JP2016217152A - Muffler structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a muffler structure which can reduce a muffler radiation sound while having a heat insulation effect, in a configuration in which an exhaust pipe is inserted into a muffler body.SOLUTION: A muffler structure comprises: a muffler body 18 which is configured while including an outer cylinder 24 and an inner cylinder 26 arranged inside the outer cylinder 24, and into which an exhaust gas is introduced from an exhaust pipe 12 inserted to the inside; and an irregular part 26A which is formed in a region to which the exhaust gas introduced from the exhaust pipe 12 is blown in the inner cylinder 26, and in which a recess 26B recessed in a direction separating from the outer cylinder 24, and forming an air layer between the outer cylinder 24 and itself, and a protrusion 26C which abuts on the outer cylinder 24 are alternately formed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a muffler structure.

  Patent Document 1 discloses an exhaust muffler in which a muffler body is constituted by an outer cylinder and an inner cylinder. Moreover, the structure by which the space between the outer cylinder and the inner cylinder was filled with the heat insulation and the sound deadening material is disclosed.

JP 2008-240611 A

  By the way, in order to avoid stress concentration on the connection portion between the exhaust pipe and the muffler main body, the exhaust pipe may be inserted into the muffler main body to connect the exhaust pipe and the muffler main body at a plurality of locations. However, in the above configuration, exhaust gas introduced into the muffler body may be blown locally on the inner surface of the muffler body to generate muffler sound. For this reason, there is room for improvement from the viewpoint of effectively reducing muffler radiation.

  In view of the above facts, an object of the present invention is to obtain a muffler structure capable of reducing muffler radiation sound while providing a heat insulating effect in a configuration in which an exhaust pipe is inserted into the muffler body.

  The muffler structure according to the first aspect of the present invention includes an outer cylinder and an inner cylinder disposed inside the outer cylinder, and a muffler body into which exhaust gas is introduced from an exhaust pipe inserted to the inside. And in the inner cylinder, a recess that is formed in a portion to which the exhaust gas introduced from the exhaust pipe is sprayed, is recessed in a direction away from the outer cylinder, and forms an air layer between the outer cylinder and the inner cylinder And a concavo-convex portion in which convex portions abutting on the outer cylinder are alternately formed.

  In the muffler structure according to the first aspect of the present invention, a muffler main body is configured including an outer cylinder and an inner cylinder, and an exhaust pipe is inserted into the muffler main body. And exhaust gas is introduce | transduced into a muffler main body from this exhaust pipe. Further, the inner cylinder is provided with uneven portions in which concave portions and convex portions are alternately formed. Here, the concavo-convex portion is formed at a site where the exhaust gas introduced into the muffler body is sprayed. Moreover, the recessed part which comprises an uneven | corrugated | grooved part is dented in the direction spaced apart from an outer cylinder, and the air layer is formed between the inner cylinder and the outer cylinder by this recessed part. Thereby, even when exhaust gas is sprayed on the concavo-convex portion and the concavo-convex portion becomes high temperature, heat conduction from the inner cylinder to the outer cylinder can be suppressed by the air layer. That is, a heat insulation effect can be obtained as compared with a configuration in which an air layer is not formed at a site where exhaust gas is sprayed.

  Moreover, the convex part which comprises an uneven | corrugated | grooved part is contact | abutting to the outer cylinder. Thereby, the bending rigidity of the site | part to which the exhaust gas in a muffler main body is sprayed can be improved, and the vibration of this site | part can be suppressed. As a result, muffler radiation sound can be effectively reduced.

  As described above, according to the muffler structure according to the present invention, muffler radiation sound can be reduced while providing a heat insulating effect in the configuration in which the exhaust pipe is inserted into the muffler main body.

It is a top view which shows the muffler structure which concerns on embodiment. It is an expanded sectional view which expands and shows the state cut | disconnected by the 2-2 line | wire of FIG. It is a perspective view which shows the muffler structure which concerns on embodiment. It is a perspective view corresponding to Drawing 3 showing the modification of the muffler structure concerning an embodiment.

(Overall configuration of exhaust system)
A muffler structure according to an embodiment of the present invention will be described with reference to FIGS. Note that an arrow FR appropriately shown in each drawing indicates a vehicle front side of a vehicle to which a muffler structure is applied, an arrow UP indicates a vehicle upper side, and an arrow OUT indicates an outer side in the vehicle width direction. . Further, in the following description, when using the front / rear, up / down, and left / right directions, the front / rear direction of the vehicle, the up / down direction of the vehicle up / down direction, and the left / right direction in the traveling direction are indicated.

  As shown in FIG. 1, the muffler structure includes a main muffler 10 for reducing exhaust noise. The main muffler 10 is formed in a substantially rectangular shape with the vehicle width direction as a longitudinal direction in plan view, and an exhaust pipe 12 is connected to the center portion of the main muffler 10 in the vehicle width direction.

  The exhaust pipe 12 is connected to the front end portion of the main muffler 10 and is inserted to the inside of the main muffler 10 (see FIG. 2). Further, the exhaust pipe 12 extends from the main muffler 10 to the vehicle front side. The front end of the exhaust pipe 12 is connected to an engine (not shown) that is an internal combustion engine.

  In addition, a catalytic converter and a sub-muffler (not shown) are arranged between the engine and the main muffler 10. The catalytic converter is configured to purify harmful components in exhaust gas discharged from the engine by reduction and oxidation. The sub muffler is configured to absorb exhaust sound (high frequency component) that cannot be absorbed by the main muffler 10. The exhaust system of the present embodiment is configured as described above, and exhaust gas generated by engine combustion or the like passes through a catalytic converter and a sub-muffler (not shown) via the exhaust pipe 12 and is introduced into the main muffler 10. .

  An exhaust pipe 14 is connected to the vehicle right side of the main muffler 10. The exhaust pipe 14 communicates with the internal space of the main muffler 10, extends from the main muffler 10 to the right side of the vehicle, and is further curved toward the rear side of the vehicle. The exhaust gas introduced into the main muffler 10 is configured to be discharged into the atmosphere through the exhaust pipe 14.

  The internal space of the main muffler 10 is partitioned by a plurality of separators 16 and is partitioned by two separators 16 as an example in the present embodiment. The two separators 16 are arranged substantially in parallel and are installed inside the main muffler 10, and the internal space of the main muffler 10 is partitioned into three spaces in the vehicle width direction by these separators 16. Here, each separator 16 has a communication hole (not shown) that communicates with an adjacent space. For this reason, the exhaust gas introduced into the main muffler 10 passes through a communication hole (not shown) and travels through a space partitioned by the separator 16, and the exhaust noise is reduced in the process. In addition, since said structure is well-known, illustration and description of a detailed structure are abbreviate | omitted.

(Configuration of main muffler)
As shown in FIG. 3, the main muffler 10 includes a muffler body 18. The muffler body 18 has a hollow structure including a substantially cylindrical peripheral wall portion 20 that is open at both ends in the vehicle width direction and a substantially flat side wall portion 22 that closes the openings at both ends of the peripheral wall portion 20 in the vehicle width direction. It is said that.

  The side wall portion 22 is formed to have a larger diameter than the cross-sectional shape of the peripheral wall portion 20 viewed from the vehicle width direction, and the outer peripheral end portion of the side wall portion 22 protrudes to the outer peripheral side from the peripheral wall portion 20. Further, a support member for assembling the main muffler 10 to the vehicle body is attached to the side wall portion 22.

  On the other hand, as shown in FIG. 2, the peripheral wall portion 20 includes an outer cylinder 24 serving as an outer plate and an inner cylinder 26 serving as an inner plate, and has a cross-sectional shape viewed from the vehicle width direction. It is formed in a substantially elliptical shape in which the vehicle vertical direction is the minor axis direction. A hemming portion 20B is provided at the rear end portion of the peripheral wall portion 20. In the hemming portion 20B, one end side of the outer cylinder 24 and the inner tube 26 constituting the peripheral wall portion 20 and the other end side of the outer tube 24 and the inner tube 26 are coupled by hemming processing to form a closed cross section. doing. Further, the outer cylinder 24 and the inner cylinder 26 are in close contact except for an uneven portion 26A described later.

  A pipe insertion hole 20 </ b> A is formed at the front end of the muffler body 18. The pipe insertion hole 20A is formed in the vehicle width direction center part of the peripheral wall part 20, and the tip part 30 of the exhaust pipe 12 is inserted into the pipe insertion hole 20A.

  Further, an outer cylinder 24 and an inner cylinder 26 extend from the hole edge of the pipe insertion hole 20 </ b> A toward the outside of the muffler body 18, and are joined to the outer peripheral surface of the distal end portion 30 of the exhaust pipe 12. Further, a substantially cylindrical reinforcing plate 28 is joined to the outer surface of the muffler main body 18 to reinforce the joint portion between the muffler main body 18 and the exhaust pipe 12.

  Here, the distal end portion 30 of the exhaust pipe 12 is inserted to the inside of the muffler main body 18. The tip 30 is supported by a support plate 32 installed inside the muffler body 18.

  The support plate 32 is a substantially flat plate-like member disposed in the vicinity of the pipe insertion hole 20A in the muffler body 18, and the vehicle lower side is positioned on the vehicle rear side rather than the vehicle upper side with the vehicle longitudinal direction as the plate thickness direction. It is arranged so as to be inclined. Further, an outer flange portion 32A bent toward the vehicle rear side along the inner surface of the inner cylinder 26 is formed at the outer peripheral end of the support plate 32, and the outer flange portion 32A and the inner cylinder 26 are joined. ing.

  The support plate 32 has a through hole 32B at a position facing the pipe insertion hole 20A. The through hole 32B is formed to be approximately the same size as the pipe insertion hole 20A, and the tip portion 30 is inserted into the through hole 32B. Furthermore, an inner flange portion 32C extends from the hole edge of the through hole 32B to the vehicle rear side, and the inner flange portion 32C is joined to the outer peripheral surface of the tip portion 30. On the other hand, two annular protrusions 30 </ b> A and 30 </ b> B are formed on the outer peripheral surface of the tip portion 30 with an interval in the axial direction. The inner flange portion 32C of the support plate 32 is sandwiched between the annular protrusion portions 30A and 30B, and the leading end portion 30 is prevented from being pulled out by the annular protrusion portions 30A and 30B. In this way, by connecting the exhaust pipe 12 to the muffler main body 18 at a plurality of locations (in this embodiment, two locations), the stress acting on the connection portion can be dispersed, and the connection state is improved. Can be maintained.

  Here, the inner cylinder 26 constituting the peripheral wall portion 20 of the muffler main body 18 is formed with a concavo-convex portion 26A having a substantially wave shape in cross-section when viewed from the vehicle width direction by the plurality of concave portions 26B and the plurality of convex portions 26C. Has been.

  The concavo-convex portion 26 </ b> A is formed at a site where the exhaust gas introduced into the muffler body 18 is sprayed. Specifically, it is formed from the position offset from the vehicle front-rear direction center in the upper part of the peripheral wall 20 to the front side of the vehicle over the rear end of the peripheral wall 20.

  Further, the plurality of concave portions 26B and the plurality of convex portions 26C constituting the uneven portion 26A are alternately formed along the vehicle front-rear direction. Here, each recess 26 </ b> B is formed by recessing the inner cylinder 26 in a direction away from the outer cylinder 24 (inside the muffler body 18). Moreover, each recessed part 26B is extended in the vehicle width direction between a pair of side wall parts 22, and is formed in groove shape (refer FIG. 3). For this reason, a gap (air layer) is formed between the inner cylinder 26 and the outer cylinder 24 at the portion where the recess 26 </ b> B is formed.

  On the other hand, the convex portion 26C is provided by not forming the concave portion 26B between the concave portions 26B adjacent to each other in the vehicle front-rear direction, and is formed as a convex rib extending in the vehicle width direction. Yes. Further, the top of the convex portion 26 </ b> C is in contact with the inner surface of the outer cylinder 24. For this reason, the air layer between the inner cylinder 26 and the outer cylinder 24 is divided in the vehicle front-rear direction by the convex portion 26C.

(Action and effect)
Next, the operation and effect of the muffler structure according to this embodiment will be described.

  In the muffler structure of the present embodiment, an uneven portion 26A having a corrugated cross section is formed at a portion of the inner tube 26 where the exhaust gas is sprayed. A plurality of air layers are provided between the first and second air layers. Thus, the heat insulation effect can be obtained by interposing the air layer between the outside of the muffler body 18 and the internal space.

  More specifically, the exhaust gas discharged from the engine to the exhaust pipe 12 passes through a catalytic converter and a sub-muffler (not shown) and passes through a tip 30 inserted from the pipe insertion hole 20 </ b> A to the inside of the muffler body 18. It is introduced into the main body 18. And the exhaust gas introduced into the inside of the muffler main body 18 is sprayed to the uneven part 26A.

  Here, an air layer is provided between the outer cylinder 24 and the inner cylinder 26 in the concavo-convex portion 26 </ b> A, and is insulated by this air layer. For this reason, a heat insulation effect can be acquired compared with the structure (structure with which the outer cylinder 24 and the inner cylinder 26 are closely_contact | adhered) in which the uneven | corrugated | grooved part 26A is not provided in the site | part where exhaust gas is sprayed.

  In particular, in the present embodiment, the distal end portion 30 of the exhaust pipe 12 is inserted into the muffler main body 18 in order to ensure the connection strength between the exhaust pipe 12 and the muffler main body 18. For this reason, the exhaust gas introduced into the muffler body 18 is guided to the tip portion 30 and sprayed onto the uneven portion 26A, and the temperature of the uneven portion 26A is likely to rise. Even in such a case, heat conduction from the inner cylinder 26 to the outer cylinder 24 can be suppressed by the air layer. Compared with a configuration in which a heat insulating material is wound around the outer surface of the peripheral wall portion 20 and a structure in which a heat insulating material is filled between the outer tube 24 and the inner tube 26, the number of parts is reduced and the material cost is increased. Can be suppressed.

  Further, in the present embodiment, the convex portion 26C is provided on the concave and convex portion 26A, and the top portion of the convex portion 26C is brought into contact with the outer cylinder 24. Thereby, the bending rigidity of this part can be improved compared with the structure by which the clearance gap was continuously formed between the outer cylinder 24 and the inner cylinder 26. FIG. By the way, the muffler radiated sound is generated when exhaust gas is blown into the muffler main body 18 and the inner cylinder 26 vibrates. Therefore, the muffler radiated sound is reduced by increasing the bending rigidity of this portion and reducing the vibration. Can be effectively reduced.

  Moreover, in this embodiment, the uneven | corrugated | grooved part 26A is formed in the site | part to which exhaust gas is sprayed, and the uneven | corrugated | grooved part 26A is not formed in the other site | part. Thereby, a moldability can be improved compared with the structure which formed the whole surrounding wall part 20 in the cross-sectional wave shape.

  Although the muffler structure according to the embodiment of the present invention has been described above, it is needless to say that the present invention can be implemented in various modes without departing from the gist of the present invention. For example, in the present embodiment, as shown in FIG. 2, the distal end portion 30 of the exhaust pipe 12 is extended to the vehicle rear side from the support plate 32, but is not limited thereto. That is, the distal end portion 30 may terminate at the position of the support plate 32.

  Moreover, although the uneven | corrugated | grooved part 26A of this embodiment is formed with the several recessed part 26B and the several convex part 26C so that the cross-sectional shape seen from the vehicle width direction may become a substantially wave shape, it is not limited to this. For example, you may form several recessed part 26B and several convex part 26C so that the cross-sectional shape seen from the vehicle front-back direction may become a substantially wave shape. Even in this case, since an air layer is formed between the outer cylinder 24 and the inner cylinder 26, a heat insulating effect is provided. Further, by bringing the top of the convex portion 26C into contact with the outer cylinder 24, the bending rigidity of this portion can be increased, and the muffler radiation sound is reduced.

  Further, in the present embodiment, as shown in FIG. 3, an uneven portion 26A is formed between a pair of side wall portions 22 constituting the muffler body 18, and exhaust gas is sprayed over the entire area of the uneven portion 26A. However, the present invention is not limited to this. For example, as in the modification shown in FIG. 4, the uneven portion 60 </ b> A may be formed only on a part of the muffler main body 52 in the vehicle width direction.

  As shown in FIG. 4, the main muffler 50 to which the muffler structure according to this modification is applied includes a muffler main body 52, and the muffler main body 52 includes a peripheral wall portion 54 and a side wall portion 56. Has been. In addition, the peripheral wall part 54 and the side wall part 56 which concern on this modification are set as the structure similar to the peripheral wall part 20 and the side wall part 22 of FIG. Further, the peripheral wall portion 54 according to this modification is formed longer in the vehicle width direction than the peripheral wall portion 20 of FIG. 3, but is not limited to this, and is formed to have substantially the same dimensions as the peripheral wall portion 20 of FIG. 3. May be.

  The peripheral wall portion 54 is configured to include an outer cylinder 58 serving as an outer plate and an inner cylinder 60 serving as an inner plate, and the cross-sectional shape viewed from the vehicle width direction is substantially the minor axis direction of the vehicle vertical direction. It is formed in an elliptical shape.

  Here, the inner cylinder 60 constituting the peripheral wall portion 54 of the muffler main body 52 is provided with an uneven portion 60A having a corrugated cross section by a plurality of concave portions 60B and a plurality of convex portions 60C. The uneven portion 60 </ b> A has the same configuration as the uneven portion 26 </ b> A of FIG. 3, and is formed at a site where the exhaust gas introduced into the muffler main body 52 is sprayed. In the present modification, the uneven portion 60A is formed only in the center portion of the peripheral wall portion 54 in the vehicle width direction.

  In the muffler structure according to the modified example configured as described above, the muffler radiated sound can be effectively reduced by increasing the rigidity of the part that is likely to cause the muffler radiated sound. Moreover, it can insulate effectively by forming an air layer in the site | part which becomes high temperature easily. Furthermore, since the area | region to shape | mold becomes narrow compared with the Example shown by FIG. 3, a moldability can be improved.

12 Exhaust pipe 18 Muffler main body 24 Outer cylinder 26 Inner cylinder 26A Concavity and convexity 26B Concavity 26C Convex part 52 Muffler main body 58 Outer cylinder 60 Inner cylinder 60A Concavity and convexity 60B Concavity 60C Convex part

Claims (1)

A muffler main body configured to include an outer cylinder and an inner cylinder disposed inside the outer cylinder, into which exhaust gas is introduced from an exhaust pipe inserted to the inside,
In the inner cylinder, a recess formed in a portion to which the exhaust gas introduced from the exhaust pipe is blown and recessed in a direction away from the outer cylinder to form an air layer between the outer cylinder and the outer cylinder Concavo-convex parts formed alternately with convex parts abutting on,
A muffler structure.

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