connection tube is also supported by the set plate. be able to.

  In this case, it is preferable that the one end of the connection pipe is inserted to a position that reaches the first flange part beyond the non-flange part of the bending pipe.

  When the non-flange portion where the first flange portion does not exist is provided at the end of the bending tube, a slit corresponding to the thickness of the first flange portion is formed in the non-flange portion at the facing portion between the half cracked tubes. End up. When exhaust gas leaks from this slit, airflow noise can be generated. However, by inserting one end of the connecting pipe to the position where it reaches the first flange portion, the air leakage passage from the slit is blocked, so that the generation of the airflow noise can be prevented.

  In the exhaust silencer, the exhaust pipe includes an exhaust introduction pipe that introduces engine exhaust into the silencing space, and an exhaust outlet pipe that discharges the exhaust to the outside from the silencing space. It is desirable that a part of the exhaust lead-out pipe is configured in the silencing space.

  According to this exhaust silencer, since the curved pipe is incorporated in the exhaust outlet pipe having a relatively high degree of freedom in setting the exhaust path, the degree of freedom in design can be increased.

  According to the present invention, in an exhaust silencer for an engine, which includes a curved pipe as an exhaust pipe in the silencer body, and the curved pipe is formed of a pair of half-cracked pipes having a flange portion, poor connection, distortion, etc. It is possible to provide a structure that allows the sound absorbing material and the sound absorbing material cover to be securely and easily attached to the bending tube without generating the sound absorbing material.

FIG. 1 is a schematic diagram of an exhaust system of a vehicle to which an engine exhaust silencer according to the present invention is applied. FIG. 2 is a top view of the main silencer (exhaust silencer) according to the embodiment of the present invention with the upper plate removed. 3 is a cross-sectional view taken along line III-III in FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 5 is a perspective view of the bending tube. FIG. 6 is an enlarged perspective view of a main part of FIG. FIG. 7 is a perspective view of the bending tube with a sound absorbing material cover attached. FIG. 8 is a perspective view of a state where a connecting pipe is further attached to the bending pipe shown in FIG. FIG. 9 is a perspective view of a state where a set plate is further attached to the bending tube shown in FIG. FIG. 10 is a top view for explaining a joining mode of the bending tube and the sound absorbing material cover.

[Vehicle exhaust system]
Hereinafter, an engine exhaust silencer according to an embodiment of the present invention will be described in detail with reference to the drawings. First, an exhaust system of a vehicle on which the exhaust silencer is mounted will be schematically described with reference to FIG. In FIG. 1 and other drawings, front / rear, left / right and up / down direction indications are attached. These directions are relative to the vehicle. That is, the front-rear, left-right, and up-down directions used in the following description are perpendicular to the front-rear direction (vehicle front-rear direction), left-right direction (vehicle width direction) shown in FIG. The direction is the same as the vertical direction. Further, when referring to upstream and downstream, the flow direction of the exhaust is used as a reference.

  The vehicle is, for example, a four-wheeled vehicle, and includes an engine 1 and an exhaust device 10 that constitutes an exhaust system of the engine 1. The engine 1 is, for example, an in-line four-cylinder turbocharged gasoline engine, and is installed horizontally in the engine compartment in front of the vehicle compartment, that is, with the cylinders arranged in the vehicle width direction. The exhaust device 10 is connected to the engine 1 and extends rearward along the lower surface of the vehicle.

  The exhaust device 10 includes an exhaust manifold 11, a turbocharger 12, an exhaust pipe 13, a first catalyst device 14, a second catalyst device 15, a pre-silencer 16, and a main silencer 2 (exhaust silencer). . The exhaust manifold 11 has a branch end connected to an exhaust port of each cylinder head of the engine 1 on the upstream side, and an exhaust passage having a collective end on the downstream side for collecting exhaust discharged from these exhaust ports into one flow path. Is provided inside. The turbocharger 12 is connected to the collective end of the exhaust manifold 11 and supercharges the intake air of the engine 1 using the energy of the exhaust discharged from the engine 1.

  The exhaust pipe line 13 is a pipe line serving as an exhaust passage, and is connected to the downstream end of the turbocharger 12 and extends rearward. A first catalyst device 14, a second catalyst device 15, and a pre-silencer device 16 are incorporated in the exhaust pipe line 13 in order from the upstream side, and the main silencer device 2 is connected to the end. The first and second catalytic devices 14 and 15 purify harmful components in the exhaust discharged from the engine 1, for example, a catalyst including a NOx storage reduction catalyst that temporarily stores NOx in the exhaust and then reduces it. It is comprised from the main body and the casing which accommodates this catalyst main body.

  The pre-silencer 16 and the main silencer 2 are incorporated in the exhaust system of the engine 1 to reduce exhaust noise. Of these silencers 16 and 2, the pre-muffler 16 disposed on the upstream side mainly has a function of reducing high-frequency components in the exhaust noise. The pre-silencer 16 can employ, for example, a sound-absorption-type silencer, and is filled between a porous inner cylinder pipe through which exhaust passes, an outer cylinder pipe covering the porous inner cylinder pipe, and the inner cylinder pipe and the outer cylinder pipe Sound absorbing material such as glass wool. On the other hand, the main silencer 2 mainly has a function of reducing low and medium frequency components in the exhaust noise. Hereinafter, the structure of the main silencer 2 will be described in detail.

[Overall structure of main silencer]
2 is a top view of the main silencer 2 (with an upper plate 20A described later removed), FIG. 3 is a sectional view taken along line III-III in FIG. 2, and FIG. 4 is a sectional view taken along line IV-IV in FIG. It is. The main silencer 2 is disposed below the rear floor at the rear end of the vehicle, and includes a silencer body 20, an exhaust introduction pipe 3 (exhaust pipe), a first exhaust outlet pipe 4A, and a second exhaust outlet pipe 4B (exhaust pipe).

  The silencer body 20 is a housing that forms a silencing space S (expansion chamber) into which exhaust of the engine 1 is introduced. The silencer body 20 has a relatively short shape in the front-rear direction and a relatively long shape in the left-right direction, that is, a shape that is long in the vehicle width direction and flat in the up-down direction, and has a rounded rectangular shape as a whole. . Thereby, the silencing space S in the silencer body 20 is also a long and flat space in the vehicle width direction.

  The silencer body 20 includes a front wall 21 and a rear wall 22 aligned in the front-rear direction of the vehicle, a right wall 23 and a left wall 24 aligned in the left-right direction (vehicle width direction), and a vertical direction An upper wall 25 and a lower wall 26 arranged in the (vehicle height direction) are provided. The front wall 21 is a wall that extends linearly in the left-right direction. The rear wall 22 is a wall that is curved so as to have a gentle convex shape toward the rear in a top view and extends in the left-right direction. The right wall 23 and the left wall 24 are short walls extending linearly in the front-rear direction, and connect the front wall 21 and the rear wall 22 on the right end side and the left end side, respectively. As shown in FIGS. 3 and 4, the left wall 24 has a substantially semicircular curved shape in the left-right cross-sectional view (the same applies to the right wall 23). The upper wall 25 is a wall that seals the upper surface of the space surrounded by the side walls including the front wall 21, the rear wall 22, the right wall 23, and the left wall 24, and the lower wall 26 is a wall that seals the lower surface of the side wall. is there.

  The silencer body 20 is a joined body of an upper plate 20A and a bottom plate 20B, which is a half-cracked housing divided in the vertical direction. The upper plate 20A is a half-cracked housing having a cavity bulging upward, and has an upper flange portion 201 on the outer periphery of the lower edge thereof. The bottom plate 20B is a half-cracked housing having a cavity that bulges downward, and has a lower flange portion 202 on the outer periphery of its upper edge.

  The upper plate 20A forms the upper wall 25 and the upper half of the side wall, and the bottom plate 20B forms the lower wall 26 and the lower half of the side wall. The upper flange portion 201 and the lower flange portion 202 are overlaid and joined together so that the upper plate 20A and the bottom plate 20B are integrated, and the silencer body 20 having the silencing space S is formed. The upper wall 25 of the upper plate 20A and the lower wall 26 of the bottom plate 20B are provided with a plurality of beads 203 extending in the front-rear direction. The bead 203 is a groove-shaped portion that protrudes toward the silencing space S, and is provided for the purpose of increasing the rigidity of the silencer body 20.

  The exhaust introduction pipe 3, the first exhaust lead-out pipe 4 </ b> A, and the second exhaust lead-out pipe 4 </ b> B are exhaust pipes that constitute an exhaust path through which the exhaust passes in the silencing space S. That is, the pipe is arranged to flow the exhaust gas along a desired path in a closed space called the silencing space S. The exhaust introduction pipe 3, the first exhaust lead-out pipe 4A, and the second exhaust lead-out pipe 4B are pipes separated from each other. The exhaust introduction pipe 3 has an exhaust outlet A through which exhaust is blown out to the silencing space S. On the other hand, the first and second exhaust outlet pipes 4A and 4B each have a first exhaust inlet B1 and a second exhaust inlet B2 for taking in the exhaust in the silencing space S. Exhaust gas discharged from the exhaust outlet A enters the silencing space S, expands, and is then taken into the first and second exhaust inlets B1 and B2, and is discharged to the outside through the first and second outlet openings C1 and C2, respectively. Is done.

  The exhaust introduction pipe 3 is a linear hollow circular pipe that introduces exhaust of the engine 1 into the silencing space S. A relay pipe 31 is inserted on the upstream side of the exhaust introduction pipe 3. The upstream end of the relay pipe 31 is connected to the downstream end of the exhaust pipe 13. The downstream end of the exhaust introduction pipe 3 is the exhaust outlet A described above. The exhaust outlet A faces the rear wall 22.

  The exhaust introduction pipe 3 passes through the front wall 21 in the vicinity of the center in the left-right direction, and is disposed in the silence space S so that the exhaust outlet A approaches the rear wall 22. That is, as shown in FIG. 2, the exhaust introduction pipe 3 is silenced from the front wall 21 side so that the exhaust outlet A is disposed closer to the rear wall 22 than the center of the silencer body 20 in the front-rear direction. It is inserted toward the space S. In the present embodiment, a later-described rectifying plate 6 is disposed between the exhaust outlet A and the rear wall 22. In another embodiment in which the current plate 6 is not used, the exhaust outlet A may be closer to the rear wall 22.

  The exhaust introduction pipe 3 is supported by a recess for receiving a pipe provided at the center in the left-right direction of the front wall 21 of the bottom plate 20B. Further, the vicinity of the exhaust outlet A of the exhaust introduction pipe 3 is supported by the support plate 32. The support plate 32 is a sheet metal member provided with a support hole that penetrates and supports the exhaust introduction pipe 3. The upper end side of the support plate 32 is fixed to the upper wall 25, and the lower end side is fixed to the lower wall 26. The exhaust introduction pipe 3 is attached to the silencer body 20 so as to rise rearward so that the exhaust outlet A faces slightly upward. This is because moisture (condensed water) in the exhaust gas condensed in the silencing space S may stay on the lower wall 26, and the retained water does not flow back to the exhaust introduction pipe 3 through the exhaust outlet A. It is.

  The first exhaust lead-out pipe 4A and the second exhaust lead-out pipe 4B are pipes for discharging the exhaust from the sound deadening space to the outside. The first and second exhaust lead-out pipes 4A and 4B have the same components, and are arranged in the silencing space S symmetrically to the left and right of the exhaust introduction pipe 3. Each of the first and second exhaust outlet pipes 4A and 4B includes a first straight pipe 41 (connection pipe), a second straight pipe 42 (connection pipe), and a curved pipe 43. The curved tube 43 is a tube curved in a U shape. The first straight tube 41 and the second straight tube 42 extend from both ends of the bending tube 43 in parallel in the left-right direction. FIG. 5 shows a perspective view of a single unit of the bending tube 43.

  In the exhaust flow of the first and second exhaust lead-out pipes 4A and 4B, the first straight pipe 41 is an exhaust pipe disposed on the upstream side of the second straight pipe. The first straight pipe 41 is arranged so as to be adjacent to the front wall 21 extending linearly. That is, the distance in the front-rear direction between the front side portion of the first straight tube 41 and the front wall 21 is narrow. On the other hand, the second straight tube 42 is disposed at a substantially central position in the front-rear direction of the sound deadening space S, which is separated from the front wall 21 and also from the rear wall 22. The height positions in the vertical direction of the first straight tube 41 and the second straight tube 42 are substantially the same. The bending tube 43 connects the first and second straight tubes 41 and 42 to each other.

  FIG. 3 shows a cross section in the left-right direction of the first straight pipe 41 of the second exhaust lead-out pipe 4B. The first straight tube 41 is a tube having a circular cross section that extends linearly in the left-right direction, and includes an upstream end 411 and a downstream end 412. The upstream end 411 is a pipe end provided with an opening that becomes the above-described second exhaust inlet B2 (in the case of the first straight pipe 41 of the first exhaust outlet pipe 4A, the first exhaust inlet B1). The upstream end 411 is processed to increase the inner diameter in a bell mouth shape so that the exhaust gas can be smoothly taken into the second exhaust inlet B2. The downstream end 412 is a tube end portion that is inserted into the upstream end 431 of the bending tube 43.

  As described above, the exhaust outlet A is disposed in the vicinity of the rear wall 22 (in the present embodiment, in the vicinity of the rectifying plate 6 substantially corresponding to the rear wall 22), whereas the first and second The exhaust inlets B <b> 1 and B <b> 2 are disposed in the vicinity of the front wall 21 because the first straight pipe 41 is adjacent to the front wall 21. Further, the exhaust outlet A is disposed at a central position in the left-right direction, whereas the first and second exhaust inlets B1 and B2 are disposed on the right end side and the left end side of the front wall 21, respectively. Specifically, the first exhaust inlet B1 faces the right wall 23 near the front wall 21, the second exhaust inlet B2 faces the left wall 24 near the front wall 21, and is close to the right wall 23 and the left wall 24, respectively. Placed in position. In this way, by separating the exhaust outlet A from the first and second exhaust inlets B1 and B2, the exhaust noise of the exhaust introduction pipe 3 is hardly transmitted to the first and second exhaust lead-out pipes 4A and 4B. Yes.

  The second straight tube 42 is a tube having a circular cross section that extends linearly in the left-right direction, and is a tube having a longer left-right width than the first straight tube 41. The upstream end of the second straight tube 42 is inserted into the downstream end 432 of the bending tube 43. The downstream end of the second straight pipe 42 of the first exhaust outlet pipe 4A passes through the right wall 23. A first tail pipe 44A is connected to the penetrated downstream end. Further, the downstream end of the second straight pipe 42 of the second exhaust outlet pipe 4 </ b> B penetrates the left wall 24. A second tail pipe 44B is connected to the penetrated downstream end. The downstream end of the first tail pipe 44A is a first outlet opening C1, and the downstream end of the second tail pipe 44B is a second outlet opening C2. Exhaust gas is discharged to the outside through the first and second outlet openings C1 and C2.

  Referring to FIG. 5, the curved pipe 43 is a pipe that forms an exhaust path that is substantially circular in cross section and curved in a U shape. As described above, the bending tube 43 includes the upstream end 431 to which the first straight tube 41 is connected and the downstream end 432 to which the second straight tube 42 is connected. The curved tube 43 is composed of a joined body of a first half-cracked tube 43A and a second half-cracked tube 43B that are half-cracked tubes divided in the vertical direction. 43 A of 1st half crack pipes and 43 B of 2nd half crack pipes are mutually joined by the outer peripheral flange part 433 and the inner peripheral flange part 434. FIG. The outer peripheral flange portion 433 extends outward from the outer curved portion L1 of the curved tube 43 curved in a U shape. On the other hand, the inner peripheral flange portion 434 extends inward from the inner curved portion L2 so as to fill a U-shaped space defined by the inner curved portion L2 of the curved tube 43.

  The first half-cracked tube 43A has a semicircular cross section that bulges upward, has a U-shaped cavity in bottom view, and forms an upper flange portion 433A (first flange portion) that forms the upper side of the outer peripheral flange portion 433. On the outer peripheral side, and an upper flange portion 434A that forms the upper side of the inner peripheral flange portion 434 on the inner peripheral side. The second half-cracked tube 43B has a semicircular section bulging downward and has a U-shaped cavity in a top view, and forms a lower flange portion 433B (first flange) forming the lower side of the outer peripheral flange portion 433. Part) on the outer peripheral side and a lower flange part 434B forming the lower side of the inner peripheral flange part 434 on the inner peripheral side. The upper flange portion 433A and the lower flange portion 433B, and the upper flange portion 434A and the lower flange portion 434B are vertically overlapped and joined, whereby the bending tube 43 is formed.

  As shown in FIGS. 2 and 3, the bending tube 43 is supported by the silencer body 20 by the set plate 27. The set plate 27 is a flat plate member extending in the vertical direction, and has an upper flange portion 271 at the upper end side, a lower flange portion 272 at the lower end side, and two burring portions 273 at the center. In each burring portion 273, the upstream end 431 (downstream end 432) of the bending tube 43 is densely inserted. The upper flange portion 271 is joined to the upper wall 25, and the lower flange portion 272 is joined to the lower wall 26. The upper wall 25 is provided with a welding hole 204 (FIG. 4), and the upper flange portion 271 is fixed to the upper wall 25 by plug welding. The lower flange portion 272 is fixed to the lower wall 26 by spot welding.

  The main silencer 2 includes a first silencer 51 applied to the first straight tube 41, a second silencer 52 applied to the second straight tube 42, and a curved silencer 53 applied to the curved tube 43. Is provided. These silencers 51 to 53 include a large number of small holes drilled in each tube wall, a sound absorbing material that covers the outer periphery of the tube wall portion having these small holes, and a sound absorbing material cover that covers the periphery of the sound absorbing material. Consists of. When airflow sound (exhaust noise) is generated in the exhaust gas passing through the first and second exhaust lead-out pipes 4A and 4B, the airflow sound is released outside the pipe through the small holes and is absorbed by the sound absorbing material.

  The first silencer 51 is attached so as to cover a part of the circumferential direction in a predetermined region of the first straight tube 41 in the tube axis direction. Specifically, the first silencer 51 is provided only on the tube wall portion (rear side portion) that substantially faces the second straight tube 42 in the entire circumference of the first straight tube 41. That is, a large number of small holes 413 (FIG. 8) are perforated in the opposing tube wall portions, the sound absorbing material is disposed on the outer periphery of the tube wall portion having the small holes, and the sound absorbing material is covered so as to cover the sound absorbing material. A cover is attached to the outer peripheral surface of the first straight tube 41. As described above, such a partial arrangement has a small space in the front-rear direction between the front side portion of the first straight tube 41 and the front wall 21 and a space for arranging the sound absorbing material and the sound absorbing material cover. This is because it cannot be secured.

  The second silencer 52 is attached so as to cover the entire circumference in a predetermined region of the second straight tube 42 in the tube axis direction. Specifically, in the predetermined region, the second muffler 52 has the numerous small holes perforated over the entire circumference of the tube wall of the second straight tube 42, and the entire circumference of the tube wall having the small holes. The sound absorbing material is arranged so as to cover, and a cylindrical sound absorbing material cover capable of covering the sound absorbing material is attached to the outer peripheral surface of the second straight tube 42. In addition, in order to improve rigidity, the sound absorbing material covers of the first silencer 51 and the second silencer 52 are connected by a connecting member 54.

  As shown in FIGS. 3 and 4, the curved silencer 53 includes a large number of small holes 43H drilled in the vicinity of the bulging tops of the first half cracked tube 43A and the second half cracked tube 43B, and the small holes 43H. The sound-absorbing material 7 that covers the outer peripheral surfaces of the first and second half-broken tubes 43A and 43B, and the upper cover 53A and the lower cover 53B (sound-absorbing material cover) that respectively cover the sound absorbing materials 7 are provided. The sound absorbing material 7 is, for example, glass wool. The curved silencer 53 will be described in detail later.

  The rectifying plate 6 is disposed at a position facing the exhaust outlet A, and includes a guide surface that guides exhaust from the exhaust outlet A toward the rear wall 22 in the left-right direction (both sides in the vehicle width direction). The rectifying plate 6 includes a tip portion that faces the central portion in the left-right direction of the exhaust outlet A, and the guide surface extends from the tip portion to the left and right rear. Exhaust gas blown out from the exhaust outlet A is diverted at the tip, and travels left and right along the left and right guide surfaces and the rear wall 22. Exhaust air that has been split to the left and right blows to the right wall 23 and the left wall 24, and the corners of the rear wall 22, the right wall 23, and the left wall 24 are rounded, It goes forward along the wall 23 and the left wall 24. Thereafter, the exhaust enters the first and second exhaust inlets B1 and B2 and passes through the first and second exhaust outlet pipes 4A and 4B.

  The rectifying plate 6 is supported by the upper wall 25 and the lower wall 26 of the silencer body 20. That is, a flange portion 61 is provided on the upper end side of the rectifying plate 6, and the flange portion 61 is fixed to the upper wall 25 by plug welding. On the other hand, the lower end side of the current plate 6 is attached to the lower wall 26 via the attachment plate 28. The mounting plate 28 extends in the left-right direction across the bead 203 and provides a seating surface for the rectifying plate 6. The flange portion on the lower end side of the rectifying plate 6 is fixed to the mounting plate 28 by spot welding, and the mounting plate 28 is fixed to the lower wall 26 by spot welding.

[Details of bending tube and bending silencer]
Hereinafter, the bending tube 43 and the bending silencer 53 will be described in detail. As described above with reference to FIG. 5, the bending tube 43 is formed by joining the first half-cracked tube 43 </ b> A and the second half-cracked tube 43 </ b> B by the outer peripheral flange portion 433 and the inner peripheral flange portion 434. FIG. 6 is an enlarged perspective view of a main part VI surrounded by a one-dot chain line in FIG. FIG. 7 is a perspective view of the bending tube 43 with the sound absorbing material cover attached. FIG. 7 mainly shows a state in which the upper cover 53A as the sound absorbing material cover is attached to the first half-break pipe 43A. FIG. 8 is a perspective view of a state in which the first straight tube 41 and the second straight tube 42 are further attached to the bending tube 43 shown in FIG. The first straight tube 41 to which the first silencer 51 is attached is at the upstream end 431 (end portion) of the bending tube 43, and the second straight tube 42 to which the second silencer 52 is attached is downstream of the bending tube 43. Each end is connected to an end 432 (end). FIG. 9 is a perspective view of a state in which the set plate 27 is further attached to the bending tube 43 shown in FIG.

  Referring to FIG. 5, the bending tube 43 includes a non-flange portion 435 at each of an upstream end 431 and a downstream end 432. The non-flange portion 435 is a cylindrical portion where the outer peripheral flange portion 433 and the inner peripheral flange portion 434 do not exist in the bending tube 43. As shown in FIG. 6, the upper flange portion 433A and the lower flange portion 433B constituting the outer peripheral flange portion 433 are bent portions along the outer curved portion L1 of the first half-cracked tube 43A and the second half-cracked tube 43B, respectively. It is. The flange edge 433E of the outer peripheral flange portion 433 is located at a position where it enters the pipe by a predetermined length from the upstream end 431 (downstream end 432). A protruding portion from the flange end edge 433E to the upstream end 431 is a non-flange portion 435.

  Since the outer peripheral flange portion 433 does not exist, the non-flange portion 435 has a slit SL having an opening width corresponding to the thickness of the upper flange portion 433A and the lower flange portion 433B and the bending allowance thereof. That is, in the abutting surfaces of the first and second half cracked tubes 43A and 43B in the non-flange portion 435, the upper facing surface 435A of the first half cracked tube 43A and the lower facing surface 435B of the second half cracked tube 43B are formed. , Facing the opening width. A similar slit SL also exists on the inner peripheral flange portion 434 side.

  As shown in FIG. 3, the downstream end 412 of the first straight pipe 41 is inserted into the non-flange portion 435. Although not shown, the upstream end of the second straight pipe 42 is also inserted into the non-flange portion 435 on the downstream end 432 side. Further, the non-flange portion 435 is inserted through an opening provided with a burring portion 273 (support opening) of the set plate 27. That is, the burring portion 273 supports the non-flange portion 435 into which one ends of the first and second straight pipes 41 and 42 are inserted. In this way, by forming the non-flange portion 435, a simple support structure of the bending tube 43, that is, a structure in which the bending tube 43 is supported by the set plate 27 including the burring portion 273 having a simple round hole is realized. In addition, the first and second straight tubes 41 and 42 can also be supported by the set plate 27.

  Here, the downstream end 412 of the first straight pipe 41 is inserted into the bending pipe 43 to a position that reaches the outer peripheral flange part 433 beyond the non-flange part 435. In FIG. 6, the position of the downstream end 412 of the downstream end 412 of the first straight pipe 41 is indicated by a one-dot chain line. The downstream end 412 is inserted from the upstream end 431 of the bending tube 43 to the far side of the flange end edge 433E of the outer peripheral flange portion 433. Similarly, the upstream end of the second straight pipe 42 is inserted to a position that reaches the outer peripheral flange portion 433.

  In the non-flange portion 435, the slit SL is formed at the facing portion between the first and second half-cracked tubes 43A and 43B as described above. When the exhaust gas leaks from the slit SL, airflow noise can be generated. However, by inserting one end of each of the first and second straight pipes 41 and 42 to a position reaching the outer peripheral flange portion 433, the air leakage passage from the slit SL is blocked. For this reason, generation | occurrence | production of the said airflow sound can be prevented.

  Next, the bending silencer 53 will be described in detail with reference mainly to FIGS. 3, 4 and 7. The curved silencer 53 includes a sound absorbing material 7 attached to the outer peripheral surfaces of the first and second half-broken tubes 43A and 43B, and an upper cover 53A and a lower cover 53B that cover the sound absorbing material 7, respectively. The sound absorbing material 7 is arranged along the substantially entire region of the outer peripheral surface of the bulging portion of the first and second half cracked tubes 43A and 43B in the portion excluding the non-flange portion 435 of the bending tube 43. A small hole 43H drilled near the top of the bulging portion is completely covered with the sound absorbing material 7. The upper cover 53A covers the sound absorbing material 7 on the outer periphery of the first half cracked tube 43A, and the lower cover 53B covers the sound absorbing material 7 on the outer periphery of the second half cracked tube 43B.

  The upper cover 53A and the lower cover 53B are substantially U-shaped half-cracked members including a cover main body portion 531, a partial flange 532 (second flange portion), a wire joint portion 533, an upstream end 534, and a downstream end 535. is there. The cover main body portion 531 is a portion that actually covers the sound absorbing material 7, and faces the outer peripheral surface of the bulging portion of the first and second half cracked tubes 43 </ b> A and 43 </ b> B via the accommodation space of the sound absorbing material 7. ing. The upper cover 53A and the lower cover 53B include an outer peripheral portion L3 along the outer curved portion L1 of the curved tube 43 curved in a U shape, and an inner peripheral portion L4 along the inner curved portion L2.

  The partial flanges 532 are portions that extend outward along the outer peripheral portion L3 and overlap and join the upper flange portion 433A and the lower flange portion 433B of the bending tube 43 in the vertical direction. Each of the line joint portions 533 is located in the vicinity of the inner peripheral portion L4 and is a portion that is joined to the outer peripheral surfaces of the first and second half cracked tubes 43A and 43B. The upstream end 534 is in the vicinity of the upstream end 431 of the bending tube 43, and the downstream end 535 is in the vicinity of the downstream end 432 of the bending tube 43 on the outer peripheral surface of the bulging portion of the first and second half cracked tubes 43A and 43B, respectively. It is a curved part that touches.

  The partial flange 532 does not have a substantially uniform extending length (extending length from the curved center of the U-shaped curve to the outside in the radial direction) over the entire length of the outer peripheral portion L3, but the protruding portion 532A. And a regression unit 532B. The extending length of the protruding portion 532A is substantially the same as the upper and lower flange portions 433A and 433B. On the other hand, the extending length of the retreating part 532B is about half or 1/5 of the upper and lower flange parts 433A, 433B. The partial flange 532 has a shape in which such protruding portions 532A and retreating portions 532B are alternately formed along the outer peripheral portion L3.

  On the other hand, in the upper and lower flange portions 433A and 433B (outer peripheral flange portion 433), there are no portions that are intentionally extended and shortened in length, such as the retracting portion 532B. Therefore, as shown in FIG. 7, when the partial flange 532 of the upper cover 53A and the upper flange portion 433A of the first half-cracked tube 43A are overlapped in the vertical direction, they do not completely overlap, and the retreat portion 532B The upper flange portion 433A is exposed. The relationship between the partial flange 532 of the lower cover 53B and the lower flange portion 433B of the second half cracked tube 43B is the same.

  The upper flange portion 433A and the lower flange portion 433B of the bending tube 43 are joined by spot welding of two sheets. In addition, the partial flange 532 of the upper cover 53A and the upper flange portion 433A of the first half-cracked tube 43A, and the partial flange 532 of the lower cover 53B and the lower flange portion 433B of the second half-cracked tube 43B are also two spots. Joined by welding. That is, in the outer peripheral flange portion 433, although the upper and lower flange portions 433A and 433B and the upper and lower partial flanges 532 overlap each other, the respective joints are made by two-layer spot welding.

  That is, the upper and lower flange portions 433A and 433B and the partial flanges 532 are joined by spot welding at positions (second positions) where the protruding portions 532A and the upper and lower flange portions 433A and 433B overlap each other. On the other hand, the upper and lower flange portions 433A and 433B are joined by spot welding at the portion (first position) where the upper and lower flange portions 433A and 433B are exposed due to the formation of the retreating portion 532B.

  On the other hand, on the side of the inner peripheral portion L4 of the upper and lower covers 53A and 53B, the form of flange joining as in the outer peripheral portion L3 side is not taken. That is, the flange portion is not extended from the inner peripheral portion L4, and the edge portion of the inner peripheral portion L4 is joined to the outer peripheral surfaces of the upper and lower covers 53A and 53B by wire welding. 4). This is because the formability of the upper and lower covers 53A and 53B deteriorates if a flange portion is provided on the inner peripheral side curved in a U-shape.

  FIG. 10 is a top view for explaining an example of a joining mode between the bending tube 43 and the upper cover 53A (lower cover 53B). The outer peripheral flange portion 433, that is, the overlapping portion of the upper flange portion 433A and the lower flange portion 433B is formed at a plurality of positions (first positions) arranged at a predetermined pitch along the circumferential direction of the outer peripheral portion L3. Joined at part SP1. On the other hand, the upper flange portion 433A and the partial flange 532 have a second spot weld portion SP2 formed at a plurality of positions (second positions) different from the formation position of the first spot weld portion SP1 in the circumferential direction of the outer peripheral portion L3. It is joined with. The same applies to the lower flange portion 433B and the partial flange 532.

  Specifically, the protruding portion 532A of the partial flange 532 is formed to extend between the pitches of the first spot welds SP1 in the outer peripheral flange portion 433. In other words, the partial flange 532 has a shape that overlaps with the upper flange portion 433A at a position excluding the position where the first spot weld portion SP1 is formed. In the protruding portion 532A, the upper flange portion 433A (outer peripheral flange portion) and the partial flange 532 are joined by the second spot weld portion SP2. Thereby, 1st spot welding part SP1 and 2nd spot welding part SP2 are arrange | positioned substantially equally in the circumferential direction of the outer peripheral part L3.

  The first spot welded portion SP1 is also disposed at a predetermined position of the inner peripheral flange portion 434 (upper flange portion 434A and lower flange portion 434B). The line joint portion 533 of the upper cover 53A is line-welded to the outer peripheral surface of the first half-cracked tube 43A at a position separated from the inner peripheral flange portion 434 in the axial direction of the tube.

  Subsequently, an example of an assembly procedure of the first and second exhaust outlet pipes 4A and 4B will be described. The upper cover 53A is attached in a state where the sound-absorbing material 7 is sandwiched between the first half-cracked tube 43A in advance. The attachment location is the second spot welded portion SP2 in the protruding portion 532A on the outer peripheral portion L3 side, and the line joint portion 533 on the inner peripheral portion L4 side. Similarly, the sound absorbing material 7 and the lower cover 53B are attached to the second half cracked tube 43B in advance. And a pair of half cracked pipes 43A and 43B are joined by 1st spot welding part SP1 in the outer peripheral flange part 433 and the inner peripheral flange part 434. FIG. Thereby, the assembly of the bending tube 43 and the upper and lower covers 53A and 53B shown in FIG. 7 is created.

  Next, the burring portion 273 of the set plate 27 is fitted into the non-flange portion 435 provided at the upstream end 431 and the downstream end 432 of the bending tube 43. Thereafter, the first straight pipe 41 with the first silencer 51 assembled in advance is inserted into the upstream end 431, and the second straight pipe 42 with the second silencer 52 assembled in advance is inserted into the downstream end 432. As described above, this insertion is an insertion having a depth that fills the slit SL of the non-flange portion 435. Thereby, the assembly shown in FIG. 9 is created. Thereafter, the first silencer 51 and the second silencer 52 are connected by the connecting member 54, and then the assembly is assembled to the silencer body 20.

[Effects]
According to the main silencer 2 described above, the following operational effects are obtained. Since the bending tube 43 is formed by a joined body of the first half-cracked tube 43A having the upper flange portions 433A and 434A and the second half-cracked tube 43B having the lower flange portions 433B and 434B, the silencer body 20 In response to the demand for compactness, it can also handle small bending radii. The first half cracked tube 43A and the second half cracked tube 43B are an upper flange portion 433A and a lower flange portion 433B (outer peripheral flange portion 433) on the outer curved portion L1 side, and an upper flange portion 434A and a lower portion on the inner curved portion L2 side. The flange portions 434B (inner peripheral flange portions 434) are joined at predetermined positions by the first spot welds SP1.

  On the other hand, the upper and lower covers 53A and 53B as the sound absorbing material cover have a partial flange 532 on the outer peripheral portion L3 side. The first half cracked tube 43A and the upper cover 53A are joined by the second spot welded portion SP2 at the overlapping portion of the upper flange portion 433A and the protruding portion 532A of the partial flange 532. The partial flange 532 has a retreating part 532B at the position where the first spot welding part SP1 is formed, and does not overlap with the upper flange part 433A. The same applies to the second half cracked tube 43B and the lower cover 53B. Therefore, the joint part (first spot welded part SP1) between the half cracked pipes 43A and 43B and the joined part (second spot welded part SP2) between the half cracked pipes 43A and 43B and the upper and lower covers 53A and 53B. Both can be spot-welded with two sheets. For this reason, generation | occurrence | production of the welding defect and the distortion of a half crack pipe can be prevented.

  The upper and lower covers 53A and 53B include an outer peripheral portion L3 along the outer curved portion L1 of the curved tube 43 curved in a U-shape and an inner peripheral portion L4 along the inner curved portion L2, and the partial flange 532 has an outer peripheral portion. The inner circumferential portion L4 is provided with a line joint portion 533 with respect to the outer circumferential surface of the bending tube 43, extending along L3. That is, on the outer peripheral portion L3 side, the above-described flange joint using the partial flange 532 is used, whereas on the inner peripheral portion L4 side, the curved tube 43 is not formed by the flange portion but by the wire joint portion 533 where wire welding is performed. It is being fixed to the outer peripheral surface.

  If it is necessary to reduce the bending radius of the bending tube 43 under the demand for compactness, if the flange portion is formed on the inner peripheral portion L4 side of the upper and lower covers 53A and 53B in accordance with this, the moldability is poor. Become. For example, when the upper and lower covers 53A and 53B are formed by drawing or the like, it is difficult to form a flange portion on the inner peripheral portion L4 side having a small bending radius. On the other hand, since the length of the edge on the inner peripheral portion L4 side is shorter than that on the outer peripheral portion L3 side, the occurrence of distortion in the first and second half cracked tubes 43A and 43B is suppressed even if wire welding is employed. it can. For this reason, the shape of the upper and lower covers 53A and 53B can be simplified and the workability can be improved by setting the inner peripheral portion L4 side to the line connecting portion 533.

  The partial flange 532 includes a protruding portion 532A that extends between the pitches of the first spot welds SP1 in the outer peripheral flange portion 433. For this reason, it arrange | positions with sufficient balance in the circumferential direction of the outer side curved part L1 with the junction part of half crack pipes 43A and 43B, and each junction part of half crack pipes 43A and 43B, and the upper and lower covers 53A and 53B. Can do.

[Description of Modified Embodiment]
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to this, A various deformation | transformation embodiment can be taken.

  (1) In the above embodiment, the example in which the sound absorbing material 7 and the sound absorbing material covers (upper and lower covers 53A, 53B) are attached to both the first and second half-broken tubes 43A, 43B is shown. The sound absorbing material 7 and the sound absorbing material cover may be attached to at least one of the first half cracked tube 43A or the second half cracked tube 43B.

  (2) In the above embodiment, as an example of the exhaust pipe, the exhaust introduction pipe 3 and the first and second exhaust lead-out pipes 4A and 4B are arranged symmetrically on the left and right sides thereof, and the first and second exhaust lead-out pipes 4A 4B shows an example in which the bending tube 43 constitutes a part of each of 4B. This is an example, and one exhaust outlet pipe may be used. Further, a curved pipe that is curved in a U shape may constitute a part of the exhaust introduction pipe 3. Furthermore, in the present embodiment, the curved pipe 43 that changes the exhaust path by 180 ° is exemplified, but it is sufficient that the exhaust pipe is curved in a U shape, and the curve is slightly looser than 180 °, or slightly curved beyond 180 °. Also good.

  (3) The partial flanges 532 (second flange portions) of the upper and lower covers 53A and 53B are such that the upper and lower flange portions 433A and 433B (first flange portions) and the second spot welds SP2 can be formed. As long as it has the protrusion part 532A which overlaps, and has the regressing part 532B which exposes both to the extent possible, the 1st spot weld part SP1 of upper and lower flange part 433A, 433B is the shape. . Further, when the bending diameter of the bending tube 43 is relatively large, a partial flange may be provided also on the inner peripheral portion L4 side.

1 Engine 10 Exhaust device 2 Main silencer (Exhaust silencer)
20 Silencer body 27 Set plate 273 Burring part (support opening)
3 Exhaust pipe (exhaust pipe)
4A First exhaust outlet pipe (exhaust pipe)
4B Second exhaust outlet pipe (exhaust pipe)
41 1st straight pipe (connection pipe)
412 Downstream end (one end of connecting pipe)
42 Second straight pipe (connecting pipe)
43 Curved tube 43A First half cracked tube 43B Second half cracked tube 431 Upstream end (end)
432 Downstream end (end)
433 Outer flange part 433A Upper flange part (first flange part)
433B Lower flange (first flange)
434 Inner flange portion 435 Non-flange portion 53A Upper cover (sound absorbing material cover)
53B Lower cover (Sound absorbing material cover)
532 Partial flange (second flange)
533 Line joint portion L1 Outer curved portion L2 Inner curved portion L3 Outer peripheral portion L4 Inner peripheral portion S Silencing space SP1 First spot welded portion (joining at the first position)
SP2 2nd spot weld (joint at 2nd position)

Claims (6)

A silencer body that forms a silencing space where engine exhaust is introduced,
An exhaust pipe that forms an exhaust path through which the exhaust passes in the silencing space and includes a curved pipe that is curved at least in a U-shape;
A sound absorbing material disposed on the outer peripheral surface of the bending tube and a sound absorbing material cover covering the sound absorbing material,
The curved pipe is composed of a joined body in which a pair of half-cracked pipes each having a first flange portion are joined at a predetermined first position in an overlapping portion of the first flange portions, and the sound absorbing material and the sound absorbing material The material cover is attached to at least one of the half cracked tubes,
The sound absorbing material cover has a second flange portion that is joined to the first flange portion at a second position different from the first position;
The exhaust silencer for an engine, wherein the second flange portion has a shape overlapping with the first flange portion at least at a position excluding the first position. The engine exhaust silencer according to claim 1,
The sound absorbing material cover includes an outer peripheral portion along the outer curved portion of the curved tube curved in a U shape, and an inner peripheral portion along the inner curved portion,
The second flange portion extends along the outer peripheral portion,
An exhaust silencer for an engine, wherein the inner peripheral portion is provided with a line joint portion with respect to the outer peripheral surface of the half cracked tube. The engine exhaust silencer according to claim 2,
Each of the half-cracked pipes includes, as the first flange portion, an outer peripheral flange portion along the outer curved portion and an inner peripheral flange portion along the inner curved portion, and in the outer peripheral flange portion and the inner peripheral flange portion, A pair of half cracked tubes are joined by spot welding,
The second flange portion of the sound absorbing material cover is a partial flange extending between the spot welding pitches in the outer peripheral flange portion, and the outer peripheral flange portion and the partial flange are joined by spot welding,
The engine exhaust silencer, wherein the wire joint is line-welded to the outer peripheral surface of the half cracked tube at a position spaced from the inner peripheral flange. The engine exhaust silencer according to any one of claims 1 to 3,
A set plate for supporting the bending tube by the silencer body;
The exhaust pipe further includes a connection pipe having one end connected to an end of the curved pipe,
The end portion of the bending tube is a non-flange portion where the first flange portion does not exist,
The one end of the connecting pipe is inserted into the non-flange portion;
The engine exhaust silencer, wherein the set plate includes a support opening through which the non-flange portion is inserted, and supports the non-flange portion into which the one end of the connection pipe is inserted. The engine exhaust silencer according to claim 4,
The exhaust silencer for an engine, wherein the one end of the connection pipe is inserted to a position that reaches the first flange part beyond the non-flange part of the curved pipe. The engine exhaust silencer according to any one of claims 1 to 5,
The exhaust pipe includes an exhaust introduction pipe that introduces engine exhaust into the silencing space, and an exhaust lead-out pipe that discharges the exhaust from the silencing space to the outside.
The exhaust pipe muffler for an engine, wherein the curved pipe constitutes a part of the exhaust lead-out pipe in the silence space.

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